JP2018139381A - Communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device capable of improving communication quality even when selection of a frequency band cannot obtain high communication quality.SOLUTION: The communication device includes: a determination unit of determining a reception state of a second radio wave transmitted from a communication destination transmitting a second radio wave of a second frequency band and second transmission power when a first radio wave including second frequency band information showing the second frequency band and second transmission power information showing second transmission power is received; a setting unit of setting the second frequency band and the second transmission power according to a determination result from the determination; a transmission unit of transmitting, to the communication destination, the first radio wave including the second frequency band information showing the second frequency band in which the setting has been executed and the second transmission power information showing the second transmission power in which the setting has been executed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to frequency-variable wireless communication.

  A frequency band used for wireless communication is allocated for each communication service such as commercial wireless, mobile phone, and wireless LAN. Then, since communication states are overcrowded in some communication services and communication states are sparse in other communication services, communication quality varies for each communication service.

  Cognitive radio is known as a method that can solve this problem (see Non-Patent Documents 1 and 2). Cognitive radio includes a technology in which a selected frequency band is freely used without assigning a frequency band to each communication service.

  Here, Patent Document 1 acquires data, recognizes a frequency band having a low reception level based on the magnitude of the reception level of radio waves in the surrounding area, sets it as a reference frequency band, and uses the set reference frequency band. A modulation device for modulating acquired data is disclosed.

  Patent Document 2 discloses a method for allocating transmission power to a second communication service that secondarily uses a frequency band allocated to the first communication service.

  Further, in relation to the present invention, Patent Document 3 discloses a method for changing the frequency of a radio wave.

  Further, in relation to the present invention, Non-Patent Document 3 discloses a receiving circuit for cognitive radio.

JP 2003-333004 A JP 2011-50032 A International Publication No. 2005/093956

Wikipedia Free Encyclopedia, “Cognitive Radio”, [Search February 14, 2017], Internet (https://ja.wikipedia.org/wiki/wiki/%E3%82%B3%E3%82%B0%E3% 83% 8B% E3% 83% 86% E3% 82% A3% E3% 83% 96% E7% 84% A1% E7% B7% 9A) Software radio, Hideaki Ogino, Hideaki Odagiri, Kenji Takaro, [Search February 14, 2017], Internet (https://www.oki.com/jp/Home/JIS/Books/KENKAI/n204/pdf/ 204_R20.pdf) NEC develops cognitive radio receiver circuit that utilizes unused frequencies, NEC Green Platform Research Laboratories, [February 14, 2017 search], Internet (http://www.nec.co.jp/press /Ja/1204/images/2001-01-01.pdf)

  However, in cognitive radio that freely uses a frequency band, it is conceivable that a communication terminal that has previously entered the service area preferentially selects and uses a frequency band with good communication quality. Therefore, for example, in areas where people and things are overflowing, there are many communication terminals already communicating, so there is no frequency band where good communication quality can be obtained. Regardless, it may occur in a frequency band where good communication quality cannot be obtained.

  An object of the present invention is to provide a communication device or the like that can improve communication quality even when good communication quality cannot be obtained by selecting a frequency band.

  The communication device of the present invention receives the first radio wave including the second frequency band information representing the second frequency band and the second transmission power information representing the second transmission power, and the second frequency band and the first frequency band A determination unit configured to determine the reception status of the second radio wave transmitted from a communication destination that transmits the second radio wave of the second transmission power, and the determination result by the determination determines the second frequency band and the second A setting unit configured to set transmission power; the second frequency band information indicating the second frequency band for which the setting has been performed; and the second transmission power information indicating the second transmission power for which the setting has been performed. A transmission unit configured to transmit the first wireless radio wave including the first radio wave to the communication destination.

  The communication device or the like of the present invention can improve communication quality even when good communication quality cannot be obtained by selecting a frequency band.

It is a conceptual diagram showing the structural example of the communication system of this embodiment. It is a conceptual diagram showing the structural example of a communication apparatus. It is a conceptual diagram showing the structural example of a communication part. It is a conceptual diagram showing the structural example of a receiving part. It is a conceptual diagram showing the structural example of a transmission part. It is a conceptual diagram showing the process flow example of the process regarding the setting of a transmission frequency band and transmission power. It is FIG. (1) explaining the condition of the communication apparatus of this embodiment. It is FIG. (2) explaining the condition of the communication apparatus of this embodiment. It is an image figure (the 1) showing the received electric field strength in each frequency band. It is FIG. (3) explaining the condition of the communication apparatus of this embodiment. It is an image figure (the 2) showing the received electric field strength in each frequency band. It is an image figure (the 3) showing the received electric field strength in each frequency band. It is an image figure (the 4) showing the received electric field strength in each frequency band. It is an image figure (the 5) showing the received electric field strength in each frequency band. It is an image figure (the 6) showing the received electric field strength in each frequency band. It is FIG. (4) explaining the condition of the communication apparatus of this embodiment. It is an image figure (the 7) showing the received electric field strength in each frequency band. It is an image figure (the 8) showing the received electric field strength in each frequency band. It is an image figure (the 9) showing the received electric field strength in each frequency band. It is an image figure (the 10) showing the received electric field strength in each frequency band. It is an image figure (the 11) showing the received electric field strength in each frequency band. It is a figure showing the time transition of the frequency band which each of the terminals F1-F5 uses for communication. It is a block diagram showing the minimum structure of the communication apparatus of this invention.

[Configuration and operation]
FIG. 1 is a conceptual diagram illustrating a configuration of a communication system 131 that is an example of a communication system according to the present embodiment.

  The communication system 131 includes a communication device 100 and a communication device 901.

  The communication device 100 can change the frequency band of a radio wave that carries transmission information. For example, Patent Literature 3 discloses a technique for changing the frequency of a radio wave.

  The communication device 100 selects a frequency band having a relatively low reception field strength from the frequency distribution of the reception field strength. Then, the communication device 100 transmits the transmission information to the communication device 901 using the first radio wave that is a radio wave in the selected frequency band.

  The communication device 100 also measures the reception status of wireless information carried by the second radio wave that is the radio wave transmitted from the communication device 901. The reception status will be described later with reference to FIG. If the communication device 100 determines that the reception status is not good, the communication device 100 increases the transmission power of the first radio wave.

  In the following description, the transmission power of radio waves used for transmission of radio information is referred to as “transmission power”.

  The communication apparatus 100 includes information indicating the transmission power of the first radio wave in the first radio wave.

  Communication performed by the communication apparatus 100 with a communication apparatus other than the communication apparatus 901 is arbitrary.

  The communication device 901 can receive the wireless information even if the frequency of the radio wave carrying the wireless information sent by the communication device 100 is changed. For example, Non-Patent Document 3 discloses a receiving apparatus that can receive the wireless information even if the frequency of the radio wave is changed.

  The communication device 901 receives the transmission information included in the first radio wave. When the communication device 901 sends transmission information (second transmission information) to the communication device 100, the communication device 901 sets the frequency band of the radio wave (second radio wave) carrying the second transmission information to the first radio. Use the same frequency band as the radio frequency band.

  The communication device 901 also sets the transmission power of the second radio wave from information representing the transmission power of the first radio wave included in the first radio wave. The information representing the transmission power of the first radio wave is, for example, the received electric field strength in the first radio wave communication device 901. Further, the setting is, for example, a setting that increases the transmission power of the second radio wave by one step when the transmission power of the first radio wave increases by one step.

  Communication performed by the communication apparatus 901 with a communication apparatus other than the communication apparatus 100 is arbitrary.

  FIG. 2 is a conceptual diagram illustrating a configuration of a communication apparatus 101 that is an example of the communication apparatus 100 illustrated in FIG. 1.

  The communication apparatus 101 includes a communication unit 106, a processing unit 111, and a recording unit 116.

  The communication unit 106 receives a radio wave reaching the communication unit 106 through a surrounding wireless space by an antenna (not shown) provided in the communication unit 106 and converts the radio wave into an electrical signal.

  When receiving an instruction from the processing unit 111, the communication unit 106 measures the frequency distribution of the received electric field strength that is the electric field strength of the electric signal. This measurement is hereinafter referred to as “scan”. Then, the communication unit 106 sends information representing the frequency distribution of the measured received electric field strength (hereinafter referred to as “scan result”) to the processing unit 111.

  When receiving an instruction from the processing unit 111, the communication unit 106 sets a transmission frequency band and transmission power of a radio wave used for transmission to the communication device 901 illustrated in FIG. 1 according to the instruction. Here, the transmission frequency band and transmission power are the frequency band and transmission power of the radio wave emitted from the communication unit 106 to the radio space.

  When the communication unit 106 sets the transmission frequency band and the transmission power, the radio wave that carries the transmission information transmitted from the processing unit 111 to the communication device 901 illustrated in FIG. Release. The communication unit 106 performs the emission using the transmission frequency band, transmission power, and a predetermined communication method.

  The communication method is not particularly limited as long as it is a wireless communication method. Examples of the communication method include LTE, W-CDMA, CDMA2000, GSM (registered trademark), and wireless LAN. Here, LTE is an abbreviation for Long Term Evolution. W-CDMA is an abbreviation for Wideband Code Division Multiple Access. CDMA2000 is an abbreviation for Code Division Multiple Access 2000. GSM is an abbreviation for global system for mobile communications. LAN is an abbreviation for Local Area Network.

  It is assumed that the radio wave emitted by the communication unit 106 includes information indicating the transmission output level of the radio wave. The information may be the received electric field strength of the radio wave in the communication device 901. The communication device 901 shown in FIG. 1 that has received the radio wave emitted by the communication unit 106 sets the transmission power of the radio wave emitted by the counterpart communication device toward the communication device 101 according to the transmission power.

  For example, when receiving wireless information from a certain communication device, the communication device 901 records a set of the ID (Identifier) of the communication device, the transmission power, and the transmission frequency. The ID may be an address of the communication device. Then, when the destination ID of the wireless information sent by the counterpart communication device is the ID of the communication device 101, the radio wave is transmitted with the transmission power included in the set including the ID that matches the ID of the communication device 101. Output.

  The communication device 901 includes a transmission unit similar to the transmission unit of the communication device 101 described later with reference to FIGS. 3 and 5, so that transmission power can be switched.

  The counterpart communication device includes a transmission unit similar to the transmission unit of the communication device 101 to be described later with reference to FIGS. 3 and 5, so that the frequency band can be switched.

  The communication unit 106 receives information included in the above-described communication method among the above-described electrical signals. The communication unit 106 sends the received information to the processing unit 111.

  When receiving the information, the communication unit 106 acquires reception status information that is information indicating the reception status. The reception status information is, for example, an S / N (signal to noise ratio) or delay time of a received signal. When the communication unit 106 acquires the reception status information, the communication unit 106 sends the reception status information to the processing unit 111.

  The processing unit 111 also instructs the communication unit 106 to perform the scan when starting communication using the communication method. Then, when the scan result is transmitted from the communication unit 106, the processing unit 111 selects a frequency band in which the received radio wave intensity is relatively low in the scan result. However, when the processing unit 111 determines that there is no frequency band in which the received radio wave intensity is relatively low, the processing unit 111 selects an arbitrary frequency band.

  Then, the processing unit 111 instructs the communication unit 106 to transmit transmission information by radio waves in the selected frequency band.

  The processing unit 111 also instructs the communication unit 106 to transmit radio wave power used by the communication unit 106 to transmit transmission information.

  The processing unit 111 determines whether the reception status by the communication apparatus 101 is good at a predetermined timing.

  The processing unit 111 makes the determination, for example, by causing the communication unit 106 to scan again, and in the scan result sent from the communication unit 106, determines whether the received electric field strength in the frequency band set by the communication unit 106 is low. To do.

  Alternatively, the processing unit 111 performs the determination based on, for example, the above-described reception status information (S / N, delay time, etc.).

  If the determination result by the determination indicates that the reception status is not good, the processing unit 111 sets the transmission power of the radio wave to the communication unit 106 within a range that is equal to or lower than a preset upper limit. increase. Thereby, the communication apparatus 101 can perform better information transmission.

  As described above, the communication device 901 illustrated in FIG. 1 increases the transmission power of the radio wave emitted toward the communication device 101 by increasing the transmission power. Therefore, the communication apparatus 101 can receive better information.

  On the other hand, when the determination result of the determination indicates that the reception status is not good and the transmission power of the radio wave cannot be increased due to the upper limit, the processing unit 111 performs scanning again and can perform better reception. Select the band. Then, the processing unit 111 instructs the communication unit 106 to transmit transmission information using radio waves in the selected frequency band.

  The upper limit is set for each application of the communication apparatus 101, for example. In this case, the upper limit is set higher for, for example, the communication device 101 that is considered to have a higher priority for the communication service performed by the communication device 101.

  The upper limit level is, for example, the following four levels depending on the type of communication service.

  Communication services that set the upper limit level to the highest are, for example, disaster prevention radio, air traffic control, emergency vehicles, TV, and radio. These communication services are related to human life or are very public. For this reason, the upper limit level is set to the highest level to enable better communication than other communication services.

  The communication service for setting the upper limit level to the second highest is a communication service used in, for example, a bus or a taxi. These communication services are higher than the above communication services, but are not related to human life or public property, but because the predetermined public property is recognized, it is a second group.

  The communication service for setting the upper limit level to the third highest is, for example, a mobile phone or a public LAN.

  The communication service that sets the upper limit level to the lowest is, for example, amateur radio or short-range communication. The reason why the upper limit level is set to be the lowest is that these communication services have a limited influence when they cannot be used.

  The recording unit 116 holds programs and information necessary for the communication unit 106 and the processing unit 111 to perform the above processing. The recording unit 116 also records information instructed by the communication unit 106 and the processing unit 111. The recording unit 116 also sends the information instructed by the communication unit 106 and the processing unit 111 to the designated destination.

  FIG. 3 is a conceptual diagram illustrating the configuration of the communication unit 106a, which is an example of the communication unit 106 illustrated in FIG.

  The communication unit 106a includes an antenna 201, a transmission unit 206, and a reception unit 211.

  The antenna 201 converts radio waves that have reached the antenna 201 through a wireless space into electrical signals. The antenna 201 sends the converted electrical signal to the receiving unit 211.

  The antenna 201 also converts the transmission power sent from the transmission unit 206 into a transmission radio wave and emits it to the radio space.

  In response to an instruction from the processing unit 111, the reception unit 211 performs the above-described scan on the electrical signal. When the scan is performed, the reception unit 211 sends the scan result to the processing unit 111 illustrated in FIG.

  In addition, when the electrical signal transmitted from the antenna 201 is based on a predetermined communication method, the reception unit 211 performs reception processing on the electrical signal. When the reception unit 211 performs the reception process, the reception unit 211 sends the signal after the reception process to the processing unit 111 illustrated in FIG.

  When the reception unit 211 performs the reception process, the reception unit 211 may acquire the reception status information related to the reception. When the reception unit 211 acquires the reception status information, the reception unit 211 sends the acquired reception status information to the processing unit 111 illustrated in FIG.

  The transmission unit 206 sets the frequency band and transmission power of an electrical signal that the transmission unit 206 sends to the antenna 201 in order to emit a radio wave carrying transmission information in accordance with an instruction from the processing unit 111 shown in FIG. When the transmission unit 206 has set the frequency band and transmission power, the transmission unit 206 transmits the transmission information transmitted from the processing unit 111 according to the set transmission frequency band and transmission power according to the instruction of the processing unit 111. A signal is sent to the antenna 201.

  FIG. 4 is a conceptual diagram illustrating a configuration of a reception unit 211a that is an example of the reception unit 211 illustrated in FIG.

  The reception unit 211a includes a processing unit 301 and a measurement unit 306.

  The measurement unit 306 performs the above-described scan for measuring the frequency distribution of the received electric field strength according to an instruction from the processing unit 111 illustrated in FIG. Then, the measurement unit 306 sends the scan result to the processing unit 111.

  The processing unit 301 performs reception processing on a predetermined electrical signal transmitted from the antenna 201 in accordance with an instruction from the processing unit 111 illustrated in FIG. The reception process is a process of selecting a signal based on a predetermined communication method from the above-described electric signals transmitted from the antenna 201 and acquiring reception information included in the selected electric signal. The processing unit 301 sends the acquired reception information to the processing unit 111.

  FIG. 5 is a conceptual diagram illustrating a configuration of a transmission unit 206a that is an example of the transmission unit 206 illustrated in FIG.

  The transmission unit 206a includes a drive signal generation unit 401, a power adjustment unit 411, and a reference wave generation unit 416.

  The reference wave generation unit 416 sets the frequency of the reference wave signal in response to an instruction from the processing unit 111 illustrated in FIG. Here, the reference wave signal is a carrier wave signal before including transmission information. The reference wave generation unit 416 sends a reference wave signal having a set frequency to the drive signal generation unit 401 in accordance with an instruction from the processing unit 111.

  In accordance with the instruction from the processing unit 111 shown in FIG. 2, the drive signal generation unit 401 generates a carrier signal including transmission information from the transmission information sent from the processing unit 111 and the reference wave signal sent from the reference wave generation unit 416. The transmission wave signal is generated. The transmission wave signal is a transmission wave signal before adjustment of transmission power. The drive signal generation unit 401 sends the generated transmission wave signal to the power adjustment unit 411.

The power adjustment unit 411 amplifies the transmission wave signal sent from the drive signal generation unit 401 in accordance with the instruction from the processing unit 111 shown in FIG. Then, the power adjustment unit 411 sends to the antenna 201 a transmission wave signal in which the transmission power is adjusted to the set transmission power according to an instruction from the processing unit 111 as driving power for causing the antenna 201 to emit radio waves.
[Processing flow example]
FIG. 6 is a conceptual diagram illustrating a processing flow example of processing related to setting of a transmission frequency band and transmission power performed by the processing unit 111 of the communication apparatus 101 illustrated in FIG.

  For example, the processing unit 111 starts the processing illustrated in FIG. 6 by supplying power necessary for the operation from the outside.

  Then, the processing unit 111 instructs the communication unit 106 illustrated in FIG. 2 to perform the scan as the processing of S101. In response to the instruction, the communication unit 106 starts the scan described above.

  Then, the processing unit 111 determines whether the above-described scan result has arrived from the communication unit 106 as the processing of S102.

  The processing unit 111 performs the process of S104 when the determination result of the process of S102 is yes.

  On the other hand, when the determination result of the process of S102 is no, the processing unit 111 performs the process of S102 again.

  When performing the process of S104, the processing unit 111 selects a frequency band in which the received electric field strength is relatively low in the scan result as the same process.

  Then, as the process of S105, the processing unit 111 instructs the communication unit 106 to set the frequency band selected by the process of S104 as the transmission frequency band.

  Then, in step S106, the processing unit 111 instructs the communication unit 106 to set the transmission power W of the radio wave carrying the transmission information to Wmin, which is the minimum power that can be set by the communication unit 106. To do. The transmission power Wmin is transmission power predetermined for the communication apparatus 101.

  Then, as the process of S107, the processing unit 111 instructs the communication unit 106 to start a communication process using the transmission frequency band set by the process of S105 and the transmission power set by the process of S106. Thereafter, when the processing unit 111 sends transmission information to the communication unit 106, the communication unit 106 emits a radio wave including the transmission information toward a wireless space.

  Then, the processing unit 111 determines whether the time ΔT has elapsed as the process of S108. Here, the time ΔT is a time predetermined for the process of S108.

  The processing unit 111 performs the process of S109 when the determination result by the process of S108 is yes.

  On the other hand, when the determination result of the process of S108 is no, the processing unit 111 performs the process of S108 again.

  When performing the process of S109, the processing unit 111 performs the above-described determination as to whether the reception status is good. The processing unit 111 performs the determination by, for example, determining whether the S / N of the received signal is greater than or equal to a reference value.

  The processing unit 111 performs the process of S111 when the determination result of the process of S109 is yes.

  On the other hand, the process part 111 performs the process of S110, when the determination result by the process of S109 is no.

  When performing the process of S110, the processing unit 111 determines whether the value obtained by adding the power ΔW to the set transmission power W is larger than the transmission power Wmax. Here, the power ΔW is power set in advance for the processing of S110 and S112 described later. The transmission power Wmax is a maximum value of transmission power that can be set by the communication unit 106.

  The processing unit 111 performs the process of S111 when the determination result by the process of S110 is yes.

  On the other hand, the process part 111 performs the process of S112, when the determination result by the process of S110 is no.

  When performing the process of S112, the processing unit 111 sets a setting for setting the transmission power W to a value obtained by adding the power ΔW to the transmission power W before the start of the process of S112 to the communication unit 106. Instruct. Then, the processing unit 111 performs the process of S111.

  When performing the process of S111, the processing unit 111 determines whether to end the process illustrated in FIG. 6 as the same process. The processing unit 111 performs the determination by, for example, determining whether or not end information is input from the outside. The end information is, for example, information indicating a stop of supply of externally supplied power.

  If the determination result in S111 is yes, the processing unit 111 ends the process illustrated in FIG.

On the other hand, the process part 111 performs the process of S108 again, when the determination result by S111 is no.
[Concrete example]
Next, a specific example of the operation of the communication apparatus according to this embodiment will be described.

  FIG. 7 is a diagram (part 1) illustrating the state of the communication apparatus according to the present embodiment.

  Terminals F2 and F3 are used on the roadside 512a of the road 511. Further, the terminal F5 is used on the roadside 512b.

  Terminals F2, F3, and F5 are terminals that perform communication using a fixed transmission frequency band and transmission power. The communication frequency bands in the terminals F2, F3, and F5 are the frequency bands f2, f3, and f5 in this order, respectively.

  FIG. 8 is a diagram illustrating a state in which the terminal F4 attempts to start wireless communication on the roadside 512b in the state illustrated in FIG. The terminal F4 receives radio waves when the terminals F2, F3, and F5 perform wireless transmission / reception.

  The terminal F4 is the communication device 101 illustrated in FIG. Terminal F4 can adjust the transmission frequency band and the transmission power. The terminal F4 starts the process shown in FIG. 6 in the state shown in FIG.

  FIG. 9 is a diagram illustrating a result of the scan performed by the terminal F4 illustrated in FIG. 8 (S101 illustrated in FIG. 6) (yes in S102 illustrated in FIG. 6). In addition, in the received electric field strength distribution of each frequency band shown in FIG. 9 and subsequent figures, the received electric field strength distribution for each frequency band is separately shown without being added for easy understanding. In the scan result by the terminal F4, predetermined received electric field strength is detected in the frequency bands f2, f3, and f5. As a result of the scan, it is detected that the received electric field strength is low in the frequency band A.

  Then, the terminal F4 starts transmission of transmission information using the frequency band A shown in FIG. 9 (S104 to S107 shown in FIG. 6).

  As a result, the counterpart communication device (see the communication device 901 shown in FIG. 1) that directly receives the radio wave from the terminal F4 also starts to transmit the radio wave using the frequency band A toward the radio space.

  Therefore, when the terminal F4 performs a scan, for example, a scan result as illustrated in FIG. 10 is obtained. The received electric field strength in the frequency band f4 is due to the counterpart communication device.

  FIG. 11 is a diagram illustrating a state in which the bus 506 subsequently travels on the road 511 in the direction of the arrow 199a. A terminal F1 is mounted on the bus. The terminal F1 is the communication device 101 illustrated in FIG. That is, the terminal F1 can set the transmission frequency band and the transmission power by scanning. The terminal F1 starts the process shown in FIG. 6 in the state shown in FIG.

  FIG. 12 is a diagram illustrating a scan result (yes in S102 of FIG. 6) obtained by scanning the terminal F1 in the state illustrated in FIG.

  Terminal F1 detects from the scan result that the received electric field strength is relatively low in the frequency band near frequency band f4 with which terminal F4 is communicating.

  Then, the terminal F1 starts communication using the frequency band f1 that is a frequency band near the frequency band f4 (S104 to S107 in FIG. 6).

  As a result, the counterpart communication device that directly receives the radio wave from the terminal F1 also starts transmitting the radio wave using the frequency band f1.

  For this reason, when the terminal F1 performs a scan after the start of wireless radio wave transmission, for example, the terminal F1 obtains a scan result as shown in FIG. 13 (yes in S102 of FIG. 6).

  On the other hand, the received electric field strength at the terminal F4 is, for example, as shown in FIG.

  Then, the terminal F4 determines that the reception status in the frequency band f4 is not good due to the influence of the radio wave by the communication performed by the terminal F1 in the frequency band f1 (no in S109 illustrated in FIG. 6).

  Then, the terminal F4 increases the transmission power by the process of S112, but it is still assumed that the reception status does not become good (Yes in S110 shown in FIG. 6).

  Then, the terminal F4 performs the above-described scan again (S101 and S102 shown in FIG. 6).

  The terminal F4 performs communication in the frequency band f4 'that is a frequency band in which the received electric field strength is relatively low (S104 to S107 shown in FIG. 6).

  As a result, the frequency distribution of the received electric field strength at the terminal F4 is as shown in FIG.

  On the other hand, the frequency distribution of the received electric field strength at the terminal F1 is as shown in FIG.

  Thereafter, the bus 506 travels in the direction of the arrow 199a and reaches the position shown in FIG.

  In the state shown in FIG. 17, the terminal F1 is closer to the terminal F4 than the state shown in FIG. For this reason, the received electric field strength at the terminal F1 in the frequency band f4 'increases as shown in FIG. And the reception situation by the frequency band f1 performed by the terminal F1 is not good due to the radio wave of the frequency band f4 'performed by the terminal F4.

  The terminal F1 increases the transmission power to the maximum (S112), but the reception situation does not become good (Yes in S110).

  Therefore, the terminal F1 performs scanning (S101, S102), and performs communication using the frequency band f1 'that has detected that the received electric field strength is relatively weak, as shown in FIG. In FIG. 19, since the communication is not improved only by changing the frequency (no in S109), the transmission power is increased (S112). As a result, the intensity of the radio wave from the counterpart communication device also increases. Yes.

  On the other hand, the terminal F4 is not receiving well due to the influence of the radio wave in the frequency band f1 by the communication performed by the terminal F1 shown in FIG. 20 (no in S109 shown in FIG. 6), and increases the transmission power ( S112). Then, the reception electric field strength from the counterpart communication device has increased, and the frequency band used by the terminal F1 for communication as shown in FIG. 19 is changed from the frequency band f1 to the frequency band f1 ′ (FIG. 21). It is determined that the situation is good (yes in S109).

  Therefore, the terminal F4 does not change the frequency band used for communication until at least the determination result in the process of S109 is next (FIG. 21).

  FIG. 22 is a diagram illustrating a time transition of the frequency band used for communication by each of the terminals F1 to F5 illustrated in FIGS. 11 and 17.

  Time t0 is a certain time before the terminal F1 shown in FIG. 11 starts communication. At time t0, each of the terminals F2 to F5 performs communication in this order in the frequency bands f2, f3, f4, and f5.

  Thereafter, the terminal F1 illustrated in FIG. 11 starts communication using the frequency band f1. The start time is time t1. Thereafter, the terminal F4 detects that the reception state is not good by communication in the frequency band f1 by the terminal F1.

  Then, the terminal F4 illustrated in FIG. 11 changes the frequency band f4 to the frequency band f4 '. The time of the change is time t2.

  Before and after time t3, which is the subsequent time in the state shown in FIG. 11, there is no change in the frequency band used by each terminal for communication.

  As the bus 506 moves, the state shown in FIG. 11 is shifted to the state shown in FIG.

  Before and after time t4, which is the time immediately after the transition to FIG. 16, there is no change in the frequency band used by each terminal for communication. Thereafter, the terminal F1 detects that the reception status is not good due to the influence of the communication in the frequency band f4 performed by the terminal F4 as the bus 506 moves.

  Terminal F1 then changes the frequency band used for communication from frequency band f1 to frequency band f1 '. The time of the change is time t5.

As a result, the good reception status by the frequency band f4 performed in the terminal F4 is kept in an allowable range. Therefore, at the time t6, which is the time after the state shown in FIG. 16, the frequency used for communication is not changed in each terminal including the terminal F4.
[effect]
When the communication apparatus according to the present embodiment detects that the reception situation is not good, first, the electric field strength of the radio wave used for transmission / reception with the counterpart communication apparatus is increased within a predetermined range to improve the reception situation. Plan. If the reception status is not sufficiently improved even if the electric field strength of the radio wave is increased, the communication device performs scanning again, selects a frequency band having a relatively low received electric field strength, and performs communication. Do.

  Therefore, the communication apparatus can ensure higher communication quality as compared with a case where communication is performed by simply selecting a frequency band having a relatively low received electric field strength by scanning.

  FIG. 23 is a block diagram illustrating a configuration of a communication device 101x, which is the minimum configuration of the communication device according to the present embodiment.

  The communication device 101x includes a transmission unit 206x, a setting unit 302x, and a determination unit 301x.

  The determination unit 301x determines the reception status of the second radio wave transmitted from a communication destination (not shown). When the communication destination receives the first radio wave including the second frequency band information representing the second frequency band and the second transmission power information representing the second transmission power, the second frequency band and the second transmission The second radio wave of power is transmitted.

  The setting unit 302x sets the second frequency band and the second transmission power based on the determination result by the determination.

  The transmission unit 206x includes the first radio including the second frequency band information indicating the second frequency band for which the setting has been performed and the second transmission power information indicating the second transmission power for which the setting has been performed. Radio waves are transmitted to the communication destination. The communication device 101x not only selects the frequency band of the second radio wave sent by the communication destination from the received electric field strength of the second radio wave, but also if the reception situation is not good, the second radio wave Adjust the transmission power. Therefore, even if the reception status of the second radio wave is not sufficiently improved by the selection of the frequency band, the communication device 101x can adjust the second transmission power to adjust the reception status of the second radio wave. Improvements can be made.

  Therefore, the communication apparatus 101x has the effects described in the section [Effects of the Invention] by the above configuration.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and further modifications, substitutions, and adjustments may be made without departing from the basic technical idea of the present invention. Can be added. For example, the configuration of the elements shown in each drawing is an example for helping understanding of the present invention, and is not limited to the configuration shown in these drawings.

  Further, a part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix A1)
When the first radio wave including the second frequency band information representing the second frequency band and the second transmission power information representing the second transmission power is received, the second radio of the second frequency band and the second transmission power A determination unit configured to determine the reception status of the second radio wave transmitted from a communication destination that transmits radio waves;
A setting unit configured to set the second frequency band and the second transmission power according to the determination result by the determination;
The first radio wave including the second frequency band information representing the second frequency band for which the setting has been performed and the second transmission power information representing the second transmission power for which the setting has been performed, Send first, send part,
A communication device comprising:

(Appendix A2)
The communication apparatus according to appendix A1, wherein the second transmission power information is a second received electric field strength that is a received electric field strength at the communication destination of the first radio wave.

(Appendix A3)
The communication device according to appendix A1 or appendix A2, wherein the second frequency band information is a first frequency band that is a frequency band of the first radio wave.

(Appendix A4)
The communication device according to attachment A3, wherein the first frequency band and the second frequency band are equal.

(Appendix A5)
The setting of the second frequency band is performed from a frequency range in which the first received electric field strength is relatively low in the frequency distribution of the first received electric field strength that is the received electric field strength of the second radio wave. The communication device described in any one of Appendix A4.

(Appendix A6)
The communication apparatus according to any one of Supplementary Notes A1 to A5, wherein the setting of the second transmission power is performed within a predetermined range.

(Appendix A7)
The communication device according to attachment A6, wherein an upper limit of the range is determined for each communication service to be used.

(Appendix A8)
The communication device according to attachment A7, wherein the upper limit is higher for the communication service having higher publicity.

(Appendix A9)
The communication device according to appendix A7 or appendix A8, wherein the communication service with the highest upper limit includes at least one of disaster prevention radio, air traffic control, emergency vehicle, TV, and radio.

(Appendix A10)
The communication device according to any one of supplementary notes A7 to A9, wherein the setting of the second frequency band is performed when the second transmission power is the upper limit or in the vicinity of the upper limit.

(Appendix B1)
A communication system comprising the communication device according to any one of Supplementary Notes A1 to A10 and the communication destination.

(Appendix B2)
The communication system according to appendix B1, comprising a plurality of the second communication devices.

(Appendix C1)
When the first radio wave including the second frequency band information representing the second frequency band and the second transmission power information representing the second transmission power is received, the second radio of the second frequency band and the second transmission power Perform a determination on the reception status of the second radio wave sent from the communication destination that transmits the radio wave,
According to the determination result by the determination, the second frequency band and the second transmission power are set.
The first radio wave including the second frequency band information representing the second frequency band for which the setting has been performed and the second transmission power information representing the second transmission power for which the setting has been performed, Send first,
Communication method.

(Appendix D1)
When the first radio wave including the second frequency band information representing the second frequency band and the second transmission power information representing the second transmission power is received, the second radio of the second frequency band and the second transmission power Processing for determining the reception status of the second radio wave sent from a communication destination that transmits radio waves;
A process for setting the second frequency band and the second transmission power according to the determination result by the determination;
The first radio wave including the second frequency band information representing the second frequency band for which the setting has been performed and the second transmission power information representing the second transmission power for which the setting has been performed, Processing to send first,
A communication program that causes a computer to execute.

100, 101, 101x, 901 Communication device 106, 106a Communication unit 111 Processing unit 116 Recording unit 131 Communication system 199a Arrow 201 Antenna 206, 206a, 206x Transmission unit 211, 211a Reception unit 301 Processing unit 301x Determination unit 306 Measurement unit 401 Drive Signal generation unit 411 Power adjustment unit 416 Reference wave generation unit 511 Road 506 Bus 512a, 512b Roadside A Frequency band f1, f1 ′, f2, f3, f4, f4 ′, f5 Frequency band F1, F2, F3, F4, F5 Terminal

Claims (10)

When the first radio wave including the second frequency band information representing the second frequency band and the second transmission power information representing the second transmission power is received, the second radio of the second frequency band and the second transmission power A determination unit configured to determine the reception status of the second radio wave transmitted from a communication destination that transmits radio waves;
A setting unit configured to set the second frequency band and the second transmission power according to the determination result by the determination;
The first radio wave including the second frequency band information representing the second frequency band for which the setting has been performed and the second transmission power information representing the second transmission power for which the setting has been performed, Send first, send part,
A communication device comprising:   The communication apparatus according to claim 1, wherein the second transmission power information is a second received electric field strength that is a received electric field strength at the communication destination of the first radio wave.   The communication apparatus according to claim 1, wherein the second frequency band information is a first frequency band that is a frequency band of the first radio wave.   The communication device according to claim 1, wherein the first frequency band and the second frequency band are equal.   2. The setting of the second frequency band is performed from a frequency range in which the first received electric field strength is relatively low in a frequency distribution of the first received electric field strength that is the received electric field strength of the second radio wave. The communication apparatus as described in any one of thru | or 4 thru | or 4.   The communication apparatus according to any one of claims 1 to 5, wherein the setting of the second transmission power is performed within a predetermined range.   The communication apparatus according to claim 6, wherein an upper limit of the range is determined for each communication service to be used.   The communication apparatus according to claim 7, wherein the upper limit is higher for the communication service having higher publicity.   The communication device according to claim 7 or 8, wherein the communication service with the highest upper limit includes at least one of disaster prevention radio, air traffic control, emergency vehicle, TV, and radio.   The communication according to any one of claims 7 to 9, wherein the setting of the second frequency band is performed when the second transmission power is the upper limit or in the vicinity of the upper limit. apparatus.

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