Wireless communication system, transmission device, and wireless communication method

Abstract

An object of the present disclosure is to provide a wireless communication system, a transmission device, and a wireless communication method capable of avoiding an influence of deterioration without shifting a band of a wireless signal even when a frequency domain in which communication quality is deteriorated is included.SOLUTION: A wireless communication system according to the present disclosure includes a transmission device and a reception device. The transmission device is configured to execute a process of detecting a deteriorated frequency region in which communication quality is deteriorated, a process of setting a band left by removing the deteriorated frequency region as a new use band, and a transmission process of transmitting a radio signal after setting a transmission rate of a modulation symbol in the new use band to be higher than that before removal of the deteriorated frequency region. The receiving device is configured to perform a process of receiving a radio signal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a wireless communication system, a transmitting device, and a wireless communication method that avoid degradation of communication quality in wireless communication. [Background technology]

[0002] Patent Document 1 discloses a space diversity technique for receiving wireless signals using two antennas. The diversity effect can avoid degradation of communication quality due to interference waves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-14011 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even if diversity is provided as described above, it may be difficult to avoid interference waves.

[0005] In such cases, one possible solution is to shift the band of the wireless signal to avoid the frequency range where communication quality has deteriorated due to interference. However, this is difficult in reality because a license may be required to use the new band.

[0006] In order to solve the above-mentioned problems, the present disclosure aims to provide a wireless communication system, a transmitting device, and a wireless communication method that can avoid the effects of degradation without shifting the band of a wireless signal even when a frequency range with degraded communication quality is included. [Means for solving the problem]

[0007] A first aspect of the present disclosure is A transmitter and a receiver are provided for wireless communication, The transmitting device A process of detecting a frequency region where communication quality is degraded; A process of removing the frequency region and setting the remaining band as a new usable band; a transmission process of transmitting a radio signal in the new use band at a transmission rate of modulation symbols higher than that before the frequency region is removed; configured to run The receiving device Preferably, the wireless communication system is configured to perform a process for receiving the wireless signal.

[0008] The second aspect is as follows: A process of detecting a frequency region where communication quality is degraded; A process of removing the frequency region and setting the remaining band as a new usable band; a transmission process of transmitting a radio signal in the new use band at a transmission rate of modulation symbols higher than that before the frequency region is removed; Preferably, the transmitting device is configured to perform the following:

[0009] The third aspect is as follows: Detecting a frequency region where communication quality is degraded; A band remaining after removing the frequency region is set as a new usable band; a transmitting device performing a transmission process of transmitting a radio signal in the new use band after increasing the transmission rate of modulation symbols to a rate higher than that before the frequency region is removed; a receiving device receiving the wireless signal; Preferably, the wireless communication method includes: [Effects of the Invention]

[0010] According to an aspect of the present disclosure, a transmitting device removes a frequency range where communication quality is degraded, and uses the remaining band as a new usable band. This allows the influence of degradation to be avoided without shifting the band of the radio signal, even when a frequency range where communication quality is degraded is included. Furthermore, the transmitting device increases the transmission rate of modulation symbols in the new usable band compared to before the removal of the degraded frequency range. This makes it possible to maintain transmission capacity even after band division. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a configuration example of a wireless communication system according to a first embodiment. [Figure 2] 3 is a diagram illustrating a band of a radio signal according to the first embodiment. FIG. [Figure 3] 10A and 10B are diagrams illustrating the effects of the present disclosure. [Figure 4] 1 is a diagram illustrating a hardware configuration of a transmitting device and a receiving device according to a first embodiment. [Figure 5] 4 is a flowchart illustrating processing executed by CPUs of a transmitting device and a receiving device according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Embodiments of the present disclosure will be described with reference to the drawings. The same or corresponding components will be designated by the same reference numerals, and repeated description may be omitted.

[0013] Embodiment 1 1 shows an example of the configuration of a wireless communication system 100 according to the first embodiment. The wireless communication system 100 includes a transmitting device 110 and a receiving device 120. The transmitting device 110 and the receiving device 120 perform wireless communication using single-carrier transmission, in which data to be transmitted is transmitted using one carrier.

[0014] First, the function of the transmitting device 110 will be described. The communication quality measuring device 111 measures communication quality, such as the strength of a wireless signal, as a function of frequency. The communication quality measuring device 111 is, for example, a spectrum analyzer. The communication quality measuring device 111 may also be installed in the receiving device 120. That is, the receiving device 120 may measure the communication quality of the wireless signal, and the measurement result may be fed back to the transmitting device 110.

[0015] The C / N measuring device 112 measures the C / N (Carrier-to-noise ratio) of the radio signal.

[0016] Based on the measurement results of the communication quality, the control circuit 113 detects a degraded frequency region 50 (not shown), which is a frequency region where the communication quality is degraded. The causes of the degradation of the communication quality include multipath interference and interference waves from other electronic devices.

[0017] The control circuit 113 removes the degraded frequency region 50 from the current band and sets the remaining band as the new band to be used. For example, if one band remains as a result of removing the degraded frequency region 50, the one band is set as the new band to be used. On the other hand, if the band is divided into multiple bands as a result of removing the degraded frequency region 50, the multiple divided bands are set as the new bands to be used.

[0018] Furthermore, the control circuit 113 determines whether the number of modulation levels can be increased to a level higher than that before removing the degraded frequency region 50, based on the C / N of the band to be newly used. Specifically, it determines whether there is a modulation method that can be used with the measured C / N among modulation levels higher than that before removing the degraded frequency region 50. As the modulation method, digital modulation such as QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), and 64QAM can be used.

[0019] If it is determined that the multi-level number can be increased, the control circuit 113 determines the destination of the increased multi-level number and notifies the Nyquist transmission circuit 115 of this together with information about the new bandwidth to be used. Furthermore, the control circuit 113 notifies the switching circuit 114 to send new transmission data to the Nyquist transmission circuit 115.

[0020] On the other hand, if it is not determined that the number of levels can be increased, control circuit 113 notifies switching circuit 114 to send new transmission data to FTN transmission circuit 116. Control circuit 113 also notifies FTN transmission circuit 116 of information on the new bandwidth to be used.

[0021] The switching circuit 114 receives new transmission data from an upper layer or other device via the main signal system, and sends the transmission data to the Nyquist transmission circuit 115 or the FTN transmission circuit 116 according to the decision of the control circuit 113.

[0022] Nyquist transmission circuit 115 includes a first Nyquist transmission circuit 115-1 that is preferentially used as a working system, and a second Nyquist transmission circuit 115-2 that is used auxiliary as a redundant system. If there is one new usable band, first Nyquist transmission circuit 115-1 is used. If there are two new usable bands, first Nyquist transmission circuit 115-1 is responsible for transmission of the first usable band, and second Nyquist transmission circuit 115-2 is responsible for transmission of the second usable band.

[0023] In response to the notification from control circuit 113, first Nyquist transmission circuit 115-1 modulates the transmission data with the increased multi-level number to generate modulation symbols. Furthermore, first Nyquist transmission circuit 115-1 multiplexes the modulation symbols in the new operating band at a rate equal to or lower than the Nyquist rate. Furthermore, first Nyquist transmission circuit 115-1 transmits the multiplexed modulation symbols as a radio signal to receiving device 120. The radio signal includes information about the operating band handled by first Nyquist transmission circuit 115-1 and information about the transmission method.

[0024] The second Nyquist transmission circuit 115-2 performs the same processing as the first Nyquist transmission circuit 115-1, except that it is responsible for transmission for the second usable band.

[0025] If there are two new usable bands, the transmission data may be bit-decomposed to match the bandwidths of the two usable bands and then distributed to first Nyquist transmission circuit 115-1 and second Nyquist transmission circuit 115-2. Alternatively, the transmission data may be sent to first Nyquist transmission circuit 115-1 and second Nyquist transmission circuit 115-2 without being bit-decomposed. The same applies to first FTN transmission circuit 116-1 and second FTN transmission circuit 116-2.

[0026] FTN transmission circuit 116 includes first FTN transmission circuit 116-1, which is preferentially used as a working system, and second FTN transmission circuit 116-2, which is used auxiliary as a redundant system. When there is one new band in use, first FTN transmission circuit 116-1 is used. When there are two new bands in use, first FTN transmission circuit 116-1 is responsible for transmission of the first band in use, and second FTN transmission circuit 116-2 is responsible for transmission of the second band in use.

[0027] The first FTN transmission circuit 116-1 generates modulation symbols by modulating the transmission data with a predetermined modulation level. The predetermined modulation level may be the same as the modulation level before the degraded frequency region 50 is removed, or a lower level. The first FTN transmission circuit 116-1 multiplexes the modulation symbols in the new operating band at a rate faster than the Nyquist rate. That is, it multiplexes the symbols using FTN (Faster Than Nyquist). The compression rate of the modulation symbols is determined appropriately depending on factors such as communication quality. The first FTN transmission circuit 116-1 transmits the multiplexed modulation symbols as a radio signal to the receiving device 120. The radio signal includes information about the operating band handled by the first FTN transmission circuit 116-1 and information about the transmission method.

[0028] Second FTN transmission circuit 116-2 performs the same processing as first FTN transmission circuit 116-1, except that it is responsible for transmission for the second available band.

[0029] Next, the functions of the receiving device 120 will be described. The Nyquist receiving circuit 121 includes a first Nyquist receiving circuit 121-1 and a second Nyquist receiving circuit 121-2. The first Nyquist receiving circuit 121-1 performs signal processing on the radio signal transmitted from the first Nyquist transmission circuit 115-1 and receives data. Similarly, the second Nyquist receiving circuit 121-2 performs signal processing on the radio signal transmitted from the second Nyquist transmission circuit 115-2 and receives data.

[0030] FTN receiver circuit 122 includes first FTN receiver circuit 122-1 and second FTN receiver circuit 122-2. First FTN receiver circuit 122-1 performs signal processing on the wireless signal transmitted from first FTN transmission circuit 116-1 and receives data. Similarly, second FTN receiver circuit 122-2 performs signal processing on the wireless signal transmitted from second FTN transmission circuit 116-2 and receives data.

[0031] The data received by the Nyquist receiving circuit 121 and the FTN receiving circuit 122 is sent to an upper layer or other device via a common main signal path.

[0032] Hereinafter, the transmission of radio signals performed by first Nyquist transmission circuit 115-1 and second Nyquist transmission circuit 115-2 will be referred to as Nyquist transmission. That is, the process of multiplexing modulation symbols at a rate equal to or lower than the Nyquist rate and the process of transmitting the multiplexed modulation symbols to receiving device 120 as a radio signal will be referred to as Nyquist transmission.

[0033] Similarly, the transmission of radio signals performed by first FTN transmission circuit 116-1 and second FTN transmission circuit 116-2 is referred to as FTN transmission. That is, the process of multiplexing modulation symbols at a rate faster than the Nyquist rate and the process of transmitting the multiplexed modulation symbols as a radio signal to receiving device 120 are referred to as FTN transmission.

[0034] 2 is a diagram showing the band of a radio signal according to the first embodiment. The horizontal axis represents frequency. When no degraded frequency region 50 is included (top diagram), the transmitting device 110 performs Nyquist transmission.

[0035] When a degraded frequency region 50 exists in the center of the band (middle diagram), the transmitting device 110 removes the degraded frequency region 50 by dividing the band into a lower frequency side and a higher frequency side than the degraded frequency region 50. Note that when there are multiple degraded frequency regions 50 within a band, the band may be divided into three or more.

[0036] By removing the degraded frequency region 50, both of the remaining two bands become new usable bands (bottom diagram). In the new usable band, a guard band 10 is provided in the portion adjacent to the degraded frequency region 50. This makes it possible to avoid interference with the degraded frequency region 50.

[0037] It should be noted that if the degraded frequency region 50 exists at the edge of the band, removing the degraded frequency region 50 leaves only one band, and the number of usable bands is also one.

[0038] FIG. 3 is a diagram illustrating the effects of the present disclosure. The horizontal axis represents time. Initially, during normal times when communication quality is not degraded, the transmitting device 110 performs Nyquist transmission, thereby maintaining a high transmission capacity. However, as communication quality deteriorates, the transmission capacity decreases. In such a case, the transmitting device 110 of the present disclosure removes the degraded frequency region 50 from the current band and sets the remaining band as the new band to be used. This makes it possible to avoid the effects of degradation without shifting the band.

[0039] In the present disclosure, although the bandwidth inevitably narrows when the degraded frequency region 50 is removed, an effort is made to maintain the transmission capacity by increasing the transmission rate of the modulation symbols. Specifically, when the C / N ratio is good, the transmission rate of the modulation symbols is increased by increasing the number of modulation levels compared to before the removal of the degraded frequency region 50. On the other hand, when the C / N ratio is not good and the number of modulation levels cannot be increased, the transmission rate is increased by switching to FTN transmission, although this means accepting inter-symbol interference.

[0040] Furthermore, in the present disclosure, when a band is divided into multiple bands by removing the degraded frequency region 50, the multiple divided bands are set as new usable bands, thereby enabling effective use of the band remaining after removing the degraded frequency region 50.

[0041] 4 is a diagram showing the hardware configuration of the transmitting device 110 and the receiving device 120 according to the first embodiment. The processing performed by the transmitting device 110 and the receiving device 120 may be executed by a program using a computer having a CPU and memory and storing a wireless communication program in the memory. Alternatively, the processing may be executed by a program using an integrated circuit such as an FPGA (Field Programmable Gate Array). The wireless communication program may be provided by being recorded on a storage medium, or may be provided via a network.

[0042] The transmitting device 110 and the receiving device 120 have computer functions, with an input unit 40, an output unit 41, a communication unit 42, a CPU (Central Processing Unit, also called a processor) 43, a memory 44, and an HDD (Hard Disk Drive) 45 connected via a bus 46. The transmitting device 110 and the receiving device 120 are also configured to be able to input and output data to and from a computer-readable storage medium 47.

[0043] The input unit 40 is, for example, a keyboard and a mouse, etc. The output unit 41 is, for example, a display device such as a display.

[0044] The communication unit 42 is, for example, a communication interface for the transmitting device 110 and the receiving device 120 to communicate with each other.

[0045] The memory 44 may be, for example, a volatile or non-volatile semiconductor memory such as a RAM, a ROM, or a flash memory, or a magnetic disk, a flexible disk, an optical disk, a DVD, or the like.

[0046] The CPU 43 controls each unit constituting the transmitting device 110 and the receiving device 120, and performs predetermined processing, etc. The memory 44 and the HDD 45 are storage devices that store, for example, a wireless communication program.

[0047] The storage medium 47 is capable of storing a wireless communication program or the like that causes the transmitting device 110 and the receiving device 120 to execute the functions of the transmitting device 110 and the receiving device 120. The storage medium 47 is a USB (Universal Serial Bus) memory, a CD-ROM (Compact Disc Read Only Memory), or the like.

[0048] The architecture configuring the transmitting device 110 and the receiving device 120 is not limited to the example shown in the figure.

[0049] 5 is a flowchart illustrating processing executed by CPU 43 of transmitting device 110 and receiving device 120 according to the first embodiment. CPU 43 reads a wireless communication program stored in memory 44 or HDD 45 and executes the following processing.

[0050] First, the transmitting device 110 measures the communication quality of the wireless signal as a function of frequency (step S01). Next, the transmitting device 110 determines whether or not a degraded frequency region 50 has been detected (step S02). Note that machine learning may be used for the determination.

[0051] If the degraded frequency region 50 is not detected, the process returns to step S01 and continues monitoring the communication quality. On the other hand, if it is determined that the degraded frequency region 50 is detected, the transmitting device 110 removes the degraded frequency region 50 from the current band and sets the remaining band as the new band to be used (step S03).

[0052] Furthermore, the transmitting device 110 transmits the radio signal in the new band in use after increasing the transmission rate of the modulation symbols to be higher than that before removing the degraded frequency region 50. Specifically, the following steps S04 and onward are executed.

[0053] Based on the C / N of the new band in use, the transmitting device 110 determines whether the number of signal levels can be increased from that before the degraded frequency region 50 was removed (step S04).

[0054] If it is determined that the number of modulation levels can be increased, the transmitting device 110 increases the number of modulation levels of the modulation symbols from that before the removal of the degraded frequency region 50, and then performs Nyquist transmission of the transmission data in the new used band (step S05). After transmitting the wireless signal, the process returns to step S01 again.

[0055] Thereafter, receiving device 120 receives the radio signal from transmitting device 110 (step S06).

[0056] On the other hand, if it is not determined in step S04 that the number of levels can be increased, the transmitting device 110 performs FTN transmission of the transmission data in the new band to be used (step S07).After transmitting the wireless signal, the process returns to step S01 again.

[0057] Thereafter, receiving device 120 receives the radio signal from transmitting device 110 (step S08).

[0058] As explained above, the transmitting device 110 of the present disclosure removes the degraded frequency region 50 from the current band, and sets the remaining band as the new band to be used. This makes it possible to avoid the effects of degradation without shifting the band. Furthermore, the transmitting device 110 increases the transmission rate of modulation symbols in the new band to be used compared to before the degraded frequency region 50 was removed. This makes it possible to maintain transmission capacity even after band division.

[0059] <Variation 1> It should be noted that the present disclosure is not limited to radio signals for single-carrier transmission, but may be applied to one or more bands in radio signals for multi-carrier transmission including multiple bands.

[0060] <Variation 2> In the above description, it has been explained that when the number of modulation levels can be increased, the transmitting device 110 increases the number of modulation levels of the modulation symbols and then performs Nyquist transmission of the transmission data. However, when the number of modulation levels can be increased, the transmission method is not limited to Nyquist transmission, and FTN transmission may also be used. This allows the effects of increasing the number of modulation levels and FTN transmission to be obtained simultaneously, making it possible to further increase the transmission speed.

[0061] <Variation 3> In the above description, when the modulation level cannot be increased, the transmitting device 110 performs FTN transmission of the transmission data in a new used band. However, the transmission method when the modulation level cannot be increased does not have to be limited to FTN transmission. In other words, even if the rate is lower than the Nyquist rate, it is possible to increase the transmission speed by multiplexing the modulation symbols at a rate faster than before removing the frequency domain, and the above-mentioned effects can be obtained.

[0062] The present disclosure is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the present disclosure. Furthermore, the embodiments and modifications may be implemented in appropriate combinations, in which case the combined effects can be obtained. [Explanation of symbols]

[0063] 10 Guard band, 40 Input unit, 41 Output unit, 42 Communication unit, 43 CPU, 44 Memory, 46 Bus, 47 Storage medium, 50 Degraded frequency region, 100 Wireless communication system, 110 Transmitting device, 111 Communication quality measuring device, 112 C / N measuring device, 113 Control circuit, 114 Switching circuit, 115-1 First Nyquist transmission circuit, 115-2 Second Nyquist transmission circuit, 116-1 First FTN transmission circuit, 116-2 Second FTN transmission circuit, 120 Receiving device, 121-1 First Nyquist receiving circuit, 121-2 Second Nyquist receiving circuit, 122-1 First FTN receiving circuit, 122-2 Second FTN receiving circuit

Claims

1. A transmitter and a receiver are provided for wireless communication, The transmitting device A process of detecting a frequency region where communication quality is degraded; A process of removing the frequency region and setting the remaining band as a new usable band; a transmission process of transmitting a radio signal in the new use band at a transmission rate of modulation symbols higher than that before the frequency region is removed; configured to run The receiving device A wireless communication system configured to perform a process for receiving the wireless signal.

2. The transmission process includes: The method further includes a process of determining whether or not the number of levels of the modulation symbol can be increased compared to before the removal of the frequency domain, based on the C / N of the new used band; If the number of modulation levels can be increased, the transmission rate is increased by multiplexing the modulation symbols modulated with a higher number of modulation levels than before the removal of the frequency domain; 2. The wireless communication system according to claim 1, wherein, when the number of multi-levels cannot be increased, the transmission rate is increased by multiplexing the modulation symbols at a rate higher than that before the removal of the frequency domain.

3. When a plurality of bands remain after removing the frequency region, the new usable band includes the plurality of bands, The wireless communication system according to claim 1 , wherein the transmission process is performed for each of the new available bands.

4. The wireless communication system according to claim 1 , wherein a guard band is provided in a portion of the new usable band adjacent to the frequency region.

5. A process of detecting a frequency region where communication quality is degraded; A process of removing the frequency region and setting the remaining band as a new usable band; a transmission process of transmitting a radio signal in the new use band at a transmission rate of modulation symbols higher than that before the frequency region is removed; a transmitting device configured to perform the

6. The transmission process includes: The method further includes a process of determining whether or not the number of levels of the modulation symbol can be increased compared to before the removal of the frequency domain, based on the C / N of the new used band; If the number of modulation levels can be increased, the transmission rate is increased by multiplexing the modulation symbols modulated with a higher number of modulation levels than before the removal of the frequency domain; 6. The transmitting device according to claim 5, wherein when the number of multi-levels cannot be increased, the transmission rate is increased by multiplexing the modulation symbols at a rate higher than that before the removal of the frequency domain.

7. Detecting a frequency region where communication quality is degraded; A band remaining after removing the frequency region is set as a new usable band; a transmitting device performing a transmission process of transmitting a radio signal in the new use band after increasing the transmission rate of modulation symbols to a rate higher than that before the frequency region is removed; a receiving device receiving the wireless signal; A wireless communication method comprising:

8. The transmission process includes: The method further includes determining whether or not the number of modulation levels of the modulation symbols can be increased compared to before the removal of the frequency domain, based on the C / N of the new used band; If the number of modulation levels can be increased, the transmission rate is increased by multiplexing the modulation symbols modulated with a higher number of modulation levels than before the removal of the frequency domain; 8. The wireless communication method according to claim 7, wherein, when the number of multi-levels cannot be increased, the transmission rate is increased by multiplexing the modulation symbols at a rate higher than that before the removal of the frequency domain.

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