JP4401392B2 - Wireless communication apparatus, wireless communication method, wireless communication system, program, and storage medium storing program - Google Patents

Description

  The present invention relates to a wireless communication device, a wireless communication method, a wireless communication system, a program product, and a storage medium that stores the program product.

  Conventionally, devices such as personal computers installed in offices and homes are connected by a LAN (Local Area Network) cable or the like. However, when connecting devices using a LAN cable or the like, there are problems such as complicated wiring and a low degree of freedom in moving the devices. In recent years, in order to solve such problems, devices such as personal computers installed in offices and homes use a wireless transmission technology such as a wireless LAN standardized by IEEE 802.11.

  Since the wireless LAN is an extension of the LAN to a wireless network, it is suitable for data transfer such as data file transfer and Web access between personal computers. In the market, products such as wireless LAN cards for notebook personal computers and wireless LAN access points are widely sold.

  Recently, development of wireless transmission technology for transmitting real-time data with high quality has been promoted. IEEE 802.11e, which is currently being standardized, is for enabling communication quality (QoS (Quality of Service)) control over a wireless LAN, and is attracting attention. IEEE802.11e provides two access control methods, EDCA (Enhanced Distributed Channel Access) and HCCA (HCF (Hybrid Coordination Function) Controlled Channel Access) for QoS control (for example, Non-Patent Document 1).

  EDCA is a distributed control type access control method that allows each wireless communication device to access a channel stochastically. More specifically, a wireless communication device (hereinafter also referred to as a “transmission station”) that intends to transmit data first checks whether other wireless communication devices in the wireless communication system are not transmitting data. . When the transmitting station confirms that there is no other wireless communication device that is transmitting data, it sets a random waiting time to transmit data. At this time, the transmitting station sets the waiting time length according to the priority of the data. The transmitting station starts transmitting data after the waiting time has elapsed. The central control station (QAP (QoS Access Point)) sets the above-described waiting time to a value having a certain range for each priority, and notifies and designates the waiting time to all transmitting stations. QAP can adjust the overall wireless communication situation to some extent by changing the value and range of the above-mentioned waiting time. In EDCA, the waiting time set by the transmitting station is random, and data transmitted from each transmitting station may collide. When data transmitted from each transmitting station collides, data transmission is not performed normally. Thus, since EDCA does not guarantee that data can be reliably transmitted in time, it is not well suited for transmitting real-time data.

  In contrast, HCCA is a central control type access control system that allows each wireless communication device to access a channel deterministically under the direction of QAP (granting communication rights (notifying a poll frame)). is there. More specifically, the transmitting station requests the QAP to give a communication time during which data can be transmitted (hereinafter also referred to as “communication band”). The QAP controls the grant or release of a communication band necessary for the transmitting station to transmit data. In terms of specifications, QAP is free to give a transmission band to a transmission station, but generally, if a free communication band corresponding to a communication band requested from a transmission station is left in the wireless communication system, A communication band is added. The transmitting station transmits data using a transmission path determined within the communication band range (communication time) given by the QAP. Since HCCA controls the communication band given to each transmitting station by QAP, data transmitted from each transmitting station does not collide. Therefore, HCCA is suitable for transmission of real-time data or the like that requires a high data rate and that requires transmission of data within a delay time (DelayBound).

  Hereinafter, performing QoS control using HCCA is referred to as “securing the communication band”, and ending QoS control using HCCA is referred to as “releasing the communication band”.

  As a transmission path from a transmission station to a wireless communication apparatus (hereinafter also referred to as “reception station”), a “first transmission path (Directlink)” directly from the transmission station to the reception station, and a transmission station to a relay station A “second transmission path” that reaches a receiving station via a wireless communication device (hereinafter also simply referred to as “relay station”). If QoS control is performed using HCCA, the communication band of each transmission path needs to be given from QAP.

  When transmitting data from the transmitting station to the receiving station, it is appropriate to transmit data using the first transmission path (Directlink) or the second transmission path depending on the communication status. Different. In general, when the distance between the transmitting station and the receiving station is short, it is often the case that data is transmitted using the first transmission path (Directlink), and the communication status is better, and transmission can be performed with good quality. . On the other hand, when the distance between the transmitting station and the receiving station is long and there is a relay station between the transmitting station and the receiving station, it is better to transmit data using the second transmission path, and the quality is better. In many cases, transmission can be performed.

  For example, it is assumed that the transmitting station is a DVD (Digital Versatile Disc) player that reproduces video and audio. On the other hand, it is assumed that the receiving station is a television or the like that receives data transmitted from a DVD player or the like as a transmitting station and outputs video and audio to a screen or a speaker. Since the wireless connection between the TV or the like and the DVD player or the like can be used while moving the TV or the like.

  When using a television or the like while moving, the communication status with the DVD player or the like changes from time to time. For this reason, in order to transmit data with high quality to a television or the like, a DVD player or the like appropriately switches between the first transmission path (Directlink) and the second transmission path according to the communication status is one solution. It is also important to perform QoS control using IEEE 802.11e even after switching the transmission path.

Thus, regarding the method of changing the QoS control using IEEE802.11e when the transmission path is switched, there is no document that discloses the method. When EDCA is used, it can be easily analogized that the priority (priority) of the transmitting station should be increased so that the switched transmission path can be accessed with higher probability than other wireless communication apparatuses. When HCCA is used, a method of requesting the provision of the communication band of the transmission path after switching after releasing the communication band of the transmission path before switching can be easily inferred. As another method, a method of requesting both the communication bandwidths of the first transmission path and the second transmission path can be easily analogized.
“P802.11e, (D11) Draft Amendment to Standard [for] for Information Technology”, [Online], [searched on November 11, 2004], Internet <URL: http://www.ili-info.com /ieee802drafts/index.shtml>

  However, in the method of requesting the addition of the communication band of the transmission path after switching after the communication band of the transmission path before switching is released, the transmission path of the transmission path after switching is released after releasing the communication band of the transmission path before switching. There is a problem that there is a period in which no communication band is provided between the time when the communication band is requested and the time when the communication band is provided from the QAP, and the real-time property of data transmission is impaired.

  The transmitting station cannot transmit data to the receiving station during a period in which no communication band is given. As a result, there is a possibility that the delay time exceeds the DelayBound value permitted for transmission (for example, a recommended value of 64 msec in the case of transmission of a television video signal). For example, as described above, when the receiving station is a television or the like, if the delay time exceeds the DelayBound value, the real-time property of data transmission is impaired, and video and audio are disturbed.

  In addition, after releasing the communication band of the transmission path before switching and requesting the addition of the communication band of the transmission path after switching and giving the communication band from the QAP, other users and applications may Communication bandwidth may be consumed to transmit data. As a result, the communication bandwidth of the transmission path after switching from QAP becomes difficult to be given, the period when the communication bandwidth is not given becomes longer and the real-time property of data transmission is impaired.

  Further, when switching from the first transmission path (Directlink) to the second transmission path, the QAP is requested for the communication band of the transmission path from the transmitting station to the relay station and the communication band of the transmission path from the relay station to the receiving station. There is a need. That is, after switching, it is necessary to request the QAP to give about twice as much communication bandwidth as before switching. Therefore, it becomes difficult to give the communication band of the transmission path after switching from QAP, and if the communication band of the transmission path before switching is released, the period when the communication band is not given becomes longer and the data transmission Real-time performance is impaired.

  Further, since the communication band of the transmission path after switching from the QAP is not granted, even if the QAP requests the provision of the communication band of the transmission path before the switching, other data or other data has already been requested by another user or application at that time. There is a possibility that the communication band is consumed for transmission. As a result, it becomes difficult to give the communication band of the transmission path before switching from the QAP, and in the worst case, the communication band of the first transmission path (Directlink) or the second transmission path cannot be secured, and the transmission station to the reception station There arises a problem that the data transmission to the network ends.

  In addition, regarding the method for requesting both the communication bands of the first transmission line and the second transmission line, since the requested communication band amount is large, the communication bands of the first transmission line and the second transmission line are hardly given from the QAP. Further, even if the communication bands of the first transmission path and the second transmission path are given, the data transmission is performed by switching the communication band of either one of the transmission paths, so the communication band of the other transmission path is wasted. There is also a problem of consuming communication bandwidth.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a wireless communication apparatus capable of switching a transmission path without impairing real-time performance of data transmission.

  Another object of the present invention is to provide a wireless communication method capable of performing communication by switching the transmission path without impairing the real-time property of data transmission.

  Another object of the present invention is to provide a wireless communication system capable of performing communication by switching transmission lines without impairing the real-time property of data transmission.

  Another object of the present invention is to provide a program for causing a computer to function as a wireless communication apparatus capable of switching transmission paths without impairing real-time performance of data transmission.

  Still another object of the present invention is to provide a storage medium storing a program for causing a computer to function as a wireless communication apparatus capable of switching transmission lines without impairing real-time data transmission.

  In order to achieve the above-described object, a wireless communication device according to an aspect of the present invention includes a transmission / reception unit that transmits / receives data to / from another wireless communication device via a plurality of transmission paths, and a center that assigns and releases a communication band. A communication band control unit that controls the communication band so as to use the communication band given to a certain transmission path from the control station as the communication band of another transmission path not given the communication band.

  Preferably, the transmission path includes a first transmission path that directly transmits data to another wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station. The communication band control unit instructs the relay station to request the central control station to give a communication band to the third transmission path from the relay station to another wireless communication device in the second transmission path. An other band grant request instruction unit is included.

  Preferably, the communication band control unit includes an other band release request instructing unit that instructs the relay station to request the central control station to release the communication band of the third transmission path.

  Preferably, the transmission path includes a first transmission path that directly transmits data to another wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station. The wireless communication apparatus further includes a wireless communication control unit that switches a transmission path used for transmitting data to another wireless communication apparatus between the first transmission path and the second transmission path.

  Preferably, when the wireless communication control unit switches the transmission path from the first transmission path to the second transmission path, in the switching process, the communication band on the first transmission path and another wireless station from the relay station in the second transmission path. After passing through the state in which the communication band on the third transmission path to the communication device is assigned, the state in which all the communication bands of the first transmission path and the second transmission path are assigned is passed.

  Preferably, when the wireless communication control unit switches the transmission path from the second transmission path to the first transmission path, in the switching process, the communication band on the fourth transmission path from its own device to the relay station in the second transmission path. After passing through the state in which only the transmission line is assigned, the state in which the communication bands of the first transmission line and the fourth transmission line are assigned passes.

  Preferably, the communication band control unit uses the transmission path before switching when the transmission path used for transmitting data to another wireless communication apparatus is switched between the first transmission path and the second transmission path. Control for transmitting data indicating that data is being transmitted to another wireless communication apparatus to the central control station is executed.

  Preferably, the wireless communication device further includes a notification unit that notifies a status of processing for switching a transmission line used for transmitting data to another wireless communication device between the first transmission line and the second transmission line.

  Preferably, the wireless communication device sets a relay destination address setting unit that sets a relay destination address for specifying a relay station that relays data, and a reception destination address for specifying a wireless communication device that receives data. A receiving address setting unit; When the wireless communication control unit switches from the first transmission path to the second transmission path, the relay destination address setting unit sets the relay destination address in order to transmit data to the relay station in the communication band already assigned by the central control station. The address of the relay station is set, and the receiving address setting unit sets the receiving address to the address of another wireless communication device.

  Preferably, when the wireless communication control unit switches from the second transmission path to the first transmission path, a relay destination address is used to directly transmit data to another wireless communication apparatus in the communication band already assigned by the central control station. The setting unit does not set the relay destination address, and the reception destination address setting unit sets the reception destination address to the address of another wireless communication device.

  Preferably, the communication band control unit requests the central control station to provide a communication band for transmitting data to other wireless communication devices, and currently determines whether or not the communication band is provided from the central control station. The wireless communication system to which the apparatus belongs includes a free bandwidth confirmation unit that confirms whether or not there is a free communication bandwidth.

  Preferably, the wireless communication control unit stops switching between the first transmission path and the second transmission path when the free bandwidth confirmation unit confirms that the free bandwidth is insufficient.

  A wireless communication device according to another aspect of the present invention receives data from a transmission-side wireless communication device via a transmission line, and transmits the received data to the reception-side wireless communication device via a transmission line. The transmission path includes a first transmission path that directly transmits data to another wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station. The wireless communication apparatus requests the central control station that assigns and releases the communication band to assign the communication band to the third transmission path from the relay station of the second transmission path to the other wireless communication apparatus. Thus, when instructed by another wireless communication device, the other band grant request control unit that requests the central control station to grant the communication band of the third transmission path, and the communication band has been given to the third transmission path And an attached data transmission control unit that controls transmission of data indicating.

  Preferably, when the wireless communication apparatus is instructed by another wireless communication apparatus to request the central control station to release the communication band of the third transmission path, the third transmission path is transmitted to the central control station. And an open data transmission control unit for controlling transmission of data indicating that the communication band of the third transmission path has been released.

  According to another aspect of the present invention, a wireless communication method for transmitting and receiving data between a first wireless communication device and a second wireless communication device through a plurality of transmission paths is provided. This method includes a step of detecting a communication band assigned to a certain transmission path from a central control station that assigns and releases a communication band, and another transmission path to which no communication band is assigned. And a communication band control step for controlling the detected communication band so as to be used as the communication band.

  Preferably, the plurality of transmission paths include a first transmission path that directly transmits data from the first wireless communication apparatus to the second wireless communication apparatus, and a relay station from the first wireless communication apparatus to the second wireless communication apparatus. And a second transmission path for transmitting data through the network. The wireless communication method instructs the relay station to request the central control station to give a communication band to the third transmission path from the relay station of the second transmission path to the second wireless communication apparatus. It further includes an other band grant request instruction step.

  Preferably, the wireless communication method further includes an other band release request instruction step for instructing the relay station to request the central control station to release the communication band of the third transmission path.

  Preferably, the plurality of transmission paths include a first transmission path that directly transmits data from the first wireless communication apparatus to the second wireless communication apparatus, and a relay station from the first wireless communication apparatus to the second wireless communication apparatus. And a second transmission path for transmitting data through the network. The wireless communication method further includes a wireless communication control step of switching a transmission path used for transmitting data to the second wireless communication apparatus between the first transmission path and the second transmission path.

  Preferably, when the wireless communication control step switches from the first transmission path to the second transmission path, the communication band on the first transmission path and the second wireless communication from the relay station in the second transmission path in the switching process After passing through the state where the communication band on the third transmission path up to the device is assigned, the state where all the communication bands on the first transmission path and the second transmission path are assigned passes.

  Preferably, when the wireless communication control step switches from the second transmission path to the first transmission path, the communication band on the fourth transmission path from the first wireless communication device to the relay station in the second transmission path in the switching process. After passing through the state in which only communication is given, the state in which the communication bands on the first transmission line and the fourth transmission line are given passes.

  Preferably, when the wireless communication control step switches from the first transmission path to the second transmission path, at least the communication band on the first transmission path and the central control station from the relay station of the second transmission path to the second transmission path in the switching process. The state in which the communication band on the third transmission path to the second wireless communication device is given passes.

  Preferably, when the wireless communication control step switches from the second transmission path to the first transmission path, only the communication band on the fourth transmission path from the first wireless communication device to the relay station in the second transmission path in the switching process. The state in which is given is passed.

  Preferably, the wireless communication method is switched when the transmission path used to transmit data from the first wireless communication apparatus to the second wireless communication apparatus is switched between the first transmission path and the second transmission path. The method further includes the step of transmitting data indicating that data is being transmitted from the first wireless communication apparatus to the second wireless communication apparatus using the previous transmission path to the central control station.

  Preferably, in the wireless communication method, a state of processing for switching a transmission path used for transmitting data from the first wireless communication apparatus to the second wireless communication apparatus between the first transmission path and the second transmission path is set. The step of notifying is further provided.

  Preferably, in the wireless communication method, a relay destination address setting step for setting a relay destination address for specifying a relay destination for relaying data, and a reception destination address for specifying a wireless communication device for receiving data are set. A receiving address setting step. When the wireless communication control step switches the transmission path from the first transmission path to the second transmission path, the relay destination address setting step is relayed in order to transmit data to the relay station in the communication band already assigned from the central control station. The destination address is set to the address of the relay station, and the destination address setting step sets the destination address to the address of the second wireless communication apparatus.

  Preferably, when the wireless communication control step switches from the second transmission path to the first transmission path, a relay destination is used to directly transmit data to the second wireless communication apparatus in the communication band already assigned by the central control station. The address setting step does not set the relay destination address, and the reception destination address setting step sets the reception destination address to the address of the second wireless communication apparatus.

  Preferably, the wireless communication method requests the central control station to provide a communication band for transmitting data to the second wireless communication apparatus, and depending on whether the central control station provides the communication band, The wireless communication system to which one wireless communication device belongs further includes a free bandwidth confirmation step for confirming whether or not there is a free communication bandwidth.

  Preferably, the free band confirmation step requests the central control station to provide a communication band obtained by adding a communication band to be newly added to the communication band that has already been granted from the central control station. Whether or not there is a free communication band in the wireless communication system to which the first wireless communication apparatus currently belongs is determined.

  Preferably, in the free bandwidth confirmation step, it is assumed that transmission of data for a communication band that is newly desired is requested, the central control station is requested to grant the communication band, and the communication bandwidth is granted from the central control station. Whether or not there is a free communication band in the wireless communication system to which the first wireless communication apparatus currently belongs is determined.

  Preferably, the wireless communication method further includes a step of canceling the switching of the transmission path between the first transmission path and the second transmission path when the free bandwidth confirmation step confirms that the free bandwidth is insufficient.

  A wireless communication system according to another aspect of the present invention includes a first wireless communication device and a second wireless communication device connected to the first wireless communication device via a network. The first wireless communication apparatus is assigned to a transmission path from a transmission / reception unit that transmits / receives data to / from the second wireless communication apparatus via a plurality of transmission paths and a central control station that assigns and releases a communication band. A communication band control unit that controls the communication band so that the communication band is used as a communication band of another transmission path to which no communication band is given.

  A wireless communication system according to another aspect of the present invention includes a first wireless communication device and a second wireless communication device connected to the first wireless communication device via a network. The first wireless communication device receives data from a transmission-side wireless communication device via a transmission line, and performs wireless communication as a relay station that transmits the received data to the reception-side wireless communication device via the transmission line. Device. The first wireless communication device transmits the wireless communication on the transmission side so as to request the central control station that assigns and releases the communication band to assign the communication band to the first transmission path to the wireless communication device on the reception side. When instructed by the device, another bandwidth grant request control unit that requests the central control station to grant the communication band of the first transmission path, and transmission of data indicating that the communication band has been given to the first transmission path A provision data transmission control unit for controlling.

  According to another aspect of the present invention, a program product for causing a computer to function as a wireless communication device is provided. This program product transmits a step of transmitting / receiving data to / from another wireless communication device via a plurality of transmission lines, and a communication band assigned to a transmission line from a central control station that assigns and releases a communication band. And a step of controlling the communication band so as to be used as a communication band of another transmission path not provided with the communication band.

  According to another aspect of the present invention, a program product for causing a computer to function as a wireless communication device is provided. The wireless communication device is a wireless communication device as a relay station that receives data from a transmission-side wireless communication device via a transmission line and transmits the received data to the reception-side wireless communication device via the transmission line. . The program product sends a request to the central control station, which assigns and releases the communication band, to the computer to give the communication band to the first transmission path to the receiving wireless communication apparatus. When instructed, the central control station is requested to grant the communication band of the first transmission path, and to control the transmission of data indicating that the communication band has been assigned to the first transmission path. .

  A storage medium according to still another aspect of the present invention stores any of the above program products.

It is a block diagram which shows the outline of the radio | wireless communications system which concerns on embodiment of this invention. It is a functional block diagram which shows schematic structure of the transmission station which concerns on embodiment of this invention. It is a functional block diagram which shows schematic structure of the radio | wireless communication apparatus as a relay station which relays the data which the transmission station which concerns on embodiment of this invention transmitted to the receiving station. The figure showing the provision state of the communication band before the transmission line which concerns on the 1st Embodiment of this invention is switched, and the communication band after the transmission line which concerns on the 2nd Embodiment of this invention is switched It is a figure showing the provision state of. It is a figure (the 1) showing the provision state of the communication band of the transmission path in the middle of switching. It is a figure (the 2) showing the provision state of the communication band of the transmission path in the middle of switching. The figure showing the provision state of the communication band after the transmission line which concerns on the 1st Embodiment of this invention is switched, and the communication band before the transmission line which concerns on the 2nd Embodiment of this invention is switched It is a figure showing the provision state of. It is the flowchart which showed the processing performed when the transmission station used when transmitting data to a receiving station switches from a 1st transmission path (Directlink) to a 2nd transmission path. It is a figure which shows a transmission data sequence. It is a figure which shows a data frame when the transmission station 102 transmits data to the receiving station 103 by relaying QAP101 (relay station). It is a figure which shows a data frame when the transmitting station transmits data directly to the receiving station. It is the figure which showed the mode when a transmitting station transmits data via QAP to a receiving station by utilizing the communication band of a 1st transmission path (Directlink). It is a figure (the 1) showing the provision state of the communication band of the transmission path in the middle of the switching in the 2nd Embodiment of this invention. It is FIG. (2) showing the provision state of the communication band of the transmission path in the middle of the switching in the 2nd Embodiment of this invention. It is the flowchart which showed the process performed when the transmission path used when a transmitting station transmits data to a receiving station is switched from a 2nd transmission path to a 1st transmission path (Directlink). It is a block diagram showing the hardware constitutions of a computer system.

Explanation of symbols

  100 wireless communication system, 101 QAP, 102 transmitting station, 103 receiving station, 104 first transmission line (Directlink), 105 second transmission line, 106 transmission line (Uplink), 107 transmission line (Downlink), 201 CPU, 202 MEM , 203 Transmission data buffer, 204 Reception data buffer, 205 Wireless communication control unit, 206 Modulation / demodulation unit, 207 Antenna, 208 Communication band control unit, 209 Own band grant / release request unit, 210 Free band confirmation unit, 211 Other band grant / Release request instruction unit, 212 relay destination address setting unit, 213 reception destination address setting unit, 214 user notification unit, 300 relay station, 301 CPU, 302 MEM, 303 transmission data buffer, 304 reception data buffer, 305 wireless communication control unit, 30 Modulation / demodulation unit, 307 antenna, 308 communication band control unit, 309 own band grant / release request unit, 310 other band grant / release request control unit, a band secured on first transmission path (Directlink) 104, b transmission path Bandwidth reserved on (Downlink) 107, c Area reserved on transmission line (Uplink) 106.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[First Embodiment]
FIG. 1 is a configuration diagram illustrating an outline of a wireless communication system 100. The wireless communication system 100 includes at least a wireless communication apparatus (hereinafter simply referred to as “central control station” or “QAP”) 101 as a central control station (QAP) and a wireless communication apparatus (hereinafter simply referred to as “transmission station”) as a transmission station. And a wireless communication apparatus 103 (hereinafter also simply referred to as “receiving station”) 103 as a receiving station.

  When the wireless communication system 100 is installed in a home or the like, the transmitting station 102 may be a video deck, a DVD player, or the like. As the receiving station 103, a television or the like can be considered. The transmitting station 102 may be built in a video deck, a DVD player, or the like, or may be connected to a video deck, a DVD player, or the like via an interface unit. The receiving station 103 may be built in a television or the like, or may be connected to the television or the like via an interface unit.

  Note that the wireless communication system 100 is not limited to the one installed in a home or the like. For example, the wireless communication system 100 may be installed in an office, and the installation location is not particularly limited.

  The transmission path from the transmission station 102 to the reception station 103 includes a “first transmission path (Directlink) 104” directly from the transmission station 102 to the reception station 103, and a radio as a relay station of the wireless communication system 100 from the transmission station 102. There is a “second transmission path 105” that reaches the receiving station 103 via a communication device (in this embodiment, the QAP 101 also serves as a relay station).

  In the present embodiment, the second transmission path 105 includes a transmission path 106 from the transmitting station 102 to the QAP 101 and a transmission path 107 from the QAP 101 to the receiving station. As described above, in the present embodiment (and the second embodiment to be described later), since QAP 101 also serves as a relay station, in the following description, transmission path 106 is described as Uplink, and transmission path 107 is described as Downlink. is doing.

  The QAP 101 controls the provision and release of a communication band in the wireless communication system 100. When transmitting data to the receiving station 103, the transmitting station 102 specifies a transmission path and requests the QAP 101 to give a necessary communication band according to the data to be transmitted. The QAP 101 assigns a communication band to the transmission station 102 if there is an available communication band corresponding to the communication band requested from the transmission station 102 in the wireless communication system 100. The transmitting station 102 transmits data to the receiving station 103 using a transmission path designated in advance in the communication band given from the QAP 101.

  The transmitting station 102 switches the first transmission path (Directlink) 104 and the second transmission path 105 according to the communication status with the receiving station 103 and transmits data to the receiving station 103. For example, when the transmission path is switched from the first transmission path (Directlink) 104 to the second transmission path 105, in order not to generate a period in which the communication band is not secured, the transmitting station 102 may change the first transmission path ( It is necessary to secure the communication band of the second transmission path 105 after switching in a state where the communication band of (Directlink) 104 is secured. This method will be described in detail later.

  For example, when the error rate exceeds a certain threshold, the transmitting station 102 determines that the communication status with the receiving station 103 is inferior, and changes the transmission path from the first transmission path (Directlink) 104 to the second transmission path 105. You may make it switch. For example, the transmitting station 102 indicates the number of data transmitted to the receiving station 103 and the number of response data returned when the receiving station 103 normally receives data transmitted from the transmitting station 102. To record. Then, the transmitting station 102 calculates the error rate from, for example, an expression “1- (number of response data / number of transmitted data)”.

  For example, the transmission station 102 may switch the transmission path from the first transmission path (Directlink) 104 to the second transmission path 105 when receiving an instruction to switch the transmission path from the reception station 103. When a DVD player that is a transmitting station 102 and a television that is a receiving station 103 are performing direct communication using the first transmission path (Directlink) 104, the error rate generally increases as the television moves away from the DVD player. As a result, the video and audio on the TV will be disturbed. At this time, for example, a television viewer instructs the television to switch the transmission path using a remote controller or the like. The television that is the receiving station 103 that has received this instruction instructs the DVD player that is the transmitting station 102 to switch the transmission path.

  Next, referring to FIG. 2 to FIG. 10, a method of switching transmission lines without impairing the real-time property of data transmission when switching the transmission line from the first transmission line (Directlink) 104 to the second transmission line 105 will be described. explain.

  FIG. 2 is a functional block diagram illustrating a schematic configuration of the transmission station 102. The transmission station 102 includes a CPU (Central Processing Unit) 201, a MEM (Memory) 202, a transmission data buffer 203, a reception data buffer 204, a wireless communication control unit 205, a modem unit 206, an antenna 207, a communication band control unit 208, and a user. A notification unit 214 is provided.

  The CPU 201 is a device that performs processing such as data input / output and command execution of the transmission station 102. The MEM 202 is a main storage device. The MEM 202 can be directly accessed by the CPU 201. The CPU 201 and the MEM 202 are connected to the wireless communication control unit 205 via the system bus.

  The transmission data buffer 203 is a device that temporarily stores data to be transmitted to the receiving station 103 or the like. The wireless communication control unit 205 controls transmission / reception of data including a beacon. The wireless communication control unit 205 is connected to the CPU 201 and the MEM 202 as described above, and is also connected to the transmission data buffer 203, the reception data buffer 204, the modem unit 206, and the communication band control unit 208.

  Data temporarily stored in the transmission data buffer 203 is transmitted to the wireless communication control unit 205. The wireless communication control unit 205 adds a relay destination address for specifying a relay station that relays data to the data received from the transmission data buffer 203 by the relay destination address setting unit 212, and receives data for specifying a receiving station. The destination address is added by the destination address setting unit 213 and transmitted to the modem unit 206. The relay destination address and the reception destination address added to the data by the wireless communication control unit 205 will be described in detail later. The modem unit 206 modulates the data received from the wireless communication control unit 205 and then transmits the modulated data to the receiving station 103 or the like via the antenna 207.

  Further, the modem unit 206 receives the modulated data transmitted from the receiving station 103 or the like via the antenna 207. The modem unit 206 demodulates the received modulated data and transmits the demodulated data to the wireless communication control unit 205.

  The wireless communication control unit 205 transmits data received from the receiving station 103 or the like to the reception data buffer 204. The reception data buffer 204 temporarily stores data received from the wireless communication control unit 205. The data temporarily stored in the reception data buffer 204 is transmitted to a processing unit (not shown) that processes the received data in accordance with a predetermined procedure.

  The communication band control unit 208 controls the communication band when the transmission path used for transmitting data to the receiving station 103 or the like is switched between the first transmission path (Directlink) 104 and the second transmission path 105. Do. The communication band control unit 208 includes a self band grant / release request unit 209, a free band confirmation unit 210, and another band grant / release request instruction unit 211.

  The own band grant / release request unit 209 requests the QAP 101 to grant a communication band according to data to be transmitted when the transmitting station 102 tries to transmit data. The QAP 101 grants a communication band if there is a free communication band corresponding to the communication band requested from the own band grant / release request unit 209 remaining in the wireless communication system 100. The transmitting station 102 transmits data using the first transmission path (Directlink) 104 or the transmission path (Uplink) 106 in the communication band given from the QAP 101.

  In addition, the own band grant / release request unit 209 requests the QAP 101 to release the communication band assigned from the QAP 101. When the communication band of the first transmission path (Directlink) 104 or the transmission path (Uplink) 106 is released, the transmission station 102 cannot transmit data using the transmission path with the communication band released.

  The free bandwidth confirmation unit 210 requests the QAP 101 to give a communication band according to data to be transmitted, and whether or not the wireless communication system 100 has a free communication bandwidth depending on whether or not the requested communication bandwidth is given from the QAP 101. Confirm whether or not. The available bandwidth confirmation unit 210 will be described in detail later.

  The other band grant / release request instructing unit 211 is, for example, a relay station so as to request that the QAP 101 grant a communication band to the transmission path (Downlink) 107 or release the communication band of the transmission path (Downlink) 107. (In the first embodiment, since the QAP 101 also serves as a relay station, the QAP 101 is instructed). For example, when the transmitting station 102 tries to transmit data to the receiving station 103 using the second transmission path 105, the relay station is instructed to request the QAP 101 to give a transmission band to the transmission path (Downlink) 107. To do.

  The user notification unit 214 notifies the user of the switching status of the communication band. For example, the user notification unit 214 notifies the user that the switching of the communication band has been completed or the cause of the switching not being performed.

  FIG. 3 is a functional block diagram illustrating a schematic configuration of a wireless communication apparatus 300 as a relay station that relays data transmitted from the transmission station 102 to the reception station 103. The relay station 300 includes a CPU 301, a MEM 302, a transmission data buffer 303, a reception data buffer 304, a wireless communication control unit 305, a modem unit 306, an antenna 307, and a communication band control unit 308. Since the description other than the communication band control unit 308 overlaps with the description of the transmitting station 102, the description thereof will not be repeated here. The communication band control unit 308 includes a self band grant / release request unit 309 and another band grant / release request control unit 310.

  When the relay station 300 tries to transmit data, the own band grant / release request unit 309 assigns the communication band according to the data to be transmitted and releases the communication band assigned from the QAP 101. To request. Since the function of own band grant / release request unit 309 is the same as the function of own band grant / release request unit 209 of transmitting station 102, the description thereof will not be repeated here.

  The other band grant / release request control unit 310, for example, sends a request to the QAP 101 to grant a communication band to the transmission line (Downlink) 107 or to release the communication standby of the transmission line (Downlink) 107. 102, when requested by the other band grant / release request instructing unit 211, the QAP 101 is requested to grant a communication band to the transmission path (Downlink) 107 or to release the communication band of the transmission path (Downlink) 107. To do.

  When a communication band is given to the transmission path (Downlink) 107 or when the communication band of the transmission path (Downlink) 107 is released, the relay station 300 (QAP 101 in the first embodiment) to the transmission station 102 Is transmitted to that effect. Note that data indicating that a communication band has been assigned to the transmission path (Downlink) 107 or that the communication band of the transmission path (Downlink) 107 has been released is not limited to data transmitted from the relay station to the transmission station 102. For example, it may be transmitted from the receiving station 103 to the transmitting station 102.

  In the first embodiment (see FIG. 1), since the QAP 101 also serves as the relay station 300, the QAP 101 performs processing of the above-described own band grant / release request unit 309 and other band grant / release request control. The processing of the unit 310 is performed in the own apparatus. In addition, although the example which does not provide the free band confirmation part 210 shown in FIG. 2 in the communication band control part 308 of the relay station 300 was shown, the free band confirmation part may be provided.

  As described above, in this embodiment, since QAP 101 also serves as relay station 300, QAP 101 includes communication band control unit 308 of relay station 300. Further, the receiving station 103 does not need any special function for the present invention, and therefore will not be described in detail here.

  4 to 7 show the communication band of the transmission path through which the transmission station 102 switches the transmission line used when transmitting data to the reception station 103 from the first transmission line (Directlink) 104 to the second transmission line 105. It is a figure showing a provision state. The assigned state represents to which transmission line the communication band is assigned.

  FIG. 4 shows a provision state before the transmission path is switched. That is, FIG. 4 shows that a communication band is given to the first transmission path (Directlink) 104. FIG. 5 and FIG. 6 are diagrams showing the provision state of the communication band of the transmission path in the middle of switching. FIG. 7 is a diagram illustrating a state after the transmission path is switched. That is, FIG. 7 shows that a communication band is given to the second transmission path 105.

  FIG. 8 is a flowchart illustrating processing executed when the transmission station 102 switches the transmission line used when transmitting data to the reception station 103 from the first transmission line (Directlink) 104 to the second transmission line 105. Of the processes executed by the transmitting station 102, the processes up to data transmission use conventional techniques and can be easily understood by those skilled in the art. Therefore, description of the processing is not described here. Further, in the first embodiment, the case where the transmission path is switched from the first transmission path (Directlink) 104 to the second transmission path 105 will be described. Therefore, at the start of the flowchart shown in FIG. (Directlink) 104 will be described assuming that a communication band has already been assigned from QAP 101 (state of FIG. 4).

  First, in step S401, the free bandwidth confirmation unit 210 determines whether or not the wireless communication system 100 has a free communication bandwidth corresponding to a communication bandwidth required for transmitting data using the transmission path (Downlink) 107. Check. Here, first, whether or not there is a free communication band corresponding to the communication band necessary for transmitting data using the transmission path (Downlink) 107 is as follows.

  When a communication band is assigned from the QAP 101 to the first transmission path (Directlink) 104 and the transmission path (Downlink) 107 (state in FIG. 5), the transmission station 102 transmits a transmission path (Uplink) 106 to which no communication band is assigned. By using the communication band of the first transmission path (Directlink) 104 to which a communication band has already been assigned as the communication band, data can be transmitted to the receiving station 103 using the second transmission path 105. is there. The use of the communication band of a certain transmission path as the communication band of another transmission path will be described in detail later.

  Here, a method in which the free bandwidth confirmation unit 210 confirms whether or not there is a free communication bandwidth in the wireless communication system 100 will be specifically described. For example, it is assumed that the amount of communication bandwidth necessary for transmitting data using the transmission path (Downlink) 107 is “α”.

  For example, the vacant bandwidth confirmation unit 210 adds the communication bandwidth amount “α” to be newly added to the communication bandwidth of the first transmission path (Directlink) 104 that has already been assigned from the QAP 101, and adds the communication bandwidth to the QAP 101. Request grant (increase). The QAP 101 gives a communication band if there is a free communication band corresponding to the communication band requested from the free band confirmation unit 210 in the wireless communication system 100, but does not give a communication band if there is not. Therefore, the free bandwidth confirmation unit 210 can confirm that the wireless communication system 100 has a free communication bandwidth of “α” remaining in the wireless communication system 100 when the communication bandwidth is given from the QAP 101. After confirming that there is a surplus communication bandwidth in the wireless communication system 100, the free bandwidth confirmation unit 210 performs a process of returning the communication bandwidth of the first transmission path (Directlink) 104 to the original communication bandwidth.

  As another method, for example, the available bandwidth confirmation unit 210 requests transmission of the communication bandwidth amount “α” to the QAP 101 assuming transmission of data for the communication bandwidth amount “α” desired to be assigned to the QAP. To do. In this case, the free bandwidth confirmation unit 210 separates the communication bandwidth “α” from the first transmission path (Directlink) 104 in addition to the communication bandwidth of the first transmission path (Directlink) 104 that has already been assigned from the QAP 101. "Is requested to QAP101. Further, as another method, the free band confirmation unit 210 further includes a communication band amount “α” in the transmission path (Uplink) 106 separately from the communication band of the first transmission path (Directlink) 104 already assigned from the QAP 101. May be requested to the QAP 101. Further, as another method, the free band confirmation unit 210 may be connected to a wireless communication apparatus other than the QAP 101 and the receiving station 103 in addition to the communication band of the first transmission path (Directlink) 104 that has already been assigned from the QAP 101. The QAP 101 may be requested to give the communication bandwidth “α” to the transmission path for transmitting data. If the communication band is given from the QAP 101, the free band confirmation unit 210 can confirm that the wireless communication system 100 has a free communication band corresponding to the communication band amount “α”. After confirming that there is a surplus communication bandwidth in the wireless communication system 100, the free bandwidth confirmation unit 210 executes processing for releasing the secured communication bandwidth “α”.

  More preferably, for example, the other band grant / release request instructing unit 211 of the transmission station 102 assigns the communication band amount “α” to the transmission path (Downlink) 107 to the other band grant / release request control unit 310 of the QAP 101. It may be requested to do. In this case, when the transmitting station 102 receives data indicating that a communication band has been granted from the other band grant / release request control unit 310, an empty communication band corresponding to the communication band requested from the wireless communication system 100 remains. Can be confirmed, and the process (step S403) for securing a communication band, which will be described later, can be omitted.

  In step S402, when it is confirmed by the free bandwidth confirmation unit 210 that there is no free communication bandwidth in the wireless communication system 100, this flowchart ends. In this case, the communication band control unit 208 of the transmitting station 102 ends the process for switching the transmission path from the first transmission path (Directlink) 104 to the second transmission path 105. Even in this case, since the transmission band is assigned to the first transmission path (Directlink) 104 (the state shown in FIG. 4), the transmission station 102 is assigned the first transmission band. The transmission of data to the receiving station 103 using the transmission path (Directlink) 104 can be continued. The processing may be started again from the beginning of FIG. 8 after a certain time. Further, the user may be notified that the transmission path has not been switched from the first transmission path (Directlink) 104 to the second transmission path 105. Also preferably, the user may be notified of a message such as “band is insufficient” or “move to a location with better radio wave condition”. On the other hand, when the free bandwidth confirmation unit 210 confirms that there is a surplus communication bandwidth in the wireless communication system 100 in step S402, the process proceeds to step S403.

  In step S403, the other band grant / release request instructing unit 211 requests the other band grant / release request control unit 310 of the QAP 101 to assign a communication band to the transmission path (Downlink) 107. In step S <b> 404, the communication band control unit 208 confirms whether data indicating that a communication band has been assigned to the transmission path (Downlink) 107 transmitted from the QAP 101 has been received.

  If it is confirmed in step S404 that data indicating that a communication band has been assigned to the transmission path (downlink) 107 transmitted from the QAP 101 has not been received, this flowchart ends. For example, when the wireless communication system 100 runs out of free communication bandwidth because the other wireless communication device has secured the communication bandwidth after the processing in step S401 is performed until the processing in step S403 is performed. Does not transmit data indicating that a communication band has been assigned to the transmission path (Downlink) 107 from the QAP 101.

  In this case, the communication band control unit 208 of the transmitting station 102 gives up switching the transmission path from the first transmission path (Directlink) 104 to the second transmission path 105. Even in this case, the transmission station 102 is in the state where the communication band is assigned to the first transmission line (Directlink) 104 (the state shown in FIG. 4). It is possible to continue transmitting data to the receiving station 103 by using the path (Directlink) 104. Also at this time, the processing may be started again from the beginning of FIG. In addition, the user notification unit 214 may notify the user notification unit that the transmission path has not been switched from the first transmission path (Directlink) 104 to the second transmission path 105. In this case, the user notification unit 214 may notify the user of a message such as “band was not granted”.

  On the other hand, when it is confirmed in step S404 that the communication band control unit 208 has received the data indicating that the communication band has been given to the transmission path (Downlink) 107 transmitted from the QAP 101, the process proceeds to step S405. It is done.

  At this time, the communication band is assigned to the transmission line in a state where the communication bands of the first transmission line (Directlink) 104 and the transmission line (Downlink) 107 are given (state in FIG. 5). In step S405, processing for using the communication band of the first transmission path (Directlink) 104 as the communication band of the transmission path (Uplink) 106 to which no communication band is given is performed. Thereby, the transmitting station 102 can transmit data to the receiving station 103 using the second transmission path 105.

  Here, a process of using the communication band of the first transmission path (Directlink) 104 as the communication band of the transmission path (Uplink) 106 to which no communication band is assigned will be described. In the specification of IEEE802.11e, the communication band control unit 208 of the transmitting station 102 requires statistical data of data transmitted using a certain transmission path in order to request that the transmission band in the QAP 101 be given a communication band. In addition to the necessary information (TSPEC), it is necessary to send to the QAP 101 information specifying the transmission path (first transmission path (Directlink) 104, transmission path (Uplink) 106, etc.) viewed from the transmitting station 102. However, the QAP 101 grants transmission time to the transmission data sequence (identified by TID) in the poll frame (for granting the communication right) transmitted to the transmitting station 102 when granting the communication band (identified by TID) ( Parameters related to (communication band) are included, but parameters that limit the transmission path are not included. Therefore, according to the specification, the transmitting station 102 can freely select a transmission path and transmit a transmission data sequence having a TID designated by a time during which transmission is permitted (communication band).

  To transmit data to the receiving station 103 using the second transmission path 105 using the communication band of the first transmission path (Directlink) 104 as the communication band of the transmission path (Uplink) 106 to which no communication band is assigned. As described above, the wireless communication control unit 205 of the transmitting station 102 changes and sets the relay destination address for specifying the relay station that relays data and the reception destination address for specifying the receiving station. It is necessary to perform processing.

  An example of a transmission data sequence and a data frame will be described with reference to FIGS. 9A to 9C. FIG. 9A is a diagram illustrating a transmission data sequence. FIG. 9B is a diagram illustrating a data frame when the transmitting station 102 transmits data to the receiving station 103 by relaying the QAP 101 (relay station). FIG. 9C is a diagram illustrating a data frame when the transmitting station 102 directly transmits data to the receiving station 103.

  As shown in FIG. 9B, the data frame is composed of a Frame_Control field 501, a Duration / ID field 502, a MAC address specifying unit (“Address1 field 503” to “Address4 field 507”), a Sequence_Control field 506, a QoS_Control field 508, and transmission data. 509 and FCS (Frame Check Sequence) field 510 and the like.

  The Frame_Control field 501 has a role of identifying the type of frame. The Duration / ID field 502 indicates the time required to transmit the transmission data sequence. The Sequence_Control field 506 includes a sequence number. A QoS_Control field 508 indicates a TID and a communication permission time or the like when the data frame is a poll frame, and indicates a communication time or a data size to be requested next when the data frame is a QoS_Null frame or the like.

  When the relay destination address setting unit 212 and the reception destination address setting unit 213 in the wireless communication control unit 205 of the transmission station 102 want to transmit “Data1” as a part of the transmission data sequence to the reception station 103 via the QAP 101. The MAC address designation part 1 (Address 1 field 503) of the data frame is set to BSSID (ID for identifying the wireless communication network formed by QAP 101) so that the relay station address is the address of QAP 101 and the destination address is the receiving station 103. Set. The relay destination address setting unit 212 and the reception destination address setting unit 213 have the MAC address specifying unit 2 (Address 2 field 504) as the MAC address of the transmitting station 102 and the MAC address specifying unit 3 (Address 3 field 505) as the MAC address of the receiving station 103. , The MAC address specifying unit 4 (Address 4 field 507) is set to none (N / A).

  On the other hand, when the relay destination address setting unit 212 and the reception destination address setting unit 213 in the wireless communication control unit 205 of the transmission station 102 want to directly transmit “Data2” as a part of the transmission data sequence to the reception station 103, The relay station address is not set, and the MAC address designation section 1 (Address 1 field 503) of the data frame is set to the MAC address of the receiving station 103 so that the receiving address is the receiving station 103. The relay destination address setting unit 212 and the destination address setting unit 213 have the MAC address specifying unit 2 (Address2 field 504) as the MAC address of the transmitting station 102, the MAC address specifying unit 3 (Address3 field 505) as the MAC address of the BSSID, MAC Address designation unit 4 (Address 4 field 507) is set to none (N / A).

  Thus, if the communication band is assigned to the first transmission path (Directlink) 104 and the transmission path (Downlink) 107, the communication band of the transmission path (Uplink) 106 to which no communication band is assigned is the first. The communication band of one transmission path (Directlink) 104 can be used, and the transmission station 102 can transmit data to the reception station 103 using the second transmission path 105.

  Similarly, if the communication band is assigned to the transmission line (Uplink) 106, the communication band of the transmission line (Uplink) 106 is set as the communication band of the first transmission line (Directlink) 104 to which no communication band is assigned. The transmitting station 102 can transmit data to the receiving station 103 using the first transmission path (Directlink) 104.

  Referring to FIG. 4 again, in step S405, the communication band control unit 208 performs a process of using the communication band of the first transmission path (Directlink) 104 for the transmission path (Uplink) 106 to which no communication band is assigned. . Thereby, the transmitting station 102 can transmit data to the receiving station 103 using the second transmission path 105. If the communication band control unit 208 stops the process of using the communication band of the first transmission path (Directlink) 104 as the communication band of the transmission path (Uplink) 106, the transmitting station 102 uses the first transmission path (Directlink) 104. Thus, data can be transmitted to the receiving station 103 at any time.

  However, although the transmission station 102 is requested to give a communication band to the first transmission path (Directlink) 104 and the communication band is given to the transmission station 102, the transmission station 102 uses the communication band as the transmission path. Since it is used as a communication band of (Uplink) 106, as a result, a time during which data is not transmitted using the first transmission path (Directlink) 104 occurs. For this reason, if the QAP 101 determines that the time has exceeded a certain time in the IEEE802.11e specification, the QAP 101 releases the communication band assigned to the first transmission path (Directlink) 104.

  Therefore, in step S405, the communication band control unit 208 of the transmission station 102 uses the first transmission path (Directlink) 104 for the transmission station 102 at the end of the time (communication band) when transmission is permitted by the QAP 101. A QoS_Null frame indicating that data has been transmitted to 103 is transmitted to the QAP 101. In this way, the QAP 101 determines that the transmitting station 102 is transmitting data to the receiving station 103 using the first transmission path (Directlink) 104, and releases the communication band of the first transmission path (Directlink) 104. do not do.

  Similarly, when the communication band of the transmission line (Uplink) 106 is used as the communication band of the first transmission line (Directlink) 104 to which no communication band is given, the communication band control unit 208 of the transmission station 102 At the end of the time (communication band) permitted for transmission by the QAP 101, a QoS_Null frame indicating that data has been transmitted using the transmission path (Uplink) 106 is transmitted to the QAP 101. By doing so, the QAP 101 determines that the transmitting station 102 is transmitting data using the transmission path (Uplink) 106 and does not release the communication band of the transmission path (Uplink) 106.

  FIG. 10 is a diagram illustrating a state in which the transmitting station 102 transmits data to the receiving station 103 via the QAP 101 by using the communication band of the first transmission path (Directlink) 104. It is assumed that a communication band has already been assigned from the QAP 101 to the first transmission path (Directlink) 104. The transmitting station 102 can transmit data to the receiving station 103 using the first transmission path (Directlink) 104 in the communication band given from the QAP 101.

  When the wireless communication control unit 205 of the transmitting station 102 uses the communication band of the first transmission path (Directlink) 104 as the communication band of the transmission path (Uplink) 106 to which no communication band is assigned, the data frame as described above. The MAC address designation part (“Address 1 field 503” to “Address 4 field 507”) in the MAC header is changed and set. As a result, the transmitting station 102 can transmit data to the receiving station 103 using the second transmission path 105. At this time, the QAP 101 that has received the data transmitted from the transmitting station 102 has the destination of the data described as the receiving station 103 in the address designation section (Address 3) in the MAC header. Forward to.

  The communication band control unit 208 of the transmission station 102, at the end of the time (communication band) in which transmission is permitted by the QAP 101, prevents the QAP 101 from releasing the communication band of the first transmission path (Directlink) 104. A QoS_Null frame indicating that data has been transmitted to the receiving station 103 using the first transmission path (Directlink) 104 is transmitted to the QAP 101.

  Note that the use of a communication band for a certain transmission line as a communication band for another transmission path is not only when the transmission line is switched from the first transmission line (Directlink) 104 to the second transmission line 105 but also the first transmission line. This is also useful when both the (Directlink) 104 and the second transmission path 105 need to be given communication bands. This is because if the communication band of one of the first transmission path (Directlink) 104 and the transmission path (Uplink) 106 and the communication band of the transmission path (Downlink) 107 are given, the first transmission path (Directlink) This is because the same effect as when the communication bands 104 and the second transmission path 105 are both provided can be obtained with a small amount of communication band.

  Refer to FIG. 4 again. By each process up to step S405, the transmission path is switched from the first transmission path (Directlink) 104 to the second transmission path 105 without causing a period in which no communication band is given and without impairing the real-time property of data transmission. Can do. However, if the wireless communication system 100 has a free communication band that can give a communication band to the transmission line (Uplink) 106, the QAP 101 is requested to give a communication band to the transmission line (Uplink) 106. It is preferable to do. This is because the communication band control unit 208 of the transmission station 102 continues the process of using the communication band of a certain transmission path as the communication band of another transmission path by giving the communication band of the second transmission path 105. This is because it is no longer necessary.

  In step S406, the own band grant / release request unit 209 requests the QAP 101 to grant a communication band to the transmission path (Uplink) 106. The QAP 101 grants a communication band if there is a free communication band corresponding to the communication band requested from the own band grant / release request unit 209 remaining in the wireless communication system 100. At this time, the transmission band is given a communication band as shown in FIG.

  In step S407, when the own band grant / release request unit 209 determines that the communication band is not given from the QAP 101, the process returns to step S405. On the other hand, when the own band grant / release request unit 209 determines in step S407 that the communication band has been given from the QAP 101, the process proceeds to step S408. In step S408, the own band grant / release request unit 209 requests the QAP 101 to release the communication band of the first transmission path (Directlink) 104. At this time, the transmission band is given a communication band as shown in FIG. Thereafter, this flowchart ends. At this time, the user notification unit 214 may notify the user that the transmission path is switched from the first transmission path (Directlink) 104 to the second transmission path 105.

  In step S408, an example is shown in which the own band grant / release request unit 209 requests the QAP 101 to release the communication band of the first transmission path (Directlink) 104. May not require the QAP 101 to release the communication band of the first transmission path (Directlink) 104.

  In this embodiment, radio communication system 100 has only one transmitting station 102, and the transmission path from transmitting station 102 to receiving station 103 is a first transmission path (Directlink) and a second transmission path 105. An example in which the transmission station 102 switches the transmission path when there are two types and an example in which the bandwidth of the quantity transmission path can be secured with a small amount of bandwidth are shown. However, the system to which the present invention is applied is not limited to this. For example, the present invention is applicable even when the wireless communication system 100 includes a plurality of wireless communication apparatuses and the transmission station can select a plurality of transmission paths of three or more. In this case, for example, the transmission station may switch the transmission path, or the transmission station may secure the bands of the plurality of transmission paths with a small amount of bandwidth.

  According to the first embodiment, the transmission station 102 is assigned to the first transmission path (Directlink) 104 when the transmission path is switched from the first transmission path (Directlink) 104 to the second transmission path 105. By using the communication band as the communication band of the transmission path (Uplink) 106, data can be transmitted to the receiving station 103 using the second transmission path 105 after switching. Further, since the transmitting station 102 only uses the communication band assigned to the first transmission path (Directlink) 104 for the transmission path (Uplink) 106 after switching, the first transmission path (Directlink) before switching is used. ) 104 can be used to transmit data to the receiving station 103. That is, the transmitting station 102 can return to the communication state before the switching at any time during the transmission path switching process.

  When the transmission station 102 switches the transmission path from the first transmission path (Directlink) 104 to the second transmission path 105, the switching does not cause a period in which no communication band is given to the transmission path. Therefore, it can be prevented that the real-time property of data transmission is impaired.

  Further, the transmitting station 102 confirms whether or not there is a free communication band in the wireless communication system 100 before the transmitting station 102 switches the transmission path from the first transmission path (Directlink) 104 to the second transmission path 105. It is possible to predict whether or not switching from the first transmission path (Directlink) 104 to the second transmission path 105 is possible.

  When the transmitting station 102 confirms that the available communication band is insufficient, the transmitting station 102 switches the transmission path from the first transmission path (Directlink) 104 to the second transmission path 105. Can be canceled.

  Further, when the transmission station 102 uses the communication band assigned to the first transmission path (Directlink) 104 as the communication band of the transmission path (Uplink) 106, the transmission station 102 at the end of the time when transmission is permitted (communication band), By transmitting to the QAP 101 a QoS_Null frame indicating that data has been transmitted to the receiving station 103 using one transmission path (Directlink) 104, the communication band assigned to the first transmission path (Directlink) 104 is released by the QAP101. Can be prevented. Further, the transmitting station 102 can notify the user of the status of processing for switching the transmission path from the first transmission path (Directlink) 104 to the second transmission path 105.

  In addition, the transmission station 102 uses the communication band of the first transmission path (Directlink) 104 or the transmission path 106 as the communication band of other transmission paths, so that the first transmission path (Directlink) 104 and the second transmission path 105 are used. Therefore, it is possible to reduce the communication band necessary for securing both communication bands. Therefore, the radio communication system 100 can operate a communication band with high efficiency.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, differences from the first embodiment will be mainly described. Specifically, in the first embodiment, an example in which the transmission path is switched from the first transmission path (Directlink) 104 to the second transmission path 105 and data is transmitted from the transmission station 102 to the reception station 103 is described. It was. On the other hand, in this embodiment, an example in which the transmission path is switched from the second transmission path 105 to the first transmission path (Directlink) 104 and data is transmitted from the transmission station 102 to the reception station 103 will be described.

  Note that the hardware configuration of the radio communication system according to the present embodiment is the same as the hardware configuration of the radio communication system according to the first embodiment, except as described below. Their functions are the same. Therefore, description thereof will not be repeated here.

  Also in this embodiment, the QAP 101 performs a function as a relay station. The second transmission path 105 includes a transmission path 106 from the transmitting station 102 to the QAP 101 and a transmission path 107 from the QAP 101 to the receiving station.

  FIG. 11 and FIG. 12 are diagrams each showing a communication band assignment state of a transmission path in the middle of switching in the present embodiment.

  FIG. 13 is a flowchart illustrating processing executed when the transmission station 102 switches the transmission path used when transmitting data to the reception station 103 from the second transmission path 105 to the first transmission path (Directlink) 104. As a result of these processes, the transmission band communication band shifts from the state shown in FIG. 7 to the state shown in FIG. Note that, as in the first embodiment described above, the processing up to data transmission among the processing executed by the transmitting station 102 is realized by the conventional technology, and this technology can be easily understood by those skilled in the art. is there. Therefore, description thereof will not be repeated here. In this embodiment, a case where the transmission path is switched from the second transmission path 105 to the first transmission path (Directlink) 104 will be described. Therefore, at the start of the flowchart shown in FIG. 13, it is assumed that the communication band has already been assigned from the QAP 101 to the transmission path (Uplink) 106 and the transmission path (Downlink) 107 (state shown in FIG. 7).

  The transmitting station 102 switches the first transmission path (Directlink) 104 and the second transmission path 105 according to the communication status with the receiving station 103 and transmits data to the receiving station 103. When the transmitting station 102 switches the transmission path from the second transmission path 105 to the first transmission path (Directlink) 104, a period in which a communication band is not given occurs so that the real-time property of data transmission is not impaired. In addition, the communication band control unit 208 requests the QAP 101 to give the communication band to the first transmission path (Directlink) 104 after switching in a state where the communication band is given to the second transmission path 105 before switching. There is a need.

  Similar to the first embodiment, the transmitting station 102 determines that the communication status with the receiving station 103 is poor when, for example, the error rate exceeds a certain threshold, and changes the transmission path from the second transmission path 105. You may make it switch to the 1st transmission line (Directlink) 104. Also, when a TV viewer who is the receiving station 103 instructs the television to switch the transmission path using a remote controller or the like, the transmitting station 102 determines that the transmission path is based on the switching instruction relayed by the QAP 101. May be switched from the second transmission path 105 to the first transmission path (Directlink) 104.

  Referring to FIG. 13, first, in step S <b> 701, the free bandwidth confirmation unit 210 determines that a free communication bandwidth corresponding to a communication bandwidth necessary for transmitting data using the first transmission path (Directlink) 104 is wireless communication. It is confirmed whether or not there is a surplus in the system 100.

  Here, an outline of a method in which the free bandwidth confirmation unit 210 confirms whether or not there is a free communication bandwidth in the wireless communication system 100 will be described. For example, it is assumed that the amount of communication band necessary for transmitting data using the first transmission path (Directlink) 104 is “β”. The free bandwidth confirmation unit 210 confirms whether or not there is a free communication bandwidth in the wireless communication system 100 by replacing the communication bandwidth amount α with β using the method described in the first embodiment.

  More preferably, for example, the own band grant / release request unit 209 of the transmitting station 102 requests the QAP 101 to grant the communication bandwidth “β” to the first transmission path (Directlink) 104. It may be. In this case, when a communication band is given from the QAP 101, the transmitting station 102 can confirm that there is a surplus communication band corresponding to the communication band requested from the wireless communication system 100, and a communication band described later. Can be omitted (step S703).

  In step S702, when the free bandwidth confirmation unit 210 confirms that the wireless communication system 100 has a free communication bandwidth, the process proceeds to step S703. In step S <b> 703, the own band grant / release request unit 209 requests the QAP 101 to grant a communication band to the first transmission path (Directlink) 104. The QAP 101 grants a communication band if the free communication band corresponding to the communication band requested from the own band grant / release request unit 209 is left in the wireless communication system 100 (state shown in FIG. 6). In this case, between the time when the process in step S701 is performed and the time when the process in step S703 is performed, for example, another wireless communication device secures a communication band, so that the wireless communication system 100 has no free communication band. In some cases, the QAP 101 cannot give a communication band.

  In step S704, when the own band grant / release request unit 209 determines that the communication band is not given from the QAP 101, this flowchart ends. In this case, the communication band control unit 208 of the transmitting station 102 gives up switching the transmission path from the second transmission path 105 to the first transmission path (Directlink) 104. Even in this case, since the state of the transmission line is a state where the communication band is given to the second transmission line 105 (the state shown in FIG. 7), the transmitting station 102 uses the second transmission line 105. Thus, it is possible to continue transmitting data to the receiving station 103. In step S704, when the own band grant / release request unit 209 determines that the communication band is not given from the QAP 101, the process may be advanced to step S706 described later. Further, the processing may be started again from the beginning of FIG. 13 after a certain time. In addition, the user notification unit 214 may notify the user that the transmission path has not been switched from the second transmission path 105 to the first transmission path (Directlink) 104. Preferably, the user notification unit 214 may notify the user of a message such as “band is insufficient” or “move to a place with better radio wave conditions”.

  On the other hand, if the own band grant / release request unit 209 determines in step S704 that the communication band has been granted from the QAP 101, the process proceeds to step S705. In step S <b> 705, the own band grant / release request unit 209 requests the QAP 101 to release the communication band of the transmission path (Uplink) 106. Further, the other band grant / release request instruction unit 211 requests the QAP 101 to release the communication band of the transmission path (Downlink) 107. The other band grant / release request control unit 310 of the QAP 101 performs processing for releasing the communication band of the transmission line (Uplink) 106 and the transmission line (Downlink) 107. At this point, the transmission band communication band is given as shown in FIG. 4, and this flowchart ends.

  In step S702, when the free bandwidth confirmation unit 210 confirms that there is no free communication bandwidth remaining in the wireless communication system 10, the process proceeds to step S706. At this time, the communication band of the transmission line (Uplink) 106 and the transmission line (Downlink) 107 is provided (the state shown in FIG. 7).

  In step S706, processing for using the communication band of the transmission line (Uplink) 106 as the communication band of the first transmission line (Directlink) 104 to which no communication band is given is performed. Accordingly, the transmitting station 102 can transmit data to the receiving station 103 using the first transmission path (Directlink) 104. In step S706, the communication band control unit 208 of the transmitting station 102 uses the transmission path (Uplink) 106 to connect the receiving station 103 to the receiving station 103 at the end of the time when transmission is permitted by the QAP 101 (communication band). A QoS_Null frame indicating that data has been transmitted is transmitted to the QAP 101. By doing so, the QAP 101 determines that the transmitting station 102 is transmitting data to the receiving station 103 using the transmission path (Uplink) 106 and does not release the communication band of the transmission path (Uplink) 106.

  By the processing up to step S706, the transmission path is switched from the second transmission path 105 to the first transmission path (Directlink) 104 without causing a period in which no communication band is given and without impairing the real-time property of data transmission. It is done. However, if the wireless communication system 100 has a free communication band that can give a communication band to the first transmission path (Directlink) 104, the communication band is given to the first transmission path (Directlink) 104. Is preferably requested from the QAP 101. Because the communication band of the first transmission path (Directlink) 104 is given, the communication band control unit 208 of the transmission station 102 uses the communication band of a certain transmission path as the communication band of another transmission path described above. This is because it is not necessary to continue processing.

  In step S707, the other band grant / release request instruction unit 211 requests the other band grant / release request control unit 310 of the QAP 101 to release the communication band of the transmission path (Downlink) 107. If the communication band of the transmission path (Downlink) 107 has already been released, the processing in step S707 is not performed. In step S707, when the communication band control unit 208 receives data indicating that the communication band of the transmission path (Downlink) 107 has been released from the QAP 101, the process proceeds to step S708. At this point, the transmission path communication band is given as shown in FIG.

  In step S708, the own band grant / release request unit 209 requests the QAP 101 to grant the communication band to the first transmission path (Directlink) 104. The QAP 101 assigns a communication band to the first transmission path (Directlink) 104 if an empty communication band corresponding to the communication band requested by the own band grant / release request unit 209 is left in the wireless communication system 100. In step S706, since the communication band of the transmission path (Downlink) 107 is released, there is a high possibility that an empty communication band is left in the wireless communication system 100. In step S708, the communication band is easily given by the QAP 101.

  In step S709, when the own band grant / release request unit 209 determines that the communication band is not given from the QAP 101, the process returns to step S706. On the other hand, when the own band grant / release request unit 209 determines in step S709 that the communication band has been granted by the QAP 101, the process proceeds to step S710. At this point, the transmission band is given the communication band as shown in FIG. In step S <b> 710, the own band grant / release request unit 209 requests to release the communication band of the transmission line (Uplink) 106 that has become unnecessary. At this point, the transmission path communication band is given as shown in FIG. 4, and this flowchart ends. At this time, the user notification unit 214 may notify the user that the transmission path is switched from the second transmission path 105 to the first transmission path (Directlink) 104.

  In the first and second embodiments described above, since the available communication band of the wireless communication system 100 is insufficient, when the communication band of the transmission path after switching is not assigned, it is already assigned from the QAP 101. The communication band of the transmission path before switching may be released, and data may be transmitted using EDCA on the transmission path before switching. In this way, since the shortage of the free communication band of the wireless communication system 100 is resolved, it becomes easy to secure the communication band after switching.

  In the first and second embodiments described above, the example in which the QAP 101 also serves as the relay station 300 is shown. However, even if another wireless communication device operates as the relay station 300, Good.

  Further, in the first and second embodiments, the communication band control unit 208 of the transmission station 102 and the communication band control unit 308 of the relay station 300 provide a request for granting / releasing transmission band, a request instruction, and a free space. Although the communication band is confirmed, a wireless communication apparatus other than the transmitting station 102 and the relay station 300 may perform the process.

  According to the second embodiment, when the transmitting station 102 switches the transmission path from the second transmission path 105 to the first transmission path (Directlink) 104, the communication band given to the transmission path (Uplink) 106 is changed. By using the communication band of the first transmission path (Directlink) 104, data can be transmitted to the receiving station 103 using the first transmission path (Directlink) 104 after switching. Further, since the transmitting station 102 only uses the communication band given to the transmission path (Uplink) 106 as the communication band of the first transmission path (Directlink) 104 after switching, the transmission path ( Data can be transmitted to the receiving station 103 by using the (Uplink) 106 and the transmission path (Downlink) 107. That is, radio communication system 100 according to the present embodiment can always return to the communication state before switching during transmission path switching processing.

  In addition, when the transmission station 102 executes a process of switching the transmission path from the second transmission path 105 to the first transmission path (Directlink) 104, the process causes a period in which no communication band is given to the transmission path. I will not let you. For this reason, it can prevent impairing the real-time property of data transmission.

  In addition, before the transmitting station 102 switches from the second transmission path 105 to the first transmission path (Directlink) 104, the free bandwidth confirmation unit 210 confirms whether or not the wireless communication system 100 has a free communication bandwidth. Therefore, the transmitting station 102 can predict whether or not the second transmission path 105 can be switched to the first transmission path (Directlink) 104. When the available bandwidth confirmation unit 210 confirms that the available bandwidth is insufficient, the transmitting station 102 can stop switching the transmission path from the second transmission path 105 to the first transmission path (Directlink) 104.

  When the communication band given to the transmission line (Uplink) 106 is used as the communication band of the first transmission line (Directlink) 104, the transmission line (Uplink) is added at the end of the time (communication band) when transmission is permitted. By transmitting a QoS_Null frame indicating that data has been transmitted to the receiving station 103 using 106 to the QAP 101, it is possible to prevent the communication band assigned to the transmission path (Uplink) 106 from being released by the QAP 101. it can.

  In addition, the transmission station 102 can notify the user of the status of the process of switching the transmission path from the second transmission path 105 to the first transmission path (Directlink) 104 according to the display of messages and other modes.

  Note that the object of the present invention is achieved by hardware by a combination of circuit elements and other components that realize each process, but the object can also be achieved by cooperation of software and hardware. That is, a storage medium (main memory or external storage) storing software program codes for realizing the functions of the first embodiment and the second embodiment described above is supplied to a wireless communication system or a wireless communication device. This can also be achieved by the computer (CPU or MPU) of the wireless communication system or wireless communication device reading and executing the program code stored in the storage medium.

  Thus, a computer system 1400 that functions as a wireless communication apparatus according to this embodiment will be described. FIG. 14 is a block diagram showing a hardware configuration of computer system 1400.

  The computer system 1400 includes a CPU 1410 that is connected to each other via a data bus, a mouse 1420 and a keyboard 1430 that receive input of instructions from a user of the computer system 1400, and input data or data generated by execution of a program by the CPU 1410. A hard disk 1450 capable of storing a large amount of data, a CD-ROM (Compact Disk-Read Only Memory) driving device 1460, a monitor 1480, and a communication IF (Interface) 1490. . A CD-ROM 1462 is attached to the CD-ROM drive 1460.

  The processing in the computer system 1400 is realized by each hardware and software (program code) executed by the CPU 1410. Such software is stored in the RAM 1440 or the hard disk 1450 in advance. The software may be stored in a CD-ROM 1462 or other data recording medium and distributed as a program product. Alternatively, the software may be provided as a program product that can be downloaded by an information provider connected to the Internet or other communication line. Such software is temporarily stored in the hard disk 1450 after being read from the data recording medium by the CD-ROM drive 1460 or other reading device, or after being downloaded via the communication IF 1490. The software is read from the hard disk 1450 into the RAM 1440 as an executable format and is executed by the CPU 1410.

  Each hardware constituting the computer system 1400 shown in FIG. 14 is general. Therefore, it can be said that the most essential part of the present invention is software stored in the RAM 1440, the hard disk 1450, the CD-ROM 1462 or other data recording medium, or downloadable via a network. Since the operation of each hardware of computer system 1400 is well known, detailed description will not be repeated.

  In this case, the software program code itself read from the storage medium realizes the functions of the first and second embodiments described above, and the storage medium storing the program code constitutes the present invention. It will be.

  The storage medium for supplying the program code may be a semiconductor memory or other medium that carries a fixed program. Such media include a hard disk 1450 and a CD-ROM 1462, as well as a flexible disk, cassette tape, magneto-optical disk (MO (Magnetic Optical Disc), MD (Mini Disc), DVD), IC card (memory card). ), Optical card, mask ROM, EPROM (Erasable programmable ROM), EEPROM (Electrically Erasable and Programmable ROM), flash ROM, and the like.

  Further, not only the functions in the embodiments are realized by executing the program code read by the computer, but an OS (Operating System) operating on the computer based on the instruction of the program code is actually used. The function of each embodiment may be realized by executing a part or all of the process and executing the process.

  Further, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. The CPU or the like provided in the board or the function expansion unit may perform part or all of the actual processing, and the functions in the above-described embodiments may be realized by the processing.

  When the present invention is realized by the above-described storage medium, the storage medium stores program codes corresponding to the processes included in the above-described flowcharts (see FIGS. 4 and 7).

  As described above, according to the above-described embodiment, a communication band already assigned to a certain transmission path can be used as a communication band of another transmission path to which a communication band has not yet been assigned. Also, since the communication band already assigned to a certain transmission path is only used as the communication band of another transmission path that has not yet been assigned a communication band, if the use is stopped, the original transmission path is restored. Can be used immediately as a communication band. In addition, by using the assigned communication band as another communication band, a communication band that is originally required for another transmission path becomes unnecessary, so that an efficient communication band can be provided as a wireless communication system. it can.

  In addition, a transmission path used for transmitting data to another wireless communication apparatus can be switched between the first transmission path and the second transmission path. Furthermore, when switching between the first transmission path and the second transmission path, by using the communication band given to the transmission path before switching by the wireless communication control unit as the communication band of the transmission path after switching, Data can be transmitted to other wireless communication devices using the transmission path. In addition, since the communication band assigned to the transmission path before switching remains secured, data transmission is continued using the transmission path before switching even during the process of securing the bandwidth on the transmission path after switching. be able to. For this reason, since the data transmission interruption time does not occur in the process of switching the transmission path, it is possible to eliminate the possibility that the data transmission interruption causes a delay time and exceeds the DelayBound value allowed for transmission. That is, it is possible to prevent the real-time property of data transmission from being impaired.

  Further, since the communication bands on the first transmission path and the third transmission path are always given, if the communication band on the first transmission path is used as it is, the first transmission path is used to another wireless communication apparatus. Data transmission is possible. Further, by using the communication band on the first transmission path as the communication band on the fourth transmission path to the relay station in the second transmission path, the second transmission path is used together with the communication band on the third transmission path. Data transmission to other wireless communication devices. For this reason, no interruption time of data transmission occurs in the process of switching the transmission path, so that it is possible to eliminate the possibility that a delay time occurs due to the interruption of data transmission and exceeds the DelayBound value allowed for transmission. That is, it is possible to prevent the real-time property of data transmission from being impaired.

  In addition, since the communication band on the fourth transmission path is always given, by using this communication band as the communication band on the first transmission path, to the other wireless communication device using the first transmission path. Data transmission is possible. For this reason, no interruption time of data transmission occurs in the process of switching the transmission path, so that it is possible to eliminate the possibility that a delay time occurs due to the interruption of data transmission and exceeds the DelayBound value allowed for transmission. That is, it is possible to prevent the real-time property of data transmission from being impaired.

  When switching from the first transmission path to the second transmission path, the communication band assigned to the first transmission path before switching is used as the communication band of the second transmission path after switching, and the second transmission path is used. Data can be transmitted to other wireless communication devices.

  Further, when switching from the second transmission path to the first transmission path, the communication band assigned to the second transmission path before switching is used as the communication band of the first transmission path after switching, and the first transmission path is used. Data can be transmitted to other wireless communication devices.

  In addition, for example, the user of the wireless communication apparatus can be notified of the status of processing for switching the transmission path between the first transmission path and the second transmission path. For example, by notifying that the transmission path switching process has been completed, the user knows that the transmission path switching process has now been completed. Also, for example, the user can know what problem has occurred by performing a notification that the transmission path switching process has been canceled due to a lack of communication bandwidth. Further, for example, by making a notification that prompts the user to move to a place with better radio wave conditions, the user can obtain information such as what to do.

  Further, the wireless communication apparatus can request the relay station to request the central control station to give a communication band for the relay station to communicate, and secure the communication band as a whole wireless communication system. It becomes possible to increase the flexibility.

  In addition, the wireless communication apparatus can request the relay station to request the central control station to release a communication band for the relay station to communicate with, thereby releasing the communication band of the entire wireless communication system. It becomes possible to increase the flexibility. In combination with the above invention, for example, when there is not enough room in the communication band in the wireless communication system, when switching the transmission path, the communication band that is unnecessary after switching the transmission path is released first, so that it is free. The amount of bandwidth increases, and it becomes easy to secure the communication bandwidth required after switching the transmission path.

  In addition, it is predicted whether or not the first transmission path and the second transmission path can be switched by checking whether or not there is a free communication band before switching between the first transmission path and the second transmission path. It is possible to make use of the information for requesting the provision and release of a new communication band. For example, it is possible to predict the success or failure of switching of the communication band by acquiring the free band amount in advance before switching the communication band. In addition, it is possible to reduce the possibility that the communication band cannot be secured due to insufficient communication band.

  Moreover, it is possible to avoid the failure itself of the process of switching the transmission path between the first transmission path and the second transmission path due to the lack of available bandwidth. In addition, it is possible to avoid a loss of time from when the switching of the communication band fails until returning to the original state before switching.

  Further, it is possible to prevent the communication band given to the transmission path before switching from being released by the central control station.

  In addition, another wireless communication device can instruct the central control station to request the central control station to assign a communication band to a transmission path for transmitting data by the relay station, and the communication band can be assigned to the central control station. Request flexibility can be increased.

  In addition, another radio communication device can instruct the central control station to release the communication band of the transmission path for transmitting data from the relay station, and the communication band for the central control station can be released. Request flexibility can be increased.

  Further, according to the wireless communication system according to the present embodiment, it is possible to switch the transmission path without impairing the real-time property of data transmission.

  According to the program product according to the present embodiment, a computer that executes the program product can switch the transmission path without impairing the real-time property of data transmission.

  According to the storage medium according to the present embodiment, the computer switches the transmission path without impairing the real-time property of data transmission by mounting the storage medium on the computer and executing the stored program product. be able to.

  It should be understood that the embodiment disclosed this time is an example in all respects, and is not limited to be implemented only in IEEE 802.11e. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention relates to an information processing device having a communication function such as a mobile phone, a notebook type PC (Personal Computer), such as a VTR (Video Tape Recorder), a DVD player or other video recording / reproducing device, a television receiving device or the like. It can be applied to a video display device.

Claims (23)

A wireless communication device,
A transmission / reception unit (206) for transmitting / receiving data to / from other wireless communication devices via a plurality of transmission paths;
A communication band that controls the communication band so that the communication band assigned to a certain transmission line from the central control station that assigns and releases the communication band is used as the communication band of another transmission line that is not assigned a communication band. A control unit (208),
The transmission path includes a first transmission path that directly transmits data to the other wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station,
The communication band control unit requests the central control station to give a communication band to a third transmission line from the relay station to the other wireless communication device in the second transmission line. A wireless communication apparatus including an other band grant request instructing unit (211) that instructs the relay station. The communication bandwidth control unit may include other bandwidth release request instruction unit (211) instructing the relay station to request opening the communication band of the third transmission path to the central control station, wherein Item 2. The wireless communication device according to Item 1 . A wireless communication device,
A transmission / reception unit (206) for transmitting / receiving data to / from other wireless communication devices via a plurality of transmission paths;
A communication band that controls the communication band so that the communication band assigned to a certain transmission line from the central control station that assigns and releases the communication band is used as the communication band of another transmission line that is not assigned a communication band. A control unit (208),
The transmission path includes a first transmission path that directly transmits data to the other wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station,
A wireless communication control unit (205) for switching a transmission line used for transmitting data to the other wireless communication apparatus between the first transmission line and the second transmission line;
When the wireless communication control unit switches the transmission path from the first transmission path to the second transmission path, in the switching process, the communication band on the first transmission path, and the second transmission path After passing through the state where the communication band on the third transmission path from the relay station to the other wireless communication device is given, the state where all the communication bands of the first transmission path and the second transmission path are given A wireless communication device that passes. A wireless communication device,
A transmission / reception unit (206) for transmitting / receiving data to / from other wireless communication devices via a plurality of transmission paths;
A communication band that controls the communication band so that the communication band assigned to a certain transmission line from the central control station that assigns and releases the communication band is used as the communication band of another transmission line that is not assigned a communication band. A control unit (208),
The transmission path includes a first transmission path that directly transmits data to the other wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station,
A wireless communication control unit (205) for switching a transmission line used for transmitting data to the other wireless communication apparatus between the first transmission line and the second transmission line;
When the wireless communication control unit switches the transmission path from the second transmission path to the first transmission path, in the switching process, on the fourth transmission path from the own device of the second transmission path to the relay station. The wireless communication device passes through the state where the communication bands of the first transmission line and the fourth transmission line are assigned after passing through the state where only the communication band is assigned. A wireless communication device,
A transmission / reception unit (206) for transmitting / receiving data to / from other wireless communication devices via a plurality of transmission paths;
A communication band that controls the communication band so that the communication band assigned to a certain transmission line from the central control station that assigns and releases the communication band is used as the communication band of another transmission line that is not assigned a communication band. A control unit (208),
The transmission path includes a first transmission path that directly transmits data to the other wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station,
A wireless communication control unit (205) for switching a transmission line used for transmitting data to the other wireless communication apparatus between the first transmission line and the second transmission line;
The communication band control unit uses the transmission path before switching when the transmission path used for transmitting data to the other wireless communication apparatus is switched between the first transmission path and the second transmission path. A wireless communication device that executes control to transmit data indicating that data is being transmitted to the other wireless communication device to the central control station. A wireless communication device,
A transmission / reception unit (206) for transmitting / receiving data to / from other wireless communication devices via a plurality of transmission paths;
A communication band that controls the communication band so that the communication band assigned to a certain transmission line from the central control station that assigns and releases the communication band is used as the communication band of another transmission line that is not assigned a communication band. A control unit (208),
The transmission path includes a first transmission path that directly transmits data to the other wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station,
A wireless communication control unit (205) for switching a transmission line used for transmitting data to the other wireless communication apparatus between the first transmission line and the second transmission line;
The communication band control unit requests the central control station to provide a communication band for transmitting data to the other wireless communication device, and depending on whether a communication band is provided from the central control station, A free bandwidth confirmation unit (210) for confirming whether or not there is a free communication bandwidth in the wireless communication system to which the device belongs,
The wireless communication control unit is a wireless communication device that stops switching between the first transmission path and the second transmission path when the empty bandwidth confirmation unit confirms that the free bandwidth is insufficient . A wireless communication device as a relay station that receives data from a transmission-side wireless communication device via a transmission line and transmits the received data to the reception-side wireless communication device via a transmission line,
The transmission path includes a first transmission path that directly transmits data from the transmitting-side wireless communication apparatus to the receiving-side wireless communication apparatus, and the transmitting-side wireless communication apparatus via the relay station to the receiving-side wireless communication apparatus. A second transmission path for transmitting data to the wireless communication device,
Requesting the central control station that assigns and releases the communication band to assign the communication band to the third transmission path from the relay station to the wireless communication device on the receiving side of the second transmission path. When requested by another wireless communication device, the other band grant request control unit (310) that requests the central control station to grant the communication band of the third transmission path,
A wireless communication apparatus comprising: an added data transmission control unit (305) that controls transmission of data indicating that a communication band has been assigned to the third transmission path. When another wireless communication apparatus instructs the central control station to release the communication band of the third transmission path, the central control station sets the communication band of the third transmission path to Other band release request control unit (310) that requests release,
The wireless communication apparatus according to claim 7 , further comprising an open data transmission control unit (305) that controls transmission of data indicating that a communication band of the third transmission path has been released. A wireless communication method for transmitting and receiving data between a first wireless communication device and a second wireless communication device via a plurality of transmission paths,
Detecting a communication band assigned to a transmission path among the plurality of transmission paths from a central control station that assigns and releases a communication band; and
A communication band control step for controlling the detected communication band so as to be used as a communication band of another transmission path to which no communication band is given,
The plurality of transmission paths include a first transmission path for directly transmitting data from the first wireless communication apparatus to the second wireless communication apparatus, and a first transmission path from the first wireless communication apparatus to the second wireless communication apparatus. A second transmission path for transmitting data via the relay station,
Instructs the central control station to request the relay station to give a communication band to a third transmission path from the relay station to the second wireless communication device in the second transmission path. A wireless communication method, further comprising an other band grant request instruction step. The radio communication method according to claim 9 , further comprising: another band release request instruction step for instructing the relay station to request the central control station to release the communication band of the third transmission path. A wireless communication method for transmitting and receiving data between a first wireless communication device and a second wireless communication device via a plurality of transmission paths,
Detecting a communication band assigned to a transmission path among the plurality of transmission paths from a central control station that assigns and releases a communication band; and
A communication band control step for controlling the detected communication band so as to be used as a communication band of another transmission path to which no communication band is given,
The plurality of transmission paths include a first transmission path for directly transmitting data from the first wireless communication apparatus to the second wireless communication apparatus, and a first transmission path from the first wireless communication apparatus to the second wireless communication apparatus. A second transmission path for transmitting data via the relay station,
A wireless communication control step of switching a transmission path used for transmitting data to the second wireless communication apparatus between the first transmission path and the second transmission path;
When the wireless communication control step switches the transmission path from the first transmission path to the second transmission path, in the process of switching, the communication band on the first transmission path and the relay of the second transmission paths After passing through the state where the communication band on the third transmission path from the station to the second wireless communication device is given, the state where all the communication bands on the first transmission line and the second transmission path are given A wireless communication method that elapses. A wireless communication method for transmitting and receiving data between a first wireless communication device and a second wireless communication device via a plurality of transmission paths,
Detecting a communication band assigned to a transmission path among the plurality of transmission paths from a central control station that assigns and releases a communication band; and
A communication band control step for controlling the detected communication band so as to be used as a communication band of another transmission path to which no communication band is given,
The plurality of transmission paths include a first transmission path for directly transmitting data from the first wireless communication apparatus to the second wireless communication apparatus, and a first transmission path from the first wireless communication apparatus to the second wireless communication apparatus. A second transmission path for transmitting data via the relay station,
A wireless communication control step of switching a transmission path used for transmitting data to the second wireless communication apparatus between the first transmission path and the second transmission path;
When the wireless communication control step switches the transmission path from the second transmission path to the first transmission path, in the switching process, from the first wireless communication device of the second transmission path to the relay station After passing through the state where only the communication band on the fourth transmission path is assigned, the wireless communication method passes the state where the communication band on the first transmission path and the fourth transmission path is assigned. A wireless communication method for transmitting and receiving data between a first wireless communication device and a second wireless communication device via a plurality of transmission paths,
Detecting a communication band assigned to a transmission path among the plurality of transmission paths from a central control station that assigns and releases a communication band; and
A communication band control step for controlling the detected communication band so as to be used as a communication band of another transmission path to which no communication band is given,
The plurality of transmission paths include a first transmission path for directly transmitting data from the first wireless communication apparatus to the second wireless communication apparatus, and a first transmission path from the first wireless communication apparatus to the second wireless communication apparatus. A second transmission path for transmitting data via the relay station,
A wireless communication control step of switching a transmission path used for transmitting data to the second wireless communication apparatus between the first transmission path and the second transmission path;
When the wireless communication control step switches the transmission path from the first transmission path to the second transmission path, in the switching process, at least the communication band on the first transmission path, and the second transmission path A wireless communication method in which a state in which a communication band on a third transmission path from a relay station to the second wireless communication device is given is passed. A wireless communication method for transmitting and receiving data between a first wireless communication device and a second wireless communication device via a plurality of transmission paths,
Detecting a communication band assigned to a transmission path among the plurality of transmission paths from a central control station that assigns and releases a communication band; and
A communication band control step for controlling the detected communication band so as to be used as a communication band of another transmission path to which no communication band is given,
The plurality of transmission paths include a first transmission path for directly transmitting data from the first wireless communication apparatus to the second wireless communication apparatus, and a first transmission path from the first wireless communication apparatus to the second wireless communication apparatus. A second transmission path for transmitting data via the relay station,
A wireless communication control step of switching a transmission path used for transmitting data to the second wireless communication apparatus between the first transmission path and the second transmission path;
When the wireless communication control step switches the transmission line from the second transmission line to the first transmission line, at least from the first wireless communication device of the second transmission line to the relay station in the switching process A wireless communication method in which only a communication band on the fourth transmission path is granted. A wireless communication method for transmitting and receiving data between a first wireless communication device and a second wireless communication device via a plurality of transmission paths,
Detecting a communication band assigned to a transmission path among the plurality of transmission paths from a central control station that assigns and releases a communication band; and
A communication band control step for controlling the detected communication band so as to be used as a communication band of another transmission path to which no communication band is given,
The plurality of transmission paths include a first transmission path for directly transmitting data from the first wireless communication apparatus to the second wireless communication apparatus, and a first transmission path from the first wireless communication apparatus to the second wireless communication apparatus. A second transmission path for transmitting data via the relay station,
A wireless communication control step of switching a transmission path used for transmitting data to the second wireless communication apparatus between the first transmission path and the second transmission path;
When the transmission path used for transmitting data from the first wireless communication apparatus to the second wireless communication apparatus is switched between the first transmission path and the second transmission path, the transmission path before switching A method of wireless communication, further comprising: transmitting to the central control station data indicating that data is being transmitted from the first wireless communication device to the second wireless communication device using. A wireless communication method for transmitting and receiving data between a first wireless communication device and a second wireless communication device via a plurality of transmission paths,
Detecting a communication band assigned to a transmission path among the plurality of transmission paths from a central control station that assigns and releases a communication band; and
A communication band control step for controlling the detected communication band so as to be used as a communication band of another transmission path to which no communication band is given;
The central control station is requested to provide a communication band for transmitting data to the second wireless communication apparatus, and the first wireless communication is currently performed depending on whether or not the communication band is provided from the central control station. A free bandwidth confirmation step for confirming whether or not the wireless communication system to which the device belongs has a free communication bandwidth ,
Wireless communication further comprising the step of canceling switching of a transmission path between the first wireless communication device and the second wireless communication device when the free bandwidth confirmation step confirms that the free bandwidth is insufficient. Method. A wireless communication system comprising a first wireless communication device and a second wireless communication device connected to the first wireless communication device via a network, wherein the first wireless communication device comprises:
A transmission / reception unit (206) for transmitting and receiving data to and from the second wireless communication device via a plurality of transmission paths;
A communication band that controls the communication band so that the communication band assigned to a certain transmission line from the central control station that assigns and releases the communication band is used as the communication band of another transmission line that is not assigned a communication band. A control unit (208),
The transmission path includes a first transmission path that directly transmits data to the second wireless communication apparatus, and a second transmission path that transmits data to the second wireless communication apparatus via a relay station,
A wireless communication control unit (205) for switching a transmission line used for transmitting data to the second wireless communication apparatus between the first transmission line and the second transmission line;
When the wireless communication control unit switches the transmission path from the first transmission path to the second transmission path, in the switching process, the communication band on the first transmission path, and the second transmission path A state in which all communication bands of the first transmission path and the second transmission path are given after a state where a communication band on the third transmission path from the relay station to the second wireless communication device is given. Wireless communication system. A wireless communication system comprising a first wireless communication device and a second wireless communication device connected to the first wireless communication device via a network,
The first wireless communication device is:
A transmission / reception unit (206) for transmitting and receiving data to and from the second wireless communication device via a plurality of transmission paths;
A communication band that controls the communication band so that the communication band assigned to a certain transmission line from the central control station that assigns and releases the communication band is used as the communication band of another transmission line that is not assigned a communication band. A control unit (208),
The transmission path includes a first transmission path that directly transmits data to the second wireless communication apparatus, and a second transmission path that transmits data to the second wireless communication apparatus via a relay station,
A wireless communication control unit (205) for switching a transmission line used for transmitting data to the second wireless communication apparatus between the first transmission line and the second transmission line;
When the wireless communication control unit switches the transmission line from the second transmission line to the first transmission line, in the switching process, from the first wireless communication device of the second transmission line to the relay station A wireless communication system in which, after passing through a state where only the communication band on the fourth transmission path is assigned, the state where the communication band of the first transmission path and the fourth transmission path is assigned passes. A wireless communication system including a wireless communication device as a relay station that receives data from a transmission-side wireless communication device via a transmission line and transmits the received data to the reception-side wireless communication device via a transmission line. There,
The transmission path includes a first transmission path that directly transmits data from the transmitting-side wireless communication apparatus to the receiving-side wireless communication apparatus, and the transmitting-side wireless communication apparatus via the relay station to the receiving-side wireless communication apparatus. A second transmission path for transmitting data to the wireless communication device,
The wireless communication device as the relay station is
Requests the central control station, which assigns and releases the communication band, to assign the communication band to the third transmission line from the relay station to the wireless communication device on the receiving side of the second transmission line. When instructed by another wireless communication device as described above, the other band grant request control unit (310) that requests the central control station to grant the communication band of the third transmission path,
A wireless communication system comprising: an added data transmission control unit (305) that controls transmission of data indicating that a communication band has been assigned to the third transmission path. A program for causing a computer to function as a wireless communication device, wherein the program is on the computer,
Transmitting / receiving data to / from other wireless communication devices via a plurality of transmission paths;
A step of controlling the communication band so as to use the communication band assigned to a certain transmission path from the central control station that assigns and releases the communication band as the communication band of another transmission path not provided with the communication band; The transmission path includes a first transmission path that directly transmits data to the other wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station. ,
The program is on the computer,
Executing a step of switching a transmission line used for transmitting data to the other wireless communication device between the first transmission line and the second transmission line;
When switching the transmission line from the first transmission line to the second transmission line, in the switching process, the communication band on the first transmission line, and the other of the second transmission lines from the relay station after a state in which the communication band of the third transmission path to the wireless communication device is granted, the communication band of the first transmission path and the second transmission line has passed the state of being all granted, program. A program for causing a computer to function as a wireless communication device,
The program is on the computer,
Transmitting / receiving data to / from other wireless communication devices via a plurality of transmission paths;
A step of controlling the communication band so as to use the communication band assigned to a certain transmission path from the central control station that assigns and releases the communication band as the communication band of another transmission path not provided with the communication band; The transmission path includes a first transmission path that directly transmits data to the other wireless communication apparatus, and a second transmission path that transmits data to the other wireless communication apparatus via a relay station. ,
The program is on the computer,
Executing a step of switching a transmission line used for transmitting data to the other wireless communication device between the first transmission line and the second transmission line;
When the transmission path is switched from the second transmission path to the first transmission path, only the communication band on the fourth transmission path from the own apparatus to the relay station in the second transmission path is given in the switching process. after a state of being, the first transmission line, and passes the state in which the communication band of the fourth transmission path is applied, the program. A program for causing a computer to function as a wireless communication device, the wireless communication device receives data from the radio communication apparatus on the transmission side through a transmission path, receiving via a transmission path of data that the received A wireless communication device as a relay station that transmits to the wireless communication device on the side,
The transmission path includes a first transmission path that directly transmits data from the transmitting-side wireless communication apparatus to the receiving-side wireless communication apparatus, and the transmitting-side wireless communication apparatus via the relay station to the receiving-side wireless communication apparatus. A second transmission path for transmitting data to the wireless communication device,
The program is on the computer,
Requests the central control station, which assigns and releases the communication band, to assign the communication band to the third transmission line from the relay station to the wireless communication device on the receiving side of the second transmission line. Requesting the central control station to give a communication band of the third transmission path when instructed by another wireless communication device,
And a step of controlling the transmission of data indicating that the communication bandwidth to the third transmission path is assigned, program. Storing program according to any one of claims 20 to 22, the storage medium.

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