Wireless communication system and transmission device

Abstract

The purpose of the present disclosure is to provide a wireless communication system and a transmission device that, even when the band of a wireless signal includes a frequency region for which communication quality is degraded, make it possible to avoid the effects of degradation without shifting the band. The wireless communication system comprises a transmission device and a reception device that wirelessly communicate. The transmission device is configured to perform: a process for detecting a frequency region for which communication quality is degraded; a process for dividing the band of a wireless signal to avoid said frequency region; a process for setting the divided band having the greatest bandwidth as a new band to be used; and a transmission process for setting the transmission speed of a modulation symbol in the new band to be used to be higher than before band division and then transmitting the wireless signal. The reception device is configured to perform a process for receiving the wireless signal transmitted from the transmission device.

Description

Wireless communication system and transmitting device

[0001] The present disclosure relates to a wireless communication system and a transmission device that avoid degradation of communication quality in wireless communication.

[0002] Patent Document 1 discloses a space diversity technique for receiving wireless signals using two antennas, which makes it possible to avoid degradation of communication quality due to interference waves by utilizing the diversity effect.

[0003] Japanese Patent Application Publication No. 6-14011

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

[0005] In such cases, one possible method is to shift the band of the wireless signal to avoid the frequency range where communication quality has deteriorated due to interference. However, in reality, this is difficult 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 and a transmitting device that can avoid the effects of degradation without shifting the band of the wireless signal even when a frequency range with degraded communication quality is included.

[0007] A first aspect of the present disclosure is preferably a wireless communication system comprising a transmitting device and a receiving device for wireless communication, wherein the transmitting device is configured to perform the following processes: a process of detecting a frequency region where communication quality is degraded; a process of dividing the band of a wireless signal so as to avoid the frequency region; a process of designating the divided band having the widest bandwidth as a new band to be used; and a transmission process of transmitting a wireless signal in the new band to be used after increasing the transmission rate of modulation symbols in the new band to be used compared to before the band was divided; and the receiving device is configured to perform the process of receiving the wireless signal transmitted from the transmitting device.

[0008] In addition, the second aspect is preferably a transmitting device configured to perform the following processes: detecting a frequency region where communication quality is degraded; dividing the band of a radio signal so as to avoid the frequency region; designating the divided band having the widest bandwidth as a new band to be used; and transmitting the radio signal in the new band to be used after increasing the transmission rate of modulation symbols in the new band to be used compared to before the band was divided.

[0009] According to an aspect of the present disclosure, a transmitting device divides a radio signal into bands so as to avoid frequency regions where communication quality is degraded, and designates the widest divided band as the new operating band. This allows the effects of degradation to be avoided without shifting the band. Furthermore, the transmitting device increases the transmission rate of modulation symbols in the new operating band compared to before the band division. This strives to maintain transmission capacity even after the band division.

[0010] 1 is a configuration example of a wireless communication system according to embodiment 1. FIG. 2 is a diagram illustrating a band of a wireless signal according to embodiment 1. FIG. 3 is a diagram illustrating an effect of the present disclosure. FIG. 4 is a diagram illustrating a hardware configuration of a transmitting device and a receiving device according to embodiment 1. FIG. 5 is a flowchart illustrating processing executed by a CPU of the transmitting device and the receiving device according to embodiment 1.

[0011] 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.

[0012] 1 shows an example of the configuration of a wireless communication system 100 according to embodiment 1. 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 a single carrier.

[0013] 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. In other words, the receiving device 120 may measure the communication quality of the wireless signal, and the measurement results may be fed back to the transmitting device 110.

[0014] The C / N measuring device 112 measures the C / N (Carrier-to-noise ratio) of the radio signal.

[0015] Based on the measurement results of the communication quality, the control circuit 113 detects a frequency region 50 (not shown) 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.

[0016] The control circuit 113 determines a method for dividing the current band so as to avoid the frequency region 50 where communication quality is degraded. Furthermore, when the band is divided according to the determined division method, the control circuit 113 sets the divided band having the widest bandwidth as the new band to be used.

[0017] Furthermore, the control circuit 113 determines whether the number of modulation levels can be increased from that before the band division based on the C / N of the newly used band. Specifically, it determines whether there is a modulation method with a higher order than the number of modulation levels before the band division that can be used with the measured C / N. As the modulation method, for example, digital modulation such as QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), and 64QAM can be used.

[0018] 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 116 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 116.

[0019] On the other hand, if it is not determined that the number of levels can be increased, the control circuit 113 notifies the switching circuit 114 to send new transmission data to the FTN transmission circuit 115. The control circuit 113 also notifies the FTN transmission circuit 115 of information on the new band to be used.

[0020] The switching circuit 114 receives new transmission data from an upper layer or another device via the main signal system, and sends the transmission data to the FTN transmission circuit 115 or the Nyquist transmission circuit 116 according to the decision of the control circuit 113.

[0021] Nyquist transmission circuit 116 modulates the transmission data with the increased multi-level number in accordance with the notification from control circuit 113 to generate modulation symbols. Furthermore, Nyquist transmission circuit 116 multiplexes the modulation symbols in the new band used at a rate equal to or lower than the Nyquist rate. Furthermore, Nyquist transmission circuit 116 transmits the multiplexed modulation symbols as a radio signal to receiving device 120.

[0022] Meanwhile, the FTN transmission circuit 115 generates modulation symbols by modulating the transmission data with a predetermined multi-level number. The predetermined multi-level number may be, for example, the same multi-level number as before the band was divided, or a lower multi-level number. Furthermore, the FTN transmission circuit 115 multiplexes the modulation symbols in the new band used at a rate faster than the Nyquist rate. That is, it multiplexes the symbols using FTN (Faster Than Nyquist). Here, multiplexing processing is performed based on parameters determined by the parameter determination circuit 117. The FTN transmission circuit 115 transmits the multiplexed modulation symbols to the receiving device 120 as a radio signal.

[0023] The parameter determination circuit 117 determines parameters necessary for FTN signal processing, such as the compression rate of modulation symbols. The parameter determination circuit 117 is equipped with a learning model for determining parameters. The learning model learns parameters to be optimal depending on communication quality, etc.

[0024] Next, the functions of the receiving device 120 will be described. The Nyquist receiving circuit 122 performs signal processing on the radio signal transmitted from the Nyquist transmission circuit 116 and receives data. The FTN receiving circuit 121 performs signal processing on the radio signal transmitted from the FTN transmission circuit 115 and receives data. The data received by the Nyquist receiving circuit 122 and the FTN receiving circuit 121 is sent to a higher layer or another device via a common main signal system.

[0025] Hereinafter, the transmission of radio signals performed by the Nyquist transmission circuit 116 of the transmitting device 110 will be referred to as Nyquist transmission. That is, the process performed by the Nyquist transmission circuit 116 of multiplexing modulation symbols at a rate equal to or lower than the Nyquist rate and the process of transmitting the multiplexed modulation symbols as radio signals to the receiving device 120 will be referred to as Nyquist transmission.

[0026] Similarly, the radio signal transmission method performed by the FTN transmission circuit 115 is referred to as FTN transmission. That is, the process performed by the FTN transmission circuit 115 of multiplexing modulation symbols at a rate faster than the Nyquist rate and transmitting the multiplexed modulation symbols as a radio signal to the receiving device 120 is referred to as FTN transmission.

[0027] 2 is a diagram showing the band of a radio signal according to the first embodiment. The horizontal axis represents frequency. When a frequency region 50 in which communication quality is degraded is not included (top diagram), the transmitting device 110 performs Nyquist transmission.

[0028] When a frequency region 50 in which communication quality is degraded is included (middle diagram), the transmitting device 110 divides the band into a lower frequency side and a higher frequency side than the frequency region 50. Note that when there are multiple frequency regions 50 within the band of the wireless signal, the band may be divided into multiple parts.

[0029] In order to effectively utilize the bandwidth, the divided band having the widest bandwidth is set as the new band to be used (see the bottom diagram). In the new band to be used, a guard band 10 is provided in the part adjacent to the frequency region 50 where communication quality is degraded.

[0030] 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 divides the band of the wireless signal so as to avoid the frequency region 50 where communication quality is degraded, and sets the widest divided band as the new band to be used. This makes it possible to avoid the effects of degradation without shifting the band.

[0031] In the present disclosure, although band division inevitably narrows the bandwidth compared to before division, an effort is made to maintain transmission capacity by increasing the transmission rate of modulation symbols. Specifically, when the C / N ratio is good, the number of modulation levels is increased compared to before band division, thereby increasing the transmission rate of modulation symbols. 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.

[0032] 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 provided via a network.

[0033] 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 capable of inputting and outputting data to and from a computer-readable storage medium 47.

[0034] 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.

[0035] The communication unit 42 is a communication interface that enables the transmitting device 110 and the receiving device 120 to communicate with each other, for example.

[0036] 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.

[0037] The CPU 43 controls each component of 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, wireless communication programs.

[0038] The storage medium 47 is capable of storing a wireless communication program or the like that executes 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.

[0039] The architecture configuring the transmitting device 110 and the receiving device 120 is not limited to the example shown in the figure.

[0040] 5 is a flowchart illustrating processing executed by the CPU 43 of the transmitting device 110 and the receiving device 120 according to the first embodiment. The CPU 43 reads a wireless communication program stored in the memory 44 or the HDD 45 and executes the following processing.

[0041] 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 a frequency region 50 in which communication quality is degraded has been detected (step S02). Note that machine learning may be used for this determination.

[0042] If a frequency region 50 in which communication quality is degraded is not detected, the process returns to step S01 and continues monitoring communication quality. On the other hand, if a frequency region 50 in which communication quality is degraded is detected, the transmitting device 110 determines a method for dividing the band so as to avoid the frequency region 50. The transmitting device 110 determines the divided band having the widest bandwidth when the band is divided according to the determined division method as the new band to be used (step S03).

[0043] Furthermore, the transmitting device 110 transmits the radio signal in the new usable band at a higher transmission rate of the modulation symbols than before the band was divided. Specifically, the following steps S04 and onward are executed.

[0044] The transmitting device 110 determines whether the number of multilevels can be increased from that before the band division based on the C / N of the new band to be used (step S04).

[0045] If it is determined that the number of levels can be increased, the transmitting device 110 increases the number of levels of the modulation symbols from that before the band was divided, and then performs Nyquist transmission of the transmission data in the new band used (step S05). After transmitting the radio signal, the process returns to step S01.

[0046] Thereafter, receiving device 120 receives the radio signal from transmitting device 110 (step S06).

[0047] On the other hand, if it is determined in step S04 that the number of levels can not 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 radio signal, the process returns to step S01 again.

[0048] Thereafter, receiving device 120 receives the radio signal from transmitting device 110 (step S08).

[0049] As described above, the transmitting device 110 of the present disclosure divides the radio signal into bands so as to avoid the frequency region 50 where communication quality is degraded, and sets the widest divided band as the new operating band. This makes it possible to avoid the effects of degradation without shifting the band. Furthermore, the transmitting device increases the transmission rate of modulation symbols in the new operating band compared to before the band division. This makes it possible to maintain transmission capacity even after the band division.

[0050] <Modification 1> The present disclosure is not limited to single-carrier transmission radio signals. In a multi-carrier transmission radio signal including multiple bands, the present disclosure may be applied to one or more bands.

[0051] <Variation 2> In the above description, 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.

[0052] <Variation 3> In the above description, when the number of modulation levels cannot be increased, the transmitting device 110 performs FTN transmission of the transmission data in the new used band. However, the transmission method when the number of modulation levels 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 higher than before the band was divided, thereby achieving the above-mentioned effects.

[0053] 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.

[0054] 10 Guard band, 40 Input unit, 41 Output unit, 42 Communication unit, 43 CPU, 44 Memory, 46 Bus, 47 Storage medium, 50 Frequency domain, 100 Wireless communication system, 110 Transmitting device, 111 Communication quality measuring device, 112 C / N measuring device, 113 Control circuit, 114 Switching circuit, 115 FTN transmission circuit, 116 Nyquist transmission circuit, 117 Parameter determination circuit, 120 Receiving device, 121 FTN receiving circuit, 122 Nyquist receiving circuit

Claims

1. A wireless communication system comprising a transmitting device and a receiving device for wireless communication, wherein the transmitting device is configured to perform the following processes: a process of detecting a frequency region where communication quality is degraded; a process of dividing the band of a wireless signal so as to avoid the frequency region; a process of designating the divided band having the widest bandwidth as a new band to be used; and a transmission process of transmitting a wireless signal in the new band to be used after increasing the transmission rate of modulation symbols in the new band to be used compared to before the band was divided; and the receiving device is configured to perform the process of receiving the wireless signal transmitted from the transmitting device.

2. The wireless communication system of claim 1, wherein the transmission process further includes a process of determining whether the number of levels of the modulation symbols can be increased compared to before the band was divided, based on the C / N of the new band used; if the number of levels can be increased, the transmission speed is increased by multiplexing the modulation symbols modulated at a higher number of levels than before the band was divided; and if the number of levels cannot be increased, the transmission speed is increased by multiplexing the modulation symbols at a rate faster than before the band was divided.

3. A transmitting device configured to perform the following processes: detecting a frequency region where communication quality is degraded; dividing the band of a radio signal so as to avoid said frequency region; designating the divided band having the widest bandwidth as a new band to be used; and transmitting a radio signal in said new band to be used after increasing the transmission rate of modulation symbols in said new band to be used compared to before said band was divided.

4. The transmitting device of claim 3, wherein the transmission process further includes a process of determining whether the number of levels of the modulation symbols can be increased compared to before the band was divided, based on the C / N of the new band used; if the number of levels can be increased, the transmission speed is increased by multiplexing the modulation symbols modulated at a higher number of levels than before the band was divided; and if the number of levels cannot be increased, the transmission speed is increased by multiplexing the modulation symbols at a faster rate than before the band was divided.

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