Wireless communication system, wireless communication method, and wireless device

Abstract

An embodiment relates to a wireless communication system in which data is transferred from a transmission device to a reception device using a plurality of frequency channels. The transmission device comprises: a retirement control unit that implements a retirement control to retire some of the traffic of one or more frequency channels in which the BER has reached a predetermined value to one or more other frequency channels in which the BER has not reached the predetermined value; and a reduction control unit that implements a reduction control to reduce either the number of levels of multilevel modulation or encoding rate, or both, with respect to traffic that remains after the retirement control unit has retired some traffic from the traffic of the frequency channel in which the BER has reached the predetermined value.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system, a wireless communication method, and a wireless device. [Background technology]

[0002] In wireless communication systems that use microwave communication, it is necessary to reduce the effects of radio interference and fading. Known techniques for reducing the effects of radio interference and fading include space diversity, polarization diversity, and frequency diversity.

[0003] For example, Non-Patent Document 1 discloses the configuration of space diversity for constructing a wireless access system suitable for medium- to long-distance marine radio wave propagation in remote islands and the like, and the effects of polarization diversity. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "Report on the Investigation and Study for the Construction of Wireless Access Systems Suitable for Medium- to Long-Distance Marine Propagation in Remote Islands, etc.", Ministry of Internal Affairs and Communications, Kyushu Bureau of Telecommunications, "Report of the Investigation and Study Committee for FY2008" (Main Text), March 2009 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Non-Patent Document 1 requires multiple pieces of radio equipment (antennas, waveguides, branching filters, receivers, etc.) to achieve diversity. Furthermore, when performing frequency diversity, a redundant frequency channel to which to switch is required, and when bit errors occur simultaneously in multiple frequency channels, the effects of fading and the like may not be reduced.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a wireless communication system, a wireless communication method, and a wireless device that can efficiently reduce traffic bit errors even when radio interference, fading, etc. occur. [Means for solving the problem]

[0007] A wireless communication system according to one aspect of the present invention is a wireless communication system that transmits data from a transmitting device to a receiving device using multiple frequency channels, and the transmitting device is characterized by having an evacuation control unit that performs evacuation control to evacuate a portion of traffic on one or more frequency channels whose BER has reached a predetermined value to one or more other frequency channels whose BER has not reached the predetermined value, and a reduction control unit that performs reduction control to reduce at least one of the number of multi-levels of multi-level modulation and the coding rate for traffic remaining after the evacuation control unit has evacuated a portion of the traffic from the frequency channels whose BER has reached the predetermined value.

[0008] Furthermore, a wireless communication method according to one aspect of the present invention is a wireless communication method for transmitting data from a transmitting device to a receiving device using a plurality of frequency channels, characterized in that it includes an evacuation control step for performing evacuation control to evacuate a portion of traffic on one or more frequency channels whose BER has reached a predetermined value to one or more other frequency channels whose BER has not reached the predetermined value, and a reduction control step for performing reduction control to reduce at least one of the number of multi-levels of multi-level modulation and the coding rate for traffic remaining after evacuating a portion of traffic from the frequency channels whose BER has reached the predetermined value.

[0009] Furthermore, a wireless device according to one aspect of the present invention is a wireless device that transmits data using multiple frequency channels, and is characterized by having: an evacuation control unit that performs evacuation control to evacuate part of the traffic of one or more frequency channels whose BER has reached a predetermined value to one or more other frequency channels whose BER has not reached the predetermined value; and a reduction control unit that performs reduction control to reduce at least one of the number of multi-levels of multi-level modulation and the coding rate for traffic remaining after the evacuation control unit has evacuated part of the traffic from the frequency channels whose BER has reached the predetermined value. [Effects of the Invention]

[0010] According to the present invention, even if radio interference or fading occurs, bit errors in traffic can be reduced efficiently. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram illustrating functions of a transmitting device according to an embodiment. [Figure 3] FIG. 2 is a functional block diagram illustrating functions of a receiving device. [Figure 4] FIG. 2 is a diagram illustrating a schematic example of a plurality of user signals transmitted from a transmitting device to a receiving device. [Figure 5] (a) is a diagram illustrating each wireless channel when interference or fading occurs on frequency channel X after a transmitting device starts transmitting data. (b) is a diagram illustrating each wireless channel when a transmitting device performs evacuation control. (c) is a diagram illustrating each wireless channel when a transmitting device performs reduction control. [Figure 6](a) is a diagram illustrating each wireless channel when interference or fading occurs on frequency channels X and Y after a transmitting device starts transmitting data. (b) is a diagram illustrating each wireless channel when a transmitting device performs evacuation control. (c) is a diagram illustrating each wireless channel when a transmitting device performs reduction control. [Figure 7] FIG. 10 is a diagram illustrating an example of operation of a transmitting device according to an embodiment. [Figure 8] FIG. 10 is a diagram illustrating a schematic example of a plurality of user signals transmitted from a transmitting device to a receiving device in a modified example of a wireless communication system. [Figure 9] (a) is a diagram illustrating each wireless channel when interference or fading occurs on frequency channels X and Y after a transmitting device starts transmitting data. (b) is a diagram illustrating each wireless channel when a transmitting device performs evacuation control. (c) is a diagram illustrating each wireless channel when a transmitting device performs reduction control. [Figure 10] 1A is a diagram illustrating a schematic example of a plurality of user signals transmitted by a transmitting device without dividing the traffic of each user, and FIG. 1B is a diagram illustrating a schematic example of each wireless channel after the transmitting device has performed evacuation control and reduction control. [Figure 11] 1A is a diagram illustrating a plurality of user signals that are transmitted by a transmitting device by dividing the traffic of each user, and FIG. 1B is a diagram illustrating each wireless channel after the transmitting device has performed evacuation control and reduction control. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of a wireless communication system will be described below with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of a wireless communication system 1 according to an embodiment. As shown in Fig. 1, the wireless communication system 1 includes a transmitting device 2 and a receiving device 3, and is configured so that the transmitting device 2 and the receiving device 3 perform wireless communication such as microwave band land fixed communication.

[0013] For example, a transmitting device 2 uses multiple frequency channels to transmit multiple user signals (data) to a receiving device 3. The transmitting device 2 and the receiving device 3 each have a function of transmitting and receiving data such as multiple user signals, and each can also operate as a relay radio device (radio device).

[0014] 2 is a functional block diagram illustrating functions of a transmitting device 2 according to an embodiment. As shown in Fig. 2, the transmitting device 2 includes, for example, an interface (I / F) unit 21, a frame processing unit 22, four modulation units 23 each corresponding to a frequency channel, four RF (radio frequency) units 24 each corresponding to a frequency channel, an antenna 25, and a control unit 26.

[0015] The I / F unit 21 is a user interface that acquires, for example, three user signals A, B, and C and outputs them to the frame processing unit 22. The user signals A, B, and C are, for example, signals output by three different user terminals (not shown), and include data of different categories such as calls, videos, text, files, and photos.

[0016] The frame processing unit 22 performs buffering, bit division, mapping, packetization, etc. on the user signal output by the I / F unit 21 to generate a predetermined frame, and outputs the generated frame to each modulation unit 23.

[0017] Each of the modulation units 23 performs multi-level modulation on the user signal output by the frame processing unit 22 for each frequency channel, and outputs the multi-level modulated user signal to the RF unit 24. Furthermore, each of the modulation units 23 has a function of changing the modulation method of the multi-level modulation under the control of the control unit 26.

[0018] Each RF unit 24 has a transmitting unit 240 and a receiving unit 242. The transmitting unit 240 transmits the user signal modulated by the modulating unit 23 to the receiving device 3 for each frequency channel via the antenna 25. The receiving unit 242 receives the signal transmitted by the receiving device 3 via the antenna 25 and outputs it to the control unit 26.

[0019] For example, the receiving unit 242 receives a BER (Bit Error Rate) transmitted by a receiving device 3 (described later) and outputs the received BER to the control unit 26. The receiving unit 242 also receives a CN ratio (C / N: Carrier-to-Noise Ratio) transmitted by a receiving device 3 (described later) and outputs the received CN ratio to the control unit 26.

[0020] The control unit 26 has, for example, an evacuation control unit 260 and a reduction control unit 262, and controls each unit constituting the transmission device 2. The control unit 26 also performs control for synchronizing with the reception device 3.

[0021] The evacuation control unit 260 performs evacuation control, for example, to evacuate part of the traffic of one or more frequency channels in which the BER of data transmitted from the transmitting device 2 to the receiving device 3 has reached a predetermined value to one or more other frequency channels in which the BER has not reached the predetermined value.

[0022] At this time, the evacuation control unit 260 performs evacuation control based on the BER received by the receiving unit 242. Furthermore, the evacuation control unit 260 performs control to cancel the evacuation control when the CN ratio received by the receiving unit 242 returns from less than a predetermined value to a predetermined value or more.

[0023] The reduction control unit 262 performs reduction control to reduce at least one of the number of multi-levels of the multi-level modulation and the coding rate for traffic remaining after the evacuation control unit 260 evacuates some of the traffic from the traffic of a frequency channel whose BER has reached a predetermined value.

[0024] For example, the reduction control unit 262 reduces the number of multi-levels from 64QAM (Quadrature Amplitude Modulation) to 16QAM. That is, the control unit 26 can reduce the C / N required to ensure BER quality, improve resistance to interference and fading, and reduce bit errors.

[0025] Furthermore, the reduction control unit 262 can strengthen error correction and reduce bit errors by reducing the coding rate.

[0026] The reduction control unit 262 performs reduction control based on the CN ratio received by the receiving unit 242. Furthermore, the reduction control unit 262 performs control to cancel the reduction control when the CN ratio received by the receiving unit 242 returns from less than a predetermined value to a predetermined value or more.

[0027] Fig. 3 is a functional block diagram illustrating the functions of the receiving device 3. As shown in Fig. 3, the receiving device 3 includes, for example, an antenna 31, four RF (radio frequency) units 32 each corresponding to a frequency channel, four demodulation units 33 each corresponding to a frequency channel, a frame processing unit 34, an interface (I / F) unit 35, and a control unit 36.

[0028] Each RF unit 32 includes, for example, a receiving unit 320, a transmitting unit 322, and a CNR detecting unit 324.

[0029] The receiving unit 320 receives each of the multiple user signals transmitted by the transmitting device 2 for each frequency channel via the antenna 31, and outputs the received user signals to the demodulating unit 33. The receiving unit 320 also outputs the signal transmitted by the transmitting device 2 to the control unit 36.

[0030] The transmitting unit 322 transmits a signal (data) to the transmitting device 2 via the antenna 31. For example, the transmitting unit 322 transmits to the transmitting device 2 a CN ratio (described later) detected by the CN ratio detecting unit 324 and a BER detected by a BER detecting unit 330 (described later).

[0031] The CN ratio detection unit 324 detects the CN ratio of each of a plurality of frequency channels for a signal transmitted from the transmission device 2 to the reception device 3, and outputs the detected CN ratio to the control unit 36. The control unit 36 outputs the CN ratio detected by the CN ratio detection unit 324 to the transmission unit 322.

[0032] Each demodulator 33 has a BER detector 330, demodulates the user signal received by the RF unit 32 for each frequency channel, and outputs the demodulated user signal to the frame processor 34. The demodulator 33 performs demodulation corresponding to the evacuation control and reduction control of the transmitter 2 under the control of the controller 36.

[0033] The BER detection unit 330 detects the BER of each of a plurality of frequency channels for a signal transmitted from the transmission device 2 to the reception device 3, and outputs the detected BER to the control unit 36. The control unit 36 outputs the BER detected by the BER detection unit 330 to the transmission unit 322.

[0034] The frame processing unit 34 performs buffering, bit combining, demapping, and the like on the user signals output from the demodulation units 33 to generate predetermined frames, and outputs the generated frames to the I / F unit 35.

[0035] The I / F unit 35 is a user interface that acquires, for example, three user signals A, B, and C output by the frame processing unit 34 and outputs them to subsequent stages.

[0036] The control unit 36 controls each unit constituting the receiving device 3. The control unit 36 also performs control to respond to the evacuation control and reduction control performed by the transmitting device 2, and control to synchronize with the transmitting device 2. That is, the control unit 36 controls the process in which the receiving unit 320 receives a signal from the transmitting device 2 and the process in which the transmitting unit 322 transmits a signal to the transmitting device 2.

[0037] In addition, each function possessed by the above-mentioned transmitting device 2 and receiving device 3 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0038] For example, the transmitting device 2 and the receiving device 3 according to an embodiment can be realized using a computer and a program, and the program can be recorded on a storage medium or provided via a network.

[0039] Next, a more specific description will be given of an example of the operation of the wireless communication system 1. Fig. 4 is a diagram illustrating a schematic example of a plurality of user signals transmitted from the transmitting device 2 to the receiving device 3. The transmitting device 2 transmits user signals for users A, B, and C, for example.

[0040] Specifically, the transmitting device 2 allocates three user signals individually to, for example, three frequency channels X, Y, and Z, and simultaneously transmits them to the receiving device 3. That is, the transmitting device 2 allocates wireless packets of each user individually to frequency channels X, Y, and Z, and starts transmitting data to the receiving device 3. At this time, it is assumed that there is idle traffic O in each of the frequency channels X, Y, and Z.

[0041] Fig. 5 is a diagram illustrating each wireless channel when interference or fading occurs in one of the channels when the transmitting device 2 transmits data to the receiving device 3. Fig. 5(a) is a diagram illustrating each wireless channel when interference or fading occurs in frequency channel X after the transmitting device 2 starts transmitting data. Fig. 5(b) is a diagram illustrating each wireless channel when the transmitting device 2 performs evacuation control. Fig. 5(c) is a diagram illustrating each wireless channel when the transmitting device 2 performs reduction control.

[0042] 5(a), if interference or fading occurs on frequency channel X after transmitting device 2 starts transmitting data, and if transmitting device 2 does not perform traffic control, a bit error may occur in the data of user A transmitted on frequency channel X. In this case, no bit error occurs in the data of user B transmitted on frequency channel Y and the data of user C transmitted on frequency channel Z.

[0043] First, as shown in FIG. 5(b), when interference or fading occurs in frequency channel X, the transmitting device 2 performs evacuation control to evacuate part of the traffic of user A transmitted through frequency channel X to the vacant traffic O of each of frequency channels Y and Z (STEP 1).

[0044] That is, the transmitting device 2 allocates a part of the traffic of user A transmitted on frequency channel X to each of frequency channels Y and Z, thereby reducing the traffic volume on frequency channel X.

[0045] Next, as shown in FIG. 5(c), the transmitting device 2 performs reduction control on the traffic remaining on the frequency channel X, reducing at least one of the number of multi-levels in the multi-level modulation and the coding rate (STEP 2).

[0046] In other words, because the traffic volume on frequency channel X is reduced, the transmitting device 2 can perform robust communication and reduce bit errors even if at least one of the number of modulation levels and the coding rate is reduced.

[0047] Fig. 6 is a diagram illustrating each wireless channel when interference or fading occurs simultaneously on multiple channels when the transmitting device 2 transmits data to the receiving device 3. Fig. 6(a) is a diagram illustrating each wireless channel when interference or fading occurs on frequency channels X and Y after the transmitting device 2 starts transmitting data. Fig. 6(b) is a diagram illustrating each wireless channel when the transmitting device 2 performs evacuation control. Fig. 6(c) is a diagram illustrating each wireless channel when the transmitting device 2 performs reduction control.

[0048] 6(a), if interference or fading occurs on frequency channels X and Y after transmitter 2 starts transmitting data, and transmitter 2 does not perform traffic control, bit errors may occur in the data of users A and B transmitted on frequency channels X and Y. In this case, no bit errors occur in the data of user C transmitted on frequency channel Z.

[0049] First, as shown in FIG. 6(b), when interference or fading occurs on frequency channels X and Y, the transmitting device 2 performs evacuation control to evacuate a portion of the traffic of users A and B transmitted on frequency channels X and Y to vacant traffic O on frequency channel Z (STEP 1).

[0050] That is, the transmitting device 2 allocates a portion of each of the traffic of users A and B transmitted on frequency channels X and Y to frequency channel Z, thereby reducing the traffic volume on each of frequency channels X and Y.

[0051] Next, as shown in FIG. 6(c), the transmitting device 2 performs reduction control for the traffic remaining in each of the frequency channels X and Y, reducing at least one of the number of multi-levels of the multi-level modulation and the coding rate (STEP 2).

[0052] In other words, because the traffic volume of each of the frequency channels X and Y is reduced, the transmitting device 2 can perform robust communication and reduce bit errors even if at least one of the number of modulation levels and the coding rate is reduced.

[0053] Fig. 7 is a diagram showing an example of the operation of the transmitting device 2. As shown in Fig. 7, the transmitting device 2 acquires C / Ns (normal C / Ns) in a state without interference or fading for all wireless channels (S100). Specifically, the transmitting device 2 receives the C / Ns of all wireless channels detected by the receiving device 3.

[0054] In step 102 (S102), the transmitting device 2 determines whether the BER of any wireless channel has deteriorated, and if it determines that the BER has deteriorated (S102: Yes), it proceeds to processing of S104, and if it determines that the BER has not deteriorated (S102: No), it continues processing of S100.

[0055] In step 104 (S104), the transmitting device 2 determines whether there is available capacity in the traffic of the wireless channel without BER degradation, and if it determines that there is available capacity (S104: Yes), it proceeds to processing of S106, and if it determines that there is no available capacity (S104: No), it continues processing of S100.

[0056] In step 106 (S106), the transmitting device 2 evacuates (allocates) part of the traffic of the wireless channel where interference or fading is occurring (interfered wireless channel) to a wireless channel without BER degradation. That is, the transmitting device 2 performs evacuation control.

[0057] In step 108 (S108), the transmitting device 2 changes the modulation scheme for the interfered wireless channel to a modulation scheme with a smaller number of multi-level values, thereby reducing the coding rate. That is, the transmitting device 2 performs reduction control.

[0058] In step 110 (S110), the transmitting device 2 receives the C / N of each wireless channel from the receiving device 3, and thereby monitors the C / N of each wireless channel.

[0059] In step 112 (S112), the transmitting device 2 determines whether the C / N of the wireless channel in which the BER had deteriorated has recovered to the normal C / N, and if it determines that it has recovered (S112: Yes), it proceeds to processing of S114, and if it determines that it has not recovered (S112: No), it returns to processing of S110.

[0060] In step 114 (S114), the transmitting device 2 restores the modulation scheme and coding rate for the wireless channel in which interference or fading has occurred. That is, the transmitting device 2 increases the number of modulation levels and the coding rate.

[0061] In step 116 (S116), the transmitting device 2 cancels the evacuation (returns the allocation) of part of the traffic of the wireless channel where interference or fading has occurred.

[0062] In this way, in the wireless communication system 1 according to one embodiment, the transmitting device 2 performs the evacuation control and reduction control, so that even if radio interference, fading, or the like occurs, bit errors in traffic can be reduced efficiently.

[0063] Next, a modification of the wireless communication system 1 will be described.

[0064] In a variant of the wireless communication system 1, the transmitting device 2 may include a dividing unit that divides each of the data of the multiple users into bit units, a distributed processing unit that distributes each of the data of the multiple users divided by the dividing unit so that the data of the multiple users is evenly contained in each of the multiple frequency channels, and a transmitting unit that transmits the data of the multiple users distributed by the distributed processing unit for each frequency channel.

[0065] In addition, in a modified example of the wireless communication system 1, the receiving device 3 may include a receiving unit that receives the data of multiple users transmitted by the transmitting unit of the transmitting device 2 for each frequency channel, an extracting unit that extracts each of the data of the multiple users received by the receiving unit on a bit-by-bit basis from each of the multiple frequency channels, and a reproducing unit that combines and reproduces each of the data of the multiple users extracted by the extracting unit for each user.

[0066] 8 is a diagram illustrating a schematic example of a plurality of user signals transmitted from a transmitting device 2 to a receiving device 3 in a modification of the wireless communication system 1. The transmitting device 2 transmits user signals of users A, B, and C, for example, by equally using frequency channels X, Y, and Z.

[0067] Specifically, the transmitting device 2 divides the traffic of each of the users A, B, and C into bits, mixes the traffic of each of the users A, B, and C in time-division wireless packets, and equally allocates the wireless packets to each of the frequency channels X, Y, and Z.

[0068] 9A and 9B are diagrams illustrating each wireless channel when interference or fading occurs simultaneously on multiple channels when a transmitting device 2 transmits data to a receiving device 3 in a modified example of the wireless communication system 1. FIG. 9A is a diagram illustrating each wireless channel when interference or fading occurs on frequency channels X and Y after the transmitting device 2 starts transmitting data. FIG. 9B is a diagram illustrating each wireless channel when the transmitting device 2 performs evacuation control. FIG. 9C is a diagram illustrating each wireless channel when the transmitting device 2 performs reduction control.

[0069] 9(a), if interference or fading occurs on frequency channels X and Y after transmitter 2 starts transmitting data, and transmitter 2 does not perform traffic control, bit errors may occur in the data of users A, B, and C transmitted on frequency channels X and Y. In this case, no bit errors will occur in the data of users A, B, and C transmitted on frequency channel Z.

[0070] First, as shown in FIG. 9(b), when interference or fading occurs on frequency channels X and Y, the transmitting device 2 performs evacuation control to evacuate a portion of the traffic of users A, B, and C transmitted on frequency channels X and Y to vacant traffic O on frequency channel Z (STEP 1).

[0071] It should be noted that the idle traffic O on frequency channel Z may not have enough capacity to accommodate a portion of the traffic of users A, B, and C transmitted on frequency channels X and Y.

[0072] Here, the transmitting device 2 allocates a portion of each of the traffic of users A, B, and C transmitted through frequency channels X and Y to frequency channel Z, thereby reducing the traffic volume of each of frequency channels X and Y.

[0073] Next, as shown in FIG. 9(c), the transmitting device 2 performs reduction control for the traffic remaining in each of the frequency channels X and Y, reducing at least one of the number of multi-levels of the multi-level modulation and the coding rate (STEP 2).

[0074] Because the traffic volume of each of the frequency channels X and Y is reduced, the transmitting device 2 can perform robust communication and reduce bit errors even if at least one of the number of modulation levels and the coding rate is reduced.

[0075] Next, the effect of the modified example of the wireless communication system 1 in reducing traffic bit errors when there is insufficient free traffic capacity on the wireless channel will be described with reference to FIGS.

[0076] Fig. 10 is a diagram illustrating each radio channel when the transmitting device 2 assigns each user's traffic to a frequency channel without dividing the traffic. Fig. 10(a) is a diagram illustrating a plurality of user signals transmitted by the transmitting device 2 without dividing the traffic of each user. Fig. 10(b) is a diagram illustrating each radio channel after the transmitting device 2 has performed evacuation control and reduction control.

[0077] If there is insufficient free traffic capacity in the wireless channel, and interference or fading occurs in frequency channels X and Y, as shown in FIG. 10, the transmitting device 2 may cause a bit error in the data of user A in frequency channel X and a bit error in the data of user B in frequency channel Y even after performing the evacuation control and reduction control.

[0078] In other words, even if the transmitting device 2 evacuates part of the traffic to frequency channel Z after interference or fading occurs on frequency channels X and Y, if there is not enough available traffic O on frequency channel Z, there will be more bit errors in the data of users A and B that are also transmitted on frequency channels X and Y than in the data of user C that is transmitted only on frequency channel Z.

[0079] Fig. 11 is a diagram illustrating each wireless channel when the transmitting device 2 divides the traffic of each user and assigns it to each frequency channel. Fig. 11(a) is a diagram illustrating a plurality of user signals that the transmitting device 2 divides the traffic of each user and transmits. Fig. 11(b) is a diagram illustrating each wireless channel after the transmitting device 2 has performed evacuation control and reduction control.

[0080] 11, the transmitting device 2 divides the traffic of each user and distributes it equally to each frequency channel before interference or fading occurs in frequency channels X and Y. In this case, even if frequency channel Z, which is the destination for the traffic, does not have a sufficient capacity for vacant traffic O, the transmitting device 2 can average out the bit errors of multiple users A, B, and C by performing evacuation control and reduction control, regardless of the degree of bit errors or the excess or shortage of vacant traffic.

[0081] That is, by dividing the traffic of each user and allocating it to each frequency channel (FIG. 11), the transmitting device 2 can reduce the BER of users A and B compared to when the traffic of each user is allocated to frequency channels without being divided (FIG. 10). That is, the transmitting device 2 can reduce the BER per user. [Explanation of symbols]

[0082] 1 Wireless communication system, 2 Transmitter, 3 Receiver, 21 I / F unit, 22 Frame processing unit, 23 Modulator, 24 RF unit, 25 Antenna, 26 Control unit, 31 Antenna, 32 RF unit, 33 Demodulator, 34 Frame processing unit, 35 I / F unit, 36 Control unit, 240 Transmitter, 242 Receiver, 260 Evacuation control unit, 262 Reduction control unit, 320 Receiver, 322 Transmitter, 324 CN ratio detector, 330 BER detector

Claims

1. In a wireless communication system in which data is transmitted from a transmitting device to a receiving device using a plurality of frequency channels, The transmitting device an evacuation control unit that performs evacuation control to evacuate part of traffic of one or more frequency channels whose BER has reached a predetermined value to one or more other frequency channels whose BER has not reached the predetermined value; a reduction control unit that performs reduction control to reduce at least one of the number of multi-levels of multi-level modulation and the coding rate for traffic remaining after the evacuation control unit evacuates part of the traffic from the traffic of the frequency channel whose BER has reached a predetermined value; A wireless communication system comprising:

2. The receiving device a BER detection unit that detects a BER for each of a plurality of frequency channels; a transmitting unit that transmits the BER detected by the BER detecting unit to the transmitting device; and The transmitting device a receiving unit that receives the BER transmitted by the transmitting unit; and The evacuation control unit performing the evacuation control based on the BER received by the receiving unit; 2. The wireless communication system according to claim 1, wherein:

3. The receiving device a CN ratio detection unit that detects a CN ratio for each of a plurality of frequency channels; a transmitting unit that transmits the CN ratio detected by the CN ratio detecting unit to the transmitting device; and The transmitting device a receiving unit that receives the CN ratio transmitted by the transmitting unit; and The reduction control unit performing the reduction control based on the CN ratio received by the receiving unit; 2. The wireless communication system according to claim 1, wherein:

4. The evacuation control unit When the CN ratio received by the receiving unit returns from less than a predetermined value to a predetermined value or more, control is performed to cancel the evacuation control. The reduction control unit When the CN ratio received by the receiving unit returns from being less than a predetermined value to being equal to or greater than a predetermined value, the reduction control is cancelled.

4. The wireless communication system according to claim 3, wherein:

5. A wireless communication method for transmitting data from a transmitting device to a receiving device using a plurality of frequency channels, an evacuation control step of performing evacuation control to evacuate part of traffic of one or more frequency channels whose BER has reached a predetermined value to one or more other frequency channels whose BER has not reached the predetermined value; a reduction control step of performing reduction control to reduce at least one of the number of multi-levels of multi-level modulation and the coding rate for traffic remaining after evacuating part of the traffic of the frequency channel whose BER has reached a predetermined value; A wireless communication method comprising:

6. In a wireless device that transmits data using a plurality of frequency channels, an evacuation control unit that performs evacuation control to evacuate part of traffic of one or more frequency channels whose BER has reached a predetermined value to one or more other frequency channels whose BER has not reached the predetermined value; a reduction control unit that performs reduction control to reduce at least one of the number of multi-levels of multi-level modulation and the coding rate for traffic remaining after the evacuation control unit evacuates part of the traffic from the traffic of the frequency channel whose BER has reached a predetermined value; A wireless device comprising:

7. A receiving unit that receives the BER of each of a plurality of frequency channels from another wireless device. and The evacuation control unit performing the evacuation control based on the BER received by the receiving unit; 7. The wireless device according to claim 6,

8. a receiving unit that receives the CN ratios of each of a plurality of frequency channels from another wireless device; and The reduction control unit performing the reduction control based on the CN ratio received by the receiving unit; 7. The wireless device according to claim 6,

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