Wireless communication device, communication method, and program

Abstract

To provide a wireless communication device capable of suppressing the influence of high-speed fluctuations in reception level on radio wave tracking performance more than ever before.SOLUTION: A wireless communication device includes a beam control unit that controls the direction of multiple receiving beams of a phased array antenna, and a receiving level detection unit that detects the receiving level of each of the multiple receiving beams, and the beam control unit determines the direction of the multiple receiving beams on the basis of the receiving levels of each of the multiple receiving beams, which are detected in parallel over time by the receiving level detection unit.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] For vehicle stations for satellite communication, etc., in order to capture and track a counterpart station such as a satellite, while swinging the antenna at a minute angle, the reception level is monitored, and the direction in which the reception level becomes the largest is detected, and the antenna is controlled in that direction using conical scan (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional conical scan, there is a problem that when high-speed reception level fluctuations occur due to fading, vehicle shaking, etc. while swinging the antenna at a minute angle, it may affect the radio wave tracking performance.

[0005] The present invention has been made in view of such circumstances, and provides a wireless communication device, a communication method, and a program capable of suppressing the influence of high-speed reception level fluctuations on radio wave tracking performance more than before.

Means for Solving the Problems

[0006] The present invention has been made to solve the above-described problems, and one aspect of the present invention is a beam control unit that controls the directions of a plurality of reception beams of a phased array antenna, and a reception level detection unit that detects the reception level in each of the plurality of reception beams. The beam control unit determines the directions of the plurality of reception beams based on the reception levels in each of the plurality of reception beams, which are a plurality of the reception levels detected in parallel in time by the reception level detection unit, and is a wireless communication device.

[0007] Another aspect of the present invention is the above-described wireless communication device, wherein the directions of the plurality of reception beams are directions arranged at equal intervals around a rotation axis.

[0008] Another aspect of the present invention is the above-described wireless communication device, wherein the beam control unit rotates the plurality of reception beams around the rotation axis to perform conical scanning.

[0009] Another aspect of the present invention is the above-described wireless communication device, which includes a reception signal synthesis unit that synthesizes reception signals received using each of the plurality of reception beams.

[0010] Another aspect of the present invention is the above-described wireless communication device, wherein the reception signal synthesis unit selects one of the reception signals received using each of the plurality of reception beams based on the reception levels in each of the plurality of reception beams acquired by the reception level detection unit, and uses it as the synthesized signal.

[0011] Another aspect of the present invention is a communication method, which includes a first step of controlling the directions of a plurality of reception beams of a phased array antenna, and a second step of detecting the reception level in each of the plurality of reception beams. In the first step, the directions of the plurality of reception beams are determined based on the reception levels in each of the plurality of reception beams, which are a plurality of the reception levels detected in parallel in time by the first step.

[0012] Another aspect of the present invention is a program for causing a computer to function as a beam control unit that controls the directions of a plurality of reception beams of a phased array antenna, wherein the beam control unit determines the directions of the plurality of reception beams based on reception levels in each of the plurality of reception beams, the plurality of reception levels being detected in parallel in time.

Advantages of the Invention

[0013] According to this invention, a wireless communication device, a communication method, and a program can suppress the influence on radio wave tracking performance due to rapid reception level fluctuations more than in the prior art.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram showing the configuration of a wireless communication device 10 according to an embodiment of this invention. The wireless communication device 10 is, for example, an in-vehicle station or a ground station for satellite communication, but may be other wireless communication devices. As shown in FIG. 1, the wireless communication device 10 includes a phased array antenna 11, a beam generation unit 12, reception level detection units 13a and 13b, a beam control unit 14, a reception signal combining unit 15, and a data reception unit 16.

[0016] The phased array antenna 11 is a phased array antenna in which a plurality of antenna elements are arranged in a two-dimensional direction. In FIG. 1, eight antenna elements are shown, but the number of antenna elements is not eight and may be other numbers such as 256 or 1024. The beam generation unit 12 branches the received signal of each antenna element of the phased array antenna 11 into two, one for the first received beam and the other for the second received beam, and performs amplification and phase rotation for each branch. The beam generation unit 12 synthesizes the received signals that have been amplified and phase-rotated in the branch for the first received beam of each antenna element. Also, the beam generation unit 12 synthesizes the received signals that have been amplified and phase-rotated in the branch for the second received beam of each antenna element. In this way, the beam generation unit 12 generates the received signal of the first received beam and the received signal of the second received beam by synthesizing each of the branches for the first received beam and the second received beam. For example, a beamforming IC such as F6121 of RENESAS (registered trademark) may be used for the beam generation unit 12.

[0017] The reception level detection unit 13a detects the reception level of the received signal of the first received beam synthesized by the beam generation unit 12. The reception level detection unit 13b detects the reception level of the received signal of the second received beam synthesized by the beam generation unit 12. The reception level detection unit 13a and the reception level detection unit 13b may constitute one reception level detection unit 13.

[0018] The beam control unit 14 controls the directions of the first reception beam and the second reception beam of the phased array antenna 11. More specifically, the beam control unit 14 determines the directions of the first reception beam and the second reception beam based on the reception levels in each of the first reception beam and the second reception beam, that is, a plurality of reception levels (the reception level of the first reception beam and the reception level of the second reception beam) detected in parallel in time by the reception level detection units 13a and 13b. The beam control unit 14 determines the gain values and phase values of amplification and phase rotation corresponding to the determined directions for each of the first reception beam and the second reception beam of each antenna element, and sets the determined gain values and phase values in the beam generation unit 12.

[0019] Note that the directions of the first and second reception beams may be directions arranged every 180 degrees around the rotation axis. Further, the beam control unit 14 may rotate the first reception beam and the second reception beam around the rotation axis to perform conical scanning. In that case, the beam control unit 14 may determine the rotation axis (the direction of the other party) based on a plurality of reception levels detected in parallel in time by the reception level detection units 13a and 13b. The timing at which the beam control unit 14 determines the rotation axis may be each time the first and second reception beams are rotated around the rotation axis and the reception levels of the first and second reception beams are detected by 180 degrees each (a total of 360 degrees), or may be each time the reception levels of the first and second reception beams are detected.

[0020] The reception signal combining unit 15 combines the reception signals received using each of the plurality of reception beams. Note that the reception signal combining unit 15 may select one of the reception signals received using each of the first and second reception beams based on the reception levels in each of the first and second reception beams detected by the reception level detection units 13a and 13b, and use it as the combined signal.

[0021] Note that the reception signal combining unit 15 may be notified by the beam control unit 14 as to which reception signal to select. That is, the beam control unit 14 may select one of the reception signals received using each of the first and second reception beams based on the reception levels in the first and second reception beams detected by the reception level detection units 13a and 13b, and notify the selection result to the reception signal combining unit 15. The beam control unit 14 may select the reception signal with the higher reception level among the reception signals received using each of the first and second reception beams.

[0022] Alternatively, the reception signal combining unit 15 may combine reception signals by adding together the reception signals received using each of a plurality of reception beams. In this case, the beam control unit 14 does not need to select and notify a reception signal.

[0023] FIG. 2 is a schematic diagram for explaining reception beams of conical scanning in the present embodiment. The first reception beam B1 and the second reception beam B2 of the phased array antenna 11 are directions arranged at intervals of 180 degrees around the rotation axis SD, which is the direction of the counterpart station, with a swing width θ. The beam control unit 14 rotates the first reception beam B1 and the second reception beam B2 by φ around the rotation axis. The beam control unit 14 rotates the first reception beam B1 and the second reception beam B2 N times by φ with (N + 1)φ = 180 degrees, and acquires the reception levels at each position from the reception level detection units 13a and 13b. The beam control unit 14 uses, for the next conical scanning, a rotation axis shifted by a predetermined angle toward the larger reception level at the position where the difference in reception levels between the first reception beam B1 and the second reception beam B2 is the largest.

[0024] FIG. 3 is a flowchart for explaining an operation example of the wireless communication device 10 in the present embodiment. First, the beam control unit 14 sets the rotation axis to an initial value (step Sa1). The beam control unit 14 may calculate the direction of the counterpart station based on the position of the wireless communication device 10 detected by GPS (Global Positioning System) or the like, and use the direction of the counterpart station as the initial value of the rotation axis, or may use a predetermined axis as the initial value of the rotation axis.

[0025] Next, based on the rotation axis, the beam control unit 14 determines the directions of a plurality of received beams (the first received beam and the second received beam) (step Sa2). For example, the beam control unit 14 sets the direction obtained by shifting a predetermined amplitude in a predetermined direction (such as the direction of gravity) from the rotation axis as the direction of the first received beam, and sets the direction obtained by rotating the direction of the first received beam by 180 degrees around the rotation axis as the direction of the second received beam.

[0026] Next, the beam control unit 14 acquires the reception levels of the plurality of received beams detected by each of the reception level detection units 13a and 13b (step Sa3). The reception levels of the plurality of received beams are detected temporally in parallel with each other.

[0027] Next, the beam control unit 14 selects a received beam based on the reception levels acquired in step Sa3 and notifies the received signal combining unit 15. The received signal combining unit 15 selects one of the received signals from among the plurality of received signals according to the notification, and the data reception unit 16 demodulates the received signal selected by the received signal combining unit 15 to perform data reception (step Sa4).

[0028] Next, the wireless communication device 10 repeats steps Sa6 to Sa8 N times (steps Sa5 and Sa9). Here, N may be a number such that when φ described later is multiplied by N + 1, it becomes 180 degrees (the interval between the directions of the received beams). φ may be a predetermined number or may be variable according to the reception level.

[0029] In step Sa6, the beam control unit 14 rotates the direction of each of the plurality of received beams by φ around the rotation axis. In step Sa7, the beam control unit 14 acquires the reception levels of the plurality of received beams detected by each of the reception level detection units 13a and 13b. The reception levels of the plurality of received beams are detected temporally in parallel with each other.

[0030] In step Sa8, the beam control unit 14 selects a reception beam based on the reception level acquired in step Sa7 and notifies the reception signal combining unit 15. Further, in accordance with this notification, the reception signal combining unit 15 selects one reception signal from among the plurality of reception beams, and the data reception unit 16 demodulates the reception signal selected by the reception signal combining unit 15 to perform data reception.

[0031] After N repetitions from step Sa6 to Sa8, the beam control unit 14 changes the rotation axis based on the reception level (step Sa10). At this time, the beam control unit 14 compares the reception levels of the plurality of reception beams in each of step Sa4 and the N times of step Sa7, and changes the rotation axis. For example, the beam control unit 14 calculates the difference in the reception levels of the plurality of reception beams in each of step Sa4 and the N times of step Sa7, and shifts the rotation axis in the direction of the reception beam with the higher reception level among the plurality of reception beams in the step where the difference is the largest. At this time, the angle by which the rotation axis is shifted may be a predetermined value, or may be determined based on the difference in reception level, such as becoming larger as the difference in reception level is larger.

[0032] Since the reception levels of the plurality of reception beams in each of step Sa4 and the N times of step Sa7 are detected temporally in parallel with each other, the comparison of the reception levels of the plurality of reception beams in each of step Sa4 and the N times of step Sa7 is not affected by fast reception level fluctuations due to fading or the like.

[0033] Next, when the wireless communication device 10 terminates communication (step Sa11 - Y), it ends the process, and when it continues communication (step Sa11 - N), it returns to step Sa2.

[0034] In the above-described embodiment, an example in which the beam control unit 14 controls the directions of two received beams has been given. However, the beam control unit 14 may control the directions of three or more received beams. When the beam control unit 14 controls the directions of three or more received beams, based on the reception levels in each of the three or more received beams, which are three or more reception levels detected in parallel in time by the reception level detection unit 13, the directions of the three or more received beams are determined. Also, the directions of the three or more received beams may be directions arranged at equal intervals around the rotation axis. Further, the beam control unit 14 may rotate the three or more received beams around the rotation axis to perform conical scanning.

[0035] <Modification Example> FIG. 4 is a schematic diagram for explaining the received beams of conical scanning in a modification example of the present embodiment. FIG. 4 shows an example in which the beam control unit 14 controls the directions B41, B42, and B43 of three received beams of the phased array antenna 11. In this case, the directions of the three received beams are directions arranged at 120-degree intervals around the rotation axis SD. When there are three received beams, in step Sa10 of FIG. 3, the beam control unit 14 calculates the difference between the maximum and minimum of the reception levels of the three received beams in each of step Sa4 and N times of step Sa7, and may shift the rotation axis in the direction of the received beam with the maximum reception level among the plurality of received beams in the step where the difference is the largest.

[0036] Further, the present invention may also be the following embodiments. (1) One embodiment is a wireless communication device including a beam control unit that controls the directions of a plurality of received beams of a phased array antenna, and a reception level detection unit that detects the reception level in each of the plurality of received beams, wherein the beam control unit determines the directions of the plurality of received beams based on the reception levels in each of the plurality of received beams, which are a plurality of the reception levels detected in parallel in time by the reception level detection unit.

[0037] Thus, since the reception levels of the plurality of reception beams are detected temporally in parallel with each other, the wireless communication device can suppress the influence on the radio wave tracking performance of high-speed reception level fluctuations more than before.

[0038] (2) Also, another embodiment is the wireless communication device according to (1), wherein the directions of the plurality of reception beams are directions arranged at equal intervals around the rotation axis.

[0039] Thereby, the wireless communication device can determine the direction of the reception beam using the reception levels of the reception beams arranged evenly.

[0040] (3) Also, another embodiment is the wireless communication device according to (1) or (2), wherein the beam control unit rotates the plurality of reception beams around the rotation axis to perform conical scanning.

[0041] Thereby, the wireless communication device can perform conical scanning without being affected by high-speed reception level fluctuations due to fading or the like.

[0042] (4) Also, another embodiment is the wireless communication device according to any one of (1) to (3), further comprising a reception signal combining unit that combines the reception signals received using each of the plurality of reception beams.

[0043] Thereby, the wireless communication device can obtain the effect of reception diversity.

[0044] (5) Also, another embodiment is the wireless communication device according to any one of (1) to (4), wherein the reception signal combining unit selects one of the reception signals received using each of the plurality of reception beams based on the reception level of each of the plurality of reception beams acquired by the reception level detection unit, and uses it as the combined signal.

[0045] Thereby, the wireless communication device can use the reception signal of the reception beam corresponding to the reception level among the plurality of reception beams.

[0046] (6) Also, another embodiment is a communication method, which includes a first step of controlling the directions of a plurality of receiving beams of a phased array antenna, and a second step of detecting the reception level in each of the plurality of receiving beams. In the first step, based on the reception levels in each of the plurality of receiving beams, which are a plurality of the reception levels detected temporally in parallel by the first step, the directions of the plurality of receiving beams are determined.

[0047] (7) Also, another embodiment is a program for causing a computer to function as a beam control unit that controls the directions of a plurality of receiving beams of a phased array antenna. The beam control unit determines the directions of the plurality of receiving beams based on the reception levels in each of the plurality of receiving beams, which are a plurality of the reception levels detected temporally in parallel.

[0048] Further, a program for realizing at least some functions of the wireless communication device 10 in FIG. 1 may be recorded on a computer-readable recording medium, and the wireless communication device 10 may be realized by causing the computer system to read and execute the program recorded on this recording medium. Here, the "computer system" is assumed to include hardware such as an OS and peripheral devices.

[0049] In addition, the "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, etc., and storage devices such as hard disks built into computer systems. Furthermore, the "computer-readable recording medium" also includes those that dynamically hold a program for a short period of time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and those that hold a program for a certain period of time, like the volatile memory inside a computer system that serves as a server or a client in that case. Also, the above program may be for realizing a part of the aforementioned functions, and furthermore, it may be able to realize the aforementioned functions in combination with a program already recorded in the computer system.

[0050] In addition, each functional block of the wireless communication device 10 in FIG. 1 described above may be individually chip-sized, or may be partially or entirely integrated and chip-sized. Also, the method of integrating into a circuit is not limited to LSI, and it may be realized by a dedicated circuit or a general-purpose processor. Either hybrid or monolithic may be used. A part may realize functions by hardware and a part by software.

[0051] As described above, the embodiments of this invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of this invention are also included.

Explanation of Reference Numerals

[0052] 10 Wireless communication device 11 Phased array antenna 12 Beam generation unit 13a, 13b Reception level detection unit 14 Beam control unit 15 Received signal synthesis unit 16 Data reception unit

Claims

1. A beam control unit that controls the directions of a plurality of reception beams of a phased array antenna, and a reception level detection unit that detects the reception level in each of the plurality of reception beams are provided, wherein the beam control unit determines the directions of the plurality of reception beams based on the reception levels in each of the plurality of reception beams, the plurality of reception levels detected in parallel in time by the reception level detection unit. A wireless communication device.

2. The directions of the plurality of reception beams are directions arranged at equal intervals around a rotation axis. The wireless communication device according to Claim 1.

3. The beam control unit rotates the plurality of reception beams around the rotation axis to perform conical scanning. The wireless communication device according to Claim 2.

4. A reception signal combining unit that combines reception signals received using each of the plurality of reception beams is provided. The wireless communication device according to any one of Claims 1 to 3.

5. Based on the reception levels in each of the plurality of reception beams acquired by the reception level detection unit, the reception signal combining unit selects one of the reception signals received using each of the plurality of reception beams and uses it as a combined signal. The wireless communication device according to Claim 4.

6. A communication method comprising: a first step of controlling the directions of a plurality of reception beams of a phased array antenna; and a second step of detecting the reception level in each of the plurality of reception beams. In the first step, based on the reception levels in each of the plurality of reception beams, the plurality of reception levels detected in parallel in time by the first step, the directions of the plurality of reception beams are determined. A communication method.

7. A program for causing a computer to function as a beam control unit that controls the directions of a plurality of reception beams of a phased array antenna, wherein the beam control unit determines the directions of the plurality of reception beams based on the reception levels in each of the plurality of reception beams, the plurality of reception levels detected in parallel in time. A program. ​ ​

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