Wireless communication system

Abstract

In a wireless communication system according to one embodiment of the present invention, a reception device measures a center frequency and a bandwidth of an interference wave with respect to a desired wave and a reception power of the desired wave. The transmission device measures the center frequency and the bandwidth of the interference wave with respect to the desired wave and the reception power of the desired wave, divides, on the basis of the center frequency and the bandwidth of the interference wave measured and the reception power of the desired wave, the frequency band of the desired wave into a component carrier having a part of the frequency band as a non-use band and the remaining frequency band as a use band, and controls, if the DU ratio in the frequency band in the non-use band is a prescribed threshold or lower, so as to perform wireless communication by the divided component carrier.

Description

wireless communication system

[0001] The present invention relates to a wireless communication system in which a transmitting device and a receiving device communicate with each other wirelessly.

[0002] In wireless communication between a transmitting device and a receiving device, if there is interference from other systems or environmental noise within the channel band used by the device itself, it is common for the device to sense available channels and, if an available channel is found, change the channel being used (see, for example, non-patent document 1).

[0003] Furthermore, when a plurality of wireless communication devices transmit radio waves to each other, the other wireless communication devices transmit interference waves to each other.

[0004] Kazuhiro Kosaka and five others, "Study on Frequency Transition Method for Interference Avoidance in FPU for Mobile Transmission," ITE Technical Report, vol. 41, No. 35, BCT2017-88, Oct. 2017

[0005] However, conventionally, if there is no available channel, the channel cannot be changed, and there is a problem that interference waves cannot be avoided.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a wireless communication system that reduces interference between radio waves transmitted by a transmitting device and a receiving device.

[0007] In a wireless communication system according to one embodiment of the present invention, a transmitting device and a receiving device transmit radio waves to each other to perform wireless communication. The receiving device has a receiving side measuring unit that measures the center frequency and bandwidth of an interference wave relative to a received desired wave and the received power of the received desired wave. The transmitting device has a transmitting side measuring unit that measures the center frequency and bandwidth of the interference wave relative to the received desired wave and the received power of the received desired wave, and determines a frequency band to be unused relative to the frequency band of the desired wave based on the center frequency and bandwidth of the interference wave and the received power of the desired wave measured by the receiving side measuring unit and the transmitting side measuring unit, respectively. a determination unit that determines whether a DU ratio in the frequency band that the division unit has designated as an unused band is equal to or less than a predetermined threshold; and a communication control unit that, when the determination unit determines that the DU ratio is greater than the predetermined threshold, expands the frequency range that the division unit designates as an unused band for a desired wave, and, when the determination unit determines that the DU ratio is equal to or less than the predetermined threshold, controls the transmitting device and the receiving device to perform wireless communication using the one or more component carriers that the division unit has divided.

[0008] According to the present invention, it is possible to provide a wireless communication system that reduces interference between radio waves transmitted by a transmitting device and a receiving device.

[0009] 1A is a functional block diagram illustrating functions of a transmitting device and a receiving device included in a wireless communication system according to an embodiment; FIG. 1A is a diagram illustrating a state before a dividing unit performs processing on a channel band used by the transmitting device; FIG. 1B is a diagram schematically illustrating a first example of a state in which the dividing unit divides the frequency band of a desired wave; FIG. 1C is a diagram schematically illustrating a second example of a state in which the dividing unit divides the frequency band of a desired wave; FIG. 1A is a diagram schematically illustrating a first example of a result of a communication control unit controlling the transmitting device to mix Nyquist transmission and FTN transmission; and FIG. 1B is a diagram schematically illustrating a second example of a result of a communication control unit controlling the transmitting device to mix Nyquist transmission and FTN transmission.

[0010] A wireless communication system 1 according to an embodiment will be described below with reference to the drawings. The wireless communication system 1 includes a transmitting device 2 and a receiving device 3, and the transmitting device 2 and the receiving device 3 transmit radio waves to each other to perform wireless communication.

[0011] FIG. 1 is a functional block diagram illustrating the functions of a transmitting device 2 and a receiving device 3 included in a wireless communication system 1 according to an embodiment.

[0012] The receiving device 3 includes, for example, a receiving side measurement unit 30, a channel determination unit 32, a transmission signal conversion unit 34, and a reception signal conversion unit 36.

[0013] The receiver-side measuring unit 30 measures interference waves in the channel band used by its own device and outputs the measurement results to the channel judgment unit 32 and the transmission signal conversion unit 34. For example, the receiver-side measuring unit 30 measures the center frequency of interference waves in the wireless communication (received desired waves) between the transmitter 2 and the receiver 3, the bandwidth of power exceeding a predetermined threshold, and the received power of the desired waves in its own device. In other words, the receiver-side measuring unit 30 has the function of monitoring interference waves in its own device.

[0014] In addition, when monitoring and measuring interference waves, the receiving side measurement unit 30 may use any method such as ``measurement during outage times,'' ``detection using machine learning,'' or ``subtracting its own signal components after demodulation processing and detecting from the remaining components.''

[0015] The channel determination unit 32 determines whether or not there is an interference wave with a power exceeding a predetermined threshold in the channel band used by the device itself, and outputs the determination result to the receiving-side measurement unit 30 and the transmission signal conversion unit 34. If the channel determination unit 32 determines that there is an interference wave with a power exceeding the predetermined threshold, it further determines whether or not the device itself can use another channel, and outputs the determination result to the receiving-side measurement unit 30 and the transmission signal conversion unit 34.

[0016] The transmission signal conversion unit 34 performs processing such as conversion on the signal to be transmitted to the transmitting device 2 so that the signal satisfies predetermined conditions, and transmits the processed signal to the transmitting device 2 .

[0017] For example, if there is an interference wave with power exceeding a predetermined threshold, and the channel determination unit 32 determines that another channel is available, the transmission signal conversion unit 34 changes the channel and notifies the transmitting device 2 of this.

[0018] Furthermore, if the channel determination unit 32 determines that there is an interference wave with power exceeding a predetermined threshold and that other channels are not available, the transmission signal conversion unit 34 converts the center frequency of the interference wave measured by the receiving side measurement unit 30, the bandwidth of the power exceeding the predetermined threshold, and the desired wave reception power of the device itself so as to satisfy predetermined conditions, and notifies the transmitting device 2 of the results.

[0019] The received signal converter 36 receives the signal transmitted by the transmitter 2 so as to satisfy a predetermined condition.

[0020] The transmitting device 2 includes a storage unit 20, a transmitting side measurement unit 21, a channel determination unit 22, a received signal conversion unit 23, a transmitted signal generation unit 24, a communication control unit 26, and a transmitted signal conversion unit 28.

[0021] The storage unit 20 is, for example, a transmission signal candidate database that pre-stores data used by the transmission signal generation unit 24 (tabled data such as candidate combinations of carrier width, MCS, and FTN compression rate, which will be described later).

[0022] The transmitting-side measuring unit 21 measures interference waves in the channel band used by its own device and outputs the measurement results to the channel judgment unit 22. For example, the transmitting-side measuring unit 21 measures the center frequency of interference waves in the wireless communication (received desired waves) between the transmitting device 2 and the receiving device 3, the bandwidth of power exceeding a predetermined threshold, and the received power of the desired waves in its own device. In other words, the transmitting-side measuring unit 21 has the function of monitoring interference waves in its own device.

[0023] In addition, when monitoring and measuring interference waves, the transmitting side measurement unit 21 may use any method such as ``measurement during outage times,'' ``detection using machine learning,'' or ``subtracting its own signal components after demodulation processing and detecting from the remaining components.''

[0024] The channel determination unit 22 determines whether or not there is an interference wave with a power exceeding a predetermined threshold in the channel band used by the device itself, and outputs the determination result to the transmitting side measurement unit 21, the transmission signal generation unit 24, and the transmission signal conversion unit 28. Furthermore, if the channel determination unit 22 determines that there is an interference wave with a power exceeding the predetermined threshold, it further determines whether or not the device itself can use another channel, and outputs the determination result to the transmitting side measurement unit 21, the transmission signal generation unit 24, and the transmission signal conversion unit 28.

[0025] The received signal converter 23 performs processing such as converting the signal received from the receiving device 3 so that it satisfies predetermined conditions, and outputs the processed data to the transmission signal generator 24. For example, the received signal converter 23 outputs to the transmission signal generator 24 a notification that the transmission channel transmitted by the transmission signal converter 34 of the receiving device 3 has been changed, or a notification of the center frequency of the interference wave measured by the receiving-side measuring unit 30, the bandwidth of the power exceeding a predetermined threshold, and the desired wave reception power of the device itself.

[0026] The transmission signal generation unit 24 has, for example, a division unit 240, a waveform generation unit 242, and a judgment unit 244, and performs processing using data input from the channel judgment unit 22, data input from the received signal conversion unit 23, and data stored in the memory unit 20.

[0027] The dividing unit 240 divides the frequency band of the desired wave into one or more component carriers that are used bands, and a part of the frequency band of the desired wave is set as an unused band, based on the center frequency and bandwidth of the interference wave measured by the receiving-side measuring unit 30 and the transmitting-side measuring unit 21, respectively, and the received power of the desired wave. The dividing unit 240 then outputs the division result to the waveform generating unit 242.

[0028] 2A and 2B are diagrams schematically illustrating the functions of the division unit 240. FIG. 2A is a diagram illustrating an example of a state before the division unit 240 performs processing on the channel band (frequency band of the desired wave) used by the transmitting device 2. FIG. 2B is a diagram schematically illustrating a first example of a state in which the division unit 240 has divided the frequency band of the desired wave. FIG. 2C is a diagram schematically illustrating a second example of a state in which the division unit 240 has divided the frequency band of the desired wave. Note that in FIG. 2, the hatched portions indicate interference waves.

[0029] As shown in FIG. 2A, for example, it is assumed that the transmitter 2 performs Nyquist transmission using the frequency band (channel band) of the desired wave.

[0030] In this case, as shown in FIG. 2( b), if an interference wave exists within the channel band used by the transmitting device 2, the dividing unit 240 may divide the frequency band of the interference wave into an unused band and the remaining frequency band into two component carriers that are used bands, so that the transmitting device 2 performs Nyquist transmission.

[0031] 2(c), the dividing unit 240 may divide the frequency band of the interference wave into two component carriers that are used bands, with the frequency band of the interference wave being an unused band, and the transmitting device 2 may perform FTN (Faster-than-Nyquist) transmission. For example, if it is necessary to maintain the transmission rate, the transmitting device 2 may change the MCS (Modulation and Coding Scheme) or adopt FTN transmission.

[0032] At this time, when the transmitting device 2 and the receiving device 3 perform wireless communication using a plurality of subcarriers, the dividing unit 240 sets part of the frequency band of the desired wave as an unused band in units of subcarriers.

[0033] Furthermore, for example, when the transmitting device 2 and the receiving device 3 perform wireless communication using a single carrier, the dividing unit 240 performs carrier division to leave part of the single carrier as an unused band.

[0034] Furthermore, the division unit 240 may change the division method (bandwidth, number, MCS, FTN compression rate, etc.) depending on the bandwidth and frequency of the interference wave.

[0035] The waveform generating unit 242 generates a waveform of the radio wave that will be the transmission signal for each frequency band divided by the dividing unit 240 and outputs it to the determining unit 244 .

[0036] The determination unit 244 determines whether the DU ratio (Desired signal to Undesired signal Ratio) for the waveform output by the waveform generation unit 242 (for example, a waveform within a frequency band that the division unit 240 has designated as an unused band) is below a predetermined threshold, and outputs the determination result to the communication control unit 26 and the division unit 240.

[0037] When the power of the interference wave measured by the receiving device 3 is large, the DU ratio is calculated using the sum of the power of the received waveform spectrum within the interference wave band and the interference wave power measured by the receiving device 3. When the power of the interference wave measured by the transmitting device 2 is large, the DU ratio is calculated using the sum of the power of the transmitted waveform spectrum within the interference wave band and the interference wave power measured by the transmitting device 2.

[0038] In addition, the determination unit 244 may make a determination based on a preset table that uses multiple allowable DU ratios as thresholds corresponding to the division method (bandwidth, MCS, FTN compression rate) used by the division unit 240.

[0039] When the determination unit 244 determines that the DU ratio is greater than a predetermined threshold, the communication control unit 26 controls the transmission signal generation unit 24 to expand the frequency range that the division unit 240 designates as an unused band for the desired wave. Furthermore, when the determination unit 244 determines that the DU ratio is equal to or less than the predetermined threshold, the communication control unit 26 controls the transmission device 2 and the reception device 3 to perform wireless communication using one or more component carriers divided by the division unit 240.

[0040] In addition, the communication control unit 26 may perform Nyquist transmission on a channel with a frequency close to the frequency of the interference wave, and FTN transmission on a channel with a frequency far from the frequency of the interference wave, so that the transmitting device 2 and the receiving device 3 perform wireless communication.

[0041] 3A and 3B are diagrams schematically showing the results of control by the communication control unit 26 so that the transmitter 2 mixes Nyquist transmission and FTN transmission. Fig. 3A is a diagram schematically showing a first example of the results of control by the communication control unit 26 so that the transmitter 2 mixes Nyquist transmission and FTN transmission. Fig. 3B is a diagram schematically showing a second example of the results of control by the communication control unit 26 so that the transmitter 2 mixes Nyquist transmission and FTN transmission. In Fig. 3, the shaded areas indicate interference waves.

[0042] In FTN transmission, because the symbol interval is compressed, the transmission capacity is larger than that of Nyquist transmission with the same bandwidth and MCS, but the interference resistance is reduced. As shown in Figures 3(a) and 3(b), it is sometimes possible to increase the transmission capacity by performing Nyquist transmission on channels with frequencies close to the frequency of the interference wave and FTN transmission on channels with frequencies far from the frequency of the interference wave.

[0043] The transmission signal converter 28 performs wireless communication with the reception signal converter 36 of the receiving device 3 under the control of the communication controller 26 .

[0044] In this way, when an interference wave is present within the channel band to be used, the transmitting device 2 treats the band of the interference wave within the channel band to be used as an unused band, and divides the remaining band within the channel band to be used into one or more component carriers for transmission.

[0045] When transmitting signals using orthogonal frequency-division multiplexing (OFDM) or single-carrier FDMA (SC-FDMA), the transmitting device 2 does not use subcarriers in the interference wave band as carriers in the unused band, and the judgment unit 244 judges whether the DU ratio is equal to or less than a predetermined threshold.

[0046] Furthermore, when transmitting a signal using a single carrier, the transmitting device 2 does not use the band of the interference wave, divides the single carrier into one or more component carriers, and determines whether the DU ratio is equal to or less than a predetermined threshold value using the determining unit 244. At this time, the transmitting device 2 may generate a waveform with an adjusted roll-off rate using the waveform generating unit 242, and determine whether the DU ratio is equal to or less than the predetermined threshold value using the determining unit 244.

[0047] Furthermore, the transmitting device 2 may not only divide the channel band to be used, but also have a function of adjusting the transmission power individually for each component carrier.

[0048] Furthermore, the transmitting device 2 may be configured to divide the channel band to be used and then transmit a mixture of Nyquist transmission and FTN transmission.

[0049] Furthermore, the transmitting device 2 may be configured to provide a margin in the DU ratio or to select component carriers so as to increase the transmission capacity.

[0050] Next, a description will be given of an operation example of the wireless communication system 1. Fig. 4 is a flowchart showing an operation example of the receiving device 3 in the wireless communication system 1 according to one embodiment. As shown in Fig. 4, first, in the process of S100, the receiving device 3 measures (monitors) an interference wave.

[0051] In the processing of S102, the receiving device 3 determines whether or not there is an interference wave exceeding a predetermined threshold, and if there is no interference wave exceeding the threshold (S102: No), it returns to the processing of S100, and if there is an interference wave exceeding the threshold (S102: Yes), it proceeds to the processing of S104.

[0052] In the process of S104, the receiving device 3 determines whether or not other channels are available, and if they are available (S104: Yes), proceeds to the process of S106, and if they are not available (S104: No), proceeds to the process of S108.

[0053] In the process of S106, the receiving device 3 changes the channel and returns to the process of S100, at which time the receiving device 3 notifies the transmitting device 2 that the channel will be changed.

[0054] In the process of S108, the receiving device 3 measures the center frequency of the interference wave, the bandwidth of the interference wave exceeding a predetermined threshold, and the received power of the desired wave of the receiving device 3, and notifies the transmitting device 2 of the measurement results.

[0055] 5 is a flowchart showing an example of the operation of the transmitting device 2 in the wireless communication system 1 according to one embodiment. As shown in FIG. 5, first, in the process of S200, the transmitting device 2 measures (monitors) interference waves.

[0056] In the processing of S202, the transmitting device 2 determines whether or not there is an interference wave exceeding a predetermined threshold, and if there is no interference wave exceeding the threshold (S202: No), it returns to the processing of S200, and if there is an interference wave exceeding the threshold (S202: Yes), it proceeds to the processing of S204.

[0057] In the process of S204, the transmitting device 2 determines whether or not other channels are available, and if they are available (S204: Yes), proceeds to the process of S206, and if they are not available (S204: No), proceeds to the process of S208.

[0058] In the process of S206, the transmitting device 2 changes the channel to perform communication, and then returns to the process of S200.

[0059] In the process of S208, the transmitting device 2 measures the center frequency of the interference wave, the bandwidth of the interference wave exceeding a predetermined threshold, and the received power of the desired wave of the transmitting device 2, and then proceeds to the process of S210.

[0060] In the processing of S210, the transmitting device 2 divides the channel band (carrier) to be used based on the center frequency and bandwidth of the interference wave measured by the transmitting device 2 itself and the center frequency and bandwidth of the interference wave notified by the receiving device 3.

[0061] In the process of S212, the transmitting device 2 generates waveforms for the divided channel bands (carriers).

[0062] In the processing of S214, the transmitting device 2 determines whether the DU ratio of the generated waveform (a waveform within a frequency band that the dividing unit 240 has designated as an unused band) is equal to or less than a predetermined threshold, and if it determines that it is greater than the predetermined threshold (S214: No), it proceeds to processing of S216, and if it determines that it is equal to or less than the predetermined threshold (S214: Yes), it proceeds to processing of S218.

[0063] In the process of S216, the transmitting device 2 expands the unused band for the desired wave and returns to the process of S210.

[0064] In the process of S218, the transmitting device 2 performs wireless communication with the receiving device 3 using one or more component carriers divided by the dividing unit 240.

[0065] In this way, the wireless communication system 1 of one embodiment divides the frequency band of the desired wave based on the center frequency and bandwidth of the interference wave measured by the receiving side measurement unit 30 and the transmitting side measurement unit 21, respectively, so that some of the frequency band is an unused band and the remaining frequency band is one or more component carriers that are used as a used band, and when the DU ratio within the unused frequency band is below a predetermined threshold, wireless communication is performed using one or more of the divided component carriers, thereby reducing interference between the radio waves transmitted by the transmitting device 2 and the receiving device 3.

[0066] In addition, each function possessed by the transmitting device 2 and the receiving device 3 may be configured in part or in whole by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0067] For example, the transmitting device 2 and the receiving device 3 can be realized using a computer and a program, and the program can be recorded on a storage medium or provided via a network.

[0068] 6 is a diagram illustrating an example of a hardware configuration of a transmission device 2 according to an embodiment. As illustrated in FIG. 6, the transmission device 2 has, for example, an input unit 50, an output unit 51, a communication unit 52, a CPU 53, a memory 54, and an HDD 55 connected via a bus 56, and functions as a computer. The transmission device 2 is also configured to input and output data to and from a computer-readable storage medium 57.

[0069] The input unit 50 is, for example, a keyboard and a mouse. The output unit 51 is, for example, a display device such as a display that outputs images. The communication unit 52 is, for example, a wireless network interface, and may have a function as an output unit that outputs data to the outside.

[0070] As described above, the CPU 53 controls each component of the transmitting device 2 and performs predetermined processing, etc. The memory 54 and the HDD 55 are storage units that store data, etc.

[0071] The storage medium 57 is capable of storing programs and the like that cause the transmission device 2 to execute the functions of the transmission device 2. Note that the architecture that configures the transmission device 2 is not limited to the example shown in FIG.

[0072] The functions performed by the components described herein may be implemented in circuitry or processing circuitry, including general purpose processors, application specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), a CPU (a Central Processing Unit), conventional circuits, and / or combinations thereof, programmed to perform the described functions.

[0073] A processor includes transistors and other circuits and is considered to be circuitry or processing circuitry. A processor may be a programmed processor that executes programs stored in memory.

[0074] In this specification, a circuitry, unit, or means is hardware that is programmed to realize or performs the described functions, which may be any hardware disclosed herein or any hardware known to be programmed to realize or perform the described functions.

[0075] If the hardware is a processor considered to be a type of circuitry, the circuitry, means, or unit is a combination of the hardware and software used to configure the hardware and / or processor.

[0076] 1 wireless communication system, 2 transmitting device, 3 receiving device, 20 storage unit, 21 transmitting side measurement unit, 22 channel determination unit, 23 received signal conversion unit, 24 transmitted signal generation unit, 26 communication control unit, 28 transmitted signal conversion unit, 30 receiving side measurement unit, 32 channel determination unit, 34 transmitted signal conversion unit, 36 received signal conversion unit, 50 input unit, 51 output unit, 52 communication unit, 53 CPU, 54 memory, 55 HDD, 56 bus, 57 storage medium, 240 division unit, 242 waveform generation unit, 244 determination unit

Claims

1. A wireless communication system in which a transmitting device and a receiving device transmit radio waves to each other to perform wireless communication, wherein the receiving device has a receiving-side measuring unit that measures the center frequency and bandwidth of an interference wave relative to a received desired wave and the received power of the received desired wave, and the transmitting device has a transmitting-side measuring unit that measures the center frequency and bandwidth of the interference wave relative to a received desired wave and the received power of the received desired wave, a dividing unit that divides the frequency band of the desired wave based on the center frequency and bandwidth of the interference wave and the received power of the desired wave measured by the receiving-side measuring unit and the transmitting-side measuring unit, so that some frequency bands are unused bands and the remaining frequency bands are one or more component carriers that are used bands, and a determining unit that determines whether the DU ratio within the frequency bands that the dividing unit has made unused bands is equal to or less than a predetermined threshold. and a communication control unit that, when the determination unit determines that the DU ratio is greater than a predetermined threshold, causes the division unit to expand a frequency range that is designated as an unused band for a desired wave, and, when the determination unit determines that the DU ratio is equal to or less than the predetermined threshold, controls the transmitting device and the receiving device to perform wireless communication using one or more component carriers divided by the division unit.

2. The wireless communication system according to claim 1, wherein the dividing unit, when the transmitting device and the receiving device perform wireless communication using a plurality of subcarriers, sets a part of the frequency band of the desired wave as an unused band in units of subcarriers.

3. The wireless communication system according to claim 1, wherein when the transmitting device and the receiving device perform wireless communication using a single carrier, the dividing unit sets a part of the single carrier as an unused band.

4. The wireless communication system according to claim 1 or 2, characterized in that the communication control unit performs Nyquist transmission in a channel having a frequency close to the frequency of the interference wave, and performs FTN transmission in a channel having a frequency far from the frequency of the interference wave, thereby controlling wireless communication between the transmitting device and the receiving device.

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