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

Abstract

To provide a radio communications system capable of executing a transmission control corresponded to deterioration of a communication quality of a channel in an FTN transmission.SOLUTION: A radio communications system of the present disclosure, comprises a transmitter and a receptor that perform a radio communication by using a plurality of channels. The transmitter executes FTN multiplex processing for multiplying a symbol with a rate that is higher than that of a Nyquist rate in a channel for transmitting a traffic as using a traffic of which a priority is a low priority. In addition, the traffic is transmitted to the receptor via the channel to which the FTN multiplex processing is executed. The transmitter switches a method of the symbol multiplex so that it becomes the rate or less than the Nyquist rate in the case where it is recognized that communication quality of the channel to which the FTN multiplex processing is executed is deteriorated. Or, a compression ratio is changed so that the rate in the FTN multiplex processing becomes delay.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 technology 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, the above-mentioned method cannot implement transmission control that corresponds to deterioration of the communication quality of the channel.

[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 implementing transmission control in response to deterioration of the communication quality of a channel.

[0006] A second object of the present disclosure is to provide a transmitter capable of implementing transmission control in response to deterioration of the communication quality of a channel.

[0007] A third object of the present disclosure is to provide a wireless communication method capable of implementing transmission control in response to deterioration of channel communication quality.

[0008] A fourth object of the present disclosure is to provide a wireless communication program capable of implementing transmission control in response to deterioration of the communication quality of a channel. [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: determining whether the traffic to be transmitted is high priority or low priority; For the low priority traffic, a FTN multiplexing process for multiplexing symbols at a rate faster than a Nyquist rate in the channel carrying the low priority traffic; transmitting the low priority traffic to the receiver via the FTN multiplexed channel; A process of acquiring communication quality of the channel subjected to the FTN multiplexing process; A process of determining whether the communication quality has deteriorated; configured to run If it is determined that the communication quality has deteriorated, It is preferable that the wireless communication system is configured to further perform a selection process for selecting and executing at least one of a switching process for switching the symbol multiplexing method so that the rate is equal to or lower than the Nyquist rate, and a change process for changing the compression rate so as to slow down the rate in the FTN multiplexing process, for a channel subjected to the FTN multiplexing process.

[0010] The second aspect is as follows: A transmitter that wirelessly communicates with a receiver using a plurality of channels, determining whether the traffic to be transmitted is high priority or low priority; For the low priority traffic, a FTN multiplexing process for multiplexing symbols at a rate faster than a Nyquist rate in the channel carrying the low priority traffic; transmitting the low priority traffic to the receiver via the FTN multiplexed channel; A process of acquiring communication quality of the channel subjected to the FTN multiplexing process; A process of determining whether the communication quality has deteriorated; configured to run If it is determined that the communication quality has deteriorated, It is preferable that the system is further configured to perform a selection process that selects and executes at least one of a switching process that switches the symbol multiplexing method so that the rate becomes equal to or lower than the Nyquist rate, and a change process that changes the compression rate so as to slow down the rate in the FTN multiplexing process, for a channel that has been subjected to the FTN multiplexing process.

[0011] The third aspect is as follows: A transmitter that wirelessly communicates with a receiver using a plurality of channels, determining whether the traffic to be transmitted is high priority traffic or low priority traffic; For the low priority traffic, performing FTN multiplexing processing for multiplexing symbols at a rate faster than a Nyquist rate in the channel transmitting the low priority traffic; transmitting the low priority traffic to the receiver via the FTN multiplexed channel; Obtaining communication quality of the channel subjected to the FTN multiplexing process; determining whether the communication quality has deteriorated; Including, If it is determined that the communication quality has deteriorated, It is preferable that the wireless communication method further includes selecting and executing at least one of a switching process for switching a symbol multiplexing method so that the rate is equal to or lower than the Nyquist rate, and a change process for changing a compression rate so as to slow down the rate in the FTN multiplexing process, for a channel subjected to the FTN multiplexing process.

[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, determining whether the traffic to be transmitted is high priority or low priority; For the low priority traffic, a FTN multiplexing process for multiplexing symbols at a rate faster than a Nyquist rate in the channel carrying the low priority traffic; transmitting the low priority traffic to the receiver via the FTN multiplexed channel; A process of acquiring communication quality of the channel subjected to the FTN multiplexing process; A process of determining whether the communication quality has deteriorated; If it is determined that the communication quality has deteriorated, At least one of a switching process for switching a symbol multiplexing method so that the rate is equal to or lower than the Nyquist rate for the channel on which the FTN multiplexing process has been performed, and a change process for changing a compression rate so as to slow down the rate in the FTN multiplexing process. A selection process for selecting and executing 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 that can implement transmission control in response to deterioration of channel communication quality. [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 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] The transmitter 110 periodically measures the bandwidth used in transmitting traffic, and performs a bandwidth usage acquisition process to acquire the actual bandwidth usage.

[0018] Furthermore, the transmitter 110 performs a necessary bandwidth determination process to allocate a necessary bandwidth for each traffic priority based on the actual bandwidth usage. Note that the traffic priority is determined based on the QoS color (Quality of Service color, hereinafter referred to as QoS) implemented in the frames that constitute the traffic.

[0019] Furthermore, a multiplexing number determination process is executed to determine the number of multiplexed channels 10 for each priority level based on the required bandwidth.

[0020] Furthermore, the transmitter 110 performs channel multiplexing according to the determined multiplexing number.

[0021] Furthermore, the transmitter 110 performs symbol multiplexing on each channel 10 according to the determined required bandwidth, where the symbol multiplexing method is changed depending on whether the channel 10 is carrying high-priority traffic or low-priority traffic.

[0022] For the channel 10 carrying high-priority traffic, the transmitter 110 performs a process of multiplexing symbols at a rate equal to or lower than the Nyquist rate (hereinafter referred to as Nyquist multiplexing), which enables transmission of high-priority traffic while avoiding inter-symbol interference.

[0023] On the other hand, for channels 10 transmitting low-priority traffic, the transmitter 110 executes a process of multiplexing symbols at a rate faster than the Nyquist rate so as to achieve a predetermined compression ratio (hereinafter referred to as FTN multiplexing). That is, the transmitter 110 multiplexes symbols using FTN. This allows for high signal compression, enabling large-capacity transmission for low-priority traffic. The compression ratio in the FTN multiplexing process is determined based on the communication quality of each channel 10.

[0024] Hereinafter, the channel 10 that has been subjected to Nyquist multiplexing processing will be referred to as a Nyquist channel 11. Similarly, the channel 10 that has been subjected to FTN multiplexing processing will be referred to as an FTN channel 12.

[0025] Transmitter 110 transmits high priority traffic to receiver 120 over Nyquist channel 11. Similarly, transmitter 110 transmits low priority traffic to receiver 120 over FTN channel 12.

[0026] The receiver 120 receives the traffic from the transmitter 110 .

[0027] 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, an interface unit 111 receives traffic from an upper layer or another device. A measurement unit 117 measures the communication quality of the channel 10. The communication quality is, for example, a BER (Bit Error Rate).

[0028] The transmission method determination unit 112 executes the above-mentioned bandwidth usage acquisition process, necessary bandwidth determination process, and multiplex number determination process, and also executes compression rate change process for determining the compression rate in FTN multiplexing process based on the communication quality measurement result.

[0029] The switching unit 113 checks the priority level of the traffic to be transmitted, and outputs the traffic to the first signal processing unit 114 if it is high priority, or to the second signal processing unit 115 if it is low priority.

[0030] The first signal processing unit 114 executes the above-mentioned Nyquist multiplexing process. The second signal processing unit 115 executes the above-mentioned FTN multiplexing process based on the compression ratio determined by the transmission method determination unit 112. The transmitting unit 116 transmits traffic through the Nyquist channel 11 or the FTN channel 12.

[0031] In the receiver 120, the receiving unit 121 receives the traffic transmitted from the transmitter 110. The first signal processing unit 122 performs signal processing on the traffic originating from the Nyquist channel 11. The second signal processing unit 123 performs signal processing on the traffic originating from the FTN channel 12. The interface unit 124 transmits the traffic to an upper layer or to another device.

[0032] 3 is a schematic diagram illustrating a process performed by the transmitter 110 according to the first embodiment of the present disclosure. The transmitter 110 estimates the magnitude of inter-symbol interference in the FTN channel 12 based on the measurement result of communication quality. When it is confirmed that the inter-symbol interference has worsened due to the influence of multipath fading or the like, the transmitter 110 changes the compression rate in the FTN multiplexing process to a slower symbol multiplexing rate. This makes it possible to reduce the inter-symbol interference. In the example of FIG. 3, the transmitter 110 initially sets the compression rate of the FTN multiplexing process to 2, but changes it to 1.5 as the inter-symbol interference worsens.

[0033] If the inter-symbol interference continues to worsen even after changing the compression ratio, the transmitter 110 changes the compression ratio further in the direction of slowing the symbol multiplexing rate. However, when the compression ratio reaches 1, this means that the compression ratio cannot be changed further in the direction of slowing the symbol multiplexing rate in the FTN multiplexing process. Therefore, the transmitter 110 stops the FTN multiplexing process and switches to performing Nyquist multiplexing on channels transmitting low-priority traffic, and transmits the signal.

[0034] In this manner, in the present disclosure, the transmitter 110 changes the compression ratio in the FTN multiplexing process in a direction that slows down the symbol multiplexing rate in response to the deterioration of inter-symbol interference in the FTN channel 12. Also, when the compression ratio reaches 1, the transmitter 110 switches from FTN transmission to Nyquist transmission. This allows low-priority traffic to be transmitted in a manner that reduces the effects of inter-symbol interference.

[0035] 4 is a flowchart of a process executed by the transmitter 110 according to the first embodiment of the present disclosure. First, a used band acquisition process is executed (step S01). Next, a required band determination process is executed (step S02). Next, a multiplexing number determination process is executed to perform channel multiplexing (step S03). Furthermore, it is determined whether the traffic to be transmitted is high priority or low priority (step S04).

[0036] If the traffic is high priority, Nyquist multiplexing is performed (step S05), and the traffic is then transmitted to the receiver 120 (step S06).

[0037] If the traffic is low priority, FTN multiplexing processing is performed (step S07). Furthermore, the traffic is transmitted to receiver 120 (step S08). Furthermore, the communication quality of FTN channel 12 is measured, and the magnitude of inter-symbol interference is estimated (step S09). Furthermore, it is determined whether the estimated inter-symbol interference has improved, worsened, or remained unchanged compared to the previous measurement (step S10). If no change is observed in the magnitude of inter-symbol interference, the process returns to step S09.

[0038] On the other hand, if an improvement in inter-symbol interference is recognized, the current compression rate is changed in the subsequent compression rate change process so that the symbol multiplexing rate becomes faster (step S11), and the process returns to step S09.

[0039] On the other hand, if the deterioration of the inter-symbol interference is recognized, it is determined whether the compression rate can be changed so as to slow down the symbol multiplexing rate (step S12). If the change is possible, in the subsequent compression rate change process, the current compression rate is changed in the direction in which the symbol multiplexing rate becomes slower (step S13). Then, the process returns to step S09. On the other hand, if the compression rate cannot be changed any further, the process proceeds to step S05 and switches to Nyquist multiplexing process.

[0040] As described above with reference to the flowchart, the present disclosure realizes optimal transmission control according to communication quality even for low-priority traffic.

[0041] 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.

[0042] 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 implementing transmission control in response to deterioration of the communication quality of a channel.

[0043] <Variation 1> As described above, in the necessary bandwidth determination process, the necessary bandwidth is determined according to the traffic priority based on the actual bandwidth usage. However, the necessary bandwidth does not have to be determined based on the actual bandwidth usage. For example, the necessary bandwidth may be determined by machine learning or the like. Furthermore, the necessary bandwidth for each of high-priority traffic and low-priority traffic may be a predetermined bandwidth value.

[0044] <Variation 2> As described above, the transmitter 110 estimates the magnitude of inter-symbol interference in the FTN channel 12 based on the measurement results of communication quality. However, if it is recognized that there is a clear correlation between the measured communication quality such as BER and the magnitude of inter-symbol interference, it is not necessary to estimate the magnitude of inter-symbol interference. In this case, in step S10 of FIG. 4, it is sufficient to determine the state of time change based on communication quality instead of inter-symbol interference. In this case, the same effect as described above can be obtained.

[0045] <Variation 3> In the above description, the transmitter 110 determines whether the compression rate can be changed so as to slow down the symbol multiplexing rate, and when the compression rate cannot be changed any further, the transmitter 110 may switch from FTN transmission to Nyquist transmission. However, even when the compression rate can still be changed, the transmitter 110 may switch from FTN transmission to Nyquist transmission. By quickly switching to Nyquist transmission when it is recognized that the inter-symbol interference has worsened, a quick response is possible. The transmitter 110 may execute at least one of a process of switching the symbol multiplexing method to Nyquist multiplexing processing and a process of changing the compression rate so as to slow down the symbol multiplexing rate for a channel that has been subjected to FTN multiplexing processing.

[0046] Variation 4 Note that the communication quality of the FTN channel 12 does not necessarily have to be measured by the transmitter 110. For example, the above-mentioned effect can be obtained by the transmitter 110 acquiring the communication quality measured by the receiver 120.

[0047] <Variation 5> 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 Nyquist channel, 12 FTN 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 transmitting unit, 117 measuring 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: determining whether the traffic to be transmitted is high priority or low priority; For the low priority traffic, an FTN multiplexing process for multiplexing symbols at a rate faster than the Nyquist rate in the channel carrying the low priority traffic; transmitting said low priority traffic to said receiver via said FTN multiplexed channel; A process of acquiring communication quality of the channel subjected to the FTN multiplexing process; A process of determining whether the communication quality has deteriorated; configured to run If it is determined that the communication quality has deteriorated, The wireless communication system is further configured to execute a selection process for selecting and executing at least one of a switching process for switching a symbol multiplexing method so that the rate is equal to or lower than the Nyquist rate, and a change process for changing a compression rate so as to slow down the rate in the FTN multiplexing process, for a channel subjected to the FTN multiplexing process.

2. The transmitter includes: a Nyquist multiplexing process for multiplexing symbols at a rate equal to or lower than the Nyquist rate; transmitting the high priority traffic to the receiver over the Nyquist multiplexed channel; The wireless communication system of claim 1 further configured to perform:

3. The wireless communication system according to claim 1 or 2, wherein the transmitter is further configured to execute a process of changing the compression ratio so that the rate becomes faster when it is determined that the communication quality has improved.

4. In the selection process, the transmitter The method is further configured to perform a process of determining whether the compression ratio can be changed to reduce the rate; If it is determined that the change is possible, the change process is executed; The wireless communication system according to claim 1 , further comprising: a step of: executing the switching process when it is determined that the change is not possible.

5. The transmitter includes: A process of allocating a required bandwidth for each traffic priority; determining the number of multiplexed channels for each of the priorities based on the required bandwidth; a process of multiplexing the channels on which the FTN multiplexing process has been performed and the channels on which the Nyquist multiplexing process has been performed in accordance with the determined multiplexing numbers; The wireless communication system of claim 2 further configured to perform:

6. A transmitter that wirelessly communicates with a receiver using a plurality of channels, determining whether the traffic to be transmitted is high priority or low priority; For the low priority traffic, an FTN multiplexing process for multiplexing symbols at a rate faster than the Nyquist rate in the channel carrying the low priority traffic; transmitting said low priority traffic to said receiver via said FTN multiplexed channel; A process of acquiring communication quality of the channel subjected to the FTN multiplexing process; A process of determining whether the communication quality has deteriorated; configured to run If it is determined that the communication quality has deteriorated, The transmitter is further configured to perform a selection process for selecting and executing at least one of a switching process for switching a symbol multiplexing method so that the rate is equal to or lower than the Nyquist rate, and a modification process for changing a compression rate so as to slow down the rate in the FTN multiplexing process, for a channel subjected to the FTN multiplexing process.

7. A transmitter that wirelessly communicates with a receiver using a plurality of channels, determining whether the traffic to be transmitted is high priority traffic or low priority traffic; For the low priority traffic, performing FTN multiplexing processing for multiplexing symbols at a rate faster than a Nyquist rate in the channel carrying the low priority traffic; transmitting the low priority traffic to the receiver over the FTN multiplexed channel; acquiring a communication quality of the channel on which the FTN multiplexing process has been performed; determining whether the communication quality has deteriorated; Including, If it is determined that the communication quality has deteriorated, The wireless communication method further includes selecting and executing at least one of a switching process for switching a symbol multiplexing method so that the rate is equal to or lower than a Nyquist rate, and a change process for changing a compression rate in the FTN multiplexing process so as to slow down the rate, for a channel on which the FTN multiplexing process has been performed.

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, determining whether the traffic to be transmitted is high priority or low priority; For the low priority traffic, an FTN multiplexing process for multiplexing symbols at a rate faster than the Nyquist rate in the channel carrying the low priority traffic; transmitting said low priority traffic to said receiver via said FTN multiplexed channel; A process of acquiring communication quality of the channel subjected to the FTN multiplexing process; A process of determining whether the communication quality has deteriorated; If it is determined that the communication quality has deteriorated, At least one of a switching process for switching a symbol multiplexing method so that the rate is equal to or lower than the Nyquist rate for a channel on which the FTN multiplexing process has been performed, and a change process for changing a compression rate in the FTN multiplexing process so that the rate is slowed down. A selection process for selecting and executing A program for wireless communication, comprising a program for executing the above.

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