JP5682487B2 - Wireless communication apparatus and communication route selection method - Google Patents

Description

  The present invention relates to a wireless communication apparatus and a communication route selection method. The present invention can be suitably applied to, for example, a wireless communication device that performs multi-hop communication and a communication route selection method when performing routing for determining a communication route of multi-hop communication.

  When performing multi-hop communication in wireless communication, each wireless communication device determines a communication route for multi-hop communication, and then performs multi-hop communication via the communication route. When determining a communication route for multi-hop communication, a route with the minimum number of relay devices is selected as a route from a transmission source wireless communication device to a destination wireless communication device, or received field strength (RSSI: Received) The communication route is determined based on route selection criteria such as obtaining the communication distance between each relay device from the signal strength indication and selecting the route having the shortest total communication distance.

  For example, when wireless communication devices 15-1 to 15-11 are arranged as shown in FIG. 15 and the wireless communication device 15-1 communicates with the wireless communication device 15-2, a relay device that is a conventional route selection criterion When the communication route is determined based on the criterion of minimizing the number, the route passing through the wireless communication device 15-3 and the wireless communication device 15-4 is selected as shown in FIG.

  In addition, the wireless communication device includes a directional antenna, measures reception quality in a plurality of directional directions, determines the state of the surrounding wireless environment based on the reception quality, and performs routing for multihop wireless communication. For example, it is known from Patent Document 1 below.

Japanese Patent Laid-Open No. 2003-258811

  The above-described conventional route selection method can relay a plurality of communication routes to a specific wireless communication device even if the route selection is appropriate in terms of minimizing the number of relay devices or minimizing the total communication distance. In some cases, the route may not be an optimal route in terms of congestion and reduced throughput.

  For example, when the communication between the wireless communication device 15-8 and the wireless communication device 15-11 is relayed between the wireless communication device 15-3 and the wireless communication device 15-4 in the arrangement example of FIG. When communication between the device 15-1 and the wireless communication device 15-2 is relayed between the wireless communication device 15-3 and the wireless communication device 15-4, a problem of congestion occurs.

  Therefore, as shown in FIG. 17, the communication between the wireless communication device 15-1 and the wireless communication device 15-2 is a route via the wireless communication device 15-5, the wireless communication device 15-6, and the wireless communication device 15-7. However, the number of relay devices increases, but a decrease in transmission rate due to congestion can be suppressed.

  In addition, the conventional method of determining the status of the surrounding wireless environment and routing multi-hop wireless communication once the communication route is determined, the surrounding wireless environment status changes and more optimal communication is possible. Even if a new route is generated, the communication route is not changed following the change.

  The present invention selects a communication route by avoiding a wireless communication device that is already congested by relaying a large number of communications, etc., and immediately selects an optimal communication route in response to changes in the surrounding wireless environment. It is an object to provide a wireless communication apparatus and a communication route selection method that can be changed to

A wireless communication apparatus according to an embodiment for solving the above-described problems is a wireless communication apparatus having a multi-hop communication function and including a plurality of antennas having different directivity directions of transmission / reception waves. A space utilization rate calculating means for measuring and comparing with a predetermined intensity threshold value, and calculating a ratio of the observation time or the number of sampling times of the received electric field intensity exceeding the intensity threshold value as a space utilization rate for each pointing direction in the wireless space; , Comparing each space utilization rate for each orientation direction with a predetermined utilization threshold value, and when there is a pointing direction with a space utilization rate less than or equal to at least one utilization factor threshold, the space utilization less than the utilization threshold value one of the rate of orientation, selected as the search direction of the communication route, when the orientation of the space utilization ratio which follows the utilization threshold has not been discovered one more the utilization threshold And compare each space utilization rate for each directivity direction with a higher utilization threshold value, and select a directivity direction with a space utilization factor equal to or lower than the higher utilization threshold value as a search direction for the communication route. Search direction selection means to correct, means for transmitting a routing signal for determining a communication route of multi-hop communication in the directivity direction selected by the search direction selection means, and each directivity direction after the start of multi-hop communication Means for measuring each received electric field strength to calculate each space utilization factor, and based on the space utilization factor, performing a search operation for selecting a communication route search direction by the search direction selection unit. It is.

Another aspect of the wireless communication apparatus is a wireless communication apparatus having a multi-hop communication function and having a plurality of antennas having different directivity directions of transmission and reception waves, and measuring each received electric field strength for each directivity direction. Then, compared with a predetermined intensity threshold, a space utilization rate calculating means for calculating the ratio of the observation time or the number of sampling times of the received electric field intensity exceeding the intensity threshold as a space utilization rate for each pointing direction in the wireless space, Each space utilization rate for each directivity direction is compared with a predetermined utilization threshold value, and when there is a directivity direction with a space utilization factor equal to or less than at least one utilization factor threshold, the space utilization factor equal to or less than the utilization threshold value Is selected as the search direction of the communication route, and when no directivity direction of the space utilization rate that is equal to or lower than the utilization threshold value is found, the intensity threshold value is set to a higher value. In the space utilization rate calculating means, the higher intensity threshold value and the received electric field strength are compared to calculate a space utilization rate for each directivity direction in the wireless space, and the utilization rate is calculated using the space utilization rate. A search direction selection means for reselecting a directivity direction below a rate threshold as a search direction for the communication route; and a routing signal for determining a communication route for multi-hop communication in the directivity direction selected by the search direction selection means. And after the start of multi-hop communication, each received electric field strength for each direction is measured to calculate each space utilization rate, and communication by the search direction selection unit is performed based on the space utilization rate. And a means for performing a route search direction selection operation.

A communication route selection method that solves the above-described problem is a communication route selection method for determining a communication route of a wireless communication device that performs multi-hop communication, and includes a plurality of different directivity directions provided in the wireless communication device. Each received electric field strength for each directivity direction received by the antenna is measured and compared with a predetermined strength threshold, and the ratio of the observation time or the number of sampling times of the received electric field strength exceeding the strength threshold is set for each directivity in the radio space. When there is a spatial utilization factor calculating step for calculating the spatial utilization factor for each direction and a directivity direction of the spatial utilization factor equal to or less than the utilization threshold value of at least one , the directivity direction of the spatial utilization factor equal to or less than the utilization threshold value One of them is selected as the search direction of the communication route, and when no directivity direction of the space utilization rate that is less than or equal to the utilization threshold value is found, the utilization threshold value is referred to. Set a high value, compare each space utilization rate for each orientation direction with a higher utilization threshold value, and select a directivity direction with a space utilization rate lower than the higher utilization threshold value as a search direction for the communication route. If there is a pointing direction with a space utilization factor that is less than or equal to at least one utilization factor threshold, one of the directivity directions with a space utilization factor that is less than or equal to the utilization threshold value is determined as the search direction for the communication route. And when no directivity direction of the space utilization factor that is equal to or less than the utilization threshold value is found, the intensity threshold value is set to a higher value, and the space utilization factor calculating unit determines the higher intensity threshold value. And the received electric field strength to calculate the space utilization rate for each directivity direction in the wireless space, and using the space utilization rate, select a directivity direction that is equal to or less than the utilization threshold value as a search direction for the communication route. Shi And to search direction selection step, the oriented direction selected in the search direction selection step, sending a routing signal from the antenna to determine the communication route of a multi-hop communication, after the start of the multi-hop communication, the respective orientation And measuring each other received electric field strength to calculate each space utilization rate, and performing a search direction selection operation of a communication route by the search direction selection means based on the space utilization rate.

  Multi-hop communication routing can be performed while avoiding a direction with a high space utilization rate, and it is possible to avoid a concentration of communication in a specific wireless communication device or wireless space. For this reason, many other communications can be relayed, and a communication route can be selected by avoiding radio relay devices and radio spaces where signals frequently fly, preventing a decrease in throughput and a decrease in transmission speed due to congestion. Is possible.

  Even after the communication route is determined and communication is started, the status of the surrounding wireless environment is monitored, the communication route with less congestion is searched for the change in the surrounding wireless environment status, and the optimum communication route It becomes possible to change immediately.

It is a figure which shows the example of an operation | movement flow of a radio | wireless communication apparatus. It is a figure which shows an example of the directivity direction of each antenna. It is a figure which shows an example of the time change of the received electric field strength according to each directional direction. It is explanatory drawing of the specific method for calculating a space utilization factor. It is a figure which shows the structural example of the packet of a routing signal. It is a figure which shows the structural example of the radio | wireless communication apparatus of a 1st Example. It is a figure which shows the example of an operation | movement flow which changes a utilization rate threshold value and performs route search. It is a figure which shows the example of an operation | movement flow which changes an intensity | strength threshold value and performs route search. It is a figure which shows the example of an operation | movement flow which performs route search, without changing a threshold value. It is a figure which shows the example of an operation | movement flow with respect to failure in search of a communication route. It is a figure which shows the structural example of the radio | wireless communication apparatus of 2nd Example. It is a figure which shows the example of an operation | movement flow which selects a route search direction by comparing space utilization. It is a figure which shows the structural example of the packet which identifies the antenna which transmitted the routing signal. It is a figure which shows the structural example which provided the antenna for communication separately from the antenna used for routing. It is a figure which shows the example of arrangement | positioning of a radio | wireless communication apparatus. It is a figure which shows the example of the communication route by the route selection reference | standard with the minimum number of relay apparatuses. It is a figure which shows the example of the communication route which congestion is hard to generate | occur | produce.

  The disclosed wireless communication apparatus includes a plurality of directional antennas, and measures the received electric field strength in each directional direction. Then, a space utilization rate serving as an index indicating the congestion state in each directivity direction is obtained from the time ratio at which the received electric field intensity exceeds the threshold value. And a routing signal is transmitted with respect to the direction where this space utilization rate is low, and a communication route is determined.

  In addition, even after starting communication on the communication route once determined, the space utilization rate is calculated based on the received electric field strength of each antenna, and the routing signal is transmitted in the directivity direction where the space utilization rate has decreased. The communication route that is already communicating and the communication route that is already communicating are compared, and a route with a lower space utilization rate is selected.

  A wireless relay device that exists in a pointing direction with a high space utilization rate relays many other communications, and throughput decreases when the wireless relay device is routed through the wireless relay device. Alternatively, since radio signals frequently fly in a pointing direction with a high space utilization rate, congestion is likely to occur. Therefore, by performing routing while avoiding a directivity direction having a high space utilization rate, it is possible to avoid a concentration of communication in a specific wireless communication device or wireless space.

  FIG. 1 shows an example of an operation flow of the disclosed wireless communication apparatus. When a request for data transmission is generated in the wireless communication device (1-1), the received electric field strength of the wireless signal received by each antenna is measured (1-2). Then, the space utilization factor of the radio space in the directivity direction of each antenna is calculated from the received electric field strength of each antenna (1-3).

  Based on the space utilization rate, a pointing direction having a low absolute value or relative value of the space utilization rate is selected as a communication route search direction for multi-hop communication (1-4). Then, a routing signal for routing multihop communication is transmitted in the search direction, a search for a communication route is started (1-5), and a communication route for multihop communication is determined (1-6). .

  Data transmission of multi-hop communication is started using the determined communication route (1-7), and the wireless communication apparatus monitors the reception electric field strength of each antenna even during the communication of the multi-hop communication, and based on the reception electric field strength. The space utilization factor for each pointing direction is calculated (1-8). When the space utilization rate varies, a direction with a low space utilization rate is selected as the communication route search direction (1-4), and the routing signal is transmitted again by the same process. The communication route is searched (1-5), and the communication route for multi-hop communication is changed (1-6).

  When determining a communication route or changing a communication route, if a plurality of communication routes are discovered by transmitting routing signals in a plurality of route search directions, the space utilization rate of each discovered communication route Are compared with each other, and a communication route with a lower space utilization rate is selected.

  An example of the directivity direction of each antenna in the embodiment of this wireless communication apparatus is shown in FIG. FIG. 2A shows an example of the directivity pattern of the directional antenna. The wireless communication apparatus 100 of this embodiment includes four directional antennas having a directional pattern as shown in FIG. 2A, and the four directional antennas are different as shown in FIG. 2B. It is assumed that they are arranged so as to face the first to fourth directing directions 2-1, 2-2, 2-3, 2-4.

  A radio signal arriving at the radio communication device 100 is received by each directional antenna, and the radio communication device 100 measures the received electric field strength of each directional antenna and based on the received electric field strength of each antenna in the directivity direction. The space utilization rate of the wireless space is calculated. The wireless communication device 100 determines the congestion status of the wireless space based on the space utilization rate.

  FIG. 3 shows an example of a temporal change in received electric field strength for each antenna directivity direction, where (a) is a first directivity direction, (b) is a second directivity direction, and (c) is a third directivity direction. The directivity direction, (d) shows an example of the received electric field strength (RSSI) in the fourth directivity direction. In the example of FIG. 3, the time ratio (that is, space utilization rate) at which the received electric field strength higher than the strength threshold indicated by the broken line is observed is the largest in the first pointing direction, and the wireless space in the first pointing direction is the largest. It is determined that it is crowded.

  A specific method for calculating the space utilization rate will be described with reference to FIG. FIG. 4A shows an example in which the space utilization rate is calculated based on the ratio of time during which the received electric field strength equal to or higher than a predetermined strength threshold is observed. That is, a predetermined observation period T is determined in advance, and the observation times t1, t2, and t3 during which the received electric field intensity equal to or greater than the intensity threshold is observed within the predetermined observation period T, and the intensity threshold for the observation period T is measured. The ratio of the total time of the observation times t1, t2, and t3 of the received electric field intensity is calculated as the space utilization rate. For example, when the received electric field intensity is observed with a predetermined observation period T of 20 seconds, and the total of the observation times t1, t2, and t3 exceeding the intensity threshold is 15 seconds, the space utilization rate is 75% (= 15 ÷ 20).

  FIG. 4B shows an example in which the space utilization rate is calculated based on the ratio of the number of sampling measurements at which a received electric field strength equal to or greater than a predetermined strength threshold is observed. That is, a predetermined number of sampling measurement times for measuring the received electric field strength is determined in advance, and the ratio of the sampling measurement number at which the received electric field strength equal to or higher than the intensity threshold is observed to the total sampling measurement number is defined as the space utilization rate. calculate. For example, when the number of sampling measurements exceeding the intensity threshold is 14 out of 20 total sampling measurements, the space utilization rate is calculated as 70% (= 14 ÷ 20).

  FIG. 4C shows an example in which the space utilization rate is calculated based on the ratio of the number of sampling measurements in which the received electric field strength equal to or greater than the strength threshold is observed within the predetermined observation period T. That is, a predetermined observation period T is determined in advance, and the ratio of the number of sampling measurements in which the received electric field intensity equal to or greater than the intensity threshold is observed within the predetermined observation period T to the total number of sampling measurements within the observation period T Calculate as usage rate. For example, it is assumed that the predetermined observation period T is 20 seconds and the total number of sampling measurements during that period is 13. In the observation period T, the number of sampling measurements in which the received electric field strength exceeds the intensity threshold is 9 times. In this case, the space utilization rate is calculated as 69% (= 9 ÷ 13).

  The directivity direction in which the routing signal is transmitted based on the space utilization factor for each directivity direction by calculating the spatial utilization factor for each directivity direction based on the received electric field strength in the directivity direction of each antenna by any of the above-described methods. And a routing signal is transmitted from the antenna in the directivity direction. The routing signal has a packet structure as shown in FIG. 5, for example, and includes a preamble 5-1, a synchronization word 5-2, a packet length 5-3, a source address 5-4, a destination address 5-5, and a hop count 5. -6, data portion 5-7 is included.

  The communication route is determined using, for example, an AODV (Ad hoc On-Demand Distance Vector) protocol. The wireless communication device that has received the routing signal checks whether or not its own address matches the destination address in the routing signal, and if it matches, sends a route determination signal back to the transmission source.

  If it is different from the destination address, refer to the routing table held in the device, check whether the destination address recorded in the routing table matches the destination address in the routing signal, and if they match, A route determination signal is sent back to the transmission source. The route determination signal is sent to the transmission source by reversing the route up to that point. When the destination address does not exist in the route table, the routing signal is transmitted to another wireless communication device. In the routing table, a partner to be transmitted next corresponding to the destination is recorded.

  To prevent the routing signal from being relayed forever, the number of hops is recorded in the packet, and the number of hops is incremented by 1 each time the routing signal is relayed. In this case, the relay of the routing signal is stopped so that the routing signal is not relayed any more.

  The source communication device cannot know the route to the destination, but communicates with the relaying communication device as a partner based on the route table. The same operation is repeatedly performed in the communication device as the relay device, and the routing signal finally reaches the destination communication device.

  FIG. 6 shows a configuration example of the wireless communication apparatus according to the first embodiment. The wireless communication apparatus 100 includes a received electric field strength measurement unit 101, a strength determination unit 102, and a space utilization rate calculation unit 103 for each antenna 120 having directivity. In addition, the wireless communication device 100 includes a space utilization rate recording unit 104, a transmission direction determination unit 105, a routing signal transmission antenna control unit 106, a routing signal creation unit 107, a utilization rate threshold setting unit 108, an intensity threshold setting unit 109, and an antenna used. The determination part 110, the antenna control part 111, and the communication part 112 are provided.

  The received electric field strength measuring unit 101 measures the received electric field strength of each antenna 120 and sends the measured value to the strength determining unit 102. The strength determination unit 102 compares the measured received electric field strength value with the strength threshold set in the strength threshold setting unit 109. If the received electric field strength exceeds the strength threshold, the wireless space is another wireless communication device. And the determination result is sent to the space utilization rate calculation unit 103.

  The space utilization rate calculation unit 103 calculates the space utilization rate by collecting the determination results for a predetermined observation period or a predetermined number of sampling measurements sent from the intensity determination unit 102, and records the space utilization rate. To the unit 104. The space utilization rate recording unit 104 stores the space utilization rate calculated by each space utilization rate calculation unit 103 for each directivity direction of each antenna.

  The transmission direction determination unit 105 compares the space usage rate for each direction stored in the space usage rate recording unit 104 with the usage rate threshold set in the usage rate threshold setting unit 108, and each space usage rate is used. It is determined whether or not it falls below the rate threshold. Based on the determination result, the transmission direction determination unit 105 selects an antenna having a directivity direction in which the space utilization rate is lower than the utilization threshold value.

  The transmission direction determination unit 105 notifies the routing signal transmission antenna control unit 106 of the identification information of the selected antenna. The routing signal transmission antenna control unit 106 performs control so that the routing signal generated by the routing signal generation unit 107 is transmitted in the direction of the antenna selected by the transmission direction determination unit 105.

  In addition, in the method of comparing the space utilization rate for each orientation and the utilization threshold, and selecting the orientation direction below the utilization threshold, if the space utilization in all orientation directions exceeds the utilization threshold, routing It is not possible to select a directivity direction for transmitting a signal.

  In such a case, the transmission direction determination unit 105 changes the usage rate threshold set in the usage rate threshold setting unit 108 to a higher value, and changes the space usage rate for each direction of use after the change. It is compared with the rate threshold value to determine whether each space usage rate is below the usage rate threshold value. Based on the determination result, it is possible to reselect an antenna having a directivity direction in which the space utilization rate is lower than the changed utilization threshold value.

  An example of an operation flow for performing route search by changing the above utilization threshold is shown in FIG. In the example of the operation flow in FIG. 7, operations 1-1 to 1-3 and 1-5 to 1-8 are the same as the operation flow in FIG. In the example of the operation flow in FIG. 7, after calculating the space utilization rate for each antenna directivity direction according to the operation flow 1-3, the space utilization rate for each directivity direction is compared with the utilization threshold value. The antenna directivity direction with a space utilization factor lower than is selected as the route search direction (7-1).

  After performing the operation 7-1, it is determined whether one or more route search directions are selected (7-2). When one or more route search directions are selected, a route search is started in the same manner as the operation flow of FIG. 1 (1-5), and thereafter, an operation flow similar to the operation flow of FIG. On the other hand, when no route search direction is selected, the utilization threshold is changed to a higher value (7-3), and the flow returns to the operation flow 7-1 again to change the space utilization for each direction. Compared with the later utilization threshold, the antenna in the directional direction with a spatial utilization lower than the utilization threshold is selected again.

  Moreover, it can replace with the structure which changes the above-mentioned utilization factor threshold value to a high value, and can be set as the structure which changes the intensity | strength threshold value with respect to the received electric field strength used for the utilization determination of radio | wireless space high. In the case of such a configuration, the transmission direction determination unit 105 changes the intensity threshold set in the intensity threshold setting unit 109 to a higher value.

  Then, the strength determination unit 102 compares the measured received electric field strength value with the strength threshold value that has been changed to a higher value, and if the received electric field strength exceeds the strength threshold value, the wireless space is determined by another wireless communication device. In order to determine that the space is being used, the space utilization rate calculation unit 103 calculates the space utilization rate to a lower value than when the intensity threshold is low. As a result, it is possible to reduce the probability that the space utilization rate in all the directional directions exceeds the utilization threshold value.

  FIG. 8 shows an example of an operation flow of a configuration in which the intensity threshold value is changed to be high. In this operation flow example, instead of the operation flow 7-3 (operation of changing the utilization threshold value to a higher value) in the operation flow of FIG. 7, the received electric field strength for determining whether or not the wireless space is used is determined. The operation is changed to the operation (8-1) for changing the intensity threshold to a higher value. After changing the strength threshold value to a higher value (8-1), the operation (1-3) of calculating the space utilization rate of the radio space in the direction of each antenna is performed from the received electric field strength of each antenna. The operation similar to the operation described with reference to FIG.

  As yet another modified example, as shown in the operation flow example shown in FIG. 9, as a result of determining whether or not one or more route search directions have been selected (7-2), the space usage rate becomes equal to or lower than a predetermined usage rate. If there is no pointing direction and no route search direction is selected, the operation (1-2) of simply measuring the received electric field strength with each antenna is performed again, and the route search direction selection operation is repeated. Can do. This is because the space utilization situation in the radio space is not constant, and the received electric field strength of each antenna may fluctuate. Therefore, by re-measuring the received electric field strength of each antenna, one or more route search directions are selected. This is because there is a possibility.

  Even if a direction with low space utilization is selected as a route search direction and a routing signal is transmitted in the route search direction, there is no wireless communication device serving as a relay device in the route search direction. May fail.

  As a countermeasure against such a case, for example, as in the operation flow shown in FIG. 10, it is determined whether or not a communication route has been found (10-1). The value is changed to a higher value (10-2), and the route search direction is selected again (7-1). By doing so, it is possible to increase the route search direction, increase the probability that a route in which a wireless communication device as a relay device exists is selected, and increase the success rate of route search.

  Instead of the transmission direction determination unit 105 in the configuration example of the first embodiment illustrated in FIG. 6 described above, a configuration including a transmission direction comparison unit 113 as illustrated in FIG. The transmission direction determination unit 105 compares the space utilization rate for each directivity direction with a predetermined utilization rate threshold value, and selects a directivity direction in which the absolute value of the space utilization rate is lower than the utilization rate threshold value. The direction comparison unit 113 compares the space utilization rates for each directivity direction with each other, and selects a directivity direction with a relatively lower space utilization rate as a search direction for the communication route.

  FIG. 12 shows an example of an operation flow of an embodiment for selecting a route search direction by comparing space utilization rates with each other. In this embodiment, when a request for data transmission occurs (1-1), the received electric field strength of a radio signal received by each antenna is measured (1-2). Then, the space utilization factor of the radio space in the directivity direction of each antenna is calculated from the received electric field strength of each antenna (1-3).

  Based on the above space utilization rates, the space utilization rates for each directivity direction are compared with each other, and the directivity direction having a relatively lower space utilization rate is selected as the search direction for the communication route ( 12-1). Then, a routing signal for routing multihop communication is transmitted in the search direction, a search for a communication route is started (1-5), and a communication route for multihop communication is determined (1-6). .

  Multi-hop communication data transmission is started using the determined communication route (1-7). Even during the multi-hop communication, the wireless communication apparatus monitors the received electric field strength of each antenna and calculates the space utilization rate for each directional direction based on the received electric field strength (1-8). When the space utilization rate fluctuates, the directivity direction having a lower space utilization rate is selected as the communication route search direction (12-1), and the routing signal is transmitted again by the same process. The communication route is searched (1-5), and the communication route of the multi-hop communication is changed (1-6).

  In addition, when selecting a directivity direction having a relatively low space utilization rate as a route search direction, a configuration in which a predetermined number of directivity directions in order from a low space utilization rate are selected as the route search direction, or a space It can be configured that a predetermined number of directivity directions are determined as the congestion direction in descending order of usage rate, and a directivity direction other than the directivity direction is selected as the route search direction.

  In the first embodiment or the second embodiment described above, after the communication route is determined, multi-hop communication can be performed using the directional antenna 120 used for searching for the communication route. In the case of such a configuration, as a method of selecting the directional antenna 120 used for multi-hop communication, the received electric field strength of the radio signal emitted by the direct communication partner device (adjacent relay device) on the route determined by the routing is The used antenna determining unit 110 determines the highest directional antenna.

  A configuration in which the directional antenna having the highest received electric field strength is selected by the antenna control unit 111 as an antenna used for multi-hop communication, and multi-hop communication by the communication unit 112 is performed using the selected directional antenna 120. It can be.

  Further, as shown in FIG. 13, a storage area of the transmission antenna recording unit 13-1 is provided in the routing signal packet. When a routing signal is transmitted from a directional antenna in the route search direction, different antenna identification information for each directional antenna to be transmitted is stored and transmitted to the transmission antenna recording unit 13-1 for the routing signal.

  Upon receiving the routing signal storing the antenna identification information, the wireless communication apparatus having the destination address determines the communication route, and returns route confirmation information including the antenna identification information to the wireless communication apparatus having the transmission source address. In this way, the directional antenna that has transmitted the routing signal that has caused the determination of the communication route is recognized by the wireless communication device of the transmission source address, and the wireless communication device of the transmission source address transmits the routing signal. The selected directional antenna can be selected as an antenna for multi-hop communication.

  Further, as shown in FIG. 14, another antenna for communication 130 is separately prepared as an antenna used for multi-hop communication, instead of the directional antenna 120 used for routing, and multi-hop communication by the communication unit 112 is provided separately. The communication antenna 130 can be used.

  By doing this, even during multi-hop communication using the communication antenna 130, the space utilization rate is always calculated based on the received electric field strength of each directional antenna 120, and the routing signal is transmitted in the directional direction where the space utilization rate has decreased. The control operation is facilitated, and when the state of the surrounding wireless environment changes, the control operation for changing to a more optimal communication route following the change can be facilitated.

DESCRIPTION OF SYMBOLS 100 Wireless communication apparatus 120 Each antenna which has directivity 101 Received electric field strength measurement part 102 Strength judgment part 103 Space utilization factor calculation part 104 Space utilization factor recording part 105 Transmission direction judgment part 106 Routing signal transmission antenna control part 107 Routing signal preparation part 108 Utilization threshold value setting unit 109 Strength threshold value setting unit 110 Use antenna determination unit 111 Antenna control unit 112 Communication unit 113 Transmission direction comparison unit

Claims (8)

In a wireless communication apparatus having a multi-hop communication function and having a plurality of transmitting and receiving antennas with different directivity directions,
The received electric field strength for each directional direction is measured and compared with a predetermined strength threshold, and the ratio of the observation time of the received electric field strength exceeding the strength threshold is defined as the space utilization rate for each directional direction in the radio space. A space utilization rate calculating means for calculating;
Each space utilization rate for each directivity direction is compared with a predetermined utilization threshold value, and when there is a directivity direction with a space utilization factor equal to or less than at least one utilization factor threshold, the space utilization factor equal to or less than the utilization threshold value one of the directional direction, selected as the search direction of the communication route, when the orientation of the space utilization ratio which follows the utilization threshold has not been discovered one, a higher value of the usage rate threshold A search for re-selecting the direction of directivity with a space utilization factor equal to or lower than the higher utilization threshold value as the search direction of the communication route. Direction selection means,
Means for transmitting a routing signal for determining a communication route of multi-hop communication from the antenna in the directivity direction selected by the search direction selecting means;
After the start of multi-hop communication, if necessary, measure each received electric field strength for each directivity direction to calculate each space utilization rate, and based on the space utilization rate, the search direction selection means determines the communication route. Means for performing a search direction selection operation;
A wireless communication apparatus comprising: In a wireless communication apparatus having a multi-hop communication function and having a plurality of transmitting and receiving antennas with different directivity directions,
The received electric field strength for each directional direction is measured and compared with a predetermined strength threshold, and the ratio of the number of sampling times of the received electric field strength exceeding the strength threshold is defined as the space utilization rate for each directional direction in the wireless space. A space utilization rate calculating means for calculating;
Each space utilization rate for each directivity direction is compared with a predetermined utilization threshold value, and when there is a directivity direction with a space utilization factor equal to or less than at least one utilization factor threshold, the space utilization factor equal to or less than the utilization threshold value one of the directional direction, selected as the search direction of the communication route, when the orientation of the space utilization ratio which follows the utilization threshold has not been discovered one, a higher value of the usage rate threshold A search for re-selecting the direction of directivity with a space utilization factor equal to or lower than the higher utilization threshold value as the search direction of the communication route. Direction selection means,
Means for transmitting a routing signal for determining a communication route of multi-hop communication from the antenna in the directivity direction selected by the search direction selecting means;
After the start of multi-hop communication, if necessary, measure each received electric field strength for each directivity direction to calculate each space utilization rate, and based on the space utilization rate, the search direction selection means determines the communication route. Means for performing a search direction selection operation;
A wireless communication apparatus comprising: In a wireless communication apparatus having a multi-hop communication function and having a plurality of transmitting and receiving antennas with different directivity directions,
The received electric field strength for each directional direction is measured and compared with a predetermined strength threshold, and the ratio of the observation time of the received electric field strength exceeding the strength threshold is defined as the space utilization rate for each directional direction in the radio space. A space utilization rate calculating means for calculating;
Each space utilization rate for each directivity direction is compared with a predetermined utilization threshold value, and when there is a directivity direction with a space utilization factor equal to or less than at least one utilization factor threshold, the space utilization factor equal to or less than the utilization threshold value Is selected as the search direction for the communication route, and when no directivity direction having a space utilization rate equal to or lower than the utilization threshold value is found, the intensity threshold value is set to a higher value. In the space utilization rate calculating means, the higher intensity threshold value and the received electric field strength are compared to calculate a space utilization rate for each directivity direction in the wireless space, and the utilization rate is calculated using the space utilization rate. A search direction selection means for reselecting a directivity direction equal to or lower than a rate threshold as a search direction of the communication route;
Means for transmitting a routing signal for determining a communication route of multi-hop communication from the antenna in the directivity direction selected by the search direction selecting means;
After the start of multi-hop communication, if necessary, measure each received electric field strength for each directivity direction to calculate each space utilization rate, and based on the space utilization rate, the search direction selection means determines the communication route. Means for performing a search direction selection operation;
A wireless communication apparatus comprising: In a wireless communication apparatus having a multi-hop communication function and having a plurality of transmitting and receiving antennas with different directivity directions,
The received electric field strength for each directional direction is measured and compared with a predetermined strength threshold, and the ratio of the number of sampling times of the received electric field strength exceeding the strength threshold is defined as the space utilization rate for each directional direction in the wireless space. A space utilization rate calculating means for calculating;
Each space utilization rate for each directivity direction is compared with a predetermined utilization threshold value, and when there is a directivity direction with a space utilization factor equal to or less than at least one utilization factor threshold, the space utilization factor equal to or less than the utilization threshold value Is selected as the search direction for the communication route, and when no directivity direction having a space utilization rate equal to or lower than the utilization threshold value is found, the intensity threshold value is set to a higher value. In the space utilization rate calculating means, the higher intensity threshold value and the received electric field strength are compared to calculate a space utilization rate for each directivity direction in the wireless space, and the utilization rate is calculated using the space utilization rate. A search direction selection means for reselecting a directivity direction equal to or lower than a rate threshold as a search direction of the communication route;
Means for transmitting a routing signal for determining a communication route of multi-hop communication from the antenna in the directivity direction selected by the search direction selecting means;
After the start of multi-hop communication, if necessary, measure each received electric field strength for each directivity direction to calculate each space utilization rate, and based on the space utilization rate, the search direction selection means determines the communication route. Means for performing a search direction selection operation;
A wireless communication apparatus comprising: A communication route selection method for determining a communication route of a wireless communication device that performs multi-hop communication,
Measure the received electric field strength for each directivity direction received by a plurality of antennas with different directivity directions provided in the wireless communication device, compare with a predetermined strength threshold value, and observe the received electric field strength exceeding the strength threshold value A space utilization rate calculating step for calculating a time ratio as a space utilization rate for each pointing direction in the wireless space;
When there is a pointing direction of a spatial utilization factor equal to or less than the utilization threshold value of at least one, one of the directivity directions of the spatial utilization factor equal to or less than the utilization threshold value is selected as the search direction of the communication route; When no directivity direction of the space utilization rate that is equal to or lower than the utilization threshold value is found, the utilization threshold value is set to a higher value, and each space utilization factor for each directivity direction is set to a higher utilization threshold value. And a search direction selection step for reselecting the direction of directivity of the space utilization rate equal to or lower than the higher utilization rate threshold as the search direction of the communication route ;
Transmitting a routing signal for determining a communication route of multi-hop communication from the antenna in the directivity direction selected in the search direction selection step;
After the start of multi-hop communication, if necessary, measure each received electric field strength for each directivity direction to calculate each space utilization rate, and based on the space utilization rate, the search direction selection means determines the communication route. Carrying out a search direction selection operation;
A communication route selection method comprising: A communication route selection method for determining a communication route of a wireless communication device that performs multi-hop communication,
Sampling of received electric field intensity exceeding the intensity threshold by measuring each received electric field intensity for each directivity direction received by a plurality of antennas having different directivity directions provided in the wireless communication device A space utilization rate calculating step for calculating a ratio of the number of times as a space utilization rate for each pointing direction in the wireless space;
When there is a pointing direction of a spatial utilization factor equal to or less than the utilization threshold value of at least one, one of the directivity directions of the spatial utilization factor equal to or less than the utilization threshold value is selected as the search direction of the communication route; When no directivity direction of the space utilization rate that is equal to or lower than the utilization threshold value is found, the utilization threshold value is set to a higher value, and each space utilization factor for each directivity direction is set to a higher utilization threshold value. And a search direction selection step for reselecting the direction of directivity of the space utilization rate equal to or lower than the higher utilization rate threshold as the search direction of the communication route ;
Transmitting a routing signal for determining a communication route of multi-hop communication from the antenna in the directivity direction selected in the search direction selection step;
After the start of multi-hop communication, if necessary, measure each received electric field strength for each directivity direction to calculate each space utilization rate, and based on the space utilization rate, the search direction selection means determines the communication route. Carrying out a search direction selection operation;
A communication route selection method comprising: A communication route selection method for determining a communication route of a wireless communication device that performs multi-hop communication,
Measure the received electric field strength for each directivity direction received by a plurality of antennas with different directivity directions provided in the wireless communication device, compare with a predetermined strength threshold value, and observe the received electric field strength exceeding the strength threshold value A space utilization rate calculating step for calculating a time ratio as a space utilization rate for each pointing direction in the wireless space;
When there is a pointing direction of a spatial utilization factor equal to or less than the utilization threshold value of at least one, one of the directivity directions of the spatial utilization factor equal to or less than the utilization threshold value is selected as the search direction of the communication route; When no directivity direction of the space utilization rate that is equal to or less than the utilization threshold value is found, the intensity threshold value is set to a higher value, and the space utilization factor calculating unit determines the higher intensity threshold value and the received electric field strength. To calculate a space utilization rate for each directivity direction in the wireless space, and use the space utilization rate to reselect a directivity direction that is equal to or less than the utilization threshold as the search direction for the communication route. A selection step;
  Transmitting a routing signal for determining a communication route of multi-hop communication from the antenna in the directivity direction selected in the search direction selection step;
After the start of multi-hop communication, if necessary, measure each received electric field strength for each directivity direction to calculate each space utilization rate, and based on the space utilization rate, the search direction selection means determines the communication route. Carrying out a search direction selection operation;
A communication route selection method comprising: A communication route selection method for determining a communication route of a wireless communication device that performs multi-hop communication,
Sampling of received electric field intensity exceeding the intensity threshold by measuring each received electric field intensity for each directivity direction received by a plurality of antennas having different directivity directions provided in the wireless communication device A space utilization rate calculating step for calculating a ratio of the number of times as a space utilization rate for each pointing direction in the wireless space;
When there is a pointing direction of a spatial utilization factor equal to or less than the utilization threshold value of at least one, one of the directivity directions of the spatial utilization factor equal to or less than the utilization threshold value is selected as the search direction of the communication route; When no directivity direction of the space utilization rate that is equal to or less than the utilization threshold value is found, the intensity threshold value is set to a higher value, and the space utilization factor calculating unit determines the higher intensity threshold value and the received electric field strength. To calculate a space utilization rate for each directivity direction in the wireless space, and use the space utilization rate to reselect a directivity direction that is equal to or less than the utilization threshold as the search direction for the communication route. A selection step;
Transmitting a routing signal for determining a communication route of multi-hop communication from the antenna in the directivity direction selected in the search direction selection step;
After the start of multi-hop communication, if necessary, measure each received electric field strength for each directivity direction to calculate each space utilization rate, and based on the space utilization rate, the search direction selection means determines the communication route. Carrying out a search direction selection operation;
A communication route selection method comprising:

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