Base station device, terminal device, wireless communication system, and wireless communication method

Abstract

A base station device (100) comprises: a processor (110) that generates a first pilot signal and a plurality of second pilot signals, multiplies the first pilot signal by a first antenna weight, and multiplies the plurality of second pilot signals by a second antenna weight; and a wireless transmission unit (130) that transmits the first pilot signal and the plurality of second pilot signals. A terminal device (200) comprises: a wireless reception unit (210) that receives the first pilot signal and the plurality of second pilot signals; a processor (230) that measures the received power of the first pilot signal and the plurality of second pilot signals and generates report information including the measurement result of the received power; and a wireless transmission unit (220) that transmits the report information generated by the processor (230) to the base station device (100).

Description

[Technical Field]

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

[0002] One of the wireless communication technologies currently being considered for the 6th generation mobile communication system is RIS (Reconfigurable Intelligent Surface) technology. RIS is a variable angle reflector constructed by arranging many RIS elements, consisting of variable capacitance diodes, etc., two-dimensionally on a dielectric substrate at intervals of less than half a wavelength. With RIS technology, it is possible to change the reflection angle of radio waves at the RIS by changing the voltage applied to the RIS elements.

[0003] By using such a RIS to change the propagation direction of a radio signal transmitted from a base station, it becomes possible to adjust the propagation direction of an ultra-high frequency band radio signal, which is suitable for large-capacity data transmission but has a strong tendency to travel in a straight line. Therefore, even if a terminal device is located in a position where it is difficult to receive a radio signal from a base station due to an obstacle, it will be able to receive the radio signal reflected by the RIS, thereby realizing large-capacity data transmission using an ultra-high frequency band radio signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2015-530018 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-153095 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when introducing RIS technology into a wireless communication system, there is still no research example on the method of determining whether it is better for the base station device and the terminal device to communicate directly without passing through RIS or to communicate through RIS. Furthermore, when the base station device and the terminal device communicate through RIS, no method for determining an appropriate reflection angle in RIS has been considered. Therefore, even if RIS technology is introduced into a wireless communication system, there is a problem that the propagation direction of the wireless signal is not appropriately adjusted and the wireless quality cannot necessarily be improved.

[0006] The disclosed technology has been made in view of such points, and an object thereof is to provide a base station device, a terminal device, a wireless communication system, and a wireless communication method capable of improving wireless quality.

Means for Solving the Problems

[0007] In one aspect, the base station device disclosed in the present application generates a first pilot signal and a plurality of second pilot signals, multiplies the first pilot signal by a first antenna weight, and multiplies the plurality of second pilot signals by a second antenna weight, and a wireless transmission unit that transmits the first pilot signal and the plurality of second pilot signals.

Effects of the Invention

[0008] According to one aspect of the base station device, the terminal device, the wireless communication system, and the wireless communication method disclosed in the present application, there is an effect that the wireless quality can be improved.

Brief Description of the Drawings

[0009]

Figure 1

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[0010] Hereinafter, an embodiment of a base station apparatus, a terminal apparatus, a wireless communication system, and a wireless communication method 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.

[0011] 1 is a diagram showing an example of the configuration of a wireless communication system according to an embodiment, which includes a base station device 100, terminal devices 200a and 200b, and a RIS 300.

[0012] The base station device 100 performs wireless communication with the terminal devices 200a and 200b. At this time, the base station device 100 determines whether to perform wireless communication with each of the terminal devices 200a and 200b via the RIS 300, and transmits wireless signals to the terminal devices 200a and 200b using a transmission method according to the result of the determination. In the example shown in FIG. 1, the base station device 100 transmits a wireless signal directly to the terminal device 200a, and transmits a wireless signal to the terminal device 200b via the RIS 300. That is, because there is an obstacle between the base station device 100 and the terminal device 200b, an ultra-high frequency band wireless signal, which has a strong tendency to travel in a straight line, is not propagated from the base station device 100 to the terminal device 200b, so the base station device 100 reflects the wireless signal at the RIS 300 and transmits it to the terminal device 200b.

[0013] The base station device 100 determines the transmission method for the terminal devices 200a and 200b by transmitting a normal pilot signal and a pilot signal for determining the transmission method. That is, the base station device 100 transmits, as a pilot signal for determining the transmission method, a pilot signal that is different for each reflection angle in the RIS 300. Then, the base station device 100 receives reports of the received power of the normal pilot signal and the pilot signal for each reflection angle in the RIS 300 at the terminal devices 200a and 200b, and determines whether to transmit a radio signal to the terminal devices 200a and 200b via the RIS 300. Further, when transmitting a radio signal via the RIS 300, the base station device 100 determines the optimal reflection angle in the RIS 300 from the received power of the pilot signal for each reflection angle.

[0014] The terminal devices 200a and 200b perform wireless communication directly with the base station device 100 or via the RIS 300. The terminal devices 200a and 200b receive the pilot signal transmitted from the base station device 100 and measure the received power. At this time, the terminal devices 200a and 200b receive a pilot signal that is different for each reflection angle in the RIS 300 and measure the received power of the pilot signal for each reflection angle. Then, the terminal devices 200a and 200b identify the pilot signal with the maximum received power and report information regarding the maximum received power to the base station device 100.

[0015] The RIS 300 is a variable-angle reflector in which a plurality of RIS elements are two-dimensionally arranged on a dielectric substrate. The RIS 300 receives a radio signal transmitted from the base station device 100 and changes the reflection angle of the radio signal by controlling the voltage applied to the RIS element according to the received signal. That is, the RIS 300 changes the reflection angle of the radio signal according to the control from the base station device 100 and reflects a pilot signal that is different for each reflection angle at the corresponding reflection angle.

[0016] FIG. 2 is a block diagram showing the configuration of the RIS 300. The RIS 300 shown in FIG. 2 includes a wireless reception unit 310, a signal processing unit 320, an applied voltage control unit 330, and a RIS element group 340.

[0017] The wireless reception unit 310 receives a wireless signal transmitted from the base station device 100. Specifically, the wireless reception unit 310 receives a control signal for controlling the reflection angle of the wireless signal in the RIS 300. As this control signal, for example, pilot signals of different patterns corresponding to the magnitude of the reflection angle can be used. That is, the wireless reception unit 310 receives pilot signals different for each reflection angle from the base station device 100.

[0018] The signal processing unit 320 acquires a control signal for controlling the reflection angle from the received signal in the wireless reception unit 310. Specifically, the signal processing unit 320 detects a pilot signal from the base station device 100 and specifies the control content of the reflection angle corresponding to the pilot signal. Then, the signal processing unit 320 notifies the specified control content to the applied voltage control unit 330.

[0019] The applied voltage control unit 330 controls the voltage applied to the RIS element group 340 according to the control content of the reflection angle notified from the signal processing unit 320. That is, the applied voltage control unit 330 applies a voltage to the RIS element group 340 so that the reflection angle corresponding to the pilot signal is set.

[0020] The RIS element group 340 is a plurality of RIS elements two-dimensionally arranged on the surface of the RIS 300, and has a plurality of RIS elements each composed of a variable capacitance diode or the like. The RIS element group 340 changes the reflection angle of the wireless signal in the RIS 300 by the voltage applied from the applied voltage control unit 330 to each RIS element.

[0021] FIG. 3 is a block diagram showing the configuration of the base station device 100 according to an embodiment. The base station device 100 shown in FIG. 3 includes a processor 110, a memory 120, a wireless transmission unit 130, and a wireless reception unit 140.

[0022] The processor 110 includes, for example, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or a DSP (Digital Signal Processor), and comprehensively controls the entire base station apparatus 100. Specifically, the processor 110 has a pilot signal generation unit 111, a transmission signal generation unit 112, a multiplexing unit 113, a demodulation and decoding unit 114, and a transmission method determination unit 115.

[0023] The pilot signal generation unit 111 generates pilot signals known at the terminal devices 200a and 200b from a predetermined code sequence. At this time, the pilot signal generation unit 111 generates two types of pilot signals transmitted in different directions. Specifically, the pilot signal generation unit 111 generates a first pilot signal directly transmitted in the directions of the terminal devices 200a and 200b and a second pilot signal transmitted in the direction of the RIS 300. That is, the pilot signal generation unit 111 multiplies the first pilot signal by a first antenna weight corresponding to the directions of the terminal devices 200a and 200b, and multiplies the second pilot signal by a second antenna weight corresponding to the direction of the RIS 300. Further, when generating the second pilot signal, the pilot signal generation unit 111 generates different second pilot signals for each reflection angle of the RIS 300 by circularly shifting a predetermined code sequence. The specific configuration of the pilot signal generation unit 111 will be described in detail later.

[0024] The transmission signal generation unit 112 generates a transmission signal from the control information and the transmission data. That is, the transmission signal generation unit 112 generates a transmission signal to be transmitted to the terminal devices 200a and 200b by encoding and modulating the control information and the transmission data respectively. Further, the transmission signal generation unit 112 applies (multiplies) antenna weights to the transmission signals to be transmitted to the terminal devices 200a and 200b respectively, and performs beamforming. At this time, the transmission signal generation unit 112 multiplies the transmission signal by the first antenna weight or the second antenna weight according to the transmission direction of the transmission signal. That is, when the transmission signals addressed to the terminal devices 200a and 200b are transmitted in the directions of the terminal devices 200a and 200b according to the instruction from the transmission method determination unit 115, the transmission signal generation unit 112 multiplies the transmission signal by the first antenna weight, and when the transmission signal is transmitted in the direction of the RIS 300, the transmission signal generation unit 112 multiplies the transmission signal by the second antenna weight to perform beamforming transmission.

[0025] The multiplexing unit 113 time-division multiplexes and frequency-division multiplexes the pilot signal generated by the pilot signal generation unit 111 and the transmission signal generated by the transmission signal generation unit 112. The multiplexing unit 113 outputs the multiplexed signal obtained by multiplexing the pilot signal and the transmission signal to the wireless transmission unit 130.

[0026] The demodulation and decoding unit 114 acquires the received signal from the wireless reception unit 140, and demodulates and decodes the received signal. Then, the demodulation and decoding unit 114 acquires the report information from the terminal devices 200a and 200b included in the received signal, and outputs it to the transmission method determination unit 115. The report information includes information on the received power of the pilot signal measured at each of the terminal devices 200a and 200b.

[0027] The transmission method determination unit 115 determines whether to transmit signals directly to the terminal devices 200a and 200b or to transmit signals via the RIS 300, based on the report information output from the demodulation and decoding unit 114. Specifically, the transmission method determination unit 115 determines to transmit signals directly to the terminal devices 200a and 200b for which the pilot signal with the highest received power is the first pilot signal. On the other hand, the transmission method determination unit 115 determines to transmit signals via the RIS 300 to the terminal devices 200a and 200b for which the pilot signal with the highest received power is the second pilot signal. Furthermore, when the pilot signal with the highest received power is the second pilot signal, the transmission method determination unit 115 identifies the reflection angle of the RIS 300 that corresponds to the cyclic shift amount of this second pilot signal.

[0028] Then, the transmission method determination unit 115 notifies the pilot signal generation unit 111 and the transmission signal generation unit 112 of information regarding whether to transmit signals directly to the terminal devices 200a and 200b or to transmit signals via the RIS 300. That is, the transmission method determination unit 115 instructs the pilot signal generation unit 111 and the transmission signal generation unit 112 whether to transmit signals in the direction of the terminal devices 200a and 200b or in the direction of the RIS 300. Furthermore, when transmitting signals via the RIS 300, the transmission method determination unit 115 notifies the pilot signal generation unit 111 of information regarding the amount of cyclic shift of the second pilot signal having the maximum received power.

[0029] The memory 120 includes, for example, a random access memory (RAM) or a read only memory (ROM), and stores information used in processing by the processor 110.

[0030] Radio transmitting section 130 performs predetermined radio transmission processing on the multiplexed signal output from multiplexing section 113, and transmits the result by radio via an antenna.

[0031] The wireless reception unit 140 receives a signal via an antenna and performs predetermined wireless reception processing on the received signal. Then, the wireless reception unit 140 outputs the received signal to the demodulation / decoding unit 114.

[0032] Figure 4 is a block diagram showing the configuration of the pilot signal generation unit 111. The pilot signal generation unit 111 shown in Figure 4 includes a code sequence generation unit 401, a signal formation unit 402, a weighting unit 403, a cyclic shift processing unit 404, a signal formation unit 405, a weighting unit 406, and a multiplexing unit 407.

[0033] The code sequence generation unit 401 generates a code sequence used for generating a pilot signal. The code sequence generated by the code sequence generation unit 401 is also known in the terminal devices 200a and 200b. The code sequence generation unit 401 outputs the generated code sequence to the signal formation unit 402 and the cyclic shift processing unit 404.

[0034] The signal formation unit 402 forms a first pilot signal that is directly transmitted in the directions of the terminal devices 200a and 200b using the code sequence.

[0035] The weighting unit 403 applies (multiplies) a first antenna weight for forming a beam in the directions of the terminal devices 200a and 200b to the first pilot signal.

[0036] The cyclic shift processing unit 404 cyclically shifts the code sequence. Specifically, the cyclic shift processing unit 404 cyclically shifts each bit constituting the code sequence to generate a plurality of code sequences with different cyclic shift amounts. The cyclic shift amounts of these code sequences correspond one-to-one to the reflection angles in the RIS 300. That is, the plurality of code sequences generated by the cyclic shift processing unit 404 by cyclic shift correspond to different reflection angles in the RIS 300. Note that when the cyclic shift amount of the second pilot signal with the maximum received power is notified from the transmission method determination unit 115, the cyclic shift processing unit 404 generates a code sequence cyclically shifted by the notified cyclic shift amount.

[0037] The signal forming unit 405 forms a second pilot signal transmitted in the direction of the RIS 300 by using the code sequence circularly shifted by the circular shift processing unit 404. That is, the signal forming unit 405 forms a second pilot signal corresponding to the reflection angle from code sequences corresponding to different reflection angles.

[0038] The weighting unit 406 applies (multiplies) a second antenna weight for forming a beam in the direction of the RIS 300 to the second pilot signal.

[0039] The multiplexing unit 407 time-division multiplexes and frequency-division multiplexes the first pilot signal and the second pilot signal. Specifically, the multiplexing unit 407 time-division multiplexes, for example, second pilot signals with different circular shift amounts, and frequency-division multiplexes the first pilot signal and the second pilot signals. Then, the multiplexing unit 407 outputs a pilot signal including the first pilot signal and the second pilot signal to the multiplexing unit 113.

[0040] In this way, the pilot signal generation unit 111 generates a pilot signal including a first pilot signal transmitted in the directions of the terminal devices 200a and 200b and a plurality of second pilot signals transmitted in the direction of the RIS 300 and having different circular shift amounts.

[0041] FIG. 5 is a block diagram showing the configuration of the terminal device 200 according to an embodiment. The terminal device 200 has the same configuration as the terminal devices 200a and 200b. The terminal device 200 shown in FIG. 5 includes a wireless reception unit 210, a wireless transmission unit 220, a processor 230, and a memory 240.

[0042] The wireless reception unit 210 receives a wireless signal transmitted from the base station device 100 via an antenna, and performs predetermined wireless reception processing on the received signal. Then, the wireless reception unit 210 outputs the received signal to the processor 230.

[0043] The wireless transmission unit 220 performs predetermined wireless transmission processing on the signal output from the processor 230, and wirelessly transmits it via an antenna.

[0044] The processor 230 includes, for example, a CPU, an FPGA, or a DSP, and comprehensively controls the entire terminal device 200. Specifically, the processor 230 includes a control information demodulation / decoding unit 231, a replica generation unit 232, a pilot signal detection unit 233, a received power measurement unit 234, a maximum power determination unit 235, a report information generation unit 236, and an encoding / modulation unit 237.

[0045] The control information demodulation / decoding unit 231 acquires control information included in the received signal by demodulating and decoding the received signal. The control information includes information on the code sequence used for generating the pilot signal, information on the timing at which the first pilot signal and the second pilot signal are transmitted, and the like.

[0046] The replica generation unit 232 generates replicas of the first pilot signal and the second pilot signal based on the control information. Specifically, the replica generation unit 232 generates replicas equivalent to the first pilot signal and the second pilot signal generated in the base station device 100 from the information on the code sequence included in the control information. At this time, the replica generation unit 232 generates replicas of the second pilot signal with different cyclic shift amounts.

[0047] The pilot signal detection unit 233 detects the pilot signal from the received signal using the replicas generated by the replica generation unit 232. That is, the pilot signal detection unit 233 detects the first pilot signal and the second pilot signal with different cyclic shift amounts from the received signal by, for example, performing a correlation operation between the received signal and the replica.

[0048] The received power measurement unit 234 measures the received power of the first pilot signal and the second pilot signal with different cyclic shift amounts. Therefore, the received power measurement unit 234 measures the received power of the first pilot signal directly received from the base station device 100 and the received power of the second pilot signal reflected at different reflection angles in the RIS 300.

[0049] Maximum power identifying unit 235 identifies the maximum received power from the received power measured by received power measuring unit 234. That is, maximum power identifying unit 235 identifies the pilot signal with the maximum received power from among the first pilot signal and the second pilot signals each having a different amount of cyclic shift.

[0050] The report information generator 236 generates report information including information on the received power of the first pilot signal and the second pilot signal having different amounts of cyclic shift, and information specifying the pilot signal with the maximum received power.

[0051] The encoding and modulation unit 237 encodes and modulates the report information generated by the report information generation unit 236 and causes the radio transmission unit 220 to transmit the encoded and modulated report information to the base station apparatus 100 .

[0052] The memory 240 includes, for example, a RAM or a ROM, and stores information used in processing by the processor 230.

[0053] Next, a wireless communication method in the wireless communication system configured as above will be described with reference to the sequence diagram shown in FIG.

[0054] In the base station apparatus 100, a pilot signal is generated using a predetermined code sequence (step S101). Specifically, a first pilot signal is generated from the code sequence, and multiple second pilot signals are generated from code sequences that have been cyclically shifted by different cyclic shift amounts. That is, as shown in FIG. 7, for example, a first pilot signal is generated from a code sequence with a cyclic shift amount of 0, and second pilot signals are generated from code sequences with cyclic shift amounts of 4, 8, and 12. In the example shown in FIG. 7, a 16-bit code sequence is cyclically shifted by 4 bits. For example, in a code sequence with a cyclic shift amount of 4, the last 4 bits A12 to A15 of the code sequence with a cyclic shift amount of 0 are cyclically shifted to the beginning. The cyclic shift amount corresponds to the reflection angle set in the RIS 300, and second pilot signals generated from code sequences with cyclic shift amounts of 4, 8, and 12 correspond to different reflection angles.

[0055] When the first pilot signal and the second pilot signal are generated, the second pilot signal is transmitted to the RIS 300 (step S102). Here, the second pilot signal corresponding to any one of the reflection angles is transmitted. When the second pilot signal is received by the RIS 300, the reflection angle corresponding to the cyclic shift amount of the second pilot signal is set (step S103). That is, in the RIS 300, the voltage applied to the RIS element group 340 is controlled according to the cyclic shift amount of the received second pilot signal, and the reflection angle of the radio signal in the RIS 300 is adjusted. That is, this second pilot signal functions as a control signal for controlling the reflection angle of the RIS 30).

[0056] After the second pilot signal is transmitted, the same second pilot signal is transmitted to the RIS 300 (step S104). Here, since the reflection angle of the RIS 300 is adjusted, the second pilot signal is reflected at the adjusted reflection angle in the RIS 300. At the same time as the transmission of the second pilot signal, the first pilot signal is transmitted to the terminal device 200 (step S105). That is, the transmission of the first pilot signal and the second transmission of the second pilot signal are executed simultaneously.

[0057] The first pilot signal and the second pilot signal reflected by the RIS 300 are received by the terminal device 200. Then, in the terminal device 200, the first pilot signal and the second pilot signal are detected from the received signal, and the received powers of the first pilot signal and the second pilot signal are measured (step S106).

[0058] The adjustment of the reflection angle of the RIS 300 by transmitting the second pilot signal in steps S102 to S106 and the measurement of the received power of the first pilot signal and the second pilot signal are repeated for each of the second pilot signals with different cyclic shift amounts. That is, for example, as shown in FIG. 8, in the odd-numbered slots such as slot #1, #3, #5, etc., second pilot signals with different cyclic shift amounts are transmitted as control signals for adjusting the reflection angle of the RIS 300. Then, in the even-numbered slots such as slot #2, #4, #6, etc., the same second pilot signal as the second pilot signal transmitted in the immediately preceding odd-numbered slot is transmitted, and the first pilot signal is transmitted. The terminal device 200 receives the first pilot signal and the second pilot signal in the even-numbered slot and measures the received power. Thereby, in the terminal device 200, it becomes possible to measure the received power of the first pilot signal transmitted in the direction of the terminal device 200 and a plurality of second pilot signals reflected at different reflection angles in the RIS 300.

[0059] When the received power of the first pilot signal and a plurality of second pilot signals with different cyclic shift amounts is measured, in the terminal device 200, the pilot signal with the maximum received power is specified, and the received power of each pilot signal and the reporting information regarding the pilot signal with the maximum received power are generated (step S107). Then, the reporting information is transmitted to the base station device 100 (step S108).

[0060] When the reporting information is received by the base station apparatus 100, it is determined whether to transmit a signal directly to the terminal apparatus 200 or to transmit a signal via the RIS 300 (step S109). That is, when the reception power of the first pilot signal is the maximum, it is determined that a signal is transmitted directly from the base station apparatus 100 to the terminal apparatus 200. On the other hand, when the reception power of the second pilot signal is the maximum, it is determined that a signal is transmitted from the base station apparatus 100 to be reflected by the RIS 300 and then to the terminal apparatus 200. Also, from the cyclic shift amount of the second pilot signal with the maximum reception power, the optimal reflection angle in the RIS 300 is specified. That is, the reflection angle of the RIS 300 at which the reception power of the second pilot signal becomes the maximum is specified. Then, the base station apparatus 100 forms a beam in the determined direction, and when performing transmission via the RIS 300, adjusts the reflection angle of the RIS 300 to the optimal reflection angle and performs wireless communication with the terminal apparatus 200.

[0061] As described above, according to the present embodiment, the base station apparatus transmits the first pilot signal transmitted directly in the direction of the terminal apparatus and the second pilot signal different for each reflection angle in the RIS, receives the report of the reception power of the pilot signal in the terminal apparatus, and determines the transmission method corresponding to the pilot signal with the maximum reception power. For this reason, it is possible to appropriately determine whether to transmit a signal directly to the terminal apparatus or to transmit a signal via the RIS, and when transmitting a signal via the RIS, it is possible to set the optimal reflection angle in the RIS. As a result, the wireless quality can be improved.

[0062] In the above-described embodiment, it is assumed that the first pilot signal and the second pilot signal are generated using the same code sequence. However, the first pilot signal and the second pilot signal may be generated using different code sequences, respectively.

[0063] Fig. 9 is a block diagram showing a modified example of pilot signal generating section 111 of base station apparatus 100. In Fig. 9, the same components as in Fig. 4 are assigned the same reference numerals, and their description will be omitted. Pilot signal generating section 111 shown in Fig. 9 has code sequence generating sections 451 and 452 instead of code sequence generating section 401 of the pilot signal generating section shown in Fig. 4.

[0064] The code sequence generator 451 generates a code sequence used to generate a first pilot signal. The code sequence generated by the code sequence generator 451 is also known to the terminal devices 200a and 200b. The code sequence generator 451 outputs the generated code sequence to the signal forming unit 402.

[0065] The code sequence generator 452 generates a code sequence used to generate a second pilot signal. The code sequence generated by the code sequence generator 452 is also known to the terminal devices 200a and 200b. The code sequence generator 452 outputs the generated code sequence to the cyclic shift processor 404.

[0066] 9, the first pilot signal and the second pilot signal are generated using different code sequences. Even in this case, the second pilot signal is generated by cyclically shifting the code sequence by a different amount of cyclic shift for each reflection angle in the RIS 300.

[0067] In the above embodiment, the second pilot signal is used as a control signal for controlling the reflection angle of the RIS 300, but the second pilot signal does not necessarily have to be used as the control signal. That is, for example, in FIG. 8, the control signal for controlling the reflection angle may be transmitted in odd-numbered slots #1, #3, #5, etc., and the first pilot signal and the second pilot signal may be transmitted in even-numbered slots #2, #4, #6, etc. Even in this case, the terminal device 200 receives the first pilot signal and the second pilot signal in the even-numbered slots and measures the received power. [Explanation of symbols]

[0068] 110, 230 processors 111 Pilot signal generator 112 Transmission signal generation unit 113 Multiplex section 114 Demodulation and Decoding Unit 115 Transmission method determination unit 120, 240 memory 130, 220 Radio transmitter 140, 210 Radio receiving unit 231 Control information demodulation and decoding unit 232 Replica Generation Unit 233 Pilot signal detector 234 Received power measurement unit 235 Maximum power specification section 236 Report information generation section 237 Encoding and Modulation Section 401, 451, 452 code string generator 402, 405 Signal forming section 403, 406 Weight assignment section 404 Cyclic Shift Processing Unit

Claims

[

1. ] A base station apparatus comprising: a processor that generates a first pilot signal and a plurality of second pilot signals, multiplies the first pilot signal by a first antenna weight, and multiplies the plurality of second pilot signals by a second antenna weight; a wireless transmission unit that transmits the first pilot signal to a terminal device and transmits the plurality of second pilot signals to a communication device having a function of changing a reflection angle of a wireless signal; a wireless reception unit that receives a measurement result of the first pilot signal and a second pilot signal among the plurality of second pilot signals from the terminal device and characterized in that: the processor generates the first pilot signal using a symbol sequence, and generates the plurality of second pilot signals by circularly shifting the symbol sequence. [

2. ] A base station apparatus comprising: a processor that generates a first pilot signal and a plurality of second pilot signals, multiplies the first pilot signal by a first antenna weight, and multiplies the plurality of second pilot signals by a second antenna weight; a wireless transmission unit that transmits the first pilot signal to a terminal device and transmits the plurality of second pilot signals to a communication device having a function of changing a reflection angle of a wireless signal; a wireless reception unit that receives a measurement result of the first pilot signal and a second pilot signal among the plurality of second pilot signals from the terminal device and characterized in that: the processor generates the first pilot signal using a first symbol sequence, and generates the plurality of second pilot signals by circularly shifting a second symbol sequence. [

3. ] The processor associates the amount of the circular shift with the content of signal processing of a device that receives the plurality of second pilot signals. The base station apparatus according to claim 1 or 2, characterized in that. [

4. ] A base station apparatus comprising: a processor that generates a first pilot signal and a plurality of second pilot signals, multiplies the first pilot signal by a first antenna weight, and multiplies the plurality of second pilot signals by a second antenna weight; a wireless transmission unit that transmits the first pilot signal to a terminal device and transmits the plurality of second pilot signals to a communication device having a function of changing a reflection angle of a wireless signal; a wireless reception unit that receives a measurement result of the first pilot signal and a second pilot signal among the plurality of second pilot signals from the terminal device having, the wireless transmission unit transmits the first pilot signal and the second pilot signal in the same slot, among the plurality of second pilot signals, other second pilot signals are transmitted in slots before the same slot, and the other second pilot signals are used as control signals for adjusting the reflection angle of the communication device A base station apparatus characterized by the above.

5. further comprising a wireless reception unit that receives information regarding the reception power of the first pilot signal and the plurality of second pilot signals in a terminal device, the processor, determines a transmission method for transmitting a wireless signal to the terminal device based on the information received by the wireless reception unit, causes the wireless transmission unit to transmit a wireless signal according to the determined transmission method The base station apparatus according to any one of claims 1, 2, and 4, characterized by the above.

6. the processor, determines to multiply the first antenna weight by the wireless signal addressed to the terminal device when the reception power of the first pilot signal is maximum The base station apparatus according to claim 5, characterized by the above.

7. the processor, determines to multiply the second antenna weight by the wireless signal addressed to the terminal device when the reception power of any one of the plurality of second pilot signals is maximum The base station apparatus according to claim 5, characterized by the above.

8. the processor, when the reception power of any one of the plurality of second pilot signals is maximum, sets the content of signal processing associated with the second pilot signal with the maximum reception power in the device that receives the plurality of second pilot signals The base station apparatus according to claim 5, characterized by the above.

9. A wireless communication system having a base station apparatus, a terminal device that wirelessly communicates with the base station apparatus, and a communication device having a function of changing the reflection angle of a wireless signal, the base station apparatus, a first processor that generates a first pilot signal and a plurality of second pilot signals, multiplies the first pilot signal by a first antenna weight, and multiplies the plurality of second pilot signals by a second antenna weight, a wireless transmission unit that transmits the first pilot signal in the direction of the terminal device and transmits the plurality of second pilot signals to the communication device A radio receiving unit that receives measurement results of the first pilot signal and a second pilot signal among the plurality of second pilot signals from the terminal device and has The terminal device A radio receiving unit that receives the first pilot signal and the plurality of second pilot signals, A second processor that measures reception powers of the first pilot signal and the plurality of second pilot signals and generates report information including the measurement results of the reception powers, A second radio transmitting unit that transmits the report information generated by the second processor to the base station device, The first processor Generates the first pilot signal using a code sequence, Circularly shifts the code sequence to generate the plurality of second pilot signals A wireless communication system characterized by the above.

10. A wireless communication method in a wireless communication system including a base station device, a terminal device that wirelessly communicates with the base station device, and a communication device having a function of changing a reflection angle of a wireless signal, The base station device Generates a first pilot signal and a plurality of second pilot signals, multiplies the first pilot signal by a first antenna weight, and multiplies the plurality of second pilot signals by a second antenna weight, Transmits the first pilot signal in the direction of the terminal device and transmits the plurality of second pilot signals to the communication device, The terminal device Receives the first pilot signal and the plurality of second pilot signals, Measures reception powers of the first pilot signal and the plurality of second pilot signals, Generates report information including the measurement results of the reception powers, Transmits the report information to the base station device having a process, The first pilot signal is generated using a code sequence, The plurality of second pilot signals are generated by circularly shifting the code sequence. A wireless communication method characterized by the above.

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