Beam controller, wireless communication device, and beam control method

Abstract

To provide a beam controller capable of capturing or tracking a signal from a companion station in a shorter time than before.SOLUTION: A beam controller controls the direction of a receiving beam of an antenna performing a conical scan, and acquires respective receiving levels for multiple receiving beams in a current conical scan, and determines multiple receiving beams in a next conical scan on the basis of a gradient of the receiving levels.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a beam controller, a wireless communication device, and a beam control method. [Background technology]

[0002] Some vehicle-mounted satellite communication stations use conical scanning to capture and track a satellite or other station by monitoring the reception level while swinging the antenna at a slight angle, detecting the direction with the highest reception level, and controlling the antenna in that direction (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-270806 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional conical scanning has the problem that it takes a long time to capture or track the signal from the other station because it monitors the reception levels at a large number of sample points, for example 200 points, and controls the direction of the antenna.

[0005] The present invention has been made in view of the above circumstances, and provides a beam controller, a wireless communication device, and a beam control method that are capable of capturing or tracking a signal from a remote station in a shorter time than conventional methods. [Means for solving the problem]

[0006] The present invention has been made to solve the above-described problems, and one aspect of the present invention is a beam controller that controls the direction of a reception beam of an antenna that performs conical scanning, obtains a reception level in each of a plurality of reception beams in the current conical scanning, and determines a plurality of reception beams in the next conical scanning based on the gradient of the reception level.

[0007] Another aspect of the present invention is the above-described beam controller, wherein a plurality of reception beams in each conical scan are determined based on at least a rotation axis and a swing width from the rotation axis, and the rotation axis of the second conical scan, which is the next scan after the first scan, is determined by moving the rotation axis of the first conical scan in the tracking direction by the amount of movement, and the tracking direction is calculated by synthesizing the gradients between reception beams of the reception levels in each of the plurality of reception beams in the first conical scan.

[0008] Another aspect of the present invention is the above-described beam controller, wherein the smaller the synthesis result of the gradient of the reception level, the smaller the amount of movement.

[0009] Another aspect of the present invention is the above-described beam controller, wherein the swing width in the second conical scan is determined based on the synthesis result of the gradients of the reception levels in each of the plurality of reception beams in the first conical scan.

[0010] Another aspect of the present invention is a wireless communication device including a beam control unit that controls the direction of a reception beam of an antenna that performs conical scanning, the beam control unit obtains a reception level in each of a plurality of reception beams in the current conical scanning, and determines a plurality of reception beams in the next conical scanning based on the gradient of the reception level.

[0011] Another aspect of the present invention is a beam control method for controlling the direction of a receiving beam of an antenna performing a conical scan, the beam control method comprising the steps of acquiring a receiving level for each of multiple receiving beams in the current conical scan, and determining multiple receiving beams in the next conical scan based on a gradient of the receiving levels. Effect of the Invention

[0012] According to the present invention, the beam controller, the wireless communication device, and the beam control method can capture or track the signal of the other station in a shorter time than before. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic block diagram showing a configuration of a wireless communication device 10 according to an embodiment of the present invention. [Diagram 2] 4 is a schematic diagram illustrating a receiving beam of a conical scan in the embodiment. FIG. [Diagram 3] 11 is a schematic diagram for explaining the arrangement of a receiving beam for conical scanning and synthesis of a receiving level gradient in the embodiment. FIG. [Figure 4] 5 is a flowchart showing an example of the operation of the beam controller 15 in the embodiment. [Diagram 5] 11 is a graph showing an example of transition of a reception level at the start of a conical scan in the embodiment. [Figure 6] 1 is a graph showing an example of signal tracking by a conventional conical scan. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic block diagram showing a configuration of a wireless communication device 10 according to an embodiment of the present invention. The wireless communication device 10 is, for example, a vehicle-mounted 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 an antenna 11, a beam generator 12, a data receiver 13, a reception level detector 14, and a beam controller 15 (beam control unit).

[0015] The antenna 11 is a phased array antenna in which a plurality of antenna elements are arranged in a two-dimensional direction. Although eight antenna elements are shown in FIG. 1, the number of antenna elements may be other than eight, such as 256 or 1024. The beam generator 12 amplifies and phase rotates the received signals of each antenna element of the antenna 11, and combines the amplified and phase-rotated received signals. The beam generator 12 generates a receiving beam by this amplification, phase rotation, and combination. For example, a beamforming IC such as F6121 by RENESAS (registered trademark) may be used for the beam generator 12. The data receiver 13 performs reception processing such as demodulation on the received signals combined by the beam generator 12, and acquires data indicated by the received signals.

[0016] The reception level detector 14 detects the reception level of the reception signal combined by the beam generator 12. The beam controller 15 determines the gain and phase values ​​of amplification and phase rotation by the beam generator 12 for each antenna element based on the reception level detected by the reception level detector 14, and sets the determined gain and phase values ​​in the beam generator 12. In this way, the beam controller 15 controls the direction of the reception beam of the antenna 11 performing a conical scan. The beam controller 15 acquires the reception level of each of the multiple reception beams in the current conical scan, and determines the multiple reception beams in the next conical scan based on the gradient of the reception levels.

[0017] The multiple reception beams in each conical scan are determined based on at least the rotation axis and the swing width from the rotation axis. The beam controller 15 may determine the rotation axis of the second conical scan, which is the next to the first, by moving the rotation axis of the first conical scan in the tracking direction by the amount of movement. At this time, the beam controller 15 may calculate the tracking direction by combining the gradients between the reception beams of the reception levels of each of the multiple reception beams in the first conical scan.

[0018] The beam controller 15 may reduce the amount of movement as the combined result of the gradients of the reception levels is smaller. The beam controller 15 may determine the amplitude in the second conical scan based on the combined result of the gradients of the reception levels of the multiple reception beams in the first conical scan.

[0019] Fig. 2 is a schematic diagram for explaining the receiving beam of the conical scan in this embodiment. In Fig. 2, the antenna 11 has antenna elements arranged two-dimensionally on a plane. The receiving beam BR of the conical scan is determined at least by the rotation axis AR and the swing width θ of the conical scan. The receiving beam BR of the conical scan is the generating line of a cone determined by the rotation axis AR and the swing width θ, and may be arranged at every receiving beam interval φ. The wireless communication device 10 in Fig. 1 may include a data transmitter, and transmit data from the antenna 11 with a transmission beam in the direction of the rotation axis AR.

[0020] Fig. 3 is a schematic diagram for explaining the arrangement of receiving beams in a conical scan and the synthesis of receiving level gradients in this embodiment. Fig. 3 is a cross-sectional view in a plane perpendicular to the rotation axis AR in Fig. 2. Receiving beams BR1 to BR4 are arranged at receiving beam intervals φ (90 degrees in Fig. 4) on a circumference with the rotation axis AR as the center and the swing width θ as the radius. In the example of Fig. 3, receiving beams BR1 and BR3 are aligned in the azimuth angle direction, and receiving beams BR2 and BR4 are aligned in the elevation angle direction.

[0021] The beam controller 15 calculates a gradient AZ of the reception level in the azimuth direction from the reception level of the reception beam BR1 and the reception level of the reception beam BR3. For example, the gradient AZ is calculated by ((the reception level of the reception beam BR1)-(the reception level of the reception beam BR3)) / 2Sinθ. Note that Sinθ may be approximated by θ. The beam controller 15 also calculates a gradient EL of the reception level in the elevation direction from the reception level of the reception beam BR2 and the reception level of the reception beam BR4. For example, the gradient EL is calculated by ((the reception level of the reception beam BR2)-(the reception level of the reception beam BR4)) / 2Sinθ. Note that Sinθ may be approximated by θ, as with the gradient AZ.

[0022] Beam controller 15 sets tracking direction TD to the direction of a gradient vector obtained by combining gradients AZ and EL, i.e., a vector (AZ, EL) whose azimuth component is gradient AZ and whose altitude component is gradient EL. In this way, since the tracking direction is determined using the gradient of the reception level, the number of reception beams for acquiring reception levels can be reduced, and the tracking direction can be determined in a shorter time than before.

[0023] 3 shows a case where four reception beams BR1 to BR4 are used, but the number of reception beams may be any number equal to or greater than three. For example, if the number of reception beams is N and a gradient vector consisting of the reception level of the i-th (where 1≦i≦N) reception beam and the gradient of the reception level of the i+1-th (1 when i=N) reception beam in the azimuth angle direction and altitude angle direction is vector Ri, beam controller 15 may set the sum (combination) of vectors Ri for i=1 to N as the tracking direction.

[0024] Furthermore, the beam controller 15 may determine the magnitude of the movement amount TV based on the magnitude of the gradient vector (vector (AZ, EL)). The beam controller 15 may determine the magnitude of the movement amount TV using a relational expression between the magnitude of the gradient vector and the magnitude of the movement amount TV, or may store a table in which the range of the magnitude of the gradient vector and the magnitude of the movement amount TV are associated in advance, and use the table to determine the magnitude of the movement amount TV. The magnitude of the movement amount TV may be the angle at which the rotation axis swings in the tracking direction. For example, the beam controller 15 may make the magnitude of the movement amount TV smaller as the magnitude of the gradient vector becomes smaller. Thereby, when the direction of the other station is close to the rotation axis AR (the rotation axis AR is close to the peak position of the reception level) and the gradient of the reception level is small, the movement amount of the rotation axis becomes small, and the beam controller 15 can stabilize the reception level. Note that the beam controller 15 may be configured to make the magnitude of the movement amount TV smaller as the magnitude of the gradient vector becomes smaller when a predetermined condition is satisfied. This predetermined condition may be that the reception level is equal to or higher than a threshold value, or may be that it has been confirmed that the received signal has been demodulated (decoded) and is a signal of the other station. When the reception level is less than the threshold value or it cannot be confirmed that the received signal is a signal of the other station, the direction of the rotation axis AR may be determined based on the position of the other station or the positional relationship between the own station and the other station.

[0025] FIG. 4 is a flowchart showing an operation example of the beam controller 15 in the present embodiment. First, the beam controller 15 determines the rotation axis and the swing width of the first conical scan (step Sa1). For example, the beam controller 15 may use predetermined values for the rotation axis and the swing width of the first conical scan. Further, the beam controller 15 may estimate the direction of the other station from the position and orientation of the own station, and set the rotation axis of the first conical scan to the direction of the other station.

[0026] Next, the beam controller 15 determines a plurality of reception beams based on the rotation axis and the swing width, and acquires the reception level of each of the plurality of reception beams (step Sa2). Here, the beam controller 15 sets the gain and phase according to the reception beam in the beam generator 12, and then acquires the reception level from the reception level detector 14 for each of the plurality of reception beams, thereby acquiring the reception level of each of the plurality of reception beams. Note that the number of reception beams may be determined in advance, or may be variable.

[0027] Next, the beam controller 15 calculates the gradient between the receiving beams of the reception levels acquired in step Sa2, and calculates the tracking direction by combining them (step Sa3). That is, the vector resulting from the combination becomes the tracking direction. The gradient between the combined receiving beams may be the gradient between diagonal receiving beams as shown in FIG. 3, or may be the gradient between receiving beams along the periphery. For example, in the case of FIG. 3, the gradient between receiving beams along the periphery is the gradient between receiving beams BR1 and BR2, the gradient between receiving beams BR2 and BR3, the gradient between receiving beams BR3 and BR4, and the gradient between receiving beams BR4 and BR1, and these may be combined.

[0028] Next, the beam controller 15 determines the magnitude of the movement amount and the amplitude of the next conical scan based on the synthesis result in step Sa3 (step Sa4). The beam controller 15 may store in advance a table that associates the range of the magnitude of the vector of the synthesis result with the amplitude, and may use the table to determine the amplitude of the next conical scan. Alternatively, the beam controller 15 may store in advance a relational expression between the magnitude and amplitude of the vector of the synthesis result, and may use the relational expression to determine the amplitude of the next conical scan. The beam controller 15 may increase the amplitude of the next conical scan as the magnitude of the vector of the synthesis result increases. This increases the amplitude when the direction of the remote station is far from the rotation axis (the rotation axis is far from the peak position of the reception level) and the gradient of the reception level is large, thereby reducing the tracking delay.

[0029] Next, the beam controller 15 moves the rotation axis in the tracking direction determined in step Sa3 by the amount of movement determined in step Sa4 to determine the rotation axis of the next conical scan (step Sa5). Next, the beam controller 15 returns to step Sa2 to perform the next conical scan. In the conical scan of step Sa2, multiple reception beams are determined using the rotation axis determined in step Sa5 and the swing width determined in step Sa4.

[0030] In this manner, the beam controller 15 repeats the conical scan to capture and track the remote station.

[0031] Fig. 5 is a graph showing an example of the transition of the reception level at the start of the conical scan in this embodiment. In Fig. 5, the horizontal axis is the time [ms] from the start of the conical scan, and the vertical axis is the reception level [mW]. Graph G1 shows the transition of the reception level over time when there is no noise in the received signal, and graph G2 shows the transition of the reception level over time when the received signal contains noise.

[0032] Regardless of whether noise is present or not, the conical scan in this embodiment reaches a peak reception level between 800 ms and 850 ms. In this way, the number of times the reception level is acquired is significantly reduced compared to the conventional method, but the signal from the other station can be captured and tracked without being affected by noise.

[0033] FIG. 6 is a graph showing an example of signal tracking by conventional conical scanning. In FIG. 6, the horizontal axis represents time [seconds], and the vertical axis represents the reception level. The graph G3 in FIG. 6 shows the transition of the reception level when conical scanning is not performed, and the graph G4 shows the transition of the reception level when conventional conical scanning is being performed. In FIG. 6, at the 20-second mark, the antenna is rotated in the azimuth direction so as to deliberately face in a direction different from that of the other station. In the graph G3 where conical scanning is not performed, the signal of the other station cannot be captured and tracked, and the reception level after 20 seconds remains low. On the other hand, in the graph G4 where conical scanning is performed, the reception level has recovered, but it takes about 15 seconds to recover. Thus, in the example of FIG. 5, the signal of the other station can be captured and tracked in a shorter time than in the example of FIG. 6.

[0034] Further, the present invention may also be in the following embodiments. (1) One embodiment is a beam controller that controls the direction of the reception beam of an antenna that performs conical scanning, obtains the reception level in each of a plurality of reception beams in the current conical scanning, and determines a plurality of reception beams in the next conical scanning based on the gradient of the reception level.

[0035] (2) Another embodiment is the beam controller according to (1), wherein a plurality of reception beams in each conical scan are determined based on at least the rotation axis and the amplitude from the rotation axis, and the rotation axis of the second conical scan, which is the next scan after the first scan, is determined by moving the rotation axis of the first conical scan in the tracking direction by the amount of movement, and the tracking direction is calculated by synthesizing the gradients between the reception beams of the reception levels in each of the plurality of reception beams in the first conical scan.

[0036] (3) Another embodiment is the beam controller according to (2), wherein the smaller the synthesis result of the gradient of the reception level, the smaller the amount of movement.

[0037] (4) Also, another embodiment is a beam controller as described in (2) or (3), which determines an amplitude in the second conical scan based on a combined result of gradients of reception levels in each of the multiple reception beams in the first conical scan.

[0038] (5) In another embodiment, a wireless communication device includes a beam control unit that controls the direction of a receiving beam of an antenna performing a conical scan, and the beam control unit acquires a receiving level for each of multiple receiving beams in the current conical scan and determines multiple receiving beams for the next conical scan based on a gradient of the receiving levels.

[0039] (5) Another embodiment is a beam control method for controlling the direction of a receiving beam of an antenna performing a conical scan, the beam control method including a step of acquiring a receiving level for each of a plurality of receiving beams in the current conical scan, and a step of determining a plurality of receiving beams in the next conical scan based on a gradient of the receiving levels.

[0040] 1 may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed to realize beam controller 15. Note that the term "computer system" here includes hardware such as an OS and peripheral devices.

[0041] In addition, "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 computer systems. Furthermore, "computer-readable recording medium" also includes those that dynamically hold a program for a short period of time, such as 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, such as volatile memory inside a computer system that serves as a server or client in such cases. Furthermore, the above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0042] Although an 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 design changes and the like that do not deviate from the gist of the present invention are also included. [Explanation of symbols]

[0043] 10 Wireless communication devices 11 Antenna 12 Beam Generator 13 Data Receiver 14 Reception level detector 15 Beam Controller

Claims

1. A beam controller for controlling the direction of a receiving beam of an antenna performing conical scanning, A beam controller that acquires a reception level for each of a plurality of reception beams in the current conical scan, and determines a plurality of reception beams in the next conical scan based on a gradient of the reception levels.

2. The plurality of receiving beams in each conical scan are determined based on at least a rotation axis and a swing width from the rotation axis, the rotation axis of the second conical scan, which is the next one after the first one, is determined by moving the rotation axis of the first conical scan in the tracking direction by the amount of movement, Calculating the tracking direction by synthesizing gradients between the reception beams of reception levels in each of the plurality of reception beams in the first conical scan.

2. The beam controller of claim 1.

3. The smaller the combined result of the gradients of the reception levels is, the smaller the amount of movement is made.

3. The beam controller according to claim 2.

4. determining a swing width in the second conical scan based on a result of combining gradients of reception levels in each of the plurality of reception beams in the first conical scan; 3. The beam controller according to claim 2.

5. A beam control unit is provided for controlling the direction of a receiving beam of an antenna performing a conical scan, The beam control unit acquires a reception level for each of a plurality of reception beams in the current conical scan, and determines a plurality of reception beams in the next conical scan based on a gradient of the reception levels. Wireless communication device.

6. A beam control method for controlling a direction of a receiving beam of an antenna performing conical scanning, comprising: acquiring a reception level for each of a plurality of reception beams in the current conical scan; determining a plurality of receive beams in a next conical scan based on the gradient of the receive level; A beam control method comprising:

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