Wireless communication device and wireless communication system

Abstract

This wireless communication device (100) includes an antenna element (110), a passive element which rotates around the antenna element (110), a wireless transmission unit (140) for transmitting a signal from the antenna element (110), and a processor (120) connected to the wireless transmission unit (140). The processor (120) determines a sample timing for use in transmission of the signal on the basis of a channel state, causes control data serving as notification of the determined sample timing to be transmitted from the wireless transmission unit (140), executes weighting processing of a plurality of data series using a weighting factor corresponding to the channel state of the determined sample timing, and executes processing for causing the plurality of data series subjected to weighting processing to be transmitted from the wireless transmission unit (140).

Description

[Technical field]

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

[0002] In recent years, the fifth generation mobile communication (5G) has started practical operation, and the sixth generation mobile communication (6G) is under study. VM-MIMO (Virtual Massive-MIMO) is one of the candidate technologies to be adopted for 6G communication.

[0003] In VM-MIMO, parasitic elements are arranged around the antenna of the receiving wireless communication device, and periodic channel fluctuations are generated by rotating these parasitic elements at high speed, thereby performing MIMO receiving processing on received signals with different sample timings. That is, the receiving wireless communication device separates multiplexed data sequences contained in the received signal by MIMO receiving processing.

[0004] VM-MIMO does not require an increased number of antennas as in MIMO, so it is a technology that can suppress the increase in size of equipment while increasing transmission capacity. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-68174 A [Patent Document 2] JP 2019-197987 A [Patent Document 3] JP 2020-68494 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, there is a problem in that there are no examples of research into technology for increasing transmission capacity without increasing the number of antennas in a transmitting wireless communication device.

[0007] That is, in normal MIMO, the transmission capacity is increased by providing multiple antennas to both the transmitting and receiving wireless communication devices, and the increase in the number of antennas results in an increase in the size of the wireless communication devices. In contrast, in VM-MIMO, the transmission capacity is increased without increasing the number of antennas in the receiving wireless communication device. However, even in VM-MIMO, the transmitting wireless communication device still has multiple antennas and transmits a data sequence from each antenna, resulting in an increase in the size of the transmitting wireless communication device.

[0008] The disclosed technology has been made in consideration of the above points, and aims to provide a wireless communication device and a wireless communication system that can increase transmission capacity while suppressing an increase in the size of the device. [Means for solving the problem]

[0009] In one aspect, a wireless communication device disclosed in the present application has an antenna element, a parasitic element rotating around the antenna element, a wireless transmission unit that transmits a signal from the antenna element, and a processor connected to the wireless transmission unit, wherein the processor determines a sample timing to be used for transmitting the signal based on a channel state, causes the wireless transmission unit to transmit control data notifying the determined sample timing, performs weighting processing on a plurality of data series using a weighting coefficient corresponding to the channel state of the determined sample timing, and performs processing to transmit the weighted plurality of data series from the wireless transmission unit. Effect of the Invention

[0010] According to one aspect of the wireless communication device and wireless communication system disclosed in the present application, it is possible to increase the transmission capacity while suppressing an increase in the size of the device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a configuration of a wireless transmission device according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a configuration of a wireless receiving device according to an embodiment. [Diagram 3] FIG. 3 is a sequence diagram showing a wireless communication method according to an embodiment. [Figure 4] FIG. 4 is a diagram showing a specific example of a received signal. [Diagram 5] FIG. 5 is a sequence diagram showing a wireless communication method according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a wireless communication device and a wireless communication system disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment.

[0013] 1 is a block diagram showing a configuration of a radio transmission device 100 according to an embodiment. The radio transmission device 100 shown in FIG.

[0014] The antenna element 110 is a power supply element connected to the wireless communication unit 140, and transmits and receives wireless signals.

[0015] Parasitic element 115 is a rod-shaped metallic element attached to antenna element 110, and rotates at a predetermined period around antenna element 110. As parasitic element 115 rotates around antenna element 110, the propagation path of the radio signal transmitted from antenna element 110 fluctuates at a predetermined period.

[0016] The processor 120 includes, for example, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or a DSP (Digital Signal Processor), and generally controls the entire radio transmitting device 100. Specifically, the processor 120 includes a reference signal acquisition unit 121, a channel state measurement unit 122, a sample timing determination unit 123, a weight determination unit 124, a control data generation unit 125, an information data generation unit 126, a multiplexing unit 127, a weighting processing unit 128, and a synthesis unit 129.

[0017] The reference signal acquisition unit 121 acquires a reference signal for channel estimation received by the wireless communication unit 140. The reference signal is a known signal transmitted from a wireless receiving apparatus with which the wireless transmitting apparatus 100 communicates.

[0018] The channel state measurement unit 122 measures the channel state by using the reference signal acquired by the reference signal acquisition unit 121. That is, the channel state measurement unit 122 measures the channel state of the line from the wireless receiving device to the wireless transmitting device 100 by channel estimation using the reference signal. Note that, since the wireless transmitting device 100 and the wireless receiving device perform wireless communication by Time Division Duplex (TDD), the line from the wireless receiving device to the wireless transmitting device 100 and the line from the wireless transmitting device 100 to the wireless receiving device are symmetrical, and the channel states of both lines are assumed to be substantially the same.

[0019] The sample timing determination unit 123 determines the sample timing to be used for wireless transmission of the signal based on the channel state. At this time, the sample timing determination unit 123 may determine, for example, the sample timing at which the channel state is better than a predetermined standard as the sample timing to be used for wireless transmission of the signal.

[0020] The weight determination unit 124 determines a weight coefficient for each of a plurality of data sequences to be transmitted simultaneously, the weight coefficient corresponding to the sample timing determined by the sample timing determination unit 123. The weight coefficient determined by the weight determination unit 124 is a weight coefficient for correcting the influence on the signal due to the channel state at the sample timing, and for example, a pseudo propagation path coefficient or a spreading sequence can be used as the weight coefficient.

[0021] The control data generator 125 generates control data for notifying the wireless receiving device of the sample timing determined by the sample timing determiner 123 .

[0022] The information data generating unit 126 generates information data including information to be transmitted. At this time, the information data generating unit 126 generates information data of a plurality of data series to be transmitted simultaneously. The plurality of data series may include the same information data or may include different information data.

[0023] The multiplexing unit 127 multiplexes the information data, the control data, and the reference signal, i.e., the multiplexing unit 127 maps the information data, the control data, and the reference signal to respective times and frequencies.

[0024] The weighting processing unit 128 weights each of the multiple data series of the information data using the weighting coefficients determined by the weight determination unit 124. Specifically, the weighting processing unit 128 includes a multiplier corresponding to each data series, and multiplies each data series by the weighting coefficient for that data series.

[0025] The combiner 129 combines a plurality of data series of information data. Then, the combiner 129 outputs a transmission signal obtained by combining the plurality of data series to the wireless communication unit 140. Furthermore, the combiner 129 outputs a transmission signal including control data and a transmission signal including a reference signal to the wireless communication unit 140.

[0026] The memory 130 includes, for example, a random access memory (RAM) or a read only memory (ROM), and stores information used in processing by the processor 120.

[0027] The wireless communication unit 140 performs predetermined wireless transmission processing such as D / A (Digital / Analog) conversion and up-conversion on the transmission signal output from the combiner 129, and transmits the signal wirelessly from the antenna element 110. The transmission signal wirelessly transmitted from the antenna element 110 is transmitted to the wireless receiving device through a propagation path according to the rotation of the parasitic element 115. The wireless communication unit 140 also performs predetermined wireless reception processing such as down-conversion and A / D (Analog / Digital) conversion on the reference signal received by the antenna element 110, and outputs the signal to the processor 120.

[0028] Fig. 2 is a block diagram showing a configuration of a wireless receiving device 200 according to an embodiment. The wireless receiving device 200 receives a transmission signal transmitted from the wireless transmitting device 100 shown in Fig. 1. The wireless receiving device 200 shown in Fig. 2 includes an antenna element 210, a wireless communication unit 220, a processor 230, and a memory 240.

[0029] The antenna element 210 is a power supply element connected to the wireless communication unit 220, and transmits and receives wireless signals.

[0030] The wireless communication unit 220 performs predetermined wireless reception processing such as down-conversion and A / D conversion on the signal received by the antenna element 210, and outputs the signal to the processor 230. The wireless communication unit 220 also wirelessly transmits a reference signal from the antenna element 110 to the wireless transmission device 100.

[0031] The processor 230 includes, for example, a CPU, an FPGA, or a DSP, and generally controls the entire wireless receiving device 200. Specifically, the processor 230 includes a reference signal acquisition unit 231, a channel state measurement unit 232, a reception control unit 234, a sample timing adjustment unit 235, a separation processing unit 236, and a demodulation and decoding unit 237.

[0032] The reference signal acquisition unit 231 acquires a reference signal for channel estimation from among the signals received by the wireless communication unit 220. The reference signal is a known signal transmitted from the wireless transmission device 100.

[0033] The channel state measurement unit 232 measures the channel state by using the reference signal acquired by the reference signal acquisition unit 231. That is, the channel state measurement unit 232 measures the channel state of the link from the radio transmitting device 100 to the radio receiving device 200 by channel estimation using the reference signal.

[0034] The reception control unit 234 acquires control data from the reception signal received by the wireless communication unit 220, and controls reception of information data based on the control data and the channel state. Specifically, the reception control unit 234 corrects the sample timing notified by the control data in accordance with the channel state, and notifies the obtained reception sample timing to the sample timing adjustment unit 235. The reception control unit 234 also determines a weighting coefficient in accordance with the channel state of the reception sample timing, and notifies the separation processing unit 236 of the determined weighting coefficient.

[0035] The sample timing adjustment section 235 obtains a signal of the reception sample timing from the signal received by the wireless communication section 220 in accordance with the reception sample timing notified by the reception control section 234 .

[0036] The separation processing unit 236 weights the signal at the reception sample timing by the weighting coefficient notified by the reception control unit 234 , and separates the multiple data series combined in the radio transmitting apparatus 100 .

[0037] The demodulation / decoding unit 237 demodulates and decodes each of the multiple data series to obtain information data. The multiple data series include the same information data or different information data.

[0038] The memory 240 includes, for example, a RAM or a ROM, and stores information used in processing by the processor 230.

[0039] Next, a wireless communication method performed by wireless transmitting device 100 and wireless receiving device 200 configured as above will be described with reference to a sequence diagram shown in FIG.

[0040] When the wireless transmission device 100 and the wireless reception device 200 perform wireless communication, a time synchronization process is performed between these devices (step S101). The time synchronization process can be performed using, for example, PTP (Precision Time Protocol) or GPS (Global Positioning System). By synchronizing the time between the wireless transmission device 100 and the wireless reception device 200, it becomes possible to transmit and receive signals between the two devices.

[0041] Therefore, the wireless receiving device 200 transmits a reference signal for channel measurement (step S102). The wireless receiving device 200 may transmit the reference signal periodically. The reference signal is received by the wireless communication unit 140 of the wireless transmitting device 100 and acquired by the reference signal acquisition unit 121. Then, the channel state measurement unit 122 uses the reference signal to measure the channel state of the line from the wireless receiving device 200 to the wireless transmitting device 100 (step S103). The channel state is notified to the sample timing determination unit 123, and a sample timing based on the channel state is determined (step S104). That is, for example, a sample timing at which the channel state is better than a predetermined standard is determined to be the sample timing to be used for wireless transmission of a signal.

[0042] When the sample timing is determined, the weight determining unit 124 determines a weighting coefficient for each of the multiple data sequences to be simultaneously transmitted in accordance with the sample timing (step S105). The determined weighting coefficients are set in the weighting processing unit 128. Furthermore, the control data generating unit 125 generates control data for notifying the sample timing, and transmits the control data from the wireless communication unit 140 to the wireless receiving device 200 (step S106). Furthermore, the wireless transmitting device 100 transmits a reference signal for channel measurement (step S107). The transmission of the reference signal by the wireless transmitting device 100 may be performed periodically.

[0043] The control data and the reference signal are received by the wireless communication unit 220 of the wireless receiving device 200, and the channel state measurement unit 232 uses the reference signal to measure the channel state of the line from the wireless transmitting device 100 to the wireless receiving device 200 (step S108). Then, the reception control unit 234 corrects the sample timing notified by the control data based on the channel state, and determines the reception sample timing. The determined reception sample timing is set in the sample timing adjustment unit 235 (step S109).

[0044] Meanwhile, in the wireless transmission device 100, information data of a plurality of data series is generated, and the weighting processing unit 128 performs weighting processing on each data series (step S110). At this time, since the channel state varies due to the rotation of the parasitic element 115, the weighting processing may be performed with a different weighting coefficient for each sample timing according to the rotation period of the parasitic element 115. The weighted information data of the plurality of data series is combined by the combining unit 129, and then wirelessly transmitted from the antenna element 110 (step S111).

[0045] Since the parasitic element 115 rotates around the antenna element 110, the signal transmitted from the antenna element 110 is transmitted through a channel that changes at each sample timing. Specifically, as shown in FIG. 4(a), for example, the I and Q components of the signal change periodically according to the rotation period of the parasitic element 115. If this signal is shown on an IQ plane, as shown in FIG. 4(b), for example, the signal point rotates in accordance with the rotation period of the parasitic element 115. In this way, the signal transmitted through the channel that changes at each sample timing is received by the antenna element 210 of the wireless receiving device 200.

[0046] The received signal is then input to the sample timing adjustment unit 235, in which the reception sample timing is set, and a signal of the reception sample timing is acquired from the received signal. The signal of the reception sample timing is weighted by the separation processing unit 236 and separated into information data of a plurality of data series (step S112). Then, the information data of each data series is demodulated and decoded by the demodulation and decoding unit 237.

[0047] As described above, according to this embodiment, a parasitic element that rotates around the antenna element of a wireless transmitting device is provided, and the wireless transmitting device notifies the wireless receiving device of a sample timing determined according to a channel state, and transmits multiple data series with weighting. Therefore, the wireless receiving device can extract a signal corresponding to the notified sample timing from a received signal received via a channel that varies according to the rotation period of the parasitic element, and separate the multiple data series. As a result, it is possible to increase the transmission capacity while suppressing an increase in the size of the device.

[0048] In the above embodiment, since the radio transmitting device 100 and the radio receiving device 200 perform radio communication by TDD, it is assumed that the channel state of the line from the radio receiving device 200 to the radio transmitting device 100 and the line from the radio transmitting device 100 to the radio receiving device 200 are almost the same. However, even when the radio transmitting device 100 and the radio receiving device 200 perform radio communication by Frequency Division Duplex (FDD), it is possible to implement a radio communication method similar to that of the above embodiment. However, when radio communication by FDD is performed, the channel state measured by the radio receiving device 200 is reported to the radio transmitting device 100, and the radio transmitting device 100 determines the sample timing based on this report.

[0049] Fig. 5 is a sequence diagram showing a wireless communication method when wireless communication according to FDD is performed. In Fig. 5, the same parts as in Fig. 3 are given the same reference numerals, and detailed description thereof will be omitted.

[0050] When the wireless transmission device 100 and the wireless reception device 200 perform wireless communication, a time synchronization process is performed between these devices (step S101). Then, the wireless transmission device 100 transmits a reference signal for channel measurement (step S201). The wireless transmission device 100 may transmit the reference signal periodically. The reference signal is received by the wireless communication unit 220 of the wireless reception device 200 and acquired by the reference signal acquisition unit 231. Then, the channel state measurement unit 232 uses the reference signal to measure the channel state of the line from the wireless transmission device 100 to the wireless reception device 200 (step S202). The measured channel state is reported to the wireless transmission device 100 by report information (step S203). That is, the wireless reception device 200 generates report information for reporting the channel state of the line from the wireless transmission device 100 to the wireless reception device 200, and transmits the report information to the wireless transmission device 100.

[0051] The channel state reported from wireless receiving device 200 is notified to sample timing determination section 123 of wireless transmitting device 100, and a sample timing based on the channel state is determined (step S104). The sample timing determined here is based on the channel state of the line from wireless transmitting device 100 to wireless receiving device 200, and it is possible to determine a sample timing according to the line of the frequency through which a signal is actually transmitted.

[0052] When the sample timing is determined, the weight determination unit 124 determines a weighting coefficient for each of the multiple data series to be simultaneously transmitted in accordance with the sample timing (step S105). The determined weighting coefficients are set in the weighting processing unit 128. Furthermore, control data for notifying the sample timing is generated by the control data generation unit 125 and transmitted from the wireless communication unit 140 to the wireless receiving device 200 (step S106). The control data is received by the wireless communication unit 220 of the wireless receiving device 200, and the sample timing notified by the control data is set by the reception control unit 234 in the sample timing adjustment unit 235 as the reception sample timing (step S109).

[0053] Meanwhile, in the radio transmitting device 100, information data of a plurality of data series is generated, and the weighting processing unit 128 performs weighting processing on each data series (step S110). The weighted information data of the plurality of data series is combined by the combining unit 129, and then wirelessly transmitted from the antenna element 110 (step S111). The wirelessly transmitted signal is received by the radio receiving device 200, and the received signal is input to the sample timing adjustment unit 235 in which the reception sample timing is set. Then, a signal of the reception sample timing is obtained from the received signal, and this signal is weighted by the separation processing unit 236, thereby separating the signal into information data of a plurality of data series (step S112). The information data of each data series is demodulated and decoded by the demodulation and decoding unit 237.

[0054] In this way, even when FDD is adopted in which different frequencies are used for the line from the wireless transmitting device 100 to the wireless receiving device 200 and the line from the wireless receiving device 200 to the wireless transmitting device 100, it is possible to increase the transmission capacity while suppressing an increase in the size of the device. [Explanation of symbols]

[0055] 110, 210 Antenna element 115 Parasitic element 120, 230 processor 121, 231 Reference signal acquisition section 122, 232 Channel condition measurement unit 123 Sample timing determination unit 124 Weight determination unit 125 Control Data Generation Unit 126 Information Data Generation Unit 127 Multiplexer 128 Weighting Processing Unit 129 Synthesis Section 130, 240 Memory 140, 220 Wireless communication section 234 Reception control section 235 Sample timing adjustment section 236 Separation Processing Section 237 Demodulation and Decoding Section

Claims

1. An antenna element; a parasitic element that rotates around the antenna element; a wireless transmitting unit for transmitting a signal from the antenna element; a processor coupled to the wireless transmitter; The processor, determining a sample timing for transmitting the signal based on the channel conditions; causing the wireless transmission unit to transmit control data notifying the determined sample timing; performing weighting processing on the plurality of data sequences using weighting coefficients according to the channel state at the determined sample timing; The weighted data series are transmitted from the wireless transmission unit. A wireless communication device that performs processing.

2. The process of determining includes: measuring a channel condition using the received reference signal; The sample timing is determined based on the measured channel condition.

2. The wireless communication device according to claim 1.

3. The process of determining includes: Receive report information reporting a measurement result of a channel state; determining said sample timing based on reported channel conditions 2. The wireless communication device according to claim 1.

4. An antenna element; a wireless receiving unit that receives a signal by the antenna element; a processor coupled to the wireless receiver; The processor, obtaining control data indicating sample timing to be used in transmitting the signal; obtaining a signal corresponding to the notified sample timing from a received signal received by the wireless receiving unit; Separating a plurality of data sequences contained in the acquired signal using a weighting factor according to the channel state at the notified sample timing; Decoding multiple separated data series A wireless communication device that performs processing.

5. A wireless communication system having a first wireless communication device and a second wireless communication device, The first wireless communication device is A first antenna element; a parasitic element that rotates around the first antenna element; a wireless transmitting unit for transmitting a signal from the first antenna element; a first processor connected to the wireless transmitter; The first processor, determining a sample timing for transmitting the signal based on the channel conditions; causing the wireless transmission unit to transmit control data notifying the determined sample timing; performing weighting processing on the plurality of data sequences using weighting coefficients according to the channel state at the determined sample timing; Executing a process of transmitting the weighted data series from the wireless transmission unit; The second wireless communication device is A second antenna element; and a radio receiving unit that receives a signal by the second antenna element; a second processor connected to the wireless receiver; The second processor, Obtaining control data transmitted from the first wireless communication device; obtaining a signal corresponding to a sample timing notified by the control data from a received signal received by the wireless receiving unit; Separating a plurality of data sequences contained in the acquired signal using a weighting factor according to the channel state at the notified sample timing; Execute the process of decoding the separated multiple data series 1. A wireless communication system comprising:

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