CN107820273B

CN107820273B - Method and device for detecting synchronization signal of sidelink in D2D

Info

Publication number: CN107820273B
Application number: CN201610824964.7A
Authority: CN
Inventors: 易立强; 李焱
Original assignee: Sanechips Technology Co Ltd
Current assignee: Sanechips Technology Co Ltd
Priority date: 2016-09-14
Filing date: 2016-09-14
Publication date: 2020-05-19
Anticipated expiration: 2036-09-14
Also published as: WO2018049931A1; CN107820273A

Abstract

The invention discloses a method for detecting an auxiliary sidelink synchronization signal in D2D, which comprises the following steps: acquiring a PSSS symbol and an SSSS symbol of a primary sidelink synchronization signal; obtaining adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjusting the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol; and obtaining a sidelink identification SL-ID of the SSSS through detecting the accurate SSSS symbol. The embodiment of the invention also discloses a device for detecting the auxiliary sidelink synchronization signal in the D2D.

Description

Method and device for detecting synchronization signal of sidelink in D2D

Technical Field

The present invention relates to the field of communications, and in particular, to a method and an apparatus for detecting a synchronization signal of sidelink in D2D.

Background

With the rapid development of mobile communication, the communication mode of the conventional cellular network system centering on the base station has a limitation, and the Device-to-Device (D2D) communication mode is receiving an increasing attention. By D2D, it is meant that the traffic data is not forwarded by the base station, but is directly transmitted by the source user equipment to the target user equipment over the air interface, and this communication mode is different from the traditional cellular system communication mode. The D2D technology has short link distance and high channel quality, can meet the information sharing service between adjacent users, and provides transmission service with high speed, low time delay and low power consumption. The D2D heterogeneous network is introduced into the cellular network, so that the network structure can be flexibly expanded, a network blind area can be covered, the cell edge communication quality can be improved by multiplexing cellular network resources, and the user experience and the system capacity can be improved.

In D2D communication, a precondition for data transmission between a source user equipment and a target user equipment is to implement time-frequency synchronization at both transmitting and receiving ends. Unlike the past LTE terminals, the D2D terminals may periodically transmit synchronization signals as synchronization reference sources in partial coverage or no coverage situations, or be indicated by the network as synchronization references for other D2D UEs. Receiving D2D synchronization signals would be more challenging than LTE synchronization. A new Sidelink Sidelink synchronization signal is designed for D2D synchronization in the 3GPP standard protocol. The Sidelink synchronization signal is composed of a Primary Sidelink Synchronization Signal (PSSS) and a Secondary Sidelink Synchronization Signal (SSSS), and is specifically shown in fig. 1. The Sidelink synchronization signal is transmitted on two adjacent Single-carrier Frequency-Division Multiple Access (SC-FDMA) symbols in the same subframe.

SSSS signal detection is one of important steps in synchronization, and is mainly used for detecting a Sidelink identification SL-ID. Because the SSSS design does not adopt the same design method of LTE, the SSSS symbol and the PSSS symbol are far apart, and the channel estimation of the PSSS symbol cannot be utilized to carry out coherent detection to obtain better performance; but only non-coherent detection methods. While SSSS non-coherent detection is sensitive to timing, frequency offset, coherent bandwidth and the like, and the performance is greatly influenced by direct detection. Further, to reduce peak-to-average PAPR, SSSS symbols have a power backoff relative to PSSS symbols, and SSSS detection will be more challenging. Therefore, a technical scheme for detecting the sidelink synchronization signal in D2D is needed to realize the detection of the SSSS in D2D.

Disclosure of Invention

In view of this, embodiments of the present invention are to provide a method and an apparatus for detecting a secondary sidelink synchronization signal in D2D, which can implement accurate detection of an SSSS in D2D.

The technical scheme of the embodiment of the invention is realized as follows:

in one aspect, an embodiment of the present invention provides a method for detecting a secondary sidelink synchronization signal in D2D, where the method includes:

acquiring a PSSS symbol and an SSSS symbol of a primary sidelink synchronization signal; obtaining adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjusting the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol; and obtaining a sidelink identification SL-ID of the SSSS through detecting the accurate SSSS symbol.

In the foregoing solution, the obtaining adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and the obtaining an accurate SSSS symbol by adjusting the SSSS symbol according to the adjustment information includes:

and performing channel impulse response estimation on the PSSS symbol to obtain accurate timing deviation information of the SSSS, and performing timing adjustment on the SSSS symbol according to the accurate timing deviation information to obtain the accurate SSSS symbol.

performing channel impulse response estimation on the PSSS symbol to obtain fine timing offset information and integral frequency offset information of the SSSS; and performing timing adjustment on the SSSS symbol according to the fine timing deviation information, and performing frequency deviation compensation on the SSSS symbol according to the integral multiple frequency deviation information to obtain the precise SSSS symbol.

In the above scheme, the method further comprises:

acquiring fractional frequency offset information; and performing frequency offset compensation on the SSSS symbol according to the fractional frequency offset information.

In the above scheme, the method further comprises:

obtaining a sequence detection value of the PSSS by performing channel impulse response estimation on the PSSS symbol; and determining a set corresponding to the sequence detection value of the PSSS, and determining the SI-ID in the set according to the SSSS group number.

In the foregoing solution, the obtaining the fine timing offset value of the SSSS by performing channel impulse response estimation on the PSSS symbol includes: and carrying out Fourier transform, correlation processing with a PSSS sequence, Fourier inverse transformation, energy calculation, accumulation calculation and peak value search on the PSSS symbol in sequence to obtain a precise timing deviation value of the SSSS.

In the foregoing solution, the obtaining of the sidelink identifier SL-ID of the SSSS by detecting the accurate SSSS symbol includes: and carrying out Fourier transform, correlation processing with an SSSS sequence, energy normalization processing, accumulation calculation and peak value search on the precise SSSS symbol in sequence to obtain the SL-ID of the SSSS.

On the other hand, an embodiment of the present invention further provides an apparatus for detecting a secondary sidelink synchronization signal in D2D, where the apparatus includes: the device comprises an acquisition module, an adjustment module and a determination module; wherein,

the acquisition module is used for acquiring a PSSS symbol and an SSSS symbol of a primary sidelink synchronization signal; the adjusting module is configured to obtain adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjust the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol; and the determining module is used for obtaining the sidelink identification SL-ID of the SSSS through detecting the accurate SSSS symbol.

In the foregoing solution, the adjusting module is specifically configured to: and performing channel impulse response estimation on the PSSS symbol to obtain accurate timing deviation information of the SSSS, and performing timing adjustment on the SSSS symbol according to the accurate timing deviation information to obtain the accurate SSSS symbol.

In the foregoing solution, the adjusting module is specifically configured to: performing channel impulse response estimation on the PSSS symbol to obtain fine timing offset information and integral frequency offset information of the SSSS; and performing timing adjustment on the SSSS symbol according to the fine timing deviation information, and performing frequency deviation compensation on the SSSS symbol according to the integral multiple frequency deviation information to obtain the precise SSSS symbol.

In the above scheme, the apparatus further comprises: a fractional frequency offset module to:

In the foregoing solution, the adjusting module is further configured to:

In the foregoing solution, the obtaining, by the adjusting module, the fine timing offset value of the SSSS by performing channel impulse response estimation on the PSSS symbol includes: and carrying out Fourier transform, correlation processing with a PSSS sequence, Fourier inverse transformation, energy calculation, accumulation calculation and peak value search on the PSSS symbol in sequence to obtain a precise timing deviation value of the SSSS.

In the foregoing solution, the determining module is specifically configured to:

and carrying out Fourier transform, correlation processing with an SSSS sequence, energy normalization processing, accumulation calculation and peak value search on the precise SSSS symbol in sequence to obtain the SL-ID of the SSSS.

The embodiment of the invention provides a method and a device for detecting an auxiliary sidelink synchronization signal in D2D, wherein the method comprises the following steps: acquiring a PSSS symbol and an SSSS symbol of a primary sidelink synchronization signal; obtaining adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjusting the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol; and obtaining a sidelink identification SL-ID of the SSSS through detecting the accurate SSSS symbol. In this way, the PSSS symbol is processed through channel impulse response estimation, the SSSS symbol is adjusted through the acquired adjustment information, and then the SL-ID is detected and determined, so that the SSSS detection performance can be effectively improved.

Drawings

Fig. 1 is a schematic diagram of a structure of a Sidelink synchronization signal;

fig. 2 is a schematic flowchart of a method for detecting a secondary sidelink synchronization signal in D2D according to a first embodiment of the present invention;

fig. 3 is a flowchart illustrating a method for determining SI-ID according to a second embodiment of the present invention;

fig. 4 is a flowchart illustrating a method for detecting a secondary sidelink synchronization signal in D2D according to a third embodiment of the present invention;

fig. 5 is a schematic flowchart of a method for detecting a secondary sidelink synchronization signal in D2D according to a fourth embodiment of the present invention;

fig. 6 is a schematic structural diagram of an apparatus for detecting a secondary sidelink synchronization signal in D2D according to a fifth embodiment of the present invention;

fig. 7 is a schematic structural diagram of another apparatus for detecting a secondary sidelink synchronization signal in D2D according to a fifth embodiment of the present invention.

Detailed Description

The following describes the embodiments in further detail with reference to the accompanying drawings.

Example one

Fig. 2 shows a method for detecting a secondary sidelink synchronization signal in D2D according to an embodiment of the present invention, where the method includes:

s201, acquiring a PSSS symbol and an SSSS symbol of a primary sidelink synchronization signal;

when the source user equipment and the target user equipment carry out D2D communication, firstly, time-frequency synchronization of a transmitting end and a receiving end is carried out, and after one end receives a D2D synchronization signal, the D2D synchronization signal is analyzed by a detection terminal to obtain a PSSS symbol and an SSSS symbol carried in a D2D synchronization signal; the PSSS symbol is a PSSS time domain symbol, and the SSSS symbol is an SSSS time domain symbol.

Here, the detection terminal of the received D2D synchronization signal may be located outside the coverage area or within the coverage area; wherein, the coverage area is the coverage area of the cellular network of the base station (e.g. eNodeB), and the detection terminal of the received D2D synchronization signal may be located within the coverage area of the cellular network of the base station, or may be located outside the coverage area of the cellular network of the base station.

Here, the sidelink IDs include 336, represented by 0-335, where the 336 SIL-IDs are divided into two sets, a first set identified as 0-167, represented by ID _ net, and a second set identified as 168-335, represented by ID _ oon.

The sequence detection value of the PSSS includes two different values, which respectively indicate that the sidelink synchronization signal is located in different sets, specifically, when the PSSS is 0, the SL-ID is indicated to be located in the first set, and the transmission timing reference of the terminal representing the transmission signal is the base station; when the PSSS is 1, it indicates that the SL-ID is in the second set and that the transmit timing reference characterizing the terminal transmitting the signal is not a base station.

S202, obtaining adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjusting the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol;

specifically, the obtaining of the adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and the obtaining of the accurate SSSS symbol by adjusting the SSSS symbol according to the adjustment information include the following cases:

(1) and performing channel impulse response estimation on the PSSS symbol to obtain accurate timing deviation information of the SSSS, and performing timing adjustment on the SSSS symbol according to the accurate timing deviation information to obtain the accurate SSSS symbol.

(2) Performing channel impulse response estimation on the PSSS symbol to obtain fine timing offset information and integral frequency offset information of the SSSS; and performing timing adjustment on the SSSS symbol according to the fine timing deviation information, and performing frequency deviation compensation on the SSSS symbol according to the integral multiple frequency deviation information to obtain the precise SSSS symbol.

After the PSSS symbol is obtained, performing channel impulse response estimation on the PSSS symbol to obtain adjustment information of the SSSS, wherein the adjustment information at least comprises SSSS fine timing deviation information, and also comprises SSSS adjustment information such as integer frequency offset information, PSSS sequence detection value and the like. Here, when performing channel impulse response estimation on the PSSS symbol, the PSSS symbol performing channel impulse response estimation may be the PSSS after performing coarse timing and fractional frequency offset adjustment.

Here, the adjustment information of the SSSS obtained by performing channel impulse response estimation on the PSSS symbol may be different according to a network environment in which the detection terminal is located, specifically, when the detection terminal is a terminal within a coverage area, the obtained adjustment information is SSSS fine timing offset information, and when the detection terminal is a terminal outside the coverage area, the obtained adjustment information may include integer multiple frequency offset information in addition to the SSSS fine timing offset information, and further may include a PSSS sequence detection value.

And in the process of adjusting the SSSS to obtain the accurate SSSS symbol, correspondingly adjusting the obtained SSSS symbol according to different obtained adjustment information.

When SSSS adjustment information obtained after PSSS symbol is subjected to channel impulse response estimation is fine timing deviation information, the obtained fine timing deviation information is utilized to perform timing adjustment on the SSSS symbol; here, when performing timing adjustment, the adjusted SSSS symbol may be an SSSS symbol acquired by using coarse timing.

And when the SSSS adjustment information obtained after the PSSS symbol is subjected to channel impulse response estimation comprises integer frequency offset information, performing frequency offset compensation on the SSSS symbol by using the obtained integer frequency offset information to obtain the accurate SSSS symbol.

Here, the obtaining the fine timing offset value for the SSSS by performing channel impulse response estimation on the PSSS symbol includes: and carrying out Fourier transform, correlation processing with a PSSS sequence, Fourier inverse transformation, energy calculation, accumulation calculation and peak value search on the PSSS symbol in sequence to obtain a precise timing deviation value of the SSSS. Wherein, the PSSS sequence is a PSSS sequence indicated by a ZC (Zadoff-Chu) code root.

When performing frequency offset compensation on the SSSS symbol, the method further includes: acquiring fractional frequency offset information; and performing frequency offset compensation on the SSSS symbol according to the fractional frequency offset information. Here, the frequency offset compensation performed on the SSSS includes frequency offset compensation of integer frequency offset information and frequency offset compensation of fractional frequency offset information.

S203, obtaining a sidelink identification SL-ID of the SSSS through detecting the accurate SSSS symbol.

Detecting the SL-ID of the SSSS when the precise SSSS symbol is obtained, wherein the obtaining of the sidelink identification SL-ID of the SSSS through the detection of the precise SSSS symbol comprises: and carrying out Fourier transform, correlation processing with an SSSS sequence, energy normalization processing, accumulation calculation and peak value search on the precise SSSS symbol in sequence to obtain the SL-ID of the SSSS.

The method further comprises the following steps: obtaining a sequence detection value of the PSSS by performing channel impulse response estimation on the PSSS symbol; and determining a set corresponding to the sequence detection value of the PSSS, and determining the SI-ID in the set according to the SSSS group number. And the SSSS group number is a numerical value obtained by sequentially carrying out Fourier transform, correlation processing with an SSSS sequence, energy normalization processing, accumulation calculation and peak value search on the accurate SSSS symbol.

Here, the sequence detection value of the PSSS can represent whether the SL-ID of the SSSS received by the current detection terminal belongs to the first set or the second set, and when the PSSS sequence detection value indicates that the SL-ID is located in the first set, the position corresponding to the SSSS group number in the first set is the currently detected SL-ID; and when the PSSS sequence detection value indicates that the SL-ID is located in the second set, the position corresponding to the SSSS group number in the second set is the currently detected SL-ID.

And after the sequence detection value of the PSSS is obtained by performing channel impulse response estimation on the PSSS symbol, performing relevant processing on the SSSS symbol and the SSSS sequence in the process of determining the SL-ID according to the accurate SSSS symbol, and determining the SSSS sequence by using the sequence detection value of the PSSS obtained by performing channel impulse response estimation on the PSSS symbol. Here, when determining the SSSS sequence to be subjected to the correlation process, the sequence detection value of the PSSS obtained by performing channel impulse response estimation on the PSSS symbol may be used, or the sequence detection value of the PSSS determined by another method may be used, which is not limited in the embodiment of the present invention.

Here, when the detection terminal is located in the coverage area, the SSSS group number obtained after the peak search is the SL-ID. And when the detection terminal is positioned outside the coverage range, determining the SL-ID according to the SSSS group number obtained after the peak value search and the sequence detection value of the PSSS.

In practical use, when the detection terminal is located near the edge of the network coverage, it may receive signals from the transmission terminal that directly or indirectly uses the base station as the transmission timing reference, or may receive signals from the transmission terminal outside the coverage that does not use the base station as the transmission timing reference. The detecting terminal may select the synchronization source according to a priority level prescribed by a protocol, for example, a transmitting terminal directly or indirectly having the base station as a transmission timing reference has a higher priority than a transmitting terminal not having the base station as a transmission timing reference.

Example two

In the embodiment of the present invention, a method for detecting SL-ID in the SSSS in D2D is described, as shown in fig. 3, the method includes:

s301, performing channel impulse response estimation by the acquired PSSS symbol to obtain fine timing deviation information of the SSSS symbol;

s302, correlation detection is carried out on SSSS symbols of which the timing is adjusted to obtain SL-IDs.

Here, for the detecting terminal, regardless of whether the detecting terminal is in the coverage area or out of the coverage area, fine timing offset information of the SSSS is obtained by performing channel impulse response estimation on the PSSS, after the fine timing offset information is obtained, fine timing adjustment is performed on the obtained SSSS symbol by the fine timing offset information, an adjusted SSSS symbol is obtained, and the SL-ID is determined by performing correlation detection on the SSSS.

When the detection terminal is out of the coverage range, the PSSS sequence detection value and the integral multiple frequency offset information are obtained while the fine timing offset information of the SSSS is obtained by performing channel impulse response estimation on the PSSS; the SSSS symbol is adjusted by taking the fine timing deviation information, the PSSS sequence detection value and the integral multiple frequency deviation information as adjustment information to obtain an accurate SSSS symbol and an accurate SSSS sequence, so that an accurate SL-ID is obtained through the related detection of the SSSS symbol, a detection terminal can finish the identification of a timing reference terminal for sending signals, and data synchronization is carried out.

EXAMPLE III

In the embodiment of the present invention, the method for detecting the SSSS in D2D provided in the embodiment of the present invention is further described in a specific application scenario in which the detection terminal is located outside the coverage area, where in this case, the processing step of SSSS detection is shown in fig. 4, and specifically includes:

s401, performing channel impulse response estimation through the obtained PSSS symbol to obtain the fine timing of the SSSS symbol, the PSSS sequence detection value and the integer frequency offset information. The method specifically comprises the following steps:

(1) acquiring a PSSS symbol;

here, the PSSS symbols are acquired before channel impulse response estimation is performed on the PSSS symbols. The acquired PSSS symbols are PSSS signals that have undergone coarse timing adjustment and fractional offset compensation, and the coarse timing and fractional offset information may be provided by a pre-stage module that may perform PSSS autocorrelation processing, but is not limited to such.

Here, the obtained PSSS symbol is represented by y_PSSS,i(n), i is 0, 1; n-1 denotes, i is indicated by PSSS symbol, and N is 128.

(2) Removing the frequency shift of 1/2 subcarrier frequency;

removing a half subcarrier frequency shift Δ f/2 from the PSSS signal, Δ f being the subcarrier frequency spacing:

y′_PSSS,i(n)＝y_PSSS,i(n)·e^-jπn/Ni＝0,1；n＝0,1,...,N-1。

(3)FFT；

converting the time domain signal to the frequency domain to obtain

(4) Correlation processing with PSSS sequences;

after the conversion from time domain to frequency domain, the false subcarrier is removed to obtain Y_PSSS,i(k) And k is a subcarrier index. If X_uPSSS sequence representing ZC (Zadoff-Chu) code root indication, u 26,37, for Y_PSSS,i(k) And (3) performing cyclic conjugate multiplication processing of cyclic shift s:

wherein (·)_NDenotes a cyclic shift with a period of N, and b denotes a maximum integer multiple value of the frequency offset to be estimated with respect to the subcarrier spacing.

(5)IFFT；

After conjugate multiplication with PSSS sequence, C is processed by IFFT_u,sConverting to time domain, obtaining channel impulse response,

(6) calculating energy;

concentrating channel impulse response on the found h_u,s(n) within a shorter interval, obtaining a channel impulse response region [ -L ]₂,L₁]Value, and energy is obtained to obtain | h_u,s(n)|²。

(7) Performing accumulation calculation;

accumulating the energy calculation values among symbols, among antennas and the transmission period of the Sidelink synchronous signal to obtain the value

i, P, Q denote symbol indication, antenna indication and accumulation period indication, respectively, and P, Q denote the number of antennas and the number of accumulation periods, respectively.

(8) Searching a peak value;

the peak value search is carried out on the accumulated area energy value of 2b +1 integer frequency deviation values under 2 PSSS sequences, and the [ -L ] where the peak value is searched₂,L₁]Obtaining a fine timing deviation value delta tau at the internal position, searching a PSSS sequence used by the peak value correspondingly to obtain a PSSS sequence detection value u, and searching an integral multiple frequency deviation value where the peak value correspondingly is to obtain an integral multiple frequency deviation value s

In the formula, i, P, Q represent a sign indication, an antenna indication, and an accumulation period indication, respectively, and P, Q represent the number of antennas and the number of accumulation periods, respectively.

The CP pattern used by the fine timing offset value Δ τ and D2D corresponds to the PSSS and SSSS sample distances, and a fine timing position of the SSSS symbol can be obtained. The detected integral multiple frequency offset is s · Δ f.

S402, obtaining SL-ID by carrying out correlation detection on SSSS symbols after timing adjustment and frequency offset compensation.

(1) Acquiring SSSS symbols;

the SSSS symbol is adjusted according to the detected fine timing deviation information of the SSSS, and frequency deviation compensation is performed by using the detected frequency deviation information, wherein the frequency deviation compensation comprises integer frequency deviation compensation of integer frequency deviation information and fractional frequency deviation compensation of initially estimated fractional frequency deviation provided by a front module.

Assume acquired SSSS symbol y_SSSS,i(n), i is 0, 1; n-1 denotes, i is indicated by the SSSS symbol, and N-128.

(2) Removing the frequency shift of 1/2 subcarrier frequency;

removing a half subcarrier frequency shift Δ f/2 for SSSS signals, Δ f being the subcarrier frequency spacing

y′_SSSS,i(n)＝y_SSSS,i(n)·e^-jπn/Ni＝0,1；n＝0,1,...,N-1。

(3)FFT；

Converting the time domain signal to the frequency domain to obtain

(4) Processing related to the SSSS sequence;

after the conversion from time domain to frequency domain, the false subcarrier is removed to obtain Y_SSSS,i(k) And k is a subcarrier index. The SSSS-related detection may be non-coherent detection or differential detection, but is not limited thereto. In the following, the incoherent detection method is taken as an example, if X_vAnd representing a v-th group of SSSS codes, wherein v is 0,1, 167, and the obtained frequency domain SSSS and SSSS local codes are subjected to segment correlation, namely the SSSS local codes are divided into M segments, and each segment is subjected to correlation processing respectively.

(5) Energy normalization processing;

and the frequency domain SSSS symbol energy normalization processing is carried out on the correlation value energy value, so that the influence of SSSS symbol power backoff on the SSSS detection performance can be avoided.

(6) Performing accumulation calculation;

completing the accumulation among symbols, among antennas and the transmission period of the Sidelink synchronous signals:

wherein M represents the related segmentation indication, M represents the number of segments, and B represents the length of the segments; i, P, Q denote symbol indication, antenna indication and accumulation period indication, respectively, and P, Q denote the number of antennas and the number of accumulation periods, respectively.

(7) Peak search

The peak value searching is carried out on the result after the accumulation calculation to obtain the SSSS group number,

further SL-ID is available, i.e

At the out-of-coverage D2D terminals, the initial frequency offset may be up to ± 10PPM, perhaps up to 20PPM relative to the terminals transmitting the D2D signal, since they are not substantially synchronized with the network. Under the condition of removing the fractional frequency offset, integral frequency offset may still exist, so that the SSSS detection fails. In addition, the SSSS non-coherent detection is very sensitive to timing, and the performance is rapidly deteriorated due to the extremely small deviation of timing sampling points, so that the system requirements are difficult to meet. The SSSS detection method provided by the embodiment of the invention utilizes the PSSS symbol to carry out channel impulse response estimation, accurately obtains timing deviation and integral multiple frequency offset, and further adjusts and compensates the SSSS symbol, thereby improving the detection success rate of the SSSS.

Example four

In the embodiment of the present invention, the method for detecting the SSSS in D2D provided in the embodiment of the present invention is further described in a specific application scenario where the detection terminal is located in the coverage area. Here, the D2D terminal has acquired frequency synchronization with the network within the coverage area, and has a small influence on the D2D reception. In this case, the processing steps of SSSS detection are as shown in fig. 5, and specifically include:

and S501, performing channel impulse response estimation through the acquired PSSS symbol to obtain the fine timing of the SSSS symbol. The process is as follows:

(1) acquiring a PSSS symbol;

the PSSS symbols are obtained according to the coarse timing provided by the front-end module, and the terminals outside the coverage range. The pre-module may be, but is not limited to, a PSSS cross-correlation process.

Here, the obtained PSSS symbol is represented by y_PSSS,i(n), i is 0, 1; n-1 denotes, i is indicated by PSSS symbol, and N is 128. Since the frequency synchronization is basically obtained, the symbols in the time domain can be subjected to the accumulation average processing

(2) Removing the frequency shift of 1/2 subcarrier frequency;

removing half of the subcarrier frequency shift Δ f/2, Δ f being the subcarrier frequency spacing

y′_PSSS(n)＝y_PSSS(n)·e^-jπn/Nn＝0,1,...,N-1

(3)FFT；

Converting the time domain signal to the frequency domain to obtain

(4) Correlation processing with PSSS sequences;

after the conversion from time domain to frequency domain, the false subcarrier is removed to obtain Y_PSSS(k) And k is a subcarrier index. If it is

Representing the local PSSS code indicated by ZC code root detected by the PSSS sequence of the front module, for Y_PSSS(k) Performing conjugate multiplication processing

(5)IFFT；

Proceed with PSSS sequenceAfter the correlation processing of the columns, the IFFT will be performed

Converting to time domain, obtaining channel impulse response,

(6) calculating energy;

with channel impulse response centred on

Within a shorter interval, obtaining a channel impulse response region [ -L ]₂,L₁]Value, finding the energy to obtain

(7) Performing accumulation calculation;

accumulating the sum of the antenna and the transmission period of the Sidelink synchronous signal to obtain

(8) Searching a peak value;

performing peak search to obtain fine timing deviation value delta tau

In the formula, P, Q represent an antenna indication and an accumulation period indication, respectively, and P, Q represent the number of antennas and the number of accumulation periods, respectively. The CP pattern used by the fine timing offset value Δ τ and D2D corresponds to the PSSS and SSSS sample distances, and a fine timing position of the SSSS symbol can be obtained.

S502, obtaining SL-ID by carrying out correlation detection on the SSSS symbol after timing adjustment.

(1) Acquiring SSSS symbols;

and the SSSS symbol is obtained after fine timing adjustment is carried out according to the detected fine timing deviation information.

Assume acquired time domain SSSS symbol is y_SSSS,i(n), i is 0, 1; n-1 denotes, i is indicated by the SSSS symbol, and N-128. The symbols in the time domain can be subjected to accumulation average processing

(2) Removing the frequency shift of 1/2 subcarrier frequency;

y′_SSSS(n)＝y_SSSS(n)·e^-jπn/Nn＝0,1,....,N-1。

(3)FFT；

Converting the time domain signal to the frequency domain to obtain

(4) Processing related to the SSSS sequence;

after the conversion from time domain to frequency domain, the false subcarrier is removed to obtain Y_SSSS(k) And k is a subcarrier index. The SSSS-related detection may be non-coherent detection or differential detection, but is not limited thereto. Following the non-coherent detection method, if X_vA v-th set of SSSS codes is denoted, where v-0, 1.

(5) Energy normalization processing;

(6) Performing accumulation calculation;

wherein M represents the related segmentation indication, M represents the number of segments, and B represents the length of the segments; p, Q denote an antenna indication and an accumulation period indication, respectively, and P, Q denote the number of antennas and the number of accumulation periods, respectively.

(7) Searching a peak value;

a peak search is performed to obtain the SSSS group number,

because the detecting terminal is located in the coverage area, the detecting terminal can select to receive the transmitting terminal signal with higher priority and using the base station as the transmitting timing reference, so as to obtain SL-ID of

It should be noted that, in the embodiment of the present invention, when the detection terminal is located outside the coverage, the PSSS sequence detection information may use information known in the prior art in advance, or may use PSSS sequence detection information obtained by performing channel impulse response estimation on a PSSS symbol. For example: in the method shown in fig. 4, PSSS sequence detection information obtained by performing channel impulse response estimation on PSSS symbols is used. When the terminal is located in the coverage area, as shown in fig. 5, the PSSS sequence detection information may be obtained by other methods, and the PSSS sequence detection information is considered to be obtained in advance when the SSSS detection is performed.

EXAMPLE five

In order to implement the method for detecting the SSSS in D2D, an embodiment of the present invention further provides a device for detecting the SSSS in D2D. As shown in fig. 6, the apparatus includes: an acquisition module 601, an adjustment module 602, and a determination module 603; wherein,

an obtaining module 601, configured to obtain a primary sidelink synchronization signal PSSS symbol and a secondary sidelink synchronization signal SSSS symbol;

an adjusting module 602, configured to obtain adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjust the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol;

wherein the adjusting module 602 obtains the fine timing offset value of the SSSS by performing channel impulse response estimation on the PSSS symbol includes: and carrying out Fourier transform, correlation processing with a PSSS sequence, Fourier inverse transformation, energy calculation, accumulation calculation and peak value search on the PSSS symbol in sequence to obtain a precise timing deviation value of the SSSS.

A determining module 603, configured to obtain a sidelink identifier SL-ID of the SSSS through detection of the accurate SSSS symbol.

The determining module 603 is specifically configured to: and carrying out Fourier transform, correlation processing with an SSSS sequence, energy normalization processing, accumulation calculation and peak value search on the precise SSSS symbol in sequence to obtain the SL-ID of the SSSS.

Here, the adjusting module 602 may be specifically configured to: and performing channel impulse response estimation on the PSSS symbol to obtain accurate timing deviation information of the SSSS, and performing timing adjustment on the SSSS symbol according to the accurate timing deviation information to obtain the accurate SSSS symbol.

The adjustment module 602 may be specifically configured to: performing channel impulse response estimation on the PSSS symbol to obtain fine timing offset information and integral frequency offset information of the SSSS; and performing timing adjustment on the SSSS symbol according to the fine timing deviation information, and performing frequency deviation compensation on the SSSS symbol according to the integral multiple frequency deviation information to obtain the precise SSSS symbol.

The adjustment module 602 is further configured to: obtaining a sequence detection value of the PSSS by performing channel impulse response estimation on the PSSS symbol; correspondingly, the determining module 603 is configured to determine a set corresponding to the sequence detection value of the PSSS, and determine the SI-ID in the set according to the SSSS group number.

As shown in fig. 7, the apparatus further includes: a fractional frequency offset module 604 for: acquiring fractional frequency offset information; and performing frequency offset compensation on the SSSS symbol according to the fractional frequency offset information.

In this embodiment of the present invention, the apparatus for detecting SSSS in D2D provided in this embodiment of the present invention may be implemented by a processor and a memory, where the memory has computer executable instructions; the processor is configured to perform the following operations in accordance with the computer-executable instructions: acquiring a PSSS symbol and an SSSS symbol of a primary sidelink synchronization signal; obtaining adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjusting the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol; obtaining a sidelink identification SL-ID of the SSSS by detecting the precise SSSS symbol

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.

Claims

1. A method for detecting a secondary sidelink synchronization signal in D2D, the method comprising:

acquiring a PSSS symbol and an SSSS symbol of a primary sidelink synchronization signal;

obtaining adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjusting the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol; wherein the adjustment information of the SSSS at least comprises fine timing offset information of the SSSS;

and obtaining a sidelink identification SL-ID of the SSSS through detecting the accurate SSSS symbol.

2. The method of claim 1, wherein obtaining adjustment information for the SSSS by performing channel impulse response estimation on the PSSS symbols, and wherein adjusting the SSSS symbols according to the adjustment information to obtain precise SSSS symbols comprises:

3. The method of claim 1, wherein obtaining adjustment information for the SSSS by performing channel impulse response estimation on the PSSS symbols, and wherein adjusting the SSSS symbols according to the adjustment information to obtain precise SSSS symbols comprises:

performing channel impulse response estimation on the PSSS symbol to obtain fine timing offset information and integral frequency offset information of the SSSS;

and performing timing adjustment on the SSSS symbol according to the fine timing deviation information, and performing frequency deviation compensation on the SSSS symbol according to the integral multiple frequency deviation information to obtain the precise SSSS symbol.

4. The method of claim 3, further comprising:

acquiring fractional frequency offset information;

and performing frequency offset compensation on the SSSS symbol according to the fractional frequency offset information.

5. The method of claim 1, further comprising:

obtaining a sequence detection value of the PSSS by performing channel impulse response estimation on the PSSS symbol;

and determining a set corresponding to the sequence detection value of the PSSS, and determining the SL-ID in the set according to the SSSS group number.

6. The method of claim 2, wherein obtaining the fine timing offset value for the SSSS by channel impulse response estimation on the PSSS symbols comprises:

and carrying out Fourier transform, correlation processing with a PSSS sequence, Fourier inverse transformation, energy calculation, accumulation calculation and peak value search on the PSSS symbol in sequence to obtain a precise timing deviation value of the SSSS.

7. The method of claim 1, wherein obtaining a sidelink identification (SL-ID) of SSSS through detection of the precise SSSS symbol comprises:

8. An apparatus for detecting a secondary sidelink synchronization signal in D2D, the apparatus comprising: the device comprises an acquisition module, an adjustment module and a determination module; wherein,

the acquisition module is used for acquiring a PSSS symbol and an SSSS symbol of a primary sidelink synchronization signal;

the adjusting module is configured to obtain adjustment information of the SSSS by performing channel impulse response estimation on the PSSS symbol, and adjust the SSSS symbol according to the adjustment information to obtain an accurate SSSS symbol; wherein the adjustment information of the SSSS at least comprises fine timing offset information of the SSSS;

and the determining module is used for obtaining the sidelink identification SL-ID of the SSSS through detecting the accurate SSSS symbol.

9. The apparatus of claim 8, wherein the adjustment module is specifically configured to:

10. The apparatus of claim 8, wherein the adjustment module is specifically configured to:

11. The apparatus of claim 10, further comprising: a fractional frequency offset module to:

acquiring fractional frequency offset information;

12. The apparatus of claim 8, wherein the adjustment module is further configured to:

13. The apparatus of claim 9, wherein the means for adjusting obtains the fine timing offset value for the SSSS by performing a channel impulse response estimation on the PSSS symbols comprises:

14. The apparatus of claim 8, wherein the determining module is specifically configured to: