Radio communications system, transmitter, radio communication method, and radio communication program

Abstract

To provide a radio communications system capable of expanding a band of a channel.SOLUTION: A radio communications system of the present disclosure comprises a transmitter and a received that perform a radio communication by using a plurality of channels. The transmitter determines whether or not a requirement band is secured as a whole of the plurality of channels. In the case where it is not recognized that the requirement band is secured, it is determined that a Nyquist multiplex processing for multiplying a symbol at a rate that is a Nyquist rate or lower than in each of the plurality of channels is executed, or FTN multiplex processing for multiplying the symbol at a rate that is higher than that of the Nyquist rate is executed. A switch for executing the FTN multiplex processing is made to the channel to which the Nyquist multiplex processing is executed. Or, a compression ratio of the channel to which the FTN multiplex processing is executed is changed to a compression ratio for securing a requirement band.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a wireless communication system, a transmitter, a wireless communication method, and a wireless communication program that use FTN (Faster Than Nyquist) transmission. [Background technology]

[0002] Patent Document 1 discloses a technique for time-division multiplexing signals in a first radio resource region that multiplexes symbols at a rate equal to or lower than the Nyquist rate and a second radio resource region that multiplexes symbols at a rate higher than the Nyquist rate. This makes it possible to realize large-capacity transmission by FTN while reducing the effect of interference in the first radio resource region. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-164257 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned method, the compression rate is fixed, so the channel bandwidth cannot be expanded.

[0005] In order to solve the above-mentioned problems, a first object of the present disclosure is to provide a wireless communication system capable of expanding a channel bandwidth.

[0006] A second object of the present disclosure is to provide a transmitter capable of expanding a channel bandwidth.

[0007] A third object of the present disclosure is to provide a wireless communication method capable of expanding a channel bandwidth.

[0008] A fourth object of the present disclosure is to provide a wireless communication program capable of expanding a channel bandwidth. [Means for solving the problem]

[0009] The first aspect of the present disclosure is A transmitter and a receiver for wireless communication using a plurality of channels, The transmitter includes: A process of determining whether a necessary bandwidth is secured for the plurality of channels as a whole; a process of determining whether a Nyquist multiplexing process for multiplexing symbols at a rate equal to or lower than the Nyquist rate or an FTN multiplexing process for multiplexing symbols at a rate higher than the Nyquist rate is performed for each of the plurality of channels when it is determined that the necessary bandwidth is not secured; a selection process for selecting and executing at least one of a switching process for switching the channel on which the Nyquist multiplexing process has been performed to perform the FTN multiplexing process, and a change process for changing the compression ratio of the channel on which the FTN multiplexing process has been performed to a compression ratio that can secure the required bandwidth and then performing the FTN multiplexing process again; transmitting traffic to the receiver via the channel on which the switching or changing process has been performed; Preferably, the wireless communication system is configured to:

[0010] The second aspect is as follows: A transmitter that wirelessly communicates with a receiver using a plurality of channels, A process of determining whether a necessary bandwidth is secured for the plurality of channels as a whole; a process of determining whether a Nyquist multiplexing process for multiplexing symbols at a rate equal to or lower than the Nyquist rate or an FTN multiplexing process for multiplexing symbols at a rate higher than the Nyquist rate is performed for each of the plurality of channels when it is determined that the necessary bandwidth is not secured; a selection process for selecting and executing at least one of a switching process for switching the channel on which the Nyquist multiplexing process has been performed to perform the FTN multiplexing process, and a change process for changing the compression ratio of the channel on which the FTN multiplexing process has been performed to a compression ratio that can secure the required bandwidth and then performing the FTN multiplexing process again; transmitting traffic to the receiver via the channel on which the switching or changing process has been performed; Preferably, the method is configured to execute:

[0011] The third aspect is as follows: A transmitter that wirelessly communicates with a receiver using a plurality of channels, determining whether a necessary bandwidth is secured for the plurality of channels as a whole; When it is not recognized that the necessary bandwidth is secured, determining whether a Nyquist multiplexing process for multiplexing symbols at a rate equal to or lower than the Nyquist rate or an FTN multiplexing process for multiplexing symbols at a rate faster than the Nyquist rate is performed for each of the plurality of channels; Selecting and executing at least one of a switching process for switching the channel on which the Nyquist multiplexing process has been performed to perform the FTN multiplexing process, and a change process for changing the compression ratio of the channel on which the FTN multiplexing process has been performed to a compression ratio that can secure the required bandwidth and then performing the FTN multiplexing process again; transmitting traffic to the receiver via the channel on which the switching process or the change process has been performed; Preferably, the wireless communication method includes:

[0012] The fourth aspect is as follows: A wireless communication program to be executed by a transmitter that wirelessly communicates with a receiver using a plurality of channels, On the transmitter, A process of determining whether a necessary bandwidth is secured for the plurality of channels as a whole; a process of determining whether a Nyquist multiplexing process for multiplexing symbols at a rate equal to or lower than the Nyquist rate or an FTN multiplexing process for multiplexing symbols at a rate higher than the Nyquist rate is performed for each of the plurality of channels when it is determined that the necessary bandwidth is not secured; a selection process for selecting and executing at least one of a switching process for switching the channel on which the Nyquist multiplexing process has been performed to perform the FTN multiplexing process, and a change process for changing the compression ratio of the channel on which the FTN multiplexing process has been performed to a compression ratio that can secure the required bandwidth and then performing the FTN multiplexing process again; transmitting traffic to the receiver via the channel on which the switching or changing process has been performed; It is preferable that the program includes a program for executing the above. Effect of the Invention

[0013] According to the first to fourth aspects of the present disclosure, it is possible to provide a wireless communication system, a transmitter, a wireless communication method, and a wireless communication program capable of expanding a channel bandwidth. [Brief description of the drawings]

[0014] [Figure 1] 1 is a configuration example of a wireless communication system according to a first embodiment of the present disclosure. [Diagram 2] 1 is a block diagram showing a detailed configuration example of a wireless communication system according to a first embodiment of the present disclosure. [Diagram 3] FIG. 2 is a schematic diagram illustrating a transmission method determination process performed by a transmitter according to the first embodiment of the present disclosure. [Figure 4] 4 is a flowchart of a process executed by a transmitter according to the first embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present disclosure will be described with reference to the drawings. The same or corresponding components are designated by the same reference numerals, and repeated description may be omitted.

[0016] First embodiment 1 is a configuration example of a wireless communication system 100 according to a first embodiment of the present disclosure. The wireless communication system 100 includes a transmitter 110 and a receiver 120. The transmitter 110 and the receiver 120 perform wireless communication using a plurality of channels 10.

[0017] When the necessary bandwidth can be secured, the transmitter 110 preferentially executes a process of multiplexing symbols at a rate equal to or lower than the Nyquist rate (hereinafter referred to as Nyquist multiplexing). Furthermore, the transmitter 110 transmits traffic to the receiver 120 via the channel 10 that has been subjected to Nyquist multiplexing. This makes it possible to transmit traffic while avoiding inter-symbol interference.

[0018] On the other hand, when the necessary bandwidth cannot be secured by the Nyquist multiplexing process, the transmitter 110 executes a process of multiplexing symbols at a rate faster than the Nyquist rate so as to obtain a predetermined compression ratio (hereinafter referred to as FTN multiplexing process). That is, the transmitter 110 performs symbol multiplexing by FTN. Furthermore, the transmitter 110 transmits traffic to the receiver 120 via the channel 10 that has been subjected to the FTN multiplexing process. This allows for high signal compression.

[0019] In addition, the channels that have been subjected to FTN multiplexing processing and the channels that have been subjected to Nyquist multiplexing processing may be multiplexed by the transmitter 110 according to a multiplexing number determined for each of them. This enables large-capacity transmission.

[0020] The receiver 120 receives the traffic from the transmitter 110 .

[0021] 2 is a block diagram showing a detailed configuration example of the wireless communication system 100 according to the first embodiment of the present disclosure. In the transmitter 110, the interface unit 111 receives traffic from an upper layer or another device. The abnormality detection unit 117 detects a channel failure based on the communication quality of the channel 10.

[0022] The transmission method determination unit 112 performs a determination process to determine whether the necessary bandwidth is secured for the entire plurality of channels 10. If the necessary bandwidth is not secured, the transmission method determination unit 112 further executes a transmission method determination process to determine whether to apply Nyquist multiplexing or FTN multiplexing for each of the plurality of channels 10.

[0023] The switch 113 outputs traffic to at least one of the first signal processing unit 114 and the second signal processing unit 115 .

[0024] The first signal processing unit 114 performs the above-mentioned Nyquist multiplexing process. The second signal processing unit 115 performs the above-mentioned FTN multiplexing process based on the compression ratio determined by the transmission method determination process. The transmitting unit 116 transmits traffic through a channel that has been subjected to the Nyquist multiplexing process or the FTN multiplexing process.

[0025] In the receiver 120, the receiving unit 121 receives traffic transmitted from the transmitter 110. The first signal processing unit 122 performs signal processing on the traffic originating from the channel subjected to Nyquist multiplexing. The second signal processing unit 123 performs signal processing on the traffic originating from the channel subjected to FTN multiplexing. The interface unit 124 transmits the traffic to an upper layer or another device.

[0026] 3 is a schematic diagram illustrating a transmission method determination process by the transmitter 110 according to the first embodiment of the present disclosure. The transmitter 110 performs Nyquist multiplexing processing with a modulation method of 16QAM for all seven channels 10. Each of the multiple channels 10 has a bandwidth of 150 Mbps. This ensures a required bandwidth of 1 Gbps for the multiple channels 10 as a whole. Note that the number of channels 10, the bandwidth of each of the multiple channels 10, and the required bandwidth are merely examples.

[0027] However, a failure occurs in the first channel 11 and the second channel 12, and the necessary bandwidth cannot be secured for the entire channel 10.

[0028] In the transmission method determination process, if it is determined that the necessary bandwidth can be secured by increasing the modulation level (hereinafter referred to as the level) in the Nyquist multiplexing process, the Nyquist multiplexing process is adopted.

[0029] In the example of Fig. 3, the transmitter 110 increases the number of signal levels from 16QAM to 64QAM. As a result, the bandwidth of each of the channels 10 except for the failed channel 10 is expanded to 200 Mbps. This allows the channels 10 as a whole to maintain a bandwidth of 1 Gbps or more.

[0030] However, a failure then occurs in the third channel 13, and the necessary bandwidth cannot be secured for the entire channel 10.

[0031] In the transmission method determination process, if the required bandwidth cannot be secured by increasing the number of signal levels in the Nyquist multiplexing process, the FTN multiplexing process is adopted.

[0032] In addition, cases where the required bandwidth cannot be secured by raising the number of values ​​include cases where there is no number of values ​​higher than the current number of values. It also includes cases where there is a number of values ​​higher than the current number of values, but it cannot be changed due to restrictions such as C / N. It also includes cases where it is possible to change to a number of values ​​higher than the current number, but the required bandwidth cannot be secured for the entire plurality of channels 10 even if the number of values ​​is changed to a higher number.

[0033] In the example of Fig. 3, the transmitter 110 switches the symbol multiplexing method from Nyquist multiplexing to FTN multiplexing. The compression ratio is 2.5 and the modulation method is 8PSK. As a result, the bandwidth is expanded to 250Mbps in each of the multiple channels 10 except for the failed channel 10. Even if the range of Nyquist multiplexing is not sufficient, the necessary bandwidth can be secured by switching to FTN multiplexing.

[0034] However, this time a failure occurs in the fourth channel 14, and the necessary bandwidth cannot be secured for the entire channel 10.

[0035] In the transmission method determination process, the compression rate in the FTN multiplexing process is determined so that the necessary bandwidth can be secured for the entire channel 10.

[0036] In the example of Fig. 3, the transmitter 110 changes the compression ratio from 2.5 to 3.5. As a result, the bandwidth of each of the multiple channels 10 except for the failed channel 10 is expanded to 350 Mbps. This ensures a bandwidth of 1 Gbps or more for all the channels 10.

[0037] In this manner, in the present disclosure, when the necessary bandwidth can be secured, Nyquist multiplexing is preferentially performed to realize high-quality transmission. When it is necessary to secure the necessary bandwidth, the Nyquist multiplexing is switched to FTN multiplexing. In the FTN multiplexing, the compression rate is determined so that the necessary bandwidth can be secured for the entire channel 10. This makes it possible to realize optimal control for securing the necessary bandwidth.

[0038] 3, the process executed by the transmitter 110 has been described by taking as an example a case where a failure occurs in the channel 10. However, the above process is also effective in cases where the number of channels 10 is intentionally reduced in order to improve the frequency compression ratio. In other words, it is possible to improve the frequency utilization efficiency and contribute to reducing power consumption.

[0039] 4 is a flowchart of a process executed by the transmitter 110 according to the first embodiment of the present disclosure. First, a determination process is executed (step S01). If it is determined that the necessary band is secured, it is determined whether Nyquist multiplexing or FTN multiplexing has been performed on each of the multiple channels 10 (step S02). For channels on which Nyquist multiplexing has been performed, the current Nyquist multiplexing process is performed (step S03). For channels on which FTN multiplexing has been performed, the current FTN multiplexing process is performed (step S04). Furthermore, traffic is transmitted to the receiver 120 (step S05).

[0040] On the other hand, even if it is not determined that the necessary bandwidth is secured, it is determined whether Nyquist multiplexing or FTN multiplexing has been performed on each of the multiple channels 10 (step S06). For the channel 10 on which Nyquist multiplexing has been performed, it is determined whether there is a multi-level number that can secure the necessary bandwidth (step S07). If there is a multi-level number that can secure the necessary bandwidth, the current multi-level number is changed to that multi-level number (step S08). Then, the process proceeds to step S03.

[0041] On the other hand, if there is no multi-level number that can secure the necessary bandwidth, the compression rate in the FTN multiplexing process is set to the initial value (step S09). Then, the process proceeds to step S04. This causes the process to switch from the Nyquist multiplexing process to the FTN multiplexing process.

[0042] On the other hand, for the channel 10 determined in step S06 to have been subjected to FTN multiplexing processing, it is further determined whether or not there is a compression rate that can secure the necessary bandwidth (step S10). If there is a compression rate that can secure the necessary bandwidth, the current compression rate is changed to that compression rate (step S11). Then, the process proceeds to step S04. On the other hand, if there is no compression rate that can secure the necessary bandwidth, the current compression rate is not changed and the process proceeds directly to step S04.

[0043] The processes performed by the transmitter 110 and the receiver 120 may be executed by a communication program using a computer having a CPU and memory and storing a program in the memory. Alternatively, the processes may be executed by a communication program using an integrated circuit such as an FPGA (Field Programmable Gate Array). The communication program may be provided by being recorded on a storage medium, or may be provided through a network.

[0044] As described above, according to the present disclosure, it is possible to provide a wireless communication system, a transmitter, a wireless communication method, and a wireless communication program that are capable of expanding the channel bandwidth.

[0045] <Variation 1> In addition, as long as the necessary bandwidth can be secured, the transmitter 110 may change the compression ratio to slow down the symbol multiplexing rate according to the communication quality of the multiple channels 10. This makes it possible to reduce inter-symbol interference in the channels 10 that have been subjected to FTN multiplexing processing.

[0046] <Variation 2> In the above description, when there is no multi-level number that can secure the necessary band, the Nyquist multiplexing process is switched to the FTN multiplexing process. However, even when there is a multi-level number that can secure the necessary band, the transmitter 110 may switch from the Nyquist multiplexing process to the FTN multiplexing process. By quickly switching to the FTN multiplexing process when it is determined that the necessary band is not secured, a quick response is possible. That is, the transmitter 110 may select and execute at least one of the process of switching to the FTN multiplexing process for the channel on which the Nyquist multiplexing process has been applied, and the process of changing the compression rate of the channel on which the FTN multiplexing process has been applied to a compression rate that can secure the necessary band.

[0047] <Variation 3> The present disclosure is not limited to the above-described embodiment, and various modifications can be made in the implementation stage without departing from the spirit of the present disclosure. In addition, the embodiments may be implemented in appropriate combination, and in that case, the combined effects can be obtained. [Explanation of symbols]

[0048] 10 channel, 11 first channel, 12 second channel, 13 third channel, 14 fourth channel, 100 wireless communication system, 110 transmitter, 111 interface unit, 112 transmission method determination unit, 113 switching unit, 114 first signal processing unit, 115 second signal processing unit, 116 transmission unit, 117 abnormality detection unit, 120 receiver, 121 receiving unit, 122 first signal processing unit, 123 second signal processing unit, 124 interface unit

Claims

1. A transmitter and a receiver for wireless communication using a plurality of channels, The transmitter includes: A process of determining whether a necessary bandwidth is secured for the plurality of channels as a whole; a process of determining whether a Nyquist multiplexing process for multiplexing symbols at a rate equal to or lower than the Nyquist rate or an FTN multiplexing process for multiplexing symbols at a rate higher than the Nyquist rate is performed for each of the plurality of channels when it is determined that the necessary bandwidth is not secured; a selection process for selecting and executing at least one of a switching process for switching the channel on which the Nyquist multiplexing process has been performed to perform the FTN multiplexing process, and a change process for changing the compression rate of the channel on which the FTN multiplexing process has been performed to a compression rate that can secure the required bandwidth and then performing the FTN multiplexing process again; transmitting traffic to the receiver via the channel on which the switching or changing process has been performed; A wireless communication system configured to:

2. In the selection process, the transmitter The method is further configured to execute a process of determining whether or not there is a multi-value number capable of securing the necessary band in the channel on which the Nyquist multiplexing process has been performed, If there is a multi-level number that can secure the required band, the current multi-level number is changed to the multi-level number; The wireless communication system according to claim 1 , wherein the switching process is executed when there is no multi-level number capable of securing the necessary band.

3. 3. The wireless communication system according to claim 1, wherein the transmitter further executes a process of changing a compression ratio so as to slow down the rate in a range in which the necessary bandwidth can be secured, in accordance with communication qualities of the plurality of channels.

4. 3. The wireless communication system according to claim 1, wherein the transmitter is further configured to perform a process of channel multiplexing between channels on which the FTN multiplexing process has been performed and between channels on which the Nyquist multiplexing process has been performed.

5. A transmitter that wirelessly communicates with a receiver using a plurality of channels, A process of determining whether a necessary bandwidth is secured for the plurality of channels as a whole; a process of determining whether a Nyquist multiplexing process for multiplexing symbols at a rate equal to or lower than the Nyquist rate or an FTN multiplexing process for multiplexing symbols at a rate higher than the Nyquist rate is performed for each of the plurality of channels when it is determined that the necessary bandwidth is not secured; a selection process for selecting and executing at least one of a switching process for switching the channel on which the Nyquist multiplexing process has been performed to perform the FTN multiplexing process, and a change process for changing the compression rate of the channel on which the FTN multiplexing process has been performed to a compression rate that can secure the required bandwidth and then performing the FTN multiplexing process again; transmitting traffic to the receiver via the channel on which the switching or changing process has been performed; A transmitter configured to execute the steps of:

6. In the selection process, The method is further configured to execute a process of determining whether or not there is a multi-value number capable of securing the necessary band in the channel on which the Nyquist multiplexing process has been performed, If there is a multi-level number that can secure the required band, the current multi-level number is changed to the multi-level number; The transmitter according to claim 5 , wherein the switching process is executed when there is no multi-level number capable of securing the required band.

7. A transmitter that wirelessly communicates with a receiver using a plurality of channels, determining whether a necessary bandwidth is secured for the plurality of channels as a whole; if it is not determined that the necessary bandwidth is secured, determining whether Nyquist multiplexing processing, which multiplexes symbols at a rate equal to or lower than the Nyquist rate, or FTN multiplexing processing, which multiplexes symbols at a rate faster than the Nyquist rate, is performed for each of the plurality of channels; Selecting and executing at least one of a switching process for switching the channel on which the Nyquist multiplexing process has been performed to perform the FTN multiplexing process, and a change process for changing the compression rate of the channel on which the FTN multiplexing process has been performed to a compression rate that can secure the required bandwidth and then performing the FTN multiplexing process again; transmitting traffic to the receiver via the channel on which the switching process or the change process has been performed; A wireless communication method comprising:

8. A wireless communication program to be executed by a transmitter that wirelessly communicates with a receiver using a plurality of channels, On the transmitter, A process of determining whether a necessary bandwidth is secured for the plurality of channels as a whole; a process of determining whether a Nyquist multiplexing process for multiplexing symbols at a rate equal to or lower than the Nyquist rate or an FTN multiplexing process for multiplexing symbols at a rate higher than the Nyquist rate is performed for each of the plurality of channels when it is determined that the necessary bandwidth is not secured; a selection process for selecting and executing at least one of a switching process for switching the channel on which the Nyquist multiplexing process has been performed to perform the FTN multiplexing process, and a change process for changing the compression rate of the channel on which the FTN multiplexing process has been performed to a compression rate that can secure the required bandwidth and then performing the FTN multiplexing process again; transmitting traffic to the receiver via the channel on which the switching or changing process has been performed; A program for wireless communication, comprising a program for executing the above.

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