Wireless communication device and calibration method

Abstract

To provide a wireless communication device capable of accurately calibrating antenna paths while reducing the burden on a worker, and a calibration method.SOLUTION: A wireless communication device and the wireless communication method are a device and method for communicating using multiple antennas. In the wireless communication device and the calibration method, a computing unit 24 that performs calibration on the antenna paths, adjusts and identifies a reference signal so that the phase of the reference signal is optimized for one transmitting antenna path, and calibrates other transmitting antenna paths using the identified reference signal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a wireless communication device that performs communication using a plurality of antennas, and more particularly to a wireless communication device and a calibration method that can easily and accurately perform calibration to adjust the phase and level of each antenna path. [Background technology]

[0002] Description of the Prior Art In recent years, the spread of smartphones and other devices has led to a rapid increase in traffic in mobile communication systems. In the future, the introduction of next-generation systems is expected for mobile communication systems, due to the pursuit of convenience and the declining population, and countries are moving from the fourth generation (4G) to the fifth and sixth generations (5G and 6G), with the aim of achieving high speed, large capacity, low latency, and multiple simultaneous connections.

[0003] In particular, for high-speed, large-capacity, and multiple simultaneous connections, there is a demand for efficient communication using technologies such as Massive MIMO (Multiple Input Multiple Output), distributed antennas, and beamforming, and there is a need for high-precision antenna beamforming that is low power consumption and inexpensive. In recent years, active phased array antennas in which multiple antennas are arranged have been adopted to achieve beamforming.

[0004] In an active phased array antenna, a transmit / receive module (T / R module) is arranged, which includes a phase shifter that can arbitrarily adjust the phase of the transmit path and receive path for each antenna element (or for several elements). This allows for beam direction control and spatial power combining to obtain a large transmit output.

[0005] However, an active phased array antenna is premised on there being no variation in level and phase between the antennas, and requires adjustment (calibration) to eliminate phase and level differences between the antennas.

[0006] Conventionally, the method for adjusting the level and phase variations in the transmission line (antenna path) from the signal processing unit to each antenna involves synthesizing a relative comparison signal with a signal that is 180 degrees out of phase, and having an operator adjust the level and phase while checking the waveform, etc. with a measuring instrument, etc. However, such an adjustment method requires complicated and time-consuming work, and it is difficult to judge the adjustment results, leading to variations due to human error.

[0007] [Related Technology] Incidentally, a conventional technique relating to the calibration of a communication device using a plurality of antennas is disclosed in Japanese Patent Laid-Open Publication No. 2001-185933 entitled "Adaptive Array Antenna Transmitter and Receiver" (Patent Document 1). Patent Document 1 describes a technique that enables a transmitter and a receiver connected to an array antenna to be calibrated individually. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2001-185933 A Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, in conventional wireless communication devices equipped with multiple antennas, adjustments of the levels and phases between antenna paths were performed by operators, which resulted in problems such as cumbersome work and variations due to human factors.

[0010] Incidentally, Patent Document 1 does not describe identifying a reference signal that has an optimal phase for a specific antenna path among multiple antennas, and then adjusting the phase and level of other antenna paths using the specific antenna path and the reference signal with the optimal phase.

[0011] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a wireless communication device and a calibration method that can reduce the burden on an operator and easily and accurately calibrate an antenna path. [Means for solving the problem]

[0013] The present invention, which aims to solve the problems of the above-mentioned conventional example, is a wireless communication device that performs communication using a plurality of antennas, and for an antenna path for transmission by a specific antenna, A first phase control circuit having a first port for receiving an input signal and a reference signal for transmission by a specific antenna, delaying the phases of the input signal and the reference signal by 90° and 180°, and combining and outputting the reference signal delayed by 90° and the input signal delayed by 180°, and a second port for combining and outputting the input signal delayed by 90° and the reference signal delayed by 180°, a third port for receiving a signal from the first port and a signal from the second port, delaying the phase of each by 90°, and combining and outputting the combined signal, and a fourth port for delaying the phase of the signal from the first port by 270° and the signal from the second port by 90°, and combining and outputting the combined signal, a combining circuit for combining an output signal from the third port and an output signal from the fourth port, and a phase control circuit for changing the phase of the reference signal and outputting the combined signal from the combining circuit. level and a control unit that identifies the phase of a reference signal for which the phase is minimum, and performs calibration on antenna paths for transmission of a plurality of antennas using the reference signal of the identified phase.

[0014] In addition, the present invention provides a wireless communication device, which is capable of detecting an antenna path other than the specific antenna. When performing calibration , A first phase control circuit Identified reference signal a second phase control circuit inputs the signal from the first phase control circuit and a signal obtained by delaying the phase of a transmission signal of another antenna path by 180°, delays the phase of each by 90° and combines and outputs the combined signal from a third port and a fourth port by delaying the phase of each by 270°, a combiner circuit combines and outputs the output signal from the third port and the output signal from the fourth port, and a control unit adjusts the phase of the transmission signal of the other antenna path so that the level of the signal combined by the combiner circuit is maximized, It is characterized by performing calibration on the antenna path.

[0015] Further, the present invention provides the wireless communication device, The second phase control circuit includes a switch for switching and connecting the antenna paths of the plurality of antennas, and sequentially switches and inputs transmission signals from the plurality of antenna paths as transmission signals of other antenna paths, and the control unit sequentially calibrates the antenna paths for each of the plurality of antenna paths. It is characterized by the following. is doing.

[0016] The present invention also provides a calibration method for communication using a plurality of antennas, the method comprising the steps of: A first phase control circuit inputs an input signal and a reference signal for transmission by a specific antenna from a first port, delays the phases of the input signal and the reference signal by 90° and 180°, combines and outputs the reference signal delayed by 90° and the input signal delayed by 180°, and combines and outputs the input signal delayed by 90° and the reference signal delayed by 180° from a second port; a second phase control circuit inputs a signal from the first port and a signal from the second port from a third port, delays the phase of each by 90° and combines and outputs the combined signals, and delays the phase of the signal from the first port by 270° and the signal from the second port by 90° from a fourth port; a combiner circuit combines an output signal from the third port and an output signal from the fourth port; a control unit changes the phase of the reference signal so that the level of the signal combined by the combiner circuit becomes minimum. Reference Signal Phase of and calibrating the antenna paths for transmitting from a plurality of antennas using a reference signal of the identified phase. Effect of the Invention

[0017] According to the present invention, there is provided a wireless communication device that performs communication using a plurality of antennas, and a method for transmitting a specific antenna using an antenna path for transmitting a specific antenna is provided. a first phase control circuit having a first port for inputting an input signal and a reference signal, delaying the phases of the input signal and the reference signal by 90° and 180°, and combining and outputting the reference signal delayed by 90° and the input signal delayed by 180°; a second port for combining and outputting the input signal delayed by 90° and the reference signal delayed by 180°; a third port for inputting a signal from the first port and a signal from the second port, delaying the phase of each by 90°, and combining and outputting the combined signal; a fourth port for delaying the phase of the signal from the first port by 270° and delaying the phase of the signal from the second port by 90°; a combining circuit for combining an output signal from the third port and an output signal from the fourth port; and a control circuit for changing the phase of the reference signal so that the level of the signal combined by the combining circuit is minimized. Reference Signal Phase of Identify hand, Calibrating antenna paths for transmitting multiple antennas using the reference signal with the identified phase A control unit Since the device is a wireless communication device, it can perform calibration by itself, which reduces the burden on the operator and enables more accurate calibration of the transmission path.

[0018] In addition, according to the present invention, for antenna paths other than a specific antenna, When performing calibration , A first phase control circuit Identified reference signal a second phase control circuit inputs the signal from the first phase control circuit and a signal obtained by delaying the phase of a transmission signal of another antenna path by 180°, delays the phase of each by 90° and combines and outputs the combined signal from a third port and a fourth port by delaying the phase of each by 270°, a combiner circuit combines and outputs the output signal from the third port and the output signal from the fourth port, and a control unit adjusts the phase of the transmission signal of the other antenna path so that the level of the signal combined by the combiner circuit is maximized, Since the wireless communication device performs calibration on the antenna paths, it has an advantage that calibration of the receiving antenna paths can be easily performed for each of the multiple antennas.

[0020] According to the present invention, there is provided a calibration method for communication using a plurality of antennas, the method comprising the steps of: A first phase control circuit inputs an input signal and a reference signal for transmission by a specific antenna from a first port, delays the phases of the input signal and the reference signal by 90° and 180°, combines and outputs the reference signal delayed by 90° and the input signal delayed by 180°, and combines and outputs the input signal delayed by 90° and the reference signal delayed by 180° from a second port; a second phase control circuit inputs a signal from the first port and a signal from the second port from a third port, delays the phase of each by 90° and combines and outputs the combined signals, and delays the phase of the signal from the first port by 270° and the signal from the second port by 90° from a fourth port; a combiner circuit combines an output signal from the third port and an output signal from the fourth port; a control unit changes the phase of the reference signal so that the level of the signal combined by the combiner circuit becomes minimum. Reference Signal Phase ofSince this is a calibration method in which a reference signal of a phase that is determined by a phase difference between the antenna elements is used to calibrate the antenna paths for transmission of a plurality of antennas, the calibration can be performed by the device alone, which has the effect of reducing the burden on the operator and enabling more accurate calibration of the transmission paths. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is an explanatory diagram showing the configuration of the wireless communication device. [Diagram 2] FIG. 2 is an explanatory diagram showing input and output signals of the 90° hybrid circuits (1) and (2) during operation. [Diagram 3] FIG. 11 is an explanatory diagram showing calibration of a transmitting antenna path. [Figure 4] 4 is an explanatory diagram showing input / output signals (A pattern) of the rat race circuit 21. FIG. [Diagram 5] 4 is an explanatory diagram showing input / output signals (B pattern) of the rat race circuit 21. FIG. [Figure 6] 4 is an explanatory diagram showing input / output signals (C pattern) of the rat race circuit 21. FIG. [Figure 7] 4 is an explanatory diagram showing input / output signals (D pattern) of the rat race circuit 21. FIG. [Figure 8] FIG. 11 is an explanatory diagram showing calibration of another antenna path. [Figure 9] FIG. 11 is an explanatory diagram showing calibration of a receiving antenna path. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. [Outline of the embodiment] A wireless communication device according to an embodiment of the present invention (this wireless communication device) is a wireless communication device that communicates using multiple antennas, and is equipped with a calibration unit that performs calibration on the antenna paths.The device performs calibration on its own, adjusts and identifies the phase of a reference signal for one transmitting antenna path so that it is optimal, and calibrates the other transmitting antenna paths using the identified reference signal.This reduces the burden on operators and makes it possible to more accurately adjust the phase and level of the transmitting antenna paths. The configuration of the calibration unit will be described later. Moreover, the calibration method according to the embodiment of the present invention is a calibration method for the wireless communication device.

[0023] Specifically, in the calibration section of this wireless communication device, a 90° hybrid circuit receives an input signal and a reference signal for transmission, delays the phases of the input signal and the reference signal by 90° and 180°, combines and outputs the reference signal delayed by 90° and the input signal delayed by 180° from a first port, and combines and outputs the input signal delayed by 90° and the reference signal delayed by 180° from a second port, and a rat race circuit receives a signal from the first port and a signal from the second port, delays the phase of each by 90°, and outputs a third signal. The signal from the first port is phase-delayed by 270° and the signal from the second port is phase-delayed by 90° and then combined and output from the fourth port. The combining circuit combines the output signal from the third port and the output signal from the fourth port of the rat race circuit. A calculator changes the phase of the reference signal and identifies the phase of the reference signal that minimizes the power of the signal combined by the combining circuit to create a specific reference signal. This wireless communication device performs calibration on the antenna path using the specific reference signal.

[0024] [Configuration of this wireless communication device (normal operation): Figure 1] The configuration of this wireless communication device will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram showing the configuration of this wireless communication device. Note that in Fig. 1, only one antenna is shown for simplicity of explanation, but in reality, multiple antennas are provided. Also, the arrows in Fig. 1 indicate the flow of signals during transmission in normal operation.

[0025] As shown in FIG. 1, the wireless communication device includes a transmit / receive switch 11, output switches 12 and 13, a terminator 14, an antenna 15, a 90° hybrid circuit (1) 16, a 90° hybrid circuit (2) 17, a rat race circuit 21, a synthesis circuit 22, a reference signal switch 23, a calculator 24, a memory device 25, and an n-wavelength line 26.

[0026] The transmission / reception changeover switch 11 is a switch that switches between transmission and reception in a time-division manner. The output changeover switch 12 changes the output destination from the P4 port of the 90° hybrid circuit (2) 17. The output changeover switch 13 changes the output destination from the P3 port of the 90° hybrid circuit (2) 17. The terminator 14 terminates the input signal.

[0027] The 90° hybrid circuit (1) 16 and the 90° hybrid circuit (2) 17 delay the phases of signals input from two input ports (P1, P2) by 90° and 180°, respectively, combine the signals, and output the combined signals from two output ports (P3, P4). The 90° hybrid circuit (1) 16 corresponds to a first phase control circuit in the claims. The P3 port of the 90° hybrid circuit (1) 16 corresponds to a first port in the claims, and the P4 port of the 90° hybrid circuit (1) 16 corresponds to a second port in the claims.

[0028] The 90° hybrid circuit (1) 16, the 90° hybrid circuit (2) 17, the rat race circuit 21, the synthesis circuit 22, the reference signal changeover switch 23, the calculator 24, the storage device 25, and the n-wavelength line 26 constitute a calibration section, which is a characteristic part of this wireless communication device. The calibration section will be described later.

[0029] During normal operation, when transmitting, a TX signal (transmitting signal) from the signal processing unit is input to the P1 port of the 90° hybrid circuit (1) 16, a signal delayed by 90° is output from the P4 port, and a signal delayed by 180° is output from the P3 port. A reference signal is input to the P2 port of the 90° hybrid circuit (1) 16 during calibration as described below, but is not input during operation.

[0030] The output from P4 of the 90° hybrid circuit (1) 16 is input to the P1 port of the 90° hybrid circuit (2) 17, and the output from P3 of the 90° hybrid circuit (1) 16 is input to the P2 port of the 90° hybrid circuit (2) 17, and these are phase-converted, combined, and output from the P4 port and the P3 port. During normal operation, the P4 port, to which no antenna is connected, produces a composite signal of opposite phase, so that the TX signal is not output, but is output only from the P3 port and transmitted from the antenna 15 via the output changeover switch 13.

[0031] [Input and output of the 90° hybrid circuit during normal operation: Figure 2] Before explaining the calibration unit, the input and output of the 90° hybrid circuit (1) 16 and the 90° hybrid circuit (2) 17 during normal operation will be explained using Fig. 2. Fig. 2 is an explanatory diagram showing input and output signals of the 90° hybrid circuits (1) and (2) during operation. 2, when a TX signal (phase 0°) is input from the P1 port of the 90° hybrid circuit (1) 16, a signal delayed by 90° is output from the P4 port, and a signal delayed by 180° is output from the P3 port. In this specification, the phases of each signal are shown by circles and arrows for easy understanding. Then, they are input to the P1 and P2 ports of the 90° hybrid circuit (2) 17, respectively.

[0032] At the P4 port of the 90° hybrid circuit (2) 17, the signal input from the P1 port is delayed by a further 90° to a signal delayed by 180°, and the signal input from the P2 port is delayed by a further 180° to a signal delayed by 0°, so that no output is produced.

[0033] In addition, at the P3 port of the 90° hybrid circuit (2) 17, the signal input from the P2 port is delayed by a further 90° to become a signal delayed by 270°, and the signal input from the P1 port is delayed by a further 180° to become a signal delayed by 270°, thereby obtaining a high level output. As a result, during normal operation, a TX signal is output to the port to which the antenna 15 is connected, and there is no output from the port to which the antenna 15 is not connected.

[0034] [Configuration of the calibration section: Figure 1] Next, the configuration of the calibration unit, which is a characteristic part of this wireless communication device, will be described with reference to FIG. As described above, the calibration unit includes, in addition to the above-mentioned 90° hybrid circuit (1) 16 and 90° hybrid circuit (2) 17, a rat race circuit 21, a synthesis circuit 22, a reference signal switching switch 23, a calculator 24, a memory device 25, and an n-wavelength line 26.

[0035] The rat race circuit (180° hybrid circuit) 21 inputs the output from the P3 port of the 90° hybrid circuit (1) 16 to its P1 port, and inputs the output from the P4 port of the 90° hybrid circuit (1) 16 to its P3 port, delays the phase of each by a specified amount, combines them, and outputs them from the P2 port and the P4 port. The rat race circuit 21 corresponds to the second phase control circuit recited in the claims. The P2 port of the rat race circuit 21 corresponds to the third port recited in the claims, and the P4 port of the rat race circuit 21 corresponds to the fourth port recited in the claims.

[0036] The synthesis circuit 22 receives and synthesizes the output signals from the P2 and P4 ports of the rat race circuit 21, and outputs the result to the calculator 24. The storage device 25 stores processing programs executed by the computing device 24 and various data. The n-wavelength line 26 is a line having n wavelengths corresponding to the desired signal frequency.

[0037] The calculator 24 is a control unit that performs the calibration process, generates a reference signal used in the calibration, first selects an arbitrary antenna, and specifies the phase of the optimal reference signal in accordance with the transmission signal (TX signal) from the antenna. The reference signal whose phase has been specified is called a specified reference signal. Then, in this wireless communication device, once the specific reference signal is determined, calibration of the transmission paths is performed for the other antennas, and thereafter calibration of the reception paths is performed to match the phase of the transmission paths.

[0038] The specific operation will be described later, but the calculator 24 monitors the level of the composite signal input from the combiner circuit 22, adjusts the phase of the reference signal so that the level of the composite signal is minimized, and sets it as a specific reference signal. As will be described later, the calculator 24 also receives the outputs of the P2 and P4 ports of the rat race circuit 21 before combining.

[0039] The calculator 24 also adjusts the phase of the TX signal of the other antenna path using the specific reference signal and the TX signal of the antenna path used to obtain the specific reference signal. The calculator 24 monitors the level of the combined signal input from the combining circuit 22, and adjusts the phase of the TX signal of the other antenna path so that the level of the combined signal is maximized. The calculator 24 corresponds to the control section recited in the claims.

[0040] The reference signal changeover switch 23 switches the output destination of the reference signal between the P2 port of the 90° hybrid circuit (1) 16 or the n-wavelength line 26. The reference signal changeover switch 23 is switched to the P2 port side of the 90° hybrid circuit (1) 16 when determining the optimal phase of the reference signal and when adjusting the phase of the TX signal of the antenna 15, and is switched to the n-wavelength line 26 side when adjusting the phase of the receiving path of the antenna 15.

[0041] [Calibration of the transmitting antenna path: Figure 3] Next, the calibration of the antenna path during transmission will be described with reference to Fig. 3. Fig. 3 is an explanatory diagram showing the calibration of the transmitting antenna path. As shown in FIG. 3, calibration is performed with the reference signal changeover switch 23 switched to the P2 port side of the 90° hybrid circuit (1) 16 and the output changeover switch 13 switched to the terminator 14 side.

[0042] As described above, in the wireless communication device, the optimum phase of a reference signal is first identified for a single antenna, and the identified reference signal is used to calibrate other antenna paths.

[0043] The operation for determining the specific reference signal will now be described. A TX signal transmitted from an arbitrary antenna 15 is input to a P1 port of a 90° hybrid circuit (1) 16 via a transmission / reception switching signal 11. The antenna 15 corresponds to a specific antenna recited in the claims. Further, the reference signal from the calculator 24 is input to the P2 port of the 90° hybrid circuit (1) 16 via the reference signal changeover switch 23.

[0044] Then, in the 90° hybrid circuit (1) 16, the TX signal and the reference signal are phase-controlled and combined, and the combined signal is output from the P3 port and the P4 port. Specifically, a TX signal delayed by 180° and a reference signal delayed by 90° are combined and output from the P3 port, and a TX signal delayed by 90° and a reference signal delayed by 180° are combined and output from the P4 port.

[0045] The output signal from the P3 port of the 90° hybrid circuit (1) 16 is input to the P1 port of the rat race circuit 21, and the output signal from the P4 port of the 90° hybrid circuit (1) 16 is input to the P3 port of the rat race circuit 21.

[0046] In the rat race circuit 21, the input signals are phase-controlled and combined, and the combined signals are output from the P2 port and the P4 port. The input and output signals of the rat race circuit 21 will be described later.

[0047] The output signals from the P2 and P4 ports of the rat race circuit 21 are input to a synthesis circuit 22 where they are synthesized, and then input to a computing unit 24. The calculator 24 adjusts the phase of the reference signal so that the level of the combined signal from the combiner circuit 22 becomes minimum. At this time, the calculator 24 inputs the output signals (P2 port, P4 port) of the rat race circuit 21 before synthesis and adjusts the phase of the reference signal while also referring to these signals. This makes it possible to determine the phase adjustment direction (rotation direction) and quickly optimize the phase of the reference signal.

[0048] The phase-optimized reference signal becomes the specific reference signal. In addition, the level and phase of the TX signal of the antenna path (antenna 15 in this example) used to obtain the specific reference signal is adjusted to synchronize with the specific reference signal. The antenna path used to obtain the specific reference signal is referred to as the "adjusted antenna path."

[0049] In this way, with this wireless communication device, the device can perform calibration on its own, eliminating the need for operation by an operator, reducing the burden on the operator, preventing variations due to human factors, and enabling more accurate and high-precision adjustments to be made.

[0050] Furthermore, in this wireless communication device, the calculator 24 monitors the level of the combined signal from the combining circuit 22 and adjusts the phase of the reference signal based on that level, eliminating the need for complex calculation processing and enabling quick adjustment with simple processing.

[0051] Then, the wireless communication device calibrates the other antenna paths using the specific reference signal and the TX signal from the adjusted antenna path. The same specific reference signal is used in the adjustment of the other antenna paths, so that the multiple antenna paths all have the same level and phase.

[0052] [Input and output of rat race circuit 21: Figures 4 to 7] Here, input and output signals of the rat race circuit 21 when determining the specific reference signal will be described with reference to FIG. Figure 4 is an explanatory diagram showing the input / output signals (pattern A) of the rat race circuit 21 when determining a specific reference signal, Figure 5 is an explanatory diagram showing the input / output signals (pattern B) of the rat race circuit 21 when determining a specific reference signal, Figure 6 is an explanatory diagram showing the input / output signals (pattern C) of the rat race circuit 21 when determining a specific reference signal, and Figure 7 is an explanatory diagram showing the input / output signals (pattern D) of the rat race circuit 21 when determining a specific reference signal.

[0053] 4 to 7 show a representative example in which a TX signal of an arbitrary antenna path is fixed and input to the P1 port of the 90° hybrid circuit (1) 16, and the phase of a reference signal is changed and input to the P2 port. In the A pattern shown in Fig. 4, the phase of the reference signal is delayed by 90 degrees (hereinafter simply referred to as 90 degrees) with respect to the TX signal (phase 0 degrees), and at the P3 port, the TX signal delayed by 180 degrees and the reference signal delayed by 90 degrees are in phase and combined. At the P4 port, the TX signal delayed by 90 degrees and the reference signal delayed by 180 degrees are out of phase and combined, resulting in no output. Therefore, there is no input to the P3 port of the rat race circuit 21.

[0054] Then, the output signal from the P3 port of the 90° hybrid circuit (1) 16 is input to the P1 port of the rat race circuit 21, output from the P2 port with a delay of 90°, and output from the P4 port with a delay of 270°, and each is input to the combining circuit 22 and combined. As shown in FIG. 4, the output from the P2 port of the rat race circuit 21 is −6 dB at 270°, and the output from the P4 port is −6 dB at 90°, so that the level of the combined signal output from the combining circuit 22 is at a minimum.

[0055] 5, the phase of the reference signal is 180° with respect to the phase of the TX signal being 0°. In this case, the signals are combined in the 90° hybrid circuit (1) 16, and a 225° signal is input to the P1 port of the rat race circuit 21, and a 45° signal is input to the P3 port. Then, there is no output from the P2 port of the rat race circuit 21, the output from the P4 port is −6 dB at 135°, and the level of the combined signal from the combiner circuit 22 is −6 dB.

[0056] In pattern C shown in Figure 6, the phase of the reference signal is 270°, the output from port P2 of rat race circuit 21 is -6dB at 180°, the output from port P4 is also -6dB at 180°, and the level of the combined signal from combining circuit 22 is -3dB.

[0057] In addition, in the D pattern shown in Figure 7, the phase of the reference signal is 0°, the same as the TX signal, the output from the P2 port of the rat race circuit 21 is -6dB at 225°, there is no output from the P4 port, and the level of the combined signal from the combining circuit 22 is -6dB. In other words, as shown in Figures 4 to 7, when the phase of the reference signal is delayed by 90° relative to the TX signal (Figure 4, pattern A), the level of the combined signal from the combining circuit 22 becomes minimum, and the calculator 24 sets the reference signal as a specific reference signal.

[0058] [Calibration of other antenna paths: Figure 8] Next, an operation for performing calibration for an antenna path other than the antenna path (adjusted antenna path) used when obtaining a specific reference signal will be described with reference to Fig. 8. Fig. 8 is an explanatory diagram showing the calibration of another antenna path. As shown in FIG. 8, when calibrating the antenna path of the transmission signal of another antenna 40, a combining antenna changeover switch 41 and a 90° hybrid circuit (1) 42 and a 90° hybrid circuit (2) 43 corresponding to the other antenna are provided.

[0059] The combining antenna changeover switch 41 is a switch that switches the TX signal of the antenna to be calibrated and inputs it to the P3 port of the rat race circuit 21. Here, only antenna 40 is shown as another antenna, and the path of antenna 40 is connected to rat race circuit 21, but if more antennas are provided, they will be connected by a switch that switches them sequentially.

[0060] The other antennas 40 are then calibrated using the specific reference signal and the TX signal of the adjusted antenna path. As shown in FIG. 8, when a TX signal (phase 0°) of the adjusted antenna path is input from the P1 port of the 90° hybrid circuit (1) 16 and a specific reference signal (phase 90°) is input from the P2 port, 4 Port has no signal, P3 The port outputs a composite signal with a phase of 180°. P 3 The output from the port is input to the P1 port of the rat race circuit 21.

[0061] On the other hand, in the path of the antenna 40, a TX signal with a phase of 0° is input to the P1 port of the 90° hybrid circuit (1) 42, and a TX signal with a phase of 180° is output from the P3 port and input to the P3 port of the rat race circuit 21 via the combining antenna switching switch 41.

[0062] Ideally, the inputs to the P1 and P4 ports are combined at a phase of 270° at the P2 port of the rat race circuit 21 to produce a maximum signal, and at the P4 port, the inputs are combined at 90° and 270° to produce no signal, which is then input to the combining circuit 22. If the phase of the TX signal of antenna 40 is out of phase with the adjusted TX signal of antenna 15, the output of port P2 will be at a lower level than the ideal level.

[0063] The combiner circuit 22 combines the outputs of the P2 and P4 ports of the rat race circuit 21 and outputs a combined signal to the calculator 24. Then, the calculator 24 adjusts the phase and level of the TX signal of the antenna 40 so that the level of the composite signal is maximized. This causes the antenna 40 path to match in phase and level with the tuned antenna 15 path.

[0064] Furthermore, even if there are more antenna paths, adjustments can be made in a similar manner, making it possible to easily calibrate a plurality of antennas. As a result, in this wireless communication device, it is possible to prevent artificial variations that occur when an operator adjusts the phase, and to perform calibration quickly and accurately.

[0065] [Calibration of receiving antenna path: Figure 9] Next, the calibration of the receiving antenna path will be described with reference to Fig. 9. Fig. 9 is an explanatory diagram showing the calibration of the receiving antenna path. As shown in Figure 9, in calibration of the receiving antenna path, the reference signal changeover switch 23 is switched to the n-wavelength line 26 side, and a specific reference signal from the calculator 24 is input to the n-wavelength line 26 to be used as a pseudo receiving signal from the antenna 15 side.

[0066] The specific reference signal output from the n-wavelength line 26 is input to the P3 port of the 90° hybrid circuit (2) 17 via the output switching switch 13, phase-controlled, output from the P1 port and the P3 port, and input to the P3 port and the P4 port of the 90° hybrid circuit (1) 16.

[0067] The calculator 24 compares the phase and level of the signal (RX signal / pseudo received signal) output from the P1 port of the 90° hybrid circuit (1) 16 with the phase and level of the TX signal to check whether they match. Normally, the receive antenna path coincides with the transmit antenna path. If they do not match, it is possible that the specific reference signal is no longer optimal due to a shift in the antenna position or angle, etc., so the specific reference signal is calculated again and calibration of the transmitting antenna path is started again.

[0068] Furthermore, in this wireless communication device, the receiving antenna paths of the other antennas 40 are also calibrated in a similar manner. Specifically, the specific reference signal output from the n-wavelength line 26 is connected to the output changeover switch of the other antenna 40, and the output changeover switch is switched to the 90° hybrid circuit (2) 43 side. Then, the calculator 24 checks whether the phase and level of the pseudo reception signal output from the 90° hybrid circuit (1) via the reception path of the antenna 40 match those of the TX signal of the antenna 40. In this manner, it is possible to calibrate the receiving paths for multiple antennas.

[0069] [Effects of the embodiment] According to this wireless communication device, the 90° hybrid circuit (1) 16 receives an input signal for transmission and a reference signal, delays the phases of the input signal and the reference signal by 90° and 180°, combines and outputs the reference signal delayed by 90° and the input signal delayed by 180° from a first port (P3 port), and also combines and outputs the input signal delayed by 90° and the reference signal delayed by 180° from a second port (P4 port). The rat-race circuit 21 receives a signal from the first port and a signal from the second port of the 90° hybrid circuit (1) 16, delays the phase of each by 90°, combines and outputs the combined signal from a third port (P2 port), and also combines and outputs the signal from the first port by delaying the phase of each by 90°. The signal from the second port is phase delayed by 70°, the signal from the third port is phase delayed by 90° and the signal is combined and output from the fourth port (P4 port), the combining circuit 22 combines the output signal from the third port of the rat race circuit 21 with the output signal from the fourth port, and the calculator 24 changes the phase of the reference signal to identify the phase of the reference signal that minimizes the power of the signal combined by the combining circuit 22 to create a specific reference signal, and this specific reference signal is used to perform calibration on the antenna path in a wireless communication device, which makes it possible to perform calibration by the device alone, reducing the burden on the operator and eliminating variations due to human factors, thereby enabling more accurate adjustments. [Industrial Applicability]

[0070] The present invention is suitable for a wireless communication device that can reduce the burden on an operator and perform calibration of an antenna path easily and accurately. [Explanation of symbols]

[0071] 11...transmit / receive switch, 12, 13...output switch, 14...terminator, 15, 40...antenna, 16, 42...90° hybrid circuit (1), 17, 43...90° hybrid circuit (2), 21...rat race circuit, 22...combining circuit, 23...reference signal switch, 24...computer, 25...storage device, 26...n-wavelength line, 41...combining antenna switch

Claims

1. A wireless communication device that communicates using multiple antennas, For an antenna path for transmission by a particular antenna, a first phase control circuit having a first port for receiving an input signal and a reference signal for transmission by the specific antenna, delaying the phases of the input signal and the reference signal by 90° and 180°, and combining and outputting the reference signal delayed by 90° and the input signal delayed by 180°, and a second port for combining and outputting the input signal delayed by 90° and the reference signal delayed by 180°; a second phase control circuit having a third port which receives the signal from the first port and the signal from the second port, delays the phase of each of the signals by 90°, combines the signals, and outputs the combined signal; and a fourth port which delays the phase of the signal from the first port by 270° and delays the phase of the signal from the second port by 90°, and outputs the combined signal; a combining circuit for combining an output signal from the third port and an output signal from the fourth port; a control unit that changes a phase of the reference signal, identifies a phase of the reference signal that results in a minimum level of a signal combined by the combining circuit, and performs calibration on antenna paths for transmission of the multiple antennas using the reference signal of the identified phase.

2. When performing calibration for antenna paths other than the specific antenna, the first phase control circuit outputs a signal obtained by combining a signal obtained by delaying a phase of the identified reference signal by 90° and a transmission signal of an antenna path of the specific antenna; the second phase control circuit receives a signal from the first phase control circuit and a signal obtained by delaying the phase of the transmission signal of the other antenna path by 180°, delays the phase of each of the signals by 90° and combines and outputs the combined signals from the third port, and delays the phase of each of the signals by 270° and combines and outputs the combined signals from the fourth port, the combining circuit combines the output signal from the third port and the output signal from the fourth port and outputs the combined signal; 2. The wireless communication device according to claim 1, wherein the control unit performs calibration on the other antenna path by adjusting a phase of a transmission signal of the other antenna path so that a level of a signal combined by the combining circuit is maximized.

3. The second phase control circuit includes a switch that switches and connects the antenna paths of the plurality of antennas, and sequentially switches and inputs transmission signals from the plurality of antenna paths as transmission signals of the other antenna paths; 3. The wireless communication device according to claim 2, wherein the control unit sequentially performs antenna path calibration for each of the plurality of antenna paths.

4. A calibration method for communication using a plurality of antennas, comprising: For an antenna path for transmission by a particular antenna, a first phase control circuit inputs an input signal and a reference signal for transmission by the specific antenna from a first port, delays the phases of the input signal and the reference signal by 90° and 180°, combines and outputs the reference signal delayed by 90° and the input signal delayed by 180°, and combines and outputs the input signal delayed by 90° and the reference signal delayed by 180° from a second port; a second phase control circuit inputs the signal from the first port and the signal from the second port from a third port, delays the phase of each of the signals by 90°, combines and outputs the combined signals, and delays the phase of the signal from the first port by 270° and the signal from the second port by 90° from a fourth port, a combining circuit combining an output signal from the third port and an output signal from the fourth port; a control unit changes a phase of the reference signal, identifies a phase of the reference signal that results in a minimum level of a signal combined by the combining circuit, and performs calibration on antenna paths for transmission of the multiple antennas using the reference signal of the identified phase.

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