JP2021005780A - Signal processing device and synchronization signal detection method thereof - Google Patents

Abstract

To provide a signal processing device capable of reducing the amount of data required to detect a synchronization signal and reducing the resources used for data retention.SOLUTION: A signal processing device includes: a decimeter 101 that decimates a sampling rate of a received signal according to a condition of a subcarrier interval of the received signal; a matched filter 103 that performs sliding correlation between the decimated received signal and ideal NR-PSS time domain data, and outputs the correlation result; a power calculation unit 105 that calculates correlation power from the correlation result; and a threshold value detection unit 106 that stores the correlation result and timing information at a point at which the correlation power is a predetermined threshold value or more, into a BRAM 107, and detects NR-PSS on the basis of the correlation result stored in the BRAM 107 and the timing information.SELECTED DRAWING: Figure 2

Description

The present invention relates to a signal processing device that processes a received signal to extract information in the signal.

As a signal processing device that processes a received signal and extracts information in the signal, for example, a signal processing device that detects a synchronization signal from the received signal is known.

Such a signal processing device is incorporated in, for example, a radio wave propagation measuring device for measuring a radio wave propagation state of a base station of a mobile communication system, and detects a synchronization signal from the radio wave of the base station.

Patent Document 1 describes a wireless communication system capable of communicating by LTE (Long Term Evolution) or NR (New Radio technology), and describes a synchronization signal included in a radio wave of a base station.

JP-A-2019-4315

According to the LTE standard, the period of the synchronization signal was 5ms, so it was sufficient to hold all the data for 5ms and detect the synchronization signal.

NR-PSS (New Radio-Primary Synchronization Signals), which is a synchronization signal of NR, has a maximum synchronization signal cycle of 160 ms, and in order to retain data during that one cycle, it is at least 160 ms or more. You need to retain the data.

Therefore, an object of the present invention is to provide a signal processing device capable of reducing the amount of data required for detecting a synchronization signal and reducing the resources used for data retention.

The signal processing device of the present invention is a signal processing device that detects a synchronization signal from a received signal, and is a correlation processing unit that performs sliding correlation between the received signal and the ideal data of the synchronization signal and outputs a correlation result. The correlation result and the timing information stored in the correlation result storage unit are provided with the correlation result and the threshold value detection unit for storing the timing information at the point where the correlation result becomes equal to or higher than a predetermined threshold value. The synchronization signal is detected based on the above.

With this configuration, the ideal data of the received signal and the synchronization signal are slid-correlated, the correlation result and timing information of the point where the correlation result is equal to or higher than a predetermined threshold value are stored, and based on the stored correlation result and timing information. The synchronization signal is detected. Therefore, it is not necessary to store the received signals for the maximum period of the synchronization signal, the amount of data required to detect the synchronization signal can be reduced, and the resources used for data retention can be reduced.

Further, in the signal processing apparatus of the present invention, the predetermined threshold value is the average value of the correlation results for a predetermined period.

With this configuration, the average value of the correlation results for a predetermined period is set to a predetermined threshold value. Therefore, the threshold value is determined based on the actual received signal, and the synchronization signal can be detected with high accuracy.

Further, the signal processing apparatus of the present invention includes a decimeter that decimates the sampling rate of the received signal according to the data transfer speed of the received signal and outputs it to the correlation processing unit.

With this configuration, the sampling rate of the received signal is decimate according to the data transfer speed of the received signal and output to the correlation processing unit. Therefore, the resources of the correlation processing unit can be reduced, and the processing load can be reduced.

Further, the synchronization signal detection method of the present invention is a synchronization signal detection method of a signal processing device that detects a synchronization signal from a received signal, and correlates by performing a sliding correlation between the received signal and the ideal data of the synchronization signal. The synchronization signal is detected based on the step of outputting the result, the step of storing the correlation result and the timing information at the point where the correlation result becomes equal to or higher than a predetermined threshold value, and the stored correlation result and the timing information. It is provided with steps to be performed.

With this configuration, the ideal data of the received signal and the synchronization signal are slid-correlated, the correlation result and timing information of the point where the correlation result is equal to or higher than a predetermined threshold value are stored, and based on the stored correlation result and timing information. The synchronization signal is detected. Therefore, it is not necessary to store the received signals for the maximum period of the synchronization signal, the amount of data required to detect the synchronization signal can be reduced, and the resources used for data retention can be reduced.

The present invention can provide a signal processing apparatus capable of reducing the amount of data required to detect a synchronization signal and reducing the resources used for data retention.

FIG. 1 is a block diagram of a radio wave propagation measuring device according to an embodiment of the present invention. FIG. 2 is a block diagram of a radio signal processing unit of the radio wave propagation measuring device according to the embodiment of the present invention. FIG. 3 is a block diagram of a decimeter of the radio signal processing unit of the radio wave propagation measuring device according to the embodiment of the present invention. FIG. 4 is a diagram showing an example of storing ideal NR-PSS time domain data of the radio signal processing unit of the radio wave propagation measuring device according to the embodiment of the present invention. FIG. 5 is a diagram showing an example of the correlation result of the radio signal processing unit of the radio wave propagation measuring device according to the embodiment of the present invention. FIG. 6 is a diagram showing an example of storing the correlation result and timing information of the radio signal processing unit of the radio wave propagation measuring device according to the embodiment of the present invention.

Hereinafter, the signal processing apparatus according to the embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, the radio wave propagation measuring device 1 equipped with the signal processing device according to the embodiment of the present invention includes a radio signal processing unit 10 as a signal processing device, a radio signal measuring unit 11, a user interface unit 12, and a user interface unit 12. It is configured to include a control unit 13.

The radio signal processing unit 10 outputs the radio signal received from the base station 2 via the antenna 16 to the radio signal measuring unit 11 by amplification or frequency conversion.

The radio signal measuring unit 11 is connected to the radio signal processing unit 10 to demodulate and decode the radio signal output by the radio signal processing unit 10, and also SS-RSRP (Synchronization Signal-Reference Signal Received Power) and SS-SIR. (Synchronization Signal-Signal to Interference Ratio), SS-RSRQ (Synchronization Signal-Reference Signal Received Quality), RSSI (Received Signal Strength Indicator), delay profile, etc. are measured, and the measurement results are output to the control unit 13. ing. The control unit 13 stores the measurement result from the wireless signal measurement unit 11 in association with time information and the like in a hard disk or the like, displays and outputs it to the user interface unit 12 at the request of the user, or outputs it to a file as a log. It is designed to do.

The radio signal measuring unit 11 is adapted to input a clock signal from a GPS (Global Positioning System) receiving unit 14 or an internal clock 15. The radio signal measuring unit 11 measures the reception timing of the radio signal based on the PPS (Pulse Per Second: signal having a cycle of 1 second) from the GPS receiving unit 14 or the clock signal from the internal clock 15. The GPS signal may be input from the outside.

The user interface unit 12 includes an input unit 121 that receives an operation input from the user, and a display unit 122 that displays a measurement parameter setting screen and the measurement result of the wireless signal measurement unit 11. The input unit 121 is composed of a touch pad, a keyboard, push buttons, a rotary knob, and the like. The display unit 122 is composed of a liquid crystal display device or the like.

The control unit 13 is composed of a CPU (Central Processing Unit) (not shown), a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk device, and a computer unit including an input / output port.

The ROM and the hard disk device of the computer unit store various control constants, various maps, and the like, as well as a program for causing the computer unit to function as the control unit 13. That is, when the CPU executes the program stored in the ROM and the hard disk device, the computer unit functions as the control unit 13. The hard disk device may be a CF (Compact Flash) card or the like using a flash memory.

A wireless signal measurement unit 11 and a user interface unit 12 are connected to the input / output ports of the control unit 13, and the control unit 13 and each unit can transmit and receive signals.

In the present embodiment, the radio signal measuring unit 11 is composed of a processor such as a DSP (Digital Signal Processor) programmed to execute each process. Further, the wireless signal processing unit 10 is composed of a communication module.

In such a radio wave propagation measuring device 1, for example, the control unit 13 measures the radio signal of the frequency set by the operation input to the input unit 121 with respect to the setting screen displayed on the display unit 122. Let me do it.

The control unit 13 causes the input unit 121 to input the center frequency, frequency bandwidth, number of signals to be measured, and the like of the wireless signal to be measured by the setting screen displayed on the display unit 122. A plurality of center frequencies of the radio signal to be measured can be set.

The control unit 13 notifies the radio signal measurement unit 11 of the setting information input by the input unit 121 to measure the radio signal.

When the control unit 13 notifies the setting information, the radio signal measurement unit 11 notifies the radio signal processing unit 10 of the notified center frequency and frequency bandwidth, and transmits the radio signal of the center frequency and frequency bandwidth. Receive.

When the radio signal processing unit 10 is notified of the center frequency and frequency bandwidth from the radio signal measuring unit 11, the radio signal processing unit 10 receives the radio signal having the center frequency and frequency bandwidth, and performs amplification and frequency conversion to perform the radio signal measuring unit 10. Output to 11.

The radio signal measurement unit 11 demodulates and decodes the radio signal output by the radio signal processing unit 10, measures SS-RSRP, SS-SIR, SS-RSRQ, RSSI, delay profile, etc., and controls the measurement result. Output to unit 13.

Based on the measurement result output by the wireless signal measurement unit 11, the control unit 13 creates an image to be displayed on the display unit 122 according to the measurement result display type selected by the operation input of the input unit 121, and the display unit 122 To display.

In the present embodiment, when measuring the NR radio signal, the radio signal processing unit 10 detects the NR-PSS which is a synchronization signal.

The radio signal processing unit 10 detects NR-PSS by the functional block as shown in FIG.

In FIG. 2, the radio signal processing unit 10 includes a decimeter 101, a FIFO memory 102, a matched filter 103 as a correlation processing unit, a ROM 104, a power calculation unit 105, a threshold value detection unit 106, and a correlation result storage unit. BRAM (Block Random Access Memory) 107 is included in the configuration.

The decimeter 101 is a filter that decimates a received signal having a sampling rate of 30.72 MHz to a sampling rate of 3.84 MHz or 7.68 MHz according to the conditions of the subcarrier interval (SCS: SubCarrier Spacing) of the received signal.

If the subcarrier spacing is 15kHz, the sampling rate is 3.84MHz, if the subcarrier spacing is 30kHz, the sampling rate is 7.68MHz, and if the subcarrier spacing is 120kHz, the sampling rate is 30.72MHz. Is output.

The decimeter 101 is configured, for example, as shown in FIG. In FIG. 3, the decimeter 101 includes a first filter 201, a second filter 202, and a third filter 203.

The first filter 201, the second filter 202, and the third filter 203 are filters that halve the sampling rate of the input signal, respectively.

As shown in FIG. 3, a signal having a subcarrier interval of 15 kHz has a sampling rate of 15.36 MHz by the first filter 201, a sampling rate of 7.68 MHz by the second filter 202, and a sampling rate by the third filter 203. Is set to 3.84MHz and output.

A signal having a subcarrier interval of 30 kHz is output with a sampling rate of 15.36 MHz by the second filter 202 and a sampling rate of 7.68 MHz by the third filter 203.
A signal with a subcarrier interval of 120 kHz is output as it is without passing through a filter.

In FIG. 2, the FIFO memory 102 is a first-in first-out memory. The FIFO memory 102 temporarily stores the signal output by the decimeter 101, and outputs the signal to the matched filter 103 in accordance with the input cycle of the matched filter 103.

The matched filter 103 correlates the input signal with the ideal NR-PSS time domain data stored in the ROM 104, and outputs the correlation result.

The ROM 104 stores three types of ideal NR-PSS time domain data defined in the standard by 3GPP (3rd Generation Partnership Project). For example, as shown in FIG. 4, the ROM 104 stores ideal NR-PSS time domain data.

In FIG. 4, the ROM 104 stores 256 types of IQ data. Each IQ data is 16-bit length data, and 32 bits are used to store one IQ data. Therefore, an area of 32 bits × 256 × 3 = 24576 bits is used.

The matched filter 103 performs a sliding correlation between the desimated data and three types of ideal NR-PSS in a time division manner, and outputs a correlation result.

The power calculation unit 105 calculates the correlation power that can be compared regardless of the sampling rate from the correlation result output by the matched filter 103.

The threshold value detection unit 106 stores the correlation result and the timing information in the BRAM 107 when the correlation power calculated by the power calculation unit 105 becomes equal to or higher than a preset threshold value. The threshold value may be input from the input unit 121 in advance, or for example, the correlation may be taken for a predetermined period and the average value of the resulting correlation power may be used as the threshold value.

For example, when the result of the correlation power as shown in FIG. 5 is obtained, the correlation result and the timing information of the points n, n + 1, m-1, m, and m + 1 at which the correlation power becomes equal to or higher than the threshold value are stored in the BRAM 107.

As shown by A in the figure, points where the timings are continuous are determined to be the same correlation peak. Further, for the non-consecutive points indicated by B and C in the figure, the timing of the point having the highest correlation power is adopted.

As for the result of the correlation power of FIG. 5, for example, as shown in FIG. 6, the correlation result and the timing information are stored in one address of the BRAM 107. 9,600 correlation results and timing information can be stored. 9600 correlation results and timing information can be stored according to the ideal NR-PSS.

In FIG. 6, data in which zero is set in both the correlation result and the timing information, such as the data having the address y, indicates the end of the valid data.

The radio signal processing unit 10 detects NR-PSS from the correlation result and timing information stored in the BRAM 107.

An example of NR-PSS detection processing by the signal processing apparatus according to the present embodiment configured as described above will be described.

The radio signal processing unit 10 calculates the average value of the correlation power in the 5 ms interval in order to determine the threshold value of the correlation power before detecting NR-PSS. At this time, the subcarrier interval is set.

The radio signal processing unit 10 sets the calculated average value of the correlation power as the threshold value of the correlation power.

The radio signal processing unit 10 decimates the received data at a sampling rate of 30.72 MHz with the decimeter 101.

The radio signal processing unit 10 causes the matched filter 103 to perform sliding correlation between the desimated data and three types of ideal NR-PSS in a time-division manner.

The radio signal processing unit 10 causes the power calculation unit 105 to sequentially calculate the correlation power, and stores the correlation result and the timing information of the points at which the correlation power becomes the threshold value or more in the BRAM 107.

The radio signal processing unit 10 reads out the correlation result stored in the BRAM 107, detects the peak, and detects the NR-PSS.

As described above, in the present embodiment, the sliding correlation between the received signal and the time domain data of the ideal NR-PSS is performed, and the correlation result and the timing information at the point where the correlation result becomes equal to or higher than a predetermined threshold value are stored in the BRAM 107. , NR-PSS is detected by detecting the peak from the correlation result stored in the BRAM 107.

As a result, it is not necessary to store the received signal for the maximum cycle of NR-PSS, the amount of data required to detect NR-PSS can be reduced, and the resources used for data retention can be reduced. it can.

Further, the average value of the correlation results for a predetermined period is set as a predetermined threshold value. As a result, the threshold value is determined based on the actual received signal, so that NR-PSS can be detected with high accuracy.

In addition, the sampling rate is decimate according to the conditions of the subcarrier interval of the received signal.

As a result, the resources of the matched filter 103 can be reduced, and the processing load can be reduced.

Although embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

1 Radio wave propagation measuring device 10 Wireless signal processing unit (signal processing device)
101 Decimeter 102 FIFO memory 103 Matched filter (correlation processing unit)
104 ROM
105 Power calculation unit 106 Threshold detection unit 107 BRAM (correlation result storage unit)
201 1st filter 202 2nd filter 203 3rd filter

Claims (4)

A signal processing device (10) that detects a synchronization signal from a received signal.
A correlation processing unit (103) that performs a sliding correlation between the received signal and the ideal data of the synchronization signal and outputs a correlation result,
A threshold value detection unit (106) for storing the correlation result and timing information at a point where the correlation result is equal to or higher than a predetermined threshold value in the correlation result storage unit (107) is provided.
A signal processing device that detects the synchronization signal based on the correlation result and the timing information stored in the correlation result storage unit. The signal processing device according to claim 1, wherein the predetermined threshold value is an average value of the correlation results for a predetermined period. The signal processing apparatus according to claim 1 or 2, further comprising a decimeter (101) that decimates the sampling rate of the received signal according to the data transfer speed of the received signal and outputs it to the correlation processing unit. It is a synchronization signal detection method of the signal processing device (10) that detects a synchronization signal from the received signal.
A step of performing a sliding correlation between the received signal and the ideal data of the synchronization signal and outputting the correlation result.
A step of storing the correlation result and timing information at a point where the correlation result is equal to or higher than a predetermined threshold value.
A synchronization signal detection method comprising a step of detecting the synchronization signal based on the stored correlation result and the timing information.

Images