BEAM SETTING METHOD, BEAM SETTING DEVICE, AND PROGRAM

Abstract

Provided is a beam setting method comprising: a communication method prediction step for predicting a communication method to be performed on the basis of whether or not there is a line of sight between a first wireless station device and a second wireless station device; a first beam number setting step for, when it has been predicted in the communication method prediction step that communication will be performed by a communication method using reflection waves, setting to a first constant the number of beams transmitted by a beam sweep that sequentially transmits signals using formable beams in a time division manner; and a second beam number setting step for, when it has been predicted in the communication method prediction step that communication will be performed by a communication method using line-of-sight waves, setting the number of beams transmitted by the beam sweep to a second constant which is smaller than the first constant.

Description

[Technical field]

[0001] The present invention relates to a beam setting method, a beam setting device, and a program. [Background technology]

[0002] Examples of wireless communication using millimeter waves and quasi-millimeter waves, which are classified as high frequency bands, include 3GPP (3rd Generation Partnership Project) 5G (5th Generation) NR (New Radio) and IEEE802.11ad. These wireless communication technologies have advantages such as being able to secure a wider bandwidth than conventional microwave bands, and having a high degree of directivity and less interference with other communications. For this reason, they are being put into practical use as a means of realizing high-capacity wireless communication (for example, Non-Patent Document 1).

[0003] The amount of attenuation over a wireless propagation path increases with frequency. Therefore, in millimeter wave communications, a wireless station device typically forms a directional beam (beamforming) toward a wireless station device with which it is communicating to transmit a signal. Similarly, a wireless station device typically forms a directional beam to receive a signal.

[0004] A wireless station device selects a beam that maximizes the received power at a wireless station device located opposite from among the directional beams that can be formed. In IEEE802.11ad, for example, beam selection is performed by a procedure called SLS (Sector Level Sweep) (see Non-Patent Document 2).

[0005] FIG. 4 is a conceptual diagram of a communication system 9 that selects a beam. The communication system 9 includes a first wireless station device 91 and a second wireless station device 92. The first wireless station device 91 is a side (initiator) that transmits communication, and the second wireless station device 92 is a side (responder) that receives communication from the first wireless station device 91. The first wireless station device 91 sequentially transmits signals using beams that can be formed in a time-division manner. The sequential transmission of signals performed by the initiator is called beam sweep. The beams that the first wireless station device 91 can form are linked to IDs in advance and shared with the second wireless station device 92. The second wireless station device 92 receives the signal transmitted from the first wireless station device 91 using a beam with the maximum beam width and measures the received power. After that, the first wireless station device 91 and the second wireless station device 92 share the ID of the beam with the maximum received power, and the first wireless station device 91 selects a beam corresponding to the shared ID.

[0006] Similarly, in 5G NR, multiple signal blocks called SS / PBCH (Synchronization Signal / Physical Broadcast CHannel) are transmitted sequentially in a time-division manner for each beam of the wireless base station device, and the beam with the highest received power from the opposite wireless station device is selected.

[0007] The second radio station device 92 may perform a beam sweep on the first radio station device 91 to select a beam. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Takinami et al., "Standardization Trends and Elemental Technologies of Millimeter-Wave Wireless LAN Systems," IEICE Communications Society Magazine, Fall 2016, No. 38, pp. 100-106 [Non-Patent Document 2] IEEE, “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 3: Enhancements for Very High Throughput in the 60 GHz Band” (IEEE Std 802.11ad-2012), 2012 / 12 / 28 [Non-Patent Document 3] T. Nishio, R. Arai, K. Yamamoto and M. Morikura, "Proactive traffic control based on human blockage prediction using RGBD cameras for millimeter-wave communications," 2015 12th Annual IEEE Consumer Communications and Networking Conference (CCNC), 2015, pp. 152-153, doi: 10.1109 / CCNC.2015.7157963. Summary of the Invention [Problem to be solved by the invention]

[0009] However, as the communication frequency increases, the number of antenna elements in the radio station device increases and the width of the directional beam narrows. In the beam selection method using the above-mentioned SLS or SS / PBCH, the processing time may increase because the beam is selected by time division and brute force. The present invention aims to reduce processing time when selecting a beam. [Means for solving the problem]

[0010] One aspect of the present invention is a beam setting method having a communication method prediction step of predicting a communication method to be performed based on whether or not there is line of sight between a first radio station device and a second radio station device; a first beam number setting step of setting the number of beams to be transmitted by beam sweep, which sequentially transmits signals using formable beams in a time-division manner, to a first constant if the communication method prediction step predicts that communication will be performed by a communication method that uses reflected waves; and a second beam number setting step of setting the number of beams to be transmitted by beam sweep to a second constant smaller than the first constant if the communication method prediction step predicts that communication will be performed by a communication method that uses line-of-sight waves.

[0011] One aspect of the present invention is a beam setting device comprising a communication method prediction unit that predicts a communication method to be performed based on whether there is line of sight between a first radio station device and a second radio station device, a first beam number setting unit that, when the communication method prediction unit predicts that communication will be performed using a communication method that uses reflected waves, sets to a first constant the number of beams to be transmitted by beam sweep, which sequentially transmits signals using formable beams in a time-division manner, and a second beam number setting unit that, when the communication method prediction unit predicts that communication will be performed using a communication method that uses line-of-sight waves, sets to a second constant that is smaller than the first constant the number of beams to be transmitted by beam sweep.

[0012] One aspect of the present invention is a program for causing a computer to execute the above beam setting method. Effect of the Invention

[0013] The number of beams can be set to accommodate both communications using line-of-sight waves and communications using reflected waves. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram illustrating an example of the configuration of a first wireless station device 11. [Figure 2A] 2 is a diagram showing beams transmitted by a first radio station device 11. FIG. [Figure 2B] 2 is a diagram showing beams transmitted by a first radio station device 11. FIG. [Diagram 3] 5 is a flowchart showing a beam sweep method performed by the first radio station device 11. [Figure 4] FIG. 1 is a conceptual diagram of a communication system 9 that performs beam selection. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] 1 is a diagram showing an example of the configuration of a first wireless station device 11. The first wireless station device 11 includes an antenna 110, a wireless communication unit 111, a data processing unit 112, a beam sweep unit 113, a beam mode setting unit 114, a communication method prediction unit 115, and a used beam determination unit 116. The wireless communication unit 111 transmits data input from the data processing unit 112 via the antenna 110. In addition, the wireless communication unit 111 outputs data received by the antenna 110 to the data processing unit 112.

[0016] The data processing unit 112 outputs data input from an upper network or its interface (not shown) to the wireless communication unit 111. The data processing unit 112 outputs data input from the wireless communication unit 111 to the upper network or its interface.

[0017] The beam sweep unit 113 controls the wireless communication unit 111 to periodically perform beam sweeping. The beam mode setting unit 114 sets the number of beams in the beam sweep performed by the beam sweep unit 113 based on the prediction result by the communication method prediction unit 115.

[0018] The number of beams when the wireless communication unit 111 performs beam sweeping is set as, for example, a first constant or a second constant. The first constant and the second constant are positive integer values, and the first constant is a value greater than the second constant. FIGS. 2A and 2B are diagrams showing beams transmitted by the first wireless station device 11. The number of beams beam swept by the first wireless station device 11 shown in FIG. 2A is a first constant, for example, nine. The first constant may be the number of all beams that the wireless communication unit can take. The number of beams beam swept by the first wireless station device 11 shown in FIG. 2B is a second constant, for example, five. A beam sweep in which the number of beams is the first constant is called a first sweep mode, and a beam sweep in which the number of beams is the second constant is called a second sweep mode.

[0019] In the first sweep mode and the second sweep mode, which beams the first radio station device 11 may sweep may vary depending on the position of the opposite second radio station device 12 and the surrounding propagation environment. Also, in Figures 2A and 2B, the number of beams in the first sweep mode is 9 and the number of beams in the second sweep mode is 5, but this is not limited to this.

[0020] In the first sweep mode shown in FIG. 2A, beam sweep is performed with nine beams from beam #1 to #9, whereas in the second sweep mode shown in FIG. 2B, beam sweep is performed with five beams from beam #3 to #7. In the high frequency band, the directivity of radio waves is high, and there is a high possibility that communication will be performed using line-of-sight waves. In other words, if the beam selected at a certain point in time is beam #5, the next beam selected is likely to be the nearby beams #4 and #6, and beams #1 and #9 are unlikely to be selected. Therefore, beams #1 and #9 are often appropriately selected without beam sweep. Therefore, in the case of communication using line-of-sight waves, the second sweep mode has fewer beams to sweep than the first sweep mode, and it is possible to select an appropriate beam while reducing processing time.

[0021] On the other hand, the first sweep mode is effective when the first radio station device 11 communicates using reflected waves. For example, when there is an obstruction between the first radio station device 11 and the second radio station device 12, the first radio station device 11 may communicate with the second radio station device 12 by using beam #1 or #9 and reflecting it off the obstruction.

[0022] The communication method prediction unit 115 predicts which of the communication methods using reflected waves and line-of-sight waves will be used for communication. The communication method prediction unit 115 predicts the communication method to be used based on, for example, the visibility of the surrounding environment. The communication method prediction unit 115 predicts the communication method to be used based on the visibility of communication between the first radio station device 11 and the second radio station device 12, which is the communication partner. When an obstruction is detected using, for example, an RGB-D camera, the communication method prediction unit 115 predicts that the communication to be used will be a communication method using reflected waves (see Non-Patent Document 3 for a method of detecting an obstruction). When, for example, the directional difference between the beam selected by the beam sweep unit 113 and the beam selected before selecting the beam is equal to or less than a certain value, the communication method prediction unit 115 predicts that the communication to be used will be a communication method using line-of-sight waves.

[0023] The beam-to-beam determination unit 116 determines the beam to be used for communication. The beam-to-beam determination unit 116 determines the beam to be used for communication based on data transmitted by the second radio station device 12. The data transmitted by the second radio station device 12 is, for example, data on the reception strength of each beam when the first radio station device 11 performs beam sweep. At this time, the beam-to-be used determination unit 116 determines the beam with the highest reception strength to be the beam to be used for communication. The data transmitted by the second radio station device 12 may be an ID corresponding to the beam with the highest reception strength among the beams when the first radio station device 11 performs beam sweep. At this time, the beam-to-be used determination unit 116 determines the beam corresponding to the ID to be the beam to be used for communication.

[0024] FIG. 3 is a flowchart showing a method of beam sweep performed by the first wireless station device 11. First, the communication method prediction unit 115 predicts the method of communication to be performed (step S1). If there is no line of sight (step S2: NO), the beam mode setting unit 114 sets the sweep mode to the first sweep mode (step S31). If there is line of sight (step S2: YES), the beam mode setting unit 114 sets the sweep mode to the second sweep mode (step S32). Note that if the sweep mode has already been set to the first sweep mode and the communication method prediction unit 115 determines that there is no line of sight, the beam mode setting unit 114 does not set the sweep mode to the first sweep mode but maintains the existing setting. Also, if the sweep mode has already been set to the second sweep mode and the communication method prediction unit 115 determines that there is line of sight, the beam mode setting unit 114 does not set the sweep mode to the second sweep mode but maintains the existing setting.

[0025] Thereafter, the beam sweep unit 113 performs beam sweep according to the set sweep mode (step S4). The second radio station device 12 receives the beam transmitted from the first radio station device 11 (step S5) and transmits data on the reception strength to the first radio station device 11 (step S6). Thereafter, the use beam determination unit 116 determines the beam to be used for communication based on the data on the reception strength (step S7).

[0026] With the above configuration, when the first radio station device 11 predicts that the communication method to be performed is communication using line-of-sight waves, it is highly likely that a beam close to the beam being used will be selected, so it performs beam sweep in the second sweep mode with a smaller number of beams, thereby reducing the processing time required for sweeping. On the other hand, when the first radio station device 11 predicts that the communication method to be performed is communication using reflected waves, it is highly likely that a beam not included in the beams close to the beam being used will be selected, so it performs beam sweep in the first sweep mode with a larger number of beams, thereby more reliably finding a beam suitable for communication. This makes it possible to achieve both transmission efficiency and communication quality.

[0027] While one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included.

[0028] The sweep mode is not limited to the first sweep mode and the second sweep mode. For example, the sweep mode may be three or more, and the number of beams corresponding to each sweep mode may be different. In this case, when the communication method prediction unit 115 predicts that communication will be performed by a communication method using line-of-sight waves, the beam mode setting unit 114 changes the sweep mode being set to a sweep mode having the next smallest number of beams after the number of beams corresponding to the sweep mode being set. When the communication method prediction unit 115 predicts that communication will be performed by a communication method using reflected waves, the beam mode setting unit 114 changes the sweep mode being set to a sweep mode having the next largest number of beams after the number of beams corresponding to the sweep mode being set. This allows the number of beams to be swept to be increased or decreased in stages.

[0029] Although the beam mode setting unit 114 sets the beam mode based on the prediction by the communication method prediction unit 115 when performing the beam sweep, this is not limited to this. For example, the beam mode setting unit 114 may change the setting from the first sweep mode to the second sweep mode when the communication method prediction unit 115 predicts that communication will be performed by a communication method using line-of-sight waves a certain number of times or more up to that point in time.

[0030] A part or all of the first radio station device 11 and the second radio station device 12 in the above-mentioned embodiment may be realized by a computer. In that case, a program for realizing the function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the function. The term "computer system" here includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also include a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in that case. The above-mentioned program may be a program for realizing a part of the above-mentioned function, or may be a program that can realize the above-mentioned function in combination with a program already recorded in the computer system, or may be a program that is realized using a programmable logic device such as an FPGA (Field Programmable Gate Array). [Explanation of symbols]

[0031] 11, 91 first radio station device, 12, 92 second radio station device, 110 antenna, 111 wireless communication unit, 112 data processing unit, 113 beam sweep unit, 114 beam mode setting unit, 115 communication method prediction unit, 116 use beam determination unit

Claims

1. a communication method predicting step of predicting a communication method to be performed based on whether or not there is line of sight between the first wireless station device and the second wireless station device; a first beam number setting step of setting the number of beams to be transmitted by a beam sweep that sequentially transmits signals using formable beams in a time-division manner to a first constant when the communication method prediction step predicts that communication will be performed by a communication method using reflected waves; a second beam number setting step of setting the number of beams transmitted by the beam sweep to a second constant smaller than the first constant when the communication method prediction step predicts that communication will be performed by a communication method using line-of-sight waves; having The first beam number setting step sets the number of beams to be transmitted by the beam sweep when it is predicted that communication will be performed by a communication method using a reflected wave a certain number of times or more to the first constant, The second beam number setting step sets the number of beams transmitted by the beam sweep to the second constant when it is predicted that communication will be performed by a communication method using line-of-sight waves a certain number of times or more. How to set up the beam.

2. a communication method predicting step of predicting a communication method to be performed based on whether or not there is line of sight between the first wireless station device and the second wireless station device; a first beam number setting step for setting the number of beams to be transmitted by a beam sweep that sequentially transmits signals using formable beams in a time-division manner to a number greater than a set number when the communication method prediction step predicts that communication will be performed by a communication method using reflected waves; a second beam number setting step of setting the number of beams transmitted by the beam sweep to a number smaller than a set number when the communication method prediction step predicts that communication will be performed by a communication method using line-of-sight waves; having The first beam number setting step sets the number of beams to be transmitted by the beam sweep to a number greater than a set number when it is predicted that communication will be performed by a communication method using reflected waves a certain number of times or more, The second beam number setting step sets the number of beams transmitted by the beam sweep to a number smaller than the set number when it is predicted that communication will be performed by a communication method using line-of-sight waves a certain number of times or more. How to set up the beam.

3. The communication method prediction step predicts that communication will be performed by a communication method using reflected waves when an obstruction is detected between the first radio station device and the second radio station device. The beam setting method according to claim 1 or 2.

4. The communication method prediction step predicts that communication will be performed by a communication method using line-of-sight waves when a directional difference between a beam determined to be used and a beam used before the determined beam is determined is equal to or less than a certain value. The beam setting method according to any one of claims 1 to 3.

5. a communication method prediction unit that predicts a communication method to be performed based on whether or not there is line of sight between the first wireless station device and the second wireless station device; a first beam number setting unit that sets the number of beams to be transmitted by a beam sweep that sequentially transmits signals using formable beams in a time division manner to a first constant when the communication method prediction unit predicts that communication will be performed by a communication method using reflected waves; a second beam number setting unit that sets the number of beams transmitted by the beam sweep to a second constant smaller than the first constant when the communication method prediction unit predicts that communication will be performed by a communication method using line-of-sight waves; Equipped with The first beam number setting unit sets the number of beams transmitted by the beam sweep to the first constant when it is predicted that communication will be performed by a communication method using reflected waves a certain number of times or more, The second beam number setting unit sets the number of beams transmitted by the beam sweep to the second constant when it is predicted that communication will be performed by a communication method using line-of-sight waves a certain number of times or more. Beam setting device.

6. A program for causing a computer to execute the beam setting method according to any one of claims 1 to 4.

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