JP7450231B2 - Receiver, receiving system, transmitter, receiving method and program - Google Patents

Description

The present disclosure relates to a receiver, a receiving system, a transmitter, a receiving method, and a program, and more particularly, to a receiver, a receiving system, a transmitter, a receiving method, and a program that generate a plurality of signals.

The communication terminal device (receiver) described in Patent Document 1 estimates the arrival direction of a beacon signal (wireless signal) transmitted by a beacon device (transmitter) based on received signal strength (RSSI).

However, in the communication terminal device (receiver) described in Patent Document 1, an error may occur when estimating the direction of arrival of a beacon signal due to the occurrence of multipath. Therefore, it has been desired to improve the accuracy of estimating the direction of arrival of beacon signals.

JP2017-216567A

The present disclosure has been made in view of the above reasons, and aims to provide a receiver, a reception system, a transmitter, a reception method, and a program that can improve the accuracy of estimating the direction of arrival of a radio signal.

In order to solve the above problems, a receiver according to one aspect of the present disclosure includes a plurality of antennas, a phase combining section, an output section, a changing section, and a switching section . The plurality of antennas receive wireless signals. The phase combining unit performs a combining process on a plurality of input signals based on the wireless signals input from the plurality of antennas, and generates a combined signal for estimating the direction of arrival of the wireless signals. The output section outputs the composite signal. The modification unit performs modification processing to modify at least one element related to processing from reception of the wireless signal to generation of the composite signal. The switching section switches the electrical connection state between the plurality of antennas and the phase combining section. The phase combining section generates a first combined signal as the combined signal before the changing process by the changing section. Further, the phase combining section generates a second combined signal as the combined signal after the changing process by the changing section. The output section outputs the first composite signal and the second composite signal. The phase combining section includes a first input section and a second input section that are electrically connected to one of the plurality of antennas via the switching section and into which the wireless signal is input. The phase synthesis section performs a process of shifting the phase of at least one of the plurality of input signals in the synthesis process. The changing unit performs a process of controlling the switching unit to change the electrical connection state between the plurality of antennas and the phase combining unit, as at least part of the changing process. The connection state includes a first connection state and a second connection state. In the first connection state, the one antenna and the second input section are electrically connected via the switching section. In the second connection state, the one antenna and the first input section are electrically connected via the switching section.

A transmitter according to one aspect of the present disclosure includes a phase combining section, a plurality of antennas, a changing section , and a switching section . The phase synthesis unit performs synthesis processing on a plurality of input signals based on a plurality of original signals, and generates a plurality of radio signals. The plurality of antennas transmit the plurality of radio signals. The change unit performs a change process to change at least one element related to processing from receiving the plurality of original signals to transmitting the plurality of wireless signals. The switching section switches the electrical connection state between the plurality of antennas and the phase combining section. The phase synthesis section generates a plurality of first radio signals as the plurality of radio signals before the modification processing by the modification section. Further, the phase synthesis section generates a plurality of second radio signals as the plurality of radio signals after the modification processing by the modification section. The phase combining section includes a first output section and a second output section that are electrically connected to one of the plurality of antennas via the switching section and output the plurality of radio signals. The antenna transmits the plurality of first radio signals and the plurality of second radio signals. The phase synthesis section performs a process of shifting the phase of at least one of the plurality of input signals in the synthesis process. The changing unit performs a process of controlling the switching unit to change the electrical connection state between the plurality of antennas and the phase combining unit, as at least part of the changing process. The connection state includes a first connection state and a second connection state. In the first connection state, the one antenna and the second output section are electrically connected via the switching section. In the second connection state, the one antenna and the first output section are electrically connected via the switching section.

A reception method according to one aspect of the present disclosure is a method used in a reception system. The reception system includes a plurality of antennas, a phase synthesis section, and a switching section that switches an electrical connection state between the plurality of antennas and the phase synthesis section. The reception method includes a reception step, a first phase synthesis step, a first output step, a change step, a second phase synthesis step, and a second output step. In the receiving step, radio signals are received by the plurality of antennas . In the first phase combining step, the phase combining unit performs a combining process on a plurality of input signals based on the wireless signal, and generates a first combined signal for estimating the direction of arrival of the wireless signal. do. In the first output step, the first composite signal generated in the first phase synthesis step is output. In the changing step, at least one element related to the processing from the receiving step to the first phase synthesis step is changed. In the second phase combining step, after the changing step, a second combined signal different from the first combined signal generated in the first phase combining step is generated. In the second output step, the second composite signal generated in the second phase synthesis step is output. The phase combining section includes a first input section and a second input section that are electrically connected to one of the plurality of antennas via the switching section and into which the wireless signal is input. In the first phase synthesis step and the second phase synthesis step, processing is performed to shift the phase of at least one of the plurality of input signals. In the changing step, the switching unit is controlled to switch the electrical connection state between the plurality of antennas and the phase combining unit. The connection state includes a first connection state and a second connection state. In the first connection state, the one antenna and the second input section are electrically connected via the switching section. In the second connection state, the one antenna and the first input section are electrically connected via the switching section.

A program according to an aspect of the present disclosure causes one or more processors to execute the receiving method.

FIG. 1 is a schematic diagram showing an overview of a receiving system and a transmitter according to the first embodiment. FIG. 2 is a block diagram showing the functional configuration of the receiving system of the first embodiment. FIG. 3 is a schematic diagram showing an overview of a receiving system and a transmitter according to the second embodiment. FIG. 4 is a block diagram showing the functional configuration of a transmitter according to the second embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments described below, common elements are given the same reference numerals, and redundant explanations of the common elements will be omitted.

(First embodiment)
(1) Overview First, an overview of the receiver, reception system, transmitter, reception method, and program according to the present embodiment will be described with reference to FIG. The transmitter 4 of the present embodiment includes, for example, a beacon device that transmits a beacon signal (wireless signal) in accordance with the BLE (Bluetooth (registered trademark) Low Energy) (hereinafter referred to as "BLE") standard. be done. However, the transmitter 4 is not limited to a beacon device that transmits a beacon signal in accordance with the BLE standard. The transmitter 4 may be, for example, a device that transmits a wireless signal in accordance with the WiFi (registered trademark) standard.

The receiving system 1 includes a plurality of (three in the illustrated example) antennas 11 for receiving radio signals transmitted by the transmitter 4. The plurality of antennas 11 of this embodiment are array antennas including an antenna 11a, an antenna 11b, and an antenna 11c. In the following description, when describing a specific antenna 11, the antennas 11a, 11b, and 11c will be described separately. Furthermore, when describing the plurality of antennas 11 without distinguishing them, they are simply referred to as antennas 11.

The reception system 1 of this embodiment is configured as a system capable of receiving wireless signals in accordance with the BLE standard using a plurality of antennas 11. However, the receiving system 1 is not limited to a system that can receive wireless signals in accordance with the BLE standard. The receiving system 1 may be a system capable of receiving wireless signals according to the WiFi standard, for example. The receiving system 1 of this embodiment estimates the position and direction of the transmitter 4 that transmitted the wireless signal based on the received signal strength (RSSI) of the wireless signal received by the plurality of antennas 11.

(2) Details Hereinafter, details of the receiving system 1 according to the present embodiment will be explained with reference to FIGS. 1 and 2.

(2.1) Configuration of Reception System 1 As shown in FIG. 2, the reception system 1 of this embodiment includes a receiver 2 and an estimator 3. Receiver 2 receives the radio signal transmitted by transmitter 4. Upon receiving the radio signal, the receiver 2 generates composite signals SS1 to SS4 for estimating the direction of arrival of the radio signal based on the radio signal. Further, the receiver 2 performs a change process to change at least one element related to the process from receiving the wireless signal to generating the composite signals SS1 to SS4. The composite signals SS1 to SS4 generated by the receiver 2 based on the radio signals become different composite signals SS1 to SS4 before and after performing the modification process. The receiver 2 outputs the composite signals SS1 to SS4 before and after the modification processing to the estimator 3.

The estimation unit 3 estimates the direction of arrival of the radio signal based on the composite signals SS1 to SS4 outputted from the receiver 2 before and after the modification process. The method by which the estimation unit 3 estimates the direction of arrival of a radio signal will be explained in the section "(3) Estimation of direction of arrival".

(2.2) Configuration of receiver 2 As shown in FIG. 2, the receiver 2 includes a plurality of antennas 11, a switching section 12, a phase combining section 13, an output section 14, and a changing section 15. .

The plurality of antennas 11 are electrically connected to the switching section 12. Each of the plurality of antennas 11 receives a radio signal transmitted by the transmitter 4.

The switching unit 12 is a processing unit that is electrically connected between the plurality of antennas 11 and the phase synthesis unit 13 and switches the electrical connection state between the plurality of antennas 11 and the phase synthesis unit 13. The switching section 12 includes a switch 16a, a switch 16b, and a switch 16c. In the following description, when the switches 16a, 16b, and 16c are described without distinction, they will simply be referred to as switch 16. Furthermore, when describing a specific switch 16, the switches 16a, 16b, and 16c will be described separately.

The switching unit 12 performs a switching operation of the switches 16a to 16c under the control of the changing unit 15. The switch 16b of this embodiment is configured to connect the antenna 11b and one of the first input terminal I1 and the second input terminal I2 of the phase synthesizer 17b included in the phase synthesis section 13 according to the control by the changing section 15. Connect electrically. In the following description, the state in which the antenna 11b and the first input terminal I1 of the phase synthesizer 17b are electrically connected by the switch 16b will be referred to as a "first connection state." Further, a state in which the antenna 11b and the second input terminal I2 of the phase synthesizer 17b are electrically connected by the switch 16b will be referred to as a "second connection state."

The switch 16a is controlled so that the antenna 11a and the first input terminal I1 of the phase synthesizer 17a are always electrically connected. That is, the switch 16a of this embodiment does not perform a switching operation. Therefore, the switch 16a may be simply an electrical path connecting the antenna 11a and the first input terminal I1 of the phase synthesizer 17a.

Further, the switch 16c is controlled so that the antenna 11c and the second input terminal I2 of the phase synthesizer 17c are always electrically connected. That is, the switch 16c of this embodiment does not perform a switching operation. Therefore, the switch 16c may be a simple electrical circuit that connects the antenna 11c and the second input terminal I2 of the phase synthesizer 17c.

However, the length of the electrical path from antenna 11a to phase synthesizer 17a, the length of the electrical path from antenna 11b to phase synthesizer 17b, and the length of the electrical path from antenna 11c to phase synthesizer 17c. It is preferable that the lengths are the same. This is because if the lengths of the electrical paths from the antennas 11a to 11c to the phase combiners 17a to 17c are different, the accuracy in estimating the arrival direction of the radio signal will be reduced. Therefore, in this embodiment, the switch 16a, the switch 16b, and the switch 16c are configured by the same switch 16.

The phase synthesis unit 13 performs synthesis processing on a plurality of input signals IS1 to IS3 (signals IS4 to IS7) based on radio signals input from a plurality of antennas 11, and performs synthesis processing for estimating the direction of arrival of the radio signals. This is a processing unit that generates signals SS1 to SS4. Furthermore, the phase synthesis section 13 of this embodiment generates different synthesized signals SS1 to SS4 before and after the switch 16b is switched. Here, in the first connection state, the combined signals SS1 to SS4 generated by the phase combining section 13 are referred to as first combined signals SS1 to SS4. Furthermore, in the second connection state, the combined signals SS1 to SS4 generated by the phase combining section 13 are referred to as second combined signals SS1 to SS4.

The phase synthesizer 13 includes a phase synthesizer 17a, a phase synthesizer 17b, a phase synthesizer 17c, a phase synthesizer 17d, and a phase synthesizer 17e. In the following description, when the phase synthesizers 17a, 17b, 17c, 17d, and 17e are described without distinction, they will simply be referred to as phase synthesizer 17. The phase synthesizer 17 is composed of, for example, a 90-degree hybrid unit (hybrid element). The phase synthesizer 17 of this embodiment generates a signal whose power value is 1/√2 times that of the input signals IS1 to IS3 based on the wireless signals input to the first input terminal I1 and the second input terminal I2. It outputs from the first output terminal O1 and the second output terminal O2. Further, the phase synthesizer 17 outputs a signal having the same phase from the first output terminal O1 and whose phase is delayed by 90 degrees compared to the input signals IS1 to IS3 based on the wireless signal input to the first input terminal I1. The signal is output from the second output terminal O2.

The phase synthesizer 17a outputs, from the first output terminal O1, a signal IS4 having a power value 1/√2 times larger and having the same phase as the input signal IS1 based on the radio signal input to the first input terminal I1.

The phase synthesizer 17b has different input terminals electrically connected to the antenna 11b depending on the connection state. In the first connection state, an input signal IS2 based on a wireless signal is input to the first input terminal I1. In this case, the phase synthesizer 17b outputs from the second output terminal O2 a signal IS5 whose power value is 1/√2 times and whose phase is delayed by 90 degrees compared to the input signal IS2. Further, the phase synthesizer 17b outputs a signal IS6 having a power value 1/√2 times that of the input signal IS2 and having the same phase from the first output terminal O1.

In the second connection state, the input signal IS2 is input to the second input terminal I2. In this case, the phase synthesizer 17b outputs a signal IS5 having a power value 1/√2 times that of the input signal IS2 and having the same phase from the second output terminal O2. Further, the phase synthesizer 17b outputs from the first output terminal O1 a signal IS6 whose power value is 1/√2 and whose phase is delayed by 90 degrees compared to the input signal IS2.

The phase synthesizer 17c outputs, from the second output terminal O2, a signal IS7 having a power value 1/√2 times and having the same phase as the input signal IS3 based on the radio signal input to the second input terminal I2.

The phase synthesizer 17d receives the signal IS4 at the second input terminal I2, and receives the signal IS5 at the first input terminal I1. The phase synthesizer 17d generates a signal whose power value is 1/√2 times that of the signal IS4 and whose phase is delayed by 90 degrees, and a signal whose power value is 1/√2 times that of the signal IS5 and whose phase is delayed by 90 degrees. The added composite signal SS1 is output from the first output terminal O1. In addition, the phase synthesizer 17d generates a signal whose power value is 1/√2 times that of the signal IS4 and has the same phase, and a signal whose power value is 1/√2 times that of the signal IS5 and whose phase is delayed by 90 degrees. , is output from the second output terminal O2.

The phase synthesizer 17e receives the signal IS6 at the second input terminal I2, and receives the signal IS7 at the first input terminal I1. The phase synthesizer 17e outputs a signal whose power value is 1/√2 times that of the signal IS6 and whose phase is delayed by 90 degrees, and a signal whose power value is 1/√2 times that of the signal IS7 and whose phase is delayed by 90 degrees. The added composite signal SS3 is output from the first output terminal O1. Further, the phase synthesizer 17e generates a signal whose power value is 1/√2 times that of the signal IS6 and has the same phase, and a signal whose power value is 1/√2 times that of the signal IS7 and whose phase is delayed by 90 degrees. , is output from the second output terminal O2.

The changing unit 15 is a processing unit that performs a changing process to change at least one element related to the process from receiving a radio signal to generating composite signals SS1 to SS4. The changing unit 15 of this embodiment performs a process of controlling the switching unit 12 to change the electrical connection state between the plurality of antennas 11 and the phase combining unit 13 as at least part of the changing process. Specifically, the changing unit 15 switches the electrical connection state between the antenna 11b and the phase synthesizer 17b by controlling the switch 16b to switch. In the following description, it is assumed that the connection state between the antenna 11b and the phase synthesizer 17b is the first connection state until the change unit 15 performs the change process. Further, it is assumed that after the changing unit 15 performs the changing process, the connection state between the antenna 11b and the phase synthesizer 17b is the second connection state. The changing unit 15 performs the changing process at a predetermined timing. The predetermined timing is, for example, the timing at which the phase synthesizer 13 outputs the composite signals SS1 to SS4, or a certain timing set according to the interval at which the transmitter 4 transmits wireless signals.

The output unit 14 outputs the combined signals SS1 to SS4 generated by the phase combination unit 13 to the estimation unit 3. Specifically, the output unit 14 outputs the first synthesized signals SS1 to SS4 generated by the phase synthesis unit 13 before the change process is performed by the change unit 15, and the phase The second combined signals SS1 to SS4 generated by the combining unit 13 are output to the estimating unit 3.

(3) Direction of Arrival Estimation Next, a method for the estimation unit 3 to estimate the direction of arrival of a radio signal will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the complex propagation channel between the antenna 11a and the transmitting antenna of the transmitter 4 is h1, the complex propagation channel between the antenna 11b and the transmitting antenna is h2, and the complex propagation channel between the antenna 11c and the transmitting antenna is h2. Let h3 be the complex propagation channel. Further, the distance between the antenna 11a and the antenna 11b and the distance between the antenna 11b and the antenna 11c are assumed to be d1. Further, it is assumed that the transmitter 4 is located at an angle θ1 with respect to the broadside direction of the array antenna composed of the antenna 11a, the antenna 11b, and the antenna 11c. First, a case will be described in which the estimator 3 estimates the direction of arrival of a radio signal based on the first composite signals SS1 to SS4.

The propagation channels can be collectively expressed as equation (1).

The correlation matrix of this propagation channel can be expressed as equation (2).

Here, the symbol H represents complex conjugate transposition, and the symbol * represents complex conjugate. Usually, the diagonal terms of the correlation matrix R are real numbers, and the off-diagonal terms are complex numbers. By determining the correlation matrix R, the estimation unit 3 can estimate the direction of arrival of the radio signal. The estimation unit 3 obtains a correlation matrix R based on information regarding received signal strength.

Using the propagation channel of equation (1), the amplitudes of the plurality of first composite signals SS1 to SS4 input to the estimation unit 3 can be expressed as equations (3) to (6).

|y1| represents the amplitude of the composite signal SS1 output from the first output terminal O1 of the phase synthesizer 17d. |y2| represents the amplitude of the composite signal SS2 output from the second output terminal O2 of the phase synthesizer 17d. |y3| represents the amplitude of the composite signal SS3 output from the first output terminal O1 of the phase synthesizer 17e. |y4| represents the amplitude of the composite signal SS4 output from the second output terminal O2 of the phase synthesizer 17e. Furthermore, from the received signal strength, the gain of the channel on the left side of equations (3) to (6) can be expressed as equations (7) to (10).

Focusing on the difference in gain obtained via the phase synthesizer 17d, it can be expressed as equation (12) from the relationship of equation (11).

The real parts of R12 and R21 can be found. Here, α represents the argument angle of R12.

Further, when paying attention to the sum of gains obtained via the phase synthesizer 17d, it can be expressed as equation (13) from the relationship of arithmetic geometric mean.

Here, it is assumed that the propagation loss from the transmitting antenna of the transmitter 4 to the antenna 11a is equal to the propagation loss from the transmitting antenna to the antenna 11b, and |h1| and |h2| are approximately equal. When |h1| and |h2| are approximately equal, α, which is the argument angle of R12, can be expressed as equation (14).

Further, when |h1| and |h2| are approximately equal, it can be expressed as equation (15).

Here, A is a real constant. Among the correlation matrices R shown in equation (2), the correlation matrix related to the combined signals SS1 and SS2 output from the phase synthesizer 17d is defined as R1. When the correlation matrix R1 is expressed using A and α, it can be expressed as equation (16).

Next, focusing on the difference in gain obtained via the phase synthesizer 17e, it can be expressed as equation (17).

The imaginary parts of R23 and R32 can be found. Here, β represents the argument angle of R23. Further, when paying attention to the sum of gains obtained via the phase synthesizer 17e, it can be expressed as equation (18) from the relationship of arithmetic geometric mean.

Here, it is assumed that the propagation loss from the transmitting antenna of the transmitter 4 to the antenna 11b is equal to the propagation loss from the transmitting antenna to the antenna 11c, and |h2| and |h3| are approximately equal. When |h2| and |h3| are approximately equal, β, which is the argument angle of R23, can be expressed as equation (19).

Similarly, when |h2| and |h3| are approximately equal, it can be expressed as equation (20).

Here, B is a real constant. Of the correlation matrix R, the correlation matrix related to the combined signals SS3 and SS4 output from the phase synthesizer 17e is defined as R2. When the correlation matrix R2 is expressed using B and β, Equation (21) is obtained, and the correlation matrix R is estimated.

Here, since the argument is estimated in two ways each for α and β, four solutions are estimated. Therefore, it is necessary to choose a solution for α and β. Here, as the solution for α and β, a combination of solutions with the smallest difference between α and β is selected. The transmitting antenna of the transmitter 4 is sufficiently far away from the antennas 11a, 11b, and 11c, and the directions of the transmitting antennas of the transmitter 4 seen from the antennas 11a, 11b, and 11c can all be considered to be equal to θ (Fig. (see 1). Moreover, the antenna 11a, the antenna 11b, and the antenna 11c are aligned at equal intervals d1. Therefore, the difference in phase delay between h1 and h2 is equal to the difference in phase delay between h2 and h3. Here, α represents the difference in phase delay between h1 and h2, and β represents the difference in phase delay between h2 and h3. That is, α and β can be considered to match. Therefore, by selecting the combination of solutions with the smallest difference between α and β as the solution for α and β, it is possible to narrow down the solution to two solutions.

Moreover, R13 represents the correlation of radio signals between the antenna 11a and the antenna 11c. R13 can be expressed as formula (22) using the obtained |R23|.

From the above, the estimated correlation matrix R can be expressed as equation (23).

The estimator 3 estimates the direction of the transmitter 4 by using the MUSIC (MUltiple SIgnal Classification) method on the correlation matrix R. There are various algorithms for direction estimation using the correlation matrix R, but in this embodiment, a case where the estimation unit 3 performs direction estimation using the MUSIC method will be exemplified.

The correlation matrix R can be expressed by Equation (24) by eigenvalue decomposition.

Here, Equation (25) and Equation (26) are used, and diag[] represents a diagonal matrix.

Further, v1, v2, and v3 are the first, second, and third eigenvectors, respectively. Further, it is assumed that λ1, λ2, and λ3 are the first, second, and third eigenvalues, respectively, and are expressed by equation (27).

Further, it is assumed that λ1 corresponds to power including a signal, and λ2 and λ3 correspond to noise power. In the MUSIC method, the direction of arrival of a radio signal is estimated using equation (28), which is an evaluation equation using such eigenvectors.

Here, equation (29) is called a steering vector.

d is the antenna spacing and λ is the wavelength. The estimation unit 3 substitutes various values for θ0 in equation (28), and determines that the direction in which Pmusic is maximized is the departure direction of the radio signal. In the following description, the direction of arrival estimated by the estimation unit 3 based on the first composite signals SS1 to SS4 will be referred to as a "first estimated direction."

Next, the estimation unit 3 estimates the direction of arrival of the radio signal based on the second composite signals SS1 to SS4. Using the propagation channel of equation (1), the amplitudes of the plurality of second composite signals SS1 to SS4 input to the estimation unit 3 can be expressed as equations (30) to (33).

|y1a| represents the amplitude of the composite signal SS1 output from the first output terminal O1 of the phase synthesizer 17d. |y2a| represents the amplitude of the composite signal SS2 output from the second output terminal O2 of the phase synthesizer 17d. |y3a| represents the amplitude of the composite signal SS4 output from the second output terminal O2 of the phase synthesizer 17e. |y4a| represents the amplitude of the composite signal SS3 output from the first output terminal O1 of the phase synthesizer 17e. As shown in equations (30) to (33), the way to represent the amplitude of the plurality of first composite signals SS1 to SS4 and the way to represent the amplitude of each composite signal included in the plurality of second composite signals SS1 to SS4 are different. Therefore, the estimation unit 3 can estimate a direction of arrival different from the first estimated direction by calculating the correlation matrix R using equations (30) to (33). Note that a detailed description of the method for determining the correlation matrix R using equations (30) to (33) will be omitted. In the following description, the direction of arrival estimated by the estimation unit 3 based on the second composite signals SS1 to SS4 will be referred to as a "second estimated direction."

The estimation unit 3 estimates the direction of arrival of the radio signal (the direction of the position of the transmitter 4) based on the first estimated direction and the second estimated direction. For example, the estimation unit 3 may estimate the direction of arrival of the radio signal by taking the average of the first estimated direction and the second estimated direction. The estimator 3 of this embodiment estimates the direction of arrival of a radio signal based on a plurality of estimated directions, so compared to existing receiving systems that estimate the direction of arrival of a radio signal based on one estimated direction, The accuracy when estimating the direction of arrival of a signal is improved.

As described above, the receiving system 1 of this embodiment includes the receiver 2 and the estimator 3. The receiver 2 includes a plurality of antennas 11 , a phase combining section 13 , an output section 14 , and a changing section 15 . The plurality of antennas 11 receive radio signals. The changing unit 15 performs a changing process to change at least one element related to the process from receiving the wireless signal to generating the composite signals SS1 to SS4. The phase synthesis unit 13 performs synthesis processing on a plurality of input signals IS1 to IS3 based on radio signals input from a plurality of antennas 11, and estimates the direction of arrival of the radio signals (position direction of the transmitter 4). The composite signals SS1 to SS4 are generated. The phase synthesizer 13 generates first synthesized signals SS1 to SS4 as synthesized signals SS1 to SS4 before the modification process by the changer 15. Furthermore, after the modification process by the modification unit 15, the phase synthesis unit 13 generates second composite signals SS1 to SS4 as composite signals SS1 to SS4. That is, the phase synthesis section 13 generates synthesized signals SS1 to SS4 having different patterns before and after the modification processing by the modification section 15. In other words, the receiver 2 of this embodiment can increase the number of patterns of composite signals SS1 to SS4 for estimating the direction of arrival of radio signals. Then, the output unit 14 outputs the first composite signals SS1 to SS4 and the second composite signals SS1 to SS4 to the estimation unit 3. The estimation unit 3 estimates the direction of arrival of the radio signal based on the first composite signals SS1 to SS4 and the second composite signals SS1 to SS4 output from the output unit 14 of the receiver 2. The estimation unit 3 can estimate the direction of arrival of a radio signal based on two or more patterns of composite signals SS1 to SS4. Therefore, the estimation unit 3 can estimate the direction of arrival of a radio signal based on one pattern of composite signals SS1 to SS4. The accuracy of direction-of-arrival estimation is improved compared to the case where

Moreover, the receiver 2 of this embodiment further includes a switching section 12. The switching unit 12 switches the electrical connection state between the plurality of antennas 11 and the phase combining unit 13. More specifically, the electrical connection state between the antenna 11b and the phase synthesizer 17b is switched from the first connection state to the second connection state, or from the second connection state to the first connection state. The changing unit 15 performs a process of controlling the switching unit 12 to change the electrical connection state between the plurality of antennas 11 and the phase combining unit 13, as at least part of the changing process. By switching the electrical connection state between the plurality of antennas 11 and the phase combining section 13, the receiver 2 can easily increase the number of patterns of composite signals SS1 to SS4 for estimating the direction of arrival of a wireless signal. . Therefore, the receiver 2 can easily improve the accuracy of estimating the direction of arrival of the radio signal.

Furthermore, the phase synthesis section 13 of this embodiment includes a plurality of input sections (input terminals) that are electrically connected to the plurality of antennas 11 and into which wireless signals are input. Specifically, four input terminals: a first input terminal I1 of the phase synthesizer 17a, a first input terminal I1 and a second input terminal I2 of the phase synthesizer 17b, and a second input terminal I2 of the phase synthesizer 17c. It is. The plurality of antennas 11 in this embodiment include three antennas: an antenna 11a, an antenna 11b, and an antenna 11c. That is, the number of multiple antennas 11 in this embodiment is less than or equal to the number of multiple input units. Since the number of antennas 11 is less than the number of input sections, it is possible to make the configuration of the receiver 2 (receiving system 1) compact. Furthermore, by switching the electrical connection state between the plurality of antennas 11 and the input section, the receiver 2 can determine the pattern of the radio signal for estimating the direction of arrival of the radio signal without increasing the number of antennas 11. It can be easily increased. That is, the receiver 2 can improve the accuracy of estimating the direction of arrival of a radio signal without increasing the number of antennas 11. However, even if the number of antennas 11 is greater than the number of input units, the effect of improving the estimation accuracy of the direction of arrival of a radio signal of the receiving system 1 in this embodiment is not lost. . Therefore, the number of antennas 11 of the receiver 2 may be greater than the number of input sections.

(Second embodiment)
(1) Overview An overview of the transmitter 4a and reception system 1a of the second embodiment will be described with reference to FIG. 3. The transmitter 4a of this embodiment includes a plurality of (three in the illustrated example) antennas 21 for transmitting a plurality of wireless signals. The plurality of antennas 21 of this embodiment are array antennas including an antenna 21a, an antenna 21b, and an antenna 21c. In the following description, when describing a specific antenna 21, the antennas 21a, 21b, and 21c will be described separately. In addition, when describing the plurality of antennas 21 without distinguishing them, they are simply referred to as antennas 21.

The receiving system 1a of this embodiment includes a receiving antenna that receives a plurality of wireless signals transmitted from a plurality of antennas 21. The receiving system 1a of this embodiment is a receiving system that estimates the position and direction of a transmitter 4a that has transmitted a plurality of wireless signals based on the received signal strength of a plurality of wireless signals received by a receiving antenna. Consists of.

(2) Configuration of transmitter 4a Hereinafter, the configuration of the transmitter 4a according to the present embodiment will be described with reference to FIG. 4. As shown in FIG. 4, the transmitter 4a includes a plurality of antennas 21, a switching section 22, a phase combining section 23, an original signal generating section 24, and a changing section 25.

The plurality of antennas 21 are electrically connected to the switching section 22. Each of the plurality of antennas 21 transmits a plurality of radio signals RS1 to RS3 generated by the phase synthesizer 23.

The switching unit 22 is a processing unit that is electrically connected between the plurality of antennas 21 and the phase synthesis unit 23 and switches the electrical connection state between the plurality of antennas 21 and the phase synthesis unit 23. The switching unit 22 includes a switch 26a, a switch 26b, and a switch 26c. In the following description, when the switches 26a, 26b, and 26c are described without distinction, they are simply referred to as switch 26. Further, when describing a specific switch 26, the switches 26a, 26b, and 26c will be described separately.

The switching unit 22 performs switching operations of the switches 26a to 26c under the control of the changing unit 25. The switch 26b of the present embodiment, under the control of the changing unit 25, connects the antenna 21b and one of the first output terminal O1 and the second output terminal O2 of the phase synthesizer 27b included in the phase synthesizer 23, Connect electrically. In the following description, the state in which the antenna 21b and the second output terminal O2 of the phase synthesizer 27b are electrically connected by the switch 26b will be referred to as a "first connection state." Further, a state in which the antenna 21b and the first output terminal O1 of the phase synthesizer 27b are electrically connected by the switch 26b will be referred to as a "second connection state."

The switch 26a is controlled so that the antenna 21a and the second output terminal O2 of the phase synthesizer 27a are always electrically connected. That is, the switch 26a of this embodiment does not perform a switching operation. Therefore, the switch 26a may be simply an electrical path connecting the antenna 21a and the second output terminal O2 of the phase synthesizer 27a.

Further, the switch 26c is controlled so that the antenna 21c and the first output terminal O1 of the phase synthesizer 27c are always electrically connected. That is, the switch 26c of this embodiment does not perform a switching operation. Therefore, the switch 26c may be a simple electrical circuit that connects the antenna 21c and the first output terminal O1 of the phase synthesizer 27c.

However, the length of the electrical path from the antenna 21a to the phase synthesizer 27a, the length of the electrical path from the antenna 21b to the phase synthesizer 27b, and the length of the electrical path from the antenna 21c to the phase synthesizer 27c. It is preferable that the lengths are the same. This is because if the lengths of the electrical paths from the antennas 21a to 21c to the phase combiners 27a to 27c are different, the accuracy with which the receiving system 1a estimates the direction of arrival of the radio signal decreases. Therefore, in this embodiment, the switch 26a, the switch 26b, and the switch 26c are configured by the same switch 26.

The original signal generation unit 24 is a processing unit that generates original signals BS1 to BS4, which are the source signals of the plurality of radio signals RS1 to RS3 transmitted by the plurality of antennas 21, and include predetermined information such as identification information, for example. It is. The original signal generation section 24 includes original signal generators 24a to 24d. The original signal generator 24a is electrically connected to the first input terminal I1 of the phase synthesizer 27d of the phase synthesizer 23, and generates the original signal BS1. The original signal generator 24b is electrically connected to the second input terminal I2 of the phase synthesizer 27d, and generates the original signal BS2. The original signal generator 24c is electrically connected to the first input terminal I1 of the phase synthesizer 27e, and generates the original signal BS3. The original signal generator 24d is electrically connected to the second input terminal I2 of the phase synthesizer 27e, and generates the original signal BS4.

The phase synthesis unit 23 is a processing unit that performs synthesis processing on a plurality of input signals IS8 to IS11 (signals IS12 to IS15) based on a plurality of original signals BS1 to BS4, and generates a plurality of radio signals RS1 to RS3. . Furthermore, the phase synthesis unit 23 of this embodiment generates a plurality of different radio signals RS1 to RS3 before and after the switch 26b is switched. Here, in the first connection state, the plurality of radio signals RS1 to RS3 generated by the phase combining section 23 are referred to as the plurality of first radio signals RS1 to RS3. Furthermore, in the second connection state, the plurality of radio signals RS1 to RS3 generated by the phase combining section 23 are referred to as the plurality of second radio signals RS1 to RS3.

The phase synthesizer 23 includes a phase synthesizer 27a, a phase synthesizer 27b, a phase synthesizer 27c, a phase synthesizer 27d, and a phase synthesizer 27e. In the following description, when the phase synthesizers 27a, 27b, 27c, 27d, and 27e are described without distinction, they will simply be referred to as the phase synthesizer 27. The phase synthesizer 27 is composed of, for example, a 90-degree hybrid unit (hybrid element). The basic operation of the phase synthesizer 27 is the same as the basic operation of the phase synthesizer 17 explained in the section "(2.2) Configuration of receiver 2 in (first embodiment)", so the explanation will be omitted. do.

The phase synthesizer 27d receives an input signal IS8 based on the original signal BS1 at a first input terminal I1, and receives an input signal IS9 based on the original signal BS2 at a second input terminal I2. The phase synthesizer 27d generates a signal whose power value is 1/√2 times that of the input signal IS8 and has the same phase, and a signal whose power value is 1/√2 times that of the input signal IS9 and whose phase is delayed by 90 degrees. , is outputted from the first output terminal O1. In addition, the phase synthesizer 27d receives a signal whose power value is 1/√2 times that of the input signal IS8 and whose phase is delayed by 90 degrees, and a signal whose power value is 1/√2 times that of the input signal IS9 and whose phase is delayed by 90 degrees. A signal IS13 which is the sum of the signals and is outputted from the second output terminal O2.

The phase synthesizer 27e receives an input signal IS10 based on the original signal BS3 at a first input terminal I1, and receives an input signal IS11 based on the original signal BS4 at a second input terminal I2. The phase synthesizer 27e generates a signal whose power value is 1/√2 times that of the input signal IS10 and has the same phase, and a signal whose power value is 1/√2 times that of the input signal IS11 and whose phase is delayed by 90 degrees. , is outputted from the first output terminal O1. In addition, the phase synthesizer 27e receives a signal whose power value is 1/√2 times as much as the input signal IS10 and whose phase is delayed by 90 degrees, and a signal whose power value is 1/√2 times as much as the input signal IS11 and whose phase is delayed by 90 degrees. A signal IS15 which is the sum of the signals and is outputted from the second output terminal O2.

The phase synthesizer 27a outputs from the second output terminal O2 a radio signal RS1 which has a power value 1/√2 times that of the signal IS12 input to the second input terminal I2 and has the same phase.

The phase synthesizer 27b receives the signal IS13 at the first input terminal I1, and receives the signal IS14 at the second input terminal I2. In the first connection state, the phase synthesizer 27b receives a signal whose power value is 1/√2 times that of the signal IS13 and whose phase is delayed by 90 degrees, and a signal whose power value is 1/√2 times that of the signal IS14. A radio signal RS2 which is the sum of the same-phase signals and is output from the second output terminal O2. In addition, in the second connection state, the phase synthesizer 27b receives a signal with a power value of 1/√2 times the power value and the same phase as the signal IS13, and a signal with a power value of 1/√2 times the power value of the signal IS14. A radio signal RS2, which is the sum of the signal whose phase is delayed by 90 degrees, is output from the first output terminal O1.

The phase synthesizer 27c outputs, from the first output terminal O1, a radio signal RS3 having a power value 1/√2 times that of the signal IS15 input to the first input terminal I1 and having the same phase.

The changing unit 25 is a processing unit that performs a changing process to change at least one element related to the process from inputting the plurality of original signals BS1 to BS4 to transmitting the plurality of radio signals RS1 to RS3. The changing unit 25 of this embodiment performs a process of controlling the switching unit 22 to change the electrical connection state between the plurality of antennas 21 and the phase combining unit 23, as at least part of the changing process. Specifically, the changing unit 25 switches the electrical connection state between the antenna 21b and the phase synthesizer 27b by controlling the switch 26b to switch. In the following description, it is assumed that the connection state between the antenna 21b and the phase synthesizer 27b is the first connection state until the change unit 25 performs the change process. Further, it is assumed that after the changing unit 25 performs the changing process, the connection state between the antenna 21b and the phase synthesizer 27b is the second connection state. The changing unit 25 performs the changing process at a predetermined timing. The predetermined timing is, for example, the timing at which the phase synthesizer 23 outputs the plurality of radio signals RS1 to RS3, or a certain timing set according to the interval at which the transmitter 4a transmits radio signals.

(3) Estimation of Direction of Arrival Next, a method for the receiving system 1a to estimate the direction of arrival of the plurality of radio signals RS1 to RS3 will be described with reference to FIG. Note that the description of the matters described in the section "(3) Direction of Arrival Estimation in (First Embodiment)" will be omitted as appropriate. As shown in FIG. 3, the complex propagation channel between the antenna 21a and the receiving antenna of the receiving system 1a is h4, the complex propagation channel between the antenna 21b and the receiving antenna is h5, and the complex propagation channel between the antenna 21c and the receiving antenna is h5. Let h6 be the complex propagation channel. Further, the distance between the antenna 21a and the antenna 21b and the distance between the antenna 21b and the antenna 21c are assumed to be d2. Further, it is assumed that the receiving system 1a exists at a position at an angle θ2 with respect to the broadside direction of the array antenna composed of the antenna 21a, the antenna 21b, and the antenna 21c. First, a case will be described in which the receiving system 1a estimates the directions of arrival of the plurality of first radio signals RS1 to RS3.

The propagation channels can be collectively expressed as equation (34).

The correlation matrix of this propagation channel can be expressed as equation (35).

By determining the correlation matrix R, the receiving system 1a can estimate the directions of arrival of the plurality of first radio signals RS1 to RS3. The receiving system 1a determines a correlation matrix R based on information regarding received signal strength.

Using the propagation channel of Equation (34), the amplitudes of the respective original signals BS1, BS2, BS3, and BS4 measured by the receiving system 1a can be expressed as Equations (36) to (39).

It can be expressed as. Here, assuming equation (40), the apparent propagation channel can be expressed as equations (41) to (44).

The method for determining the correlation matrix R based on equations (41) to (44) is the same as described in the section "(3) Direction of Arrival Estimation" in (First Embodiment), so the explanation will be omitted. Furthermore, regarding the method of determining the direction of arrival of the plurality of first radio signals RS1 to RS3 by using a predetermined algorithm such as the MUSIC method on the correlation matrix R, see "(3) Direction of arrival estimation in (first embodiment)". Since it is as explained in the section, the explanation will be omitted. In the following description, the direction of arrival of the plurality of first radio signals RS1 to RS3 estimated by the receiving system 1a will be referred to as a "first estimated direction."

Next, a case will be described in which the receiving system 1a estimates the directions of arrival of the plurality of second radio signals RS1 to RS3. Using the propagation channel of Equation (34), the amplitude of each original signal BS1, BS2, BS3, BS4 measured by the receiving system 1a can be expressed by Equations (45) to (48).

As shown in equations (45) to (48), the amplitude of each original signal BS1, BS2, BS3, and BS4 included in the plurality of first radio signals RS1 to RS3 and the amplitude of each original signal BS1, BS2, BS3, and BS4 included in the plurality of second radio signals RS1 to RS3 are The amplitudes of the respective original signals BS1, BS2, BS3, and BS4 are different. Therefore, the receiving system 1a can estimate a direction of arrival different from the first estimated direction by determining the correlation matrix R using equations (45) to (48). Note that a detailed description of the method for determining the correlation matrix R using equations (45) to (48) will be omitted. In the following description, the direction of arrival of the plurality of second radio signals RS1 to RS3 estimated by the receiving system 1a will be referred to as a "second estimated direction."

The reception system 1a that has received the plurality of first and second radio signals transmitted by the transmitter 4a determines the direction of arrival of the plurality of radio signals RS1 to RS3 (transmitter 4a) based on the first estimated direction and the second estimated direction. (position direction). For example, the receiving system 1a may estimate the directions of arrival of the plurality of radio signals RS1 to RS3 by taking the average of the first estimated direction and the second estimated direction. The receiving system 1a that has received the plurality of first and second radio signals RS1 to RS3 transmitted by the transmitter 4a estimates the directions of arrival of the radio signals RS1 to RS3 based on the plurality of estimated directions. Therefore, compared to existing receiving systems that estimate the directions of arrival of radio signals RS1 to RS3 based on multiple radio signals RS1 to RS3 of one pattern, the accuracy in estimating the directions of arrival of radio signals RS1 to RS3 is lower. improves.

As described above, the transmitter 4a of this embodiment includes the phase combining section 23, a plurality of antennas 21, and the changing section 25. The phase synthesis unit 23 performs a synthesis process on a plurality of input signals IS8 to IS11 (signals IS12 to IS15) based on a plurality of original signals BS1 to BS4, and generates a plurality of radio signals RS1 to RS3. The changing unit 25 performs a changing process to change at least one element related to the process from receiving the plurality of input signals IS8 to IS11 to transmitting the plurality of radio signals RS1 to RS3. The phase synthesis section 23 generates a plurality of first radio signals RS1 to RS3 as a plurality of radio signals RS1 to RS3 before the modification processing by the modification section 25. Furthermore, after the changing process by the changing unit 25, the phase combining unit 23 generates a plurality of second radio signals RS1 to RS3 as the plurality of radio signals RS1 to RS3. The plurality of antennas 21 transmit a plurality of first radio signals RS1 to RS3 and a plurality of second radio signals RS1 to RS3. Since the transmitter 4a transmits a plurality of radio signals RS1 to RS3 in two or more patterns, the receiving system 1a estimates the direction of the transmitter 4a based on the plurality of radio signals RS1 to RS3 in two or more patterns. be able to. Therefore, the estimation accuracy is improved compared to the case where the receiving system 1a estimates the position direction of the transmitter 4a based on one pattern of a plurality of radio signals.

(Modified example)
Below, a receiving system 1 (1a) and a transmitter 4 (4a) according to a modification of the above embodiment are listed. Note that each configuration of the modified example described below can be applied in appropriate combination with each configuration described in the above embodiment.

(1) Modification example 1
In the embodiment described above, the changing unit 15 may perform a process of changing settings related to the time when the plurality of antennas 11 receive wireless signals, as at least part of the changing process. The changing unit 15 changes the time length and reception timing when the plurality of antennas 11 receive radio signals, so that the phase combining unit 13 generates two or more patterns of combined signals SS1 to SS4. That is, by increasing the number of patterns of composite signals SS1 to SS4, the value of |y1| in equation (3), the value of |y2| in equation (4), the value of |y3| in equation (5), and the value of |y3| in equation (6) ) increases in the number of patterns of |y4| values. Therefore, the number of estimation results of the direction of arrival of the unvoiced signal estimated by the receiving system 1 increases, and the estimation accuracy improves.

Furthermore, in the embodiment described above, the changing unit 25 performs a process of changing settings related to the time when the plurality of antennas 21 transmit the plurality of radio signals RS1 to RS3, as at least part of the change processing. You can. By changing the length of time and transmission timing when the plurality of antennas 21 transmit the plurality of radio signals RS1 to RS3, the changing unit 25 allows the transmitter 4a to transmit the plurality of radio signals RS1 to RS3 in two or more patterns. Send. Since the reception system 1a estimates the direction of the transmitter 4a based on the plurality of radio signals RS1 to RS3 of two or more patterns, the accuracy of estimation is improved.

(2) Modification 2
In the above embodiment and modification 1, the phase synthesis unit 13 may perform a process of shifting the phase of at least one of the plurality of input signals IS1 to IS3 (signals IS4 to IS7) in the synthesis process. . Furthermore, as at least part of the changing process, the changing unit 15 may perform a process of changing the amount by which the phase combining unit 13 shifts the phase of the input signals IS1 to IS3 (signals IS4 to IS7) in the combining process. By switching the switch 16b, the receiving system 1 of the embodiment described above allows the input signals IS1 to IS3 (signals IS4 to IS7) to have different phase shifts between the first composite signals SS1 to SS4 and the second composite signals SS1 to SS4. was generating. The changing unit 15 performs a changing process in which the phase combining unit 13 changes the amount by which the phase of the input signals IS1 to IS3 (signals IS4 to IS7) is shifted in the combining process, thereby generating the second combined signal SS1 similar to the above embodiment. It becomes possible to generate ~SS4. Since the reception system 1 estimates the direction of arrival of the radio signal (the direction of the transmitter 4) based on the composite signals SS1 to SS4 of two or more patterns, the accuracy of the estimation is improved.

Furthermore, in the above-described embodiment and modification 1, the phase synthesis unit 23 performs a process of shifting the phase of at least one of the plurality of input signals IS8 to IS11 (signals IS12 to IS15) in the synthesis process. Good too. Furthermore, as at least part of the changing process, the changing unit 25 may perform a process of changing the amount by which the phase combining unit 23 shifts the phases of the input signals IS8 to IS11 (signals IS12 to IS15) in the combining process. By switching the switch 26b, the transmitter 4a of the embodiment described above transmits the input signals IS8 to IS11 (signals IS12 to IS15) with a plurality of first radio signals RS1 to RS3 whose phases are different from each other, and a plurality of second radio signals RS1 to RS3. It was generating radio signals RS1 to RS3. The changing unit 25 performs a changing process of changing the amount by which the phase combining unit 23 shifts the phase of the input signals IS8 to IS11 (signals IS12 to IS15) in the combining process, so that the change unit 25 changes the amount by which the phase combining unit 23 shifts the phase of the input signals IS8 to IS11 (signals IS12 to IS15). It becomes possible to generate radio signals RS1 to RS3. Since the reception system 1a estimates the direction of the transmitter 4a based on the plurality of radio signals RS1 to RS3 of two or more patterns, the accuracy of estimation is improved.

(3) Modification example 3
In the above-described embodiment and modifications 1 and 2, the plurality of antennas 11 may be capable of receiving a plurality of radio signals having mutually different frequency bands as radio signals. For example, when the wireless signal complies with the BLE standard, the plurality of antennas 11 transmits each wireless signal in 40 frequency bands obtained by dividing 2.400 [GHz] to 2.480 [GHz] with a width of 2 [MHz]. It may be possible to receive the information. Then, the changing unit 15 may perform a process of switching the frequency band of the radio signal to be subjected to the combining process, as at least part of the change process. By the changing unit 15 switching the frequency band of the radio signals to be subjected to the combining process, the phase combining unit 13 generates two or more patterns of combined signals SS1 to SS4. Since the reception system 1 estimates the direction of arrival of the radio signal (the direction of the transmitter 4) based on the composite signals SS1 to SS4 of two or more patterns, the accuracy of the estimation is improved.

Furthermore, in the above-described embodiment and modifications 1 and 2, the plurality of antennas 21 may be capable of transmitting a plurality of radio signals RS1 to RS3 having mutually different frequency bands as a plurality of radio signals RS1 to RS3. Then, the changing unit 25 may perform a process of switching the frequency bands of the plurality of radio signals RS1 to RS3 transmitted by the plurality of antennas 21, as at least part of the changing process. Before and after the modification process by the modification unit 25, the plurality of antennas 21 transmit a plurality of radio signals RS1 to RS3 in two or more patterns with mutually different frequency bands. Since the reception system 1a estimates the direction of the transmitter 4a based on the plurality of radio signals RS1 to RS3 of two or more patterns, the accuracy of estimation is improved.

(4) Modification example 4
Further, in the above-described embodiment and modifications 1 to 3, the plurality of antennas 11 may be capable of receiving a plurality of mutually different polarized waves as wireless signals. Here, the plurality of mutually different polarized waves include, for example, horizontally polarized waves, vertically polarized waves, and circularly polarized waves. Then, the changing unit 15 performs a process of switching the polarization type of the radio signal to be subjected to the combining process, as at least part of the change process. The changing unit 15 switches the polarization type of the radio signal to be subjected to the combining process, so that the plurality of antennas 11 receive radio signals having different polarization types. Then, the phase synthesis section 13 generates two or more patterns of synthesized signals SS1 to SS4. Since the receiving system 1 estimates the direction of arrival of the radio signal (the direction of the transmitter 4) based on the composite signals SS1 to SS4 of two or more patterns, the accuracy of the estimation is improved.

Further, in the above embodiment and modifications 1 to 2, the plurality of antennas 21 may be capable of transmitting a plurality of mutually different polarized waves as the plurality of radio signals RS1 to RS3. Then, the changing unit 25 may perform a process of switching the polarization types of the plurality of radio signals RS1 to RS3 transmitted by the plurality of antennas 21 as at least part of the change processing. Before and after the modification process by the modification unit 25, the plurality of antennas 21 transmit a plurality of radio signals RS1 to RS3 in two or more patterns with different polarization types. Since the reception system 1a estimates the direction of the transmitter 4a based on the plurality of radio signals RS1 to RS3 of two or more patterns, the accuracy of estimation is improved.

(5) Other Modifications In this embodiment, the receiver 2 includes the switching unit 12, but the switching unit 12 is not essential. The receiver 2 only needs to include at least a plurality of antennas 11 , a phase combining section 13 , an output section 14 , and a changing section 15 .

Further, in this embodiment, the transmitter 4a includes a switching section 22 and an original signal generation section 24, but the switching section 22 and the original signal generation section 24 are not essential. The transmitter 4a only needs to include at least a plurality of antennas 21, a phase combining section 23, and a changing section 25.

Further, in this embodiment, the receiving system 1 is realized by one system including the receiver 2 and the estimator 3, but it may be realized by two or more systems. For example, the functions of the receiver 2 and the estimator 3 may be distributed and provided in two or more systems. Furthermore, at least one function of the receiver 2 and the estimation unit 3 may be distributed and provided in two or more systems. Furthermore, the functions of the receiver 2 and the estimator 3 may be distributed and provided in a plurality of devices. For example, the functions of the receiver 2 may be distributed and provided in two or more devices. Furthermore, at least some of the functions of the receiving system 1 may be realized by, for example, cloud computing.

(Reception method, program)
The embodiment described above (including each modification example) is only one of various embodiments. The embodiments described above can be modified in various ways depending on the design, etc., as long as the objective of the present disclosure can be achieved. Further, functions similar to those of the receiving system 1 may be realized by a receiving method, a program, a recording medium on which the program is recorded, or the like.

The reception method according to this embodiment includes a reception step, a first phase combination step, a first output step, a change step, a second phase combination step, and a second output step. In the receiving step, a wireless signal is received. In the first phase synthesis step, a synthesis process is performed on a plurality of input signals IS1 to IS3 based on radio signals to generate first synthesized signals SS1 to SS4 for estimating the direction of arrival of the radio signals. In the first output step, the first composite signals SS1 to SS4 generated in the first phase synthesis step are output. In the changing step, at least one element related to the processing from the receiving step to the first phase synthesis step is changed. In the second phase synthesis step, after the changing step, second synthesized signals SS1 to SS4 different from the first synthesized signals SS1 to SS4 generated in the first phase synthesis step are generated. In the second output step, the second composite signals SS1 to SS4 generated in the second phase synthesis step are output.

Further, the (computer) program according to the present embodiment performs one or more of the above-mentioned receiving step, first phase synthesis step, first output step, change step, second phase synthesis step, and second output step. This is a program to be executed by the processor of

The receiver 2, the receiving system 1, the transmitter 4a, and the receiving method include a computer system. A computer system mainly consists of a processor and a memory as hardware. The functions of the receiver 2, the receiving system 1, the transmitter 4a, and the receiving method are realized by the processor executing the program recorded in the memory of the computer system. The program may be pre-recorded in the memory of the computer system. Further, the program may be provided through a telecommunications line, or may be provided recorded on a recording medium readable by a computer system, such as a memory card, an optical disk, or a hard disk drive. A processor in a computer system is comprised of one or more electronic circuits including semiconductor integrated circuits (ICs) or large scale integrated circuits (LSIs). The plurality of electronic circuits may be integrated into one chip, or may be provided in a distributed manner over a plurality of chips. A plurality of chips may be integrated into one device, or may be distributed and provided in a plurality of devices.

(summary)
As is clear from the above embodiments, the present disclosure includes the following first to eleventh aspects. In the following, reference numerals are given in parentheses only to clearly indicate the correspondence with the embodiments.

The receiver (2) according to the first aspect includes a plurality of antennas (11), a phase combining section (13), an output section (14), and a changing section (15). A plurality of antennas (11) receive radio signals. The phase synthesis unit (13) performs synthesis processing on a plurality of input signals (IS1 to IS3) based on radio signals input from a plurality of antennas (11), and performs synthesis processing for estimating the direction of arrival of the radio signals. Generate signals (SS1 to SS4). The output section (14) outputs composite signals (SS1 to SS4). The changing unit (15) performs a changing process to change at least one element related to the process from receiving a wireless signal to generating a composite signal (SS1 to SS4). The phase synthesizer (13) generates first synthesized signals (SS1-SS4) as synthesized signals (SS1-SS4) before the above-mentioned modification process by the changer (15). Further, the phase synthesis section (13) generates second synthesis signals (SS1 to SS4) as the synthesis signals (SS1 to SS4) after the above-mentioned modification processing by the modification section (15). The output section (14) outputs a first composite signal (SS1 to SS4) and a second composite signal (SS1 to SS4).

According to this aspect, the receiver (2) can generate a plurality of composite signals with different patterns by changing at least one element related to processing from receiving a wireless signal to generating composite signals (SS1 to SS4). Generate signals (SS1 to SS4). Since the number of patterns of composite signals (SS1 to SS4) for estimating the direction of arrival of a radio signal (the position direction of the transmitter (4)) can be increased, the accuracy of estimating the direction of arrival of a radio signal can be improved. .

The receiver (2) according to the second aspect further includes a switching section (12) in the first aspect. The switching unit (12) switches the electrical connection state between the plurality of antennas (11) and the phase combining unit (13). The changing unit (15) controls the switching unit (12) to switch the electrical connection state between the plurality of antennas (11) and the phase combining unit (13), as at least part of the changing process. conduct.

According to this aspect, the receiver (2) switches the electrical connection state between the plurality of antennas (11) and the phase synthesizer (13) as part of the change process, thereby allowing the receiver (2) to connect the plurality of antennas with different patterns. Generate composite signals (SS1 to SS4). Since the number of patterns of composite signals (SS1 to SS4) for estimating the direction of arrival of a wireless signal (position direction of the transmitter (4)) can be easily increased, the accuracy of estimating the direction of arrival of a wireless signal can be easily improved. can be done.

In the receiver (2) according to the third aspect, in the first aspect or the second aspect, the phase synthesis section (13) has a plurality of input sections. The plurality of input sections are electrically connected to the plurality of antennas (11) and receive wireless signals. The number of multiple antennas (11) is less than or equal to the number of multiple input units.

According to this aspect, the number of antennas (11) is less than or equal to the number of input sections, so the receiver (2) can be made compact.

A receiver (2) according to a fourth aspect is provided in any one of the first to third aspects, in which the changing unit (15) includes a plurality of antennas (11) as at least part of the changing process. Performs processing to change settings related to the time when receiving silent signals.

According to this aspect, the receiver (2) can generate a plurality of composite signals (SS1 to SS4) with different patterns by changing the settings related to the time (time length, reception timing) when receiving a wireless signal. generate. Since the number of patterns of composite signals (SS1 to SS4) for estimating the direction of arrival of a wireless signal (position direction of the transmitter (4)) can be easily increased, the accuracy of estimating the direction of arrival of a wireless signal can be easily improved. can be done.

In the receiver (2) according to the fifth aspect, in any one of the first to fourth aspects, the phase combining unit (13) selects one of the plurality of input signals (IS1 to IS3) in the combining process. At least one phase shift process is performed. The changing unit (15) performs, as at least part of the changing process, a process of changing the amount by which the phase is shifted in the combining process.

According to this aspect, the receiver (2) generates a plurality of composite signals (SS1 to SS4) with different patterns by changing the amount by which the phase is shifted in the composite processing. That is, it is possible to easily increase the number of patterns of composite signals (SS1 to SS4) for estimating the arrival direction of a radio signal (the position direction of the transmitter (4)). Therefore, the accuracy of estimating the direction of arrival of a radio signal can be easily improved.

In the receiver (2) according to the sixth aspect, in any one of the first to fifth aspects, the plurality of antennas (11) are capable of receiving a plurality of wireless signals having different frequency bands as wireless signals. It is. The changing unit (15) performs, as at least part of the changing process, a process of switching the frequency band of the radio signal to be subjected to the combining process.

According to this aspect, the receiver (2) generates a plurality of synthesized signals (SS1 to SS4) with different patterns by switching the frequency band of the radio signals to be subjected to the synthesis process. That is, it is possible to easily increase the number of patterns of composite signals (SS1 to SS4) for estimating the arrival direction of a radio signal (the position direction of the transmitter (4)). Therefore, the accuracy of estimating the direction of arrival of a radio signal can be easily improved.

In the receiver (2) according to the seventh aspect, in any one of the first to sixth aspects, each of the plurality of antennas (11) is capable of receiving a plurality of mutually different polarized waves as wireless signals. be. The changing unit (15) performs, as at least part of the changing process, a process of switching the type of polarization of the radio signal to be subjected to the combining process.

According to this aspect, the receiver (2) generates a plurality of composite signals (SS1 to SS4) with different patterns by switching the type of polarization of the radio signals to be subjected to the above-mentioned composition processing. That is, it is possible to easily increase the number of patterns of composite signals (SS1 to SS4) for estimating the arrival direction of a radio signal (the position direction of the transmitter (4)). Therefore, the accuracy of estimating the direction of arrival of a radio signal can be easily improved.

Note that the configurations according to the second to seventh aspects are not essential to the receiver (2) and can be omitted as appropriate.

A reception system (1) according to an eighth aspect includes a receiver (2) according to any one of the first to seventh aspects and an estimator (3). The estimator (3) estimates the direction of arrival of the radio signal based on the first composite signal (SS1 to SS4) and the second composite signal (SS1 to SS4) output from the receiver (2).

According to this aspect, the receiving system (1) can generate multiple composite signals with different patterns by changing at least one element related to processing from receiving a wireless signal to generating composite signals (SS1 to SS4). Generate signals (SS1 to SS4). Since the number of patterns of composite signals (SS1 to SS4) for estimating the direction of arrival of a radio signal (the position direction of the transmitter (4)) can be increased, the accuracy of estimating the direction of arrival of a radio signal can be improved. .

The transmitter (4a) according to the ninth aspect includes a phase combining section (23), a plurality of antennas (21), and a changing section (25). The phase synthesis unit (23) performs synthesis processing on a plurality of input signals (IS8 to IS11) based on a plurality of original signals (BS1 to BS4), and generates a plurality of radio signals (RS1 to RS3). The multiple antennas (21) transmit multiple radio signals (RS1 to RS3). The changing unit (25) performs a changing process to change at least one element related to the process from receiving the plurality of original signals (BS1 to BS4) to transmitting the plurality of radio signals (RS1 to RS3). The phase synthesis unit (23) generates a plurality of first radio signals (RS1 to RS3) as a plurality of radio signals (RS1 to RS3) before the modification process by the modification unit (25). Further, the phase synthesis section (23) generates a plurality of second radio signals (RS1 to RS3) as a plurality of radio signals (RS1 to RS3) after the above modification processing by the modification section (25). The plurality of antennas (21) output a plurality of first radio signals (RS1 to RS3) and a plurality of second radio signals (RS1 to RS3).

According to this aspect, the transmitter (4a) changes at least one element related to processing from receiving the plurality of original signals (BS1 to BS4) to transmitting the plurality of radio signals (RS1 to RS3). Then, a plurality of radio signals (RS1 to RS3) with different patterns are transmitted. Since the number of patterns of a plurality of radio signals (RS1 to RS3) can be increased, the accuracy of estimating the position and direction of the transmitter (4a) by the receiving system (1a) can be improved.

The reception method according to the tenth aspect includes a reception step, a first phase combination step, a first output step, a change step, a second phase combination step, and a second output step. In the receiving step, a wireless signal is received. In the first phase synthesis step, a synthesis process is performed on a plurality of input signals (IS1 to IS3) based on radio signals, and a first synthesized signal (SS1 to SS4) is generated for estimating the arrival direction of the radio signal. do. In the first output step, the first synthesized signals (SS1 to SS4) generated in the first phase synthesis step are output. In the changing step, at least one element related to the processing from the receiving step to the first phase synthesis step is changed. In the second phase synthesis step, after the changing step, second synthesized signals (SS1 to SS4) different from the first synthesized signals (SS1 to SS4) generated in the first phase synthesis step are generated. In the second output step, the second composite signals (SS1 to SS4) generated in the second phase synthesis step are output.

According to this aspect, by changing at least one element related to the processing from the reception step to the first phase synthesis step, a plurality of synthesized signals (SS1 to SS4) with different patterns are generated. Since the number of patterns of composite signals (SS1 to SS4) for estimating the direction of arrival of a radio signal (the position direction of the transmitter (4)) can be increased, the accuracy of estimating the direction of arrival of a radio signal can be improved. .

The program according to the eleventh aspect causes one or more processors to execute the receiving method according to the tenth aspect.

According to this aspect, by changing at least one element related to the processing from the reception step to the first phase synthesis step, a plurality of synthesized signals (SS1 to SS4) with different patterns are generated. Since the number of patterns of composite signals (SS1 to SS4) for estimating the direction of arrival of a radio signal (the position direction of the transmitter (4)) can be increased, the accuracy of estimating the direction of arrival of a radio signal can be improved. .

1 Receiving system 2 Receiver 3 Estimating section 4a Transmitter 11 Antenna 12 Switching section 13 Phase combining section 14 Output section 15 Changing section 21 Antenna 22 Switching section 23 Phase combining section 25 Changing section BS1 to BS4 Original signal IS1 to IS3 Input signal IS8 ~IS11 Input signal RS1~RS3 Wireless signal SS1~SS4 Combined signal

Claims (9)

a plurality of antennas for receiving wireless signals;
a phase synthesis unit that performs synthesis processing on a plurality of input signals based on the radio signals input from the plurality of antennas, and generates a composite signal for estimating the direction of arrival of the radio signals;
an output section that outputs the composite signal;
a changing unit that performs a changing process that changes at least one element related to processing from receiving the wireless signal to generating the composite signal;
a switching unit that switches an electrical connection state between the plurality of antennas and the phase combining unit;
Equipped with
The phase synthesis section generates a first composite signal as the composite signal before the modification processing by the modification section, and generates a second composite signal as the composite signal after the modification processing by the modification section. ,
The output unit outputs the first composite signal and the second composite signal,
The phase synthesis section is
comprising a first input section and a second input section that are electrically connected to one of the plurality of antennas via the switching section and into which the wireless signal is input;
performing a process of shifting the phase of at least one of the plurality of input signals in the synthesis process,
The changing unit performs processing for controlling the switching unit to switch the electrical connection state between the plurality of antennas and the phase combining unit, as at least part of the changing process,
The connection state includes a first connection state and a second connection state,
In the first connection state, the one antenna and the second input section are electrically connected via the switching section,
In the second connection state, the one antenna and the first input section are electrically connected via the switching section;
receiver. The phase synthesis section has a plurality of input sections including the first input section and the second input section,
The number of the plurality of antennas is equal to or less than the number of the plurality of input sections,
A receiver according to claim 1. The changing unit performs a process of changing a setting related to a time when the plurality of antennas receive the wireless signal, as at least a part of the changing process.
A receiver according to claim 1 or 2. The plurality of antennas are capable of receiving a plurality of radio signals having mutually different frequency bands as the radio signals,
The changing unit performs a process of switching a frequency band of the wireless signal to be subjected to the combining process, as at least a part of the changing process.
A receiver according to any one of claims 1 to 3. Each of the plurality of antennas is capable of receiving a plurality of mutually different polarized waves as the wireless signal,
The changing unit performs a process of switching the type of polarization of the wireless signal to be subjected to the combining process, as at least part of the changing process.
A receiver according to any one of claims 1 to 4. A receiver according to any one of claims 1 to 5,
an estimator that estimates the direction of arrival of the radio signal based on the first composite signal and the second composite signal output from the receiver;
Equipped with
receiving system. a phase synthesis unit that performs synthesis processing on a plurality of input signals based on a plurality of original signals to generate a plurality of wireless signals;
a plurality of antennas that transmit the plurality of wireless signals;
a changing unit that performs a changing process to change at least one element related to processing from receiving the plurality of original signals to transmitting the plurality of wireless signals;
a switching unit that switches an electrical connection state between the plurality of antennas and the phase combining unit;
Equipped with
The phase synthesis section is
Before the changing process by the changing unit, a plurality of first wireless signals are generated as the plurality of wireless signals, and after the changing process by the changing unit, a plurality of second wireless signals are generated as the plurality of wireless signals. generate,
a first output section and a second output section that are electrically connected to one of the plurality of antennas via the switching section and output the plurality of wireless signals;
The plurality of antennas transmit the plurality of first radio signals and the plurality of second radio signals,
The phase synthesis unit performs a process of shifting the phase of at least one of the plurality of input signals in the synthesis process,
The changing unit performs processing for controlling the switching unit to switch the electrical connection state between the plurality of antennas and the phase combining unit, as at least part of the changing process,
The connection state includes a first connection state and a second connection state,
In the first connection state, the one antenna and the second output section are electrically connected via the switching section,
In the second connection state, the one antenna and the first output section are electrically connected via the switching section;
transmitter. A reception method used in a reception system including a plurality of antennas, a phase synthesis section, and a switching section that switches an electrical connection state between the plurality of antennas and the phase synthesis section, the method comprising:
a receiving step of receiving radio signals at the plurality of antennas;
a first phase combining step in which the phase combining unit performs combining processing on a plurality of input signals based on the wireless signal to generate a first combined signal for estimating the direction of arrival of the wireless signal;
a first output step of outputting the first composite signal generated in the first phase synthesis step;
a changing step of changing at least one element related to the processing from the receiving step to the first phase synthesis step;
After the changing step, a second phase combining step of generating a second combined signal different from the first combined signal generated in the first phase combining step;
a second output step of outputting the second composite signal generated in the second phase synthesis step;
has
The phase combining section has a first input section and a second input section that are electrically connected to one of the plurality of antennas via the switching section and into which the wireless signal is input,
In the first phase synthesis step and the second phase synthesis step, a process of shifting the phase of at least one of the plurality of input signals is performed,
In the changing step, the switching unit is controlled to switch the electrical connection state between the plurality of antennas and the phase combining unit,
The connection state includes a first connection state and a second connection state,
In the first connection state, the one antenna and the second input section are electrically connected via the switching section,
In the second connection state, the one antenna and the first input section are electrically connected via the switching section;
How to receive. A program for causing one or more processors to execute the receiving method according to claim 8.

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