JP4639845B2 - Wireless communication apparatus, wireless communication system, wireless communication method, and program - Google Patents

Description

  The present invention relates to a wireless communication device, a wireless communication system, a wireless communication method, and a wireless communication program that communicate with each other between a plurality of wireless communication devices such as a wireless LAN (Local Area Network). The present invention relates to a wireless communication device, a wireless communication system, a wireless communication method, and a program when a wireless communication network is constructed by performing direct communication.

  In recent years, an ad-hoc type wireless communication network has been devised in which a wireless communication network is constructed by asynchronously performing direct communication between wireless communication devices. An ad hoc type wireless communication network is particularly suitable for a small-scale wireless network composed of a relatively small number of clients because any terminal (wireless communication device) can communicate with each other without providing a specific control station.

  In recent years, a method called “ultra-wide band (UWB) communication” for performing wireless communication by placing information on a very weak broadband signal has attracted attention as a wireless communication system for realizing short-range ultrahigh-speed transmission.

  The UWB transmission scheme includes an MB-UWB scheme that uses a multiband OFDM signal that uses a number of subcarrier signals by frequency hopping, and a DS (Direct Sequence) information signal spreading rate that is as high as possible. -There are two types of UWB systems. Both systems realize high-speed data transmission by performing transmission / reception by spreading over an ultra-wideband frequency range of 3 GHz to 10 GHz, for example. This is a method of transmitting and receiving a pulsed pulse signal sequence wirelessly. For example, in the standardization work of IEEE 802.15.3, for example, a method of performing communication by forming a piconet between wireless communication devices that perform ultra-wideband wireless communication is being standardized.

  In such a wireless communication network, a predetermined frame period is used, and wireless communication is performed by allocating a certain period within the frame period as a transmission period for transmitting own information to each wireless communication apparatus constituting the network. Has been done. In an ad-hoc type wireless communication network, there is no control station that manages the network. Therefore, each wireless communication device transmits and receives a beacon signal to each other to notify other wireless communication devices of the presence of other wireless communication devices. Frame period synchronization is performed between wireless communication devices constituting a network by grasping the existence of a communication device.

For example, as a method of synchronizing the frame period, a wireless communication apparatus newly joining the network monitors the transmission period immediately before the transmission period (slot) that the wireless communication apparatus intends to use, and the transmission period in the next frame period Based on the difference between the start position and the start position of the transmission period expected in the own frame period, the own transmission timing is determined by synchronizing the frame period with other wireless communication devices. (For example, refer to “Patent Document 1”.) In this prior art, by providing a monitor unit, the reception time of data received later than its own reception timing is measured. In addition, by providing a plurality of monitoring units, the delay time of information received in each reception period is also acquired.
Japanese Patent Laid-Open No. 10-51376 (FIG. 3)

However, the conventional technique (Patent Document 1), it is corrected to synchronize so as one of the wireless communication device is another wireless communication device assigned to the transmission period of the immediately preceding transmit period assigned thereto However, it was not possible to synchronize directly with other wireless communication devices. That is, an ad hoc wireless communication network is configured with a plurality of wireless communication devices, and when the frame periods of the wireless communication devices are not synchronized, direct synchronization with other wireless communication devices could not be achieved. .

  In addition, the frame period can be corrected for information received later than the start position of its own reception period, but information received earlier than the start position of its own reception period cannot be recognized. The frame period could not be corrected based on the information received earlier.

  Therefore, in the present invention, when an ad hoc wireless communication network is configured by a plurality of wireless communication devices, a beacon signal can be received even when the wireless communication devices are not synchronized, and the beacon signal is received. Wireless communication apparatus and wireless communication capable of correcting their frame period to be synchronized with the frame period of other wireless communication apparatuses constituting the wireless communication network based on the difference between the position and the start position of its own beacon signal reception period It is an object to provide a system, a wireless communication method, and a wireless communication program.

  The present invention has been made to solve the above problems, and a first aspect of the present invention is a wireless communication device that forms an ad hoc wireless communication network by transmitting and receiving beacon signals to and from other wireless communication devices. A time measuring means for measuring time, a frame period storing means for storing a frame period in which a plurality of beacon signal receiving periods are provided adjacent to predetermined positions, a beacon signal storing means for storing beacon signals, The storage position specifying means for specifying the position where the beacon signal is stored and the storage position specifying means are associated with the next beacon signal receiving period earlier than the time when the start position of the beacon signal receiving period is timed. And a storage position control means for moving to a specified position. Thus, when a beacon signal to be received in the next beacon signal reception period is received earlier than the start position of the beacon signal reception period is timed, the beacon associated with the next beacon reception period This brings about the effect of storing in the signal storage area. In addition, even when two beacon signals are received during one beacon signal reception period, an effect of storing each beacon signal in a beacon signal storage area to be stored is brought about.

  According to a second aspect of the present invention, there is provided a time measuring means for measuring time in a predetermined unit time in a wireless communication device that constitutes an ad hoc wireless communication network by transmitting / receiving a beacon signal to / from another wireless communication device. A frame period storage means for storing a plurality of beacon signal reception periods and a self-beacon transmission period adjacent to a predetermined position for storing a frame period; and a start position of the beacon signal reception period is the unit time. When the time is counted as a fraction, the position obtained by rounding down the fraction and adding 1 to the unit time is changed to the start position of the beacon signal reception period, and the start position of the beacon signal transmission period is counted as the fraction. In the case, the start position changing means for changing the position rounded down to the start position of the beacon signal transmission period, and the beacon A frame period correcting means for correcting the start position of the frame period based on the reception start position of the beacon signal received after the start position of the signal reception period or the changed start position. It is a communication device. Thereby, all the start positions of the beacon signal reception period or the beacon signal transmission period provided in the frame period may be measured in integers in unit time, and the process of managing the start position of each period is simplified. Bring. Further, a difference of “1” is generated in unit time between the start position of the beacon signal reception period and the start position of the beacon signal transmission period, and the timing at which the beacon signal is transmitted is set earlier. Therefore, when correcting the frame period based on the reception start position of the beacon signal received with a delay from the start position of its own beacon signal reception period, the necessity for correction is reduced, and the correction process for the start position of the frame period is performed. The effect of reducing such a load is brought about.

  According to a third aspect of the present invention, in a wireless communication device that forms an ad hoc wireless communication network by transmitting / receiving a beacon signal to / from another wireless communication device, time measuring means for measuring time, and a plurality of beacon signals Frame period storage means for storing a frame period provided adjacent to a predetermined position in the reception period, and information regarding the reception start position of the beacon signal received after the start position of the beacon signal reception period is the beacon signal. Reception position storage means that is stored as information related to the time measured between the start position of the reception period and the reception start position, and the reception start position of the beacon signal received most recently from the start position of the beacon signal reception period Frame period correcting means for correcting the start position of the frame period based on the information regarding Is a wireless communication apparatus according to claim. Thereby, compared with the case where the reception start position (reception start time) of a beacon signal is managed as an absolute time, the amount of information necessary for managing the reception start position of the beacon signal is reduced. In addition, based on the information on the reception start position of the beacon signal, the frame period that is the latest among the other wireless communication apparatuses constituting the wireless communication network is slower than the start position of the frame period counted by the own wireless communication apparatus. This brings about an effect of correcting the start position of its own frame period in accordance with the wireless communication device whose start position is timed.

  In the third aspect of the present invention, the reception position storage means can store only information related to the reception start position of the beacon signal received with the latest delay from the start position of the beacon signal reception period. Thereby, since it is not necessary to store the information regarding the reception start position of each beacon signal for all beacon reception periods, the amount of information necessary for managing the reception start position of the beacon signal is further reduced. .

  According to a fourth aspect of the present invention, there is provided a time measuring means for measuring time in a predetermined unit time in a wireless communication device constituting an ad hoc type wireless communication network by transmitting / receiving a beacon signal to / from another wireless communication device. A plurality of beacon signal reception periods and a self-beacon transmission period adjacent to a predetermined position; a frame period storage means for storing a frame period; a beacon signal storage means for storing a beacon signal; The storage position specifying means for specifying the position where the beacon signal is stored, and the storage position specifying means are associated with the next beacon signal reception period earlier than the time when the start position of the beacon signal reception period is timed. The storage position control means for moving to a different position and the start position of the beacon signal reception period are counted in fractions in the unit time. In the case where the fraction is rounded down and the unit time is added to 1 position is changed to the start position of the beacon signal reception period, and the start position of the beacon signal transmission period is measured by the fraction, the fraction is The start position changing means for changing the truncated position to the start position of the beacon signal transmission period, and the information regarding the reception start position of the beacon signal received after the start position of the beacon signal reception period or the changed start position Reception position storage means that is stored as information related to the time measured from the start position of the beacon signal reception period to the reception start position, and reception of the beacon signal received most recently from the start position of the beacon signal reception period Frame period correction means for correcting the start position of the frame period based on information on the start position. Is a wireless communication apparatus according to claim. Thus, when a beacon signal to be received in the next beacon signal reception period is received earlier than the start position of the beacon signal reception period is timed, the beacon associated with the next beacon reception period This brings about the effect of storing in the signal storage area. In addition, even when two beacon signals are received during one beacon signal reception period, an effect of storing each beacon signal in a beacon signal storage area to be stored is brought about. Further, all the start positions of the beacon signal reception period or the beacon signal transmission period provided in the frame period may be measured in integers in unit time, and the process for managing the start position of each period is simplified. . Furthermore, since the frame period is corrected based on the reception start position of the beacon signal received later than its own beacon signal reception start position, the unit time is set between the start position of the beacon signal reception period and the start position of the beacon signal transmission period. Effect of reducing the need for correction of the frame period and reducing the load related to the correction process of the start position of the frame period by causing a difference of “1” in the frame and increasing the timing at which the beacon signal is transmitted. Bring.

  Further, according to a fifth aspect of the present invention, in a wireless communication device that constitutes an ad hoc wireless communication network by transmitting and receiving beacon signals to and from other wireless communication devices, time measuring means for measuring time, and a plurality of beacon signals A frame period storage means for storing a frame period provided adjacent to a predetermined position in a reception period, a beacon signal storage means for storing a beacon signal, and a storage position for designating a position for storing the beacon signal And a storage position control means for moving the storage position specifying means to a position associated with the next beacon signal reception period when a predetermined time is counted from the start position of the beacon signal reception period. This is a wireless communication device. Thus, when a beacon signal to be received in the next beacon signal reception period is received earlier than the end position of the beacon signal reception period is timed, the beacon associated with the next beacon reception period is received. This brings about the effect of storing in the signal storage area. In addition, even when two beacon signals are received during one beacon signal reception period, an effect of storing each beacon signal in a beacon signal storage area to be stored is brought about.

  According to a sixth aspect of the present invention, there is provided a clocking means for clocking time in a predetermined unit time in a wireless communication device constituting an ad hoc type wireless communication network by transmitting and receiving a beacon signal with another wireless communication device. A frame period storage means for storing a plurality of beacon signal reception periods and a self-beacon transmission period adjacent to a predetermined position for storing a frame period; and a start position of the beacon signal reception period is the unit time. In this case, the position where the fraction is rounded down is changed to the start position of the beacon signal reception period, and the fraction is rounded down when the start position of the beacon signal transmission period is counted as the fraction. Starting position changing means for changing the position obtained by adding 1 in the unit time to the starting position of the beacon signal transmission period; Frame period correcting means for correcting the start position of the frame period based on the reception start position of the beacon signal received before the start position of the signal reception period or the changed start position. A wireless communication device. Thereby, all the start positions of the beacon signal reception period or the beacon signal transmission period provided in the frame period may be measured in integers in unit time, and the process of managing the start position of each period is simplified. Bring. Further, a difference of “1” is generated in unit time between the start position of the beacon signal reception period and the start position of the beacon signal transmission period, and the timing at which the beacon signal is transmitted is set late. Therefore, when correcting the frame period based on the reception start position of the beacon signal received earlier than the start position of its own beacon signal reception period, the necessity of correction is reduced, and the correction process of the start position of the frame period is performed. The effect of reducing such a load is brought about.

  In addition, according to a seventh aspect of the present invention, in a wireless communication device that forms an ad hoc wireless communication network by transmitting and receiving beacon signals to and from other wireless communication devices, time measuring means for measuring time, and a plurality of beacon signals Frame period storage means for storing a frame period provided adjacent to a predetermined position for a reception period, and information regarding the reception start position of the beacon signal received before the start position of the beacon signal reception period are the beacon. A reception position storage means that is stored as information relating to a time measured between a signal reception start position and a start position of the beacon signal reception period; and a beacon signal received earlier than the start position of the beacon signal reception period. A frame period correction method for correcting the start position of the frame period based on information on the reception start position. It is a wireless communication apparatus characterized by comprising and. Thereby, compared with the case where the reception start position (reception start time) of a beacon signal is managed as an absolute time, the amount of information necessary for managing the reception start position of the beacon signal is reduced. Also, based on the information about the reception start position of the beacon signal, the frame period of the earliest of the frame period start position measured by the own wireless communication apparatus among other wireless communication apparatuses constituting the wireless communication network. This brings about an effect of correcting the start position of its own frame period in accordance with the wireless communication device whose start position is timed.

  In the seventh aspect of the present invention, the reception position storage means can store only information related to the reception start position of the beacon signal received earlier than the start position of the beacon signal reception period. Thereby, since it is not necessary to store the information regarding the reception start position of each beacon signal for all beacon reception periods, the amount of information necessary for managing the reception start position of the beacon signal is further reduced. .

  According to an eighth aspect of the present invention, there is provided a time measuring means for measuring time in a predetermined unit time in a wireless communication device constituting an ad hoc wireless communication network by transmitting / receiving a beacon signal to / from another wireless communication device. A plurality of beacon signal reception periods and a self-beacon transmission period adjacent to a predetermined position, a frame period storage means for storing a frame period, and a plurality of beacon signal reception periods corresponding to each beacon signal reception period Beacon signal storage means having a beacon signal storage area in which beacon signals received during each beacon signal reception period are stored, storage position specifying means for specifying a beacon signal storage area for storing the beacon signal, and the beacon signal When a predetermined time is counted from the start position of the reception period, the storage position specifying means receives the next beacon signal. Storage position control means for designating a beacon signal storage area associated with a period, and when the start position of the beacon signal reception period is counted as a fraction in the unit time, the position where the fraction is truncated is received as the beacon signal. When the start position of the beacon signal transmission period is counted as the fraction, the position is rounded down and the unit time is added to the start position of the beacon signal transmission period. Information on the reception start position of the beacon signal received before the start position of the beacon signal reception period or the start position after the change is changed from the reception start position of the beacon signal to the beacon signal reception period. A reception position storage means for storing information relating to the time measured until the start position; It is a wireless communication apparatus characterized by comprising a frame period correcting means for correcting the start position of the frame period based on the information on the reception start position of the most delayed beacon signal received from the start position of the reception period. Thus, when a beacon signal to be received in the next beacon signal reception period is received earlier than the end position of the beacon signal reception period is timed, the beacon associated with the next beacon reception period is received. This brings about the effect of storing in the signal storage area. In addition, even when two beacon signals are received during one beacon signal reception period, an effect of storing each beacon signal in a beacon signal storage area to be stored is brought about. Further, all the start positions of the beacon signal reception period or the beacon signal transmission period provided in the frame period may be measured in integers in unit time, and the process for managing the start position of each period is simplified. . Furthermore, since the frame period is corrected based on the reception start position of the beacon signal received earlier than its own beacon signal reception start position, the unit time is set between the start position of the beacon signal reception period and the start position of the beacon signal transmission period. The difference of “1” is generated in the above and the timing at which the beacon signal is transmitted is advanced, thereby reducing the necessity of the correction value when correcting the frame period and the load related to the correction process of the start position of the frame period. It brings about the effect | action of reducing.

  According to a ninth aspect of the present invention, in the wireless communication system that forms an ad hoc wireless communication network by transmitting and receiving beacon signals between wireless communication devices, the wireless communication device saves time in a predetermined unit time. Timekeeping means for timing, frame period storage means for storing a plurality of beacon signal reception periods and a self-beacon transmission period adjacent to a predetermined position for storing a frame period, and a beacon signal for storing a beacon signal The storage means, the storage position specifying means for specifying the position where the beacon signal is stored, and the storage position specifying means receiving the next beacon signal earlier than the time when the start position of the beacon signal reception period is timed. The storage position control means for moving to the position associated with the period, and the start position of the beacon signal reception period is the unit time. When the time is counted as a fraction, the position obtained by rounding down the fraction and adding 1 to the unit time is changed to the start position of the beacon signal reception period, and the start position of the beacon signal transmission period is counted as the fraction. In this case, the start position changing means for changing the position rounded down to the start position of the beacon signal transmission period, and the beacon signal received after the start position of the beacon signal reception period or after the change start position. Reception position storage means for storing information on the reception start position as information on the time measured between the start position of the beacon signal reception period and the reception start position; and the latest delay from the start position of the beacon signal reception period The frame for correcting the start position of the frame period based on the information on the reception start position of the beacon signal received A wireless communication system characterized by comprising a period correcting means. Thus, when a beacon signal to be received in the next beacon signal reception period is received earlier than the start position of the beacon signal reception period is timed, the beacon associated with the next beacon reception period This brings about the effect of storing in the signal storage area. In addition, even when two beacon signals are received during one beacon signal reception period, an effect of storing each beacon signal in a beacon signal storage area to be stored is brought about. Further, all the start positions of the beacon signal reception period or the beacon signal transmission period provided in the frame period may be measured in integers in unit time, and the process for managing the start position of each period is simplified. . Furthermore, since the frame period is corrected based on the reception start position of the beacon signal received later than its own beacon signal reception start position, the unit time is set between the start position of the beacon signal reception period and the start position of the beacon signal transmission period. Effect of reducing the need for correction of the frame period and reducing the load related to the correction process of the start position of the frame period by causing a difference of “1” in the frame and increasing the timing at which the beacon signal is transmitted. Bring.

  According to a tenth aspect of the present invention, there is provided a wireless communication method in a wireless communication device that forms an ad hoc wireless communication network by transmitting and receiving beacon signals to and from another wireless communication device. A procedure for storing a frame period in which a plurality of beacon signal reception periods and a self-beacon transmission period are provided adjacent to predetermined positions, a procedure for storing beacon signals, The procedure for designating the position where the beacon signal is stored and the storage position designating means at a position associated with the next beacon signal reception period earlier than the time when the start position of the beacon signal reception period is timed. If the starting position of the beacon signal reception period is counted as a fraction in the unit time, the fraction is rounded down and the procedure is moved. When the start time of the beacon signal transmission period is changed to the start position of the beacon signal reception period and the start position of the beacon signal transmission period is counted by the fraction, the position where the fraction is rounded down is used as the beacon signal transmission period. And the information on the reception start position of the beacon signal received after the start position of the beacon signal reception period or after the change is changed from the start position of the beacon signal reception period to the reception start position. The start position of the frame period is corrected based on the procedure stored as information related to the time counted until and the information on the reception start position of the beacon signal received most late from the start position of the beacon signal reception period. A wireless communication method comprising the steps of: Thus, when a beacon signal to be received in the next beacon signal reception period is received earlier than the start position of the beacon signal reception period is timed, the beacon associated with the next beacon reception period This brings about the effect of storing in the signal storage area. In addition, even when two beacon signals are received during one beacon signal reception period, an effect of storing each beacon signal in a beacon signal storage area to be stored is brought about. Further, all the start positions of the beacon signal reception period or the beacon signal transmission period provided in the frame period may be measured in integers in unit time, and the process for managing the start position of each period is simplified. . Furthermore, since the frame period is corrected based on the reception start position of the beacon signal received later than its own beacon signal reception start position, the unit time is set between the start position of the beacon signal reception period and the start position of the beacon signal transmission period. Effect of reducing the need for correction of the frame period and reducing the load related to the correction process of the start position of the frame period by causing a difference of “1” in the frame and increasing the timing at which the beacon signal is transmitted. Bring.

  An eleventh aspect of the present invention provides a procedure for measuring time in a predetermined unit time in a wireless communication device that forms an ad hoc wireless communication network by transmitting and receiving a beacon signal with another wireless communication device; A procedure for storing a frame period in which a plurality of beacon signal reception periods and its own beacon transmission period are provided adjacent to a predetermined position, a procedure for storing a beacon signal, and the beacon signal are stored A procedure for designating a position, a procedure for moving the storage location designation means to a position associated with the next beacon signal reception period earlier than a time when the start position of the beacon signal reception period is timed, and When the start position of the beacon signal reception period is counted as a fraction in the unit time, the fraction is rounded down and the unit time is added to one. Is changed to the start position of the beacon signal reception period, and when the start position of the beacon signal transmission period is measured by the fraction, the position where the fraction is discarded is changed to the start position of the beacon signal transmission period. And information regarding the reception start position of the beacon signal received after the start position of the beacon signal reception period or the changed start position was measured from the start position of the beacon signal reception period to the reception start position. The computer executes a procedure stored as information relating to time and a procedure for correcting the start position of the frame period based on information relating to the reception start position of the beacon signal received most late from the start position of the beacon signal reception period. It is a program characterized by making it carry out. Thereby, when a beacon signal to be received in the next beacon signal reception period is received earlier than the start position of the beacon signal reception period is timed, this beacon signal is associated with the next beacon reception period. The beacon signal is stored in the stored beacon signal storage area. In addition, even when two beacon signals are received during one beacon signal reception period, an effect of storing each beacon signal in a beacon signal storage area to be stored is brought about. Further, all the start positions of the beacon signal reception period or the beacon signal transmission period provided in the frame period may be measured in integers in unit time, and the process for managing the start position of each period is simplified. . Furthermore, since the frame period is corrected based on the reception start position of the beacon signal received later than its own beacon signal reception start position, the unit time is set between the start position of the beacon signal reception period and the start position of the beacon signal transmission period. Effect of reducing the need for correction of the frame period and reducing the load related to the correction process of the start position of the frame period by causing a difference of “1” in the frame and increasing the timing at which the beacon signal is transmitted. Bring.

  According to the present invention, when an ad hoc wireless communication network is configured with a plurality of wireless communication devices, the received beacon signal is stored in a predetermined beacon signal storage area even when the wireless communication devices are not synchronized. Based on the difference between the position where the beacon signal is received and the start position of the own beacon signal reception period, and synchronizes the frame period of the self and the frame period of other wireless communication devices constituting the wireless communication network. It can be corrected to take.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram schematically showing a configuration of a wireless communication network according to an embodiment of the present invention. FIG. 1 shows a state where an ad hoc wireless communication network is formed between six wireless communication devices and wireless communication devices around them.

  In FIG. 1, an area indicated by a dotted line centering on each wireless communication device schematically shows a radio wave reachable range of each wireless communication device which is a mobile station. Each wireless communication device can directly perform wireless communication with other wireless communication devices within the radio wave reachable range. In the example illustrated in FIG. 1, the wireless communication device STA0 can directly perform wireless communication with the wireless communication device STA1 within the radio wave reachable range, and the radio communication device STA1 and the radio communication device STA0 and the radio communication within the radio wave reachable range The wireless communication device STA2 can directly perform wireless communication, and the wireless communication device STA2 can directly wirelessly communicate with the wireless communication device STA1 and the wireless communication device STA3 within the radio wave reachable range, and the wireless communication device STA3 can reach the radio wave. The wireless communication device STA2, the wireless communication device STA4, and the wireless communication device STA5 within the range can directly communicate with each other, and the wireless communication device STA4 directly communicates with the wireless communication device STA3 and the wireless communication device STA5 within the radio wave reachable range. Wireless communication is possible, and the wireless communication device STA5 is within the radio wave reachable range. It shows a state is possible direct radio communication apparatus and radio communication device STA4.

  In the example shown in FIG. 1, these wireless communication apparatuses STA0 to STA5 hold a common frame period. Then, by transmitting and receiving beacon signals to each other according to this frame period, it is possible to notify the existence of itself and to recognize the existence of other wireless communication devices, and to perform ad hoc wireless communication between the wireless communication devices STA0 to STA5. it can.

  FIG. 2 shows an example of a functional configuration of radio communication apparatus (STA) 100 in the present embodiment. The radio communication apparatus 100 according to the present embodiment corrects the start position of its own frame period in accordance with the radio communication apparatus 100 that has the latest frame period start position in the radio communication network shown in FIG. It is what I did.

  As illustrated in FIG. 2, the wireless communication apparatus 100 according to the present embodiment includes an antenna 110, a wireless reception unit 111, a reception buffer 112, a beacon signal analysis unit 113, a storage position control unit 114, and a storage position designation. Unit 115, beacon signal storage unit 116, reception start position counter 117, frame cycle storage unit 118, frame cycle management unit 119, timer unit 120, correction value setting unit 121, and frame cycle correction unit 122 , A start position changing unit 123, a timing control unit 124, a beacon signal generating unit 125, a transmission buffer 126, and a wireless transmission unit 127.

  The antenna 110 emits a radio signal to a transmission medium (in the air) or receives a radio signal from the transmission medium.

  The wireless reception unit 111 receives beacon signals and data signals transmitted from other wireless communication devices 100 via the antenna 110 at a predetermined reception timing specified by the timing control unit 124, and performs demodulation processing on these signals. To receive data and temporarily store it in the receive buffer 112.

  The reception buffer 112 temporarily stores the reception data received by the wireless reception unit 111. When the reception data is information addressed to the application device, the reception data is extracted from the reception buffer 112 and is illustrated in FIG. The received data is passed to the external device via the interface unit that does not. Examples of external devices include information processing devices such as personal computers and PDAs (Personal Digital Assistants).

  The beacon signal analysis unit 113 analyzes the beacon signal received via the wireless reception unit 111 and acquires information such as the identifier of the wireless communication device 100 that has transmitted the beacon signal and the reception start position at which the beacon signal is received.

  The storage position control unit 114 controls a storage position specifying unit 115 described below, which will be described later.

  The storage position designation unit 115 designates a position when the beacon signal is stored in the beacon signal storage area, and the received beacon signal is stored at the position designated by the storage position designation unit 115.

  The beacon signal storage unit 116 stores the received beacon signal. As described later, the received beacon signal is associated with a predetermined beacon slot and the identifier or beacon of the wireless communication device 100 that transmitted the beacon signal is stored. The reception start position where the signal is received is stored.

  The reception start position counter 117 is for timing the position at which the beacon signal is received. Timing is started from the start position of the beacon slot according to the timing given from the timing control unit 124, the time measurement is terminated when the beacon signal is received by the wireless reception unit 111, and the measured value is used for the reception start position of the beacon signal. To the beacon signal storage unit 116.

  The frame cycle storage unit 118 stores a common frame cycle in each wireless communication device 100, and each wireless communication device 100 determines the timing for performing wireless communication according to the stored frame cycle.

  The frame cycle management unit 119 manages the start position of the frame cycle and the start position of the beacon slot provided in the frame cycle according to the time counted by the clock unit 120. The beacon slot will be described later.

  The time measuring unit 120 measures time, and measures time that is a reference for the start timing of device operation such as a frame period. Note that the time measuring unit 120 of this embodiment measures time in units of microseconds (μs) as an example.

  The correction value setting unit 121 extracts a beacon signal reception start position stored in the beacon signal storage unit 116 with the largest value, and corrects the start position of the frame period based on the extracted value. The correction value is set, and the set correction value is given to the frame period correction unit 122.

  The frame period correction unit 122 corrects the start position of the frame period based on the correction value extracted by the correction value setting unit 121.

  The start position changing unit 123 changes the start position of a plurality of beacon slots provided in the frame period in a predetermined case.

  The timing control unit 124 designates the timing of the start position of the beacon slot for the wireless reception unit 111 and the wireless transmission unit 127 in accordance with an instruction from the frame period management unit 119. When the start position of the beacon slot is changed by the start position changing unit 123, the timing control unit 124 designates the timing of the start position of the beacon slot according to the changed start position. In addition, the timing control unit 124 gives the timing of the start position of the beacon slot assigned as the beacon signal reception period to the reception start position counter 117, and the reception start position counter 117 from the start position of the beacon slot or the changed start position. The time until the position where reception of the beacon signal is started is counted.

  The beacon signal generation unit 125 notifies the other wireless communication device 100 of the existence of itself, and generates a beacon signal for participating in this ad hoc wireless communication network (see FIG. 1). The beacon signal is generated according to the parameters stored in the beacon signal storage unit 116 based on a predetermined format. The beacon signal includes, for example, information such as an identifier unique to the own wireless communication device 100.

The transmission buffer 126 is a memory for temporarily storing transmission data. If there is transmission data from an external device connected via an interface unit (not shown), the data and the beacon signal generated by the beacon signal generation unit 125 are temporarily stored in the transmission buffer 126.

  The radio transmission unit 127 takes out transmission data such as a beacon signal from the transmission buffer 126, converts it into a radio transmission signal by performing a modulation process, and transmits it via the antenna 110 at a predetermined transmission timing designated by the timing control unit 124. The transmission information is transmitted.

  FIG. 3 schematically shows a configuration example of the frame period used by each wireless communication apparatus 100 in the present embodiment. This frame period is defined by each wireless communication device 100 configuring the wireless communication network cooperating with the wireless communication device 100 existing in the vicinity. Hereinafter, this frame period is referred to as a superframe period.

  The superframe period includes a beacon period and a data transfer period. The superframe period is divided into 256 slots (MAS-0 to MAS-255) having a certain period. Among these, for example, slots MAS-0 to MAS-19 at the beginning of the superframe are allocated in the beacon period, and in this example, the remaining period from slot MAS-20 to slot MAS-255 is the data communication period. It has become.

  During the beacon period, a beacon slot is provided adjacent to a predetermined position for exchanging a predetermined beacon signal with another wireless communication apparatus 100 in the vicinity of each wireless communication apparatus 100 constituting the wireless communication network. It has been. Each wireless communication device 100 transmits its own beacon signal in a beacon slot assigned to itself as a beacon signal transmission period. A beacon slot other than its own beacon signal transmission period is assigned as a beacon signal reception period for receiving a beacon signal transmitted from another wireless communication device 100. Each wireless communication device 100 sets the start position of its own superframe according to the timing timed by the time measuring unit 120 so that the timings of transmission and reception of beacon signals are synchronized with other wireless communication devices 100.

  FIG. 4 shows an example in which three beacon slots (BS) are assigned to one slot (MAS). That is, beacon slots BS-0 to BS-2 are provided in slot MAS-0, and beacon slots BS-3 to BS-5 are provided in slot MAS-1.

  For example, when the beacon slot BS-0 is assigned to the wireless communication apparatus STA0 as a slot for transmitting its own beacon signal, the wireless communication apparatus STA0 is at the timing when the start position of the beacon slot BS-0 is timed by the time measuring unit 120. Send a beacon signal. When the other radio communication apparatuses STA1 to STA4 receive the beacon signal in the beacon slot BS-0 according to the timing counted by their own timing unit 120, the other radio communication apparatuses STA1 to STA4 store the received beacon signal in a predetermined position in the beacon signal storage unit 116.

  FIG. 5 shows a configuration example of a beacon signal storage list 600 provided in the beacon signal storage unit 116. The beacon signal storage list 600 includes items such as “beacon slot number (610)”, “status (620)”, “reception start position (630)”, and “reception content (640)”. The received beacon signal is stored in a table format as a beacon signal storage list 600. The position where the received beacon signal is stored is designated by “pointer (690)”.

  The beacon signal storage list 600 shown in FIG. 5 is configured to store 60 pieces of information according to the number of beacon slots BS-0 to BS-59 provided in the beacon period, for example. Redundant areas for describing information and the like may be added as necessary.

  The “beacon slot number (610)” is associated with the number assigned to each beacon slot, and is set from “0” to “59”. Each item is recorded in association with a beacon slot number. The beacon signal received in each beacon slot is basically recorded at the position of “beacon slot number (610)” corresponding to the beacon slot that received the beacon signal.

  The column “status (620)” is an area in which the presence / absence of reception of a beacon signal in the beacon slot is written. For example, “○” is indicated when a beacon signal is received, “Δ” is indicated when a signal such as a preamble is detected but a beacon signal is not detected, and “X” is indicated when no signal is received. be able to.

  The column “Reception start position (630)” is an area where a position where reception of a beacon signal is started is written. In the present embodiment, this “reception start position (630)” column has a value written only when reception of a beacon signal is started after the start position of the beacon slot. The reception start position is not the time (absolute time) at which the reception of the beacon signal is started, but is measured by the reception start position counter 117 between the start position of the beacon slot that received the beacon signal and the reception start position of the beacon signal. Time, that is, the delay time (ΔT) of the beacon signal is written. Thereby, compared with the case where the reception start time of the beacon signal is managed as an absolute time, according to the present embodiment, it is possible to reduce the amount of information related to the management of the reception start time of the beacon signal. The load can be reduced.

  It should be noted that the correction value setting unit 121 determines the one having the maximum value among the delay times of the beacon signal described in the column “Reception start position (630)” as a correction value for correcting the start position of the superframe period. Extracted. At this time, if it is not necessary to specify the wireless communication apparatus 100 that transmitted the beacon signal with the latest delay from the start position of its own beacon slot, only the maximum value may be stored. As a result, it is not necessary to provide a column of “reception start position (630)” for each “beacon slot number (610)”, so that the amount of information necessary for managing the reception start position of the beacon signal is further reduced. Can be made.

  In the “Received content (640)” column, various information (parameters) obtained by analyzing the received beacon signal is written. Specifically, a device identifier (Device ID) for identifying the wireless communication device 100 that transmitted the beacon signal, a logical address (MAC Address), other payload information (Payload), and the like can be given.

  A “pointer (690)” shown in FIG. 5 designates a position where a beacon signal is written, and functions as the storage position designation unit 115. Further, the “pointer (690)” indicates a position where reference or writing is currently performed when the beacon signal storage list 600 is referred to or when a beacon signal is written in the beacon signal storage list 600. But there is.

  Next, the function of the storage position control unit 114 will be described with reference to FIG.

  When the beacon signal is currently being written to the beacon signal storage list 600, the storage position control unit 114 makes the position of the “pointer (690)” more constant than the start position of the next beacon slot is timed. The position is moved to the position corresponding to the next beacon slot earlier by time DT1. The position where the pointer is moved is referred to as a pointer movement position PT1.

  As shown in FIG. 6A, the pointer movement position PT1 is provided at a position earlier by a certain time DT1 than the start position of the next beacon slot in each beacon slot BS-0 to BS-3. As will be described later, when the start position of the beacon slot is changed by the start position changing unit 123, the pointer movement position PT1 is provided at a position before the changed start position by a predetermined time DT1. Further, the “certain time DT1” for setting the pointer movement position PT1 can be appropriately set, for example, at a time equal to or less than the difference between the beacon slot period length and the beacon signal length.

  In this way, by moving the “pointer (690)” to the position corresponding to the next beacon slot earlier by the fixed time DT1, the beacon signal that has arrived earlier than the start position of the next beacon slot is stored in the beacon signal storage list 600. It can be stored in a position corresponding to the beacon slot that should be stored. Even if two beacon signals are received in one beacon slot because the beacon signal to be received in the next beacon slot has arrived early, each beacon signal should be stored in the original beacon information list. Can be stored in a location.

  The reason why the “pointer (690)” is moved to the position corresponding to the next beacon slot earlier by the predetermined time DT1 is as follows. In the present embodiment, each wireless communication device STA0 to STA4 transmits a beacon signal at a start position of a beacon slot assigned to itself as a beacon signal transmission period using a common superframe period. If the superframe periods of all the wireless communication devices 100 configuring the wireless communication network are synchronized, the timing for transmitting and receiving the beacon signal between the wireless communication devices 100 is synchronized.

  However, in an ad hoc type wireless communication network, since there is no control station for controlling the synchronization of the superframe period, each wireless communication apparatus 100 uses the frame period management unit 119 according to the timing counted by its own clock unit 120. The start position of the super frame will be set. For this reason, the start position of the superframe period differs between the wireless communication devices 100 depending on the accuracy of the timekeeping unit 120 mounted on each wireless communication device 100, and as a result, the transmission / reception timing of the beacon signal may vary. is there.

  For example, FIG. 6B shows the beacon signal reception status of the wireless communication device STA5 that can communicate with the wireless communication devices STA0 to STA4. In the example shown in FIG. 6B, the superframe periods managed by the wireless communication device STA5 and the wireless communication devices STA0 and STA3 are synchronized. For this reason, in the beacon slot BS-0 and the beacon slot BS-3, the wireless communication device STA5 starts receiving beacon signals at the beacon slot start position.

  On the other hand, the start position of the super frame period managed by the wireless communication apparatuses STA1 and STA2 is set later than the super frame period managed by the wireless communication apparatus STA5. For this reason, in the beacon slots BS-1 and BS-2, the wireless communication apparatus STA5 starts receiving beacon signals after the beacon slot start position.

  In addition, the start position of the super frame period managed by the wireless communication apparatus STA4 is set earlier than the super frame period managed by the wireless communication apparatus STA5. For this reason, the wireless communication apparatus STA5 starts receiving the beacon signal transmitted by the wireless communication apparatus STA-4 earlier than the start position of the beacon slot BS-4.

  Here, the period length of each beacon slot is fixed and is set longer than the signal length of the beacon signal. For this reason, in order to identify in which beacon slot the received beacon signal has been received, the start position of the beacon slot is generally used as a reference. That is, when a beacon signal is received at or after the start position of the beacon slot, the beacon signal is identified as a signal received in the beacon slot. However, for example, when the beacon signal arrives earlier than the start position of the beacon slot as in the beacon slot BS-4, the beacon signal to be received in the beacon slot BS-4 by the method based on the start position Cannot be recognized.

  However, as in the present embodiment, the “pointer (690)” moves to a position corresponding to the next beacon slot by a fixed time DT1 earlier than the start position of the next beacon slot is counted, and the next beacon slot is reached. By designating the slot number, the beacon signal that has arrived early can be stored at the position where it should be stored.

  Next, the function of the start position changing unit 123 will be described with reference to FIGS. 7 and 8.

  When the start position of the beacon slot is measured by the time counting unit 120 as a fraction in a predetermined unit time, the start position changing unit 123 changes the position where this fraction is processed to the start position of the beacon slot. In this embodiment, the predetermined unit time is assumed to be μ seconds.

  First, the function of the start position changing unit 123 when a beacon slot is assigned to itself as a beacon signal transmission period will be described with reference to FIG. In the following, a case where the period length of one slot MAS is set to 256 μs will be described as an example.

  In this case, if three beacon slots are assigned to one slot, the period length of each beacon slot is 85.333 μsec. As already described, since the timing unit 120 of the present embodiment measures time in units of microseconds, the start positions of the second and third beacon slots among the three beacon slots assigned to each slot are 85. 333 μs and 170.667 μs, and in the unit time (1 μs) measured by the time measuring unit 120, a fractional part is generated.

  Therefore, as shown in FIG. 7, when a beacon slot is assigned to itself as a beacon signal transmission period, the start position changing unit 123, when the start position of the beacon slot is represented by a fraction, Is changed to the start position Tx1Time of the beacon signal transmission period. That is, among the three beacon slots assigned to each slot, the start position of the first assigned beacon slot (for example, beacon slot BS-0) is represented by an integer (0 μsec), so the start position is not changed. On the other hand, since the start position of the second beacon slot (for example, beacon slot BS-1) is represented by a fraction, the position (85 μsec) rounded down is changed to the start position Tx1Time (BS-1). In addition, since the original start position of the third beacon slot (for example, beacon slot BS-2) is expressed as a fraction, the position (170 μsec) rounded down by the start position changing unit 123 is a new start. It is changed as the position Tx1Time (BS-2).

  On the other hand, as shown in FIG. 8, when a beacon slot is assigned to itself as a beacon signal reception period and the start position of the beacon slot is expressed as a fraction, the fraction is rounded down to a unit time “1”. The added position is changed to the start position Rx1Time of the beacon signal reception period. That is, among the three beacon slots assigned to each slot, the start position of the beacon slot (BS-0) assigned first is represented by an integer (0 μsec), so the start position is not changed. On the other hand, since the start position of the second beacon slot is represented by a fraction, a position (86 μsec) obtained by discarding the fraction and adding 1 μsec is changed to the start position Rx1Time (BS-1). In addition, since the original start position of the third beacon slot is expressed in fractions, the position (171 μsec) obtained by rounding down the fraction and adding 1 μsec is changed to the start position Rx1Time (BS-2). .

  Thus, when the start position of the beacon slot is expressed as a fraction in the time measured by the time measuring unit 120, the start position of each period is changed by changing it to a position timed by an integer by the time measuring unit 120. Can be simplified. In addition, a difference of “1” is generated in the unit time between the start position of the beacon signal reception period and the start position of the beacon signal transmission period, and the timing at which the beacon signal is transmitted is set earlier, thereby starting the beacon slot. When the superframe period is corrected based on the reception start position of the beacon signal received with a delay from the position, the necessity for correction can be reduced, and the load related to the correction process of the start position of the superframe period can be reduced. .

  Next, the function of the frame period correction unit 122 will be described with reference to FIG.

  As shown in FIG. 9, the frame period correction unit 122 superimposes the correction value set based on the delay time based on the reception start position of the beacon signal received most late from the start position of the beacon slot. The start position of the frame period is corrected later. As a result, among the other wireless communication devices 100 configuring the wireless communication network, the wireless communication device in which the start position of the superframe cycle is set later than the start position of the superframe cycle set by the own wireless communication device 100 The start position of its own frame period can be corrected in accordance with 100.

  In the column of “reception start position (630)” of the beacon signal storage list 600, as shown in FIG. 10, the start position changing unit 123 starts the beacon slot as in the beacon slots BS-1 and BS-2. When the position is changed, the delay time of the beacon signal from the changed start position Rx1Time is written. When the start position is not changed as in the beacon slot BS-0, the beacon signal delay time with respect to the original start position is written. When the beacon signal arrives earlier than the start position of the beacon slot, the pointer moves to the next beacon slot number earlier by a certain time as shown in FIG. However, since the beacon signal has not arrived with a delay, information on the reception position for this beacon signal is not written in the “reception position” column of the beacon signal storage list 600. .

  The correction value set by the correction value setting unit 121 is the maximum value among the beacon signal delay times described in “Reception start position (630)” of the beacon signal storage list 600 in the beacon signal storage unit 116. May be used as a correction value, or an integer correction value may be set according to the delay time (ΔT) as shown in FIG.

  In the example shown in FIG. 11, the correction value setting unit 121 sets the correction value as follows. For example, when the delay time of the beacon signal received in the beacon slot (BS-0) in which the start position Rx1Time is not changed indicates the maximum value, the delay time is less than 1 μs as shown in FIG. In this case, the correction value is set to 0, the correction value is set to 1 μs when the delay time is 1 μs or more and less than 2 μs, and the correction value is set to 2 μs or the like when the delay time is 2 μs or more and less than 3 μs.

  When the delay time of the beacon signal received in the beacon slot (BS-1, BS-2) in which the start position Rx1Time is changed indicates the maximum value, as shown in FIGS. 10B and 10C, The correction value when the delay time from the changed start positions Rx1Time (BS-1) and Rx1Time (BS-2) is 0 μs or more and less than 1 μs is 1 μs, or 1 μs or more and less than 2 μs. Is set to 2 μs or the like. Thus, the correction value can be set as appropriate based on the beacon signal received throughout the beacon period and indicating the maximum delay time.

  However, in the above example, even when the difference from the original reception time is less than 1 μsec, 1 μsec is set as the correction value, and there is a problem that the correction processing is activated more than necessary. Therefore, as another embodiment, when the delay time from the changed start positions Rx1Time (BS-1) and Rx1Time (BS-2) is 0 μs or more and less than 1 μs, no correction is performed and the delay time is 1 μm. When the delay time is 2 μs or more and less than 2 μs, the correction value is 1 μs. When the delay time is 2 μs or more and less than 3 μs, the correction value can be set to 2 μs or the like.

  Next, an operation when radio communication apparatus 100 according to the embodiment of the present invention synchronizes its own superframe period with a superframe period managed by another radio communication apparatus 100 will be described with reference to FIG.

  First, it is determined whether or not it is currently a beacon period in a superframe (step S811). If it is within the beacon period (step S811: Y), it is determined whether or not the pointer movement position (pointer movement time) has been reached (step S812). When the pointer movement position is reached (step S812: Y), the “pointer (690)” is moved to the position corresponding to the next beacon slot (step S813), and the process returns to step S811 again. Thereby, the position where the beacon signal is stored is updated to the position corresponding to the next beacon slot.

  On the other hand, if it is not the pointer movement position (step S812: N), it is determined whether or not a fraction occurs at the start position of the next beacon slot (step S814). If no fraction occurs at the start position of the next beacon slot (step S814: N), it is determined whether or not the start position of the next beacon slot has been reached (step S815). When a fraction occurs at the start position of the next beacon slot (step S814: Y), the start position changing unit 123 determines whether the next beacon slot is a beacon signal transmission period or a beacon signal reception period. After a predetermined start position changing process (step S816) is performed, it is determined in step S815 whether or not the changed start position has been reached.

  When the start position of the next beacon slot is reached (step S815: Y), if the beacon slot is a beacon signal transmission period for transmitting its own beacon signal (step S817: Y), there is no other communication. (Step S818: Y), a beacon signal is transmitted according to a predetermined communication method (step S819).

  If the start position is not the next beacon slot (step S815: N), when a beacon signal is received (step S821: Y), the value measured by the reception start position counter 117 is stored in the beacon signal storage list 600. It is described at a predetermined position (step S822), and the content of the received beacon signal is described in the column of “reception content (640)” (step S823).

  When the next beacon slot is the beacon signal reception period (step S817: N), the time until the reception start position counter 117 is activated and the beacon signal is received is counted (step S820). When a beacon signal is received (step S821: Y), the value measured by the reception start position counter 117 is written in a predetermined position in the beacon signal storage list 600 (step S822), and the received beacon signal The content is described in the column “Received content (640)” (step S823).

  The above process is repeated within the beacon period (step S811: Y). On the other hand, if it is determined in step S811 that the beacon period is not reached, it is determined whether or not the beacon period has ended (step S824).

  When it is determined that the beacon period has ended (step S824: Y), a correction value is set by the correction value setting unit 121 (step S825), and the process waits until the end position of the superframe period is reached (step S826). When the end position of the superframe period is reached (step S826: Y), the position where the time corresponding to the correction value set in step S825 is timed is set as the start position of the next superframe period (step S827).

[Second Embodiment]
The wireless communication apparatus 200 according to the second embodiment is managed by the wireless communication apparatus 200 according to the ad hoc wireless communication network shown in FIG. The start position of the super frame period is corrected.

  FIG. 13 shows a functional configuration example of the wireless communication apparatus 200 of the present embodiment. The wireless communication apparatus 200 according to the present embodiment includes an antenna 210, a wireless reception unit 211, a reception buffer 212, a beacon signal analysis unit 213, a storage location control unit 214, a storage location designation unit 215, and a beacon signal storage. Unit 216, reception start position inverse counter 217, frame period storage unit 218, frame period management unit 219, timing unit 220, correction value setting unit 221, frame period correction unit 222, and start position change unit 223. A timing control unit 224, a beacon signal generation unit 225, a transmission buffer 226, and a wireless transmission unit 227.

  Here, the configuration other than the storage position control unit 214, the beacon signal storage unit 216, the reception start position inverse counter 217, the correction value setting unit 221, the frame period correction unit 222, and the start position change unit 223 is the first embodiment. Since it has the same function as that of the embodiment, the same function part name is given and its description is omitted.

  The beacon signal storage unit 216 according to the second embodiment stores a list similar to the beacon signal storage list 600 illustrated in FIG. 5, but the “reception start position (630)” field has a reception start position. A value measured by the inverse counter 217 is stored.

  The reception start position reverse counter 217 measures the reception start position of the beacon signal when the beacon signal arrives earlier than the start position of the beacon slot. The reception start position reverse counter 217 measures the time from the beacon signal reception start position to the start position of the next beacon slot.

  Next, the function of the storage position control unit 214 of the present embodiment will be described with reference to FIG. The storage position control unit 214 according to the present embodiment is configured so that the “pointer (690)” (storage position specifying unit 215) is currently being written in the beacon signal storage list in the beacon signal storage unit 216. Is moved to a position corresponding to the next beacon slot when a certain time DT2 is counted from the start position of the beacon slot. A position to move the pointer is a pointer movement position PT2.

  As shown in FIG. 14, the pointer movement position PT2 is provided at a position where a certain time DT2 is measured from the start position of the beacon slot in each beacon slot BS-0 to BS-3. As will be described later, when the start position of the beacon slot is changed by the start position changing unit 223, the pointer movement position PT2 is provided at a position counted for a certain time DT2 from the changed start position. In addition, the “certain time DT2” for setting the pointer movement position PT2 can be appropriately set to a time that is not less than the signal length of the beacon signal and less than the period length of the beacon slot.

  In this way, the beacon signal arrived earlier than the start position of the next beacon slot by moving the “pointer (690)” to the position corresponding to the next beacon slot earlier than the end position of the beacon slot is timed. Can be stored in a position corresponding to the beacon slot that should be stored in the beacon signal storage list. Even if two beacon signals are received in one beacon slot because the beacon signal to be received in the next beacon slot has arrived early, each beacon signal should be stored in the original beacon information list. Can be stored in a location.

  Next, the function of the start position changing unit 223 according to the second embodiment will be described with reference to FIGS. 15 and 16.

  When the start position of the beacon slot is measured by the time counting unit 220 as a fraction in a predetermined unit time, the start position changing unit 223 changes the position where this fraction is processed to the start position of the beacon slot. In the present embodiment, description will be made below assuming μ seconds as an example of the predetermined unit time.

  First, the function of the start position changing unit 223 when a beacon slot is assigned to itself as a beacon signal transmission period will be described with reference to FIG. In the following, as in the first embodiment, a case where the period length of one slot MAS is set to 256 μs will be described as an example.

  In this case, if three beacon slots are assigned to one slot, the start positions of the second and third beacon slots are 85.333 μsec and 170.667 μsec, respectively, and the unit time (1 μsec) measured by the timer unit 220 The fraction after the decimal point occurs in.

  Therefore, as shown in FIG. 15, when a beacon slot is allocated to itself as a beacon signal transmission period, the start position changing unit 223, when the start position of the beacon slot is represented by a fraction, Is changed to the start position Tx2Time of the beacon signal transmission period. That is, among the three beacon slots assigned to each slot, the start position of the second beacon slot (for example, beacon slot BS-1) is represented by a fraction, so that the fraction is rounded down and added by 1 μs ( 86 μs) is changed to the start position Tx2Time (BS-1). Also, since the original start position of the third beacon slot (for example, beacon slot BS-2) is expressed in fractions, the start position changing unit 223 rounds down the fraction and adds 1 μs (171 μs). ) Is a new start position Tx2Time (BS-2).

  On the other hand, as shown in FIG. 16, when a certain beacon slot is assigned to itself as a beacon signal reception period, if the start position of the beacon slot is expressed as a fraction, the rounded down position is received as a beacon signal. Change to the start position Rx2Time of the period. That is, among the three beacon slots assigned to each slot, the start position of the second beacon slot is expressed as a fraction, so the position (85 μs) rounded down is changed to the start position Rx2Time (BS-1). Is done. In addition, since the original start position of the third beacon slot is expressed as a fraction, the position (170 μsec) obtained by discarding the fraction is changed to the start position Rx2Time (BS-2).

  In this way, when the start position of the beacon slot is expressed as a fraction in the time measured by the time measuring unit 220, the start position of each period is changed by changing it to a position timed by an integer by the time measuring unit 220. Can be simplified. In addition, the start position of the beacon slot is set by causing a difference of “1” in the unit time between the start position of the beacon signal reception period and the start position of the beacon signal transmission period, and setting the timing at which the beacon signal is transmitted later. When the superframe period is corrected based on the reception start position of the beacon signal received earlier than the position, the necessity for correction can be reduced, and the load related to the correction process of the start position of the superframe period can be reduced. .

  Next, the function of the frame period correction unit 222 of this embodiment will be described with reference to FIG.

  As shown in FIG. 17, the frame period correction unit 222 sets the start position of the super frame period by the correction value set based on the reception start position of the beacon signal received earliest than the start position of the beacon slot. It is to correct to. As a result, among the other wireless communication devices 200 constituting the wireless communication network, the wireless communication device in which the start position of the superframe cycle is set earlier than the start position of the superframe cycle set by the own wireless communication device 200 In accordance with 200, the start position of the own frame period can be corrected.

  In the present embodiment, the “reception start position (630)” column of the beacon signal storage list includes a start position changing unit 223 as shown in FIG. 18, as in beacon slots BS-1 and BS-2. When the start position of the beacon slot is changed, the time measured from the reception start position of the beacon signal received after the pointer movement position PT2 to the changed start position Rx2Time is written. When the start position is not changed as in the case of the beacon slot BS-0, the time measured from the position where reception of the beacon signal is started to the original start position of the beacon slot is written. In addition, when a beacon signal arrives within a certain time DT2 from the start position of the beacon slot, information regarding the reception position for this beacon signal is not written in the “reception position” column of the beacon signal storage list. Become.

  In the present embodiment, the correction value set by the correction value setting unit 221 is the beacon signal storage unit 216 that starts receiving beacon signals described in “Reception start position (630)” of the beacon signal storage list. The time measured from the reception start position of the beacon signal that arrives earliest among the positions to the start position of the next beacon slot may be used as a correction value, or may be adjusted according to the time between them as shown in FIG. A numerical correction value may be set.

  In the example shown in FIG. 19, the correction value setting unit 221 sets the correction value as follows. For example, when the beacon signal received before the start position of the beacon slot (BS-0) whose start position Rx2Time is not changed is the beacon signal that has arrived earliest than the start position of the beacon slot, FIG. As shown in (a), when it arrives less than 1 μs earlier than the start position of the beacon slot BS-0, the correction value is 0, and arrives 1 μs or more and less than 2 μs earlier than the start position of the beacon slot BS-0. In this case, the correction value is set to −1 μs, 2 μs or more and less than 3 μs, and the correction value is set to −2 μs or the like.

  In addition, when the beacon signal received earlier than the start position Rx2Time in the beacon slot (BS-1, BS-2) in which the start position Rx2Time is changed is the beacon signal that arrived earlier than the start position of the beacon slot As shown in FIGS. 19B and 19C, correction values when the arrival position is 0 μs or more and less than 1 μs earlier than the changed start positions Rx2Time (BS-1) and Rx1Time (BS-2) are shown. A correction value is set to −2 μsec or the like when it arrives earlier than 1 μsec, 1 μsec or more and less than 2 μsec. As described above, the correction value can be appropriately set based on the reception start position of the beacon signal that arrives earliest from the start position of each beacon slot among the beacon signals received throughout the beacon period.

  However, in the above example, even when the difference from the original reception time is less than −1 μs, −1 μs is set as the correction value, and there is a problem that the correction process is activated more than necessary. Therefore, as another embodiment, when the delay time from the changed start positions Rx1Time (BS-1) and Rx1Time (BS-2) is 0 μs or more and less than 1 μs, no correction is performed and the delay time is 1 μm. When the delay time is 2 μs or more and less than 2 μs, the correction value can be set to −1 μs. When the delay time is 2 μs or more and less than 3 μs, the correction value can be set to −2 μs or the like.

  Next, an operation when radio communication apparatus 200 according to the second embodiment synchronizes its own superframe period with a superframe period managed by another radio communication apparatus 200 will be described with reference to FIG.

  First, it is determined whether or not it is currently a beacon period in a superframe (step S911). If within the beacon period (step S911: Y), it is determined whether or not the pointer movement position (pointer movement time) has been reached (step S912). When the pointer movement position is reached (step S912: Y), the “pointer (690)” is moved to the position corresponding to the next beacon slot (step S913), and then the reception start position reverse counter 217 is activated. (Step S914), it returns to step S911 again. Thereby, the position where the beacon signal is stored is updated to the position corresponding to the next beacon slot, and the reception start position of the beacon signal received between the pointer movement position and the start position of the next beacon slot is counted. It will be.

  On the other hand, if it is not the pointer movement position (step S912: N), it is determined whether or not a fraction occurs at the start position of the next beacon slot (step S915). If no fraction occurs at the start position of the next beacon slot (step S915: N), it is determined whether or not the start position of the next beacon slot is reached (step S916). If a fraction occurs at the start position of the next beacon slot (step S915: Y), the start position changing unit 223 determines whether the next beacon slot is a beacon signal transmission period or a beacon signal reception period. After the predetermined start position changing process (step S917) is performed, it is determined in step S916 whether or not the changed start position has been reached.

  When the start position of the next beacon slot is reached (step S916: Y), if the beacon slot is a beacon signal transmission period for transmitting its own beacon signal (step S918: Y), there is no other communication. (Step S919: Y), a beacon signal is transmitted according to a predetermined communication method (Step S920).

  If it is not the start position of the next beacon slot (step S916: N), when a beacon signal is received (step S921: Y), the value measured by the reception start position reverse counter 217 is the value in the beacon signal storage list. It is described in a predetermined position (step S922), and the content of the received beacon signal is described in the column of “reception content (640)” (step S923).

  When the next beacon slot is a beacon signal reception period (step S918: N), when a beacon signal is received (step S921: Y), the value measured by the reception start position reverse counter 217 is the beacon signal storage list. (Step S922), and the content of the received beacon signal is described in the column “Received content (640)” (Step S923).

  The above process is repeated within the beacon period (step S911: Y). On the other hand, if it is determined in step S911 that the beacon period is not reached, it is determined whether or not the beacon period has ended (step S924).

  When it is determined that the beacon period has ended (step S924: Y), a correction value is set by the correction value setting unit 221 (step S925), and the end position of the superframe period is corrected (step S926). When the end position of the corrected superframe period is reached (step S927: Y), the end position is set as the start position of the next superframe period (step S928).

  The embodiment of the present invention is an example for embodying the present invention and has a corresponding relationship with the invention-specific matters in the claims as shown below, but is not limited thereto. However, various modifications can be made without departing from the scope of the present invention.

  The processing procedure related to the correction of the frame period described in the embodiment of the present invention may be regarded as a method having a series of these procedures, and a program for causing a computer to execute these series of procedures or the program thereof. It may be considered as a recording medium for storing the program.

It is the figure which showed typically the structure of the radio | wireless communication network which concerns on embodiment of this invention. It is the figure which showed the function structural example of the radio | wireless communication apparatus 100 which concerns on 1st Embodiment. It is the figure which showed the structural example of the super-frame period as an example of the frame period stored in the frame period storage part 118. FIG. It is the figure which showed the structural example of the beacon period provided in a super-frame period. It is the figure which showed the example of a structure of the beacon signal storage list | wrist 600 stored in the beacon signal storage part 116. FIG. It is a figure for demonstrating the function of the storage position control part. It is the figure which showed the example by which the starting position of a beacon signal transmission period is changed by the starting position change part 123. FIG. It is the figure which showed the example by which the start position of a beacon signal reception period is changed by the start position change part 123. FIG. It is the figure which showed the example by which the start position of a super-frame period is correct | amended by the frame period correction | amendment part 122. FIG. It is a figure for demonstrating the time measuring method of the position which the beacon signal is stored, and the reception start position of a beacon signal when a beacon signal is received in each beacon slot in a 1st embodiment. It is the figure which showed the example of a setting of the correction value for correct | amending the start position of the super-frame period set by the correction value setting part. It is the flow which showed the process sequence at the time of the radio | wireless communication apparatus 100 correct | amending the start position of a super-frame period. It is the figure which showed the function structural example of the radio | wireless communication apparatus 200 which concerns on 2nd Embodiment. FIG. 6 is a diagram for explaining a function of a storage position control unit 214. It is the figure which showed the example by which the start position of a beacon signal transmission period is changed by the start position change part 223. It is the figure which showed the example by which the start position of a beacon signal reception period is changed by the start position change part 223. It is the figure which showed the example by which the start position of a super-frame period is correct | amended by the frame period correction | amendment part 222. FIG. It is a figure for demonstrating the time measuring method of the position which the beacon signal is stored, and the reception start position of a beacon signal when a beacon signal is received in each beacon slot in a 2nd embodiment. It is the figure which showed the example of a setting of the correction value for correct | amending the start position of the super-frame period set by the correction value setting part 221. FIG. It is the flow which showed the process sequence at the time of the radio | wireless communication apparatus 200 correct | amending the start position of a super-frame period.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Wireless communication apparatus 110 Antenna 111 Radio | wireless receiving part 112 Reception buffer 113 Beacon signal analysis part 114 Storage position control part 115 Storage position designation | designated part 116 Beacon signal storage part 117 Reception start position counter 118 Frame period storage part 119 Frame period management part 120 Timekeeping Unit 121 correction value setting unit 122 frame period correction unit 123 start position change unit 124 timing control unit 125 beacon signal generation unit 126 transmission buffer 127 wireless transmission unit 200 wireless communication device 210 antenna 211 wireless reception unit 212 reception buffer 213 beacon signal analysis unit 214 Storage position control section 215 Storage position designation section 216 Beacon signal storage section 217 Reception start position reverse counter 218 Frame period storage section 219 Frame period management section 220 Time counting section 21 Correction value setting unit 222 Frame period correction unit 223 Start position change unit 224 Timing control unit 225 Beacon signal generation unit 226 Transmission buffer 227 Radio transmission unit 600 Beacon signal storage list 610 Beacon slot number 620 Status 630 Reception start position 640 Reception content 690 Pointer MAS slot BS Beacon slot DT1 Fixed time DT2 Fixed time PT1 Pointer moving position PT2 Pointer moving position Rx1Time Beacon signal reception period start position Rx2Time Beacon signal reception period start position Tx1Time Beacon signal transmission period start position Tx2Time Beacon signal transmission period start position

Claims (8)

In a wireless communication device that constitutes an ad hoc wireless communication network by transmitting and receiving beacon signals with other wireless communication devices,
A time measuring means for measuring time;
A frame period storage means for storing a frame period in which a plurality of beacon signal reception periods are provided adjacent to a predetermined position;
Beacon signal storage means for storing beacon signals;
Storage position specifying means for specifying a position where the beacon signal is stored;
No line start position of the beacon signal receiving period it and a storage position control means for moving fast the storage position specifying means by a predetermined time at a position associated with the next beacon signal reception period than is timed Communication device. The frame period stored in the frame period storage means includes its own beacon signal transmission period,
When the start position of the beacon signal reception period is counted as a fraction in the unit time, the position obtained by rounding down the fraction and adding the unit time to 1 is changed to the start position of the beacon signal reception period, and the beacon signal When the start position of the transmission period is timed by the fraction, start position changing means for changing the position rounded down to the start position of the beacon signal transmission period;
Claim 1, further comprising a frame period correcting means for correcting the start position of the frame period based on the received starting position of the beacon signals received later than the start position after the start position or change of the beacon signal reception period The wireless communication device described Reception in which information related to the reception start position of the beacon signal received after the start position of the beacon signal reception period is stored as information related to the time measured between the start position of the beacon signal reception period and the reception start position Position storage means;
2. The wireless communication according to claim 1 , further comprising: a frame period correction unit that corrects a start position of the frame period based on information related to a reception start position of a beacon signal received most late from a start position of the beacon signal reception period. apparatus. The reception in the position storage unit, the beacon signal reception period of the start position slowest only information about the reception start position of the received beacon signal is a radio communication apparatus is Ru請 Motomeko 3 wherein storing more. In a wireless communication device that constitutes an ad hoc wireless communication network by transmitting and receiving beacon signals with other wireless communication devices,
A time measuring means for measuring time in a predetermined unit time;
A frame period storage means for storing a frame period in which a plurality of beacon signal reception periods and a self-beacon transmission period are provided adjacent to a predetermined position;
Beacon signal storage means for storing beacon signals;
Storage position specifying means for specifying a position where the beacon signal is stored;
Storage position control means for moving the storage position specifying means to a position associated with the next beacon signal reception period earlier than a time when the start position of the beacon signal reception period is timed,
When the start position of the beacon signal reception period is counted as a fraction in the unit time, the position obtained by rounding down the fraction and adding the unit time to 1 is changed to the start position of the beacon signal reception period, and the beacon signal When the start position of the transmission period is timed by the fraction, start position changing means for changing the position rounded down to the start position of the beacon signal transmission period;
Information related to the reception start position of the beacon signal received after the start position of the beacon signal reception period or the changed start position is related to the time measured from the start position of the beacon signal reception period to the reception start position Receiving position storage means stored as information;
The beacon signal reception period of the start position slowest radio communications device you and a frame period correcting means for correcting the start position of the frame period based on the information on the reception start position of the received beacon signal from the. In a wireless communication system constituting an ad hoc wireless communication network by transmitting and receiving beacon signals between wireless communication devices,
The wireless communication device
A time measuring means for measuring time in a predetermined unit time;
A frame period storage means for storing a frame period in which a plurality of beacon signal reception periods and a self-beacon transmission period are provided adjacent to a predetermined position;
Beacon signal storage means for storing beacon signals;
Storage position specifying means for specifying a position where the beacon signal is stored;
Storage position control means for moving the storage position specifying means to a position associated with the next beacon signal reception period earlier than a time when the start position of the beacon signal reception period is timed,
When the start position of the beacon signal reception period is counted as a fraction in the unit time, the position obtained by rounding down the fraction and adding the unit time to 1 is changed to the start position of the beacon signal reception period, and the beacon signal When the start position of the transmission period is timed by the fraction, start position changing means for changing the position rounded down to the start position of the beacon signal transmission period;
Information related to the reception start position of the beacon signal received after the start position of the beacon signal reception period or the changed start position is related to the time measured from the start position of the beacon signal reception period to the reception start position Receiving position storage means stored as information;
The beacon signal reception period radio communications system that includes a frame period correcting means for correcting the start position of the frame period based on the information on the reception start position of the most delayed beacon signal received from the start position of the. In a wireless communication method in a wireless communication device that forms an ad hoc wireless communication network by transmitting and receiving a beacon signal with another wireless communication device,
A procedure for measuring time in a predetermined unit time;
A procedure for storing a frame period in which a plurality of beacon signal reception periods and a self-beacon transmission period are provided adjacent to a predetermined position;
Procedures for storing beacon signals;
Specifying the location where the beacon signal is stored;
A procedure for moving the storage position specifying means to a position associated with the next beacon signal reception period earlier than a time when the start position of the beacon signal reception period is timed,
When the start position of the beacon signal reception period is counted as a fraction in the unit time, the position obtained by rounding down the fraction and adding the unit time to 1 is changed to the start position of the beacon signal reception period, and the beacon signal When the start position of the transmission period is timed by the fraction, a procedure for changing the truncated position to the start position of the beacon signal transmission period;
Information related to the reception start position of the beacon signal received after the start position of the beacon signal reception period or the changed start position is related to the time measured from the start position of the beacon signal reception period to the reception start position Procedures stored as information,
Radio communications how to and a procedure for correcting the start position of the frame period based on the information on the reception start position of the most delayed beacon signal received from the start position of the beacon signal reception period. In a wireless communication device that constitutes an ad hoc wireless communication network by transmitting and receiving beacon signals with other wireless communication devices,
A procedure for measuring time in a predetermined unit time;
A procedure for storing a frame period in which a plurality of beacon signal reception periods and a self-beacon transmission period are provided adjacent to a predetermined position;
Procedures for storing beacon signals;
Specifying the location where the beacon signal is stored;
A procedure for moving the storage position specifying means to a position associated with the next beacon signal reception period earlier than a time when the start position of the beacon signal reception period is timed,
When the start position of the beacon signal reception period is counted as a fraction in the unit time, the position obtained by rounding down the fraction and adding the unit time to 1 is changed to the start position of the beacon signal reception period, and the beacon signal When the start position of the transmission period is timed by the fraction, a procedure for changing the truncated position to the start position of the beacon signal transmission period;
Information related to the reception start position of the beacon signal received after the start position of the beacon signal reception period or the changed start position is related to the time measured from the start position of the beacon signal reception period to the reception start position Procedures stored as information,
The beacon signal slowest to execute a procedure for correcting the computer start position of the frame period based on the information on the reception start position of the received beacon signal Help program from the start position of the reception period.

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