JP2007288578A - System and apparatus for wireless communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication system capable of enhancing communication efficiency as a whole. <P>SOLUTION: The wireless communication system comprises a plurality of wireless communication apparatuses. Each wireless communication apparatus includes: a transmission wait time measurement section 11 for measuring a transmission wait time; and a communication processor 3 that replaces a transmission wait time included in a received routing search request or a routing searching response with the transmission wait time measured by the transmission wait time measurement, and externally broadcasts the result when the routing search request or the routing search response for routing establishment received from the other wireless communication apparatus is not addressed to its own apparatus, and the transmission wait time included in the routing search request or the routing search response is shorter than the transmission wait time measured by the transmission wait time measurement section, and transmits data adjusted to have a transmission data amount in response to the transmission wait time included in the routing search response, when the routing search response from the other wireless communication apparatus is addressed to its own apparatus. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wireless communication system in which a plurality of wireless communication devices that are components of a wireless ad hoc network simultaneously perform wireless communication with an arbitrary partner, and more particularly, wireless communication in which the topology of a network changes with time due to movement of each wireless communication device. The present invention relates to a system and a wireless communication apparatus.

  The wireless ad hoc network is realized by using wireless communication means such as a wireless local area network (LAN) and an ad hoc routing protocol. The wireless LAN is realized in accordance with the IEEE 802.11a / b / g standard.

  In a wireless LAN, even when a plurality of wireless communication devices perform transmission simultaneously, in order to prevent data collision as much as possible, CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) (Avoidance) method is adopted. In this CSMA / CA system, a wireless communication apparatus that wants to transmit data monitors the communication status of the communication path, and starts transmission when the communication path is free. At this time, if a plurality of wireless communication apparatuses start transmission at the same time, data collides in the communication path and breaks, so that retransmission is performed after waiting for a random time.

  Even in such a wireless ad hoc network using a CSMA / CA wireless LAN, transmission data may not reach the transmission destination from the transmission source. There are several reasons for this, but one of them is due to the fact that it is impossible to completely avoid the occurrence of a collision caused by a plurality of wireless communication apparatuses transmitting simultaneously in a wireless LAN. This phenomenon is more likely to occur as the amount of communication traffic increases.

  Another cause is due to degradation of the line quality. In a wireless LAN, there are cases where the distance between wireless communication devices is large or the influence of multipath / interference is large, so that the line quality deteriorates and transmission data does not reach. When the transmission data does not arrive in this way, data is retransmitted in the wireless LAN. If the message does not arrive even after being retransmitted, the retransmission is repeated a preset number of times, and if it still does not arrive, it is processed as a transmission failure.

  As a technique for solving such a problem that transmission data does not reach from the transmission source to the transmission destination, Patent Document 1 discloses a multi-hop wireless communication system that enables optimal route establishment in consideration of link quality. Yes. In this multi-hop wireless communication system, a relay node receives an RREQ, obtains a link quality metric of a route from the transmission source node to the own node, registers this in the RREQ, and transfers it.

The destination node receives the RREQ, obtains the link quality metric of the route from the transmission source node to the own node, registers this in the RREP, and returns it. The destination node that has received the same RREQ by another route returns an RREP in response to the RREQ having an excellent link quality metric. A source node that has received the same RREP via a different route generates route information based on the RREP having an excellent link quality metric.
JP 2005-33557 A

  In order to solve the above-described problems of the conventional wireless communication system, it is conceivable to actively suppress the amount of transmission data when communication traffic is high. In addition, when the line quality is poor, it is conceivable to actively change the transmission data size.

  By the way, a wireless LAN used in a wireless ad hoc network is not an “infrastructure mode” in which each wireless communication device communicates via an access point, but an “ad hoc mode” in which wireless communication devices directly communicate with each other. Operate.

  In infrastructure mode, all data transfer between wireless communication devices is performed via an access point, so QoS (Quality of Service) control such as changing the allocated bandwidth according to the communication priority at the access point is performed. Although it is relatively easy to perform, in the ad hoc mode, since there is no access point, it is difficult to control the transmission data amount and transmission data size transmitted by each wireless communication device.

  Various types of ad hoc routing protocols have been devised, and can be classified into a reactive type, a proactive type, and a hybrid type that combines these types. Each of these types has a difference in the method of determining the route, but is independent of the control of the transmission data amount and the transmission data size.

  As described above, in the conventional wireless ad hoc network, when transmission data does not reach the transmission destination from the transmission source, the cause is not taken into consideration, and it is simply attempted to recover by repeating retransmission. There is a problem that is bad.

  The subject of this invention is providing the radio | wireless communications system and radio | wireless communication apparatus which can improve the communication efficiency as a whole.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a wireless communication system including a plurality of wireless communication devices, and each of the plurality of wireless communication devices measures a transmission waiting time. When a route search request or route search response for route establishment received from another measurement device and another wireless communication device is not addressed to itself, a transmission wait time included in the route search request or route search response is a transmission wait time measurement unit If the transmission wait time is smaller than the transmission wait time measured in step 1, the transmission wait time included in the received route search request or route search response is replaced with the transmission wait time measured by the transmission wait time measurement unit and broadcasted to the outside. When the route search response received from another wireless communication device is addressed to itself, the amount of transmission data corresponding to the transmission waiting time included in the route search response is set. Characterized by comprising a communication processing unit which transmits the integer data.

  The invention according to claim 2 is a wireless communication system including a plurality of wireless communication devices, each of the plurality of wireless communication devices includes a received signal level measuring unit that measures a received signal level, When the route search request or route search response for route establishment received from the wireless communication apparatus is not addressed to itself, the received signal level measured by the received signal level measurement unit is included in the route search request or route search response. If the level is higher than the level, the received signal level included in the received route search request or route search response is replaced with the received signal level measured by the received signal level measuring unit and broadcasted to the outside, and another wireless communication device When the route search response received from is addressed to itself, the transmission data size is set according to the received signal level included in the route search response. Characterized by comprising a communication processing unit for transmitting the adjusted data.

  According to a third aspect of the present invention, in the first aspect of the invention, each of the plurality of wireless communication devices further includes a received signal level measuring unit that measures a received signal level, and the communication processing unit further includes: When a route search request or route search response for establishing a route received from another wireless communication device is not addressed to itself, the received signal level included in the route search request or route search response is measured by the received signal level measuring unit. If the received signal level is greater than the received signal level, the received signal level included in the received route search request or route search response is replaced with the received signal level measured by the received signal level measurement unit, and broadcasted to the outside. When the route search response received from the communication device is addressed to itself, the transmission data size corresponds to the received signal level included in the route search response. And transmitting the data urchin adjusted.

  Furthermore, the invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the plurality of wireless communication devices are connected by a wireless ad hoc network.

  According to a fifth aspect of the present invention, there is provided a wireless communication device used in a wireless communication system including a plurality of wireless communication devices, a transmission waiting time measuring unit for measuring a transmission waiting time, and another wireless communication device. When the route search request or route search response for establishing a route received from is not addressed to itself, the transmission wait time included in the route search request or route search response is based on the transmission wait time measured by the transmission wait time measuring unit. If it is smaller, the transmission waiting time included in the received route search request or route search response is replaced with the transmission waiting time measured by the transmission waiting time measurement unit and broadcasted to the outside, and another wireless communication device When the route search response received from is addressed to itself, the data is adjusted so that the transmission data amount corresponds to the transmission waiting time included in the route search response. Characterized by comprising a communication processing unit which transmits the data.

  The invention according to claim 6 is a wireless communication device used in a wireless communication system composed of a plurality of wireless communication devices, the reception signal level measuring unit for measuring the reception signal level, and reception from another wireless communication device. When the route search request or route search response for establishing a route is not addressed to itself, the received signal level included in the route search request or route search response is greater than the received signal level measured by the received signal level measuring unit The received signal level included in the received route search request or route search response is replaced with the received signal level measured by the received signal level measuring unit, broadcasted to the outside, and received from another wireless communication device If the route search response is addressed to itself, the transmission data size will be in accordance with the received signal level included in the route search response. Characterized by comprising a communication processing unit which transmits the adjusted data.

  The invention according to claim 7 is the invention according to claim 5, further comprising a received signal level measuring unit for measuring a received signal level, wherein the communication processing unit further establishes a path received from another wireless communication device. If the received signal level included in the route search request or the route search response is greater than the received signal level measured by the received signal level measurement unit when the route search request or the route search response for A route search received from another wireless communication device by replacing the received signal level included in the received route search request or route search response with the received signal level measured by the received signal level measurement unit and broadcasted to the outside. When the response is addressed to itself, the data is adjusted so that the transmission data size corresponds to the received signal level included in the route search response. And transmitting the data.

  According to an eighth aspect of the present invention, in the wireless communication device according to any one of the fifth to seventh aspects, the wireless communication device is connected to the other wireless communication device through a wireless ad hoc network.

  According to the first aspect of the present invention, the communication traffic amount on the route from the transmission source to the transmission destination is determined by the transmission data amount by the largest transmission waiting time among the transmission waiting times of the wireless communication devices existing on the route. Since the data adjusted so as to have the determined transmission data amount is transmitted, it is possible to prevent data from staying in one wireless communication device on the path by suppressing the transmission data amount. As a result, the communication efficiency of the entire wireless communication system can be improved.

  According to the second aspect of the present invention, the channel quality of the route from the transmission source to the transmission destination is determined based on the reception signal level of the wireless communication apparatus existing on the route, and the determined transmission data size is determined. Since the data adjusted so as to be transmitted is transmitted, the transmission rate of transmission data can be improved by shortening the transmission data size, and the communication efficiency of the entire wireless communication system can be improved.

  According to invention of Claim 3, the radio | wireless communications system which has each effect of invention of Claim 1 mentioned above and invention of Claim 2 together can be provided.

  According to the fourth aspect of the present invention, since a plurality of wireless communication devices are connected by a wireless ad hoc network, a wireless communication system in which the topology of the network changes with time can be constructed using, for example, a wireless LAN.

  The inventions according to claims 5 to 8 can obtain the same effects as the effects of claims 1 to 4.

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

  The wireless communication device used in the wireless communication system according to the first embodiment of the present invention has a wireless LAN function and an ad hoc routing protocol. In the following, it is assumed that a reactive AODV (Ad hoc On-Demand Distance Vector) routing protocol is used as the ad hoc routing protocol.

  When searching for a route from a data transmission source to a transmission destination using the AODV routing protocol, a wireless communication device that relays a “route search request” or a “route search response” uses information and a line indicating communication traffic. Information indicating the quality is inserted into the route search request or route search response data.

  As information indicating the amount of communication traffic, a transmission waiting time when data is transmitted by the wireless LAN, for example, an average of transmission waiting times in the latest 10 seconds is used. As the information indicating the amount of communication traffic, for example, the sum of transmission waiting times in the latest 10 seconds can be used. Further, the period (time) for calculating the transmission waiting time is not limited to 10 seconds and can be arbitrarily determined. Further, the information indicating the amount of communication traffic may be calculated by averaging the transmission waiting time at the last several transmissions.

  As the information indicating the line quality, a received signal level when receiving data by the wireless LAN is used. Specifically, the received signal level when the wireless communication apparatus receives a route search request or a route search response is used as information indicating the line quality.

  FIG. 1 is a block diagram illustrating a configuration of a wireless communication device used in the wireless communication system according to the first embodiment of the present invention. This wireless communication apparatus includes an antenna 1, a wireless transmission / reception unit 2, and a communication processing unit 3.

  The antenna 1 converts a transmission signal sent as an electric signal from the radio transmission / reception unit 2 into a radio wave and emits it into the air, converts a radio wave received from the air into an electric signal, and sends it to the radio transmission / reception unit 2 as a reception signal. send.

  The wireless transmission / reception unit 2 includes a wireless LAN module such as a wireless LAN board or a wireless LAN card, and realizes functions of layer 1 and layer 2 in an OSI (Open Systems Interconnection) hierarchical model. Specifically, the wireless transmission / reception unit 2 generates a transmission signal by modulating a signal transmitted from the communication processing unit 3 and converting the signal into a high-frequency signal while performing communication management such as framing and error control. Send to 1. Further, the radio transmission / reception unit 2 converts the received signal sent from the antenna 1 into an intermediate frequency signal, demodulates it, and sends it to the communication processing unit 3.

  The wireless transmitting / receiving unit 2 includes a transmission waiting time measuring unit 11 and a received signal level measuring unit 12. When a transmission request is sent from the communication processing unit 3, the wireless transmission / reception unit 2 performs carrier sense in order to check whether another wireless communication device is transmitting prior to transmission. If it is determined that the wireless communication apparatus is transmitting, transmission is performed after waiting for a certain time. Therefore, when the communication traffic amount increases, the transmission waiting time becomes longer.

  The transmission waiting time measuring unit 11 measures the time from when a transmission request is sent from the communication processing unit 3 to when transmission is actually performed, and calculates the average of transmission waiting times in the latest 10 seconds. The transmission waiting time calculated by the transmission waiting time measuring unit 11 is stored as information indicating the amount of communication traffic in a memory (not shown) provided in the wireless transmission / reception unit 2. The transmission waiting time stored in the memory is read by the communication processing unit 3.

  The reception signal level measurement unit 12 measures the level of the reception signal transmitted from the antenna 1. Specifically, the received signal level measurement unit 12 measures the received signal level when a route search request or a route search response is received. The received signal level measured by the received signal level measuring unit 12 is stored as information indicating the line quality in a memory (not shown) provided in the radio transmitting / receiving unit 2. The received signal level stored in the memory is read by the communication processing unit 3.

  The communication processing unit 3 is composed of, for example, a CPU board. Functionally, the communication processing unit 3 includes a wireless transmission / reception unit driver 21, an IP processing unit 22, an ad hoc routing processing unit 23, and an upper layer processing unit 24.

  The wireless transmission / reception unit driver 21 controls the wireless transmission / reception unit 2. Specifically, the wireless transmission / reception unit driver 21 transmits / receives data to / from the wireless transmission / reception unit 2 and sets parameters for the wireless transmission / reception unit 2 in response to a request from the IP processing unit 22 or the ad hoc routing processing unit 23. The state of the wireless transmission / reception unit 2 is monitored.

  The IP processing unit 22 executes IP (Internet Protocol) processing among layer 3 processing in the OSI hierarchical model. That is, the IP processing unit 22 adds an IP header (see FIG. 3) to the data sent from the ad hoc routing processing unit 23 and sends the data to the wireless transmission / reception unit driver 21 to request transmission. In addition, the IP processing unit 22 deletes the IP header from the data received from the wireless transmission / reception unit driver 21 and sends it to the ad hoc routing processing unit 23.

  FIG. 3 is a diagram showing a transmission / reception data format of data used in the ad hoc routing protocol. This data includes a layer 2 header, an IP header, ad hoc routing data (for example, a route search request, a route search response, etc.), a transmission waiting time, a received signal level, and a layer 2 trailer. Among these, the transmission waiting time and the received signal level are specific to the wireless communication system according to the first embodiment of the present invention.

  The ad hoc routing processing unit 23 executes routing (route control) processing among layer 3 processing in the OSI hierarchical model. Specifically, the ad hoc routing processing unit 23 performs processing of a routing protocol, and executes processing of transmitting / receiving data to / from the IP processing unit 22 after determining a route. The processing of the ad hoc routing processing unit 23 will be described in detail later.

  The upper layer processing unit 24 executes processing defined by layers 4 and higher in the OSI hierarchical model. Specifically, the upper layer processing unit 24 performs data transmission / reception with the ad hoc routing processing unit 23 in layers 4 and higher. For example, the upper layer processing unit 24 receives “an upper limit value of the transmission data amount corresponding to traffic” from the ad hoc routing processing unit 23 and executes a process of limiting the transmission data amount so as not to exceed the upper limit value. Here, the transmission data amount means the amount of data to be transmitted per unit time.

  FIG. 2 is a functional block diagram showing a detailed configuration of the ad hoc routing processing unit 23. The ad hoc routing processing unit 23 includes an ad hoc routing protocol processing unit 31, a route search request / route search response transmission / reception unit 32, a transmission waiting time processing unit 33, a received signal level processing unit 34, a network traffic determination unit 35, and a network line quality determination. The unit 36 is configured.

  Although the detailed description is omitted, the ad hoc routing protocol processing unit 31 executes processing according to the ad hoc routing protocol in response to a request from the upper layer processing unit 24 or the route search request / route search response transmission / reception unit 32. To do.

  In response to the request from the ad hoc routing protocol processing unit 31, the route search request / route search response transmission / reception unit 32 creates a route search request or route search response and sends it to the IP processing unit 22 to request transmission. Further, the route search request / route search response transmission / reception unit 32 sends the route search request or the route search response sent from the IP processing unit 22 to the ad hoc routing protocol processing unit 31.

  The route search request / route search response transmission / reception unit 32 obtains a transmission wait time from the transmission wait time processing unit 33 and receives a reception signal from the reception signal level processing unit 34 when creating a route search request or a route search response. Get the level. Further, the route search request / route search response transmission / reception unit 32, when the own wireless communication device functions as a data transmission source, sets the transmission waiting time and the received signal level included in the received route search request or route search response, The data is sent to the network traffic judgment unit 35 and the network line quality judgment unit 36, respectively.

  The transmission waiting time processing unit 33 receives the transmission waiting time from the transmission waiting time measuring unit 11 of the wireless transmission / reception unit 2 via the wireless transmission / reception unit driver 21 and holds it inside. Further, the transmission waiting time processing unit 33 sends the held transmission waiting time to the route search request / route search response transmission / reception unit 32 in response to a request from the route search request / route search response transmission / reception unit 32.

  The reception signal level processing unit 34 receives data representing the reception signal level from the reception signal level measurement unit 12 of the wireless transmission / reception unit 2 via the wireless transmission / reception unit driver 21 and holds the data therein. Also, the received signal level processing unit 34 sends the received received signal level to the route search request / route search response transmission / reception unit 32 in response to a request from the route search request / route search response transmission / reception unit 32.

  The network traffic determination unit 35 sets the upper limit of the transmission data amount per unit time according to the transmission waiting time received from the route search request / route search response transmission / reception unit 32 when the own wireless communication device functions as a data transmission source. Then, it is determined according to the correspondence table 35 a held inside and sent to the upper layer processing unit 24.

  When the wireless communication apparatus functions as a data transmission source, the network line quality determination unit 36 internally retains a transmission data size corresponding to the received signal level received from the route search request / route search response transmission / reception unit 32. And is sent to the wireless transmission / reception unit 2 via the wireless transmission / reception unit driver 21 and set as a parameter. Here, the transmission data size is the amount of data included in one packet, in other words, the packet length. In the case of a wireless LAN, the transmission data size can be considered as a frame length.

  Next, the operation of the wireless communication system according to the first embodiment of the present invention configured as described above will be described with reference to the flowchart shown in FIG. 4, focusing on the processing executed by the route search request / route search response transmission / reception unit 32. The description will be given with reference.

  Each wireless communication device that relays a route search request or a route search response first receives the route search request or the route response request (step S1). Next, it is checked whether or not the “transmission waiting time” indicating the communication traffic amount included in the received route search request or route search response is smaller than the “transmission waiting time” held in the own wireless communication device (step S2). ). That is, the route search request / route search response transmission / reception unit 32 has a transmission waiting time included in the route response request or the route search response received from the IP processing unit 22 smaller than the transmission waiting time received from the transmission waiting time processing unit 33. Find out if.

  If it is determined in step S2 that the “transmission waiting time” included in the received route search request or route search response is smaller than the “transmission waiting time” held in the own wireless communication device, the own wireless communication device Is stored in the route search request or route search response (step S3).

  On the other hand, if it is determined in step S2 that the “transmission waiting time” included in the received route search request or route search response is not smaller than the “transmission waiting time” held in the own wireless communication device, The process of S3 is skipped.

  Next, it is checked whether or not the “reception signal level” representing the channel quality included in the received route search request or route search response is greater than the “reception signal level” held in the own wireless communication device (step S4). . That is, the route search request / route search response transmission / reception unit 32 has a received signal level included in the route search request or the route response request received from the IP processing unit 22 greater than the received signal level received from the received signal level processing unit 34. Find out if.

  If it is determined in step S4 that the “reception signal level” included in the received route search request or route search response is greater than the “reception signal level” held in the own wireless communication device, the own wireless communication device Is stored in the route search request or route search response (step S5). On the other hand, if it is determined in step S4 that the received signal level included in the received route search request or route search response is not greater than the “received signal level” held in the own wireless communication device, the process proceeds to step S5. Processing is skipped.

  Next, a route search request or a route search response is transmitted (step S6). That is, the route search request / route search response transmission / reception unit 32 sends the route search request or the route search response with the updated transmission waiting time or received signal level to the IP processing unit 22 and transmits it.

  The data transmission destination wireless communication device transmits a route search response as a response to the route search request. The communication traffic amount (transmission waiting time) and the line quality (received signal level) are also set by the above-described method. Is done.

  Next, the operation of the wireless communication system constructed by the wireless communication apparatus configured as described above will be described with reference to FIGS. This wireless communication system includes a wireless communication device A that is a data transmission source, a wireless communication device B and a wireless communication device C that are relay points, and a wireless communication device D that is a data transmission destination. To do.

  First, transmission of a route search request in ad hoc routing will be described with reference to FIG. First, when data to be transmitted is generated in the wireless communication apparatus A, the wireless communication apparatus A becomes a data transmission source and broadcasts a route search request. In this case, the transmission waiting time held by the wireless communication apparatus A is “10 μs”, and the received signal level is “undecided (−)”. This broadcast transmission from the wireless communication device A is received by the wireless communication device B and the wireless communication device C that are within the reach of radio waves.

  When the wireless communication device B that has received the route search request broadcasted from the wireless communication device A determines that the route search request is not addressed to itself, the wireless communication device B holds the transmission waiting time “8 μs” and the received signal level “ −72 dBm ”is compared with the transmission waiting time“ 10 μs ”and the received signal level“ undecided (−) ”included in the received route search request, respectively, and the worse transmission waiting time“ 10 μs ”and the received signal level“ − ”are compared. A route search request including “72 dBm” is generated and broadcast.

  The broadcast transmission from the wireless communication device B is received by the wireless communication device A, the wireless communication device C, and the wireless communication device D that are within the reach of radio waves. In this case, since the wireless communication device A is a route search request broadcasted by itself, the wireless communication device A ignores the route search request broadcasted from the wireless communication device B. The wireless communication device C recognizes that the route search request broadcast from the wireless communication device B is the same as the route search request broadcast from the wireless communication device A, and is broadcast from the wireless communication device B. Ignore the route search request.

  On the other hand, the wireless communication device C that has received the route search request broadcast from the wireless communication device A receives the transmission waiting time “12 μs” and the received signal level “−68 dBm” that it has received, and the received route search request. Is compared with the transmission waiting time “10 μs” and the received signal level “undecided (−)”, and a route search request including the transmission waiting time “12 μs” and the received signal level “−68 dBm” is generated and broadcast transmission is performed. To do.

  The broadcast transmission from the wireless communication device C is received by the wireless communication device A, the wireless communication device B, and the wireless communication device D that are within the reach of radio waves. In this case, the wireless communication device A ignores the route search request broadcasted from the wireless communication device C because it is a route search request broadcasted by itself. The wireless communication device B recognizes that the route search request broadcast from the wireless communication device C is the same as the route search request broadcast from the wireless communication device A, and is broadcast from the wireless communication device C. Ignore the route search request.

  The wireless communication device D processes the previously received route search request among the route search request broadcasted from the wireless communication device B and the route search request broadcasted from the wireless communication device C. Assuming that the wireless communication device D receives the route search request broadcasted from the wireless communication device C first, the wireless communication device D receives the route search request including the transmission waiting time “12 μs” and the received signal level “−68 dBm”. To do.

  Next, transmission of a route search response in ad hoc routing will be described with reference to FIG. When the wireless communication device D receives the route search request broadcast from the wireless communication device B and includes the transmission waiting time “12 μs” and the received signal level “−68 dBm”, the wireless communication device D responds to the route search request. The transmission waiting time “14 μs” and the received signal level “−74 dBm” held are compared with the transmission waiting time “10 μs” and the received signal level “−72 dBm” included in the received route search request, respectively. A route search response including the transmission waiting time “14 μs” and the worse received signal level “−74 dBm” is generated, and the route search request is transmitted to the wireless communication apparatus B that has transmitted the broadcast.

  The wireless communication device B that has received the route search response from the wireless communication device D waits for transmission included in the received route search request and the transmission waiting time “8 μs” and the received signal level “−76 dBm” held by itself. The time “14 μs” and the received signal level “−74 dBm” are respectively compared, and a route search response including the worse transmission waiting time “14 μs” and the worse received signal level “−76 dBm” is generated. The route search request is transmitted to the wireless communication apparatus A that has transmitted the broadcast.

  The ad hoc routing processing unit 23 of the wireless communication device A that has received the route search response from the wireless communication device B acquires the transmission data amount corresponding to the transmission waiting time of 14 μs from the correspondence table 35 a in the network traffic determination unit 35, The data is sent to the layer processing unit 24. In addition, the ad hoc routing processing unit 23 of the wireless communication apparatus A acquires the transmission data size corresponding to the reception signal level of −76 dBm from the correspondence table 36 a in the network line quality determination unit 36, and wirelessly transmits via the wireless transmission / reception unit driver 21. Set in the transceiver 2.

  Thereafter, data transmission from the wireless communication device A to the wireless communication device D is performed according to the transmission data amount and the transmission data size determined as described above. That is, when the maximum communication traffic amount (transmission waiting time) and the worst line quality (received signal level) are determined, the wireless communication device A that is the data transmission source determines the maximum communication traffic amount (transmission waiting time). , The upper limit of the transmission data amount per unit time is determined, and data is transmitted according to the determined transmission data amount.

  Further, the wireless communication apparatus A determines the upper limit of the transmission data size with reference to the received worst line quality (received signal level), and for the data exceeding the determined upper limit of the transmission data size, the wireless transmission / reception unit 2 Divide (fragment) with and send.

  As described above, according to the wireless communication system according to the first embodiment of the present invention, by setting the upper limit of the transmission data amount per unit time according to the maximum communication traffic amount (transmission waiting time), Communication load in the wireless communication system can be suppressed. If the communication load becomes excessive, collisions and transmission failures (retry outs) occur frequently in the wireless LAN and the communication efficiency of the entire wireless communication system decreases. However, by setting an upper limit on the amount of transmission data, the entire wireless communication system As a result, communication efficiency can be improved.

  Further, by setting the upper limit of the transmission data size according to the worst line quality (received signal level), it is possible to reduce the decrease in communication efficiency. When the line quality is low, the communication efficiency as a whole can be improved by reducing the transmission data size.

  The present invention is applicable to a wireless ad hoc network system using a wireless LAN in which the network topology changes with time.

It is a block diagram which shows the structure of the radio | wireless communication apparatus used with the radio | wireless communications system which concerns on Example 1 of this invention. FIG. 2 is a block diagram illustrating a detailed configuration of an ad hoc routing processing unit of the wireless communication apparatus illustrated in FIG. 1. It is a figure which shows the transmission / reception data format of the data transmitted / received with the radio | wireless communication apparatus used with the radio | wireless communications system which concerns on Example 1 of this invention. It is a flowchart which shows operation | movement of the radio | wireless communication apparatus used with the radio | wireless communications system which concerns on Example 1 of this invention. It is a figure for demonstrating operation | movement of the route search request | requirement in the radio | wireless communications system which concerns on Example 1 of this invention. It is a figure for demonstrating the operation | movement of the route search response in the radio | wireless communications system which concerns on Example 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2 Wireless transmission / reception part 3 Communication processing part 11 Transmission waiting time measurement part 12 Received signal level measurement part 21 Wireless transmission / reception part driver 22 IP processing part 23 Ad hoc routing processing part 24 Upper layer processing part 31 Ad hoc routing protocol processing part 32 Path search Request / route search response transmission / reception unit 33 Transmission waiting time processing unit 34 Reception signal level processing unit 35 Network traffic determination unit 35a Correspondence table 36 Network line quality determination unit 36a Correspondence table

Claims (8)

A wireless communication system composed of a plurality of wireless communication devices,
Each of the plurality of wireless communication devices is
A transmission latency measurement unit that measures the transmission latency, and
When a route search request or route search response for route establishment received from another wireless communication device is not addressed to itself, a transmission waiting time included in the route search request or route search response is measured by the transmission wait time measuring unit. The transmission waiting time included in the received route search request or route search response is replaced with the transmission waiting time measured by the transmission waiting time measurement unit, and broadcasted to the outside, A communication processing unit that transmits data adjusted to have a transmission data amount corresponding to a transmission waiting time included in the route search response when the route search response received from another wireless communication device is addressed to itself; ,
A wireless communication system comprising: A wireless communication system composed of a plurality of wireless communication devices,
Each of the plurality of wireless communication devices is
A received signal level measuring unit for measuring the received signal level;
When a route search request or route search response for establishing a route received from another wireless communication device is not addressed to itself, the received signal level included in the route search request or route search response is measured by the received signal level measuring unit. If the received signal level is greater than the received signal level, the received signal level included in the received route search request or route search response is replaced with the received signal level measured by the received signal level measuring unit, and broadcasted to the outside. A communication processing unit that transmits data adjusted to have a transmission data size corresponding to a received signal level included in the route search response when a route search response received from another wireless communication device is addressed to the device; ,
A wireless communication system comprising: Each of the plurality of wireless communication devices further includes:
A reception signal level measurement unit for measuring the reception signal level is provided.
The communication processing unit further includes a reception signal level included in the route search request or the route search response when the route search request or route search response for route establishment received from another wireless communication device is not addressed to itself. If the received signal level is larger than the received signal level measured by the received signal level measuring unit, the received signal level included in the received route search request or route search response is the received signal level measured by the received signal level measuring unit. When the route search response received from other wireless communication devices is addressed to itself, the transmission data size is adjusted so as to correspond to the received signal level included in the route search response. The wireless communication system according to claim 1, wherein data is transmitted. The wireless communication system according to any one of claims 1 to 3, wherein the plurality of wireless communication devices are connected by a wireless ad hoc network. A wireless communication device used in a wireless communication system composed of a plurality of wireless communication devices,
A transmission latency measurement unit that measures the transmission latency;
When a route search request or route search response for route establishment received from another wireless communication device is not addressed to itself, the transmission wait time included in the route search request or route search response is measured by the transmission wait time measurement unit. The transmission waiting time included in the received route search request or route search response is replaced with the transmission waiting time measured by the transmission waiting time measurement unit, and broadcast to the outside, A communication processing unit that transmits data adjusted to have a transmission data amount corresponding to a transmission waiting time included in the route search response when the route search response received from another wireless communication device is addressed to the device; ,
A wireless communication apparatus comprising: A wireless communication device used in a wireless communication system composed of a plurality of wireless communication devices,
A received signal level measuring unit for measuring the received signal level;
When a route search request or route search response for route establishment received from another wireless communication device is not addressed to itself, the received signal level included in the route search request or route search response is measured by the received signal level measurement unit. If the received signal level is greater than the received signal level, the received signal level included in the received route search request or route search response is replaced with the received signal level measured by the received signal level measurement unit, and broadcasted to the outside. A communication processing unit that transmits data adjusted to have a transmission data size corresponding to the received signal level included in the route search response when the route search response received from another wireless communication device is addressed to itself; ,
A wireless communication apparatus comprising: Furthermore, a reception signal level measurement unit for measuring the reception signal level is provided,
The communication processing unit further includes a reception signal level included in the route search request or the route search response when the route search request or route search response for route establishment received from another wireless communication device is not addressed to itself. If the received signal level is larger than the received signal level measured by the received signal level measuring unit, the received signal level included in the received route search request or route search response is the received signal level measured by the received signal level measuring unit. When the route search response received from other wireless communication devices is addressed to itself, the transmission data size is adjusted so as to correspond to the received signal level included in the route search response. 6. The wireless communication apparatus according to claim 5, wherein the wireless communication apparatus transmits data.   The wireless communication apparatus according to claim 5, wherein the wireless communication apparatus is connected to the other wireless communication apparatus through a wireless ad hoc network.

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