Radio communications system

Abstract

To provide a technique capable of making radio transmission quality as high as possible.SOLUTION: A radio communications system comprises: first radio communication equipment which redundantly transmits first application data by using first and second radio signals with frequencies different from each other; and second radio communication equipment which includes a receiver executing first processing including performing demodulation and performing a diversity synthesis on the basis of the first and second radio signals, and which acquires the first application data on the basis of the result of the first processing.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system.

Background Art

[0002] In a wireless communication system that performs wireless communication between a base station and a mobile body, a technique for improving wireless transmission quality by increasing the number of receiving antennas to enhance diversity gain is known. However, increasing the number of receiving antennas has a problem that equipment costs and antenna installation space increase. This problem becomes particularly prominent in a wireless communication system using a leaky coaxial cable (LCX).

[0003] Also, a technique for improving wireless transmission quality such as transmission reliability using two wireless waves (that is, two wireless signals having different frequencies) has been proposed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique of Patent Document 1, in either of the two wireless waves, when the wireless line state is poor and data errors occur, it is not an issue to continuously transmit application data between the base station and the mobile body as much as possible. For this reason, in such a case, there has been a problem that the wireless transmission quality deteriorates.

[0006] Therefore, the present disclosure has been made in view of the above problems, and an object thereof is to provide a technique capable of improving wireless transmission quality as much as possible.

Means for Solving the Problems

[0007] The wireless communication system according to the present disclosure includes a first wireless communication device that redundantly transmits first application data using a first wireless signal and a second wireless signal having different frequencies, and a receiver that performs a first process including performing diversity synthesis based on the first wireless signal and the second wireless signal, and performing demodulation based on a signal obtained by the diversity synthesis, and a second wireless communication device that acquires the first application data based on the result of the first process.

Advantages of the Invention

[0008] According to the present disclosure, the second wireless communication device includes a receiver that performs a first process including performing diversity synthesis based on a first wireless signal and a second wireless signal having different frequencies, and performing demodulation based on a signal obtained by the diversity synthesis, and acquires first application data based on the result of the first process. With such a configuration, the wireless transmission quality can be improved as much as possible.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] <Embodiment 1> Before explaining the wireless communication system according to the present Embodiment 1, a system related to the wireless communication system (hereinafter referred to as "related system") will be explained.

[0011] FIG. 1 is a block diagram showing the configuration of the related system. The related system includes a terrestrial station 1 which is a first wireless communication device and a mobile body 2 which is a second wireless communication device, and the terrestrial station 1 and the mobile body 2 are configured to be able to transmit and receive wireless signals to and from each other. The related system is a system that redundantly transmits application data from the terrestrial station 1 to the mobile body 2 by using a first wireless signal and a second wireless signal having different frequencies from each other, that is, two wireless waves.

[0012] The terrestrial station 1 includes a first terrestrial application terminal 1a, a wireless format multiplexing unit 1b, a transmitter (f1) 1c, a transmitter (f2) 1d, and a synthesizer 1e, and is connected to a terrestrial station antenna 1f. The terrestrial station 1 configured in this way redundantly transmits application data by using a first wireless signal having a frequency f1 and a second wireless signal having a frequency f2 as described later.

[0013] The mobile body 2 is connected to the mobile body antenna 2a and includes a distributor 2b, a receiver (f1) 2c, a receiver (f2) 2d, a radio format separation unit 2e, and a first mobile body application terminal 2f. The mobile body 2 configured in this way acquires application data based on a first radio signal and a second radio signal, as will be described later.

[0014] Hereinafter, a mechanism for redundantly transmitting first data, which is first application data, from the first terrestrial application terminal 1a to the first mobile body application terminal 2f will be described in detail.

[0015] The first terrestrial application terminal 1a of the terrestrial station 1 branches the first data, which is the first application data, into two and outputs the same two pieces of first data to the radio format multiplexing unit 1b. The radio format multiplexing unit 1b inserts one of the same two pieces of first data into a predetermined location in the radio frame for frequency f1 and outputs it to the transmitter (f1) 1c. Further, the radio format multiplexing unit 1b inserts the other of the same two pieces of first data into a predetermined location in the radio frame for frequency f2 and outputs it to the transmitter (f2) 1d.

[0016] The transmitter (f1) 1c modulates the radio frame into which the first data is inserted into a first radio signal of frequency f1 and outputs it, and the transmitter (f2) 1d modulates the radio frame into which the first data is inserted into a second radio signal of frequency f2 and outputs it. The synthesizer 1e synthesizes the first radio signal and the second radio signal to generate a synthesized radio signal, and the terrestrial station antenna 1f outputs the synthesized radio signal into space.

[0017] The mobile antenna 2a of the mobile body 2 receives the combined radio signal from the ground station antenna 1f, and the distributor 2b branches the combined radio signal into two and supplies the same two combined radio signals to the receiver (f1) 2c and the receiver (f2) 2d respectively. The receiver (f1) 2c outputs the demodulation result such as a radio frame for frequency f1, which is obtained by demodulating the first radio signal of frequency f1 from the combined radio signal, to the radio format separation unit 2e. The receiver (f2) 2d outputs the demodulation result such as a radio frame for frequency f2, which is obtained by demodulating the radio signal of frequency f2 from the combined radio signal, to the radio format separation unit 2e.

[0018] Figure 2 is a block diagram showing the configuration of the receiver (f1) 2c of the related system. The receiver (f1) 2c includes a receiving circuit 2c2, an A / D converter 2c3, a BB converter (f1) 2c4, and a demodulator (f1) 2c6.

[0019] The receiving circuit 2c2 is connected to the output of the distributor 2b in FIG. 1, and the combined radio signal from the distributor 2b is input. The receiving circuit 2c2 amplifies the combined radio signal and converts it to an intermediate frequency IF of the radio frequency of the combined radio signal. The A / D converter 2c3 generates a digital signal of the intermediate frequency IF by performing A / D conversion on the signal obtained by the receiving circuit 2c2.

[0020] The BB converter (f1) 2c4 performs a conversion to band-limit the digital signal of the intermediate frequency IF generated by the A / D converter 2c3 to a baseband signal having only a component corresponding to the first radio signal of frequency f1. The demodulator (f1) 2c6 demodulates the baseband signal obtained by the BB converter (f1) 2c4 into a 0 / 1 signal and outputs a radio frame for frequency f1 or the like.

[0021] In this way, the receiver (f1) 2c demodulates the first radio signal of frequency f1 from the substantially combined radio signal, and outputs a demodulation result such as a radio frame for frequency f1. Note that the configuration of the receiver (f2) 2d is the same as that of the receiver (f1) 2c, except that the frequency f1 and the first radio signal are replaced with the frequency f2 and the second radio signal, respectively. Therefore, the receiver (f2) 2d demodulates the second radio signal of frequency f2 from the substantially combined radio signal, and outputs a demodulation result such as a radio frame for frequency f2.

[0022] The radio format separation unit 2e in FIG. 1 separates the first data from each of the radio frame for frequency f1 and the radio frame for frequency f2, and outputs the two pieces of first data to the first mobile application terminal 2f.

[0023] Note that depending on the radio link state, each of the two data output by the radio format separation unit 2e may not be the same as the first data processed by the terrestrial station 1. However, for convenience in the following description, each of the two data output by the radio format separation unit 2e will be described as the first data regardless of whether it is the same as the first data processed by the terrestrial station 1.

[0024] The first mobile application terminal 2f performs error detection using an error detection code such as CRC (Cyclic Redundancy Check) included in the first data. Then, the first mobile application terminal 2f adopts the error-free one of the two pieces of first data as the actually used data. In this way, the mobile body 2 of the related system performs frequency diversity for selecting the error-free one of the two pieces of first data after demodulating the first radio signal of frequency f1 and the second radio signal of frequency f2.

[0025] FIG. 3 is a diagram for explaining the frequency diversity of the related system. The first data 1A, 1B, 1C in FIG. 3 are redundantly transmitted by the first radio signal of frequency f1 and the second radio signal of frequency f2. For example, in FIG. 3, the first data 1B transmitted by the second radio signal of frequency f2 is determined to be an error by error detection, while the first data 1B transmitted by the first radio signal of frequency f1 is determined to be normal by error detection.

[0026] According to such a related system, even if the first data transmitted by one of the first radio signal and the second radio signal is an error, the mobile body 2 can acquire the normal first data transmitted by the other. As a result, the related system can realize redundancy in case of equipment failure and redundancy in radio transmission quality.

[0027] However, for example, when the signal levels of both the first radio signal and the second radio signal are partially reduced, as in the transmission of the first data 1C in FIG. 3, it may be determined that both the first data 1C transmitted by the first radio signal and the second radio signal are errors. In this case, the mobile body 2 cannot acquire the normal first data, and there is a problem that the radio transmission quality deteriorates. On the other hand, in the wireless communication system according to the first embodiment described below, it is possible to improve the radio transmission quality.

[0028] FIG. 4 is a block diagram showing the configuration of the wireless communication system according to the first embodiment. Hereinafter, among the components according to the first embodiment, the same or similar reference numerals are given to the components that are the same as or similar to the above-described components, and different components will be mainly described.

[0029] The configuration of the ground station 1 in FIG. 4 is the same as the configuration of the ground station 1 in FIG. 1. On the other hand, the configuration of the mobile body 2 in FIG. 4 is the same as the configuration of the mobile body 2 in FIG. 1, except that the receiver (f1) 2c and the receiver (f2) 2d are replaced with the receiver (f1 + f2) 2g and the receiver (f1 + f2) 2h, respectively.

[0030] FIG. 5 is a block diagram showing the configuration of the receiver (f1 + f2)2g according to Embodiment 1. The configuration of the receiver (f1 + f2)2g in FIG. 5 is the same as the configuration of the receiver (f1)2c in FIG. 2, except that the BB converter (f2)2g5 is added and the demodulator (f1)2c6 is replaced with the combined demodulator (f1 + f2)2g6.

[0031] The BB converter (f1)2g4 performs a conversion to band-limit the digital signal of the intermediate frequency IF generated by the A / D converter 2g3 into a baseband signal having only the component corresponding to the first radio signal of frequency f1. The BB converter (f2)2g5 performs a conversion to band-limit the digital signal of the intermediate frequency IF generated by the A / D converter 2g3 into a baseband signal having only the component corresponding to the second radio signal of frequency f2.

[0032] The combined demodulator (f1 + f2)2g6 generates a baseband signal to be demodulated by performing diversity synthesis based on the baseband signal obtained by the BB converter (f1)2g4 and the baseband signal obtained by the BB converter (f2)2g5. For example, the combined demodulator (f1 + f2)2g6 may generate a baseband signal to be demodulated by performing, as diversity synthesis, a process of sequentially selecting the larger signal level among the signal levels of the two baseband signals. Also, for example, the combined demodulator (f1 + f2)2g6 may perform various diversity syntheses such as frequency synthesis and weighted synthesis of the two baseband signals. The combined demodulator (f1 + f2)2g6 demodulates the baseband signal generated by diversity synthesis into a 0 / 1 signal and outputs a radio frame or the like.

[0033] As described above, the receiver (f1 + f2)2g performs a first process including performing diversity synthesis based on the first radio signal and the second radio signal, and performing demodulation based on the signal obtained by diversity synthesis. Note that the configuration of the receiver (f1 + f2)2h is the same as the configuration of the receiver (f1 + f2)2g.

[0034] The wireless format separation unit 2e separates first data from each of the wireless frames of the receivers (f1 + f2) 2g, 2h, and outputs the two pieces of first data to the first mobile application terminal 2f. The first mobile application terminal 2f adopts the error-free one of the two pieces of first data as the data to be actually used.

[0035] In this way, the mobile body 2 acquires the first data based on the wireless frames that are the results of the first processing of the receivers (f1 + f2) 2g, 2h.

[0036] <Summary of Embodiment 1> According to the wireless communication system according to the first embodiment as described above, the ground station 1 redundantly transmits the first data using the first wireless signal and the second wireless signal having different frequencies. The mobile body 2 includes receivers (f1 + f2) 2g, 2h that perform a first process including performing diversity synthesis based on the first wireless signal and the second wireless signal, and performing demodulation based on the signal obtained by the diversity synthesis. Then, the mobile body 2 acquires the first data based on the result of the first process.

[0037] According to such a configuration, for example, even when the wireless line state deteriorates and the signal levels of the baseband signals of the first wireless signal and the second wireless signal are partially reduced, the diversity synthesis gain can be increased by complementing the signal levels with each other. Therefore, normal first data can be acquired as much as possible, and thus the wireless transmission quality can be improved as much as possible. Also, without increasing the number of receiving antennas, that is, without significantly increasing the equipment cost and the antenna installation space, the wireless transmission quality can be improved as much as possible.

[0038] <Modification> In the first embodiment, the number of mobile antennas 2a connected to the mobile body 2 is one, but it may be two or more.

[0039] Also, in Embodiment 1, in order to achieve redundancy in the event of equipment failure and redundancy in radio transmission quality, the mobile body 2 included both receivers (f1 + f2) 2g and 2h. However, if only redundancy in radio transmission quality is to be achieved, the mobile body 2 may include only one of the receivers (f1 + f2) 2g and 2h and not the other.

[0040] Also, in Embodiment 1, the first wireless communication device was the ground station 1 and the second wireless communication device was the mobile body 2, but the first wireless communication device may be the mobile body 2 and the second wireless communication device may be the ground station 1. That is, the mobile body 2 redundantly transmits the first data using the first radio signal and the second radio signal, and the ground station 1 includes a receiver that performs diversity combining and demodulation in this order as the first process based on the first radio signal and the second radio signal, and may acquire the first data based on the result of the first process.

[0041] Note that the content of this modification example is also applicable to Embodiments 2 and later.

[0042] <Embodiment 2> The diversity combining gain increases as the correlation between the baseband signals used for diversity combining, and thus the correlation between the first radio signal and the second radio signal, becomes smaller. The first radio signal at frequency f1 and the second radio signal at frequency f2 pass through the same path from the ground station antenna 1f to the mobile body antenna 2a, but if the frequencies f1 and f2 are far apart, their correlation becomes smaller and the diversity combining gain becomes higher. However, from the perspective of radio frequency resource allocation in a wireless communication system, it is highly conceivable that the frequencies f1 and f2 will be close to each other in actual operation.

[0043] FIG. 6 is a diagram showing an example of a baseband signal output from the BB converter (f1) 2g4, a baseband signal output from the BB converter (f2) 2g5, and their diversity synthesis when the frequencies f1 and f2 are close to each other in Embodiment 1. Note that the baseband signal output from the BB converter (f1) 2g4 or the like is a digital signal, but in FIG. 6, for the sake of convenience, a signal having a smooth waveform is shown.

[0044] As shown in FIG. 6, when the frequencies f1 and f2 are close to each other, the correlation between the baseband signals indicating the same first application data becomes large, and there is a possibility that the diversity synthesis gain is not high. In Embodiment 2 described below, it is possible to solve such a problem.

[0045] FIG. 7 is a block diagram showing the configuration of the wireless communication system according to Embodiment 2. Hereinafter, among the components according to Embodiment 2, the same or similar components as the above-described components are given the same or similar reference numerals, and different components will be mainly described.

[0046] The configuration of the base station 1 in FIG. 7 is the same as the configuration of the base station 1 in FIG. 4, in which a delay element 1g is added between the radio format multiplexer 1b and the transmitter (f2) 1d. The base station 1 configured as shown in FIG. 7 delays the transmission process of the second radio signal by the delay element 1g.

[0047] The configuration of the mobile body 2 in FIG. 7 is the same as the configuration of the mobile body 2 in FIG. 4, in which the receivers (f1 + f2) 2g and (f1 + f2) 2h are replaced with the receivers (f1 + f2D) 2i and (f1 + f2D) 2j, respectively.

[0048] FIG. 8 is a block diagram showing the configuration of the receiver (f1 + f2D) 2i according to Embodiment 2. The configuration of the receiver (f1 + f2D) 2i in FIG. 8 is the same as the configuration of the receiver (f1 + f2) 2g in FIG. 5, except that a delay element 2i7 is added between the BB converter (f1) 2g4 and the combined demodulator (f1 + f2) 2g6. The mobile body 2 including the receiver (f1 + f2D) 2i configured as shown in FIG. 8 delays the reception process of the first radio signal used for diversity synthesis by the delay element 2i7. Note that the configuration of the receiver (f1 + f2D) 2j is the same as the configuration of the receiver (f1 + f2D) 2i.

[0049] In the entire wireless communication system according to Embodiment 2 configured as described above, the terrestrial station 1 delays the transmission data of the second radio signal with frequency f2, and the mobile body 2 delays the reception data of the first radio signal with frequency f1 used for diversity synthesis. Next, the operation of the wireless communication system according to Embodiment 2 will be described in detail.

[0050] FIG. 9 is a diagram for explaining the operation of the wireless communication system according to Embodiment 2. The delay element 1g of the terrestrial station 1 delays the transmission process of the second radio signal by delaying the signal before modulation for the second radio signal. As a result, the second radio signal is delayed by D with respect to the first radio signal and transmitted from the antenna 1f. When the frequencies f1 and f2 are close to each other, the correlation between the first radio signal with frequency f1 received by the mobile antenna 2a and the second radio signal with frequency f2 received by the mobile antenna 2a increases.

[0051] Here, in order to perform diversity synthesis based on the first radio signal with frequency f1 and the second radio signal with frequency f2, the data of the first radio signal with frequency f1 and the data of the second radio signal with frequency f2 need to be the same in the same period. In the example of FIG. 9, since the portion (hatched portion) corresponding to the range of the data of the second radio signal is shifted from the portion (hatched portion) corresponding to the range of the data of the first radio signal by the delay element 1g of the terrestrial station 1, it is necessary to align this portion.

[0052] To achieve this, the delay element 2i7 of the mobile body 2 delays the reception processing of the first radio signal by delaying the signal before demodulation of the first radio signal. As a result, the waveform of the baseband signal of the first radio signal is shifted by D in the time direction, and the data of the first radio signal with frequency f1 and the data of the second radio signal with frequency f2 become identical in the same period. Also, as shown in the diversity combining of FIG. 9, the correlation between the baseband signal output from the BB converter (f1) 2i4 and the baseband signal output from the BB converter (f2) 2i5 becomes small, so the diversity combining gain increases.

[0053] <Summary of Embodiment 2> According to the wireless communication system according to Embodiment 2 as described above, since the ground station 1 delays the transmission processing of the second radio signal and the mobile body 2 delays the reception processing of the first radio signal used for diversity combining, the diversity combining gain can be increased. In the above, the transmission processing of the second radio signal is delayed at the ground station 1, and the reception processing of the first radio signal is delayed at the mobile body 2. However, even if the transmission processing of the first radio signal is delayed at the ground station 1 and the reception processing of the second radio signal is delayed at the mobile body 2, the diversity combining gain can be increased in the same manner as above.

[0054] <Embodiment 3> In Embodiment 1 and Embodiment 2, since only the first data is transmitted, there is a problem that radio resources are not effectively utilized. In Embodiment 3 described below, it is possible to solve such a problem.

[0055] FIG. 10 is a block diagram showing the configuration of a wireless communication system according to Embodiment 3. Hereinafter, among the components according to Embodiment 3, the same or similar components as the above-described components are given the same or similar reference numerals, and different components will be mainly described.

[0056] The configuration of the terrestrial station 1 in FIG. 10 is the same as the configuration of the terrestrial station 1 in FIG. 7, with the addition of the second terrestrial application terminal 1h and the third terrestrial application terminal 1i. The second terrestrial application terminal 1h outputs the second data, which is a type of second application data, to the wireless format multiplexing unit 1b. The third terrestrial application terminal 1i outputs the third data, which is a type of second application data, to the wireless format multiplexing unit 1b. Note that the second data and the third data may be the same or different.

[0057] The wireless format multiplexing unit 1b inserts one of the two identical first data and the second data into a predetermined location within the wireless frame for frequency f1 and outputs it to the transmitter (f1) 1c. Also, the wireless format multiplexing unit 1b inserts the other of the two identical first data and the third data into a predetermined location within the wireless frame for frequency f2 and outputs it to the transmitter (f2) 1d via the delay element 1g.

[0058] The transmitter (f1) 1c modulates the wireless frame into which the first data and the second data are inserted into a first wireless signal of frequency f1 and outputs it. The transmitter (f2) 1d modulates the wireless frame into which the first data and the third data are inserted into a second wireless signal of frequency f2 and outputs it. The synthesizer 1e synthesizes the first wireless signal and the second wireless signal to generate a synthesized wireless signal, and the terrestrial station antenna 1f outputs the synthesized wireless signal into space.

[0059] The terrestrial station 1 configured as shown in FIG. 10 uses the first wireless signal as a predetermined wireless signal to transmit not only the first data but also the second data, which is a type of second application data. Also, the terrestrial station 1 uses the second wireless signal as a predetermined wireless signal to transmit not only the first data but also the third data, which is a type of second application data.

[0060] The configuration of the mobile body 2 in FIG. 10 is the same as the configuration of the mobile body 2 in FIG. 7, except that the receivers (f1 + f2D) 2i and (f1 + f2D) 2j are replaced by the receivers (f1 / f1 + f2D) 2k and (f2 / f1 + f2D) 2l respectively, and the second mobile application terminal 2m and the third mobile application terminal 2n are added.

[0061] FIG. 11 is a block diagram showing the configuration of the receiver (f1 / f1 + f2D) 2k according to the third embodiment. The configuration of the receiver (f1 / f1 + f2D) 2k in FIG. 11 is the same as the configuration of the receiver (f1 + f2D) 2i in FIG. 8, except that the demodulator (f1) 2k8 is added. The demodulator (f1) 2k8 demodulates the baseband signal of the first radio signal into a 0 / 1 signal without performing diversity combining, and outputs a radio frame for frequency f1 and the like. The receiver (f1 / f1 + f2D) 2k configured in this way performs not only the first process described in the first embodiment, but also a second process including demodulating without performing diversity combining based on the first radio signal.

[0062] Note that the configuration of the receiver (f2 / f1 + f2D) 2l is the same as the configuration of the receiver (f1 / f1 + f2D) 2k, except that a demodulator (f2) is provided instead of the demodulator (f1) 2k8. The receiver (f2 / f1 + f2D) 2l configured in this way performs not only the first process described in the first embodiment, but also a second process including demodulating without performing diversity combining based on the second radio signal.

[0063] FIG. 12 is a diagram for explaining the operation of the wireless format separation unit 2e. The wireless format separation unit 2e separates the first data 1A, 1B, 1C based on the signal demodulation result with diversity combining of the receiver (f1 / f1 + f2D) 2k and the signal demodulation result with diversity combining of the receiver (f2 / f1 + f2D) 2l, and outputs the separated data to the first mobile application terminal 2f. Note that the wireless format separation unit 2e may separate the first data 1A, 1B, 1C based on the signal demodulation result without diversity combining of the receiver (f1 / f1 + f2D) 2k or the signal demodulation result without diversity combining of the receiver (f2 / f1 + f2D) 2l, and output the separated data to the first mobile application terminal 2f. The wireless format separation unit 2e separates the second data 2A, 2B, 2C based on the signal demodulation result without diversity combining of the receiver (f1 / f1 + f2D) 2k, and outputs the separated data to the second mobile application terminal 2m. Further, the wireless format separation unit 2e separates the third data 3A, 3B, 3C based on the signal demodulation result without diversity combining of the receiver (f2 / f1 + f2D) 2l, and outputs the separated data to the third mobile application terminal 2n.

[0064] The mobile body 2 configured as described above acquires the first data based on the wireless frame which is the result of the first process of the receiver (f1 / f1 + f2D) 2k and the receiver (f2 / f1 + f2D) 2l. Further, the mobile body 2 acquires the second data and the third data based on the wireless frame which is the result of the second process of the receiver (f1 / f1 + f2D) 2k and the receiver (f2 / f1 + f2D) 2l. In the above description, the number of ground application terminals and the number of types of application data are three, but two or more are sufficient.

[0065] <Summary of Embodiment 3> According to the wireless communication system according to Embodiment 3 as described above, the terrestrial station 1 further transmits the second data using the first radio signal and further transmits the third data using the second radio signal. Then, the receiver (f1 / f1 + f2D) 2k performs a second process including demodulating without performing diversity combining based on the first radio signal, and the mobile body 2 acquires the second data based on the result of the second process. Similarly, the receiver (f2 / f1 + f2D) 2l performs a second process including demodulating without performing diversity combining based on the second radio signal, and the mobile body 2 acquires the third data based on the result of the second process.

[0066] According to such a configuration, since the wireless communication system transmits not only the first data but also the second data or the third data, the wireless resources can be effectively utilized. In addition, transmission can be changed according to the nature of the application, for example, one application performs redundant transmission using both the first radio signal and the second radio signal, while another application performs transmission using only the first radio signal or the second radio signal.

[0067] It should be noted that each embodiment and each modification can be freely combined, or each embodiment and each modification can be appropriately modified or omitted.

[0068] Hereinafter, various aspects of the present disclosure will be summarized and described as appendices.

[0069] (Appendix 1) A first wireless communication device that redundantly transmits first application data using a first radio signal and a second radio signal having different frequencies from each other, A receiver that performs a first process including performing diversity combining based on the first radio signal and the second radio signal and demodulating based on the signal obtained by the diversity combining, and a second wireless communication device that acquires the first application data based on the result of the first process A wireless communication system comprising:

[0070] (Appendix 2) The wireless communication system according to Supplementary Note 1, wherein the first wireless communication device delays the transmission process of one of the first wireless signal and the second wireless signal, and the second wireless communication device delays the reception process of the other of the first wireless signal and the second wireless signal used for the diversity synthesis, a wireless communication system.

[0071] (Supplementary Note 3) The wireless communication system according to Supplementary Note 1 or Supplementary Note 2, wherein the first wireless communication device further transmits second application data by using the first wireless signal or the second wireless signal as a predetermined wireless signal, the receiver performs a second process including demodulating without performing diversity synthesis based on the predetermined wireless signal, and the second wireless communication device acquires the second application data based on the result of the second process, a wireless communication system.

Explanation of Reference Numerals

[0072] 1 Base station, 2 Mobile body, 2g, 2h Receiver (f1 + f2), 2i, 2j Receiver (f1 + f2D), 2k Receiver (f1 / f1 + f2D), 2l Receiver (f2 / f1 + f2D).

Claims

1. A first wireless communication device that redundantly transmits first application data using a first wireless signal and a second wireless signal having different frequencies, and a receiver that performs a first process including performing diversity combining based on the first wireless signal and the second wireless signal, and performing demodulation based on the signal obtained by the diversity combining, and the second wireless communication device that acquires the first application data based on the result of the first process A wireless communication system comprising:

2. The wireless communication system according to claim 1, wherein the first wireless communication device delays transmission processing of one of the first wireless signal and the second wireless signal, the second wireless communication device delays reception processing of the other of the first wireless signal and the second wireless signal used for the diversity combining. The wireless communication system.

3. The wireless communication system according to claim 1 or claim 2, wherein the first wireless communication device further transmits second application data using the first wireless signal or the second wireless signal as a predetermined wireless signal, the receiver performs a second process including performing demodulation without performing diversity combining based on the predetermined wireless signal, the second wireless communication device acquires the second application data based on the result of the second process. The wireless communication system.

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