JP2016171518A - Radio communication device and radio communication program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an optimal transmission output value for each communication path according to an environment change, communication quality etc. from the reception power value of a reception signal.SOLUTION: A radio communication device includes: signal type discrimination means for discriminating whether or not a signal is a broadcast signal; reception power value measurement means for measuring the reception power value of the broadcast signal; transmission output value calculation means for obtaining a transmission output value to be received in the next destination with a target reception power value for each communication path, using a route loss value based on the prescription transmission output value of the broadcast signal and the reception power value measured by the reception power value measurement means; transmission output value holding means which holds the transmission output value obtained by the transmission output value calculation means for each communication path; and transmission means for transmitting a signal using the transmission output value for each communication path held in the transmission output value holding means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless communication apparatus and a wireless communication program, and can be applied to, for example, a wireless communication apparatus that performs wireless multi-hop communication.

  For example, in the case of a wireless communication device in which the transmission output value is fixed at a predetermined value and the transmission output value cannot be controlled, the transmission-side wireless communication device is always the maximum even if the reception-side wireless communication device exists in the vicinity. Radio wave is transmitted with the output value of. For this reason, the radio wave reaches the other wireless communication device beyond the wireless communication device on the receiving side, and may become noise for the other wireless communication device.

  Further, by transmitting radio waves with a transmission output value that is higher than necessary, unnecessary power consumption is involved, and the operation time is also affected if a battery-driven device is used.

  In order to minimize the influence on other wireless communication devices and reduce power consumption, it is necessary to control the transmission output value to an optimum value according to the distance relationship with the destination. However, the distance to the destination is not only based on the physical positional relationship, but it is necessary to consider the influence of the presence or absence of obstacles on the communication path and the presence or absence of ambient noise.

  The technology described in Patent Document 1 is that when nodes constituting a wireless multi-hop network transmit / receive received radio wave status to / from adjacent nodes and radio waves arrive from adjacent nodes that are not direct paths, The transmission power is reduced to such an extent that communication with adjacent nodes on the route does not become unstable.

JP 2011-146850 A

  However, if the transmission output value is uniformly controlled in accordance with the adjacent nodes as in the prior art, there may be a problem that the communicable area becomes narrower than the original capability of the wireless communication apparatus. In particular, in the case of wireless multi-hop communication in which communication is performed via a plurality of wireless communication devices, it is not possible to detect a detourable path when communication fails due to narrowing of the communicable area, or newly installed This leads to the failure to find a wireless communication device. From this point of view, it may occur that it is not always desirable to uniformly control the transmission output value.

  Therefore, wireless communication that can control the transmission output value of radio waves by calculating the optimal transmission output value for each communication path from the received power value of the received signal according to environmental fluctuations or changes in communication quality due to obstacles, etc. There is a need for an apparatus and a wireless communication program.

  In order to solve such a problem, the wireless communication apparatus according to the first aspect of the present invention includes: (1) a signal type determining unit that determines whether or not a broadcast signal is based on transmission destination address information of a received signal; and (2) A received power value measuring means for measuring the received power value of the broadcast signal discriminated by the signal type discriminating means; and (3) a route based on the prescribed transmission output value of the broadcast signal and the received power value measured by the received power value measuring means. A transmission output value calculating means for obtaining for each communication path a transmission output value to be received at the next destination at the target reception power value using the loss value; and (4) communicating the transmission output value obtained by the transmission output value calculating means. Transmission output value holding means for holding each path, and (5) transmission means for transmitting a signal using the transmission output value for each communication path held in the transmission output value holding means. It is characterized in.

  According to a second aspect of the present invention, there is provided a wireless communication program, comprising: (1) signal type determining means for determining whether or not a broadcast signal is based on transmission destination address information of a received signal; and (2) signal type determining means. Received power value measuring means for measuring the received power value of the broadcast signal, (3) using the specified transmission output value of the broadcast signal and the path loss value based on the received power value measured by the received power value measuring means, Transmission output value calculation means for obtaining for each communication path a transmission output value to be received at the target reception power value at the destination of (4) transmission output value for holding for each communication path the transmission output value obtained by the transmission output value calculation means Holding means, and (5) functioning as a transmission means for transmitting a signal using the transmission output value for each communication path held in the transmission output value holding means. And butterflies.

  According to the present invention, it is possible to control the transmission output value of a radio wave by calculating an optimal transmission output value for each communication path from the reception intensity of the received signal in accordance with an environmental change or a change in communication quality due to an obstacle. it can.

It is an internal block diagram which shows the internal structure of the radio | wireless communication apparatus which concerns on 1st Embodiment. 1 is an overall configuration diagram showing an overall configuration of a wireless communication network according to a first embodiment. 4 is a flowchart illustrating an operation of a transmission control process in the wireless communication apparatus according to the first embodiment. It is explanatory drawing explaining the calculation process of the transmission output value by the optimal transmission output value calculation part which concerns on 1st Embodiment. It is an internal block diagram which shows the internal structure of the radio | wireless communication apparatus which concerns on 2nd Embodiment. 4 is a flowchart illustrating an operation of a transmission control process in the wireless communication apparatus according to the first embodiment. It is a block diagram which shows the structure of the offset table which concerns on 2nd Embodiment. It is explanatory drawing explaining the calculation process of the transmission output value by the optimal transmission output value calculation part which concerns on 2nd Embodiment. It is explanatory drawing explaining control of the transmission output value of the broadcast signal which concerns on 3rd Embodiment.

(A) First Embodiment Hereinafter, a first embodiment of a wireless communication apparatus and a wireless communication program according to the present invention will be described in detail with reference to the drawings.

  1st Embodiment illustrates the case where this invention is applied to the radio | wireless communication apparatus which employ | adopts multihop communication and comprises an ad hoc network, for example.

(A-1) Configuration of the First Embodiment FIG. 2 is an overall configuration diagram showing the overall configuration of the wireless communication network 1 according to the first embodiment. 2, the wireless communication network 1 according to the first embodiment includes a plurality (five in FIG. 2) of wireless communication devices 100-1 to 100-5. In addition, since each of the plurality of wireless communication devices 100-1 to 100-5 has a common functional configuration, when describing the common configuration and processing, the wireless communication devices 100-1 to 100-5 are described as the wireless communication device 100. .

  The wireless communication device 100 is a wireless communication device mounted on a node constituting an ad hoc network, and performs multi-hop communication with a nearby wireless communication device 100. Further, the wireless communication device 100 can be moved by being mounted on a movable node or the like.

  The wireless communication device 100 transmits / receives a route search signal by broadcasting to search for a communication route and create a communication route table, or a distant wireless communication device via a nearby wireless communication device 100 Multi-hop function for performing multi-hop communication with 100, and a transmission output control function for calculating a transmission output value for each communication path based on a received power value (for example, received electric field strength) received during broadcast communication Etc.

  The wireless communication apparatus 100 is compatible with any one communication method of one-to-unspecified many broadcast communication, one-to-many multicast communication, and one-to-one unicast communication. Image data) and other wireless communication devices 100 are transmitted and received.

  FIG. 1 is an internal configuration diagram showing an internal configuration of the wireless communication apparatus 100 according to the first embodiment. In FIG. 1, the wireless communication apparatus 100 according to the first embodiment roughly includes a reception unit 101, a transmission output value control unit 110, and a transmission unit 106. The transmission output value control unit 110 includes a reception power value measurement unit 102, an optimum transmission output value calculation unit 103, a transmission output value holding unit 104, and a communication path search unit 105.

  Although the hardware configuration of the wireless communication device 100 is not shown, the communication control unit including the antenna unit, the communication unit including the communication interface, the communication control unit, and the like, as in the existing wireless communication device, the processing program By executing the above, the function of the wireless communication apparatus 100 is realized.

  The receiving unit 101 receives a signal placed on a radio wave captured by an antenna unit (not shown) of the wireless communication apparatus 100 and analyzes the received signal. The receiving unit 101 includes a communication type determining unit 111 that analyzes the decoded signal and determines the type of communication method based on address information included in the header information.

  The communication type determining unit 111 determines whether the received address signal is a broadcast address that does not specify a destination or a unicast address that specifies a specific destination, by determining whether the destination address information included in the header information is a destination address. It is determined whether the signal is a broadcast signal or a unicast signal.

  When the communication type determination unit 111 determines that the reception unit 101 is a broadcast signal, the reception unit 101 gives the reception signal to the reception power value measurement unit 102. If it is determined that the received signal is a unicast signal and the destination is the local apparatus, the data included in the received signal is given to the upper layer. On the other hand, when the destination is another wireless communication device, the packet is transferred to the wireless communication device of the next hop destination according to the designated communication path.

  The reception power value measurement unit 102 measures the reception power value (reception electric field strength) of the received broadcast signal, and gives the measurement result to the optimum transmission output value calculation unit 103.

  The optimum transmission output value calculation unit 103 obtains the path loss of the communication path based on the received electric field strength of the broadcast signal acquired from the received power value measurement unit 102, and based on this path loss, transmits the unicast that the device itself transmits. A signal transmission output value is calculated for each communication path.

  That is, the optimum transmission output value calculation unit 103 obtains a path loss corresponding to the communication environment of the communication path from the received electric field strength of the received broadcast signal. And the optimal transmission output value calculation part 103 calculates the transmission output value at the time of the said radio | wireless communication apparatus 100 performing unicast communication for every communication path.

  Here, when performing broadcast communication, a transmission output value standardized by a communication protocol is used as a transmission output value for transmitting a broadcast signal. That is, generally, the wireless communication device 100 on the transmission side that transmits a broadcast signal transmits the broadcast signal with a transmission output value defined by the communication protocol.

  On the other hand, since the wireless communication apparatus 100 on the receiving side that receives the broadcast signal recognizes the transmission output value of the broadcast signal, the optimum transmission output value calculation unit 103 determines the transmission output value of the broadcast signal and the reception electric field of the broadcast signal. Based on the strength, the path loss can be obtained.

  Then, the optimum transmission output value calculation unit 103 obtains the transmission output value of the unicast signal by using the path loss obtained at the time of receiving the broadcast signal as the path loss at the time of transmitting the unicast signal. That is, at the time of transmission of a unicast signal, the minimum received electric field strength in the wireless communication device 100 on the receiving side is recommended by the wireless communication protocol for stable reception of the unicast signal. Therefore, the optimum transmission output value calculation unit 103 calculates the transmission output value of the unicast signal by adding the path loss at the time of reception of the broadcast signal to the recommended minimum reception electric field strength of the unicast signal. .

  The transmission output value holding unit 104 holds the transmission output value of the communication path calculated by the optimum transmission output value calculation unit 103 for each communication path.

  The communication path search unit 105 creates or updates a path table by checking the status of the surrounding wireless communication devices 100 according to a predetermined communication path search protocol. The communication route search protocol is not particularly limited, and various protocols can be widely applied. For example, RPL (IPv6 Routing Protocol for Low power and Lossy networks), AODV (Ad hoc On-Demand Distance Vector) OLSR (Optimized Link State Routing), DYMO (Dynamic MANET On-demand), DSR (Dynamic Source Routing), and the like can be applied.

  The transmission unit 106 transmits a transmission signal including transmission data by broadcast or unicast. When the transmission unit 106 transmits a unicast signal, the transmission output value of the corresponding communication path is read from the transmission output holding unit 104 according to the destination of the unicast signal, and the unicast signal is transmitted using the transmission output value of the communication path. Send.

(A-2) Operation of First Embodiment Next, the processing operation of transmission output control in the wireless communication apparatus 100 of the first embodiment will be described in detail with reference to the drawings.

  FIG. 3 is a flowchart showing the operation of the transmission control process in the wireless communication apparatus 100 according to the first embodiment.

  An antenna unit (not shown) of the wireless communication apparatus 100 receives the arrived radio wave, and a signal placed on the radio wave is given to the receiving unit 101. When the signal is received by the receiving unit 101 (S101), the destination address information included in the header of the received signal is analyzed to determine whether or not it is a broadcast signal (S102). When it is determined that the received signal is a broadcast signal, the received power value measuring unit 102 measures the received electric field strength of the broadcast signal (S103).

  In the optimum transmission output value calculation unit 103, the path loss of the communication path is obtained based on the reception electric field strength of the broadcast signal measured by the reception power value measurement unit 102, and the transmission output value of the unicast signal is calculated. The transmission output value calculation process by the optimum transmission output value calculation unit 103 will be described in detail with reference to FIGS.

  FIG. 4 is an explanatory diagram illustrating transmission output value calculation processing by the optimum transmission output value calculation unit 103 according to the first embodiment. FIG. 4 shows the relationship between the received power value or the transmitted power value of the signals of the wireless communication device A and the wireless communication device B.

  In FIG. 4, the wireless communication device B is a broadcast signal transmission side, the wireless communication device A is a broadcast signal reception side, and the wireless communication device A is a unicast signal destined for the wireless communication device B. The case where is transmitted is illustrated.

In FIG. 4, the wireless communication apparatus B transmits a broadcast signal with a transmission output value T _B [dBm].

It is assumed that the broadcast signal is received by the wireless communication device A and received by the reception power value measuring unit 102 of the wireless communication device A at the reception electric field strength R _BA [dBm] of the broadcast signal.

At this time, since the optimum transmission output value calculation unit 103 of the wireless communication apparatus A recognizes the transmission output value T _B [dBm] of the broadcast signal, the transmission output value T _B [ Based on dBm] and the received electric field strength R _BA [dBm] of the broadcast signal, path loss L _AB [dB] of the communication path is calculated (S104).
L _AB [dB] = T _B −R _AB (1)

Next, the optimum transmission output value calculation unit 103 of the wireless communication device A performs path loss L _AB [dB] with the wireless communication device B and unicast defined by the wireless communication system according to the equation (2). Based on the minimum received electric field strength C of the signal, a transmission output value U _AB [dBm] of the unicast signal is calculated (S105).
U _AB [dBm] = C + L _AB = C + (T _B −R _AB ) (2)

As shown in FIG. 4, since the transmission output value of the broadcast signal is recognized, the wireless communication device A can measure the reception electric field strength of the broadcast signal in the wireless communication device A on the receiving side, so that the wireless communication device A The path loss L _AB [dBm] of the communication path between and can be obtained.

Further, when the wireless communication device A transmits a unicast signal destined for the wireless communication device B, the minimum received electric field strength C on the receiving side of the unicast signal is defined by the wireless communication system. Therefore, the radio communication apparatus A obtains the transmission output value U _AB [dBm] of the unicast signal according to the equation (2) in consideration of receiving the unicast signal with the minimum received electric field strength C.

  The transmission output value of the unicast signal calculated by the optimum transmission output value calculation unit 103 is given to the transmission output value holding unit 104, and is held for each communication path in the transmission output value holding unit 104 (S106).

  Thereafter, when the wireless communication device A transmits a unicast signal to the wireless communication device B, the transmission unit 106 of the wireless communication device A sets a transmission output value between the wireless communication device B as a destination or a relay destination. Read and transmit a unicast signal with the transmission output value.

  By doing so, it is possible to control the transmission output value of the unicast signal to a specific destination without controlling the transmission output value of the broadcast signal. In other words, since the transmission output value of the broadcast signal is not controlled, it is possible to avoid narrowing the area in which broadcast communication can be performed, and it is possible to provide a function specific to broadcast communication (for example, a communication route search function). On the other hand, since unicast communication is one-to-one communication, it can be set to a transmission output value sufficient to allow radio waves to reach a specific radio communication device, suppress radio wave interference to other radio communication devices, and Therefore, power saving can be achieved.

(A-3) Effect of First Embodiment As described above, according to the first embodiment, the transmission output value of the unicast signal for each communication path is calculated based on the reception power value of the broadcast signal. Thus, when transmitting a unicast signal, it is possible to transmit with an optimal transmission output value of the communication path.

  As a result, the transmission output of the broadcast signal is not controlled, and only the unicast signal is controlled to the transmission output according to the destination, thereby suppressing radio wave interference to surrounding wireless communication devices without narrowing the communicable area, Expect power-saving operation.

(B) Second Embodiment Next, a second embodiment of the wireless communication apparatus and the wireless communication program according to the present invention will be described in detail with reference to the drawings.

  Similarly to the first embodiment, the second embodiment exemplifies a case where the present invention is applied to a wireless communication device that configures an ad hoc network, for example, employing multi-hop communication.

(B-1) Configuration of the Second Embodiment In the second embodiment, the transmission output value of a unicast signal is considered in consideration of fluctuations in the received electric field strength of the broadcast signal according to changes in the communication path environment. Is different from the first embodiment in that

  FIG. 5 is an internal configuration diagram showing an internal configuration of the wireless communication apparatus 100 according to the second embodiment. In FIG. 5, the wireless communication apparatus 100 according to the second embodiment roughly includes a reception unit 101, a transmission output value control unit 210, and a transmission unit 106. The transmission output value control unit 210 includes a reception power value measurement unit 102, an optimum transmission output value calculation unit 203, a transmission output value holding unit 204, a communication path search unit 105, and a loss rate calculation unit 207.

  In addition, the same code | symbol as FIG. 1 is attached | subjected about the same or corresponding component of the radio | wireless communication apparatus 100 which concerns on 1st Embodiment.

  The loss rate calculation unit 207 calculates the loss rate of the broadcast signal based on each communication path. Various methods can be applied to the loss rate calculation method by the loss rate calculation unit 207. For example, the number of broadcast signal transmissions per predetermined unit time and the number of response signal receptions for the transmitted broadcast signals Based on this, a method for obtaining the signal loss rate per unit time for each communication path can be used. By obtaining the loss rate for each communication path, the communication environment of that communication path can be obtained. That is, when the loss rate is relatively small, it is possible to determine that the communication environment is relatively good because the broadcast signal can be continuously received. Conversely, when the loss rate is relatively large, it can be determined that the communication environment is relatively poor.

  The optimum transmission output value calculation unit 203 obtains the path loss of the communication path based on the reception electric field strength of the broadcast signal acquired from the reception power value measurement unit 102.

  Here, the optimum transmission output value calculation unit 203 according to the second embodiment changes the reception electric field strength of the broadcast signal according to the change in the communication environment of the communication path. The average value RA [dBm] is used. That is, the average value RA [dBm] of the received electric field strength at a predetermined number of receptions is obtained, and the path loss of the communication path is obtained based on the average value of the received electric field strength. As a result, the received electric field strength also fluctuates in accordance with the environmental change. Therefore, the average value RA [dBm] of the received electric field strength over a predetermined number of times according to the environmental variation is used instead of every reception of the broadcast signal. Can adapt to fluctuations.

  Further, the optimum transmission output unit 203 refers to the offset table 204 a held in the transmission output value holding unit 204 to obtain an offset value corresponding to the missing rate of the communication path obtained by the missing rate calculation unit 207.

  Furthermore, the optimum transmission output unit 203 is defined by the wireless communication system, the path loss for each communication path based on the average value RA [dBm] of the received electric field strength, the offset value corresponding to the missing rate of the communication path, and the like. A transmission output value of the unicast signal is calculated based on the minimum received electric field strength of the unicast signal.

  Similarly to the first embodiment, the transmission output value holding unit 204 holds the transmission output value of the communication path calculated by the optimum transmission output value calculation unit 203 for each communication path. In addition, in order to calculate the average value of the received electric field strength by the optimum transmission output value calculating unit 203, the transmission output value holding unit 204 holds the received electric field strength of a predetermined number of times in the past or holds the average value of the past received electric field strength. To do. Further, the transmission output value holding unit 204 holds an offset table 204a for determining an offset value corresponding to the communication path loss rate.

(B-2) Operation of Second Embodiment Next, the processing operation of the transmission output control in the wireless communication apparatus 100 of the second embodiment will be described in detail with reference to the drawings.

  FIG. 6 is a flowchart showing the operation of the transmission control process in the wireless communication apparatus 100 according to the first embodiment.

  As in the first embodiment, when a signal is received by the receiving unit 101 of the wireless communication apparatus 100 (S101), the destination address information included in the header of the received signal is analyzed and a broadcast signal is obtained. It is determined whether or not (S102). When it is determined that the received signal is a broadcast signal, the received power value measuring unit 102 measures the received electric field strength of the broadcast signal (S103).

  The optimum transmission output value calculation unit 203 calculates the average value RA [dBm] of the received electric field strength for a predetermined number of times including the past and current received electric field strengths (S201).

  Furthermore, the optimum transmission output value calculation unit 203 obtains the missing rate of the communication path obtained by the missing rate calculation unit 207, refers to the offset table 204a, and sets the offset value O corresponding to the missing rate of the communication path. Is obtained (S202).

  FIG. 7 is a configuration diagram showing the configuration of the offset table 204a according to the second embodiment. As shown in FIG. 7, the offset value 204 is associated with the offset table 204a according to the missing rate. For example, in the case of “missing rate: 1% or more and less than 10%”, it can be determined that the communication environment is stable and good as the missing rate becomes smaller, such as “offset value: 3 [dBm]”. Therefore, the offset value becomes small. Conversely, the greater the missing rate, the greater the offset value because it can be determined that the communication environment is unstable.

Since the optimum transmission output value calculation unit 203 recognizes the transmission output value T _B [dBm] of the broadcast signal, the transmission output value T _B [dBm] of the broadcast signal and the broadcast signal are calculated according to Equation (3). Based on the average value RA _BA [dBm] of the received electric field strength, the path loss L _AB [dB] of the communication path is calculated (S203).
L _AB [dB] = T _B −RA _AB (3)

Next, the optimum transmission output value calculation unit 203 is defined by the wireless communication system and the path loss L _AB [dB] with the wireless communication apparatus that is the next hop destination of the communication path according to the equation (4). The transmission output value U _AB [dBm] of the unicast signal is calculated based on the minimum received electric field strength C of the unicast signal and the offset value O (S204).
U _AB [dBm] = C + L _AB + O = C + (T _B −RA _AB ) + O (4)

  The transmission output value of the unicast signal calculated by the optimum transmission output value calculation unit 203 is given to the transmission output value holding unit 204, and is held for each communication path in the transmission output value holding unit 204 (S106).

  Thereafter, when the wireless communication device 100 transmits a unicast signal to the destination wireless communication device, the transmission unit 106 of the wireless communication device reads a transmission output value between the wireless communication device as the destination and transmits the transmission output value. A unicast signal is transmitted with the output value.

  FIG. 8 is an explanatory diagram illustrating transmission output value calculation processing by the optimum transmission output value calculation unit 203 according to the second embodiment. FIG. 8 shows the relationship between the received power value or the transmitted power value of the signals of the wireless communication device A and the wireless communication device B.

  In FIG. 8, the wireless communication device B is a broadcast signal transmission side, the wireless communication device A is a broadcast signal reception side, and the wireless communication device A has the wireless communication device B as a destination or a relay destination. The case where a unicast signal is transmitted is illustrated.

In FIG. 8, the wireless communication device B transmits a broadcast signal with an output value of T _B = 20 [mW] = 13 [dBm]. Assume that the wireless communication apparatus A receives the broadcast signal transmitted from the wireless communication apparatus B and calculates the average reception intensity RA _BA = −70 [dBm] for a predetermined number of times. Further, it is assumed that the missing rate for the signal between the wireless communication device A and the wireless communication device B is the missing rate P _BA = 5 [%].

In this case, in the wireless communication apparatus A, the optimum transmission output value calculation unit 203 refers to the offset table 204a (see FIG. 7), and the offset value O _BA = 3 [corresponding to the missing rate P _BA = 5 [%]. dBm].

Therefore, the optimum transmission output value calculation unit 203 of the wireless communication device A calculates the path loss L _AB [dB] = T _B −RA _BA = 13 − (− 70) = 83 [dBm] with the wireless communication device B. Ask.

Furthermore, assuming that the minimum reception strength C of a unicast signal in a wireless communication system is C = −100 [dBm], an optimal transmission output value U when performing unicast communication from the wireless communication apparatus A to the wireless communication apparatus B _AB [dBm] becomes U _AB = C + L _AB + O _BA = −100 + 83 + 3 = −14 [dBm].

Therefore, in the wireless communication device A, the optimum transmission output value calculation unit 203 holds U _AB = −14 [dBm] in the transmission output value holding unit 204 as the transmission output value of the unicast signal for the wireless communication device B.

(B-3) Effects of the Second Embodiment As described above, according to the second embodiment, the optimum transmission output value of the unicast signal in consideration of the average received electric field strength and the loss rate of the broadcast signal. Can be obtained for each wireless communication device. As a result, it is possible to prevent a communication failure due to a change in the communication path environment.

  In addition, according to the second embodiment, the broadcast signal includes a signal that is periodically transmitted to notify the communication quality of the wireless communication device itself. It is possible to know fluctuations in electric field strength and signal loss rate.

(C) Third Embodiment Next, a third embodiment of the wireless communication apparatus and the wireless communication program according to the present invention will be described in detail with reference to the drawings.

  Similarly to the first and second embodiments, the third embodiment exemplifies a case where the present invention is applied to a wireless communication device that configures an ad hoc network by adopting, for example, multihop communication.

(C-1) Configuration and Operation of Third Embodiment In the first and second embodiments, transmission output control of a unicast signal has been described. On the other hand, 3rd Embodiment illustrates the case where the transmission output value of a broadcast signal is also controlled.

  The configuration of the wireless communication apparatus according to the third embodiment includes the same or corresponding configuration as the configuration of the wireless communication apparatus according to the first and second embodiments. Accordingly, the third embodiment will be described with reference to FIGS. 1 and 5 according to the first and second embodiments.

  It is considered that it is sufficient for the broadcast signal to reach the farthest wireless communication device 100 among the plurality of wireless communication devices 100 existing in the vicinity of the wireless communication device 100. Therefore, the optimum transmission output value of the unicast signal with the farthest wireless communication apparatus 100 is used as the transmission output value of the broadcast signal.

  In this case, the communicable area becomes narrower than the original capability. However, for example, when the wireless communication device 100 receives a connection signal from the wireless communication device 100 newly installed outside the area, the transmission output value is optimized with the new wireless communication device 100 as the farthest wireless communication device 100. If the transmission output value 103 or 203 is recalculated, the communicable area can be expanded each time.

  For example, when the wireless communication device 100 searches for surrounding wireless communication devices when the power is turned on or when rejoining from a network disconnected state, the maximum transmission output value defined by the setting of the wireless communication system or the wireless communication device is used. A connection signal is transmitted by broadcasting.

  FIG. 9 is an explanatory diagram for explaining the control of the transmission output value of the broadcast signal according to the third embodiment.

As shown in FIG. 9A, it is assumed that a wireless communication device B, a wireless communication device C, and a wireless communication device D exist around the wireless communication device A. In the wireless communication device A, the optimum transmission output values of the unicast signals for the wireless communication devices B, C, and D are U _AB = −7 [dBm], U _AC = −15 [dBm], and U _AD = 0 [ dBm]. The calculation method of the optimum transmission output value of the unicast signal is obtained by the same method as in the first and second embodiments.

At this time, for the wireless communication device A, the farthest wireless communication device is considered to be the wireless communication device D having the largest optimum transmission output value. Therefore, in the wireless communication apparatus A, the transmission output value T _A [dBm] of the broadcast signal can also be reduced to a transmission output value U _AD = 0 [dBm] sufficient to reach the wireless communication apparatus D.

Thereafter, it is assumed that the wireless communication device E is installed far away from the wireless communication device D. At this time, since the wireless communication device A has the transmission output value T _A = U _AD = 0 [dBm] of the broadcast signal, the broadcast signal of the wireless communication device A does not reach the wireless communication device E.

  In contrast, the wireless communication device E transmits a connection signal with a maximum transmission output value in order to participate in the network. Therefore, the wireless communication device A can receive the connection signal (broadcast signal) transmitted by the wireless communication device E.

  Therefore, the wireless communication device A can detect that the wireless communication device E is installed.

Here, the wireless communication device A calculates the optimum transmission output _UAE of the unicast signal for the wireless communication device E by the method for calculating the transmission output value of the unicast signal described in the first and second embodiments. It is held in the transmission output value holding unit 104.

  In the wireless communication apparatus A, when the transmission unit 106 transmits a broadcast signal, the transmission unit 106 has the largest transmission output value among the transmission output values of the unicast signal held in the transmission output value holding unit 104. To extract.

  The transmission unit 106 compares the transmission output value of the current broadcast signal with the extracted transmission output value of the unicast signal. When the transmission output value of the unicast signal is larger than the transmission output value of the current broadcast signal, the transmission unit 106 updates the transmission output value of the broadcast signal.

More specifically, when the transmission output value T _A <U _AE of the broadcast signal in the wireless communication apparatus _A , the transmission unit 106 changes to T _A = U _AE because the broadcast signal reaches the wireless communication apparatus E. To do.

  And the transmission part 106 transmits a broadcast signal using the transmission output value after a change.

(C-2) Effects of the Third Embodiment As described above, according to the third embodiment, not only the transmission output value of the unicast signal but also the transmission output of the broadcast signal is controlled. It is possible to further suppress radio wave interference with the wireless communication device and to operate with power saving.

(D) Other Embodiments Although various modified embodiments have been mentioned in the above-described embodiments, the present invention can also be applied to the following modified embodiments.

  (D-1) In the first to third embodiments described above, the case where the transmission output value of the unicast signal is calculated based on the reception electric field strength of the broadcast signal has been exemplified. However, depending on the usage of the broadcast signal, there is a case where it is not always necessary to reach all the wireless communication devices in the communicable area.

  In such a case, the use and type of the broadcast signal used for calculating the optimum transmission output value are determined, and based on the received electric field strength of a specific type of broadcast signal (for example, notification of timing synchronization or communication quality information). The transmission output value of the cast signal may be calculated.

  (D-2) In the first to third embodiments described above, in order for the wireless communication apparatus B to know the transmission output value of the broadcast signal, the wireless communication apparatus transmits the data included in the broadcast signal. You may make it provide the function to notify a transmission output, or the function to acquire a transmission output value by communication between radio | wireless communication apparatuses separately.

  (D-3) In 2nd Embodiment mentioned above, the case where the offset value according to a missing rate was calculated | required using the offset table as calculation of an offset value was illustrated. However, an offset value corresponding to the missing rate may be obtained using a predetermined function expression. The method for calculating the missing rate may be obtained, for example, by transmitting a broadcast signal every predetermined unit time (for example, 10 seconds) and monitoring the response of the response signal to the broadcast signal.

  DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 100 ... Wireless communication apparatus, 101 ... Reception part, 110 and 210 ... Transmission output value control part, 106 ... Transmission part, 102 ... Received power value measurement part, 103 and 203 ... Optimal transmission output value calculation part 104 and 204 ... transmission output value holding unit, 105 ... communication path search unit 105, 207 ... missing rate calculation unit.

Claims (7)

A signal type determining means for determining whether or not it is a broadcast signal based on the address information of the received signal;
Received power value measuring means for measuring the received power value of the broadcast signal determined by the signal type determining means;
Using the specified transmission output value of the broadcast signal and the path loss value based on the received power value measured by the received power value measuring means, the transmission output value to be received at the target received power value at the next destination is set for each communication path. A transmission output value calculation means to obtain,
Transmission output value holding means for holding the transmission output value obtained by the transmission output value calculating means for each communication path;
A wireless communication apparatus comprising: a transmission unit configured to transmit a signal using a transmission output value for each communication path held in the transmission output value holding unit.   2. The radio communication apparatus according to claim 1, wherein the transmission output value calculation means obtains the transmission output value for each communication path by adding the path loss value to the target received power value at the next destination.   The transmission output value calculation means obtains a path loss value over time according to the state of the communication environment based on the specified transmission output value of the broadcast signal and the received power value, and uses the path loss value over time. The wireless communication apparatus according to claim 1, wherein the transmission output value is obtained for each communication path. A communication quality state measuring means for measuring a communication quality state with a transmission source of the received broadcast signal;
The transmission output value calculation means obtains the transmission output value for each communication path by adding the path loss value or the time-lapse path loss value and the offset value corresponding to the communication quality state to the target reception power value. The wireless communication apparatus according to claim 2, wherein the wireless communication apparatus is a wireless communication apparatus.   5. The wireless communication according to claim 1, wherein the transmission unit transmits the unicast signal with the transmission output value for each destination of the unicast signal held in the transmission output holding unit. apparatus.   The transmission means refers to the transmission output value for each communication path held in the transmission output holding means, and changes the transmission output value of the broadcast signal according to the type of the broadcast signal. The radio | wireless communication apparatus in any one of 1-5. Computer
A signal type discriminating means for discriminating whether or not it is a broadcast signal based on the destination address information of the received signal;
Received power value measuring means for measuring the received power value of the broadcast signal determined by the signal type determining means;
Using the specified transmission output value of the broadcast signal and the path loss value based on the received power value measured by the received power value measuring means, the transmission output value to be received at the target received power value at the next destination is set for each communication path. A transmission output value calculation means to obtain,
Transmission output value holding means for holding the transmission output value obtained by the transmission output value calculating means for each communication path;
A wireless communication program that functions as a transmission unit that transmits a signal using a transmission output value for each communication path held in the transmission output value holding unit.

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