Direction estimation device, wireless communication method, direction estimation method, and program

Abstract

To enable accurate estimation of a radio wave propagation direction.SOLUTION: A direction estimation device is provided, comprising an acquisition unit for acquiring information on received power of multiple beams received via a propagation path, a computation unit for computing degrees of similarity between the received power of the multiple beams and a beam gain for multiple directions, and an estimation unit for estimating a propagation direction of a radio wave in the propagation path on the basis of the computed degrees of similarity.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a direction estimation device, a wireless communication device, a direction estimation method, and a program in a wireless communication system.

Background Art

[0002] In a wireless communication system such as a fifth-generation (5G) mobile communication system, beamforming for transmitting and receiving radio waves in a specific direction is used to improve the reception quality of radio waves. In order to obtain the effect of improving the reception quality by beamforming, it is necessary to form a beam according to the propagation direction of the radio wave in the propagation path.

[0003] As a method for estimating the propagation direction of a radio wave with a large received power, there is a method of transmitting and receiving a reference signal while forming beams in a plurality of directions and obtaining the direction in which the received power of the reference signal is maximum. However, in this method, there is a problem of a trade-off between the estimation accuracy of the propagation direction and the processing time and power consumption. That is, if the number of beams is increased and the beam interval is narrowed, the estimation accuracy of the propagation direction will be high, but the processing time and power consumption required for processing will increase. On the contrary, if the number of beams is decreased and the beam interval is widened, the processing time and power consumption can be reduced, but the estimation accuracy of the propagation direction will be low.

[0004] As a related art, Patent Document 1 discloses a beam generation method. The beam generation device described in Patent Document 1 derives a first reception beam in which a reception signal having the largest size is received from a terminal and a second reception beam in which a reception signal having the second largest size is received from the terminal among a large number of reception beams. The beam generation device estimates the direction of the terminal based on the ratio value between the size of the reception signal received via the first reception beam and the size of the reception signal received via the second reception beam. That is, the beam generation device described in Patent Document 1 estimates the beam propagation direction based on the reception power ratio of two beams with large reception power of the reference signal.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The beam generation device described in Patent Document 1 can improve the estimation accuracy of the propagation direction of radio waves without increasing the number of beams. However, in the beam generation device described in Patent Document 1, the estimated value of the propagation direction is limited to the line connecting the directions of two beams with large received power. Therefore, when the propagation direction is not on the line connecting the directions of two beams with large received power, there is a possibility that the estimation error of the propagation direction is large.

[0007] One of the objects of the present disclosure is to provide a direction estimation device, a wireless communication device, a direction estimation method, and a program capable of estimating the propagation direction of radio waves with high accuracy.

Means for Solving the Problems

[0008] The direction estimation device according to the first aspect of the present disclosure includes an acquisition unit that acquires information regarding the received power of a plurality of beams received via a propagation path, a calculation unit that calculates the similarity between the received power of the plurality of beams and the beam gain for a plurality of directions, and an estimation unit that estimates the propagation direction of radio waves in the propagation path based on the similarity.

[0009] The wireless communication device according to the second aspect of the present disclosure includes the above-described direction estimation device and a generation unit that generates a beamforming weight based on the propagation direction of the radio waves.

[0010] The direction estimation method according to the third aspect of the present disclosure includes obtaining information regarding the reception power of a plurality of beams received via a propagation path, calculating the similarity between the reception power of the plurality of beams and the beam gain for a plurality of directions, and estimating the propagation direction of radio waves in the propagation path based on the similarity.

[0011] The program according to the fourth aspect of the present disclosure is for causing a computer to execute a process including obtaining information regarding the reception power of a plurality of beams received via a propagation path, calculating the similarity between the reception power of the plurality of beams and the beam gain for a plurality of directions, and estimating the propagation direction of radio waves in the propagation path based on the similarity.

Advantages of the Invention

[0012] According to one aspect of the present disclosure, the estimation accuracy of the propagation direction of radio waves can be improved.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0014] (First Embodiment) A first embodiment of the present disclosure will be described. FIG. 1 shows a configuration example of a first direction estimation apparatus according to the present disclosure. The direction estimation apparatus 10 shown in FIG. 1 includes an acquisition unit 11, a calculation unit 12, and an estimation unit 13. FIG. 2 shows an operation procedure of the direction estimation apparatus 10.

[0015] The acquisition unit 11 acquires information regarding the reception power of a plurality of beams (step S11). The calculation unit 12 calculates the similarity between the reception power of the plurality of beams acquired by the acquisition unit 11 and the beam gain for a plurality of directions (step S12). The estimation unit 13 estimates the propagation direction of the radio wave based on the similarity calculated by the calculation unit 12 (step S13).

[0016] In the present embodiment, it is assumed that a plurality of antenna elements are used for forming a plurality of beams. The beam gain means, for example, a gain obtained by synthesizing signals of a plurality of antenna elements used for beam forming. The beam gain may also be referred to as a beamforming gain or an array gain. The beam gain is defined, for example, as a gain compared to the gain of a single antenna element.

[0017] For example, consider a case where a plurality of beams having mutually different beam directions are transmitted from a wireless communication device such as a base station device and a wireless terminal receives the plurality of beams. In that case, the reception power of a certain beam at the wireless terminal is represented by the product of the transmission power of the wireless communication device, the beam gain of that beam, and the path gain in a one-path environment. Therefore, in a one-path environment, the reception power of each beam is proportional to the beam gain of each beam. Similarly, when a wireless signal transmitted from a wireless terminal is received by a wireless communication terminal device using a plurality of beams, the reception power of each beam is proportional to the beam gain of each beam.

[0018] The direction estimation device 10 in this embodiment acquires information regarding the reception power of a plurality of beams, and calculates the similarity between the reception power of the acquired plurality of beams and the beam gain for a plurality of directions. The direction estimation device 10 estimates the propagation direction of the radio wave based on the calculated similarity. The direction estimation device 10 utilizes the above-described relationship that the reception power of each beam is proportional to the beam gain of each beam, and estimates the propagation direction of the radio wave based on the similarity between the reception power of the plurality of beams and the beam gain calculated for a plurality of directions. The direction estimation device 10 determines, for example, the direction with a high similarity as the path direction, that is, the propagation direction of the radio wave. By doing so, the direction estimation device 10 can estimate the propagation direction of the radio wave without depending on the direction of the beam for acquiring the reception power information. Therefore, the direction estimation device 10 can improve the estimation accuracy of the propagation direction of the radio wave without increasing the number of beams for acquiring the reception power information.

[0019] (Second Embodiment) Next, a second embodiment of the present disclosure will be described. In this embodiment, a wireless communication system in which the direction estimation device 10 described in the first embodiment is used will be described. In this embodiment, the wireless communication system is, for example, a system compliant with the technical specifications of 3GPP (Third Generation Partnership Project). The wireless communication system may be a system compliant with the technical specifications of 5G (Fifth generation), or may be a system compliant with the technical specifications of 4G (Fourth generation), or may be a system compliant with the technical specifications of 3G. The wireless communication system is not limited to the above-described systems, and may be a system compliant with technical specifications different from those of 3GPP.

[0020] <Configuration of Wireless Communication System> Figure 3 shows a configuration example of the wireless communication system according to the present disclosure. The wireless communication system 1 includes a wireless communication device 20. As shown in FIG. 3, the wireless communication system 1 includes a wireless communication device 20 and a wireless terminal 30. Note that in FIG. 3, an example is shown in which the wireless communication system 1 has one wireless communication device 20 and one wireless terminal 30. However, the present embodiment is not limited to this. The wireless communication system 1 may have a plurality of wireless communication devices 20. Also, the wireless communication system 1 may have a plurality of wireless terminals 30.

[0021] The wireless communication device 20 is a device capable of performing wireless communication with the wireless terminal 30. The wireless communication device 20 may be, for example, a node of a radio access network (RAN). The wireless communication device 20 may be a BTS (Base Transceiver Station), a NodeB, an eNodeB (evolved NodeB), or a gNodeB (next generation NodeB). Also, the wireless communication device 20 may be a relay device having a relay function.

[0022] As shown in FIG. 3, the wireless communication device 20 can form a plurality of beams 1 to B. Here, B is an integer of 2 or more. For forming a plurality of beams, for example, an array antenna in which a plurality of antenna elements are arranged in an array is used. The wireless terminal 30 is configured as a portable terminal device such as a smartphone, a mobile phone, or a tablet, for example. The wireless terminal 30 may be a relay device having a relay function. The wireless terminal 30 may also be called a user equipment (UE) or a mobile station.

[0023] In the following description, the link through which a signal is transmitted from the wireless communication device 20 to the wireless terminal 30 is called the "downlink". Also, the signal transmitted on the downlink is called the "downlink signal". Further, the link through which a signal is transmitted from the wireless terminal 30 to the wireless communication device 20 is called the "uplink". Also, the signal transmitted on the uplink is called the "uplink signal".

[0024] <Configuration of Wireless Communication Device> FIG. 4 shows the configuration of the wireless communication device 20. The wireless communication device 20 includes a received signal processing unit 21, a direction estimation device 22, a beamforming weight generation unit 23, and a transmitted signal processing unit 24.

[0025] The wireless terminal 30 receives the downlink signal transmitted using a plurality of beams 1 to B. When the wireless terminal 30 receives the downlink signal, it measures information regarding the received power of the beams 1 to B. The information regarding the received power of the beams 1 to B may be, for example, the received power (RSRP: Reference Signal Received Power) of the reference signal of the downlink transmitted by the wireless communication device 20. Alternatively, the information regarding the received power of the beams 1 to B may be the received quality (RSRQ: Reference Signal Received Quality) of the reference signal of the downlink. The information regarding the received power of the beams 1 to B may be the received signal strength (RSSI: Received Signal Strength Indicator) of the reference signal of the downlink. The information regarding the received power of the beams 1 to B may be the signal-to-interference plus noise ratio (SINR: Signal to Interference plus Noise Ratio) of the reference signal of the downlink. The wireless terminal 30 can transmit an uplink signal including the measured information regarding the received power of the beams 1 to B to the wireless communication device 20.

[0026] The receiving signal processing unit 21 performs reception processing of the uplink signal transmitted by the wireless terminal 30. For example, the receiving signal processing unit 21 receives an uplink signal including information on the reception power of beams 1 to B. The receiving signal processing unit 21 performs demodulation and decoding processing on the received uplink signal to obtain information on the reception power of beams 1 to B in the wireless terminal 30. Alternatively, the receiving signal processing unit 21 may receive the uplink signal using each of beams 1 to B and measure the reception power of beams 1 to B. In that case, the uplink signal may not include information on the reception power of beams 1 to B. The receiving signal processing unit 21 transmits the obtained information on the reception power of beams 1 to B to the direction estimation device 22.

[0027] The direction estimation device 22 estimates the propagation direction of radio waves. The direction estimation device 22 has, for example, the same configuration as the direction estimation device 10 shown in FIG. 1. In the direction estimation device 22, the acquisition unit 11 acquires information on the reception power of beams 1 to B from the receiving signal processing unit 21 and outputs the reception power of beams 1 to B to the calculation unit 12. Note that the acquisition unit 11 may perform part of the processing necessary for deriving the reception power of beams 1 to B instead of the receiving signal processing unit 21.

[0028] In the direction estimation device 22, the calculation unit 12 calculates the similarity between the reception power of beams 1 to B and the beam gain for a plurality of directions using the reception power of beams 1 to B acquired by the acquisition unit 11. The calculation unit 12 may calculate or measure the beam gains of beams 1 to B in advance. For example, the beam gain of beam b (b is an integer from 1 to B) may be calculated by the product of the beamforming weight vector and the steering vector of beam b. Alternatively, the beam gains of beams 1 to B may be derived by measuring the reception power of beams 1 to B while changing the measurement position.

[0029] An example of the similarity calculated by the calculation unit 12 will be described using a mathematical formula. Here, the reception power of beam b is represented as r b and the reception power vector having the reception power of beams 1 to B as elements is represented as r. The reception power vector r can be represented by the following formula (1). In the above formula (1), the superscript character T represents transpose. If there is a beam among beams 1 to B for which the received power has not been acquired, a predetermined value may be substituted for the received power of that beam.

[0030] The beam gain of beam b with respect to the azimuth angle φ and the elevation angle θ is denoted as g b (φ, θ), and the beam gain vector having the beam gains of beams 1 to B with respect to the azimuth angle φ and the elevation angle θ as elements is denoted as g(φ, θ). The azimuth angle φ can be defined, for example, such that the front direction of the array antenna used for forming a plurality of beams is 0 degrees. The elevation angle θ can be defined, for example, as the angle in the vertical direction with respect to the horizontal as viewed from the center of the array antenna. The beam gain vector g(φ, θ) can be expressed by the following formula (2). The calculation unit 12 stores the beam gain vector g(φ, θ) for a plurality of combinations of the azimuth angle φ and the elevation angle θ.

[0031] The similarity between the received power and the beam gain of beams 1 to B with respect to the azimuth angle φ and the elevation angle θ is denoted as ρ(φ, θ). As an example, when the similarity is the cosine similarity, the similarity ρ(φ, θ) with respect to the azimuth angle φ and the elevation angle θ can be expressed by the following formula (3). However, || || represents the norm of a vector. The calculation unit 12 calculates the similarity ρ(φ, θ) for a plurality of directions, that is, for a plurality of combinations of the azimuth angle φ and the elevation angle θ.

[0032] Another example of the similarity calculated by the calculation unit 12 will be described using mathematical expressions. As described above, in the case of a one-path environment, the received power of each beam is proportional to the beam gain of each beam. Therefore, if the azimuth angle and elevation angle of the path are φ' and θ' respectively, r b = αg b (φ', θ') can be expressed. However, α is a proportionality coefficient. From this, the following relational expression of formula (4) holds between any two beams, for example, beam b and beam c. TIFF2025100287000005.tif1662

[0033] The above formula (4) means that the ratio of the received power is equal to the ratio of the beam gains with respect to the azimuth angle φ' and the elevation angle θ' between any two beams. That is, when estimating the path direction, i.e., the radio wave propagation direction, it is only necessary to find the direction in which the ratio of the received power between two beams is equal to the ratio of the beam gains. Therefore, the similarity ρ(φ,θ) with respect to the azimuth angle φ and the elevation angle θ can be expressed, for example, by the following formula (5). TIFF2025100287000006.tif22110In the above formula (5), N is an integer greater than or equal to 2 and less than or equal to B. The above formula (5) means that the smaller the difference between the ratio of the received power and the ratio of the beam gains between two beams, the closer the similarity is to 1.

[0034] Note that in the above formula (5), the similarity is calculated based on the received power and the beam gains of beams 1 to N, but the present disclosure is not limited to this example. For example, the calculation unit 12 may select N beams from B beams (beams 1 to B) and calculate the similarity based on the received power and the beam gains of the selected N beams. As an example, the calculation unit 12 may select N beams in descending order of received power among beams 1 to beam B and calculate the similarity based on the received power and the beam gains of the selected N beams. The value of N above may be variable according to the value of the received power of the beams. The calculation unit 12 may select N beams from the B beams, where the ratio of the received power between two beams is equal to or greater than a predetermined threshold value, and calculate the similarity based on the received power and the beam gains of the selected beams.

[0035] When the propagation direction of radio waves is limited due to the influence of the position, orientation, directivity, etc. of the antenna included in the wireless communication device 20, the calculation unit 12 may omit the calculation or measurement of the beam gain for the direction in which it is estimated that radio waves do not propagate. Alternatively, for the direction in which it is estimated that radio waves do not propagate, the calculation unit 12 may substitute an invalid value or a zero value for the beam gain. For the direction in which it is estimated that radio waves do not propagate, the calculation unit 12 may omit the calculation of the similarity, or may substitute an invalid value or a zero value for the similarity.

[0036] For any of the beams 1 to B, when the main lobe is not facing the direction, the calculation unit 12 may substitute an invalid value or a zero value for the beam gain, may omit the calculation of the similarity, or may substitute an invalid value or a zero value for the similarity. Alternatively, for areas other than the vicinity of the direction of the beam with the maximum received power, the calculation unit 12 may omit the calculation of the similarity, or may substitute an invalid value or a zero value for the similarity.

[0037] The calculation unit 12 may perform correction processing on the received power of the beams 1 to B in consideration of the transmission and reception beams of the wireless terminal 30. Since the direction estimation device 22 utilizes the similarity between the received power of the beams 1 to B and the beam gain, it is desirable that the transmission and reception beams of the wireless terminal 30 do not affect the received power. Therefore, for example, when the transmission and reception beams of the wireless terminal 30 are selected so that the received power is maximized for each of the beams 1 to B, the calculation unit 12 may select the beam with the maximum received power among the beams 1 to B as the reference beam. In that case, for a beam whose transmission and reception beam of the wireless terminal 30 is different from the reference beam, the calculation unit 12 may subtract the value of the received power by a predetermined value.

[0038] The calculation unit 12 outputs the calculated similarity to the estimation unit 13. The estimation unit 13 estimates the propagation direction of radio waves in the propagation path between the wireless communication device 20 and the wireless terminal 30 using the similarity output from the calculation unit 12.

[0039] The estimation unit 13 may estimate, for example, the azimuth angle φ and the elevation angle θ that maximize the similarity ρ(φ,θ) among a plurality of combinations of the azimuth angle φ and the elevation angle θ as the radio wave propagation direction. Alternatively, the estimation unit 13 may estimate, as the radio wave propagation direction, a value obtained by weighted averaging of the surrounding directions with the similarity around the azimuth angle φ and the elevation angle θ that maximize the similarity ρ(φ,θ). When the maximum value of the similarity is below a predetermined threshold, the estimation unit 13 may estimate the direction of the beam with the maximum received power as the radio wave propagation direction. The radio wave propagation direction is not necessarily limited to one, and the estimation unit 13 may select, for example, a plurality of directions in descending order of similarity as the radio wave propagation directions.

[0040] The estimation unit 13 outputs the estimated radio wave propagation direction to the beamforming weight generation unit 23. The beamforming weight generation unit 23 generates a beamforming weight based on the radio wave propagation direction output from the direction estimation device 22. The beamforming weight generation unit 23 outputs the generated beamforming weight to the reception signal processing unit 21 or the transmission signal processing unit 24.

[0041] When the beamforming weight is output from the beamforming weight generation unit 23 to the reception signal processing unit 21, the reception signal processing unit 21 performs reception processing of the uplink signal transmitted by the wireless terminal 30 using the output beamforming weight. When the beamforming weight is output from the beamforming weight generation unit 23 to the transmission signal processing unit 24, the transmission signal processing unit 24 performs transmission processing of the downlink signal transmitted to the wireless terminal 30 using the output beamforming weight.

[0042] <Operation of the wireless communication device> FIG. 5 shows the operation flow of the wireless communication device 20. With reference to FIG. 5, the operation of the wireless communication device 20 will be described. The reception signal processing unit 21 receives the uplink signal transmitted by the wireless terminal 30 (step S21). For example, the uplink signal received in step S21 includes information regarding the reception power of beams 1 to B measured by the wireless terminal 30. In that case, the reception signal processing unit 21 performs demodulation and decoding processing on the uplink signal to obtain information regarding the reception power of beams 1 to B in the wireless terminal 30. Alternatively, the reception signal processing unit 21 may receive the uplink signal using each of beams 1 to B and measure the reception power of beams 1 to B.

[0043] In the direction estimation device 22, the acquisition unit 11 acquires information regarding the reception power of beams 1 to B from the reception signal processing unit 21 (step S22). The calculation unit 12 calculates the similarity between the reception power of beams 1 to B and the beam gain for a plurality of directions using the information regarding the reception power of beams 1 to B (step S23). The estimation unit 13 estimates the propagation direction of radio waves in the propagation path between the wireless communication device 20 and the wireless terminal 30 using the similarities calculated by the calculation unit 12 for a plurality of directions (step S24).

[0044] The beamforming weight generation unit 23 generates a beamforming weight based on the propagation direction of radio waves estimated by the direction estimation device 22 (step S25). The beamforming weight generation unit 23 may generate a beamforming weight for transmitting a downlink signal to the wireless terminal 30 or receiving an uplink signal so as to face the estimated propagation direction of radio waves. Alternatively, the beamforming weight generation unit 23 may change the direction or shape of beams 1 to B based on the estimated propagation direction of radio waves.

[0045] For example, the beamforming weight generation unit 23 may change the directions and shapes of beams 1 to B so as to correspond to the distribution of the wireless terminals 30 based on the propagation directions of radio waves for a plurality of wireless terminals 30 and a plurality of times. Alternatively, the beamforming weight generation unit 23 may change the directions and shapes of beams 1 to B so as to mitigate the bias in the received power of the wireless terminals 30 in consideration of the received power of the wireless terminals 30.

[0046] <Effect> As described above, in the wireless communication system 1 of the second embodiment, the wireless communication device 20 acquires information regarding the received power of a plurality of beams, and calculates the similarity between the received power of the plurality of beams and the beam gain for a plurality of directions. The wireless communication device 20 estimates the propagation direction of radio waves in the propagation path between the wireless communication device 20 and the wireless terminal 30 based on the similarity. For this reason, the wireless communication device 20 can estimate the propagation direction of radio waves without depending on the direction of the beam for acquiring the information on the received power. Therefore, the wireless communication device 20 can improve the estimation accuracy of the propagation direction of radio waves without increasing the number of beams for acquiring the information on the received power.

[0047] (Other Embodiments) Note that the embodiments and modifications described above are merely examples, and the scope of the technical idea of the present disclosure is not limited to the above-described configurations. Other aspects conceivable within the scope of the technical idea of the present disclosure are also included in the scope of the present disclosure.

[0048] The processing steps shown in the flowchart do not necessarily have to be executed in the order shown in the figure. The processing steps may be executed in an order different from the order shown in the figure, or two or more processing steps may be executed in parallel. Also, some of the processing steps may be deleted, and further processing steps may be added.

[0049] The functions of the above-described respective devices, for example, the direction estimation device 10, the wireless communication device 20, and the direction estimation device 22 may be realized by any one of software, hardware, and a combination of software and hardware. The program code (instructions) constituting the software may be stored, for example, in a computer-readable recording medium inside or outside each device, read into the memory at the time of execution, and executed by the processor. Also, a computer-readable non-transitory recording medium storing the program code may be provided.

[0050] For example, FIG. 6 shows an example of a combination of software and hardware that realizes the functions of the direction estimation device 10 described in the first embodiment. The information processing device 40 includes a non-transitory recording medium 41, a memory 42, and a processor 43. The non-transitory recording medium 41, the memory 42, and the processor 43 are connected to each other via an internal bus 44.

[0051] The non-transitory recording medium 41 stores program code for realizing the functional blocks of the direction estimation device 10, specifically, the acquisition unit 11, the calculation unit 12, and the estimation unit 13. The program code for realizing the functional blocks of the direction estimation device 10 is read into the memory 42. By the processor 43 executing the program code read into the memory 42, the processing of the functional blocks of the direction estimation device 10 is executed. Similarly, for the wireless communication device 20 and the direction estimation device 22, they may be realized by a combination of a non-transitory recording medium, a memory, and a processor.

[0052] As described above, the present disclosure has been described with reference to the embodiments, but the present disclosure is not limited to the above-described embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. And each embodiment can be combined with other embodiments as appropriate.

[0053] The drawings are merely examples for explaining one or more embodiments. Each drawing is not associated with only one specific embodiment, but may be associated with one or more other embodiments. As can be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with the features or steps shown in one or more other drawings, for example, to create embodiments that are not explicitly illustrated or described. Not all of the features or steps shown in any one drawing for explaining exemplary embodiments are necessarily essential, and some features or steps may be omitted. The order of the steps described in any drawing may be changed as appropriate.

[0054] Some or all of the above embodiments may be described as follows, but are not limited thereto.

[0055] [Appendix 1] An acquisition unit that acquires information regarding the received power of a plurality of beams received via a propagation path; A calculation unit that calculates the similarity between the received power and the beam gain of the plurality of beams for a plurality of directions; An estimation unit that estimates the propagation direction of radio waves in the propagation path based on the similarity; A direction estimation device comprising the above.

[0056] [Appendix 2] The information regarding the received power of the plurality of beams is at least one of reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), and signal to interference plus noise ratio (SINR); The direction estimation device according to Appendix 1.

[0057] [Appendix 3] The acquisition unit or the calculation unit substitutes a predetermined value for the received power corresponding to a beam for which information regarding the received power is not acquired. The direction estimation device according to Appendix 1 or 2.

[0058] [Appendix 4] The similarity is the cosine similarity between the received power of the plurality of beams and the beam gain. The direction estimation device according to any one of Appendices 1 to 3.

[0059] [Appendix 5] The similarity is calculated based on the difference between the ratio of the received power of two beams included in the plurality of beams and the ratio of the beam gains. The direction estimation device according to any one of Appendices 1 to 3.

[0060] [Appendix 6] The calculation unit limits the plurality of directions based on at least one of the position, orientation, and directivity of the antennas used for transmitting the plurality of beams. The direction estimation device according to any one of Appendices 1 to 5.

[0061] [Appendix 7] The estimation unit estimates the direction in which the similarity is maximum as the propagation direction of the radio wave. The direction estimation device according to any one of Appendices 1 to 6.

[0062] [Appendix 8] The estimation unit estimates, as the propagation direction of the radio wave, a value obtained by weighted averaging the plurality of directions with the similarity. The direction estimation device according to any one of Appendices 1 to 6.

[0063] [Appendix 9] The direction estimation device according to any one of Appendices 1 to 8, and A generating unit that generates a beamforming weight based on the propagation direction of the radio wave, A wireless communication device comprising the same.

[0064] [Appendix 10] Obtain information regarding the received power of a plurality of beams received via a propagation path, Calculate the similarity between the received power and the beam gain of the plurality of beams for a plurality of directions, A direction estimation method including estimating the propagation direction of radio waves in the propagation path based on the similarity.

[0065] [Appendix 11] Obtain information regarding the received power of a plurality of beams received via a propagation path, Calculate the similarity between the received power and the beam gain of the plurality of beams for a plurality of directions, A program for causing a computer to execute a process including estimating the propagation direction of radio waves in the propagation path based on the similarity.

[0066] Some or all of the elements (e.g., configurations and functions) described in Appendices 2 to 8 that are subordinate to Appendix 1 may be subordinate to Appendices 10 and 11 in the same subordinate relationship as Appendices 2 to 8. Some or all of the elements described in any appendix may be applied to various hardware, software, recording means for recording software, systems, and methods.

Explanation of Reference Numerals

[0067] 1: Wireless communication system 10: Direction estimation device 11: Acquisition unit 12: Calculation unit 13: Estimation unit 20: Wireless communication device 21: Received signal processing unit 22: Direction estimation device 23: Beamforming weight generation unit 24: Transmitted signal processing unit 40: Information processing device 41: Non-volatile recording medium 42: Memory 43: Processor

Claims

1. An acquisition unit that acquires information regarding the reception power of a plurality of beams received via a propagation path; A calculation unit that calculates the similarity between the reception power and the beam gain of the plurality of beams for a plurality of directions; An estimation unit that estimates the propagation direction of radio waves in the propagation path based on the similarity; A direction estimation device comprising the above.

2. The information regarding the reception power of the plurality of beams is At least one of reference signal reception power (RSRP: Reference Signal Received Power), reference signal reception quality (RSRQ: Reference Signal Received Quality), received signal strength (RSSI: Received Signal Strength Indicator), and signal-to-interference-plus-noise ratio (SINR: Signal to Interference plus Noise Ratio), The direction estimation device according to Claim 1.

3. The acquisition unit or the calculation unit Substitutes a predetermined value into the reception power corresponding to a beam for which information regarding the reception power has not been acquired. The direction estimation device according to Claim 1 or 2.

4. The similarity is The cosine similarity between the reception power and the beam gain of the plurality of beams. The direction estimation device according to Claim 1 or 2.

5. The similarity is Calculated based on the difference between the ratio of the reception power of two beams included in the plurality of beams and the ratio of the beam gains. The direction estimation device according to Claim 1 or 2.

6. The calculation unit Limits the plurality of directions based on at least one of the position, orientation, and directivity of the antennas used for transmitting the plurality of beams. The direction estimation device according to Claim 1 or 2.

7. The estimation unit Estimates the direction in which the similarity is maximized as the propagation direction of the radio waves. The direction estimation device according to Claim 1 or 2.

8. The direction estimation device according to Claim 1 or 2, and A generation unit that generates a beamforming weight based on the propagation direction of the radio waves. A wireless communication device comprising the above.

9. Acquire information regarding the reception power of a plurality of beams received via a propagation path, Calculate the similarity between the reception power and the beam gain of the plurality of beams for a plurality of directions, A direction estimation method including estimating the propagation direction of radio waves in the propagation path based on the similarity.

10. Obtain information regarding the received power of a plurality of beams received via a propagation path, calculate the similarity between the received power and the beam gain of the plurality of beams for a plurality of directions, A program for causing a computer to execute a process including estimating the propagation direction of radio waves in the propagation path based on the similarity.

Images