JP5413269B2 - Wireless communication apparatus, wireless communication method and program - Google Patents

Description

  The present invention is a wireless communication apparatus that can be used in a wireless system that includes a parent wireless terminal that transmits a beacon signal and one or more child wireless terminals that receive the beacon signal and synchronize with the parent wireless terminal. The present invention relates to a wireless communication apparatus capable of optimizing the time for wireless communication and reducing power consumption for communication.

  There is a communication system in which a parent wireless terminal and a child wireless terminal perform an intermittent reception operation asynchronously without synchronizing their respective clocks. In such a communication system that performs intermittent reception asynchronously, it is necessary to transmit a preamble signal that is longer than the intermittent reception cycle of the communication partner because it is not known at which timing the communication partner is waiting for reception. For example, when the intermittent reception period is 2 seconds, the preamble signal needs to have a length of 2 seconds or more. Patent Document 1 is an example of a wireless communication system that performs intermittent reception asynchronously with such a communication partner.

  According to Patent Literature 1, a signal having a short preamble signal is transmitted when the communication partner is continuously receiving, and a preamble signal longer than the intermittent reception of the communication partner is transmitted when the communication partner is intermittently receiving. It is described to do. And it is described not to simply lengthen the preamble signal, but to make the signal frame composed of the preamble signal, the frame synchronization signal and the control signal to be longer than the intermittent reception cycle a plurality of times. . That is, it is described that the signal frame is not repeated when the communication partner is continuously receiving and that the number of repetitions is increased when the communication partner is intermittently receiving.

  On the other hand, a communication system including a parent wireless terminal that transmits a beacon is used in a wireless network system provided by a wireless LAN or a fixed wireless access (FWA) provider. In the wireless network, the child wireless terminal periodically receives a beacon signal transmitted from the parent wireless terminal, and synchronizes its own clock with the clock of the parent wireless terminal. A time position for transmitting and receiving data is determined based on the beacon signal, and the parent wireless terminal and the child wireless terminal communicate at the determined time position.

  The interval at which the child radio terminal periodically receives the beacon signal is at most about several seconds at most. In other words, since the clock synchronization between the parent wireless terminal and the child wireless terminal is performed in several seconds, the time error between the timing when the child wireless terminal goes to receive the beacon signal and the timing when the parent wireless terminal transmits the beacon signal is very small. . For example, if the beacon reception interval of the child radio terminal is 2 seconds and the clock error of the child radio terminal and the parent radio terminal is 100 ppm, the clock error time at the reception interval of 2 seconds is as very small as 0.2 msec. Since the clocks of the parent wireless terminal and the child wireless terminal are always synchronized every 2 seconds, the maximum clock error time between the parent wireless terminal and the child wireless terminal is 0.2 milliseconds. Therefore, the relative error of the time position at which the parent wireless terminal and the child wireless terminal perform data communication is also as small as 0.2 ms at maximum. In other words, the maximum error between the transmission timing on the transmission side and the reception timing on the reception side is as small as 0.2 msec. Therefore, if the preamble of the transmission signal is increased by about 0.2 msec, the preamble of the transmission signal can always be received on the reception side. Therefore, there is no problem in communication. Therefore, the signal frame described in Patent Document 1 is not repeatedly transmitted.

JP 2007-208442 A

  However, in a communication system consisting of a parent wireless terminal that transmits a beacon, a request to reduce power consumption to the utmost limit is made, the beacon signal transmission interval is increased, or the beacon signal transmission interval is short. It may be possible to lengthen the beacon reception for receiving the beacon signal and setting the clock to the parent wireless terminal. For example, consider a system in which a beacon reception interval of a child wireless terminal is performed every 512 seconds, and intermittent reception for receiving data from a parent wireless terminal is performed every 4 seconds obtained by dividing the 512 seconds into 128. In such a system, the child radio terminal captures a beacon signal from the parent radio terminal and performs clock adjustment every 512 seconds. Therefore, assuming that the clock error between the clock of the child radio terminal and the parent radio terminal is 100 ppm, the maximum clock error time at the reception interval of 512 seconds is as large as 51.2 ms. When the parent wireless terminal performs data communication with the child wireless terminal, in order to absorb the maximum clock error time of 51.2 milliseconds at the timing of every 4 seconds that the child wireless terminal is waiting for reception, Patent Document 1 In the method described in the above, a method of repeatedly transmitting a signal frame composed of a preamble signal, a frame synchronization signal, and a control signal over a time of 51.2 milliseconds or more can be considered, but the repetition time of the signal frame is long and power consumption increases. There was a problem.

  The present invention solves the above-described conventional problems, and provides a wireless communication apparatus, a wireless communication method, and a program capable of suppressing an increase in power consumption even if the beacon reception interval is increased by a simple configuration and method. For the purpose.

  A communication partner periodically transmits a beacon signal for synchronizing transmission / reception timing, and when information to be transmitted is generated, a data signal is transmitted after a plurality of repeated frames including an identification code at the reception timing of the communication partner. In the wireless communication apparatus configured to transmit the present frame including the timing according to the time difference between the timing at which the information to be transmitted occurs and the timing at which the communication partner receives the beacon signal to perform synchronization correction This is a wireless communication apparatus configured to make the number of repeated frame transmissions variable.

  And since the number of times of transmission of the repetitive frame is variable according to the time difference from the timing of receiving the beacon signal for the communication partner to perform synchronization correction, the optimum number of times of repetitive frame transmission can be set and power consumption is increased. Can be suppressed.

  In a communication system including a parent wireless terminal that transmits a beacon by using the wireless communication device, the wireless communication method, and the program according to the present invention, the child wireless terminal receives the beacon and synchronizes with the clock of the parent wireless terminal. Even if the interval is long, an increase in power consumption can be suppressed.

The block diagram of the radio | wireless communication apparatus in 1st embodiment of this invention 1 is a configuration diagram of a wireless communication system using a wireless communication device according to a first embodiment of the present invention. The figure which shows the slot structure in 1st embodiment of this invention. The figure which shows the slot relationship between each radio | wireless terminal in 1st embodiment of this invention. The figure which shows the signal format of the link connection signal in 1st embodiment of this invention The figure which shows the reception carrier sense timing of the child radio | wireless terminal in 1st embodiment of this invention

  According to a first aspect of the present invention, a communication partner periodically transmits a beacon signal for synchronizing transmission / reception timing, and when information to be transmitted is generated, a repeated frame including an identification code is received a plurality of times at the reception timing of the communication partner. In the wireless communication device configured to transmit the present frame including the data signal after transmission, the timing at which the information to be transmitted occurs and the timing at which the communication partner receives the beacon signal to perform synchronization correction The wireless communication apparatus is configured to vary the number of times the repeated frame is transmitted according to the time difference.

  And since the number of times of transmission of the repetitive frame is variable according to the time difference from the timing of receiving the beacon signal for the communication partner to perform synchronization correction, the optimum number of times of repetitive frame transmission can be set and power consumption is increased. Can be suppressed.

  A second invention is a wireless communication apparatus configured to change a timing at which transmission of the repetitive frame is started according to the number of transmissions.

  The timing for starting the transmission of the repetitive frame can be changed according to the number of transmissions, so that the intermittent reception timing of the communication partner always comes somewhere in the repetitive frame even if there is a clock error between the transmitting side and the receiving side. Can be optimized.

  In a third aspect of the invention, the beacon signal transmitted from the wireless communication device of the first aspect of the invention is periodically received, the reception timing is corrected, and the beacon signal is periodically received at an interval of 1 / m. A wireless communication apparatus that performs a reception operation, and performs a reception operation at the 1 / m interval according to a time difference between a timing at which the beacon signal is periodically received and a timing at which the reception operation is performed at the 1 / m interval. A wireless communication device configured to change a timing position.

  Then, by changing the timing position at which the reception operation is performed at the 1 / m interval, it is possible to always receive somewhere in the repetitive frame even if there is a clock error between the transmission side and the reception side.

  According to a fourth aspect of the present invention, there is provided a step in which a communication partner periodically transmits a beacon signal for synchronizing transmission / reception timing, and a repetitive frame including an identification code at the reception timing of the communication partner when information to be transmitted occurs. In the wireless communication method, comprising performing a step of transmitting a plurality of times and a step of transmitting the frame including a data signal after executing the step of transmitting the plurality of times, a timing at which the information to be transmitted occurs and the communication partner are synchronized In order to perform correction, the number of times of transmission of the repetitive frame is controlled in the step of transmitting the repetitive frame by the step of changing the number of times of transmission of the repetitive frame according to the time difference with the timing of receiving the beacon signal. A wireless communication method.

  And since the number of times of transmission of the repetitive frame is variable according to the time difference from the timing of receiving the beacon signal for the communication partner to perform synchronization correction, the optimum number of times of repetitive frame transmission can be set and power consumption is increased. Can be suppressed.

  According to a fifth aspect of the present invention, in the wireless communication method according to the fourth aspect, the timing for transmitting the repetitive frame is changed according to the number of transmissions.

  The timing for starting the transmission of the repetitive frame can be changed according to the number of transmissions, so that the intermittent reception timing of the communication partner always comes somewhere in the repetitive frame even if there is a clock error between the transmitting side and the receiving side. Can be optimized.

  In a sixth aspect of the invention, the beacon signal transmitted from the wireless communication method of the fourth aspect of the invention is periodically received, the reception timing is corrected, and the beacon signal is periodically received at an interval of 1 / m. A wireless communication method for performing a reception operation, wherein the reception operation is performed at an interval of 1 / m in accordance with a time difference between a timing of periodically receiving the beacon signal and a timing of performing the reception operation at an interval of 1 / m. A wireless communication method configured to change a timing position.

  And since the number of times of transmission of the repetitive frame is variable according to the time difference from the timing of receiving the beacon signal for the communication partner to perform synchronization correction, the optimum number of times of repetitive frame transmission can be set and power consumption is increased. Can be suppressed.

  Since the seventh invention is a program for causing a computer to realize at least a part of the wireless communication apparatus or the wireless communication method according to any one of the first to sixth aspects of the invention, an electrical / information device, a computer, By cooperating hardware resources such as the above, at least a part of the present invention can be realized by simple hardware. In addition, the program can be distributed / updated and installed easily by recording on a recording medium or distributing the program using a communication line.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
A first embodiment of the present invention will be described. FIG. 1 shows an example of a wireless communication apparatus of the present invention. FIG. 1A is a block diagram of the parent wireless terminal, and FIG. 1B is a block diagram of the child wireless terminal.

  First, an outline of the configuration of the parent wireless terminal will be described with reference to FIG. 1 is an antenna, 2 is a transmission / reception means, 3 is a beacon transmission means, 4 is a beacon transmission control means, 5 is a link connection means, 6 is a repeat frame number setting means, and 7 is a control means. The control means 7 performs time management of the entire wireless communication apparatus and control of each means. The transmission / reception means 2 includes a wireless transmission / reception circuit for performing wireless communication via the antenna 1.

  Next, an outline of the configuration of the child radio terminal will be described with reference to FIG. 11 is an antenna, 12 is a transmission / reception unit, 13 is a beacon reception unit, 14 is a beacon reception control unit, 15 is a carrier sense unit, 16 is a link connection unit, and 17 is a control unit. The control means 17 performs time management of the entire wireless communication apparatus and control of each means. The transmission / reception means 12 includes a wireless transmission / reception circuit for performing wireless communication via the antenna 11.

  FIG. 2 is a diagram showing a wireless communication system using the wireless communication apparatus shown in FIG. The parent wireless terminal 101 is the wireless communication apparatus shown in FIG. 1A, and the child wireless terminals 102, 103, 104, 202, 203, 204, 302, 303, and 304 are wireless communication apparatuses shown in FIG. is there. The relay wireless terminals 201, 301, and 401 have the functions of both FIG. 1 (a) and FIG. 1 (b).

  The outline of the operation of the communication system using the wireless communication apparatus of FIG. 1 will be described with reference to FIG. The parent wireless terminal 101 can directly communicate with the child wireless terminals 102, 103, and 104, but cannot communicate directly with the child wireless terminal 202 or the like due to poor radio wave conditions. Therefore, communication is performed with the slave wireless terminals 202, 203, and 204 via the relay terminal 201. Further, the slave radio terminals 302, 303, and 304 communicate with each other via the relay radio terminal 201 and further via the relay radio terminal 301. The parent wireless terminal 101 periodically transmits a clock adjustment signal called a beacon signal, and the child wireless terminal 102 or the relay wireless terminal 201 directly connected to the parent wireless terminal periodically captures the beacon signal. Synchronize with the clock of the parent wireless terminal 101. Here, the parent wireless terminal 101 is defined as a host device, and the child wireless terminal 102 and the relay wireless terminal 201 that are directly connected to the parent wireless terminal 101 that is the host device are defined as lower devices.

  Similarly, the relay wireless terminal 201 works as a parent wireless terminal and the relay wireless terminal 201 periodically transmits a beacon signal for clock adjustment to the child wireless terminal 202 and the like, and is directly connected to the relay wireless terminal 201. The child radio terminal 202, the relay radio terminal 301, and the like periodically capture the beacon signal and synchronize with the clock of the relay radio terminal 201. The upper device is the relay wireless terminal 201, and the lower devices are the child wireless terminal 202 and the relay wireless terminal 301 that are directly connected to the relay wireless terminal 201.

  The wireless communication apparatus of the present invention shown in FIG. 1 is configured to perform communication by dividing a time axis into a plurality of slots. FIG. 3A shows a basic slot configuration managed by the wireless communication apparatus of FIG. The basic slot is composed of T1 seconds, and this basic slot is repeated on the time axis. The basic slot length T1 is, for example, 2 seconds. The basic slot is further composed of two slots, a lower slot and an upper slot. Each of the lower slot length and the upper slot length is half the time of T1. The lower slot is a slot for communicating with the lower apparatus, and the upper slot is a slot for communicating with the upper apparatus. The lower slot is further divided into three slots, slot 21, slot 22, and slot 23. The slot 21 is a beacon transmission slot (BT), the slot 22 is a link connection slot (L), and the slot 23 is a data communication slot (D). Similarly, the upper slot is further divided into three slots 24, 25, and 26. The slot 24 is a beacon receiving slot (BR), the slot 25 is a link connection slot (L), and the slot 26 is a data communication slot (D).

  The host device periodically transmits a beacon signal using the beacon transmission slot (BT) of the slot 21. The beacon signal may always be transmitted in a beacon transmission slot (BT), or may be transmitted every plural slots. If the beacon signal is set to be transmitted every two beacon transmission slots (BT), T1 = 2 seconds and the beacon transmission interval is 4 seconds.

  The lower device periodically receives a beacon signal from the higher device in the beacon receiving slot (BR) of the slot 24. The interval for receiving the beacon signal can be set to an integral multiple of the beacon signal transmission interval. For example, if it is set to 256 times the beacon transmission interval of 2 seconds, the beacon reception interval is 8 minutes and 32 seconds.

  The link connection slot (L) between the slot 22 and the slot 25 is a slot in which the upper device and the lower device communicate for link connection. The slot (D) for data communication of the slot 23 and the slot 26 is a slot for performing communication for exchanging data after link connection between the upper device and the lower device.

  The link connection slot (L) of the slot 22 and the slot 25 is composed of two slots, a slot 27 and a slot 28, as shown in FIG. Slot 27 is a lower call slot, and slot 28 is a higher response / higher call slot. The lower call slot is a slot for the lower device to transmit a link connection request signal when it is desired to establish a link connection from the lower device. The higher response / upper call slot is a slot for a higher device to return a response to a link connection request signal from a lower device, or a higher device requests a link connection request signal when link connection is desired from the upper device. Is a slot for transmitting. T2 is the slot length of the lower call slot 27, and T3 is the slot length of the higher response / upper call slot 28.

  FIG. 4 is a diagram illustrating a slot position relationship among the parent wireless terminal 101, the relay wireless terminal 201, the relay wireless terminal 301, and the child wireless terminal 302. (A) is a slot managed by the parent radio terminal 101, (b) is a slot managed by the relay radio terminal 201, (c) is a slot managed by the relay radio terminal 301, and (d) is a slot managed by the child radio terminal 302. Indicates the slot to be managed. As shown in the slot 33 in the slot of FIG. 4, the notation “lower” indicates the lower slot of FIG. Similarly, as shown in the slot 34, the notation “upper” indicates the upper slot in FIG. A slot 32 is a basic slot composed of a slot 33 and a slot 34. Then, slot numbers 1 to 256 are assigned to the basic slots in order, and the slot number 256 is followed by the slot number 1.

  In FIG. 4, 31 indicates a beacon signal. In FIG. 4, a beacon signal is transmitted from a beacon transmission slot in a lower slot of every other basic slot. Therefore, the beacon transmission interval T5 = 2 × T1. If T1 = 2 seconds, then T5 = 4 seconds. The beacon signal transmitted from the parent wireless terminal 101 is periodically received by the relay wireless terminal 201. The relay wireless terminal 201 is configured to receive the beacon signal 31 transmitted from the slot number 1 of the parent wireless terminal 101. Beacon signal 31 is loaded with beacon number 1 corresponding to slot number 1. When the relay wireless terminal 201 receives the beacon signal 31 with the beacon number 1, the head position of the lower slot of the basic slot number 1 of the parent wireless terminal 101 becomes the head position of the upper slot of the basic slot number 255 of the relay wireless terminal 201. Reconfigure the slots. Then, the relay radio terminal 201 transmits a beacon signal at the odd-numbered basic slot number, like the parent radio terminal 101. In the same operation, the lower device receives the beacon signal transmitted from the basic slot number 1 of the higher device, and reconfigures its own slot in synchronization with the timing of the higher device. Since the interval T4 for receiving the beacon signal of the host device is every 256 basic slots, T4 = 8 minutes 32 seconds. In FIG. 4, beacon reception is performed in a beacon reception slot (BR) among the upper slots whose slots are painted black. Note that no beacon signal is transmitted because there is no lower-level device connected to the child radio terminal 302.

  A case where the parent wireless terminal 101 wants to send data to the child wireless terminal 302 will be described. The relay radio terminals 201 and 301 perform the reception carrier sense operation in the higher call slot 28 (see FIG. 3) among all the higher slots. In the reception carrier sense operation, it is detected whether the reception level is equal to or higher than a predetermined level. If the reception level is lower than the predetermined level, the reception carrier sense operation is stopped and a standby state is entered. If the level is equal to or higher than the predetermined level, a link connection signal is received from the host device. Therefore, when a data transmission request addressed to the child wireless terminal 302 is generated at the time of slot number 5, for example, the parent wireless terminal 101 transmits a link connection signal in the higher call slot 28 in the lower slot of the slot number 6.

  The repeater 201 performs reception carrier sense in the higher call slot 28 in the higher slot of the slot number 4 and receives the link connection signal from the parent radio terminal 101 after performing carrier sense.

  The message format of the link connection signal is shown in FIG. The link connection signal is composed of n repetitive frames 41 to 46 and a main body frame. FIG. 5B shows the configuration of the repetitive frame. The repetitive frame identifies a bit synchronization signal 48 for determining a bit sampling position, a frame synchronization signal 49 for detecting the head of data included in the frame, a control signal 50 carrying various control information and a device. The identification code (hereinafter referred to as ID) is a simplified ID. The ID is, for example, 64 bits, and the simple ID is 16 bits obtained by dividing the ID into four. Information on which 16 bits of the ID divided into four are used as the simple ID 51 is in the control signal 50. The repetitive frame length is T6. Therefore, n repetitive frame lengths T7 are T7 = n × T6. Repetitive frames 41 to 46 are given repetitive frame numbers 1 to n, and the repetitive frame number is added to the control signal 50. The repeated frame is transmitted from a repeated frame having a large repetition number as shown in FIG. 1A, and the repeated frame number is decremented one by one, and the repeated frame number immediately before the main frame is 1.

  FIG. 6 is a diagram for explaining the reception carrier sense timing. FIG. 6A shows a link connection signal transmitted from the host device. FIG. 6B is a diagram illustrating the carrier sense timing of the lower device that receives the carrier connection sense of the link connection signal transmitted from the higher device. 6B, (b-1) shows a case where the clocks of the upper device and the lower device are not shifted, and FIGS. 6B, 6B-2 show that the clock of the lower device is advanced relative to the clock of the upper device. 6 (b) and 6 (b-3) show a case where the clock of the lower device is delayed with respect to the clock of the higher device. Reference numeral 50 denotes the head position of the upper call slot of the lower device. Reference numeral 51 denotes the reception carrier sense timing of the lower device. The reception carrier sense timing is set to T8 = T7 / 2 from the head position 50 of the higher calling slot. With this setting, if the clock deviation ΔT between the upper device and the lower device is in the range of −T8 <= ΔT <= T8, as shown in FIG. Receive carrier sense can be performed somewhere and the main frame can be received.

  If the maximum relative error of the clocks of the upper device and the lower device is set to ± 100 ppm, and the lower device performs clock adjustment every T4 = 512 seconds as shown in FIG. 4, the clocks of each other are shifted by a maximum of ± 51.2 ms. Become. Accordingly, if the number n of repeated transmissions of the link connection signal is set so that T8> = 51.2 ms, no reception failure occurs. However, in FIG. 4, when a data transmission request addressed to the child wireless terminal 302 is generated at the parent wireless terminal 101 at the time of slot number 5, for example, the link connection signal is transmitted in the higher call slot 28 in the lower slot of slot number 6. Send. The repeater 201 performs reception carrier sense in the higher call slot 28 in the higher slot of slot number 4 and receives the link connection signal from the parent radio terminal 101 after carrier sense. Since the relay wireless terminal 201 which is a device performs clock adjustment at the timing of the beacon signal 31, there is almost no clock error at the position of slot number 4. Therefore, it is wasteful to transmit the link connection signal repeated frame transmission times considering 51.2 ms, which increases power consumption. Therefore, the number of repeated frame transmissions in the link connection signal is made variable according to the time from the time when the clock is adjusted with the beacon signal 31 to the timing when the reception carrier sense is performed. For example, since the time from the time when the clock is adjusted with the beacon signal 31 to the timing when the reception carrier sense is performed has a correlation with the slot number, the number of transmissions of the repeated frame in the link connection signal is made variable according to the slot number. . When the parent wireless terminal 101 transmits a link connection signal with the slot number x, the parent wireless terminal 101 sets the number of repeated frame transmissions so that T7> = x / 256 × (± 51.2 ms). When a link connection signal is transmitted at the position of slot number 4, since T7> = ± 0.8 ms, when the repetitive frame length T6 is longer than 0.8 ms, the number of repetitive transmissions may be one or more.

  When the number of repeated frame transmissions is variable, the time T7 in FIG. 6 is also variable. Accordingly, if T8 which is the reception carrier sense timing is fixed, the carrier sense timing 51 does not come to the center of T7 when the clock error ΔT = 0 between the parent radio terminal 101 and the relay radio terminal 201. This means that there is a difference in tolerance of the error range between when the clock error ΔT is positive and when it is negative, which is not preferable. Therefore, when the clock error ΔT = 0, the reception carrier sense timing time T8 is set to be variable in conjunction with T7 so that the carrier sense timing 51 comes to the center of T7 so that T8 = T7 / 2. T7 can be known from the slot number. That is, it is assumed that the slot number position where reception carrier sense is performed is x when converted to the slot number of the parent wireless terminal 101. In this case, it can be seen that T7 of the link connection signal is T7> = x / 256 × (± 51.2 ms).

  In the above description, the example in which T8 is varied by the slot number has been described. T8 can be set to a fixed value, and instead, the link connection signal transmission start position shown in FIG. 6A can be made variable. The link connection signal from the higher-level device is transmitted in the higher-order call slot 28 in the slot 22 of FIG. 3A, and the timing for starting transmission of the link connection signal is made variable according to the slot number. When the slot number becomes larger, T7 becomes larger. Therefore, the timing for starting transmission of the link connection signal is advanced so that the center of T7 comes to the position of the reception carrier sense timing 51.

  The data communication request generated in the slot number 5 of the parent wireless terminal 101 by the above-described operation performs link connection and data communication with the relay wireless terminal 201 in the slot number 6 of the parent wireless terminal 101, and transmits data to the relay wireless terminal 201. To do. The relay wireless terminal 201 transmits the data received from the parent wireless terminal 101 in the slot 4 of the relay wireless terminal 201 to the relay wireless terminal 301 in the slot 5 by the same operation. The relay wireless terminal 301 receives data from the relay wireless terminal 201 in slot 3. The slave radio terminal 302 performs reception carrier sense every four slots to reduce power. The slot numbers in which the child radio terminal 302 is performing reception carrier sense are 1, 5, 9,. Therefore, the relay radio terminal 301 transmits the link connection signal and data in the lower slot of the slot number 7 of the relay radio terminal 301 corresponding to the slot number 5 of the child radio terminal 302 that the child radio terminal 302 is waiting for by reception carrier sense. The operation in which the relay wireless terminal 301 performs link connection with the child wireless terminal 302 is the same as the operation described in FIG.

  Next, a case where it is desired to send data from the child wireless terminal 302 to the parent wireless terminal 101 will be described. The child radio terminal 302 performs an operation of receiving the beacon signal from the relay radio terminal 301. Since the beacon signal from the relay wireless terminal 301 is transmitted every 2 slots = 4 seconds, the child wireless terminal 302 receives the beacon signal of the relay wireless terminal 301 within 4 seconds after the data transmission request is generated. can do. For example, when a data transmission request is generated at the slot number 252 of the child wireless terminal 302, the beacon signal of the beacon number 255 from the relay wireless terminal 301 is received at the slot number 253 of the child wireless terminal 302, and the received beacon number 255 Clock adjustment is performed with the beacon signal, the position of the link connection slot 25 shown in FIG. 3 is corrected, and the link connection signal is transmitted to the relay wireless terminal 301. The transmission / reception operation of the link connection signal from the child radio terminal 302 to the relay radio terminal 301 is the same as the operation described in FIG. The structure of the link connection signal is the same as the signal shown in FIG. 6A, but since there is almost no clock error, the number of repeated frame transmissions may be small. Through similar operations, data from the child wireless terminal 302 is transmitted to the parent wireless terminal 101.

  As described above, the wireless communication device, the wireless communication method, and the program according to the present invention vary the number of times the repeated frame is transmitted according to the time difference from the timing at which the communication partner receives the beacon signal in order to perform synchronization correction. Therefore, it is possible to set the optimum number of repeated frame transmissions and suppress an increase in power consumption.

DESCRIPTION OF SYMBOLS 1 Antenna 2 Transmission / reception means 3 Beacon transmission means 4 Beacon transmission control means 5 Link connection means 6 Repeat frame number setting means 7 Control means 11 Antenna 12 Transmission / reception means 13 Beacon reception means 14 Beacon reception control means 15 Carrier sense means 16 Link connection means 17 Control means 101 Parent wireless terminal 102-104, 202-204, 302-304 Child wireless terminal 201, 301, 401 Relay wireless terminal

Claims (7)

A communication partner periodically transmits a beacon signal for synchronizing transmission / reception timing, and when information to be transmitted is generated, a data signal is transmitted after a plurality of repeated frames including an identification code at the reception timing of the communication partner. In the wireless communication apparatus configured to transmit the present frame including the timing according to the time difference between the timing at which the information to be transmitted occurs and the timing at which the communication partner receives the beacon signal to perform synchronization correction A wireless communication apparatus configured to make the number of repeated frame transmissions variable. The wireless communication apparatus according to claim 1, wherein a timing at which transmission of the repeated frame is started is changed according to the number of transmissions. A beacon signal transmitted from the wireless communication device according to claim 1 is periodically received, reception timing correction is performed, and a reception operation is performed at an interval (1 / integer) of a reception interval for periodically receiving the beacon signal. A wireless communication apparatus that performs a reception operation at an interval of (1 / integer) according to a time difference between a timing of periodically receiving the beacon signal and a timing of performing a reception operation at the interval of (1 / integer) A wireless communication device configured to change a timing position. A step of periodically transmitting a beacon signal for the communication partner to synchronize transmission / reception timing; and a step of transmitting a repeated frame including an identification code a plurality of times at the reception timing of the communication partner when information to be transmitted is generated; In the wireless communication method including the step of transmitting the frame including the data signal after executing the step of transmitting a plurality of times, the timing at which the information to be transmitted is generated and the communication partner perform synchronization correction A wireless communication method for controlling the number of transmissions of the repetitive frame in the step of transmitting a plurality of times by the step of varying the number of times of transmission of the repetitive frame according to a time difference with a timing of receiving a beacon signal. The wireless communication method according to claim 4, wherein the transmission timing of the repetitive frame is changed according to the number of transmissions. A beacon signal transmitted from the wireless communication method according to claim 4 is periodically received, reception timing correction is performed, and a reception operation is performed at an interval (1 / integer) of a reception interval for periodically receiving the beacon signal. A wireless communication method, wherein a reception operation is performed at an interval of (1 / integer) according to a time difference between a timing of periodically receiving the beacon signal and a timing of performing a reception operation at the interval of (1 / integer) A wireless communication method configured to change a timing position. The program for making a computer implement | achieve at least one part of the wireless communication apparatus or wireless communication method of any one of Claims 1-6.

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