JP5301893B2 - Wireless communication system, base station, communication terminal, and wireless communication method - Google Patents

Description

  The present invention relates to a radio communication system, a communication terminal, a base station, and a radio communication method capable of radio communication using a TDMA-TDD system.

  In recent years, communication terminals represented by PHS (Personal Handy phone System) and mobile phones have become widespread, making it possible to make calls and obtain information regardless of location or time. Especially in recent years, the amount of available information has been increasing, and high-speed and high-quality wireless communication systems have been introduced to download large amounts of data.

  In such wireless communication, it is necessary to duplicate signals in order to transmit and receive. Typical duplexing methods include TDD (Time Division Duplex) that switches between transmission and reception by time division and FDD (Frequency Division Duplex) that duplexes transmission and reception by changing the frequency. In addition, as a method for multiple access to communicate with a plurality of communication terminals at the same time, TDMA (Time Division Multiple Access) for switching a plurality of communication terminals by time division, FDMA (Frequency) for dividing a frequency band Typical examples include Division Multiple Access (frequency division multiple access) and CDMA (Code Division Multiple Access) that multiplies a different code for each communication terminal.

  For example, ARIB (Association of Radio Industries and Businesses) STD-28 (Non-Patent Document 1) is used as a PHS communication standard that has been conventionally used. Here, the TDMA-TDD system is adopted. In this communication standard, the base station transmits a control signal, and the mobile station (communication terminal) receives this signal to know the presence of the base station, perform location registration, and start communication. Is configured to do.

  Further, there is an adaptive array antenna technique that uses a plurality of antennas to control the directivity pattern as one means for improving communication quality while maintaining the communication speed.

  Such an adaptive array antenna technique is a technique for generating a composite wave by controlling the phases of radio waves transmitted from a plurality of antennas and controlling the traveling direction of the composite wave. Thus, radio waves can be transmitted in a predetermined direction, so that radio wave interference generated between base stations can be reduced and the transmission distance of radio waves can be extended.

Specifically, by forming beamforming using adaptive array technology, radio waves can be focused in a predetermined direction, and by forming null steering, interference with other base stations can be minimized. It becomes possible. That is, if a communication terminal as a communication partner can be specified at a certain moment, it is possible to form beam forming in the direction of the specified communication terminal and to form null steering in a direction other than the direction of the specified communication terminal. Become.
ARIB RCR STD-28 (Association of Radio Industries and Broadcast Research and Development Center for Radio Systems)

  The control signal transmitted by the base station in the communication standard of Non-Patent Document 1 includes a broadcast signal, a paging signal, and a link channel assignment signal, which are intermittently transmitted in a predetermined pattern every 100 msec.

  The broadcast signal and the paging signal are signals that are widely transmitted to communication terminals within the communication range of the base station, so it is not necessary to use adaptive array technology, but control for establishing communication with a predetermined communication terminal The link channel assignment signal, which is a signal, can use the adaptive array technology and can obtain the effect of the adaptive array technology.

  However, in the communication standard of Non-Patent Document 1 described above, the link channel assignment signal can be transmitted at the timing of transmitting the paging signal when there is no incoming call. Therefore, even if the link channel assignment signal is transmitted using the adaptive array technology at the timing of transmitting the call signal when there is no incoming call, even if the signal is received from the communication terminal in advance and the weight is calculated. When there is an incoming call after that, the call signal is prioritized and transmitted at the timing of transmitting the call signal, so that the weight calculation is wasted.

  In view of such a problem, the present invention provides a wireless communication system, a base, and a base station that can reliably obtain the effect of adaptive array technology by causing a communication terminal to transmit a control signal immediately before the base station transmits the control signal. An object is to provide a station, a communication terminal, and a wireless communication method.

  In order to solve the above problems, a typical configuration of the present invention is a wireless communication system including a communication terminal and a base station that communicates with the communication terminal, and the base station includes a plurality of antennas, A base station transmitting unit that transmits a control signal including at least a paging signal and a link channel assignment signal at a predetermined pattern timing, and a base station receiving unit that receives a link channel establishment request signal from a communication terminal. The terminal includes a terminal receiver that receives a control signal from the base station, a terminal transmitter that transmits a link channel establishment request signal between the link channel assignment signal transmitted from the base station and the control signal immediately before the link channel assignment signal, The base station transmitter performs weight calculation based on the received link channel establishment request signal, and transmits a link channel assignment signal to be transmitted next through a plurality of antennas. And transmitting by the adaptive array technique using a weight that the calculated Te.

  Since the terminal transmitter of the communication terminal transmits the link channel establishment request signal between the control signal transmitted from the base station and the link channel assignment signal (100 msec in ARIB RCR STD-28), the base station After receiving the establishment request signal and performing the weight calculation, the link channel assignment signal is always transmitted. Therefore, the link channel assignment signal can be transmitted using the adaptive array technique without wasting weight calculation. Further, the base station can perform the weight calculation using the link channel establishment request signal for 100 msec before transmitting the link channel assignment signal. Therefore, the base station can perform the weight calculation in a time that is not affected by changes in the radio wave propagation environment, and can use the calculated weight to transmit a link channel assignment signal using adaptive array technology. It becomes.

  The communication terminal in the wireless communication system performs open search when establishing communication, selects a base station having the maximum communication quality value as a base station for communication, and communication quality of the selected base station A communication quality determination unit that determines whether or not the value is equal to or less than a predetermined value, and the terminal transmission unit is transmitted from the base station when the communication quality determination unit determines that the value is equal to or less than the predetermined value. A link channel establishment request signal may be transmitted between the link channel assignment signal to be transmitted and the control signal immediately before.

  As a result of the open search performed by the communication terminal, if the communication quality value of the selected base station is at most a predetermined value or less, if the effect of the adaptive array can be used, communication efficiency is improved and stable communication is performed. It becomes possible.

  The base station in the wireless communication system further includes a packet determination unit that determines whether or not a slot that transmits a control signal in each frame and that does not transmit the control signal is used in a packet. The transmission unit transmits the determination result of the packet determination unit included in the control signal, and when the terminal reception unit of the communication terminal receives the control signal including the determination result that the packet is not used from the base station, The terminal transmitter may transmit the link channel establishment request signal in a slot between the link channel assignment signal transmitted from the base station and the control signal immediately before the link channel assignment signal.

  Since the base station intermittently transmits a control signal at a predetermined interval, a slot that transmits a control signal in each frame and does not transmit the control signal may be used for packet transmission / reception. Therefore, the packet determination unit determines whether or not the slot for transmitting the control signal in each frame is used in the packet. If the packet is not used in the packet, the link channel establishment request signal is transmitted in the slot. It can be transmitted to a communication terminal. Therefore, since the base station receives the link channel establishment request signal after transmitting the control signal before the link channel assignment signal to be transmitted next, it is possible to use the effect of the adaptive array with high accuracy. .

  The control signal including the determination result of the packet determination unit may be a paging signal when there is no incoming call request from another base station.

  By including the determination result of the packet determination unit in the paging signal when there is no incoming call request from another base station, the existing paging signal is used without providing a dedicated signal separately, so that the resources are effectively used. be able to.

  The terminal transmission unit may transmit a link channel establishment request signal a plurality of times between the link channel assignment signal transmitted from the base station and the control signal immediately before the link channel assignment signal.

  When transmitting using the adaptive array technology, weight calculation is performed from the received link channel establishment request signal. At this time, in order for the base station to receive the signal with the same gain as when the signal from the communication terminal is received, when the signal used to perform the weight calculation is received, The radio wave propagation environment for the communication terminal needs to be the same level when transmitting using the result. In other words, in order to obtain the effect of the adaptive array technology, the signal must be transmitted in a short time so that there is almost no change in the radio wave propagation environment after receiving a signal from the communication terminal.

  However, after receiving the link channel establishment request signal, the base station needs to perform various processes for assigning a channel to the communication terminal (for example, searching for a released channel). It will take some time for

  Therefore, the terminal transmission unit transmits the link channel establishment request signal a plurality of times between the link channel assignment signal transmitted from the base station and the control signal immediately before the link channel assignment signal, and the link channel establishment request received first time. Processing for assigning a channel to a communication terminal using a signal can be performed, and weight calculation can be performed based on a link channel establishment request signal from the subsequent communication terminal. Thereby, before transmitting the link channel assignment signal, the link channel establishment request signal for performing the weight calculation can be received in a time shorter than the time required for the process for performing the channel assignment. It is possible to make full use of the effects of adaptive array technology.

  In order to solve the above-described problem, another typical configuration of the present invention is a base station that communicates with a communication terminal, and a plurality of antennas and a control signal including at least a paging signal and a link channel assignment signal are predetermined. A base station transmitter that transmits at the timing of the pattern, a base station receiver that receives a link channel establishment request signal from a communication terminal, a slot that transmits a control signal in each frame, and a slot in which the control signal is not transmitted A packet determination unit that determines whether or not the packet is used in a packet, and the base station transmission unit includes the determination result of the packet determination unit in the control signal and transmits the result to the received link channel establishment request signal Based on the weight, and the link channel assignment signal to be transmitted next is added using the calculated weights via a plurality of antennas. And transmitting by Tibuarei techniques.

  In order to solve the above-described problem, another typical configuration of the present invention is a communication terminal that communicates with a base station, a terminal receiver that receives a control signal from the base station, and a base station that transmits the control signal. A terminal transmission unit that transmits a link channel establishment request signal between the link channel assignment signal and the control signal immediately before the link channel assignment signal.

  In order to solve the above-described problem, another exemplary configuration of the present invention is a wireless communication method using a communication terminal and a base station that includes a plurality of antennas and communicates with the communication terminal. The station transmits a control signal including at least a paging signal and a link channel assignment signal at a timing of a predetermined pattern, and the communication terminal requests a link channel establishment request between the transmitted link channel assignment signal and the control signal immediately before it. The base station calculates the weight based on the received link channel establishment request signal, and uses the calculated weight for the link channel assignment signal to be transmitted next through the plurality of antennas, and the adaptive array technology It is characterized by transmitting by.

  The components corresponding to the technical idea in the wireless communication system and the description thereof can be applied to the base station, the communication terminal, and the wireless communication method.

  As described above, in the wireless communication system of the present invention, the effect of the adaptive array can be reliably obtained by causing the communication terminal to transmit the control signal immediately before the base station transmits the control signal.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  Communication terminals such as PHS terminals and mobile phones construct a wireless communication system that performs wireless communication with base stations that are fixedly arranged at predetermined intervals. Here, the entire wireless communication system will be described first, and then the specific configuration of the base station will be described. In this embodiment, a PHS terminal is cited as a communication terminal. However, the present invention is not limited to such a case. A mobile phone, a notebook personal computer, a PDA (Personal Digital Assistant), a digital camera, a music player, a car navigation system, a portable TV. Various electronic devices capable of wireless communication such as game devices, DVD players, and remote controllers can also be used as communication terminals.

(Wireless communication system 100)
FIG. 1 is an explanatory diagram showing a schematic connection relationship of the wireless communication system 100. The wireless communication system 100 includes base stations 110A and 110B, PHS terminals 120A and 120B, a communication network 130 including an ISDN (Integrated Services Digital Network) line, the Internet, a dedicated line, and the like, and a relay server 140. Consists of.

  In the wireless communication system 100, when a user connects a communication line from his / her PHS terminal 120A to another PHS terminal 120B, the PHS terminal 120A performs an open search and has the best communication quality within the communicable range. A wireless connection request is made to the base station 110A. The base station 110A that has received the wireless connection request requests the relay server 140 to establish a communication connection with the communication partner via the communication network 130, and the relay server 140 refers to the location registration information of the PHS terminal 120B to determine another PHS terminal. For example, the base station 110B within the wireless communication range of 120B is selected to secure a communication path between the base station 110A and the base station 110B, and communication between the PHS terminal 120A and the PHS terminal 120B is established.

  In such a wireless communication system 100, various techniques are employed to improve the communication speed and communication quality between the base station 110A and the PHS terminal 120A or between the base station 110B and the PHS terminal 120B. In the present embodiment, for example, ARIB STD-28 is adopted, and wireless communication based on the TDMA-TDD scheme is executed between the base station and the PHS terminal.

  Hereinafter, specific configurations and operations of the base stations 110A and 110B and the PHS terminals 120A and 120B in the wireless communication system 100 will be described. In the following embodiments, since the base stations 110A and 110B have the same configuration, the configuration of the base station 110A will be described as a representative, and the PHS terminals 120A and 120B have the same configuration, and thus the PHS terminal 120A as a representative. The structure of will be described.

(Base station 110A)
FIG. 2 is a functional block diagram showing the hardware configuration of the base station 110A. The base station 110A includes a base station control unit 210, a base station memory 212, a base station wireless communication unit 214, a base station wired communication unit 216, and a plurality of antennas 218.

  The base station control unit 210 manages and controls the entire base station 110 by a semiconductor integrated circuit including a central processing unit (CPU). In addition, the base station control unit 210 controls communication connection of the PHS terminal 120 to the communication network 130 and other PHS terminals 120 using the program in the base station memory 212. The base station memory 212 includes ROM, RAM, EEPROM, nonvolatile RAM, flash memory, HDD, and the like, and stores programs processed by the base station control unit 210, time information, and the like.

  The base station wireless communication unit 214 establishes communication with the PHS terminal 120 via the antenna 218 and transmits / receives data. The base station wired communication unit 316 can be connected to various servers including the relay server 140 via the communication network 130.

  In this embodiment, the base station control unit 210 also functions as a base station transmission unit 220, a base station reception unit 222, a packet determination unit 224, and a weight calculation unit 226.

  The base station transmission unit 220 includes a broadcast signal (BCCH: BroadCast Control Channel, hereinafter simply referred to as BCCH), a paging signal (PCH: Paging Channel, hereinafter simply referred to as PCH), and a link channel assignment signal (downlink SCCH: Signaling). A control signal (CCH: hereinafter referred to simply as CCH) including a control channel (hereinafter simply referred to as downlink SCCH) is transmitted at a predetermined pattern timing.

  BCCH is a signal including information for location registration, information on channel structure, system information, and the like, and is transmitted from base station 110A to PHS terminal 120A by broadcast. The PCH is a signal for notifying an incoming call to the PHS terminal 120A in the general call area when there is an incoming call request. The downlink SCCH is a signal including information necessary for call connection.

  FIG. 3 is an explanatory diagram for explaining a configuration of a transmission pattern of a control signal transmitted from the base station according to the present embodiment. As shown in FIG. 3A, in ARIB STD-28, the base station transmission unit 220 of the base station 110A intermittently transmits the CCH with a predetermined time (100 msec) in a predetermined order. In FIG. 3, BCCH is indicated by hatching, PCH is indicated by black, and downlink SCCH is indicated by cross hatching.

  As shown in FIG. 3B, in the TDMA-TDD system which is the communication system of the present embodiment, a frame (time) in which a signal is transmitted from the base station 110A to the PHS terminal 120A, and the base station 110A from the PHS terminal 120A. The frame (time) in which a signal is transmitted is different. Here, a frame in which a signal is transmitted from the base station 110A to the PHS terminal 120A is referred to as downlink (downlink), and a frame in which a signal is transmitted from the PHS terminal 120A to the base station 110A is referred to as uplink (uplink).

  In ARIB STD-28, a frame includes a downlink and a time slot (TDMA slot) obtained by dividing the uplink into four in the time axis direction, and the time length of one time slot is 625 μsec.

As shown in FIG. 3 (a), in this embodiment, the base station transmission unit 220 uses the first slot to change the CCH every 100 msec (that is, 20 frames) BCCH, PCH, PCH, downlink SCCH, PCH, PCH. , Downlink SCCH, PCH, PCH, downlink SCCH, PCH, and PCH. That is, in the present embodiment, the first slot of the time slot (TDMA slot) obtained by dividing the downlink and the uplink into four in the time axis direction is a control signal slot assigned to control signal transmission. In the ARIB STD-28, it is possible to transmit PCH when there is an incoming call request in a slot for transmitting PCH, and idle PCH or downlink SCCH when there is no incoming call request.

  Further, base station transmission section 220 receives a plurality of link channel establishment request signals (uplink SCCH: Signaling Control Channel, hereinafter simply referred to as uplink SCCH) transmitted from PHS terminal 120 by base station reception section 222 described later. A process for allocating a channel to the PHS terminal 120A using the uplink SCCH received at the first time is performed, a weight calculation is performed based on the uplink SCCH from the second and subsequent PHS terminals 120A, and the downlink SCCH to be transmitted next Through the plurality of antennas 218, transmission is performed by the adaptive array technique using the calculated weight.

  In this embodiment, the antenna 218 has an adaptive array function, and the directivity of radio waves to be transmitted and received can be dynamically changed by forming beam forming and null steering. Here, in the beam forming, the radio wave intensity is strengthened by matching the phases of the radio waves output from the plurality of antennas 218, and the position of the null steering is offset by shifting the phase of the radio wave, and the radio wave intensity is weakened. .

  The base station receiving unit 222 receives the uplink SCCH transmitted from the PHS terminal 120A via the base station wireless communication unit 214. The uplink SCCH from the PHS terminal 120A received by the base station reception unit 222 is transmitted to the weight calculation unit 226 described later.

  The packet determination unit 224 determines whether or not a slot that transmits a CCH in each frame (the first slot in the present embodiment) and that does not transmit the control signal is used in the packet.

  In this embodiment, the determination result of the packet determination unit 240 is transmitted to the PHS terminal 120A by being included in the idle PCH that is the PCH when there is no incoming call in the slot for transmitting the PCH.

  FIG. 4 is an explanatory diagram showing the message format of the PCH and idle PCH when there is an incoming call request. FIG. 4A shows the arrangement of each information in the PCH when there is an incoming call request. b) shows the arrangement of each information in the PCH, that is, the idle PCH when there is no incoming call request. In FIG. 4, the horizontal axis is delimited by bits 230, and the vertical axis is delimited by octets 232. Octet 232 is 8-bit information.

  As shown in FIG. 4A, when there is an incoming call request from another base station 110B, the PCH is configured to include a paging service type, a PS number, an extended paging service type, and a notification reception instruction.

  As shown in FIG. 4B, when there is no incoming call request, the result of the packet determination unit 240 is written in the packet using flag 234 in the second stage of the octet 232. As a result of the packet determination unit 240, when the slot for transmitting the CCH in each frame (the first slot in this embodiment) is used in the packet, (1) is set in the packet using flag 234. On the other hand, when the slot for transmitting the CCH in each frame (the first slot in this embodiment) is not used in a packet, (0) is set in the packet using flag 234.

  As described above, by using the idle PCH, the result of the packet determination unit 224 can be transmitted to the PHS terminal 120A without providing a dedicated signal. Therefore, effective utilization of CCH resources can be achieved.

  The weight calculation unit 226 performs weight calculation using a plurality of uplink SCCHs received by the base station reception unit 222.

(PHS terminal 120A)
FIG. 5 is a functional block diagram illustrating a hardware configuration of the PHS terminal 120A, and FIG. 6 is a perspective view illustrating an appearance of the PHS terminal 120A. The PHS terminal 120A includes a terminal control unit 310, a terminal memory 312, a display unit 314, an operation unit 316, a voice input unit 318, a voice output unit 320, and a terminal wireless communication unit 322. .

  The terminal control unit 310 manages and controls the entire PHS terminal 120A using a semiconductor integrated circuit including a central processing unit (CPU). In addition, the terminal control unit 310 performs a call function, a mail transmission / reception function, an imaging function, a music playback function, and a TV viewing function using the program in the terminal memory 312.

  The terminal memory 312 is composed of ROM, RAM, EEPROM, nonvolatile RAM, flash memory, HDD (Hard Disk Drive), and the like, and stores programs processed by the terminal control unit 310, audio data, and the like.

  The display unit 314 includes a liquid crystal display, EL (Electro Luminescence), etc., and is stored in the terminal memory 312 or provided from an application server (not shown) via the communication network 130. A GUI (Graphical User Interface) can be displayed. The operation unit 316 includes switches such as a keyboard, a cross key, and a joystick, and accepts user operation inputs.

  The voice input unit 318 includes voice recognition means such as a microphone, and converts a user voice input during a call into an electrical signal that can be processed in the PHS terminal 120A. The voice output unit 320 includes a speaker, and converts the voice signal of the other party received by the PHS terminal 120A into voice and outputs the voice. In addition, a ring tone, an operation sound of the operation unit 316, an alarm sound, and the like can be output.

  The terminal wireless communication unit 322 performs wireless communication with the base station 110 </ b> A in the communication network 130. As the wireless communication of this embodiment, a time division multiple access (TDMA) in which a plurality of time slots obtained by time-dividing frames in the base station 110A are assigned to the channels of the PHS terminal 120 for communication is adopted. Has been.

  In the present embodiment, the terminal control unit 310 also functions as a base station selection unit 330, a communication quality determination unit 332, a terminal transmission unit 334, and a terminal reception unit 336.

  When the PHS terminal 120A establishes communication, the base station selection unit 330 performs an open search, measures the communication quality value of the base station 110A within the communicable range, and selects the base station 110A having the maximum communication quality value. The base station 110A that performs communication is selected.

  In the present embodiment, the base station selection unit 330 measures a received signal strength indicator (RSSI) as a communication quality value, but is not limited to this, and a signal-to-interference noise ratio (SINR: Signal) To Interference and Noise Ratio), bit error rate (BER), frame error rate (FER), and the like may be measured.

  The communication quality determination unit 332 determines whether the RSSI of the base station 110A selected by the base station selection unit 330 is equal to or less than a predetermined value.

  The terminal transmission unit 334 transmits the uplink SCCH a plurality of times between the downlink SCCH transmitted from the base station 110A and the immediately preceding CCH (100 msec in this embodiment) via the terminal wireless communication unit 322.

  FIG. 7 is an explanatory diagram for explaining the timing at which the terminal transmission unit according to the present embodiment transmits the uplink SCCH. As shown in FIG. 7A, the terminal transmission unit 334 transmits the downlink SCCH (indicated by cross-hatching in FIG. 7A) transmitted from the base station 110A and the PCH just before it (black in FIG. 7A). The uplink SCCH (indicated by an arrow in FIG. 7 (a)) is transmitted a plurality of times in the interval (indicated by 100msec in this embodiment).

  In this embodiment, when the communication quality determination unit 332 determines that the RSSI of the base station 110A is equal to or less than a predetermined value, the terminal transmission unit 336 transmits the uplink SCCH multiple times via the terminal wireless communication unit 322.

  As a result of the open search performed by the base station selection unit 330, if the communication quality value (RSSI) of the selected base station 110A is less than or equal to a predetermined value, if the effect of the adaptive array can be used, the communication efficiency is improved and stable. Communication can be performed. Therefore, if the communication quality determining unit 332 determines that the terminal transmission unit 334 transmits the uplink SCCH a plurality of times, the base station 110A transmits the uplink SCCH to the PHS terminal 120A on the first received SCCH. Processing for performing channel assignment is performed, and weight calculation can be performed based on the uplink SCCH from the second and subsequent PHS terminals 120A. As a result, before transmitting the downlink SCCH, the base station 110A can receive the uplink SCCH for performing weight calculation in a time shorter than the time required for the channel assignment process. The downlink SCCH to be transmitted to can be transmitted by using an adaptive array technology. Thereby, the effect of the adaptive array can be used effectively.

In this embodiment, the terminal transmission unit 334 receives the CCH and the downlink SCCH transmitted from the base station 110A when the terminal reception unit 336, which will be described later, receives a determination result indicating that the packet is not used in the packet from the base station 110A. The uplink SCCH is transmitted a plurality of times in a slot (control signal slot, that is, the first slot) in which a control signal is transmitted in each frame.

  Since the base station 110A transmits the CCH only once every 100 msec (20 frames), one slot is opened for each 19 frames. Therefore, there are cases where 19 open slots (hereinafter simply referred to as open slots) are used in packets for effective use.

  However, when a determination result indicating that the packet is not used in the packet is received from the base station 110A, the uplink SCCH can be transmitted in the open slot. Accordingly, since the uplink SCCH (indicated by the dot pattern in FIG. 7B) can be transmitted up to 19 times in a short period (100 msec) (see FIG. 7B), the base station 110A performs 18 times (the first time). The uplink SCCH can be used to improve the accuracy of the adaptive array based on the uplink SCCH used for channel allocation to the PHS terminal 120A. Further, if the uplink SCCH used for weight calculation is transmitted once more in 5 msec immediately before the base station 110A transmits the downlink SCCH, the adaptive array technology can be used while minimizing the influence of changes in the radio wave propagation environment. Can do.

  The terminal receiving unit 336 receives CCH including BCCH, PCH, idle PCH, and downlink SCCH transmitted from the base station 110A via the terminal wireless communication unit 322.

  In the wireless communication system 100 described above, since the terminal transmission unit 334 of the PHS terminal 120A transmits the uplink SCCH multiple times between the CCH transmitted from the base station 110A and the downlink SCCH (100 msec), the base station 110A Weight calculation can be performed using the uplink SCCH received in 100 msec before transmitting the SCCH. Therefore, the base station 110A can perform the weight calculation in a time that is not affected by the change in the radio wave propagation environment, and can accurately transmit the downlink SCCH using the adaptive array technology. Next, a wireless communication method for performing wireless communication using the above-described base station 110A and PHS terminal 120A will be described.

(Wireless communication method)
FIG. 8 is a flowchart showing the flow of processing of the wireless communication method according to the present embodiment.

  When the PHS terminal 120A attempts to establish communication, an open search is performed to select the base station 110A having the largest RSSI (S400: base station selection step). In the base station selection step S400, it is determined whether or not the RSSI of the selected base station 110A is equal to or less than a predetermined value (S402: communication quality determination step).

  On the other hand, the base station 110A determines whether or not the slot for transmitting CCH in each frame (the first slot in this embodiment) is used in a packet (S404: CCH determination step), and the determination result is set to PCH. It is included in the idle PCH, which is the PCH when there is no incoming call in the slot to be transmitted, and is transmitted to the PHS terminal 120A (S406: determination result transmission step).

  Whether or not the PHS terminal 120A uses a slot for transmitting the CCH transmitted from the base station 110A in the determination result transmission step S406 and in which the CCH is not transmitted (the first slot in the present embodiment) is used in the packet. The determination result is received (S408: determination result reception step).

  When the RSSI is equal to or less than a predetermined value in the communication quality determination step S402 and the determination result received in the determination result reception step S408 is not used in the packet (S410: determination step), the PHS terminal 120A determines from the base station 110A. Before the downlink SCCH is transmitted, the uplink SCCH is continuously transmitted every 5 msec (S412: multiple times transmission step).

  The base station 110A determines whether or not the uplink SCCH has been received multiple times (S414: multiple reception step), and when the uplink SCCH is received multiple times, calculates the weight based on the received uplink SCCH. Then, the downlink SCCH to be transmitted next is transmitted by the adaptive array technique using the weight calculated through the plurality of antennas (S416: AAA transmission step).

  When the RSSI is not less than or equal to the predetermined value in the communication quality determination step S402 (NO in S402), or the determination result received in the determination result reception step S408 is used in the packet, the PHS terminal 120A Before the downlink SCCH is transmitted from the base station 110A, the uplink SCCH is transmitted once (S418: one transmission step). In this case, the base station 110A performs omni-transmission (non-directional transmission) on the next downlink SCCH to determine that the uplink SCCH is not received a plurality of times in multiple reception step S414 (S420: Omni transmission step). ).

  As described above, according to the wireless communication system of the present embodiment, the terminal transmission unit 334 of the PHS terminal 120A transmits the uplink SCCH a plurality of times between the CCH transmitted from the base station 110A and the downlink SCCH (100 msec). Therefore, the base station 110A can perform the weight calculation in 100 msec, which is a time that is not affected by the change in the radio wave propagation environment, and can transmit the downlink SCCH by the adaptive array technology.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  Note that each step in the wireless communication method of the present specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processing in parallel or a subroutine.

  The present invention is applicable to a wireless communication system, a communication terminal, a base station, and a wireless communication method capable of wireless communication using the TDMA-TDD system.

It is explanatory drawing which showed the rough connection relation of the radio | wireless communications system. It is the functional block diagram which showed the hardware constitutions of the base station. It is explanatory drawing for demonstrating the structure of the transmission pattern of the control signal concerning this embodiment. It is explanatory drawing which showed the message format of PCH and idle PCH when there exists an incoming call request | requirement. It is the functional block diagram which showed the hardware constitutions of the PHS terminal. It is the perspective view which showed the external appearance of the PHS terminal. It is explanatory drawing for demonstrating the timing which the terminal transmission part concerning this embodiment transmits uplink SCCH. It is the flowchart which showed the flow of the process of the radio | wireless communication method concerning this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Wireless communication system 110A, 110B ... Base station 120A, 120B ... PHS terminal 130 ... Communication network 140 ... Relay server 210 ... Base station control part 212 ... Base station memory 214 ... Base station wireless communication part 216 ... Base station wired communication part 218 ... Antenna 220 ... Base station transmission unit 222 ... Base station reception unit 224 ... Packet determination unit 226 ... Weight calculation unit 230 ... Bit 232 ... Octet 234 ... Packet using flag 310 ... Terminal control unit 312 ... Terminal memory 314 ... Display unit 316 ... Operation unit 318 ... Audio input unit 320 ... Audio output unit 322 ... Terminal wireless communication unit 330 ... Base station selection unit 332 ... Communication quality determination unit 334 ... Terminal transmission unit 336 ... Terminal reception unit

Claims (6)

The divided slots at a communication terminal and a frame A wireless communication system comprising a base station communicating allocated to the communication terminal,
The communication terminal includes a terminal reception unit that receives a signal from the base station;
A terminal transmitter that transmits a link channel establishment request signal (uplink SCCH) to the base station,
The base station includes a multiple antenna,
A base station receiver for receiving a signal from the communication terminal;
A base station transmitting unit which transmits a control signal including the call out signal (PCH) and link channel allocation signal (downlink SCCH) at the timing of the predetermined pattern,
A packet determination unit for determining whether or not a control signal slot allocated for transmission of the control signal is vacant at a timing at which the control signal is not transmitted ,
The base station transmission unit transmits the control signal immediately before the link channel assignment signal (downlink SCCH) in the predetermined pattern including the determination result of the packet determination unit,
When the terminal transmission unit receives the determination result that the control signal slot is empty, the terminal transmission unit transmits the link channel establishment request signal (uplink SCCH) a plurality of times using the control signal slot,
The base station transmission unit uses the weight calculated based on the link channel establishment request signal (uplink SCCH) transmitted using the control signal slot to adaptively allocate the link channel assignment signal (downlink SCCH). A wireless communication system, characterized by transmitting by technology. The control signal immediately before the link channel assignment signal (downlink SCCH) is a paging signal (PCH),
The base station transmission unit transmits the idle PCH including the determination result when transmitting the idle PCH that is the call signal when there is no incoming call request from another base station. The wireless communication system according to claim 1 . The communication terminal, a base station communication quality value maximum and open a search in establishing communication, a base station selecting section for selecting a base station that performs communication,
The communication quality value of the selected base station further comprises a communication quality judging unit equal to or smaller than the predetermined value,
The terminal transmitting unit transmits the link channel establishment request signal (uplink SCCH) a plurality of times using the free control signal slot when it is determined that the communication quality value is equal to or less than a predetermined value. the wireless communication system according to claim 1 or 2, characterized in. A base station that performs communication by allocating a slot obtained by time-sharing a frame to a communication terminal ,
Multiple antennas,
A base station receiver for receiving a signal from the communication terminal;
A base station transmitting unit which transmits a control signal including the call out signal (PCH) and link channel allocation signal (downlink SCCH) at the timing of the predetermined pattern,
A packet determination unit for determining whether or not a control signal slot allocated for transmission of the control signal is vacant at a timing at which the control signal is not transmitted,
The base station transmitter
The control signal immediately before the link channel assignment signal (downlink SCCH) in the predetermined pattern is transmitted including the determination result of the packet determination unit,
When a link channel establishment request signal (uplink SCCH) is received from the communication terminal a plurality of times , the link channel assignment signal (downlink ) is calculated using the weight calculated based on the link channel establishment request signal (uplink SCCH). (SCCH) is transmitted by adaptive array technology. A communication terminal which performs communication by being assigned a slot obtained by time-dividing a frame from a base station,
A terminal receiving unit for receiving signals from the base station,
Wherein a terminal transmitting section that transmits a link channel establishment request signal (uplink SCCH) to a base station,
The terminal transmitter is
Based on the control signal immediately before the link channel allocation signal (downlink SCCH) transmitted from the base station, a determination result is obtained that the control signal slot allocated for transmission of the control signal is vacant at a timing at which the control signal is not transmitted. A communication terminal characterized in that the link channel establishment request signal (uplink SCCH) is transmitted a plurality of times using the free control signal slot . A base station that performs communication by allocating a time-division slot to a communication terminal transmits a control signal including a paging signal (PCH) and a link channel allocation signal (downlink SCCH) at a predetermined pattern timing,
A wireless communication method in which a communication terminal communicating with the base station transmits a link channel establishment request signal (uplink SCCH) to the base station ,
The base station determines whether a control signal slot allocated for transmission of a control signal is vacant at a timing at which the control signal is not transmitted to the control signal immediately before the link channel allocation signal (downlink SCCH) in the predetermined pattern. Including the determination result indicating
When the communication terminal receives the determination result that the control signal slot is empty, the communication terminal transmits the link channel establishment request signal (uplink SCCH) a plurality of times using the control signal slot,
The base station uses the weight calculated based on the link channel establishment request signal (uplink SCCH) transmitted using the control signal slot, to transmit the link channel assignment signal (downlink SCCH) using adaptive array technology. A wireless communication method characterized by transmitting.

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