JP2009239488A - Radio communication apparatus, radio communication system, radio communication method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely detect the communication state in a radio multi-hop network. <P>SOLUTION: A radio communication apparatus 100 configuring the radio multi-hop network is provided with: a transmission control section 20 for transmitting the information indicating the communication state of the network in accordance with priority of communication to the other devices configuring the radio multi-hop network; and a flag information acquiring section 14 for acquiring the information indicating the communication state transmitted from each of the other devices per priority of communication. This configuration makes it possible to surely recognize whether or not the communication having high priority is performed in the radio multi-hop network, and the optimum control according to the communication state can be executed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  Recently, a wireless multi-hop network technology that can easily expand the communication area between terminals in an ad hoc network in which each node is connected by a wireless network is known.

  In a general wireless multi-hop network, a communication path between nodes is determined by a routing protocol, and communication between nodes is performed according to the determined path. Therefore, each node can transmit the packet to the destination by transmitting the packet to the node determined by the routing protocol with respect to a different destination for each packet.

  Many of the general wireless networks represented by IEEE802.11b use a CSMA / CA access method that is a DCF (Distributed Coordination Function) at each node to compete for resources of a limited wireless band with neighboring nodes. Communication.

JP 2005-524318 A

  For example, when stream transmission of moving pictures or the like is performed in a wireless multi-hop network, the delay of end-to-end communication is increased unlike a conventional P2P type wireless network. For this reason, it is necessary to preferentially flow stream-type traffic in distinction from bulk transmission such as file transfer by FTP (File Transfer Protocol).

  However, when such a process for controlling traffic is applied to a wireless multi-hop network, it is difficult to grasp which route the traffic flows through. For this reason, it is difficult to perform traffic control according to priority in a wireless multi-hop network.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is a new and improved wireless multi-hop network that can reliably detect the communication status in the network. The present invention provides a wireless communication device, a wireless communication system, a wireless communication method, and a program.

  In order to solve the above-described problem, according to an aspect of the present invention, a wireless communication device that forms a wireless multi-hop network, the network communication status is shown to other devices that form the wireless multi-hop network. Wireless communication comprising: a communication status transmission unit that transmits information according to communication priority; and a communication status acquisition unit that acquires, for each communication priority, information indicating the communication status transmitted from another device An apparatus is provided.

  According to the above configuration, information indicating the communication status of the network is transmitted according to the priority of communication to the other devices constituting the wireless multi-hop network, and information indicating the communication status transmitted from the other devices is communicated. Acquired for each priority. Therefore, it is possible to reliably recognize whether or not high-priority communication is performed in the wireless multi-hop network, and it is possible to perform optimal control according to the communication status.

  Moreover, you may further provide the communication control part which controls communication of an own apparatus based on the information which shows the said communication condition acquired from the other apparatus. According to this configuration, it is possible to optimally control the communication of the own device according to the priority of the communication status in the network.

  The communication control unit may reduce communication of the own device having a low priority when communication with a high priority is performed based on information indicating the communication status. According to such a configuration, when communication with high priority such as video distribution is performed, communication of the own device with low priority is reduced, so priority is given to communication with high priority in the wireless multi-hop network. Can be performed.

  A flag information creating unit that creates information indicating the communication status as flag information; the communication status transmitting unit transmits the flag information to another device; and the communication control unit is acquired from the other device. Based on the flag information, communication of the own device may be controlled. According to such a configuration, since the information indicating the communication status of the own apparatus is created and transmitted as flag information, the data amount of the information indicating the communication status can be minimized.

  The communication status transmission unit may broadcast the flag information to other devices. According to such a configuration, unnecessary traffic information of the own device is not transmitted, so that an increase in overhead can be suppressed.

  The flag information may include a flag indicating the communication status of the own device. According to such a configuration, it is possible to acquire a communication status of traffic directly related to another device, and to control communication of the own device based on this.

  Further, the flag information may include a flag indicating a communication status between two other devices other than the own device. According to this configuration, it is possible to acquire the communication status of traffic that is not directly related to the own device from other devices, and to control communication of the own device based on this.

  In order to solve the above problems, according to another aspect of the present invention, a wireless communication system including a plurality of wireless communication devices constituting a wireless multi-hop network, wherein the wireless communication device is a wireless multi-hop device. A communication status transmission unit that transmits information indicating the communication status of the network to other devices configuring the network, and communication that acquires, for each communication priority, information indicating the communication status transmitted from the other device. A wireless communication system including a status acquisition unit is provided.

  According to the above configuration, in a wireless communication system including a plurality of wireless communication devices configuring a wireless multihop network, information indicating the communication status of the network is a communication priority with respect to other devices configuring the wireless multihop network. The information indicating the communication status transmitted from the other device is acquired for each communication priority. Therefore, it is possible to reliably recognize whether or not high-priority communication is performed in the wireless multi-hop network, and it is possible to perform optimal control according to the communication status.

  In order to solve the above problem, according to another aspect of the present invention, there is provided a wireless communication method in a wireless communication device constituting a wireless multi-hop network, which is a method for other devices constituting a wireless multi-hop network. A step of transmitting information indicating the communication status of the network; a step of acquiring information indicating the communication status transmitted from another device for each priority of communication; and the communication status acquired from the other device. And a step of controlling communication of the device itself based on the information.

  According to the above configuration, in the wireless communication method in the wireless communication device configuring the wireless multi-hop network, the information indicating the communication status of the network is in accordance with the communication priority with respect to the other devices configuring the wireless multi-hop network. Information indicating the communication status transmitted and transmitted from the other device is acquired for each communication priority, and communication of the own device is controlled based on the information indicating the communication status acquired from the other device. Therefore, it is possible to reliably recognize whether or not high-priority communication is being performed within the wireless multi-hop network, and optimally control the communication of the device according to the priority of the communication status in the network. It becomes possible to do.

  In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a program in a wireless communication device constituting a wireless multi-hop network, which is a network for other devices constituting the wireless multi-hop network. Based on information indicating the communication status acquired from another device, means for acquiring the communication status transmitted from another device, information indicating the communication status transmitted from another device, for each priority of communication A program for causing a computer to function as a means for controlling communication of its own device is provided.

  According to the above configuration, in the program in the wireless communication device configuring the wireless multi-hop network, information indicating the communication status of the network is transmitted according to the communication priority to the other devices configuring the wireless multi-hop network. The information indicating the communication status transmitted from the other device is acquired for each communication priority, and the communication of the own device is controlled based on the information indicating the communication status acquired from the other device. Therefore, it is possible to reliably recognize whether or not high-priority communication is being performed within the wireless multi-hop network, and optimally control the communication of the device according to the priority of the communication status in the network. It becomes possible to do.

  According to the present invention, it is possible to provide a wireless communication device, a wireless communication system, a wireless communication method, and a program that can reliably detect a communication state in a wireless multi-hop network.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[Outline of wireless communication system]
FIG.1 and FIG.2 is a schematic diagram for demonstrating the outline | summary of the radio | wireless communications system 200 which concerns on this embodiment. As illustrated in FIGS. 1 and 2, the wireless communication system 200 includes a plurality of nodes #A to #E. Each of the nodes #A to #E includes a wireless communication device 100 whose position is fixed or movable. Each of the nodes #A to #E has a function capable of relaying and transmitting signals transmitted from other nodes, thereby configuring a wireless multi-hop network.

  In the wireless communication system 200, video data, audio data, and other data files can be transmitted according to their priorities. For example, FIG. 1 shows a case where there are two traffics (traffic X and traffic Y) in a wireless multi-hop network, and the priority of traffic is traffic X> traffic Y. In this case, both traffic X and traffic Y pass through node #C. For this reason, by observing the queue length and the amount of packet transmission / reception at the node #C at the node #C, the traffic Y can be suppressed, and a certain amount of flow control according to the priority can be performed.

  On the other hand, FIG. 2 shows a case where there are two traffic patterns (traffic X and traffic Z) different from FIG. 1 and the priority of traffic is traffic X> traffic Z. In this case, although it is necessary to perform flow control in the node #D, the communication of the traffic Z also affects the communication between the node #B and the node #C and between the node #C and the node #D. For example, a signal RTS (request to send) notifying that preparation for communication is ready from the node #E to the node #D is transmitted, and a signal CTS (clear to send) indicating permission of transmission from the node #D to the node #E is transmitted. When transmitted, the node #C receives the CTS transmitted from the node #D, and the communication between the node #B and the node #C and between the node #C and the node #D is stopped. For this reason, the traffic X reaching the node #D from the node #C becomes small, and it may be determined that the traffic Z need not be suppressed in the node #D. In this case, traffic Y with low priority cannot be reduced, and it becomes impossible to give priority to stream delivery with high priority.

  Therefore, assuming that autonomous distributed flow control is performed in a wireless multi-hop network, in the case of FIG. 2, even if the queue length and the amount of packet transmission / reception in the local node are observed, the traffic is based on the information. Cannot be controlled. In the case of FIG. 2, there is a high possibility that flow control based on traffic control only at the local station node does not function, and information exchange regarding traffic is required between nodes.

  On the other hand, if it is assumed that information is exchanged between all nodes and flow control is performed, it is difficult to know which route the traffic flows through, so how to communicate between which nodes. Difficulty in determining whether it will affect. For this reason, even if information about the queue length and packet transmission / reception traffic at all nodes can be acquired, it is difficult to determine which information is used to control traffic at the local station. In addition, when information is exchanged between all nodes, there is a concern that the overhead may increase rapidly as the number of nodes existing in the wireless multi-hop network increases.

  Therefore, in this embodiment, the queue length and the packet transmission / reception amount are observed for each traffic priority at each node, and the traffic status is notified to the neighboring nodes as flag information. In addition, in the peripheral node that has received the flag information, the result of adding up the received flag information is further notified to the peripheral node as flag information. As a result, it becomes possible to perform autonomous distributed flow control in the wireless multi-hop network based on the flag information notified from the neighboring nodes in each node.

  Further, in this embodiment, in order to minimize an increase in overhead due to control information, the information amount itself is suppressed to be small by notifying the neighboring nodes using information related to traffic of the local station as a flag. Further, information on the traffic of the local station node is further notified to neighboring nodes by the neighboring node that has received the information. As a result, information related to the traffic of the local station node is propagated from the local station node to a node two hops away.

  As a result, the traffic information is transmitted only to the peripheral nodes existing up to the node that is two hops away, which will actually affect the communication of the local node, and is unnecessary based on the traffic information of the local node. Traffic control can be prevented from being performed. Further, since unnecessary traffic information of the local node is not transmitted, an increase in overhead can be suppressed. Hereinafter, embodiments of the present invention will be described in detail.

[Configuration of wireless communication device]
FIG. 3 is a functional block diagram showing the configuration of the wireless communication apparatus 100 according to the present embodiment. As illustrated in FIG. 3, the wireless communication device 100 includes a communication unit 12, a flag detection unit 14, a storage unit 16, a transmission data generation unit 18, a transmission control unit 20, and a flag information creation unit 22.

  The communication unit 12 is an interface with an external device such as the wireless communication device 100, and has functions as a transmission unit and a reception unit that transmit and receive various types of information to and from other wireless communication devices. For example, the communication unit 12 down-converts a high-frequency radio signal transmitted from another radio communication device 100 into a baseband signal, and converts the baseband signal into a bit string. Further, the communication unit 12 converts the bit string of the transmission data generated by the transmission data generation unit 18 into a baseband signal, converts the baseband signal into a high-frequency radio signal, and transmits it to another radio communication device 100. .

  The communication unit 12 may have a wireless communication function defined in IEEE (Institute of Electrical and Electronic Engineers) 802.11a, b, g, etc., or MIMO (Multiple Input) defined in IEEE 802.11n. Multiple Output) communication function may be provided. Further, the communication unit 12 may have a communication function corresponding to WiMAX (Worldwide Interoperability for Microwave Access) planned for IEEE 802.16.

  The flag detection unit 14 has a function of detecting flag information broadcast from another wireless communication device 100. The wireless communication device 100 corresponding to each of the nodes #A to #E broadcasts the flag information of the own device at a predetermined cycle. The flag detection unit 14 can recognize the flag information received by the communication unit 12.

  The storage unit 16 is a storage medium on which various types of information are recorded. Examples of the various information include flag information of the own device, flag information received from another wireless communication device 100, and the like. The storage unit 16 also has a function as a buffer that temporarily stores data packets to be transmitted. The memory | storage part 16 can be comprised from non-volatile memories, such as EEPROM and EPROM, and volatile memories, such as DRAM, for example.

  The transmission data generation unit 18 generates a message for transmission from the communication unit 12. The transmission data generation unit 18 generates a data packet in order to transmit video, audio, and the like to the other wireless communication device 100.

  The transmission control unit 20 performs control when the data packet generated by the transmission data generation unit 18 and the flag information generated by the flag information generation unit 22 are broadcast-transmitted from the communication unit 12 to another wireless communication device 100. . Further, the transmission control unit 20 controls data transmission by the communication unit 12 based on the flag information detected by the flag detection unit 14. The transmission control unit 20 performs control so as to suppress transmission with low priority when it is detected from the flag information that communication with high priority is performed in the adjacent node.

  The flag information creation unit 22 creates flag information according to the transmission status and reception status of the own device in order to broadcast the flag information to other wireless communication devices 100. The flag information will be described in detail below.

[About flag information]
FIG. 4 is a schematic diagram showing a flag for each node to acquire traffic. In the present embodiment, in order for each node to detect traffic, eight flags shown in FIG. 4 are defined. Hereinafter, each flag will be described.

F_TX_TRAFFIC_H, F_TX_TRAFFIC_L:
This flag is set when the queue length or the amount of transmitted packets in the local node is large. In the present embodiment, by using two types of threshold values (TH_TX_TRAFFIC_H, TH_TX_TRAFFIC_L (where TH_TX_TRAFFIC_H> TH_TX_TRAFFIC_L)) for the amount of transmission traffic, the surrounding nodes are notified of the transmission traffic occurrence status in their own node. Note that F_TX_TRAFFIC_H indicates that the amount of transmission traffic generated is larger than F_TX_TRAFFIC_L.

F_RX_TRAFFIC_H, F_RX_TRAFFIC_L:
This flag is set when the received packet amount at the local station node is large. In the present embodiment, the reception traffic amount is notified to surrounding nodes by using two types of threshold values (TH_RX_TRAFFIC_H, TH_RX_TRAFFIC_L (where TH_RX_TRAFFIC_H> TH_RX_TRAFFIC_L)). Note that F_RX_TRAFFIC_H indicates that the amount of received traffic generated is larger than that of F_RX_TRAFFIC_L.

F_TX_TRAFFIC_H_OR, F_TX_TRAFFIC_L_OR:
This flag is set when a notification by the F_TX_TRAFFIC_H and F_TX_TRAFFIC_L flags is received from a peripheral node. By setting this flag, it is possible to notify the neighboring nodes that the notification by the F_TX_TRAFFIC_H and F_TX_TRAFFIC_L flags has been received.

F_RX_TRAFFIC_H_OR, F_RX_TRAFFIC_L_OR:
This flag is set when a notification by the F_RX_TRAFFIC_H and F_RX_TRAFFIC_L flags is received from a peripheral node. By setting this flag, it is possible to notify the neighboring nodes that the notification by the F_RX_TRAFFIC_H and F_RX_TRAFFIC_L flags has been received.

  Next, flow control using the above-described eight flags will be described. First, a processing method related to the notification flag will be described. FIG. 5 is a flowchart showing notification flag setting processing in each wireless communication device 100. The flow control starts by observing the traffic situation occurring at each node at each node and notifying the surrounding nodes as a flag for each traffic priority X. In the present embodiment, two types of flags corresponding to the traffic are set for each of the transmission status and the reception status, but more flags can be set according to the traffic. In addition to flag information, the actual data amount related to transmission / reception may be notified as information notified to the peripheral nodes.

  First, in step S1, the traffic amount check for all priorities X is started. Here, it is assumed that the transmission traffic amount (queue length or transmission packet amount) related to the priority X is TX_TRAFFIC [X], and the reception traffic amount (reception packet amount) related to the priority X is RX_TRAFFIC [X].

  In step S2, it is determined whether or not TX_TRAFFIC [X]> TH_TX_TRAFFIC_H. If TX_TRAFFIC [X]> TH_TX_TRAFFIC_H, the F_TX_TRAFFIC_H flag is set in step S3.

  If TX_TRAFFIC [X] ≦ TH_TX_TRAFFIC_H in step S2, the process proceeds to step S4, and it is determined whether TX_TRAFFIC [X]> TH_TX_TRAFFIC_L. If TX_TRAFFIC [X]> TH_TX_TRAFFIC_L, the F_TX_TRAFFIC_L flag is set in step S5.

  Thus, the flag (F_TX_TRAFFIC_H or F_TX_TRAFFIC_L) corresponding to the transmission traffic amount related to the priority X is set by the processing up to step S5.

  Next, a process of setting a flag (F_RX_TRAFFIC_H or F_RX_TRAFFIC_L) corresponding to the received traffic amount related to the priority X is performed by the processes of steps S6 to S9.

  First, in step S6, it is determined whether or not RX_TRAFFIC [X]> TH_RX_TRAFFIC_H. If RX_TRAFFIC [X]> TH_RX_TRAFFIC_H, an F_RX_TRAFFIC_H flag is set in step S7.

  If RX_TRAFFIC [X] ≦ TH_RX_TRAFFIC_H in step S6, the process proceeds to step S8 to determine whether RX_TRAFFIC [X]> TH_RX_TRAFFIC_L. If RX_TRAFFIC [X]> TH_RX_TRAFFIC_L, the F_RX_TRAFFIC_L flag is set in step S9.

  In this way, the flag (F_RX_TRAFFIC_H or F_RX_TRAFFIC_L) corresponding to the received traffic amount related to the priority X is set by the processing up to step S9.

  Next, processing of setting F_TX_TRAFFIC_H_OR and F_TX_TRAFFIC_L_OR flags is performed by the processing of steps S10 to S13.

  First, in step S10, it is determined whether or not the F_TX_TRAFFIC_H flag notification corresponding to the priority X is received from the peripheral node. If the F_TX_TRAFFIC_H flag notification is received from the peripheral node, the F_TX_TRAFFIC_H_OR flag is set in step S11.

  Next, in step S12, it is determined whether or not the F_TX_TRAFFIC_L flag notification corresponding to the priority X is received from the peripheral node. If the F_TX_TRAFFIC_L flag notification is received from the peripheral node, the F_TX_TRAFFIC_L_OR flag is set in step S13.

  Next, processing of setting F_RX_TRAFFIC_H_OR and F_RX_TRAFFIC_L_OR flags is performed by the processing of steps S14 to S17.

  First, in step S14, it is determined whether or not the F_RX_TRAFFIC_H flag notification corresponding to the priority X is received from the peripheral node. If the F_RX_TRAFFIC_H flag notification is received from the peripheral node, the F_RX_TRAFFIC_H_OR flag is set in step S15.

  Next, in step S16, it is determined whether or not the F_RX_TRAFFIC_L flag notification corresponding to the priority X is received from the peripheral node. If the F_RX_TRAFFIC_L flag notification is received from the peripheral node, the F_RX_TRAFFIC_L_OR flag is set in step S17.

  With the above processing, the traffic amount check for all priority levels X is completed (step S18). Thereby, flag information composed of eight flags is created. As described above, as a method for notifying flag information to neighboring nodes, a broadcast packet such as a Hello message is used in this embodiment.

  The peripheral node that has received the notification flag information notifies the result of the traffic situation obtained by observing the traffic situation of the local station node as a flag, and simultaneously notifies the OR flag that the notification flag has been received from the peripheral node. In addition, each node creates flag information for each priority of traffic (traffic X, Y, Z, W) and notifies the neighboring nodes.

  As described above, as a result of exchanging information between nodes using the flag information regarding the traffic status, for example, receiving some notification flag from the neighboring nodes regarding the traffic higher than the priority of the traffic generated in the local node. Can do. In this case, by performing traffic control in the own node according to the type of the notification flag, it is possible to perform flow control so that traffic with high priority is transmitted and received with priority in the wireless multi-hop network.

  A state in which the flag propagates in each node when the flag is set by the above method will be described in detail. First, how the notification flag propagates in the situation shown in FIG. 1 will be described.

  In the situation shown in FIG. 1, it is assumed that traffic occurs in the order shown in FIG. That is, traffic Y (node # C → node #D) having a low priority such as a data file is generated first, and then traffic X (node # A → node # B → node #) having a high priority such as video data is generated next. Assume that C → node #D) occurs. The priority of traffic can be determined in advance according to the system, and as described above, for example, the priority is increased for stream transmission such as moving images, and the priority is decreased for bulk transmission such as file transfer.

  FIG. 7 shows a state where traffic Y first occurs in the situation shown in FIG. FIG. 8 is a schematic diagram showing a transition state of flag information (notification flag table) when traffic Y occurs. In FIG. 8, the arrangement of flags in each of the priorities A and B is the same as in FIG. That is, for each priority A and B, in the right column, the flags are arranged from the top in the order of TX_TRAFFIC_H_OR, TX_TRAFFIC_L_OR, RX_TRAFFIC_H_OR, and RX_TRAFFIC_L_OR. In the left column, flags are arranged from the top in the order of TX_TRAFFIC_H, TX_TRAFFIC_L, RX_TRAFFIC_H, and RX_TRAFFIC_L. In FIG. 8, for convenience of explanation, dots are attached to flags whose state has changed at the timing when the time (time 1-1 to time 1-3) switches. The arrangement of the flags and the display of the dots are the same in FIGS. 10, 11, 14, 16, and 17. The notification flag table is notified to neighboring nodes through a broadcast such as a Hello message.

  First, as shown in FIG. 7, it is assumed that traffic Y corresponding to the priority B that exceeds TH_TX_TRAFFIC_H occurs from the node #C to the node #D. In this case, as shown in FIG. 8, first, the TX_TRAFFIC_H flag with priority B is set based on the traffic status of the own node at node #C (time 1-1).

  After that, the node #B and the node #D that have received the TX_TRAFFIC_H flag with the priority B notified from the node #C set the TX_TRAFFIC_H_OR flag with the priority B. Further, since the node #D receives the traffic from the node #C, the RX_TRAFFIC_H flag having the priority B is set based on the traffic state of the local node (time 1-2).

  Next, the RX_TRAFFIC_H_OR flag of the priority B is set in the node #C and the node #E that have received the RX_TRAFFIC_H flag of the priority B notified from the node #D (time 1-3). At this time, in the node #C, the traffic situation of the local station node is recognized as the RX_TRAFFIC_H_OR flag via the peripheral node (here, the node #D), but since the priority B is the same, the priority B There is no restriction on the local traffic.

  FIG. 9 shows a state in which traffic X occurs after traffic Y shown in FIG. 7 occurs in the situation shown in FIG. FIGS. 10 and 11 are schematic diagrams showing the transition state of the notification flag table when traffic X occurs after traffic Y occurs. Here, it is assumed that traffic X corresponding to priority A exceeding TX_TH_TRAFFIC_H has occurred. At time (2-1), the flag information related to priority B is inherited from time (1-3) in FIG. First, the TX_TRAFFIC_H flag with the priority A is set based on the traffic situation of the own node at the node #A (time 2-1 in FIG. 10).

  After that, the node #B that has received the TX_TRAFFIC_H flag with the priority A notified from the node #A sets the TX_TRAFFIC_H_OR flag with the priority A and receives and forwards the traffic from the node #A. The TX_TRAFFIC_H and RX_TRAFFIC_H flags of the priority A are set based on the traffic status of (No. 2-2 in FIG. 10).

  Next, the node #A and the node #C that have received the TX_TRAFFIC_H and RX_TRAFFIC_H flags of the priority A notified from the node #B raise the TX_TRAFFIC_H_OR and RX_TRAFFIC_H_OR flags of the priority A. Further, since node #C receives and forwards traffic from node #B, it sets TX_TRAFFIC_H and RX_TRAFFIC_H flags of priority A based on the traffic status of the local node (time 2-3 in FIG. 10).

  Further, in the node #C, the traffic status in the own node (the TX_TRAFFIC_H, RX_TRAFFIC_H, TX_TRAFFIC_H_OR and RX_TRAFFIC_H_OR flags of the priority A) and the traffic status from the neighboring nodes (of the priority A received from the node #B) TX_TRAFFIC_H, RX_TRAFFIC_H, and TX_TRAFFIC_H_OR flag) can recognize that priority A traffic is generated in the wireless multi-hop network. For this reason, the node #C performs control to the traffic Y having the priority level B in its own node.

  More specifically, node #C can recognize that priority A traffic is generated in the wireless multi-hop network from the TX_TRAFFIC_H, RX_TRAFFIC_H, and TX_TRAFFIC_H_OR flags of priority A received from node #B. For this reason, the node #C can also control the traffic Y with the priority level B based only on the traffic status notified from the neighboring nodes.

  Here, it is assumed that the node #C performs control so that the traffic Y is smaller than TH_TX_TRAFFIC_H and exceeds TH_TX_TRAFFIC_L. As a result, at time 2-3, the TX_TRAFFIC_H flag of priority B at the node #C is changed to the TX_TRAFFIC_L flag, the TX_TRAFFIC_H flag is set to “0”, and the TX_TRAFFIC_L flag is set to “1”. In this way, it is grasped from the information of the notification flag received from the peripheral node that the traffic with high priority is generated, and as a result, the traffic with low priority (traffic Y at node #C) is controlled. Is possible.

  In the present embodiment, the process of recognizing that high priority traffic is generated from the flag information is performed by the flag information acquisition unit 14, and the traffic control based on this is performed by the transmission control unit 20. Further, the creation of flag information by the processing of FIG. 5 is performed by the flag information creation unit 22. The functional blocks shown in FIG. 5 can be configured by hardware, or an arithmetic processing unit (CPU) and software (program) for causing it to function. When these functional blocks are configured by an arithmetic processing unit and software, the program can be stored in a recording medium such as the storage unit 16 included in the wireless communication device 100.

  In this embodiment, the traffic Y is controlled by the node #C. However, for example, when the traffic Y is transferred along the route of the node # C → the node # B → the node #A, the node #C located on the route , #B, and #A can control the traffic, and for example, the traffic may be controlled to decrease stepwise along the route.

  Then, the TX_TRAFFIC_H and the RX_TRAFFIC_H_OR flags of the priority A are set in the node #B and the node #D that have received the TX_TRAFFIC_H and the RX_TRAFFIC_H flag of the priority A notified from the node #C based on the change of the notification flag in the node #C. If the flag is already set, the flag is left as it is. Further, since the node #D receives the traffic from the node #C, the RX_TRAFFIC_H flag having the priority A is set based on the traffic status of the local node. Further, in Node #D, RX_TRAFFIC_H of priority B is changed to RX_TRAFFIC_L and TX_TRAFFIC_H_OR from the traffic status of the local station node due to the restriction of priority B traffic in node #C and the change of the notification flag related to priority B. Is changed to TX_TRAFFIC_L_OR (time 2-4 in FIG. 11).

  Thereafter, RX_TRAFFIC_H_OR of priority B is received at node #C and node #E that have received that the flag relating to priority B notified from node #D has been changed from RX_TRAFFIC_H to RX_TRAFFIC_L due to a change in notification flag at node #D. Is changed to RX_TRAFFIC_L_OR, and the RX_TRAFFIC_H flag with the priority A is further received from the node #C at the node #E, so the RX_TRAFFIC_H_OR flag with the priority A is set (time 2-5 in FIG. 11).

  As described above, in the situation shown in FIG. 1, the node #C can control to reduce the traffic Y with low priority based on the flag information of the peripheral nodes acquired by broadcasting.

  Next, how the notification flag propagates in the situation shown in FIG. 2 will be described. In the situation shown in FIG. 2, it is assumed that traffic occurs in the order shown in FIG. That is, it is assumed that traffic Z having a low priority such as a data file is generated first, and traffic X having a high priority such as video data is generated next.

  FIG. 13 shows a state in which traffic Z is first generated in the situation shown in FIG. FIG. 14 is a schematic diagram showing a transition state of the notification flag table when traffic Z occurs.

  First, as shown in FIG. 13, it is assumed that traffic Z corresponding to the priority B that exceeds TH_TX_TRAFFIC_H occurs from the node #E to the node #D. In this case, as shown in FIG. 14, first, in the node #E, the TX_TRAFFIC_H flag with the priority B is set based on the traffic situation of the own node (time 3-1).

  After that, the node #D that has received the TX_TRAFFIC_H flag with the priority B notified from the node #E sets the TX_TRAFFIC_H_OR flag with the priority B. Further, since the node #D receives the traffic from the node #E, the RX_TRAFFIC_H flag with the priority B is set based on the traffic state of the local node (time 3-2).

  Next, the RX_TRAFFIC_H_OR flag with the priority B is set at the node #C and the node #E that have received the RX_TRAFFIC_H flag with the priority B notified from the node #D (time 3-3). At this time, in the node #E, the traffic situation of the local station node is recognized as the RX_TRAFFIC_H_OR flag via the peripheral node (here, the node #D), but since the priority B is the same, the priority B There is no restriction on the local traffic.

  FIG. 15 shows a state where traffic X occurs after the traffic Z shown in FIG. 13 occurs in the situation shown in FIG. FIGS. 16 and 17 are schematic diagrams showing transition states of the notification flag table when traffic X occurs after traffic Z occurs. Here, assuming that traffic X corresponding to priority A exceeding TX_TH_TRAFFIC_H has occurred, first, the TX_TRAFFIC_H flag of priority A is set based on the traffic status of the local node at node #A (time 4-1 in FIG. 16). .

  After that, the node #B that has received the TX_TRAFFIC_H flag with the priority A notified from the node #A sets the TX_TRAFFIC_H_OR flag with the priority A, and the node #B receives and forwards the traffic from the node #A. Therefore, the TX_TRAFFIC_H and RX_TRAFFIC_H flags of priority A are set based on the traffic status of the local station node (time 4-2 in FIG. 16).

  Next, the node #A and the node #C that have received the TX_TRAFFIC_H and RX_TRAFFIC_H flags of the priority A notified from the node #B raise the TX_TRAFFIC_H_OR and RX_TRAFFIC_H_OR flags of the priority A. Further, since node #C receives and forwards traffic from node #B, it sets TX_TRAFFIC_H and RX_TRAFFIC_H flags of priority A based on the traffic status of its own node (time 4-3 in FIG. 16).

  Next, the node #B and the node #D that have received the TX_TRAFFIC_H and RX_TRAFFIC_H flags of the priority A notified from the node #C raise the TX_TRAFFIC_H_OR and RX_TRAFFIC_H_OR flags of the priority A. Further, since the node #D receives the traffic from the node #C, the RX_TRAFFIC_H flag of the priority A is set based on the traffic status of the local node (time 4-4 in FIG. 16).

  Next, the RX_TRAFFIC_H_OR flag of the priority A is set in the node #C and the node #E that have received the RX_TRAFFIC_H flag of the priority A notified from the node #D. If the flag is already set, the flag is set as it is. (Time 4-5 in FIG. 17)

  Further, the node #E indicates that the traffic of the priority A is generated in the wireless multi-hop network, the traffic status in the own node (the RX_TRAFFIC_H_OR flag of the priority A is set) and the traffic from the peripheral nodes. Since it can be recognized from the situation (RX_TRAFFIC_H and RX_TRAFFIC_H_OR flags of priority A received from node #D), control to traffic Y of priority B is performed at its own node.

  More specifically, the node #E can recognize that priority A traffic is generated in the wireless multi-hop network from the RX_TRAFFIC_H and RX_TRAFFIC_H_OR flags of the priority A received from the node #D. For this reason, the node #E can control the traffic Z with the priority level B based only on the traffic status notified from the neighboring nodes.

  Here, in node #E, control is performed so that traffic Z is smaller than TH_TX_TRAFFIC_H and exceeds TH_TX_TRAFFIC_L. As a result, at time 4-5, the TX_TRAFFIC_H flag of priority B at the node #E is changed to the TX_TRAFFIC_L flag, the TX_TRAFFIC_H flag is set to “0”, and the TX_TRAFFIC_L flag is set to “1”.

  In this way, unlike in the case of FIG. 1, even when the traffic of high priority level is not directly generated in the local node, the notification is received from the peripheral node that the high priority traffic is generated. As a result, it is possible to control the low priority traffic (traffic Z at node #E).

  Subsequently, TX_TRAFFIC_H_OR of priority B is changed to TX_TRAFFIC_L_OR at node #D that has received that the flag related to priority B notified from node #E has been changed from TX_TRAFFIC_H to TX_TRAFFIC_L due to a change in notification flag at node #E Is done. Also, due to the restriction on the traffic with the priority B at the node #E, the RX_TRAFFIC_H with the priority B is changed to the RX_TRAFFIC_L at the node #D based on the traffic status of the own node (time 4-6 in FIG. 17).

  Then, RX_TRAFFIC_H_OR of the priority B is received at the node #C and the node #E that have received that the flag related to the priority B notified from the node #D has been changed from RX_TRAFFIC_H to RX_TRAFFIC_L from the change of the notification flag at the node #D. Is changed to RX_TRAFFIC_L_OR (time 4-7 in FIG. 17).

  FIG. 18 shows a case where traffic X and traffic W exist in the wireless multi-hop network, and node #D that is the end point of traffic X and node #E that is the end point of traffic W are different nodes separated from each other. . Here, it is assumed that the priority of traffic X is higher than the priority of traffic W. In this embodiment, even in such a case, the node #E acquires flag information from the node #D, and particularly detects the RX_TRAFFIC_H_OR flag, thereby recognizing the presence of traffic X with high priority. it can. Thereby, the node #E can suppress the transmission of the CTS to the node #F, and can reliably suppress the suppression of the traffic X due to the transmission of the CTS.

  As described above, in the present embodiment, by setting the OR flag, information related to the traffic of the local station node is further notified to neighboring nodes by the neighboring node that has received the information. As a result, information related to the traffic of the local station node is propagated from the local station node to a node two hops away. Therefore, as shown in FIG. 18, since information indicating that high-priority traffic X is transmitted from node #C is transmitted to node #E that is two hops away, low-priority traffic is transmitted at node #E. It becomes possible to suppress.

  As described above, in this embodiment, in the wireless multi-hop network, for the purpose of autonomous distributed flow control, each node #A to #E relates to traffic such as queue length and packet transmission / reception amount for each traffic priority. Observe information. Then, the traffic status is notified to the peripheral node as flag information, and the peripheral node receiving the information notifies the peripheral node of the result of totaling the received flag information as flag information. Accordingly, it is possible to realize autonomous distributed flow control in the wireless multi-hop network based on flag information notified from neighboring nodes in each node.

  As a result, it is not necessary to exchange information with all nodes in the wireless multi-hop network more than necessary, and broadcast messages such as Hello messages that are periodically transmitted and received at each node can be used. Thereby, an increase in overhead due to an increase in the number of nodes existing in the wireless multi-hop network such as a flooding message can be reliably suppressed. As a result, the limited network capacity of the wireless multi-hop network can be used effectively, and can be used in a form to which flow control is applied.

  In addition, because the information is exchanged by flags, the amount of information itself can be smaller than when exchanging specific information such as queue length and packet transmission / reception amount, thereby suppressing an increase in overhead for flow control. Can do.

  Further, since information is not exchanged in a predetermined procedure such as signaling as information exchange between nodes, a system having high compatibility with an existing system can be obtained.

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

It is a schematic diagram for demonstrating the outline | summary of the radio | wireless communications system which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the outline | summary of the radio | wireless communications system which concerns on embodiment of this invention. It is a functional block diagram which shows the structure of a radio | wireless communication apparatus. It is a schematic diagram which shows the flag for each node to acquire traffic. It is a flowchart which shows the setting process of the notification flag in each radio | wireless communication apparatus. It is a schematic diagram which shows the order which a traffic generate | occur | produces in the situation shown in FIG. FIG. 2 is a schematic diagram showing a state where traffic Y is first generated in the situation shown in FIG. 1. FIG. 3 is a schematic diagram showing a transition state of flag information (notification flag table) when traffic Y occurs in the situation shown in FIG. 1. FIG. 8 is a schematic diagram showing a state in which traffic X occurs after traffic Y shown in FIG. 7 occurs in the situation shown in FIG. 1. FIG. 3 is a schematic diagram showing a transition state of a notification flag table when traffic X occurs after traffic Y occurs in the situation shown in FIG. 1. FIG. 3 is a schematic diagram showing a transition state of a notification flag table when traffic X occurs after traffic Y occurs in the situation shown in FIG. 1. FIG. 3 is a schematic diagram illustrating an order in which traffic occurs in the situation illustrated in FIG. 2. FIG. 3 is a schematic diagram showing a state in which traffic Z is first generated in the situation shown in FIG. 2. FIG. 3 is a schematic diagram showing a transition state of a notification flag table when traffic Z occurs in the situation shown in FIG. 2. FIG. 14 is a schematic diagram illustrating a state in which traffic X is generated after the traffic Z illustrated in FIG. 13 is generated in the situation illustrated in FIG. 2. FIG. 3 is a schematic diagram showing a transition state of a notification flag table when traffic X occurs after traffic Z occurs in the situation shown in FIG. 2. FIG. 3 is a schematic diagram showing a transition state of a notification flag table when traffic X occurs after traffic Z occurs in the situation shown in FIG. 2. It is a schematic diagram which shows the situation where the traffic X and the traffic W exist in the radio | wireless multihop network.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Wireless communication apparatus 200 Wireless communication system 12 Communication part 14 Flag information creation part 20 Transmission control part 22 Flag information creation part

Claims (10)

A wireless communication device constituting a wireless multi-hop network,
A communication status transmission unit that transmits information indicating the communication status of the network according to the priority of communication with respect to other devices constituting the wireless multi-hop network,
A communication status acquisition unit that acquires information indicating the communication status transmitted from another device for each priority of the communication;
A wireless communication device comprising:   The wireless communication apparatus according to claim 1, further comprising a communication control unit that controls communication of the own apparatus based on information indicating the communication status acquired from another apparatus.   3. The communication control unit according to claim 2, wherein the communication control unit reduces communication of the own device having a low priority when communication with a high priority is performed based on the information indicating the communication status. The wireless communication device described. A flag information creating unit that creates information indicating the communication status as flag information;
The communication status transmission unit transmits the flag information to another device,
The wireless communication apparatus according to claim 2, wherein the communication control unit controls communication of the own apparatus based on the flag information acquired from another apparatus.   The wireless communication apparatus according to claim 4, wherein the communication status transmission unit broadcasts the flag information to another apparatus.   5. The wireless communication apparatus according to claim 4, wherein the flag information includes a flag indicating a communication status of the own apparatus.   The wireless communication apparatus according to claim 4, wherein the flag information includes a flag indicating a communication status between two other apparatuses other than the own apparatus. A wireless communication system comprising a plurality of wireless communication devices constituting a wireless multi-hop network,
The wireless communication device
A communication status transmission unit that transmits information indicating the communication status of the network to other devices constituting the wireless multi-hop network;
A communication status acquisition unit that acquires information indicating the communication status transmitted from another device for each priority of the communication;
A wireless communication system comprising: A wireless communication method in a wireless communication device constituting a wireless multi-hop network,
Transmitting information indicating the communication status of the network to other devices constituting the wireless multi-hop network;
Obtaining information indicating the communication status transmitted from another device for each priority of the communication;
Based on information indicating the communication status acquired from another device, controlling the communication of the device itself;
A wireless communication method comprising: A program in a wireless communication device constituting a wireless multi-hop network,
Means for transmitting information indicating the communication status of the network to other devices constituting the wireless multi-hop network;
Means for acquiring information indicating the communication status transmitted from another device for each priority of communication;
Means for controlling communication of the own device based on information indicating the communication status acquired from another device;
As a program to make the computer function.

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