JP2019036846A - Radio communication device, radio communication system, and radio communication method - Google Patents

Abstract

To reduce the amount of communication data to be transmitted and received in the entire network so that the data can be correctly transmitted, in transmitting and receiving a data frame to and from radio communication devices by flooding without replacing channel information.SOLUTION: A radio communication device according to the present invention is a radio communication device that performs radio communication of communication signals by broadcasting, and comprises: transmission and reception means that transmits and receives communication signals; standby time measuring means that measures a predetermined standby time for a transmission time required for transmission of a communication signal received by the transmission and reception means; and communication control means that controls transfer of the communication signal or transmission of a response signal according to a transmission destination of the communication signal received by the transmission and reception means, and performs transfer processing for the received communication signal on the basis of the standby time measured by the standby time measuring means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless communication device, a wireless communication system, and a wireless communication method.

  In wireless communication multi-hop networks in which multiple wireless communication devices deliver data frames to the intended destination by transferring data frames, route information is exchanged between adjacent wireless communication devices to determine the forwarding destination for the data frame destination As a routing protocol (route construction protocol) for constructing a routing table to perform, there is RPL.

  The RPL updates the shortest path information to the border router based on the distance information to the border router held in a DIO (DAG Information Object) message periodically exchanged with a neighboring node, thereby allowing communication nodes to communicate with each other. This is a protocol devised to cope with changes in the link state of (see Non-Patent Document 1).

RFC 6550: International Organization for Standardization IETF Standardization Technology RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks

  However, if the change in the network topology due to the movement of the wireless communication device is faster than the restoration rate (update rate) of the route information by the periodically exchanged DIO message, the route information in the route update process becomes old and correct routing is performed. There may be cases where it cannot be done.

  In response to the above problem, there is also a method of constructing a routing table by operating a path construction protocol every time data is transferred, such as AODV (Ad hoc On-Demand Distance Vector). However, in this method, the request node transmits data (message) by broadcast, the other node transfers the received data, and transmits the data to all the nodes in the network, and the flooding until the message reaches the request node. Since communication is performed along the reverse path, the communication cost becomes very high.

  Further, as a conventional technique, it is conceivable to use a method called flooding for transferring data to all wireless communication apparatuses in a relayable multi-hop network without requiring a route construction protocol.

  However, conventional data transfer by general flooding requires that all wireless communication devices that are not data frame destinations perform data transfer by broadcast, which increases the amount of communication data transmitted and received over the entire network. The communication load becomes very high.

  Therefore, the present invention suppresses the amount of communication data transmitted / received in the entire network and correctly transfers data when transmitting / receiving data frames to / from each wireless communication device constituting the network by flooding without exchanging route information. It is an object of the present invention to provide a wireless communication device, a wireless communication system, and a wireless communication method that can be used.

  In order to solve such a problem, a wireless communication device according to a first aspect of the present invention includes: (1) a transmission / reception unit for transmitting / receiving a communication signal; and (2) a transmission / reception unit in a wireless communication device for wirelessly communicating a communication signal by broadcast. A waiting time measuring means for measuring a predetermined waiting time for the transmission time relating to the transfer of the communication signal received by (3), and (3) depending on the destination of the communication signal received by the transmitting / receiving means, The control unit controls transmission of the response signal, and includes a communication control unit that performs a transfer process of the received communication signal based on the standby time measured by the standby time measuring unit.

  A wireless communication system according to a second aspect of the present invention is a wireless communication system in which communication signals are wirelessly communicated by broadcast among a plurality of wireless communication devices. (1) Transmission / reception means for each wireless communication device to transmit and receive communication signals And (2) a waiting time measuring means for measuring a predetermined waiting time for the transmission time related to the transfer of the communication signal received by the transmitting / receiving means, and (3) depending on the destination of the communication signal received by the transmitting / receiving means. And a communication control means for controlling the transfer of the communication signal or the transmission of the response signal, and performing the transfer process of the received communication signal based on the standby time measured by the standby time measuring means. It is characterized by.

  A wireless communication method according to a third aspect of the present invention is a wireless communication method in which communication signals are wirelessly communicated by broadcasting among a plurality of wireless communication devices. Each wireless communication device is received by a transmission / reception unit that transmits and receives communication signals. A predetermined waiting time is measured for the transmission time related to the transfer of the communication signal, and the transfer of the communication signal or the transmission of the response signal is controlled according to the transmission destination of the communication signal received by the transmission / reception means. The received communication signal is transferred based on the waiting time measured by the waiting time measuring means.

  According to the present invention, when a data frame is transmitted / received to / from each wireless communication device constituting the network by flooding without exchanging route information, the amount of communication data transmitted / received in the entire network is suppressed and data transfer is performed correctly. can do.

It is an internal block diagram which shows the internal structure of the radio | wireless communication apparatus which concerns on embodiment. It is a flowchart which shows the operation | movement of the reception process of the data frame which concerns on embodiment. It is a flowchart which shows the operation | movement of the reception process of the response frame which concerns on embodiment. It is explanatory drawing which shows the change of the network topology by the movement of the radio | wireless communication apparatus which concerns on embodiment. It is an internal structure of the radio | wireless communication apparatus corresponding to the conventional flooding system. It is a flowchart which shows the flooding process sequence in the conventional radio | wireless communication apparatus. It is a figure which shows arrangement | positioning of radio | wireless communication apparatus AG and R, and the communication range of a radio | wireless communication apparatus.

(A) Main Embodiment Hereinafter, embodiments of a wireless communication device, a wireless communication system, and a wireless communication method according to the present invention will be described in detail with reference to the drawings.

  This embodiment is a wireless communication network configured to have a plurality of wireless communication devices using the present invention, and each wireless communication device is present in the vicinity by multi-hop wireless communication. A wireless communication multi-hop network that delivers a data frame to a target transmission destination (transmission destination wireless communication device) by transferring the data frame to another wireless communication device will be exemplified.

(A-1) Description of Basic Concept In a conventional wireless communication multi-hop network, a wireless communication device is movable, and a change in network topology due to the movement of the wireless communication device causes an update of a routing table in each wireless communication device. Because it is faster than the speed, data may not be transferred successfully. First, this point will be described with reference to the drawings.

  Here, a case of a conventional wireless communication multi-hop network that employs RPL as a route construction protocol is illustrated. That is, each wireless communication device periodically sends and receives DIO messages, updates the routing table (route information) in each wireless communication device, and each wireless communication device transfers a data frame based on the updated route information. The case is illustrated.

  FIG. 4 is an explanatory diagram showing changes in the network topology due to movement of the wireless communication device.

  4A shows a network topology T1 (herein referred to as “pre-movement topology T1”) of the wireless communication apparatuses A to G and R at a certain point in time. A network topology T2 (herein referred to as “post-movement topology T2”) in which the wireless communication devices A, B, F, and G have moved from the topology shown in FIG. Note that the solid lines in FIGS. 4A and 4B indicate that each wireless communication device can communicate.

  As shown in FIG. 4A, it is assumed that a pre-movement topology T1 is constructed at a certain point in time. At this time, it is assumed that route information indicated by a solid line in FIG. 4A is constructed in each of the wireless communication devices A to G and R by RPL. Thereafter, as shown in FIG. 4B, it is assumed that each of the wireless communication devices A, B, F, and G has moved simultaneously to the positions indicated by A ′, B ′, F ′, and G ′.

  In this case, as shown in FIG. 4B, the wireless communication device A at the position A ′ updates the route information based on the DIO message received from the wireless communication device R. The wireless communication device G at the position G ′ updates the route information by receiving the DIO message from the wireless communication device A after the wireless communication device A updates the route information by the DIO message from the wireless communication device R. Will do. In addition, the wireless communication device F at the position of F ′ updates the route information by receiving the DIO message from the wireless communication device G after the route information of the wireless communication device A and the wireless communication device G is updated. Become.

  As described above, the DIO message is periodically and asynchronously transmitted from each wireless communication device. However, if the change in the network topology due to the movement of the wireless communication device is faster than the exchange frequency of the DIO message, a new route information update process is performed. Since the topology is changed, each wireless communication device transfers data based on old route information that does not reflect the new topology. In such a case, data transfer may not reflect the topology at the time of data frame transfer.

  To solve the above problem, there is a method of operating a path construction protocol every time data is transferred, for example, AODV. However, all wireless communication devices in the network follow the reverse route of flooding and flooding in which data is transmitted. Since communication is performed, the communication cost becomes very large.

  As another method, it is conceivable to use a flooding method in which a data frame is transferred so that the data frame reaches all wireless communication apparatuses of a multi-hop network without requiring a route construction protocol. Therefore, data transfer processing when the conventional flooding method is adopted will be described with reference to the drawings.

  FIG. 5 shows an internal configuration of a wireless communication apparatus corresponding to a conventional flooding method. FIG. 6 is a flowchart showing a flooding process procedure in a conventional wireless communication apparatus.

  As shown in FIG. 6, when a certain wireless communication device 200 receives a data frame from another wireless communication device existing in the vicinity (S51), a serial number assigned by the transmission source wireless communication device included in the data frame ( Frame number) is acquired (S52). The frame transfer unit 211 checks the transfer information stored in the storage unit 212 to check whether the received frame has already been processed (S53). If the frame has already been recorded, the frame transfer unit 211 discards the frame. (S54) If the number is not yet recorded, the subsequent number is recorded in the storage unit 212 (S55), the data frame is transferred to the application processing unit 202 (S56), and the data frame is transmitted to the transmission / reception unit 201. Then, the data is further transferred to other wireless communication devices in the vicinity (S57).

  FIG. 7 is a diagram illustrating the arrangement of the wireless communication devices A to G and R and the communication range of the wireless communication device.

  In FIG. 7, a solid line connecting the wireless communication devices indicates that they can communicate with each other. A dotted line r1 indicates a communication range of the wireless communication device R. A dotted line r <b> 2 indicates a communication range of the wireless communication apparatus A.

  When the wireless communication device R transmits a data frame, the wireless communication device R transmits a data frame within the communication range r1, and the wireless communication devices A, C, D, and E that have received the data frame perform the processing of FIG. According to the procedure, the serial number in the data frame is confirmed and recorded, and each of the wireless communication devices A, C, D, and E transfers the data frame to other wireless communication devices in the vicinity.

  For example, when the wireless communication device A transmits a data frame, the data frame transmitted from the wireless communication device A is received by the wireless communication devices R, C, D, and G existing within the communication range r2 of the wireless communication device A. However, since each of the wireless communication devices R, C, and D discards the same data frame that has already been recorded by the processing of S53 in FIG. 6, duplicate transfer can be prevented.

  When such a processing procedure is performed, the data frame is delivered to all the wireless communication devices located within the communicable range without holding the route information for each wireless communication device. In any case, the data frame can be delivered.

  However, since the data transfer by the normal flooding as described above needs to be performed by all wireless communication apparatuses that are not the destination of the data frame, the load due to the communication becomes very high.

  Therefore, in the present invention, a data frame in which the destination is described is forwarded by flooding, and a waiting time is provided for receiving a response frame before the forwarding node forwards to the next hop, and the data frame is transmitted from the destination node within the waiting time. A response frame indicating that it has been received is notified to other wireless communication devices in the vicinity.

  Then, when each wireless communication device receives a response frame within the waiting time, flooding is stopped. By doing so, it is possible to realize data transfer at a reduced communication cost compared to a case where a wireless communication device as a mobile body floods all wireless communication devices in a network in a multi-hop network.

(A-2) Configuration of Embodiment An overall configuration example of a wireless communication multi-hop network (wireless communication system) according to this embodiment can be described with reference to FIG.

  The wireless communication multi-hop network includes a plurality of wireless communication devices A to G and R. Note that the number of wireless communication devices constituting the wireless communication multi-hop network is not particularly limited. The network topology of the wireless communication multi-hop network is not particularly limited. For example, a mesh shape, a tree shape, or the like can be applied.

  Further, some or all of the wireless communication devices A to G and R constituting the wireless communication multi-hop network are movable, for example, mounted on a mobile body. Accordingly, it is assumed that the topology form of the wireless communication multi-hop network can be changed by moving the wireless communication devices A to G and R.

  FIG. 1 is an internal configuration diagram showing the internal configuration of the wireless communication apparatus according to this embodiment.

  In FIG. 1, a wireless communication apparatus 100 according to this embodiment includes a transmission / reception unit 101, a communication control unit 110, an application processing unit 102, a wait timer unit 103, and an antenna unit 104.

[Antenna part 104]
The antenna unit 104 captures an incoming radio wave, converts the radio wave signal into an electrical signal, gives the signal to the transmission / reception unit 101, and transmits the electrical signal from the transmission / reception unit 101 on the radio wave. The antenna unit 104 may be a transmission / reception antenna, or may include a transmission antenna and a reception antenna.

[Transceiver 101]
The transmission / reception unit 101 gives a signal received via the antenna unit 104 to the communication control unit 110 and transmits a transmission signal from the communication control unit 110 via the antenna unit 104. Although not shown, the transmission / reception unit 101 can employ an integrated circuit including a modulation unit, a power amplification unit, a high frequency amplification unit, a demodulation unit, and the like.

  Moreover, the use frequency band of the transmission / reception part 101 of each radio | wireless communication apparatus AG and R can be made into frequencies, such as a 920 MHz band, 2.4 GHz band, and 5 GHz band, for example. The transmission / reception unit 101 may include a transmission unit (transmitter) and a reception unit (receiver).

[Communication control unit 110]
The communication control unit 110 controls transmission / reception of data frames by a flooding method. That is, the communication control unit 110 transmits a communication signal (data frame, response frame) to be transmitted to another wireless communication device by broadcast communication.

  More specifically, when transmitting a data frame, the communication control unit 110 provides the data frame to which the broadcast address is assigned to the transmission / reception unit 101, and transmits the data frame to other wireless communication devices existing in the vicinity. Further, when receiving a data frame transmitted by broadcast, the communication control unit 110 analyzes the received data frame, and the transmission destination (transmission destination address information) of the data frame is the own device (own wireless communication device). In some cases, the user data included in the received data frame is given to the application processing unit 102.

  Further, when the transmission destination of the received data frame is not its own device, the communication control unit 110 gives the data frame to the transmission / reception unit 101 in order to transfer the received data frame to another wireless communication device. At this time, the communication control unit 110 performs data frame transfer standby based on the standby time measured by the wait timer unit 103, and transfers the data frame after the standby time has elapsed. A detailed description of this data frame transfer standby process will be given later.

  Note that the hardware configuration of the communication control unit 110 can be, for example, an integrated circuit including a CPU, ROM, RAM, EEPROM, input / output interface unit, and the like, and the CPU executes a processing program stored in the ROM. As a result, various functions of the communication control unit 110 are implemented.

  1, the communication control unit 110 includes a frame reception unit 111, a response frame transmission unit 112, a frame transfer unit 113, a response frame reception unit 114, a response frame transfer unit 115, and a storage unit 116.

[Frame receiver 111]
The frame receiving unit 111 analyzes a data frame included in the received signal (received packet) from the transmitting / receiving unit 101, and continues the data frame number (frame number) and destination address information included in the received data frame. To receive the data frame.

  Specifically, the frame reception unit 111 collates whether or not the frame number of the received data frame matches the recorded frame number stored in the storage unit 116. If the frame number of the received data frame matches the recorded frame number, it is determined that the received data frame is already received, and the transfer of the received data frame is restricted (for example, the data frame is discarded). To do). As a result, it is possible to prevent transmission of the already received data frame by broadcasting.

  On the other hand, when the frame number of the received data frame does not match the frame number recorded in the storage unit 116, the frame receiving unit 111 determines whether or not the received data frame is a data frame addressed to the own apparatus. The destination address information of the received data frame is analyzed.

  If the destination address information of the received data frame matches the address information of the own device, the frame receiving unit 111 gives the received data frame to the application processing unit 102. At this time, the frame receiving unit 111 records the frame number of the received data frame in the storage unit 116. As a result, even when a data frame received this time is recorded and a data frame with the same frame number is received thereafter, transfer of the same data frame by broadcasting can be prevented.

  On the other hand, when the destination address information of the received data frame does not match the address information of the own device, the frame receiving unit 111 transmits (transfers) the received data frame to another wireless communication device by broadcast. The received data frame is given to the frame transfer unit 113.

[Response frame transmission unit 112]
When the data frame received by the frame receiving unit 111 is a frame addressed to its own device, the response frame transmitting unit 112 forms a response frame addressed to the wireless communication device that is the transmission source of the received data frame, and the response The frame is given to the transmission / reception unit 101. That is, the response frame transmission unit 112 transmits the response frame by broadcast without waiting for the waiting time measured by the wait timer unit 103. As a result, the reception of the data frame addressed to the own apparatus can be recognized by other wireless communication apparatuses existing around the own apparatus.

[Frame transfer unit 113]
When the data frame received by the frame receiving unit 111 is not a frame addressed to the own apparatus, the frame transfer unit 113 transmits the received data frame by broadcast.

  At this time, the wait timer unit 103 measures a predetermined time from the time of reception of the data frame by the frame receiving unit 111. While the wait timer unit 103 measures the waiting time, the frame transfer unit 113 Wait for transfer.

  As will be described later, the response frame receiving unit 114 receives the response frame while waiting for the transfer of the data frame, and the frame number of the response frame matches the frame number of the data frame waiting for transfer. The transfer unit 113 discards the data frame waiting for transfer.

  In this embodiment, a wireless communication device that has received a data frame addressed to itself transmits a response frame to other peripheral wireless communication devices by broadcast without waiting for transfer. On the other hand, when the transmission destination of the data frame is not its own device, that is, when a data frame addressed to another wireless communication device is received, the data frame transfer waits. Then, when the wireless communication device waiting for data frame transfer receives a response frame from another peripheral wireless communication device, it can recognize that the other wireless communication device has received the data frame addressed to itself, Broadcast (ie, flooding) of data frames waiting to be transferred can be stopped. As a result, the amount of data communication to the wireless communication devices in the entire network can be reduced by the flooding.

[Response frame receiving unit 114]
When the reception signal (reception packet) from the transmission / reception unit 101 is a response frame, the response frame reception unit 114 analyzes the frame number included in the response frame and determines whether there is a data frame waiting for transfer. Determine whether.

  Then, there is a data frame waiting for transfer, and it is determined whether or not the frame number of the data frame waiting for transfer matches the frame number of the response frame. When the frame number of the response frame and the frame number of the data frame waiting for transfer match, the response frame receiving unit 114 informs the frame transfer unit 113 of the fact to discard the data frame waiting for transfer. Notice.

  On the other hand, when the frame number of the response frame does not match the frame number of the data frame waiting for transfer, or when there is no data frame waiting for transfer, the response frame receiving unit 114 records the data stored in the storage unit 116. It is determined whether or not the completed frame number matches the frame number of the response frame. This is to prevent transfer of the same response frame.

  When the recorded frame number that matches the frame number of the response frame is recorded in the storage unit 116, the response frame receiving unit 114 further determines whether or not the response frame has already been transferred. Check. When the response has been transferred, the response frame is discarded in order to prevent the response frame from being transferred again. On the other hand, when the response transfer has not been completed, the response frame receiving unit 114 gives the response frame transfer unit 115 the response frame to the response frame transfer unit 115 in order to transfer the response frame.

  When the recorded frame number that matches the frame number of the response frame is not recorded in the storage unit 116, the response frame receiving unit 114 records the frame number of the response frame in the storage unit 116, Discard the response frame.

[Response frame transfer unit 115]
The response frame transfer unit 115 transfers the response frame given from the response frame receiving unit 114.

[Storage unit 116]
The storage unit 116 is a storage area such as a ROM or a RAM for storing processing programs executed in the communication control unit 110 and data necessary for the processing. The storage unit 116 stores the frame number of the data frame received by the wireless communication apparatus 100 and the frame number of the response frame as a recorded frame number. In addition, the storage unit 116 records a response transfer completed flag in association with the frame number of the recorded response frame in order to manage the response frames already transferred in response among the recorded response frames. For a response frame that has already been transferred in response, a response transfer flag is assigned so that the response transfer frame has already been transferred.

[Wait timer unit 103]
The wait timer unit 103 is a waiting time measuring unit that measures a transmission waiting time of a response frame (hereinafter referred to as a waiting time Wf or the like) for a received data frame. The wait timer unit 103 measures a predetermined standby time Wf with the reception of the data frame as a trigger. Here, the length of the predetermined standby time Wf can be appropriately determined according to the operation or the like. For example, the processing time from the reception of the data frame to the transmission of the response frame to the data frame is represented by “Ta”. In this case, it is desirable that the standby time Wf> Ta. This is because the wireless communication device 100 that has received a data frame addressed to itself transmits a response frame by broadcast in order to notify other wireless communication devices that the data frame has been received. This is because another wireless communication device that has received a data frame not addressed to the device temporarily restricts transmission of the response frame.

[Application processing unit 102]
When the communication control unit 110 receives a data frame addressed to itself, the application processing unit 102 performs predetermined application processing based on user data included in the data frame provided from the communication control unit 110. Further, the application processing unit 102 gives the user data to the communication control unit 110 when transmitting user data obtained by performing the application processing to another wireless communication device.

(A-3) Operation of Embodiment Next, a wireless communication method in a wireless communication multi-hop network according to this embodiment will be described in detail with reference to the drawings.

  In the following, first, processing operations when each wireless communication device 100 receives a data frame transmitted from another wireless communication device will be described with reference to the drawings. Thereafter, processing operations when each wireless communication device 100 receives a response frame transmitted from another wireless communication device will be described with reference to the drawings.

(A-3-1) Data Frame Reception Processing FIG. 2 is a flowchart showing an operation of data frame reception processing according to the embodiment.

  First, one of the wireless communication devices constituting the wireless communication multi-hop network illustrated in FIG. 4 transmits a data frame to a target transmission destination by broadcast. At this time, the format of the frame includes, for example, information indicating a frame type (for example, information indicating whether a data frame or a response frame is included), address information of a transmission source (for example, a MAC address), and a target transmission destination. Address information (for example, MAC address), a frame number indicating sequential number information of frames, user data, and the like. Note that the format of the frame is not limited to that including the above information, and other information may be included in the extended area, for example.

  When another wireless communication device transmits a communication packet including a data frame by broadcast, the wireless communication device existing in the vicinity receives the communication packet transmitted by the other wireless communication device.

  In the wireless communication apparatus 100 that has received the communication packet, the transmission / reception unit 101 receives the data frame, and provides the data frame to the communication control unit 110. In the communication control unit 110, the frame reception unit 111 receives the data frame (S1), analyzes the data frame, and serial number information of the frames assigned by the wireless communication device as the transmission source included in the data frame (Frame number) is extracted (confirmed) (S2). Then, the frame reception unit 111 refers to the recorded frame number stored in the storage unit 116 and collates whether or not the frame number of the received data frame matches the recorded frame number of the storage unit 116. (S3).

  If the frame number of the received data frame matches the recorded frame number, it is determined that the received data frame is an already received data frame, and the received data frame is discarded (S4).

  On the other hand, when the frame number of the received data frame matches the recorded frame number, the frame receiving unit 111 records the frame acquired from the received data frame in order to record that the data frame is a received frame. The number is recorded in the recorded frame of the storage unit 116 (S5).

  Next, in order to determine whether or not the received data frame is addressed to the own apparatus, the frame receiving unit 111 acquires transmission destination address information included in the received data frame, and transmits the transmission destination address. It is determined whether the information is address information of another wireless communication device (S6).

  Then, when the transmission address information of the data frame is not another wireless communication device (that is, when the transmission address information of the data frame is addressed to the own device), application processing is executed based on user data included in the data frame Therefore, the frame receiving unit 111 transfers the data frame to the application processing unit 102 (S7). Also, the frame receiving unit 111 notifies the response frame transmitting unit 112 that the data frame is addressed to the own apparatus. In response to this, the response frame transmitting unit 112 forms a response frame for the received data frame, and transmits the response frame by broadcast (S8). In this way, the wireless communication device that has received the data frame addressed to itself transmits the response frame without waiting for the waiting time Wf related to the transmission of the response frame, thereby allowing other wireless communication devices existing in the vicinity to On the other hand, it can be recognized that the data frame addressed to the own apparatus has been received.

  Here, a method of forming a response frame will be described. The response frame transmission unit 112 sets the “transmission source address information” included in the received data frame as the “transmission destination address information” of the response frame, and the address information of the device itself (that is, the “transmission destination address information” of the received data frame) “)” As the “source address information” of the response frame. Further, the response frame transmission unit 112 inserts the “frame number” included in the received data frame as it is as the “frame number” of the response frame. By inserting the frame number in this way, it is possible to identify the response frame for the received data frame.

  On the other hand, when the destination address information of the received data frame is the address information of another wireless communication device in S6 (that is, when the destination address information of the data frame is not addressed to the own device), the received data frame is transmitted. In order to transfer the packet to the other wireless communication apparatus, the frame reception unit 111 notifies the frame transfer unit 113 to that effect.

  Here, the wait timer unit 103 measures a predetermined standby time Wf using the reception of the data frame as a trigger. The frame transfer unit 113 waits for the transfer of the data frame while the wait timer unit 103 is measuring the predetermined standby time Wf (S9). This process of waiting for transfer of a data frame not addressed to the own apparatus to another wireless communication apparatus is also referred to as frame transfer wait process. The waiting time for this frame weight process is generally longer than the time Ta until a response frame is transmitted in response to reception of a data frame in flooding by broadcast.

  Then, after the waiting time Wf by the wait timer 103 has elapsed, the frame transfer unit 113 transmits a data frame addressed to another wireless communication device by broadcasting (S10). That is, by waiting for transfer of a data frame addressed to another wireless communication apparatus for the waiting time Wf, only the wireless communication apparatus that has received the data frame addressed to itself transmits a response frame, and data by other wireless communication apparatuses Wait for frame transfer processing.

(A-3-2) Response Frame Reception Processing Next, processing operations when each wireless communication device 100 receives a response frame transmitted from another wireless communication device will be described with reference to the drawings.

  FIG. 3 is a flowchart illustrating an operation of a response frame reception process according to the embodiment.

  In each wireless communication device 100, when the transmission / reception unit 101 receives a response frame transmitted from another wireless communication device, the transmission / reception unit 101 gives the communication control unit 110 a response frame. In the communication control unit 110, the response frame receiving unit 114 receives the response frame (S11), analyzes the received response frame, and extracts a frame number included in the response frame. Then, the response frame reception unit 114 collates (confirms) whether or not the frame number of the data frame waiting for transfer matches the frame number of the response frame by measuring the waiting time Wf by the wait timer unit 103 ( S12, S13).

  When the frame number of the received response frame matches the frame number of the data frame waiting for transfer, the response frame receiving unit 114 notifies the frame transfer unit 113 to that effect. In response to this, the frame transfer unit 113 discards the data frame waiting for transfer (S20). That is, when a response frame having the same frame number is received while waiting to transfer a data frame, it can be recognized that another wireless communication apparatus 100 that is the transmission destination of the data frame has correctly received the data frame. . For this reason, the data frame waiting for transfer is discarded, and the transfer of the data frame waiting for transfer is stopped. This can also be said to stop the flooding of data frames in the entire wireless communication multi-hop network.

  When the received response frame frame number does not match the frame number of the data frame waiting for transfer, or when not waiting for transfer (that is, when there is no data frame waiting for transfer), the response frame receiving unit 114 Then, referring to the recorded frame number in the storage unit 116, it is checked whether there is a frame number that matches the frame number included in the received response frame (S14).

  When the frame number of the received response frame is not recorded in the recorded frame number of the storage unit 116, the response frame receiving unit 114 sets the frame number of the received response frame as the recorded frame number of the storage unit 116. Further, a response transfer completed flag corresponding to the frame number is assigned (S15), and the response frame is discarded (S17). This is a case where the wireless communication apparatus 100 has received a response frame for a data frame that does not record that it has been received this time. In this case, since the wireless communication apparatus does not need to transmit a response frame, the response frame is discarded. In addition, there is a possibility that a response frame with the same frame number will be received again thereafter. In this case, if nothing is recorded, the transfer process of the response frame may be repeated. Therefore, the response frame receiving unit 114 records the frame number of the response frame in the storage unit 116 and sets the response transfer completed flag.

  In S14, when the frame number of the received response frame is recorded in the recorded frame number of the storage unit 116, or when the data frame waiting for transfer in S20 is discarded, the response frame receiving unit 114 Then, the response transfer completed flag corresponding to the recorded frame number in the storage unit 116 is confirmed (S16). If the response transfer completed flag is set (Yes in S16), the response frame is discarded (S17).

  In S16, when the response transfer completed flag is not set (No in S16), the response frame receiving unit 114 records the response transfer completed flag for the recorded frame number in the storage unit 116 (S18), and notifies the response frame. Notify the transfer unit 115. In response, the response frame transfer unit 115 transmits the response frame by broadcasting (S19). Thereby, the received response frame can be transmitted to other wireless communication apparatuses existing in the vicinity.

(A-3-3) Data frame transfer process (first example)
Next, an example (first example) of data frame transfer processing in a wireless communication multi-hop network will be described with reference to FIGS. 2, 3, 4, and 7.

  As described above, FIG. 4A shows the topology T1 before movement, and FIG. 4B shows the topology T2 after movement.

  FIG. 7 illustrates a case where the wireless communication device R delivers a data frame to the wireless communication device A in the state of the post-movement topology T2 of FIG.

  The wireless communication device R assigns to the data frame a frame number that is a serial number that increases by 1 each time a data frame is transmitted, and sets the address information of the wireless communication device A that is the final destination as “destination address information”. The address information of the wireless communication device R that is the transmission source is transmitted as “transmission source address information” so as to be included in the data frame.

  When the wireless communication device R transmits a data frame, each of the wireless communication devices A, C, D, and E located within the communication range r1 of the wireless communication device R receives the data frame. Since any of the wireless communication devices A, C, E, and D is a data frame having a frame number that is received for the first time, the frame number that is the serial number of the frame is not stored but stored in the storage unit 116 (see FIG. 2). S1, S2, S3 (YES), S5).

  Since the destination address information of the received data frame is addressed to itself, the wireless communication device A transfers it to the application processing unit 102 (S7), and the response frame transmission unit 112 transmits the response frame by broadcast (S8). .

  On the other hand, each of the wireless communication devices C, D, and E is in a data frame transfer standby state while the wait timer unit 103 measures the standby time Wf because the data frame destination address information is another wireless communication device. (S9).

  While waiting for data frame transfer in each of the wireless communication devices C, D, and E, the wireless communication device A transmits a response frame to other peripheral wireless communication devices. That is, the wireless communication devices C, D, and R within the communication range r2 of the wireless communication device A receive the response frame.

  The wireless communication device R that is the transmission source of the data frame confirms that the data frame has reached the wireless communication device A that is the destination by receiving the response frame.

  On the other hand, since the wireless communication devices C and D receive a response frame including the same frame number as the data frame while waiting for a data frame, the wireless communication devices C and D discard the data frame in the standby state ( S11, S12, S13 (Yes), S20 in FIG.

  On the other hand, since the wireless communication device E is outside the communication range of the wireless communication device A and is in a position where it cannot receive a response frame from the wireless communication device A, it transfers the data frame after waiting for transfer (S9 and S10 in FIG. 2). . At this time, in the case of conventional flooding, the wireless communication devices C and D also transmit data frames to be flooded. However, when the present invention is applied, transmission of the data frames of the wireless communication devices C and D can be suppressed. it can.

  Note that the response frame whose destination address information is the address information of the wireless communication device A is transferred from the wireless communication device A to the wireless communication device. Thereby, it is confirmed that the data frame transmitted by the wireless communication device R as the transmission source has reached the wireless communication device A as the destination.

(A-3-4) Data frame transfer process (second example)
Next, an example (second example) of data frame transfer processing in the wireless communication multi-hop network will be described with reference to FIGS. 2, 3, 4, and 7.

  In the second example, a case where the wireless communication device R delivers a data frame to the wireless communication device B in FIG. 7 will be described.

  The wireless communication device R assigns to the data frame a frame number that is a serial number that increases by 1 each time a data frame is transmitted, and sets the address information of the wireless communication device B that is the final destination as “destination address information”. The address information of the wireless communication device R that is the transmission source is transmitted as “transmission source address information” so as to be included in the data frame.

  As in the first example, the wireless communication device R transmits a data frame, and each of the wireless communication devices A, C, D, and E existing within the communication range r1 of the wireless communication device R receives the data frame. To do.

  Here, each wireless communication device A, C, D, E transmits the data frame by broadcast after the elapse of the data frame transfer waiting time because the transmission destination address of the received data frame is another wireless communication device. (S1, S2, S3 (No), S5, S6 (Yes), S9, S10 in FIG. 2).

  When the wireless communication device D transmits a data frame by broadcast, the wireless communication devices R, A, and B existing in the communication range r3 of the wireless communication device D receive the data frame.

  Here, since the destination address information of the received data frame is addressed to the own device, the wireless communication device B transfers it to the application processing unit 102 (S7), and the response frame transmission unit 112 transmits the response frame by broadcast. (S8).

  When receiving the response frame from the wireless communication device B, the wireless communication device F located within the communication range of the wireless communication device B stores the frame number of the response frame and the response transfer completed flag in the storage unit 116 ( S11, S12, S13 (No), S14, S15 in FIG. Thereby, after that, the data frame to which the same frame number was assigned and the response frame can be discarded.

  Here, the wireless communication device G exists within the communication range r2 of the wireless communication device A. The wireless communication device A transmits the data frame by broadcast after the transfer standby Wf elapses, and the wireless communication device G stores the frame number of the data frame received from the wireless communication device A in the storage unit 116. .

  At this time, it is assumed that the wireless communication device G is located within the communication range of the wireless communication device B. In this case, the wireless communication device G has received the data frame from the wireless communication device A, is performing frame transfer wait processing, and is waiting for the transfer of the data frame (S9 in FIG. 2). In this state, when the wireless communication device G receives a response frame having the same frame number from the wireless communication device B (S11, S12, S13 in FIG. 3), the data frame waiting for transfer is discarded (S20), and the response A frame transfer process is performed (S14 (Yes), S16 (Yes), S17).

  On the other hand, when the wireless communication device G is located outside the communication range of the wireless communication device B, the wireless communication device G does not receive a response frame from the wireless communication device B. The data frame is transferred (S9 and S10 in FIG. 2). In this case, in both the wireless communication apparatuses B and F, the data frame and the response frame of the frame number are regarded as being subjected to the response process, and the transfer process is not performed.

  The response frame in which the destination address information is the address information of the wireless communication device R is transferred from the wireless communication device B to the wireless communication device D, and from the wireless communication device D to the wireless communication device R. As a result, it is confirmed that the data frame transmitted by the wireless communication device R as the transmission source has reached the wireless communication device B as the destination.

(A-4) Effects of the Embodiment As described above, according to this embodiment, the wireless communication apparatus can transfer data frames by flooding without exchanging route information. On the other hand, regarding the communication cost which becomes a problem in flooding, efficient communication can be performed without wasteful transfer by processing the response frame prior to the frame transfer process.

(B) Other Embodiments In the above-described embodiments, various modified embodiments of the present invention have been mentioned, but the present invention can also be applied to the following modified embodiments.

  (B-1) In the embodiment, the operation flow shown in FIG. 3 is an example of a response frame reception process, and is not limited to this process. For example, in S14 and S15 in FIG. 3, it is described that the response frame is transferred only to the wireless communication device through which the data frame has passed, but S14 and S15 in FIG. 3 are omitted and the conditional expression in S13 does not match. In this case, the process may proceed to S16. As a result, although the communication cost of flooding increases, it is possible to return the response frame on a route different from the route through which the data frame passes even when the movement of the wireless communication device is large.

DESCRIPTION OF SYMBOLS 100 ... Wireless communication apparatus, 101 ... Transmission / reception part, 110 ... Communication control part, 102 ... Application processing part, 103 ... Wait timer part, 104 ... Antenna part, 111 ... Frame reception part, 112 ... Response frame transmission part 112 ... Frame transfer 114, a response frame reception unit, 115, a response frame transfer unit, 106, a storage unit.

Claims (8)

In a wireless communication device that wirelessly communicates communication signals by broadcast,
Transmitting and receiving means for transmitting and receiving communication signals;
A waiting time measuring means for measuring a predetermined waiting time for a transmission time related to transfer of a communication signal received by the transmitting / receiving means;
Depending on the transmission destination of the communication signal received by the transmission / reception means, the transmission of the communication signal or the transmission of the response signal is controlled, and based on the standby time measured by the standby time measurement means, Communication control means for performing transfer processing of the received communication signal. The communication control means is
A storage unit for storing frame information included in communication signals received in the past;
When the frame information of the communication signal received this time is not stored in the storage unit, and the transmission destination information of the communication signal is not its own device, after the waiting time measured by the waiting time measuring means has elapsed, The wireless communication apparatus according to claim 1, further comprising: a frame transfer unit that transmits a communication signal. The communication control means is
As a signal received this time, a response signal to the communication signal is received, and the response signal reception unit determines whether the frame information of the response signal matches the frame information of the communication signal on standby,
The frame transfer unit regulates transmission of the waiting communication signal when frame information of the response signal matches frame information of the waiting communication signal. Wireless communication device.   The communication control means, when the frame information of the communication signal received this time is not stored in the storage unit and the transmission destination information of the communication signal is its own device, without waiting for the waiting time, The wireless communication apparatus according to claim 2, further comprising a response signal transmission unit that transmits a response signal to the communication signal.   3. The frame control unit according to claim 2, further comprising: a frame receiving unit that restricts transmission of the communication signal received this time when frame information of the communication signal received this time is stored in the storage unit. Or the wireless communication device according to 4. The storage unit stores flag information indicating whether processing related to transfer or response is performed in association with frame information of the received communication signal,
If the frame information of the received response signal is not stored in the storage unit, the response signal receiving unit stores the frame information of the response signal and the flag information in the storage unit, and then transfers the response signal. The wireless communication device according to claim 2, wherein the wireless communication device is regulated. In a wireless communication system that wirelessly communicates communication signals by broadcasting between a plurality of wireless communication devices,
Each wireless communication device
Transmitting and receiving means for transmitting and receiving communication signals;
A waiting time measuring means for measuring a predetermined waiting time for a transmission time related to transfer of a communication signal received by the transmitting / receiving means;
Depending on the transmission destination of the communication signal received by the transmission / reception means, the transmission of the communication signal or the transmission of the response signal is controlled, and based on the standby time measured by the standby time measurement means, A wireless communication system comprising: communication control means for performing a transfer process of the received communication signal. In a wireless communication method for wirelessly communicating a communication signal by broadcast between a plurality of wireless communication devices,
Each wireless communication device
Measure a predetermined waiting time for the transmission time related to the transfer of the communication signal received by the transmission / reception means for transmitting and receiving the communication signal,
Depending on the transmission destination of the communication signal received by the transmission / reception means, the transmission of the communication signal or the transmission of the response signal is controlled, and based on the standby time measured by the standby time measurement means, A wireless communication method characterized by performing transfer processing of the received communication signal.

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