Wireless communication system and wireless communication device

Abstract

To provide a technique that can reduce unusable channels.SOLUTION: A wireless communication system includes a first wireless communication device, and a second wireless communication device that selectively uses three or more types of channels divided by the frequency division multiplexing method. The first wireless communication device and the second wireless communication device perform wireless communication by the time division multiplexing method, based on remaining combination groups after excluding combination groups that include avoidance groups from a plurality of combination groups obtained by combining three or more types of channels.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to a wireless communication system , and wireless communication devices thereof.

Background Art

[0002] In a wireless communication system in which wireless communication is performed between one or more ground devices and a plurality of mobile stations such as a train wireless system, it has been proposed to adopt a frequency division multiplexing method that divides communication paths into a plurality of channels according to frequencies. The divided communication paths are called channels, and a channel is defined by a frequency.

[0003] Generally, when the frequencies of a plurality of channels pass through a non-linear circuit on a line, intermodulation occurs and unwanted signals (hereinafter referred to as unwanted waves) are generated at frequencies different from those frequencies. The frequency of this unwanted wave may be the same as the frequency of the channel used for the signal to be communicated (hereinafter referred to as the desired wave). In such a case, the D / U ratio, which is used to evaluate the influence of noise on the system, that is, the ratio of the level of the desired wave (D) to the level of the unwanted wave (U) deteriorates, and stable communication cannot be achieved.

[0004] Therefore, a technique has been proposed to suppress the deterioration of the D / U ratio by allocating channels for the desired wave so that a channel having the same frequency as the frequency of the unwanted wave is not used as the channel for the desired wave (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] <统一编号 However, in conventional wireless communication systems, channels with the same frequency as unwanted signals remain unused. Therefore, if, for example, a function is pre-assigned to that channel, that function cannot be used at all, which presents a problem.

[0007] Therefore, this disclosure has been made in view of the above-mentioned problems and aims to provide a technology that can reduce the number of unusable channels. [Means for solving the problem]

[0008] The wireless communication system according to this disclosure comprises a first wireless communication device and a second wireless communication device capable of wirelessly communicating with the first wireless communication device using three or more channels divided by a frequency division multiplexing scheme. A group consisting of two types of channels and one type of channel that is generated as an unwanted wave by intermodulation when the two types of channels are input to a nonlinear circuit is defined as an avoidance group. The first wireless communication device and the second wireless communication device perform wireless communication using a time division multiplexing scheme based on the remaining combination groups obtained by combining the three or more types of channels, excluding the combination group that includes the avoidance group. [Effects of the Invention]

[0009] According to this disclosure, the first and second wireless communication devices perform wireless communication using a time-division multiplexing scheme based on the remaining combination groups obtained by combining three or more available channels, excluding the combination group that includes the avoidance group. With such a configuration, the number of unusable channels can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram showing the configuration of the wireless communication system according to Embodiment 1. [Figure 2] This is a block diagram showing the configuration of the ground equipment according to Embodiment 1. [Figure 3] A flowchart showing the operation of the wireless communication system according to Embodiment 1. [Figure 4] This is a diagram showing the configuration of the wireless communication system according to Embodiment 2. [Figure 5] This is a flowchart showing the operation of the wireless communication system according to Embodiment 2. [Figure 6] This diagram shows the configuration of a wireless communication system as shown in the modified example. [Modes for carrying out the invention]

[0011] <Embodiment 1> The wireless communication system according to this first embodiment is a wireless communication system applicable to, for example, a train radio system, and comprises a ground device which is a first wireless communication device and a mobile station which is a second wireless communication device. The mobile station is capable of wirelessly communicating with the ground device by selectively using three or more channels divided by a frequency multiplexing scheme.

[0012] Figure 1 shows the configuration of a wireless communication system according to this first embodiment. The wireless communication system in Figure 1 comprises a ground device BS and three different mobile stations M1, M2, and M3. The mobile stations M1, M2, and M3 are capable of wireless communication with the ground device BS by selectively using three types of channels CH1, CH2, and CH3, which are divided using a frequency multiplexing scheme.

[0013] In Figure 1, mobile station M1 performs function K1 communication with ground device BS by transmitting desired wave D1 using channel CH1 assigned to frequency F1. Mobile station M2 performs function K2 communication with ground device BS by transmitting desired wave D2 using channel CH2 assigned to frequency F2. Mobile station M3 performs function K3 communication with ground device BS by transmitting desired wave D3 using channel CH3 assigned to frequency F3. Note that channels and frequencies have a corresponding relationship, and in the following explanation, they may not be distinguished from each other.

[0014] Generally, when signals of two types of frequencies (channels) pass through a non-linear circuit such as an amplifier on the line between a mobile station and a ground device, unwanted waves are generated at frequencies different from the two types of frequencies due to intermodulation. In the example of FIG. 1, an unwanted wave U3 is generated at the same frequency as the frequency F3 of the desired wave D3 due to the intermodulation between the frequency F1 and the frequency F2.

[0015] Hereinafter, an unwanted wave generated by the intermodulation between a certain frequency Fx and a certain frequency Fy is denoted as U(Fx,Fy), and its frequency is denoted as F(Fx,Fy). In the example of FIG. 1, it is expressed as U3 = U(F1,F2) and F3 = F(F1,F2).

[0016] In the example of FIG. 1, the frequency F3 of the desired wave D3 of the mobile station M3 is the same as the frequency F3 of the unwanted wave U3. Therefore, when the level of the desired wave D3 is not sufficiently larger than the level of the unwanted wave U3, communication using the desired wave D3 cannot be performed without being interfered by the unwanted wave U3. This is equivalent to the fact that the function K3 cannot be used in the example of FIG. 1 where the function K3 is assigned to the desired wave D3. In FIG. 1, since both the desired wave D3 and the unwanted wave U3 have the frequency F3 and the frequency F3 = F(F1,F2), if the frequencies F1, F2, and F3 are used simultaneously, there is a possibility that the desired wave D3 cannot be communicated due to interference by the unwanted wave U3.

[0017] To solve this problem, in the wireless communication system according to Embodiment 1, a time division multiplexing method is adopted in units of frequency (channel) combinations so that the frequencies F1, F2, and F3 are not used simultaneously. This will be described below.

[0018] FIG. 2 is a block diagram showing the configuration of the ground device BS according to Embodiment 1. The ground device BS in FIG. 2 includes a CPU (Central Processing Unit) section 1, a storage section 2, a transmission section 3, and a reception section 4. The transmission section 3 transmits a radio signal to the mobile station, and the reception section 4 receives a radio signal from the mobile station. As will be described below, the CPU section 1 controls the transmission section 3 and the reception section 4 based on the frequency of the radio signal received by the reception section 4 from the mobile station and the database stored in the storage section 2, thereby controlling the wireless communication between the ground device and the mobile station.

[0019] In a wireless communication system that divides channels by frequency division multiplexing, since the types of frequencies used are generally determined in advance, the avoidance group can be calculated in advance. Therefore, in Embodiment 1, a group of two types of frequencies and one type of frequency that is generated as an unwanted wave by intermodulation when the two types of frequencies are input to a non-linear circuit is defined as an avoidance group.

[0020] In Embodiment 1, an avoidance group consisting of a certain desired wave and an unwanted wave that is generated by intermodulation and interferes with the desired wave is pre-databaseized and defined in the storage section 2 of FIG. 2. Note that the avoidance group may be defined by the CPU section 1 appropriately calculating using mathematical formulas without being pre-databaseized. Assuming that n is the number of types of frequencies in the wireless communication system, and the avoidance group is denoted as B = {Fx, Fy, Fz | x, y, z = any of 1 to n}, in the example of FIG. 1, the avoidance group is denoted as B = {F1, F2, F3}.

[0021] The CPU section 1 obtains a plurality of combination groups by combining three types of frequencies that can be selectively used by the mobile station. In the example of FIG. 1, the CPU section 1 obtains {F1, F2, F3}, {F1, F2}, {F2, F3}, and {F3, F1} as a plurality of combination groups. In the plurality of combination groups in this example, {F1}, {F2}, and {F3} that do not form a group are excluded from all combinations of the frequencies F1, F2, and F3.

[0022] The CPU unit 1 determines the remaining combination groups by removing the combination group containing the avoidance group from the multiple combination groups. Then, the ground equipment and mobile stations perform wireless communication using time-division multiplexing based on the remaining combination groups, under the control of the CPU unit 1. In the example in Figure 1, the remaining combination groups are {F1,F2}, {F3,F1}, and {F2,F3}, so the ground equipment BS and mobile stations M1, M2, and M3 perform wireless communication using time-division multiplexing based on {F1,F2}, {F3,F1}, and {F2,F3}.

[0023] Specifically, at time T1, only channels CH1 and CH2, i.e., frequencies F1 and F2, are used; at time T2, only channels CH3 and CH1, i.e., frequencies F3 and F1, are used; and at time T3, only channels CH2 and CH3, i.e., frequencies F2 and F3, are used. Therefore, frequencies F1, F2, and F3 are not used simultaneously at any given time, and consequently, functions K1, K2, and K3 are used for two-thirds of the time between time T1 and time T3. As a result, there are no channels or functions that are unavailable within the time frame shown in Figure 1.

[0024] Note that the time intervals T1, T2, and T3 are not limited to the example in Figure 1, but are appropriately set as parameters by the wireless communication system and stored in the memory unit 2. Also, in the example in Figure 1, the weighting of {F1,F2}, {F3,F1}, and {F2,F3} are the same, and their usage frequencies are the same, but this is not limited to this. For example, if functions K1 and K2 are more important than function K3, the weighting of {F1,F2} may be made greater than the weighting of {F3,F1} and {F2,F3}, and the usage frequency of {F1,F2} may be greater than the usage frequency of {F3,F1} and {F2,F3}.

[0025] Figure 3 is a flowchart illustrating the operation of the wireless communication system according to this embodiment 1. While Figure 1 described an example where three frequencies are available, this section describes an example where ten frequencies are available. Note that the following operation can be applied if three or more frequencies are available.

[0026] In step S1, the CPU unit 1 collects information on the frequencies used by each mobile station using the receiving unit 4, and designates the set of these frequencies as usage group A. If all mobile stations use frequencies F1, F2, F3, F5, F7, F9, and F10, the usage group A for those frequencies is written as A={F1,F2,F3,F5,F7,F9,F10}.

[0027] In step S2, the CPU unit 1 compares usage group A, which includes the frequencies to be used, with avoidance group B, which includes frequencies that should not be used simultaneously and is stored in the memory unit 2. In the example in Figure 3, the number of types of frequencies in the wireless communication system is n=10, and the avoidance group B consists of B1={F1,F2,F3}, B2={F1,F4,F6}, B3={F3,F7,F9}, B4={F4,F6,F10}, B5={F4,F8,F9}, B6={F5,F7,F10}, B7={F5,F9,F10}, B8={F6,F8,F9}, B9={F7,F8,F9}, and B10={F8,F9,F10}. In other words, there are 10 avoidance groups B.

[0028] In step S3, the CPU unit 1 extracts avoidance groups from avoidance group B that are included in usage group A, i.e., avoidance groups such that A∋B, as avoidance group C. In Figure 3, B1={F1,F2,F3}, B3={F3,F7,F9}, B6={F5,F7,F10}, and B7={F5,F9,F10} are included in usage group A={F1,F2,F3,F5,F7,F9,F10}, so B1=C1, B3=C3, B6=C6, and B7=C7.

[0029] If there are many avoidance groups B, the processing in steps S1 to S3 is performed, which simplifies the processing in the next step, S4.

[0030] In step S4, the ground equipment and mobile station, under the control of the CPU unit 1, perform wireless communication using a time-division multiplexing scheme based on the remaining combination groups obtained by combining the frequencies of usage group A, excluding the combination group that includes avoidance group C.

[0031] In the example in Figure 3, if we combine, for example, four different frequencies from the usage group A = {F1, F2, F3, F5, F7, F9, F10}, we can obtain 35 (= 7C4) possible combination groups. Of these combination groups, the 14 combination groups that include avoidance group C are {F1,F2,F3,F5}, {F1,F2,F3,F7}, {F1,F2,F3,F9}, {F1,F2,F3,10}, {F1,F3,F7,F9}, {F2,F3,F7,F9}, {F3,F5,F7,F9}, {F3,F7,F9,F10}, {F1,F5,F7,F10}, {F2,F5,F7,F10}, {F3,F5,F7,F10}, {F5,F7,F9,F10}, {F1,F7,F9,F10}, and {F2,F7,F9,F10}. Therefore, the ground equipment and mobile station perform wireless communication using time-division multiplexing based on the remaining combination groups, which are 21 combination groups (=35-14), under the control of the CPU unit 1. In other words, under the control of the CPU unit 1, the frequencies of avoidance groups C1, C3, C6, and C7 are not used simultaneously.

[0032] Here, we have described a case where multiple combination groups can be obtained by combining four types of frequencies from usage group A, but this is not the only case. For example, multiple combination groups may be obtained by combining at least one of the following types of frequencies from usage group A: 6, 5, 4, 3, or 2.

[0033] After step S4, processing returns to step S1, and the CPU unit 1 collects information on the frequencies used by each mobile station. The cycle for returning from step S4 to step S1 is appropriately set as a parameter by the wireless communication system and stored in the memory unit 2.

[0034] <Summary of Embodiment 1> According to this embodiment 1, the ground equipment and mobile station perform wireless communication using a time-division multiplexing scheme based on the remaining combination groups obtained by combining three or more available channels, excluding the combination group that includes the avoidance group. With this configuration, the number of unusable channels can be reduced, and therefore, for example, the number of unusable functions can be reduced.

[0035] <Embodiment 2> Figure 4 shows the configuration of the wireless communication system according to this second embodiment. Hereinafter, among the components of this second embodiment, components that are the same as or similar to the components described above will be denoted by the same or similar reference numerals, and the different components will be described mainly.

[0036] The wireless communication system in Figure 4 comprises a ground station BS and four distinct mobile stations M1, M2, M3, and M5. The mobile stations M1, M2, M3, and M5 can communicate wirelessly with the ground station BS by selectively using four channels CH1, CH2, CH3, and CH5, which are divided using a frequency multiplexing scheme.

[0037] Figure 4 shows mobile stations M1 to M3 similar to those in Figure 1. Mobile station M5 performs function K5 communication with ground device BS by transmitting desired wave D5 using channel CH5 assigned to frequency F5. Function K4, which uses channel CH4 assigned to frequency F4, is not used within the time period shown in Figure 4, and therefore desired wave D4 does not exist.

[0038] In the example in Figure 4, similar to the example in Figure 1, an unwanted wave U3=U(F1,F2) with frequency F3=F(F1,F2) is generated, and the frequency F3 of the desired wave D3 of mobile station M3 is the same as the frequency F3 of the unwanted wave U3. Also, an unwanted wave U5=U(F2,F3) with frequency F5=F(F2,F3) is generated, and the frequency F5 of the desired wave D5 of mobile station M5 is the same as the frequency F5 of the unwanted wave U5.

[0039] The ratio of the level of the desired signal (D) to the level of the unwanted signal (U) is denoted as the D / U ratio. Here, "level" corresponds to the signal strength and includes both the input level and the transmission level. Generally, if a desired signal and an unwanted signal have the same frequency, communication of the desired signal is possible if the D / U ratio is higher than the D / U ratio allowed in the wireless communication system's circuit design, and impossible if it is lower.

[0040] The level of unwanted waves, U(Fx,Fy), is uniquely determined by the levels of frequencies Fx and Fy passing through the nonlinear circuit on the line; the higher the levels of frequencies Fx and Fy, the higher the level of unwanted waves.

[0041] In this second embodiment, the maximum level of one channel is defined to correspond to information about two types of frequencies (channels). Below, we will describe the case where the information about the two types of frequencies Fx and Fy refers to the type of mobile station that uses the two types of frequencies Fx and Fy. In this case, for example, a database is defined in the storage unit 2 of Figure 2 in which the type of mobile station that uses the two types of frequencies Fx and Fy is pre-associated with the maximum level of unwanted waves, which is U(Fx,Fy).

[0042] Generally, in transmissions from a mobile station to a ground device, the signal level fluctuates depending on the mobile station's location. However, if the maximum signal level within the communication range from the mobile station to the ground device is defined in the circuit design, the maximum signal level input to the nonlinear circuit with frequencies Fx and Fy is fixed, and therefore the maximum signal level of unwanted waves can be calculated in advance. Furthermore, there is a correspondence between the type of mobile station and the maximum signal level. For this reason, in this embodiment 2, as described above, a database is defined in which the types of mobile stations using two types of frequencies Fx and Fy are pre-associated with the maximum signal level of unwanted waves, U(Fx,Fy).

[0043] Furthermore, the information regarding the two frequencies Fx and Fy is not limited to the type of mobile station using the two frequencies Fx and Fy; for example, it may be the levels of the two frequencies Fx and Fy themselves. Also, the maximum level of unwanted waves may be determined by appropriately calculating it in the CPU unit 1 using a mathematical formula based on the levels of the two frequencies Fx and Fy.

[0044] Similar to the maximum level, the minimum level input to the nonlinear circuit of the desired wave is generally defined in the circuit design. If the D / U ratio in the tightest case, where the desired wave (D) level is at its minimum and the unwanted wave (U) level is at its maximum, is higher than the minimum D / U ratio in the circuit design, then the unwanted wave will not substantially affect the communication of the desired wave.

[0045] Therefore, in this second embodiment, the CPU unit 1 modifies the avoidance group described in the first embodiment based on the maximum level of one type of channel and the minimum level when a mobile station uses one type of channel, corresponding to information about two types of frequencies. In other words, the CPU unit 1 modifies the avoidance group described in the first embodiment based on the maximum level of unwanted waves and the minimum level of desired waves.

[0046] In the example in Figure 4, an unwanted wave U3=U(F1,F2) with frequency F3=F(F1,F2) is generated, and since the frequency F3 of the desired wave D3 of mobile station M3 is the same as the frequency F3 of the unwanted wave U3, the avoidance group B={F1,F2,F3} is defined. In this example, the D / U ratio between the minimum level when mobile station M3 uses the desired wave D3 frequency F3 and the maximum level of the unwanted wave U3 is higher than the minimum D / U ratio for the line design. For this reason, CPU unit 1 excludes B={F1,F2,F3} from the avoidance group. As a result, at time T1, channels CH1, CH2, CH3, i.e., frequencies F1, F2, F3 are used simultaneously, and functions K1, K2, K3 are available simultaneously.

[0047] On the other hand, in the example in Figure 4, an unwanted wave U5 = U(F2,F3) with frequency F5 = F(F2,F3) is generated, and since the frequency F5 of the desired wave D5 of mobile station M5 and the frequency F5 of the unwanted wave U5 are the same, the avoidance group B = {F2,F3,F5} is defined. In this example, the D / U ratio between the minimum level when mobile station M5 uses the desired wave D5 frequency F5 and the maximum level of the unwanted wave U5 is lower than the minimum D / U ratio for the line design. For this reason, the CPU unit 1 maintains B = {F2,F3,F5} as the avoidance group. As a result, channels CH2, CH3, CH5, i.e., frequencies F2, F3, F5 are not used simultaneously. However, as in Embodiment 1, wireless communication is performed using a time-division multiplexing method, so wireless communication using frequency F5 is performed at times T2 and T3.

[0048] Figure 5 is a flowchart showing the operation of the wireless communication system according to this second embodiment. Here, we will describe an example in which 10 different frequencies are available. Note that if three or more different frequencies are available, the following operation can be applied.

[0049] In step S11, the CPU unit 1 collects information on the frequencies used by each mobile station using the receiving unit 4, and designates this set of frequencies as usage group A. The CPU unit 1 also obtains the maximum level for the nonlinear circuit in the line design that is pre-associated with each type of mobile station in the storage unit 2, and designates this set of maximum levels as level group R. If frequencies F1, F2, F3, F5, F7, F9, and F10 are used, and their respective maximum levels are R1, R2, R3, R5, R7, R9, and R10, then A={F1,F2,F3,F5,F7,F9,F10} and R={R1,R2,R3,R5,R7,R9,R10}.

[0050] In step S12, the CPU unit 1 compares usage group A, which includes the frequencies to be used, with avoidance group B, which includes frequencies that should not be used simultaneously. In Figure 5, avoidance group B is the same as in Embodiment 1, with B1={F1,F2,F3}, B2={F1,F4,F6}, B3={F3,F7,F9}, B4={F4,F6,F10}, B5={F4,F8,F9}, B6={F5,F7,F10}, B7={F5,F9,F10}, B8={F6,F8,F9}, B9={F7,F8,F9}, and B10={F8,F9,F10}.

[0051] In step S13, the CPU unit 1 extracts avoidance groups from avoidance group B that are included in usage group A, i.e., avoidance groups such that A∋B, as avoidance group C. In Figure 5, B1={F1,F2,F3}, B3={F3,F7,F9}, B6={F5,F7,F10}, and B7={F5,F9,F10} are included in usage group A={F1,F2,F3,F5,F7,F9,F10}, so B1=C1, B3=C3, B6=C6, and B7=C7.

[0052] In step S14, the CPU unit 1 obtains the maximum level of unwanted waves (U) from group R for each of the avoidance groups C, and obtains the minimum level of desired waves (D), which is uniquely determined by the system's circuit design, from the memory unit 2 or the like. Then, the CPU unit 1 calculates the D / U ratio from the obtained maximum level of unwanted waves (U) and minimum level of desired waves (D), and extracts the avoidance groups C whose calculated D / U ratio is lower than the minimum D / U ratio in the circuit design as avoidance group E. In Figure 5, for C3={F3,F7,F9}, C6={F5,F7,F10}, and C7={F5,F9,F10}, the calculated D / U ratio is lower than the minimum D / U ratio in the circuit design, so C3=E3, C6=E6, and C7=E7.

[0053] In step S15, the ground equipment and mobile station, under the control of the CPU unit 1, perform wireless communication using time-division multiplexing based on the remaining combination groups obtained by combining the frequencies of usage group A, excluding the combination group containing avoidance group E. In the example in Figure 5, under the control of the CPU unit 1, the frequencies of avoidance groups E3, E6, and E7 are not used simultaneously.

[0054] After step S15, processing returns to step S11, and the CPU unit 1 collects information on the frequencies used by each mobile station. The cycle for returning from step S15 to step S11 is appropriately set as a parameter by the wireless communication system and stored in the memory unit 2.

[0055] <Summary of Embodiment 2> According to this second embodiment, the number of unusable channels can be reduced, similar to the first embodiment. Furthermore, according to this second embodiment, the avoidance group is changed based on the maximum level of one type of unwanted signal channel and the minimum level at which the mobile station uses that type of channel. With this configuration, the number of avoidance groups can be reduced, and thus the number of remaining combination groups for performing wireless communication using time-division multiplexing can be increased.

[0056] <Variation> In the above explanation, the first radio communication device was a ground device and the second radio communication device was a mobile station, but this is not the only explanation. For example, the first radio communication device and the second radio communication device may each be either a ground device or a mobile station.

[0057] Furthermore, in the above explanation, the second radio communication device consisted of multiple mobile stations, each using one channel, but this is not the only option. For example, the second radio communication device could be a single mobile station using multiple channels.

[0058] Furthermore, although the above explanation assumes only one ground device, this is not the only option. For example, as shown in Figure 6, multiple ground devices (ground devices B1 and BS2 in Figure 6) connected to the central device CE via a network may be used. Each ground device (ground device B1 or ground device B1 in Figure 6) may then communicate wirelessly with multiple mobile stations (mobile stations M1, M2 or mobile stations M3, M4 in Figure 6).

[0059] Furthermore, while the above description describes the ground equipment determining or modifying the avoidance group, multiple combination groups, and the remaining combination groups, the mobile station may also determine or modify the avoidance group, multiple combination groups, and the remaining combination groups.

[0060] Furthermore, it is possible to freely combine each embodiment and its variations, or to modify or omit each embodiment and its variations as appropriate. [Explanation of Symbols]

[0061] BS ground equipment, M1,M2,M3,M5 mobile station.

Claims

1. First wireless communication device, A second wireless communication device that can communicate wirelessly with the first wireless communication device uses three or more channels divided by a frequency multiplexing scheme to selectively utilize these channels. Equipped with, A group consisting of two types of channels and one type of channel that is generated as an unwanted wave by intermodulation when the two types of channels are input to a nonlinear circuit is defined as an avoidance group. The first wireless communication device and the second wireless communication device are a wireless communication system that performs wireless communication using a time-division multiplexing scheme based on the remaining combination groups obtained by combining three or more types of channels, excluding the combination group that includes the avoidance group.

2. A wireless communication system according to claim 1, The maximum level of one type of channel is defined to correspond to the information of the two types of channels. A wireless communication system in which at least one of the first wireless communication device and the second wireless communication device modifies the avoidance group based on the maximum level of the one type of channel and the minimum level when the second wireless communication device uses the one type of channel.

3. A wireless communication device capable of wireless communication using three or more channels divided by a frequency multiplexing scheme, A group consisting of two types of channels and one type of channel that is generated as an unwanted wave by intermodulation when the two types of channels are input to a nonlinear circuit is defined as an avoidance group. A wireless communication device that performs wireless communication using a time-division multiplexing scheme based on the remaining combination groups obtained by combining the three or more types of channels, excluding the combination group that includes the avoidance group.

4. A wireless communication device according to claim 3, The maximum level of one type of channel is defined to correspond to the information of the two types of channels. A wireless communication device that modifies the avoidance group based on the maximum level of the one type of channel and the minimum level when using the one type of channel.

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