JP2015056762A - Communication apparatus, communication method, and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve communication efficiency in radio communication.SOLUTION: A communication apparatus has: a use channel selection section for selecting combinations of a plurality of channels to be used for communication; a communication section for communicating with other communication apparatuses using the selected channel; and a transmission signal generation section for generating a transmission signal for transmitting information on the selected channel. The transmission signal generation section, when generating the transmission signal, stores the information on the selected channel in a sub-carrier which is not used for transmitting transmission data.

Description

  The present invention relates to a technique for improving communication efficiency.

  Conventionally, IEEE802.11a and IEEE802.11n are used as a standard of a wireless LAN (Local Area Network) using a 5 GHz band. In IEEE 802.11a, wireless communication is performed using a frequency band of 20 MHz per channel. In IEEE802.11n, channel bonding is proposed as a technique for performing communication using two adjacent channels simultaneously. As a result, the wireless LAN access point (hereinafter referred to as “AP”) can use the frequency band of two channels (40 MHz), thereby realizing high-speed communication.

  In recent years, IEEE 802.11ac that can theoretically transmit at 1 Gbps or more has been proposed as a next-generation communication standard of IEEE 802.11n (see, for example, Patent Document 1). In IEEE802.11ac, the AP can use a frequency band corresponding to eight channels (maximum 160 MHz) by channel bonding, so that communication speed can be further increased than that of IEEE802.11n.

JP 2012-70090 A

  However, when the AP performs communication using the frequency band of 160 MHz by channel bonding, if each channel of the frequency band used by the AP is used by another AP, the AP and the other AP There is a risk that communication opportunities will overlap. When communication opportunities overlap, data collision occurs between the AP and another AP. Therefore, the AP performs CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) in order to avoid data collision with other APs. Specifically, the AP detects whether or not another AP is communicating, and when the other AP is communicating, it does not transmit data and the other AP is communicating. If not, send the data. Thereby, data collision between the AP and another AP can be avoided. However, the AP may not be able to perform communication using the entire frequency band of 160 MHz. That is, the AP may only be able to communicate using a frequency band of 60 MHz or 40 MHz. In the worst case, even communication may not be possible. When such a problem occurs, the AP cannot efficiently use the frequency band used by channel bonding. Therefore, there has been a problem that communication efficiency in AP wireless communication is reduced.

  In view of the above circumstances, an object of the present invention is to provide a technique for improving communication efficiency in wireless communication.

  One embodiment of the present invention includes a use channel selection unit that selects a combination of a plurality of channels used for communication, a communication unit that communicates with another communication device using the selected channel, A transmission signal generation unit that generates a transmission signal for transmitting information, and the transmission signal generation unit converts the information of the selected channel into transmission data when generating the transmission signal. It is a communication device for storing in subcarriers that are not used.

  One aspect of the present invention is the communication apparatus described above, wherein the use channel selection unit selects a channel to be used in order from a combination of the plurality of channels in order from a channel having a small influence on the own apparatus.

  One aspect of the present invention is a usage channel selection step of selecting a combination of a plurality of channels used for communication, a communication step of communicating with another communication device using the selected channel, A transmission signal generation step for generating a transmission signal for transmitting information, and when the transmission signal is generated in the transmission signal generation step, the information on the selected channel is used for transmission of transmission data. This is a communication method for storing in unused subcarriers.

  One aspect of the present invention is a usage channel selection step of selecting a combination of a plurality of channels used for communication, a communication step of communicating with another communication device using the selected channel, A transmission signal generation step for generating a transmission signal for transmitting information, and when the transmission signal is generated in the transmission signal generation step, information on the selected channel is transmitted as transmission data. It is a computer program stored in a subcarrier that is not used in the system.

  According to the present invention, communication efficiency in wireless communication can be improved.

It is a block diagram which shows the system configuration | structure of the radio | wireless communications system in 1st Embodiment of this invention. It is a block diagram of a channel information database. It is the schematic which shows the specific example of a utilization channel notification method. It is a flowchart which shows the flow of the utilization channel notification method in 1st Embodiment of this invention. It is a flowchart which shows the flow of the use band selection process in 1st Embodiment of this invention. FIG. 3 is a sequence diagram showing an operation of the wireless communication system in the first embodiment of the present invention. It is a block diagram which shows the system configuration | structure of the radio | wireless communications system in 2nd Embodiment of this invention. It is a sequence diagram which shows operation | movement of the radio | wireless communications system in 2nd Embodiment of this invention. It is a figure which shows the specific example to which the radio | wireless communications system of this invention is applied.

Hereinafter, specific configuration examples (first embodiment and second embodiment) of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing a system configuration of a radio communication system according to the first embodiment of the present invention. The wireless communication system according to the first embodiment includes an HGW (Home GateWay) 10a and a communication terminal 20a. 1 shows a configuration in which the wireless communication system includes one HGW 10a, the wireless communication system may be configured to include two or more HGWs 10a. 1 shows a configuration in which the wireless communication system includes one communication terminal 20a, the wireless communication system may be configured to include two or more communication terminals 20a.

  The HGW 10a is a wireless LAN access point, and connects the communication terminal 20a connected to the own device (HGW 10a) to a network (not shown), for example, access to a server device (not shown) via the network. provide. The HGW 10a can communicate with the communication terminal 20a using a plurality of channels at the same time. The HGW 10a communicates with the communication terminal 20a by a multicarrier transmission method (for example, OFDM (Orthogonal Frequency Division Multiplexing)).

  The communication terminal 20a is configured using an information processing device such as a personal computer, a tablet device, a smartphone, a notebook computer, a workstation, a game device, a videophone device, or the like. The communication terminal 20a can communicate with the HGW 10a simultaneously using a plurality of channels. Further, the communication terminal 20a communicates with the HGW 10a by a multicarrier transmission method (for example, OFDM).

  Hereinafter, specific configurations of the HGW 10a and the communication terminal 20a will be described. First, the functional configuration of the HGW 10a will be described. The HGW 10a includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and executes a wireless communication program. By executing the wireless communication program, the HGW 10 a functions as an apparatus including the communication unit 101, the channel scan unit 102, the channel information storage unit 103, the determination unit 104, the use channel selection unit 105, and the transmission signal generation unit 106. All or some of the functions of the HGW 10a may be realized using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA). The wireless communication program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system. The wireless communication program may be transmitted / received via an electric communication line.

The communication unit 101 communicates with the communication terminal 20a. For example, the communication unit 101 communicates with the communication terminal 20a using a plurality of channels at the same time.
The channel scanning unit 102 periodically performs carrier sense for detecting whether or not another communication device (for example, another HGW or the communication terminal 20a) is performing communication for all channels. For example, when another communication device is communicating, the channel scanning unit 102 detects the other communication device by receiving a beacon or a packet.

  The channel information storage unit 103 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The channel information storage unit 103 stores a channel information database. Hereinafter, the channel information database will be described with reference to FIG. FIG. 2 is a configuration diagram of a channel information database stored in the channel information storage unit 103. The channel information database has a plurality of records 30 relating to channel information. The record 30 has channel and SSID number values. The channel value represents the channel from which the channel information represented by the record 30 has been acquired. The value of the number of SSIDs represents the number of SSIDs (Service Set Identifiers) of other relay apparatuses (for example, access points) that are using the channel from which the channel information represented by the record 30 is acquired.

  In the example shown in FIG. 2, there are a plurality of channels (36 ch to 64 ch, 100 ch to 140 ch) in the channel information database. In FIG. 2, the uppermost row of the channel information database has a channel value “36” and an SSID count value “1”. That is, the number of other relay apparatuses using “36ch” is “1”. In the present embodiment, since the number of SSIDs is based on the premise that the SSIDs are set to different SSIDs, the number of SSIDs is the number of relay devices.

Returning to FIG. 1, the description of the HGW 10a will be continued.
The determination unit 104 determines whether each channel is a usable channel based on the channel information database stored in the channel information storage unit 103. For example, the determination unit 104 determines whether each channel is an available channel based on the number of SSIDs of each channel in the channel information database. More specifically, when the number of SSIDs is equal to or greater than the threshold, the determination unit 104 determines that the channel having the number of SSIDs equal to or greater than the threshold is not a usable channel. On the other hand, when the number of SSIDs is less than the threshold, the determination unit 104 determines that a channel having the number of SSIDs less than the threshold is a usable channel.

  An available channel represents a channel that is unlikely to affect the communication of the own device even when another communication device is communicating. That is, when there is a channel whose number of SSIDs is equal to or greater than the threshold, the number of other communication devices using the channel is large. Therefore, there is a high risk of affecting the communication of the own device. As a result, there is a high possibility that the HGW 10a cannot communicate. On the other hand, when there is a channel whose number of SSIDs is less than the threshold, the number of other communication apparatuses using the channel is small. Therefore, there is a low risk of affecting the communication of the own device. As a result, there is a low possibility that the HGW 10a cannot communicate. Based on the determination criteria described above, the determination unit 104 determines for each channel whether the channel is an available channel. The determination unit 104 outputs information indicating a determination result for each channel (hereinafter referred to as “channel usage information”) to the usage channel selection unit 105.

  Based on the output channel usage information and the channel information database stored in the channel information storage unit 103, the usage channel selection unit 105 uses a channel (hereinafter referred to as “usage channel”) used by the own device (HGW 10a) for communication. Select). Specifically, first, the use channel selection unit 105 identifies the number of channels determined to be usable based on the channel use information. Next, the use channel selection unit 105 selects a frequency bandwidth (hereinafter referred to as “use band”) to be used for communication according to the specified number of channels of available channels. Thereafter, the use channel selection unit 105 refers to the channel information database and selects a use channel to be used in the selected use band from available channels. For example, the use channel selection unit 105 selects a use channel in the order of the available channels and the few SSIDs.

  The transmission signal generation unit 106 generates a transmission signal using information on the usage channel selected by the usage channel selection unit 105. Specifically, the transmission signal generation unit 106 performs modulation processing (for example, serial / parallel conversion, subcarrier modulation, IFFT (Inverse Fast Fourier Transform), parallel / serial conversion, guard interval insertion on transmission data to be transmitted. Etc.) to generate a transmission signal. At this time, the transmission signal generation unit 106 uses the information of the utilization channel as a central subcarrier (hereinafter referred to as subcarrier number 0) that is not used in OFDM (not used for transmission of pilot signals and data) among a plurality of subcarriers. , Referred to as “central subcarrier”). Here, storing in the center subcarrier (subcarrier not used for transmission of transmission data) means transmitting data on the subcarrier.

  Next, the functional configuration of the communication terminal 20a will be described. The communication terminal 20a includes a CPU, a memory, an auxiliary storage device, and the like connected by a bus, and executes a wireless communication program. By executing the wireless communication program, the communication terminal 20a functions as an apparatus including the communication unit 201, the signal processing unit 202, the use channel selection unit 203, and the transmission signal generation unit 204. All or some of the functions of the communication terminal 20a may be realized using hardware such as an ASIC, PLD, or FPGA. The wireless communication program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system. The wireless communication program may be transmitted / received via an electric communication line.

The communication unit 201 communicates with the HGW 10a. The communication unit 201 communicates with the HGW 10a using, for example, a plurality of channels at the same time. The communication unit 201 receives a transmission signal from the HGW 10a.
The signal processing unit 202 demodulates the signal for each subcarrier by performing demodulation processing (eg, guard interval removal, serial / parallel conversion, FFT, etc.) on the received transmission signal. Thereafter, the signal processing unit 202 acquires information on the used channel from the center subcarrier (subcarrier of subcarrier number 0). The signal processing unit 202 outputs the acquired usage channel information to the usage channel selection unit 203.
The usage channel selection unit 203 selects the usage channel of the own device (communication terminal 20a) based on the output usage channel information.
The transmission signal generation unit 204 generates a transmission signal by performing modulation processing on transmission data to be transmitted.

FIG. 3 is a schematic diagram illustrating a specific example of the usage channel notification method.
FIG. 3A is a diagram showing a specific example of the usage status of each channel. FIG. 3A shows that 36 ch, 44 ch to 52 ch, 60 ch, 64 ch, 104 ch, 108 ch, 116 ch, 128 ch, and 136 ch are used. Therefore, there are eight channels (empty channels) that can be used for communication between the HGW 10a and the communication device 20a: 40 ch, 56 ch, 100 ch, 112 ch, 120 ch, 124 ch, 132 ch, and 140 ch. In this case, the use channel selection unit 105 selects, as the next use channel, a channel that is unlikely to affect the own device (HGW 10a) from the above-described available channels (for example, 8 channels). For example, the use channel selection unit 105 refers to the channel information database, and selects use channels in the order of available channels and the smallest number of SSIDs. The usage channel selection process will be described below with a specific example.

In the following description, a case will be described in which 100 ch is set as the primary channel in the HGW 10a, and the number of SSIDs is small in ascending order of channel numbers of available channels.
First, the use channel selection unit 105 selects 40 ch as a next use channel. Next, when the HGW 10a uses 40ch, the use channel selection unit 105 selects 56ch as the next channel to be used. When using 56 ch, the use channel selection unit 105 selects 112 ch as the next channel to be used. At this time, although 100 ch exists as a channel that can be used before 112 ch, since 100 ch has been used once as the primary channel of the HGW 10a, the used channel selection unit 105 selects the 112 ch that is not yet used as the next channel to be used. To do. Thereafter, when the channel 112 is used, the used channel selection unit 105 selects 120 ch as the next channel to be used. When using 120 ch, the use channel selection unit 105 selects 124 ch as the next channel to be used. When using 124 ch, the use channel selection unit 105 selects 132 ch as the next channel to be used. When using 132 ch, the use channel selection unit 105 selects 140 ch as the next channel to be used. The use channel selection unit 105 does not select a use channel because there is no next use channel when 140 ch is used. In this way, the use channel selection unit 105 selects a channel to be used between the HGW 10a and the communication terminal 20a. This is the end of the description of the usage channel selection process.

  FIG. 3B is a diagram illustrating a transmission signal generated by the transmission signal generation unit 106. Each peak of the transmission signal shown in FIG. 3B is a subcarrier. That is, the transmission signal generated by the transmission signal generation unit 106 includes a plurality of subcarriers. The subcarriers of the transmission signal are 53 from subcarrier number “−26” to subcarrier number “26” before and after subcarrier 40 (center subcarrier) located at the center of a plurality of subcarriers, with subcarrier number 0. It is composed of subcarriers. When the transmission signal generator 106 generates a transmission signal, the transmission signal generator 106 stores information on the used channel in the subcarrier 40. In the specific example described above, the transmission signal generation unit 106 generates a transmission signal by storing information on a channel to be used next (for example, 40 ch) in the subcarrier 40. Thereafter, the HGW 10a transmits the generated transmission signal to the communication terminal 20a. When the reception confirmation signal is received, the transmission signal generation unit 106 generates a transmission signal by storing information on a channel to be used next (for example, 56 ch) in the subcarrier 40 by using 40 ch next. . Thereafter, the HGW 10a transmits the generated transmission signal to the communication terminal 20a. When such processing is repeatedly executed and the transmission signal generation unit 106 uses 140 ch, there is no channel to be used next. Therefore, the transmission signal generation unit 106 generates a transmission signal by storing information indicating that the use channel notification is ended in the subcarrier 40. Thereafter, the HGW 10a transmits the generated transmission signal to the communication terminal 20a. By performing the above-described processing, a channel used for communication is notified between the HGW 10a and the communication terminal 20a. Then, communication is performed using the channel used between the HGW 10a and the communication terminal 20a, so that an available channel can be used efficiently.

FIG. 4 is a flowchart showing the flow of the usage channel notification method in the first embodiment of the present invention.
The channel scan unit 102 performs carrier sense on all channels by periodically performing channel scan (step S101). The channel scan unit 102 updates the SSID value for each channel acquired by carrier sense by overwriting the SSID value for each channel recorded in the channel information database (step S102).

  Next, the usage channel selection unit 105 acquires channel usage information from the determination unit 104 (step S103). Specifically, the determination unit 104 determines whether each channel is an available channel based on the updated channel information database. Then, when the determination of each channel is completed, the determination unit 104 outputs channel usage information based on the determination result to the usage channel selection unit 105. The use channel selection unit 105 acquires the channel use information output from the counter unit 104. Next, the use channel selection unit 4105 selects a use band based on the output channel use information (step S104). In addition, the use band selection process which the use channel selection part 105 performs as a process of step S104 is mentioned later.

  The use channel selection unit 105 selects a use channel based on the channel information database and the selected use band (step S105). The transmission signal generation unit 106 generates a transmission signal by storing information on the selected usage channel in the central subcarrier (step S106). The communication unit 101 transmits the generated transmission signal to the communication terminal 20a (step S107). Thereafter, the HGW 10a and the communication terminal 20a communicate using the use channel (step S108).

FIG. 5 is a flowchart showing the flow of the used band selection process in the first embodiment of the present invention.
The use channel selection unit 105 determines whether there are eight or more channels that can be used based on the channel use information (step S201). When there are eight or more channels that can be used (YES in step S201), the used channel selection unit 105 selects a band for 160 MHz as a use band (step S202). At this time, if the number of available channels is 8, the used channel selection unit 105 selects all eight channels as used channels in the process of step S105 of FIG. When the number of usable channels is 9 or more, the used channel selection unit 105 refers to the channel information database in the process of step S105 in FIG. Select a channel to be used. When there are a plurality of usable channels with the same number of SSIDs, a usable channel is selected at random from available channels with the same number of SSIDs. On the other hand, when the number of available channels is less than 8 (step S201—YES), the used channel selection unit 105 determines whether there are 4 to 7 available channels (step S203).

  When the number of channels that can be used is 4 to 7 (step S203—YES), the used channel selection unit 105 selects a band for 80 MHz as a use band (step S204). At this time, if the number of available channels is 4, the used channel selection unit 105 selects all four channels as used channels in the process of step S105 in FIG. When the number of usable channels is 5 to 7, the used channel selection unit 105 refers to the channel information database in the process of step S105 in FIG. Channels are selected as usage channels. On the other hand, when the number of available channels is not 4 to 7 (step S203—NO), the used channel selection unit 105 determines whether or not the number of available channels is 2 to 3 (step S205). .

  When the number of available channels is 2 to 3 (YES in step S205), the used channel selection unit 105 selects a band for 40 MHz as a used band (step S206). At this time, if the number of channels that can be used is two, the channel selection unit 105 selects all two channels as channels to be used in step S105 of FIG. When the number of available channels is 3, the used channel selection unit 105 refers to the channel information database in the process of step S105 in FIG. Select a channel as a usage channel. On the other hand, when the number of available channels is not 2 to 3 (NO in step S205), the used channel selection unit 105 determines whether or not the number of available channels is 1 (step S207). When the number of available channels is 1 (step S207—YES), the used channel selection unit 105 selects a band for 20 MHz as a use band (step S208). On the other hand, when the number of usable channels is 0 (step S207—NO), the used channel selection unit 105 selects a band corresponding to 20 MHz as a use band (step S209). The band selected at this time is the band of the primary channel used by the HGW 10a.

FIG. 6 is a sequence diagram showing an operation of the wireless communication system in the first embodiment of the present invention.
The channel scanning unit 102 of the HGW 10a performs carrier sensing for all channels by periodically performing channel scanning (step S301). The channel scan unit 102 updates the channel information database stored in the channel information storage unit 103 based on the carrier sense result (step S302). The determination unit 104 refers to the channel information database and determines whether each channel is an available channel (step S303). When the determination for each channel is completed, the determination unit 104 outputs the channel usage information to the usage channel selection unit 105. The use channel selection unit 105 selects a use band based on the output channel use information (step S304). Next, the use channel selection unit 105 selects a use channel based on the channel information database and the selected use band (step S305).

The transmission signal generation unit 106 generates a transmission signal based on the usage channel selected by the usage channel selection unit 105 (step S306). Specifically, when generating a transmission signal, transmission signal generation section 106 stores information on the used channel in the central subcarrier. Thereafter, the communication unit 101 transmits the generated transmission signal to the communication terminal 20a (step S307).
The communication unit 201 of the communication terminal 20a receives a transmission signal from the HGW 10a (step S308). Thereafter, the communication unit 201 generates a reception confirmation signal (ACK signal) indicating that the transmission signal has been received, and transmits the reception confirmation signal to the HGW 10a (step S309). Thereafter, the signal processing unit 202 demodulates the signal for each subcarrier by performing demodulation processing on the received transmission signal. The signal processing unit 202 acquires information on the used channel from the central subcarrier (step S310). The signal processing unit 202 outputs the acquired usage channel information to the usage channel selection unit 203. The usage channel selection unit 203 selects a usage channel of the own device (communication terminal 20a) based on the output usage channel information (step S311). Thereafter, the HGW 10a and the communication terminal 20a communicate using the use channel (step S312). Thereafter, the processing from step S301 to step S312 is repeatedly executed.

  According to the wireless communication system configured as described above, channel information used for channel bonding can be notified to the communication terminal 20a. Specifically, when the transmission signal generation unit 106 of the HGW 10a generates a transmission signal, information on the used channel is stored in the central subcarrier. Then, the HGW 10a transmits the generated transmission signal to the communication terminal 20a. The communication terminal 20a can grasp which channel is used for communication by acquiring information on the used channel stored in the central subcarrier of the received transmission signal. Thereafter, communication is performed between the HGW 10a and the communication terminal 20a using a use channel. Therefore, the available channels can be used efficiently. Therefore, communication efficiency in wireless communication can be improved.

<Modification>
In the channel information database, the number of communication terminals (number of STAs) using each channel may be recorded instead of the number of SSIDs. In this case, the value of the number of STAs represents the number of communication terminals belonging to other relay apparatuses using the channel for which the channel information represented by the record 30 is acquired. Then, when the number of STAs for each channel is equal to or greater than the threshold, the determination unit 104 determines that a channel that is equal to or greater than the threshold is not a usable channel. On the other hand, when the number of STAs for each channel is less than the threshold, the determination unit 104 determines that the channel that is less than the threshold is a usable channel.
Information on a plurality of usage channels may be assigned to the center subcarrier.
The usage channel selection method is not limited to the above-described method, and may be selected according to a predetermined rule. For example, a use channel may be selected from channels that can be used in ascending order of channel numbers. For example, as shown in FIG. 3A, when eight channels of 40 ch, 56 ch, 100 ch, 112 ch, 120 ch, 124 ch, 132 ch, and 140 ch are usable channels, the used channel selection unit 105 first sets 40 ch. Select the channel to be used, and select 56ch as the next channel to be used. Then, the use channel selection unit 105 selects a use channel from the channels that can be used in ascending order of channel numbers, and finally 140 ch is selected as the use channel.

[Second Embodiment]
FIG. 7 is a block diagram showing a system configuration of a radio communication system according to the second embodiment of the present invention. The wireless communication system of the present invention includes an HGW 10b and a communication terminal 20b. 7 shows a configuration in which the wireless communication system includes one HGW 10b, the wireless communication system may be configured to include two or more HGWs 10b. 7 shows a configuration in which the wireless communication system includes one communication terminal 20b, the wireless communication system may be configured to include two or more communication terminals 20b.

  Hereinafter, specific configurations of the HGW 10b and the communication terminal 20b will be described. First, the functional configuration of the HGW 10b will be described. The HGW 10b includes a CPU, a memory, an auxiliary storage device, and the like connected by a bus, and executes a wireless communication program. By executing the wireless communication program, the HGW 10b functions as an apparatus including the communication unit 101, the channel scan unit 102, the channel information storage unit 103, the determination unit 104, the used channel selection unit 105, the transmission signal generation unit 106, and the signal processing unit 107. To do. Note that all or part of the functions of the HGW 10b may be realized using hardware such as an ASIC, PLD, or FPGA. The wireless communication program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system. The wireless communication program may be transmitted / received via an electric communication line.

The HGW 10b is different from the HGW 10a in that the signal processing unit 107 is provided instead of the channel scanning unit 102, the channel information storage unit 103, and the determination unit 104. The HGW 10b is the same as the HGW 10a in other configurations. Therefore, description of the entire HGW 10b is omitted, and the signal processing unit 107 will be described.
The signal processing unit 107 demodulates the signal for each subcarrier by performing demodulation processing (eg, guard interval removal, serial / parallel conversion, FFT, etc.) on the received transmission signal. After that, the signal processing unit 107 acquires information on the used channel from the center subcarrier (subcarrier of subcarrier number 0). The signal processing unit 107 outputs the acquired usage channel information to the usage channel selection unit 105. In this case, the usage channel of the own device (HGW 10b) is selected based on the output usage channel information.

  Next, the functional configuration of the communication terminal 20b will be described. The communication terminal 20b includes a CPU, a memory, an auxiliary storage device, and the like connected by a bus, and executes a wireless communication program. By executing the wireless communication program, the communication terminal 20b functions as an apparatus including the communication unit 201, the used channel selection unit 203, the transmission signal generation unit 204, the channel scan unit 205, the channel information storage unit 206, and the determination unit 207. Note that all or some of the functions of the communication terminal 20b may be realized using hardware such as an ASIC, PLD, or FPGA. The wireless communication program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system. The wireless communication program may be transmitted / received via an electric communication line.

  The communication terminal 20b is different from the communication terminal 20a in that the communication terminal 20b includes a channel scan unit 205, a channel information storage unit 206, and a determination unit 207 instead of the signal processing unit 202. The communication terminal 20b is the same as the communication terminal 20a in other configurations. Therefore, description of the communication terminal 20b as a whole is omitted, and the channel scan unit 205, the channel information storage unit 206, and the determination unit 207 will be described.

The channel scanning unit 205 periodically performs carrier sense to detect whether another communication device (for example, another communication terminal or the HGW 10b) is communicating with all channels. For example, when another communication device is communicating, the channel scan unit 205 detects the other communication device by receiving a beacon or a packet.
The channel information storage unit 206 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The channel information storage unit 206 stores a channel information database. The configuration of the channel information database is the same as that of the channel information database in FIG.
The determination unit 207 determines whether each channel is an available channel based on the channel information database stored in the channel information storage unit 206. As a result of the determination, the determination unit 207 outputs the channel usage information to the usage channel selection unit 203.

In this case, the use channel selection unit 203 and the transmission signal generation unit 204 operate as follows. The use channel selection unit 203 selects the use channel of the own device (communication terminal 20b) based on the output channel use information and the channel information database stored in the channel information storage unit 206.
The transmission signal generation unit 204 generates a transmission signal using information on the usage channel selected by the usage channel selection unit 203. Specifically, the transmission signal generation unit 204 performs modulation processing (for example, serial / parallel conversion, subcarrier modulation, IFFT (Inverse Fast Fourier Transform), parallel / serial conversion, and guard interval insertion on transmission data to be transmitted. Etc.) to generate a transmission signal. At this time, the transmission signal generation unit 204 stores information on the used channel in the central subcarrier.

FIG. 8 is a sequence diagram showing an operation of the wireless communication system in the second embodiment of the present invention.
The channel scanning unit 205 of the communication terminal 20b performs carrier sensing for all channels by periodically performing channel scanning (step S401). The channel scan unit 205 updates the channel information database stored in the channel information storage unit 206 based on the carrier sense result (step S402). The determination unit 207 refers to the channel information database to determine whether each channel is an available channel (step S403). When the determination of each channel is completed, the determination unit 207 outputs the channel usage information to the usage channel selection unit 203. The use channel selection unit 203 selects a use band based on the output channel use information (step S404). Next, the use channel selection unit 203 selects a use channel based on the channel information database and the selected use band (step S405).

The transmission signal generation unit 204 generates a transmission signal based on the usage channel selected by the usage channel selection unit 203 (step S406). Specifically, when generating a transmission signal, the transmission signal generation unit 204 stores information on the used channel in the central subcarrier. Thereafter, the communication unit 201 transmits the generated transmission signal to the HGW 10b (step S407).
The communication unit 101 of the HGW 10b receives a transmission signal from the communication terminal 20b (step S408). Thereafter, the communication unit 101 generates a reception confirmation signal indicating that the transmission signal has been received, and transmits the reception confirmation signal to the communication terminal 20b (step S409). Thereafter, the signal processing unit 107 demodulates the signal for each subcarrier by performing demodulation processing on the received transmission signal. The signal processing unit 107 acquires information on the used channel from the central subcarrier (step S410). The signal processing unit 107 outputs the acquired usage channel information to the usage channel selection unit 105. The usage channel selection unit 105 selects a usage channel of the own device (HGW 10b) based on the output usage channel information (step S411). Thereafter, the HGW 10b and the communication terminal 20b communicate using the use channel (step S412). Thereafter, the processing from step S401 to step S412 is repeatedly executed.

  FIG. 9 is a diagram showing a specific example to which the wireless communication system of the present invention is applied. As shown in FIG. 9, as an application example of the wireless communication system in the present embodiment, each HGW 10 used in common in an apartment house or the like is located in each room (room 101, room 102, room 103). The case where the communication terminal 20 to be connected is assumed. As shown in FIG. 9, the communication terminal 20 located in the room 102 communicates with the HGW 10 by simultaneously using a plurality of channels (for example, 52 ch, 56 ch, 124 ch, and 128 ch). In addition, the communication terminal 20 located in the room 103 communicates with the HGW 10 by simultaneously using a plurality of channels (for example, 60 ch, 64 ch, 100 ch, 104 ch, 108 ch, and 112 ch).

  In such a case, according to the conventional technique, the maximum bandwidth that the communication terminal 20 located in the 101st room can use for channel bonding is 80 MHz (for example, 36 ch, 40 ch, 44 ch, and 48 ch which are vacant channels). An empty channel is an available channel. That is, according to the conventional technology, although the empty channels (for example, 116 ch, 120 ch, 132 ch, 136 ch, and 140 ch) that are not adjacent to the above-described empty channels are not used, they cannot be used for channel bonding. There was a problem.

  When the wireless communication system according to the present invention is applied to such a problem, the communication terminal 10 (the communication terminal 10 located in the 101st room) selects a use band according to the number of free channels (available channels). . Next, the communication terminal 10 selects a use channel to be used in the selected use band. And the communication terminal 10 produces | generates a transmission signal by storing the information of the selected utilization channel in a center subcarrier, and transmits to the HGW10 which is a connection destination. In the HGW 10, the usage channel of the own apparatus is selected based on the information of the usage channel stored in the central subcarrier of the transmission signal, and communication is performed between the communication terminal 20 and the HGW 10 using the usage channel. Therefore, an empty channel can be used more efficiently than before, and communication efficiency in wireless communication can be improved.

<Modification>
The second embodiment may be modified in the same manner as the first embodiment.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

10 (10a, 10b) ... HGW (communication device), 20 (20a, 20b) ... communication terminal (communication device), 101 ... communication unit, 102 ... channel scanning unit, 103 ... channel information storage unit, 104 ... determination unit, DESCRIPTION OF SYMBOLS 105 ... Utilization channel selection part, 106 ... Transmission signal generation part, 107 ... Signal processing part, 201 ... Communication part, 202 ... Signal processing part, 203 ... Utilization channel selection part, 204 ... Transmission signal generation part, 205 ... Channel scanning part 206: Channel information storage unit, 207: Determination unit

Claims (4)

A channel selection unit for selecting a combination of a plurality of channels used for communication;
A communication unit that communicates with other communication devices using the selected channel;
A transmission signal generator for generating a transmission signal for transmitting information of the selected channel;
With
The transmission signal generation unit is a communication device that stores information on the selected channel in a subcarrier that is not used for transmission data transmission when generating the transmission signal. The usage channel selection unit includes:
The communication apparatus according to claim 1, wherein a channel to be used is selected from a combination of the plurality of channels in order from a channel having a small influence on the own apparatus. A use channel selection step for selecting a combination of a plurality of channels used for communication;
A communication step of communicating with another communication device using the selected channel;
A transmission signal generation step of generating a transmission signal for transmitting the information of the selected channel;
Have
A communication method for storing information on the selected channel in a subcarrier not used for transmission of transmission data when generating the transmission signal in the transmission signal generation step. A use channel selection step for selecting a combination of a plurality of channels used for communication;
A communication step of communicating with another communication device using the selected channel;
A transmission signal generation step of generating a transmission signal for transmitting the information of the selected channel;
To the computer,
A computer program for storing information on the selected channel in a subcarrier not used for transmission of transmission data when generating the transmission signal in a transmission signal generation step.

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