JP5691016B2 - Wireless communication system, wireless terminal, and program - Google Patents

Description

  The present invention relates to a wireless communication system that performs wireless communication between a parent wireless terminal and a child wireless terminal in a wireless system including one parent wireless terminal and a plurality of child wireless terminals.

  In a wireless system having a battery-driven child wireless terminal, it is generally used that the child wireless terminal waits for intermittent reception in order to reduce power consumption of the child wireless terminal. As a wireless communication system in which a child wireless terminal waits for intermittent reception, the parent wireless terminal periodically transmits a beacon signal, the child wireless terminal periodically receives the beacon signal, and the parent wireless terminal clock A radio communication system called a synchronization method that sets a clock and waits for reception of polling data from the parent radio terminal at a predetermined timing is effective for power saving of the child radio terminals.

  In such a synchronous wireless communication system, when a child wireless terminal transmits data to a parent wireless terminal, wireless transmission is performed using a predetermined frequency at a timing when the parent wireless terminal is waiting for reception. At the timing when the parent wireless terminal is waiting for reception, all the child wireless terminals do not need to wait for reception and are in a standby state.

  On the other hand, when data is transmitted from a parent wireless terminal to a specific child wireless terminal, the parent wireless terminal wirelessly transmits using a predetermined frequency at a timing when the specific child wireless terminal is waiting for reception. When the number of child wireless terminals increases, a situation occurs in which a plurality of child wireless terminals are waiting to receive data transmission from the parent wireless terminal at a timing when the specific child wireless terminal is waiting for reception. .

  When such a situation occurs, the child wireless terminal receives data transmission radio waves from the parent wireless terminal that are not destined for its own station, and continues to receive until it determines that it is not destined for itself. There has been a problem of increasing. In order to solve the above-described problem, it is conceivable to use a plurality of frequencies for communication between the parent wireless terminal and the child wireless terminal.

  An example in which a plurality of frequencies are used in a wireless communication system is disclosed in Patent Document 1. According to Patent Document 1, a downlink system band is divided by a fundamental frequency to form a plurality of downlink carrier elements, and an uplink system band is divided by a fundamental frequency to form a plurality of uplink carrier elements. It is shown that the parent radio terminal and the child radio terminal communicate with each other by making the downlink carrier element and the uplink carrier element correspond to each other.

  Further, in Patent Document 2, in a system that performs downlink communication using a plurality of carriers, the call signal of the mobile station group is associated with the carrier that transmits the call signal, and the own station belongs based on the identification number of the own station. It is shown that a mobile station group is calculated.

JP 2010-109488 A JP 2007-312134 A

  However, Patent Document 1 merely shows that the uplink frequency and the downlink frequency are associated with each other, and there is no detailed description on how to specifically correspond.

  In Patent Document 2, it is shown that a mobile station group to which the mobile station belongs is calculated based on the identification number of the mobile station and is associated with a downlink frequency, but the correspondence between the mobile station group and the downlink frequency is The radio access network apparatus performs transmission, and the radio access network apparatus needs to transmit mobile station group assigned carrier information to inform the mobile station of downlink frequency information. Note that the mobile station in Patent Document 2 corresponds to the child radio terminal in the present invention, and the radio access network device corresponds to the parent radio terminal in the present invention.

  As described above, in the conventional method, since it is necessary for the parent wireless terminal to determine the downlink frequency based on the identification number of the child wireless terminal and inform the child wireless terminal of the assigned carrier information, in order to inform the assigned carrier information There is a problem that a special frequency is required for use.

  Furthermore, there is a problem that a description of a specific method on how to associate an identification number with a downlink frequency is lacking.

  The present invention solves the above-described conventional problems, and can use a special frequency used for notifying the allocated carrier information with a simple configuration and method, and can efficiently correspond to the frequency in the downlink. An object is to provide a wireless communication system and a program.

  A wireless communication system including a parent wireless terminal and a plurality of child wireless terminals, wherein a frequency M used for downlink communication from the parent wireless terminal to the child wireless terminal uses a number M unique to the child wireless terminal. A wireless communication system and a wireless communication apparatus constituting the wireless communication system, characterized in that a remainder R obtained by dividing the number M by a predetermined number N is calculated to obtain a frequency corresponding to the R.

  Since the wireless communication apparatus has storage means for storing the frequency corresponding to the remainder R and reception means for waiting for reception at the frequency corresponding to the remainder R called from the storage means, A special frequency for notifying the frequency used in the downlink from the terminal is not required, and the frequency can be efficiently associated with the downlink.

  By using the wireless communication system, the wireless communication apparatus, and the program of the present invention, the frequency can be efficiently made to correspond to the downlink.

The block diagram of the radio | wireless communications system in 1st embodiment of this invention 1 is a configuration diagram of a wireless communication device used in a wireless communication system according to a first embodiment of the present invention. The figure which shows the frequency channel used for the radio | wireless communications system in 1st embodiment of this 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 The figure which shows the signal format of the signal for data communication in 1st embodiment of this invention The figure which shows the structure of the route information contained in the signal for data communication in 1st embodiment of this invention

  A first invention is a wireless communication system including a parent wireless terminal and a plurality of child wireless terminals, and a frequency used for downlink communication from the parent wireless terminal to the child wireless terminal is unique to each child wireless terminal. Using a predetermined number M, a remainder R obtained by dividing the number M by a predetermined number N is calculated, and a frequency corresponding to R is obtained.

  Then, a special frequency for notifying the frequency used in the downlink from the wireless terminal is not required by a simple configuration and method, and the frequency can be efficiently associated with the downlink.

  The second invention has a plurality of relay wireless terminals that wirelessly relay a signal from the parent wireless terminal, particularly in the first invention, the frequency used for downlink communication addressed to the plurality of relay wireless terminals, and the child wireless terminal The frequency used for the downstream communication is different.

  And since it has a storage means for storing the frequency corresponding to the remainder R, and a reception means for waiting for reception at the frequency corresponding to the remainder R called from the storage means, it can be transmitted from the parent wireless terminal on the downlink. It is possible to realize a child radio terminal that does not require a special frequency for informing the frequency to be used and can efficiently correspond to the downlink in the frequency.

  The third invention relates to a wireless terminal, a remainder calculating means for calculating a remainder R obtained by dividing a number M uniquely determined for a communication destination wireless terminal by a predetermined number N, and corresponding to the remainder R Storage means for storing the frequency to be transmitted, and transmission means for wireless transmission at a frequency corresponding to the remainder R called from the storage means.

  And since it has the memory | storage means to store the frequency corresponding to the said remainder R, and the receiving means which waits for reception with the frequency corresponding to the said remainder R called from the said memory | storage means, it is a downlink to a child radio | wireless terminal. It is possible to realize a parent radio terminal that does not require a special frequency for notifying the frequency to be used and can efficiently correspond to the downlink in the frequency.

  A fourth invention relates to a wireless terminal, and a remainder calculating means for calculating a remainder R obtained by dividing a number M uniquely determined for the own station by a predetermined number N, and a frequency corresponding to the remainder R And a receiving means for waiting for reception at a frequency corresponding to the remainder R called from the storing means.

  Since the downlink communication addressed to the relay wireless terminal and the downlink communication addressed to the child wireless terminal are configured to have different frequencies, the probability that the child wireless terminal erroneously detects that the radio wave not addressed to itself is a radio wave is present. The power consumption can be reduced, and an increase in power consumption can be prevented.

Since the fifth invention is a program for causing a computer to realize at least a part of a wireless communication system or a wireless communication device, at least one of the present invention is realized by cooperating hardware resources such as electrical / information equipment and a computer. Can be realized with 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 is a diagram illustrating an example of a wireless communication system according to the present invention. The outline of the operation of the wireless communication system of the present invention 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 child wireless terminals 202, 203, and 204 via the relay wireless 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.

  2 is an example of the wireless communication apparatus of the present invention, and is a wireless communication apparatus that can be used for a parent wireless terminal, a relay wireless terminal, and a child wireless terminal of the wireless communication system of FIG. Note that the configuration of the wireless communication apparatus illustrated in FIG. 2 may be applied to all of the parent wireless terminal, the relay wireless terminal, and the child wireless terminal. In addition, the parent wireless terminal may include a transmission unit but no reception unit. The child radio terminal may be configured to include a receiving unit but not a transmitting unit.

  In FIG. 2, 1 is an antenna, 2 is a receiving means, 3 is a frequency control means, 4 is a transmission means, 5 is a storage means, 6 is a remainder calculation means, and 7 is a control means. Transmission / reception of beacon signals is performed using a predetermined frequency channel dedicated for beacon transmission / reception. The frequency channel used for link connection and data communication, which will be described in detail later, is determined based on the table shown in FIG. A method for determining a frequency channel used for link connection and data communication will be described with reference to FIGS. 2 and 3A.

  The usable frequency channels are 16 frequency channels from ch1 to ch16. For example, ch1 is 429.0125 MHz and ch16 is 429.2 MHz, and channels are arranged at intervals of 12.5 kHz. Then, the frequency channels are grouped into two channels. For example, a channel group (hereinafter abbreviated as chg) 1 is composed of ch1 and ch9. FIG. 3A is a correspondence table between chg and frequency channel, and is stored in the storage means 5.

Each of the parent wireless terminal, the relay wireless terminal, and the child wireless terminal shown in FIG. 1 has a device identification code (hereinafter referred to as a device ID) for identifying each other device. For example, in FIG. 1, the device ID of the parent wireless terminal 101 is 101, the device ID of the child wireless terminal 102 is 102, and the relay wireless terminal 20
The device ID of 1 is 201. Hereinafter, it is assumed that the device ID of the wireless terminal *** is ***. When waiting for reception, the remainder calculating means 6 calculates the remainder obtained by dividing the device ID of the own station by the “number of chg”, and the control means 7 uses the storage means 5 for the frequency channel of chg corresponding to the calculated remainder. The receiving means 2 waits on that frequency channel.

  FIG. 3A is a comparison table of the “remainder”, “chg”, and “frequency channel”. In the example of FIG. 3A, since chg is 8 from 0 to 7, the remainder obtained by dividing the device ID by 8 is calculated. In the example of FIG. 1, the child wireless terminal 102 waiting to receive a link connection request on the downlink from the parent wireless terminal 101 has a remainder of 6 when the device ID 102 is divided by 8, so that the correspondence of FIG. According to the table, reception waiting is performed at chg6. Similarly, the relay wireless terminal 201 waits for reception at chg1, the child wireless terminal 103 at chg7, and the child wireless terminal 104 at chg0. On the other hand, when the parent wireless terminal 101 waits for reception of the uplink, similarly, the remainder 5 obtained by dividing the device ID 101 of the own station by “the number of chg = 8” is calculated, and the reception waiting is performed in chg5 corresponding to the remainder 5. Do. Therefore, when wireless transmission is performed to a partner station to be linked, a link connection request is made on one of the two channels of chg corresponding to the remainder obtained by dividing the device ID of the partner station by “number of chg = 8”. It will be.

  For example, in the method of assigning chg corresponding to the last digit of the device ID, when there are only 8 chg as shown in FIG. If the last digit of the device ID is 8 or 9, for example, it is assigned to chg0 and chg1, respectively, and the burden on chg0 and chg1 increases. On the other hand, as described above, the method of the present invention using the chg corresponding to the remainder obtained by dividing the device ID of the counterpart station by “the number of chg = 8” allows the frequency channel without burdening the specific frequency channel. There is a great merit that can be used evenly.

  The operation of the wireless communication system of the present invention will be described in more detail. The wireless communication system of the present invention shown in FIG. 1 is configured to perform communication by dividing the time axis into a plurality of slots. FIG. 4A shows a basic slot configuration used in the wireless communication system 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, a slot 31, a slot 32, and a slot 33. The slot 31 is a beacon transmission slot (BT), the slot 32 is a link connection slot (L), and the slot 33 is a data communication slot (D). Similarly, the upper slot is further divided into three slots 34, 35, and 36. The slot 34 is a beacon receiving slot (BR), the slot 35 is a link connection slot (L), and the slot 36 is a data communication slot (D).

  The host device periodically transmits a beacon signal using the beacon transmission slot (BT) of the slot 31. 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 upper device in the beacon receiving slot (BR) of the slot 34. 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 32 and the slot 35 is a slot in which the upper device and the lower device communicate for link connection. The slot for data communication (D) of the slot 33 and the slot 36 is a slot for performing communication for exchanging data after the link connection between the upper device and the lower device.

  The link connection slot (L) of the slots 32 and 35 is composed of two slots, a slot 37 and a slot 38, as shown in FIG. 4B. Slot 37 is a lower call slot, and slot 38 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 37, and T3 is the slot length of the higher response / upper call slot 38.

  FIG. 5 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 43 in the slot of FIG. 5, the notation “lower” indicates the lower slot of FIG. Similarly, as shown in the slot 44, the notation “upper” indicates the upper slot in FIG. A basic slot 42 is a basic slot composed of a lower slot 43 and an upper slot 44. 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. 5, reference numeral 41 denotes a beacon signal. In FIG. 5, 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 41 transmitted from the slot number 1 of the parent wireless terminal 101. The beacon signal 41 carries the beacon number 1 corresponding to the slot number 1. When the relay wireless terminal 201 receives the beacon signal 41 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. 5, 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.

More specifically, the relay wireless terminal 201 receives the beacon signal 41 with the beacon number 1 transmitted from the parent wireless terminal 101 at the slot number 255 of the relay wireless terminal 201, and the beacon number 1 from the slot number 1 of the relay wireless terminal 201. The beacon signal 46 is transmitted. The beacon signal 45 transmitted from the slot number 3 of the parent wireless terminal 101 is transmitted at the timing of the upper slot of the slot number 1 of the relay wireless terminal 201. That is, the relay wireless terminal 201 transmits a beacon signal in the beacon transmission slot 31 (see FIG. 4) in the lower slot of the slot number 1 of the relay wireless terminal 201 immediately before the parent wireless terminal 101 transmits the beacon signal 45. . Similarly, the relay wireless terminal 301 transmits a beacon signal in the beacon transmission slot 31 in the lower slot of the slot number 255 of the relay wireless terminal 301 immediately before the beacon signal 46 transmitted by the relay wireless terminal 201. As described above, the lower relay radio terminal transmits the beacon signal at the slot position immediately before the beacon signal transmitted by the upper relay radio terminal or the parent radio terminal.

  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 upper call slot 38 (see FIG. 4) among all the upper 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. Accordingly, 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 38 in the lower slot of the slot number 6.

  The relay radio terminal 201 performs reception carrier sense in the higher call slot 38 in the higher slot of the slot number 4, and receives the link connection signal from the parent radio terminal 101 after carrier sense.

  The message format of the link connection signal is shown in FIG. The link connection signal is composed of n repeating frames 51 to 56 and a main body frame 57. FIG. 6B shows the configuration of the repetitive frame. The repetitive frame identifies a bit synchronization signal 58 for determining a bit sampling position, a frame synchronization signal 59 for detecting the head of data included in the frame, a control signal 60 carrying various control information and a device. The identification code (hereinafter referred to as ID) is simplified ID 61. The ID is, for example, 64 bits, and the simple ID is 16 bits obtained by dividing the ID into four. Information indicating which 16 bits of the ID divided into four are used as the simple ID 61 is in the control signal 60. The repetitive frame length is T6. Therefore, n repetitive frame lengths T7 are T7 = n × T6. Repetitive frames 51 to 56 are given repetitive frame numbers 1 to n, and the repetitive frame number is added to the control signal 60. The repeated frame is transmitted from a repeated frame having a large repetition number as shown in FIG. 6A. The repeated frame number is decremented one by one, and the repeated frame number immediately before the main body frame is 1.

  FIG. 7 is a diagram for explaining the reception carrier sense timing. FIG. 7A 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. (B-1) in FIG. 6B is a case where the clocks of the upper device and the lower device are not shifted, and (b-2) is a case where the clock of the lower device is advanced with respect to the clock of the upper device. 3) shows a case where the clock of the lower device is delayed with respect to the clock of the upper device. Reference numeral 70 denotes the head position of the higher-order call slot of the lower-order device. Reference numeral 71 denotes a reception carrier sense timing of the lower device. The reception carrier sense timing is set to T8 = T7 / 2 from the head position 70 of the upper call slot. With this setting, if the clock deviation ΔT between the upper device and the lower device is in a 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 clock 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. 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. 5, when a data transmission request addressed to the child wireless terminal 302 occurs at the parent wireless terminal 101 at the time of slot number 5, for example, the link connection signal is transmitted at the higher call slot 38 in the lower slot of slot number 6. Send. The relay radio terminal 201 performs reception carrier sense in the upper call slot 38 in the upper slot of slot number 4, and receives the link connection signal from the parent radio terminal 101 after carrier sense. Since relay wireless terminal 201, which is a lower-level device, performs clock adjustment at the timing of beacon signal 41, 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 frames transmitted in the link connection signal is made variable according to the time from the time when the clock is set with the beacon signal 41 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 41 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 made variable, the time T7 in FIG. 7 is also made variable. Therefore, if T8 which is the reception carrier sense timing is fixed, the carrier sense timing 71 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 adjusted in association with T7 so that the carrier sense timing 71 comes to the center of T7, and T8 is made variable in association with T7. 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 transmission start position of the link connection signal shown in FIG. 7A can be made variable. The link connection signal from the higher-level device is transmitted in the higher-order call slot 38 in the slot 32 of FIG. 4A, 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 number in which the child wireless terminal 302 is performing the reception carrier sense is on the route information included in the signal addressed to the child wireless terminal 302 transmitted from the parent wireless terminal 101 and relay-transmitted by the relay wireless terminal 201 and the relay wireless terminal 301. You can know from the information you have. Details of the route information will be described later. Here, as a result of analyzing the route information, it is assumed that 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. When transmission from the lower device to the upper device occurs, the lower device receives the beacon signal transmitted by the upper device, and the link connection slot immediately after the beacon reception slot 34 (see FIG. 4) from which the beacon signal is received. The link connection signal shown in FIG. This will be specifically described below.

  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 47 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 is received. The beacon signal 47 of the slave wireless terminal 302 is adjusted to adjust the position of the link connection slot 35 shown in FIG. 4 in the upper slot 48 of the slot number 253 of the child wireless terminal 302, and the link connection signal is transmitted to the relay wireless terminal 301. Then, link connection operation is performed. The relay wireless terminal 301 performs a link connection operation with the child wireless terminal 302 in the lower slot of the slot number 255 of the relay wireless terminal 301. The transmission / reception operation of the link connection signal from the child wireless terminal 302 to the relay wireless terminal 301 is the same as the operation described in FIG. The configuration of the link connection signal is the same as the signal shown in FIG. 7A, but there is almost no clock error, so the number of repeated frame transmissions may be small. Then, after the link connection is completed, the child wireless terminal 302 transmits a signal addressed to the parent wireless terminal 101 in the data communication slot 36 in the same upper slot where the link connection is made. The relay wireless terminal 301 receives the signal addressed to the parent wireless terminal 101 in the data communication slot 33 in the lower slot corresponding to the child wireless terminal 302.

  Next, the relay wireless terminal 301 receives the beacon signal 46 transmitted from the relay wireless terminal 201 using the slot number 255 of the relay wireless terminal 301, performs time adjustment using the received beacon signal 46, and sets the slot number 255 of the relay wireless terminal 301. The position of the link connection slot 35 shown in FIG. 4 in the upper slot is corrected, and a link connection signal is transmitted to the relay wireless terminal 201 to perform a link connection operation. The relay wireless terminal 201 performs a link connection operation with the relay wireless terminal 301 in the lower slot of slot number 1 of the relay wireless terminal 201. Then, after the link connection is completed, the relay wireless terminal 301 transmits a signal addressed to the parent wireless terminal 101 in the data communication slot 36 in the same upper slot where the link connection is made. The relay wireless terminal 201 receives the signal addressed to the parent wireless terminal 101 in the data communication slot 33 in the lower slot corresponding to the relay wireless terminal 301.

  Similarly, the relay wireless terminal 201 receives the beacon signal 45 transmitted by the parent wireless terminal 101 at the slot number 1 of the relay wireless terminal 201, performs time adjustment with the received beacon signal 45, and sets the slot number 1 of the relay wireless terminal 201. The position of the link connection slot 35 shown in FIG. 4 in the upper slot is corrected and a link connection signal is transmitted to the parent wireless terminal 101 to perform a link connection operation. The parent wireless terminal 101 performs a link connection operation with the relay wireless terminal 201 in the lower slot of slot number 3 of the parent wireless terminal 101. Then, after the link connection is completed, the relay wireless terminal 201 transmits a signal addressed to the parent wireless terminal 101 in the data communication slot 36 in the same upper slot that has been linked. The parent wireless terminal 101 receives a signal addressed to the parent wireless terminal 101 in the data communication slot 33 in the lower slot corresponding to the relay wireless terminal 201.

As described above, the beacon signal of the higher-level device is transmitted in the slot immediately after the transmission of the beacon signal of the lower-level device. In transmission, relay transmission can be performed efficiently without significant delay.

  Now, in the wireless communication system shown in FIG. 1 described above, the operation of turning on the power of the child wireless terminal 302 and entering the wireless communication system of FIG. 1 will be described. The child radio communication terminal 302 performs a reception operation for a predetermined time and receives a beacon signal. When a plurality of beacon signals are received within the predetermined time, the beacon signal of the local station is transmitted to which beacon signal by using the reception level of the received beacon signal and the relay stage number information of the relay wireless terminal transmitting the received beacon signal. Decide whether to match. In the example of FIG. 1, the child radio terminal 302 receives the beacon signal of the relay radio terminal 301 and performs time adjustment, and in the lower call slot 37 in the link connection slot 35 (see FIG. 4) following the beacon signal. The link connection signal shown in FIG. 6A is transmitted to the relay wireless terminal 301. The number of repeating frames is 5. Then, a response signal permitting link connection from the relay wireless terminal 301 is received in the upper response slot 38. The link connection has been established between the relay wireless terminal 301 and the child wireless terminal 302 by the operations so far. Next, the child wireless terminal 302 transmits the entry request signal addressed to the parent wireless terminal 101 as the final destination to the relay wireless terminal 301 having a link connection established in the data communication slot 36 shown in FIG. Request a relay. FIG. 8 shows a format of a signal transmitted / received in the data communication slot 36. That is, the child radio terminal 302 transmits the data communication signal shown in FIG. Here, the link partner ID 83 of the signal transmitted to the relay wireless terminal 301 is the ID of the relay wireless terminal 301, and the own station ID is the ID of the child wireless terminal 302. The control signal 82 contains information on the signal length from the link partner ID 83 to the end of the layer 3 frame. Therefore, by receiving and analyzing the control information 82, it is possible to know how far the signal should be received.

  The structure of the layer 3 frame 85 is shown in FIG. The layer 3 frame 85 is a frame signal relayed to the final destination. That is, the layer 3 frame 85 transmitted from the child radio terminal 302 shown in FIG. 1 is sent to the parent radio terminal 101 via the relay radio terminal 301 and the relay radio terminal 201 via the relay. The authentication code 86 is a code for checking whether or not the layer 3 frame 85 is a regular frame. In the route information 87, route information from the child wireless terminal 302 to the parent wireless terminal 101 is created by the relay wireless terminals 301 and 201 and sent to the parent wireless terminal 101. The layer 3 ID 88 contains the ID of the child wireless terminal 302 that is the first transmission source. Application data 89 is data related to an application to be transmitted to the parent wireless terminal 101.

  FIG. 9 shows the configuration of the route information 87. The route information 87 is composed of 8 bytes, and information on relay wireless terminals on the relay route from the child wireless terminal 302 to the parent wireless terminal 101 is entered from the first byte to the seventh byte. The child radio terminal 302 transmits the data communication signal shown in FIG. 7 to the relay radio terminal 301 to which the own station belongs. At this time, the slot position information 91 in which the child radio terminal 302 waits to receive a signal from the relay radio terminal 301, that is, is receiving carrier sense, enters the slot position which is the eighth byte of the route information 87. The slot position information 91 is composed of 8 bits.

The meaning of each bit of the slot position information 91 will be described. 2 bits D5 to D4 indicate the intermittent reception period m of the relay radio terminal and the child radio terminal in the radio communication system shown in FIG. 2, but in the case of the normal relay radio terminal, m = 1, that is, all slots I'm waiting to receive. When m = 2, it indicates that reception is waited every two slots. Four bits D3 to D0 indicate center polling, that is, a slot position number x for waiting to receive a signal from a relay wireless terminal that is a higher-level device. The slot position number x indicates the (x−1) th slot counted from the reference slot number defined below.
Here, x = 1 to the range of the intermittent reception cycle m. The definition of the reference slot number is as follows.

Reference slot number = a × m + 1
Here, a is an integer from 0 to 0 (number of slots 255 / intermittent reception cycle m).

  That is, the reference slot exists for every m slots, slot number 1, m + 1, 2 × m + 1,... Shown in FIG. Therefore, the slot number y waiting for reception is “slot number y waiting for reception = reference slot number + slot position number x−1”. Then, the slave wireless terminal 302 transmits two pieces of information of the intermittent reception cycle m of the slave wireless terminal and the slot position number x to the parent wireless terminal 101 using the slot position information 91, and the parent wireless terminal 101 stores the route information table of the child wireless terminal 302 Create The intermittent reception period m is preferably a common value in the wireless communication system, but may be different for each child wireless terminal. Each slave wireless terminal arbitrarily sets the slot position number x. The route information 87 created by the child radio terminal 302 is only the slot position information 91, and “0x00” is inserted into the relay radio terminal information from the first byte to the seventh byte. If the transmission source is a relay wireless terminal, “0xFF” is inserted. The creation and transmission of the slot position information 97, which is the intermittent reception standby timing in such a child radio terminal, is performed by the control means 7 in FIG.

  The advantage that the child wireless terminal 302 determines the slot position when entering is that, after transmitting the entry request signal to the parent wireless terminal 101, the intermittent reception waiting slot for receiving the entry permission signal from the parent wireless terminal 101 is determined by itself. Therefore, the slave wireless terminal 302 can wait in a standby state until the intermittent reception waiting slot.

  An overview of route information management will be described. The child radio terminal manages only the slot position information of the relay radio terminal to which it belongs. The relay radio terminal manages the relay radio terminal directly under its own station as a table, and manages so that the correspondence between the table number and the relay radio terminal directly under the local station can be obtained. The parent wireless terminal manages the slot position information of the child wireless terminal and the table number information of the relay wireless terminal existing in the route to the child wireless terminal. The relay wireless terminal information will be described in detail below.

  The byte structure of the relay wireless terminal information is shown at 90 in FIG. The bit configuration of the relay wireless terminal information 90 will be described below. D7 has a different meaning in the case of communication from the upper device to the lower device and in the case of communication from the lower device to the upper device. In the case of communication from a higher-level device to a lower-level device, it indicates the presence / absence of a table number deletion request, and the deletion request is made by the parent wireless terminal. In the case of communication from a lower device to a higher device, this is an identifier for identifying whether the table held by each relay wireless terminal is full. The meaning of D6 also differs in the case of communication from the upper device to the lower device and in the case of communication from the lower device to the upper device. Whether or not the relay wireless terminal is a relay wireless terminal registered in the table for the first time this time, if the communication from the upper device to the lower device is fixed to "0", and if the communication from the lower device to the upper device is not in the table Identifier. Six bits D5 to D0 indicate the table number of the relay radio terminal immediately below that is managed by the relay radio terminal in the relay route. Up to 63 table numbers can be managed. Except for the table number “0”, 63 relay wireless terminals with the table numbers “1” to “63” can be managed.

The relay wireless terminal 301 that has received the route information 87 from the child wireless terminal 302 analyzes a byte corresponding to the number of steps of the received station in the route information 87. Since relay wireless terminal 301 is in the second stage, the second byte is analyzed. If the analysis result is “0x00”, the transmission source is relay from any of child wireless terminals 202, 203, and 204 belonging to relay wireless terminal 301. Interpret as a request. If the analysis result is “0xFF”, it is interpreted that the transmission source is the relay wireless terminal 401. If it is a relay request from the slave radio terminals 202, 203, and 204, the table number “0” is set to the byte of the stage number to which the own station belongs, that is, D5 to D0 of the second byte. In the example of FIG. 1, since it is a relay request from the child radio terminal 302, the table number “0” is set in D5 to D0 of the second byte.

  If the analysis result is “0xFF”, it is determined that the relay request is from the relay wireless terminal, and the table number corresponding to the relay wireless terminal is set in D5 to D0 of the number of bytes to which the own station belongs. When the relay request is from the relay wireless terminal but the relay terminal information is not in the table managed by the local station, the relay wireless terminal is registered in the table, and the registered table number belongs to the local station. Set to D5 to D0 of the byte at the stage number.

  The route information 87 described above is transmitted from the relay wireless terminal 301 to the relay wireless terminal 201. The relay wireless terminal 201 also performs the same analysis and creation processing of the route information 87 as the relay wireless terminal 301, and corresponds to the relay wireless terminal 301 in the first byte D5 to D0 corresponding to the first stage to which the relay wireless terminal 201 belongs. A table number is set and the created route information 87 is transmitted to the parent wireless terminal 101.

  In the relay radio terminal 201 and the relay radio terminal 301, analysis and creation of the route information 87 including the slot position information 91 which is the slave radio terminal intermittent reception standby timing is performed by the control means 7 in FIG.

  The parent wireless terminal 101 can know the relay route to the child wireless terminal 302 by analyzing the route information 87. That is, the first byte of the route information 87 has a table number corresponding to the ID of the relay wireless terminal 301 managed by the relay wireless terminal 201, and the table information of the second byte of the route information 87 is the table number “0”. This indicates that the transmission source is a child radio terminal. In the eighth byte of the route information 87, there is information on the intermittent reception cycle m and the slot position number x of the child wireless terminal that is the transmission source. The ID of the child radio terminal 302 that is the transmission source can be known from the layer 3 ID 88 in FIG. The analysis and creation of the relay terminal information 90 in the parent wireless terminal 101 is performed by the control means 7 in FIG. 2, and the creation and transmission of the slot position information 97 that is the intermittent reception waiting timing in the child wireless terminal is performed by the control means 7 in FIG. Done. Information relating to route information 87 including slot position information 97 and relay terminal information 90 is stored in the control means 7.

  As described above, the parent wireless terminal 101 obtains route information to all the child wireless terminals belonging to the wireless communication system shown in FIG. 1 from the route information 87 included in the signal transmitted to the parent wireless terminal 101 when the child wireless terminal enters. You can know and create a route information table.

Next, a case where polling data is sent from the parent wireless terminal 101 to the child wireless terminal 302 will be described. The parent wireless terminal 101 creates route information 87 including the relay route to the child wireless terminal 302, the intermittent reception period m of the child wireless terminal 302, and the slot position number x with reference to the route information table of the own station. Then, the link connection signal shown in FIG. 6 is transmitted to the relay wireless terminal 201 in the upper call slot 37 in the link connection slot of the lower slot. Since the relay radio terminal 201 is waiting for intermittent reception in all higher call slots, it can receive a link connection signal addressed to itself from the parent radio terminal 101. The relay wireless terminal 201 receives the data communication signal shown in FIG. 8 transmitted from the parent wireless terminal 101 in the data communication slot 36, confirms the layer 3 ID 88 included in the layer 3 frame 85, and must be addressed to itself. For example, the first byte of the route information 87 (see byte configuration 90 in FIG. 9) is analyzed as a relay request. If the table number written in the D5 to D0 bits of the first byte is “0”, this indicates that it is addressed to the child wireless terminal that belongs directly to the own station. Therefore, the table number written in the D5 to D0 bits of the first byte is a table number in which the ID of the relay wireless terminal 301 is described. Accordingly, the relay wireless terminal 201 can know the ID of the relay wireless terminal 301 as the next relay destination by referring to the table held by the own station from the table number written in the D5 to D0 bits of the first byte. The relay wireless terminal 201 performs link connection with the relay wireless terminal 301 in the same procedure as the parent wireless terminal 101, and relays and transmits a data communication signal to the relay wireless terminal 301. The relay wireless terminal 301 performs an analysis operation similar to that of the relay wireless terminal 201 described above, and confirms the table number written in the D5 to D0 bits of the second byte of the route information 87. Since the table number written in the D5 to D0 bits of the second byte is “0”, it is recognized that it is addressed to the child radio terminal directly under the own station. Then, the ID of the child radio terminal directly under the own station can be known by the layer 3 ID 88 included in the received data communication signal. In the layer 3 ID 88, the ID of the child wireless terminal 302 that is the final destination is written. Then, the slot position information 91 of the eighth byte of the route information 87 is analyzed, and the intermittent reception cycle m and the slot position number x of the child radio terminal 302 can be known. As described above, the slot in which the slave radio terminal 302 is waiting for intermittent reception is calculated from the intermittent reception cycle m and the slot position number x, and the relay radio terminal 301 performs link connection with the slave radio terminal 302 in that slot, and the data Relay transmission of communication signals. The layer 3 frame 85 is created by the parent wireless terminal 101 and is relayed and transmitted to the child wireless terminal 302 without being changed by the relay wireless terminals 201 and 301. The child wireless terminal 302 receives the application data 89 from the parent wireless terminal 101. be able to.

  As described above, the reception waiting slot information of the child wireless terminal is sent on the signal from the parent wireless terminal during communication. Therefore, the relay wireless terminal has a table for managing only the relay wireless terminal directly under the local station. It is not necessary to have any information on the child radio terminal directly under the own station. Therefore, there is no need to set a limit on the number of child radio terminals that belong directly under the own station. In other words, it is possible to reduce the table held by the own station.

  Further, the parent wireless terminal 101 can also reduce the table for storing route information to the child wireless terminal. For example, the parent wireless terminal 101 needs to manage the ID of the relay wireless terminal 201 immediately below, but instead of directly managing the ID of the relay wireless terminal 301 that is not directly below, the relay wireless terminal 301 managed by the relay wireless terminal 201 is managed. What is necessary is just to manage a table number. If the maximum number of relay wireless terminals managed by each relay wireless terminal is 63, the required number of tables is 63, and 6-bit information is sufficient for the table number. Therefore, 64-bit management is sufficient for 6-bit management per relay wireless terminal.

  Further, since the route information carried on the data communication signal is not the ID of the relay wireless terminal of the relay route but the table number corresponding to the ID, the number of bytes of the route information can be reduced. For example, if the maximum number of relay wireless terminals managed by each relay wireless terminal is 63, a relay route per stage can be set with 6-bit information. In general, an ID for designating a wireless terminal requires a large number of bits such as 64 bits. Therefore, in the method of sending the relay wireless terminal ID of the relay route as route information, the route information becomes very large and communication is wasted. On the other hand, according to the method of transmitting the table number shown in this embodiment as route information, the route information can be reduced and efficient communication can be performed.

  In this embodiment, the parent wireless terminal 101 stores and manages the slot position information of the child wireless terminal 302, but the relay wireless terminal 301 can also manage it. In this case, the table of the relay wireless terminal 301 becomes large, but there is an advantage that the slot position information at the 8th byte of the route information 87 is unnecessary.

  In the description of the present embodiment, the description has been made on the assumption that there are three types of terminals: a parent wireless terminal, a relay wireless terminal, and a child wireless terminal. However, in terms of the relationship between the child wireless terminal and the relay wireless terminal, the relay wireless terminal is the parent wireless terminal. It is a wireless terminal.

  As described above, since the uplink and downlink time slots are different in this embodiment, the relay radio terminal and the child radio terminal linked with the parent radio terminal 101 erroneously send a signal addressed to the parent radio terminal 101. There is no detection. However, for example, a signal addressed by the parent wireless terminal 101 to the child wireless terminal 303 waits for reception in the same time slot by all relay wireless terminals and child wireless terminals linked to the parent wireless terminal 101 in the link connection slot 35 of FIG. ing. Therefore, if all relay wireless terminals and child wireless terminals linked to the parent wireless terminal 101 are waiting for reception using the same chg, the parent wireless terminal 101 sends a signal addressed to the child wireless terminal 303 to the parent wireless terminal 101. All relay wireless terminals and child wireless terminals linked to the terminal perform signal detection, and reception is continued until it is determined that it is not addressed to the own station, resulting in wasteful power consumption. Since the present invention is configured to allocate different chg to each terminal that performs link connection reception, the probability of detecting a link connection signal addressed to another station transmitted by the parent wireless terminal 101 is reduced, and power due to wasted reception is reduced. Consumption can be suppressed.

  Furthermore, when there are more child wireless terminals connected via the relay wireless terminal 201 than there are child wireless terminals directly connected to the parent wireless terminal 101, downlink communication addressed to the relay wireless terminal 201 increases. Then, the child wireless terminal (chid wireless terminal with device ID 105 not shown in FIG. 1) using chg1 which is the same chg as the relay wireless terminal 201 transmits downlink communication from the parent wireless terminal 101 addressed to the relay wireless terminal 201. It is conceivable that the power consumption of the child radio terminal using chg1 for downlink communication will increase extremely compared to other child radio terminals. Therefore, a method of separating the chg used by the relay wireless terminal for reception and the chg used by the child wireless terminal for reception can be considered.

  FIG. 3B shows an example in which chg of link communication used for reception of the relay radio terminal and the slave radio terminal is separated. (1) in FIG. 3B is an example of chg used by the relay wireless terminal for reception. Five of the eight chgs are assigned to the relay radio terminal. Accordingly, the device ID of the relay wireless terminal is obtained as “remainder divided by 5”, and the remainders 0 to 4 correspond to chg0 to chg4, respectively. On the other hand, an allocation table of chg used for reception of the child radio terminal is shown in (2) of FIG. Of the 8 chgs, 3 which are not allocated to relay radio terminals are allocated to the child radio terminals. Accordingly, the device ID of the child wireless terminal is obtained as “remainder divided by 3”, and the remainders 0 to 2 are associated with chg5 to chg7, respectively. The number of chg allocated to the relay radio terminal and the number of chg allocated to the child radio terminal may be allocated optimally for each system depending on the number of child radio terminals hanging under the relay radio terminal.

The comparison table between chg and the remainder shown in FIG. 3 has been described as an example used for link connection. The chg used for transmission / reception in the data communication slot (D) after link connection (33 or 36 in FIG. 4) may be different from the chg used for link connection. The same chg is used for chg and chg used for data communication. Furthermore, the subsequent link connection response and data communication are performed at the frequency ch for which the link connection request is made. For example, consider a case where a link connection request is made from the parent wireless terminal 101 to the child wireless terminal 102. The parent wireless terminal 101 transmits a link connection request using ch7 or ch15 of chg6. For example, when transmission is performed on ch7, subsequent data communication is also performed on ch7. Then, the slave wireless terminal 102 receives the link connection request by performing carrier detection for detecting the presence or absence of radio waves at ch7 and ch15 as described above, and starts reception at the ch where the carrier is detected. The child wireless terminal 102 that has received the link connection request from the parent wireless terminal 101 omits the operation of detecting the presence / absence of a carrier in ch7 that has received the link connection signal in the data communication slot (D) (36 in FIG. 4). Receive standby. The reason why subsequent communication is performed using the same frequency ch as the link connection request signal is that the third party is less likely to use the frequency ch used for link connection in the subsequent communication and detects the presence or absence of a carrier. This is because the operation can be omitted and the standby reception can be performed, so there is no need to load an unnecessary header, so that the message length can be shortened and the power consumption can be suppressed.

  In the present embodiment, the number M unique to the wireless terminal in the claims is the device ID, and the predetermined number N is the number of received chg allocated to the relay wireless terminal or the child wireless terminal. The unique number M is not limited to the device ID, and may be a number corresponding to the manufacturing number. The predetermined number N is 8 in this embodiment, but may be a value exceeding 10 or 16 such as 19, for example.

  As described above, the wireless communication system, the wireless communication apparatus, and the program according to the present invention do not require a special frequency for notifying the frequency used in the downlink from the wireless terminal, and efficiently convert the frequency to the downlink. It is possible to provide a wireless communication system that can be adapted.

DESCRIPTION OF SYMBOLS 1 Antenna 2 Receiving means 3 Frequency control means 4 Transmission means 5 Storage means 6 Remainder calculation means 7 Control means 101 Parent wireless terminal 201, 301, 401 Relay wireless terminal 102-104, 202-204, 302-304 Child wireless terminal

Claims (3)

It is composed of a parent wireless terminal and a plurality of child wireless terminals or relay wireless terminals, and the parent wireless terminal periodically transmits a beacon signal, and the child wireless terminal or the relay wireless terminal receives the beacon signal and transmits the beacon signal. A reception operation is performed at a predetermined interval in time synchronization with the radio terminal, and downlink communication addressed to the child radio terminal or the relay radio terminal from the parent radio terminal is performed at the timing at which the reception operation is performed at the predetermined interval. A wireless communication system that transmits from a wireless terminal at a communication frequency , wherein the communication frequency is a frequency different from the beacon frequency and is uniquely determined for each of the child wireless terminals or the relay wireless terminals using numbers M, the number M to calculate a remainder R obtained by dividing a predetermined number N, the radio communication system which is characterized by using a frequency in correspondence to the R . The frequency for uplink communication from the child radio terminal or the relay radio terminal to the parent radio terminal uses a number M uniquely determined for the parent radio terminal, and a remainder R obtained by dividing the number M by a predetermined number N The wireless communication system according to claim 1, wherein a frequency calculated and made to correspond to R is used . The program for making a computer implement | achieve at least one part of the radio | wireless communications system of Claim 1 or 2 .