WO2016070687A1

WO2016070687A1 - Synchronization estimation method and receiving end device

Info

Publication number: WO2016070687A1
Application number: PCT/CN2015/090385
Authority: WO
Inventors: 刘刚; 周海军
Original assignee: 电信科学技术研究院
Priority date: 2014-11-04
Filing date: 2015-09-23
Publication date: 2016-05-12
Also published as: CN105635002A; TW201618474A; CN105635002B; TWI587642B

Abstract

Disclosed are a synchronization estimation method and a receiving end device, which are used for solving the problems of poor performance and relatively high noise of the existing synchronization estimation, and low accuracy and relatively high noise of the existing frequency offset estimation method. The method comprises: receiving a data sequence containing a preamble; and according to a long preamble in the preamble, conducting timing estimation and/or frequency offset estimation, so as to realize synchronization with a sending end, wherein the long preamble comprises a prefix, a long sequence and a suffix in sequence, wherein a sequence in the prefix is the same as a sequence in the long sequence which is separated from the prefix at a first set distance, and a sequence in the suffix is the same as a sequence in the long sequence which is separated from the suffix at a second set distance.

Description

Synchronous estimation method and receiving end device

Cross-reference to related applications

The present application claims priority to Chinese Patent Application No. 201410613030.X filed on Nov. 4, 2014, the entire content of which is hereby incorporated by reference.

Technical field

The present disclosure relates to the field of communications technologies, and in particular, to a synchronization estimation method and a receiving end device.

Background technique

At present, the commonly used channel structure is shown in FIG. 1 , and the preamble (Preamble) is used for automatic gain control (AGC), synchronization, and frequency offset estimation. The preamble usually includes a short preamble and a long preamble. The short preamble can be used to roughly determine the reception time of the long preamble, and the interception of a long preamble for time domain correlation can estimate the exact time of the received signal. In the preamble, the short preamble and the long preamble occupy the same frequency band. Figure 2 shows a schematic diagram of the frame structure of 802.11p, in which the first 10 symbols (t1~t10) are short preambles, GI2 is a cyclic prefix of long preambles, and the last two symbols (T1 and T2) are long preambles. The code, GI is the cyclic prefix of the data symbol. The SIGNAL field is the physical layer control channel, and the DATA field is the high layer signaling and data.

Under the above frame structure, symbol timing estimation (ie, estimating the starting position of the preamble, such as the starting position of the short preamble or the starting position of the long preamble), and starting from the preamble of the symbol timing estimation may be implemented. The starting position estimates a range of frequency offsets. Wherein, the symbol timing further includes Two processes of coarse synchronization and fine synchronization.

1. Rough synchronization: Using the multiple repeated short preamble sequences defined above, the autocorrelation algorithm is used to quickly obtain coarse time synchronization. In order to overcome the "platform" phenomenon appearing in the correlation value (the so-called platform phenomenon means that the correlation value distribution is relatively flat and it is difficult to find obvious peaks), in order to improve the estimation accuracy, two autocorrelation value sequences need to be calculated. The first correlation value sequence M ₁ (θ) is a conjugate correlation of the received signal with a sequence of its own short delay preamble symbol length, the correlation length N _s =16; the second correlation value sequence M ₂ (θ) is The received signal is related to the conjugate of its own short delay sequence of 2 short preamble symbols, and the correlation length is 2N _s . Calculate M ₁ (θ)-M ₂ (θ) according to the following formula to get the result of coarse synchronization

The peak value is the start time of the ninth short preamble symbol.

Where θ represents the start time of the synchronization estimation, r(θ) represents the received signal sequence, m represents the position relative to the start time, and r ^* () represents the conjugate operation of the received sequence.

Second, fine synchronization: using the two repeated long preamble sequences in the frame structure, determined in the coarse synchronization The approximate location uses the autocorrelation algorithm to obtain fine synchronization.

The frequency offset estimation also includes coarse frequency offset estimation and fine frequency offset estimation. It is assumed that the preamble sequence is repeated by the basic code of length N _x , the transmission sequence is Plcp(i), and the reception sequence is r(i), which can be approximated as r(i)=a·Plcp(i)· Exp(j·2π·f _d ·i·T _S )+n(i), where a is the complex gain brought by the channel, f _d is the Doppler shift, n(i) is the noise, and there is Plcp ( i) = plcp(i+k·N _x ), where k is an integer. From the perspective of implementation simplicity, the time domain signal can be directly used to find the frequency offset value. details as follows:

r(i+k·N _x )·(r(i)) ^* =|a·Plcp(i)| ² exp(j·2π·f _d ·k·N _x ·T _S )+n′′;

Where n''=(n(i))*·r(i+k·N _x )+(r(i)-n(i)) ^* ·n(i+k·N _x ).

Further, let d(i)=r(i+k·N _x )·(r(i)) ^* , and the multiple values of d(i) can reduce the influence of noise and improve the accuracy of frequency offset estimation. which is

Let f _Δ = θ _Δ /(k·N _x ·T _S ) be the frequency offset estimation error. Among them, mean() represents the mean operation, angle() represents the phase operation, T _S represents the sampling interval, and θ represents the phase deviation.

When k=1, for the short preamble sequence k·N _s · T _S =1.6us, and when -π<angle(mean(d(i)))<π, the frequency offset can be effectively estimated, therefore, The short preamble sequence can estimate an effective frequency offset range of (-156.25*2, 156.25*2) KHz.

For the long preamble sequence k·N ₁ ·T _S =6.4us, and when -π<angle(mean(d(i)))<π, the frequency offset can be effectively estimated, and therefore, the short preamble sequence can be estimated. The effective frequency offset range is (-156.25/2, 156.25/2) KHz. Therefore, in the frame structure of 802.11p, the short preamble can be used for rough frequency offset estimation. The estimated range is (-156.25*2, 156.25*2) KHz, and the estimated absolute error is large; after the coarse frequency offset estimation The frequency offset estimation value is used to perform phase compensation on the subsequent data; finally, the long preamble code is used for fine frequency offset estimation, and the estimated range is (-156.25/2, 156.25/2) KHz.

In the existing methods of synchronous estimation and frequency offset estimation, when the noise is high, the coarse synchronization performance in the synchronous estimation is poor, which may easily lead to fine synchronization; and when the noise is high, the accuracy of the frequency offset estimation is also reduced.

Summary of the invention

The embodiment of the present disclosure provides a synchronization estimation method and a receiving end device, which are used to solve the problem that the existing synchronization estimation accuracy is low.

A synchronization estimation method provided by an embodiment of the present disclosure includes:

Receiving a data sequence including a preamble;

Performing timing estimation and/or frequency offset estimation according to a long preamble in the preamble;

The long preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is the same as the sequence in the long sequence and the first set length from the prefix, and the sequence in the suffix The sequence is the same as the sequence of the second set length in the long sequence and the suffix.

In an implementation, timing estimation is performed according to a long preamble in the preamble, including:

Calculating an autocorrelation value of the received sequence and its shifted sequence, determining a receiving moment of the receiving sequence whose autocorrelation value is greater than a set threshold as a first positioning position, and calculating a cross-correlation value of the base sequence corresponding to the long sequence corresponding to the long sequence Determining a receiving time of the receiving sequence corresponding to the peak as a second positioning position; wherein the receiving sequence is a data sequence received at different times, and an interval length between the shifting sequence and the receiving sequence is in a preamble Length of long sequence;

Calculating a position difference between the first positioning position and the second positioning position, and determining, according to the position difference, a cyclic shift sequence that generates the long sequence;

Determining, by the second positioning position, a difference of a receiving time of a receiving sequence corresponding to a cyclic shift sequence that generates the long sequence and a peak of an autocorrelation of the base sequence as a starting position of the long preamble .

Optionally, calculating a cross-correlation value of the base sequence corresponding to the long sequence of the received sequence, and determining a receiving moment of the received sequence corresponding to the peak as the second positioning location, including:

Calculating a cross-correlation value between the received sequence and the base sequence, and using the received time of the received sequence corresponding to the largest cross-correlation value as the receiving time of the received sequence corresponding to the peak; or

The cross-correlation value of the received sequence and the base sequence is calculated, and the reception time of the received sequence corresponding to the first cross-correlation value reaching the set threshold value is taken as the reception time of the received sequence corresponding to the peak.

Optionally, determining, according to the location difference, a cyclic shift sequence that generates the long sequence, including:

Obtaining a position of an autocorrelation peak of each cyclic shift sequence in the base sequence and the base sequence;

Calculating, respectively, a difference between the position difference and a position of an autocorrelation peak corresponding to each of the cyclic shift sequences;

The cyclic shift sequence corresponding to the obtained minimum difference is determined to generate a cyclic shift sequence of the long sequence.

Optionally, after determining to generate the cyclic shift sequence of the long sequence, the method further includes:

Determining, according to a preset correspondence between the sequence number shift sequence and the control information, control information corresponding to the cyclic shift sequence generating the long sequence;

The control information includes at least one of the following information: a cyclic prefix CP length, a scrambling code sequence number that scrambles the data, and pilot code information.

In an implementation, performing frequency offset estimation according to the long preamble in the preamble, including:

For each received sequence, calculating a product of the received sequence and the phase offset value obtained by the determined fractional multiple offset estimation, and using the obtained sequence as an intermediate sequence; the start position of the long preamble obtained by timing estimation As a starting point, a subsequence whose length is the sampling length corresponding to the long sequence is taken out from the intermediate sequence; according to the set sliding point, a length from the subsequence is taken as a long sequence in the preamble a sliding sequence corresponding to the effective bandwidth length, and calculating a cross-correlation value of each of the sliding sequence and the frequency domain sequence corresponding to the base sequence;

An integer multiple frequency offset value is determined according to the cross-correlation value corresponding to each received sequence.

Optionally, determining an integer multiple frequency offset value according to the cross-correlation value corresponding to each received sequence, including:

Determining, for each received sequence, whether a ratio of a maximum value of the cross-correlation values corresponding to the received sequence to an average of other cross-correlation values other than the maximum value reaches a set threshold;

The frequency offset value corresponding to the sliding point corresponding to the maximum cross-correlation value of the set threshold is determined as the integer multiple frequency offset value according to a preset relationship between the sliding point and the frequency offset value.

Based on any of the above embodiments, the long sequence is an m sequence, or a Zadoff-Chu sequence.

A receiving end device provided by an embodiment of the present disclosure includes:

a receiving module, configured to receive a data sequence including a preamble;

a processing module, configured to perform timing estimation and/or frequency offset estimation according to a long preamble in the preamble;

The long preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is the same as the sequence in the long sequence that is separated from the prefix by a first set length, and the sequence in the suffix The same sequence as the second set length from the suffix in the long sequence.

In an implementation, the processing module performs timing estimation according to the long preamble in the preamble, including:

Optionally, the processing module calculates a cross-correlation value of the base sequence corresponding to the long sequence of the received sequence, and determines a receiving moment of the received sequence corresponding to the peak as the second positioning location, including:

Optionally, the processing module determines, according to the location difference, a cyclic shift sequence that generates the long sequence, including:

Optionally, after the processing module determines to generate the cyclic shift sequence of the long sequence, the processing module is further configured to:

Based on any of the foregoing embodiments, the processing module performs frequency offset estimation according to the long preamble in the preamble, including:

For each received sequence, calculating a product of the received sequence and the phase offset value obtained by the determined fractional multiple offset estimation, and using the obtained sequence as an intermediate sequence; the start position of the long preamble obtained by timing estimation As a starting point, a subsequence whose length is a sampling length corresponding to a long sequence in the preamble is taken out from the intermediate sequence; according to the set sliding point, a length from the subsequence is respectively taken as the preamble a sliding sequence of effective bandwidth lengths corresponding to the long sequence in the medium, and calculating a cross-correlation value of each of the sliding sequence corresponding to the frequency domain sequence of the base sequence;

Optionally, the processing module determines an integer multiple frequency offset value according to the cross-correlation value corresponding to each received sequence, including:

The embodiment of the present disclosure further provides another receiving end device, including a processor and a transceiver, where

A processor for reading a program in the memory, performing the following process:

Receiving, by the transceiver, a data sequence including a preamble; and performing timing estimation and/or frequency offset estimation according to the long preamble in the preamble;

The long preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is the same as the sequence in the long sequence that is separated from the prefix by a first set length, and the sequence in the suffix The same sequence as the second set length of the long sequence from the suffix;

A transceiver for receiving and transmitting data under the control of a processor.

In an implementation, the processor performs timing estimation according to the long preamble in the preamble, including:

Optionally, the processor calculates a cross-correlation value of the base sequence corresponding to the long sequence of the received sequence, and determines a receiving moment of the received sequence corresponding to the peak as the second positioning location, including:

Optionally, the processor determines, according to the location difference, a cyclic shift sequence that generates the long sequence, including:

Calculating, respectively, a difference between the position difference and a position of an autocorrelation peak corresponding to each of the cyclic shift sequences; and

Optionally, after the processor determines to generate a cyclic shift sequence of the long sequence in the long preamble, the processor is further configured to:

The control information includes at least one of the following information: a CP length, a scrambling code sequence number that scrambles the data, and pilot code information.

Based on any of the foregoing embodiments, the processor performs frequency offset estimation according to the long preamble in the preamble, including:

Optionally, the processor determines, according to the cross-correlation value corresponding to each received sequence, an integer multiple offset value, including:

The embodiment of the present disclosure provides a new preamble structure, where the long preamble of the preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is separated from the sequence by a first set length in the long sequence. Similarly, the sequence in the suffix is the same as the sequence in the long sequence and the suffix from the second set length. Since the synchronization estimation is performed, the sequence carried in the pre- and post-suffixes of the long preamble and the segment in the long sequence may be utilized. The same structural characteristics of the sequence, thereby increasing the speed and accuracy of the synchronization estimation.

DRAWINGS

1 is a schematic diagram of a commonly used channel structure;

2 is a schematic diagram of a frame structure of 802.11p;

FIG. 3 is a schematic structural diagram of a frame according to an embodiment of the present disclosure;

FIG. 4 is a schematic flowchart diagram of a synchronization estimation method according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of a first receiving end device according to an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of a second receiving end device according to an embodiment of the present disclosure.

detailed description

In the embodiment of the present disclosure, based on the new preamble structure, the synchronization estimation is performed. The long preamble in the preamble includes a prefix, a long sequence, and a suffix, where the sequence in the prefix is separated from the long sequence by the prefix. A sequence of a set length is the same, and the sequence in the suffix is the same as the sequence in the long sequence and the suffix is a second set length, because the length of the preamble provided by the embodiment of the present disclosure is long. The preamble includes the same two sequences before and after, and the synchronization estimation speed and accuracy can be improved when performing synchronization estimation.

The new preamble structure provided by the embodiment of the present disclosure will be described in detail below.

The preamble provided by the embodiment of the present disclosure includes a short preamble (abbreviated as short code) and a long preamble (abbreviated as long code), and the structures of the short preamble and the long preamble are respectively described in detail below.

1. Short preamble;

The short preamble provided by the embodiment of the present disclosure carries at least two identical short sequences, and the specific number of short sequences is determined by the total length of the short preamble and the length of each short sequence.

The short preamble provided by the embodiment of the present disclosure may have a length of 16, 32, and 64 sampling points (one of which is a digital signal value), and is mainly used for implementing fast AGC estimation and adjustment, or for coarse timing. And frequency offset estimation.

Optionally, when selecting a short sequence for the short preamble, the autocorrelation is better (that is, the autocorrelation value obtained by performing the autocorrelation operation is greater than the set first threshold), and the cross correlation is poor ( That is, a sequence in which the cross-correlation value obtained by the cross-correlation operation is smaller than the set second threshold value is taken as a short sequence. Alternatively, the short sequence employs an m-sequence, or a ZC (Zaddoff-Chu) sequence.

Second, the long preamble;

The long preamble provided by the embodiment of the present disclosure includes a prefix, a long sequence and a suffix in sequence, wherein the sequence in the prefix is the same as the sequence in the long sequence and the first set length from the prefix, and the sequence in the suffix is neutralized with the long sequence. The suffix is the same sequence from the second set length.

Among them, the sequence with the same prefix in the long sequence and the sequence with the same suffix in the long sequence do not overlap each other.

Specifically, it is assumed that the long sequence includes A, B, and C in sequence, the sequence in the prefix is the same as the sequence in C, the sequence in the suffix is the same as the sequence in A, and the sequence in the prefix is the first from the sequence in C. The set length means that the Mth sample point of the sequence in the prefix is separated from the Mth sample point of the sequence in C by a first set length, and M is a positive integer.

In the implementation, the first set length and the second set length may be the same or different. Optional In order to reduce the complexity of the synchronization estimation and increase the speed of the synchronization estimation, the first set length is the same as the second set length.

Optionally, in order to further reduce the complexity of the synchronization estimation and increase the speed of the synchronization estimation, the first set length is 2 ⁿ sample points (ie, n) is a positive integer; the second set length is 2 ⁿ , n is A positive integer. For example, the first set length is 512 points (ie, 512 sample points), and the second set length is also 512 points; for example, the first set length is 256 points, and the second set length is 512 points.

The long preamble provided by the embodiment of the present disclosure mainly performs functions such as timing, frequency offset estimation, and control information identification.

Optionally, when selecting a long sequence for the long preamble, the autocorrelation is better (ie, the autocorrelation value obtained by performing the autocorrelation operation is greater than the set first threshold), and the cross correlation is poor ( That is, a sequence in which the cross-correlation value obtained by the cross-correlation operation is smaller than the set second threshold) is used as a long sequence. Alternatively, the long sequence is an m sequence, or a ZC sequence.

The long sequence of embodiments of the present disclosure may be generated by any of the time domain cyclic shift sequences in the set base sequence. For the ZC sequence, the base sequence set corresponding to the ZC sequence, and the time domain cyclic shift sequence corresponding to each base sequence, refer to section 5.7.2 of the 3GPP 36.211 protocol. For an m-sequence, any of the sets of all m-sequences can be understood as a base sequence, and sequences other than any of the sequences can be understood as a time-domain cyclic shift sequence of any of the sequences.

The composition of the long preamble is illustrated by a 512-point ZC sequence (ie, the ZC sequence includes 512 sample points) and a 10 MHz bandwidth as an example:

The long preamble includes a 512-point time domain Zadoff-chu sequence and pre- and post-suffixes, wherein the lengths of the pre- and post-suffixes are determined by the total length of the 512-point ZC sequence; wherein the 512-point time-domain ZC sequence is complemented by the 301-point frequency-domain ZC sequence. After zero, the 512-point IFFT transform is performed; and the 301-point frequency-domain ZC sequence is generated by a cyclic shift sequence of a base sequence, and different base sequences correspond to different cyclic shift sequences, for example, if the base sequence If the serial number is 1, the sequence number of the cyclic shift sequence can be selected as one of [0, 21, 23]. For the content of the ZC sequence, such as the base sequence, the cyclic shift sequence of the base sequence, how to generate the ZC sequence, etc., refer to Section 5.7.2 of the 3GPP 36.211 protocol.

A preferred structural diagram of the frame structure of the embodiment of the present disclosure is shown in FIG. 3. In FIG. 3, M represents a short code in the preamble, and the long code in the figure adopts a ZC sequence, and the ZC sequence includes A, B, and C. The three parts, wherein the sequence in the prefix of the long code is the same as C, the sequence in the suffix of the long code is the same as A, the prefix is 512 samples from C, and the suffix is 512 samples away from A.

The embodiments of the present disclosure are further described in detail below with reference to the accompanying drawings. It is to be understood that the embodiments described herein are for the purpose of illustration and illustration

As shown in FIG. 4, an embodiment of the present disclosure provides a synchronization estimation method, where the method includes:

Step 41: Receive a data sequence that includes a preamble sent by the sending end.

Step 42: Perform timing estimation and/or frequency offset estimation according to the long preamble in the preamble to implement synchronization with the transmitting end.

The long preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is the same as the sequence in the long sequence and the first set length from the prefix, and the sequence in the suffix is separated from the long sequence by the suffix. The sequence of the second set length is the same.

In the embodiment of the present disclosure, the execution body of the foregoing step 41 and step 42 is a receiving end device, such as a terminal.

In the embodiment of the present disclosure, a new preamble structure is provided, where the long preamble of the preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is separated from the prefix by the first set length in the long sequence. The sequence in the suffix is the same as the sequence in the long sequence and the suffix is separated from the second set length. Since the synchronization estimation is performed, the sequence carried in the pre- and post-suffixes in the long preamble and the long sequence can be utilized. The same structural characteristics of a certain sequence, thereby improving the speed and accuracy of the synchronization estimation.

In step 42, the timing estimation is performed according to the long preamble in the preamble, including the following steps:

Calculating an autocorrelation value of the received sequence and its shift sequence, and determining a receiving moment of the received sequence whose autocorrelation value is greater than a set threshold as the first positioning position

And calculating a cross-correlation value of the base sequence corresponding to the long sequence in the received sequence and the long preamble, and determining the reception time of the received sequence corresponding to the peak as the second positioning position

The receiving sequence is a data sequence received at different times, and the length of the interval between the shift sequence and the received sequence is the length of the long sequence in the preamble;

Calculating the position difference between the first positioning position and the second positioning position

Determining, according to the position difference, a cyclic shift sequence that generates a long sequence;

a difference between the second positioning position and the reception time of the reception sequence corresponding to the peak of the auto-correlation of the base sequence generated by the cyclic shift sequence of the long sequence

Determined as the starting position of the long preamble (ie, the time domain location of the first sample point in the long preamble).

Specifically, the mobile autocorrelation operation is performed on the received sequence, and the shift length is the length of the long sequence, so that the approximate timing of the long preamble can be obtained by using the same prefix in the long preamble in the frame structure and the third sequence in the long sequence. position

(ie, the approximate starting position of the long preamble); then use the local base sequence and the received sequence to perform cross-correlation operations to determine

Last according to

Determining an accurate timing position of the long preamble (ie, an accurate starting position of the long preamble) to determine the exact timing of the received sequence corresponding to the peak of the auto-correlation of the cyclic sequence of the long sequence and the base sequence. Synchronize.

In the foregoing timing estimation process, the cross-correlation value of the received sequence and the base sequence is calculated, and the receiving time of the receiving sequence corresponding to the peak is determined as the second positioning position, including:

The cross-correlation value of the received sequence and the base sequence is calculated, and the reception time of the received sequence corresponding to the first cross-correlation value reaching the set threshold value is taken as the reception time of the reception sequence corresponding to the peak.

In the above timing estimation process, according to the position difference, determining a cyclic shift sequence for generating a long sequence includes:

Obtaining the position of the autocorrelation peak of each cyclic shift sequence and the base sequence in the base sequence;

Calculating a difference between a position difference and a position of an autocorrelation peak corresponding to each cyclic shift sequence, respectively;

The cyclic shift sequence corresponding to the obtained minimum difference is determined as a cyclic shift sequence that generates a long sequence.

Specifically, the position of the autocorrelation peak of the cyclic shift sequence corresponding to each base sequence is known, and as long as the sequence number of the base sequence is known, the cyclic shift sequence of the base sequence and each cyclic shift sequence can be known. The position of the autocorrelation peak with the base sequence. Assuming that the base sequence corresponds to three cyclic shift sequences, the positions of the autocorrelation peaks of the three cyclic shift sequences and the base sequence are Δθ ₁ , Δθ ₂ , Δθ ₃ , respectively, and the method for determining the cyclic shift sequence for generating the long sequence is

Therefore, it is judged that the cyclic shift sequence of the birth growth sequence is a cyclic shift sequence for the serial number.

Further, according to the determined cyclic shift sequence for generating a long sequence, the position of the autocorrelation peak of the cyclic shift sequence and the base sequence is Δθ _j , and finally

And Δθ _j , to determine the exact timing position, ie

It should be noted that, when performing timing estimation, in the embodiment of the present disclosure, in addition to the foregoing priority manner, the existing rough estimation (using the short preamble in the preamble for rough estimation) and fine estimation may be used ( Timing estimation is performed by a method of performing coarse estimation using a long preamble in the preamble.

Optionally, after determining to generate a cyclic shift sequence of the long sequence, the method further includes:

Specifically, different cyclic shift sequences may be used to indicate different control information, so that the receiving end can obtain the control information corresponding to the cyclic shift sequence after determining the cyclic shift sequence for generating the long sequence. The different cyclic shift sequences specifically indicate which control information can be determined by the receiving end and the transmitting end, or can be specified in the protocol, as long as the receiving end and the transmitting end have the same understanding of the control information indicated by the different cyclic shift sequences. Just fine.

In the implementation, the frequency offset estimation is performed according to the long preamble in the preamble, including:

For each received sequence, the product of the received sequence and the phase offset value obtained by the determined fractional octave offset estimation is calculated, and the obtained sequence is used as an intermediate sequence; the long preamble obtained by timing estimation is obtained. The starting position is the starting point, and a subsequence whose length is the sampling length corresponding to the long sequence in the preamble is taken from the intermediate sequence; according to the set sliding point, the long sequence in the preamble is taken from the subsequence respectively a sliding sequence corresponding to the effective bandwidth length, and respectively calculating a cross-correlation value of the frequency domain sequence corresponding to each sliding sequence and the base sequence;

The sampling length represents the number of sampling points in the time domain, and the sampling length is greater than or equal to the length of the long sequence; the effective bandwidth length is the physical quantity in the frequency domain.

It should be noted that the frequency offset estimation includes a fractional multiple frequency offset estimation (ie, a fractional multiple carrier spacing offset) and an integer multiple frequency offset estimation (integer multiple carrier spacing offset), wherein the fractional multiple frequency offset is adopted. According to the prior art, if the sampling rate of the system is 15.36 MHz, the fractional octave bias estimation range is 15.36·10 ⁶ ·(-π,π)/(2π·512)=(-15 kHz, 15 kHz), the specific process I won't go into details here. The frequency offset exceeding the fractional frequency offset estimation range is completed by the integer multiple frequency offset estimation. The embodiment of the present disclosure provides a processing procedure of the preferred integer multiple frequency offset estimation, which is specifically as follows:

First, remove the influence of the fractional octave offset, that is, multiply the received sequence r(n) by the phase offset caused by the fractional octave offset to obtain r _t (n)=r(n)·exp(j·2π· nT _s · ε ₀ ), where T _s is the sampling interval, ε ₀ is the fractional multiple offset, n is the sampling point index, and r _t (n) is the sequence after the fractional multiple offset correction;

Then, starting from the starting position of the preamble obtained by the timing estimation, a subsequence r _f (n) whose length is the sampling length corresponding to the long sequence in the preamble is taken from r _t (n); for example, if long The sequence adopts the ZC sequence, and the sub-sequence r _f (n) having a length of 512 points is taken out from r _t (n), and the sub-sequence obtained here is a frequency domain sequence;

Then, according to the set sliding point, a sliding sequence whose length is the effective bandwidth length corresponding to the long sequence in the preamble is respectively taken from r _f (n), and each sliding sequence and the base sequence L _f (k) are respectively calculated. Corresponding cross-correlation value of the frequency domain sequence; for example, if the long sequence adopts the ZC sequence, a sliding sequence having a length of 301 points is taken from r _f (n);

Finally, an integer octave bias value is determined according to the cross-correlation value corresponding to each received sequence.

It should be noted that the sliding range of the sliding sequence is related to the predetermined crystal oscillator offset range, and the ZC sequence is taken as an example for the long sequence. If the frequency offset jitter of 5 ppm is considered, two points are swept left and right, and a total of five points are determined. The sliding sequence can be, specifically: 512 points r _f (n) intermediate position acquires 301 points as the first sliding sequence, and the first sliding sequence slides 1 point to the left to obtain 301 points as the second sliding sequence, the first The sliding sequence slides 2 points to the left to obtain 301 points as the third sliding sequence. The first sliding sequence slides 1 point to the right to obtain 301 points as the fourth sliding sequence, and the first sliding sequence slides 2 points to the right to obtain 301. The point serves as the fifth sliding sequence. If the jitter of the 20 ppm frequency offset is considered, then 8 points are swept left and right, and a total of 17 points of the sliding sequence can be determined.

In the foregoing frequency offset estimation process, determining an integer multiple frequency offset value according to the cross-correlation value corresponding to each received sequence, including:

The frequency offset value corresponding to the sliding point corresponding to the maximum cross-correlation value of the set threshold is determined as an integer multiple frequency offset value according to a preset relationship between the sliding point and the frequency offset value.

It should be noted that the correspondence between the sliding point and the frequency offset value is preset. Here, it is considered that the other sliding points other than the sliding point corresponding to the maximum cross-correlation value are noise, and the frequency offset value corresponding to the sliding point corresponding to the maximum cross-correlation value of the set threshold M is determined as an integer multiple frequency offset value.

The above method processing flow can be implemented by a software program, which can be stored in a storage medium, and when the stored software program is called, the above method steps are performed.

Based on the same inventive concept, a receiving end device is further provided in the embodiment of the present disclosure. Since the principle of solving the problem is similar to the foregoing synchronous estimating method, the implementation of the device may refer to the implementation of the method, and the repeated description is not repeated. .

As shown in FIG. 5, a receiving end device provided by an embodiment of the present disclosure includes:

The receiving module 51 is configured to receive a data sequence that includes a preamble sent by the sending end.

The processing module 52 is configured to perform timing estimation and/or frequency offset estimation according to the long preamble in the preamble;

The long preamble includes a prefix, a long sequence, and a suffix, in which the prefix is included. The sequence is the same as the sequence of the long sequence that is separated from the prefix by a first set length, and the sequence in the suffix is the same as the sequence of the long sequence that is separated from the suffix by a second set length.

The receiving end device provided by the embodiment of the present disclosure performs synchronization estimation based on a new preamble structure, and the long preamble of the preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is separated from the long sequence by the prefix. The sequence of a set length is the same, and the sequence in the suffix is the same as the sequence of the second set length in the long sequence and the suffix. Since the synchronization estimation is performed, the sequence carried in the front and the suffix in the long preamble can be utilized. The same structural characteristics of a certain sequence in a long sequence, thereby improving the speed and accuracy of the synchronization estimation.

In an implementation, the processing module 52 performs timing estimation according to the long preamble in the preamble, including:

Optionally, the processing module 52 calculates a cross-correlation value of the base sequence corresponding to the long sequence of the received sequence, and determines a receiving moment of the received sequence corresponding to the peak as the second positioning location, including:

Optionally, the processing module 52 determines, according to the position difference, a cyclic shift that generates the long sequence. Sequence, including:

Optionally, after the processing module 52 determines to generate the cyclic shift sequence of the long sequence, the processing module 52 is further configured to:

Based on any of the foregoing embodiments, the processing module 52 performs frequency offset estimation according to the long preamble in the preamble, including:

Optionally, the processing module 52 determines an integer multiple frequency offset value according to the cross-correlation value corresponding to each received sequence, including:

Based on the same inventive concept, an embodiment of the present disclosure further provides another receiving end device, as shown in FIG. 6, including:

The processor 600 is configured to read a program in the memory 620 and perform the following process:

Receiving, by the transceiver 610, a data sequence including a preamble transmitted by the transmitting end; and performing timing estimation and/or frequency offset estimation according to the long preamble in the preamble;

The transceiver 610 is configured to receive and transmit data under the control of the processor 600.

Wherein, in FIG. 6, the bus architecture can include any number of interconnected buses and bridges, specifically linked by one or more processors represented by processor 600 and various circuits of memory represented by memory 620. The bus architecture can also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be further described herein. The bus interface provides an interface. Transceiver 610 can be a plurality of components, including a transmitter and a transceiver, providing means for communicating with various other devices on a transmission medium. The processor 600 is responsible for managing the bus architecture and general processing, and the memory 620 can store data used by the processor 600 in performing operations.

In an implementation, the processor 600 performs timing estimation according to the long preamble in the preamble, including:

Calculating a position difference between the first positioning position and the second positioning position, according to the position difference, Determining a cyclic shift sequence that generates the long sequence;

Optionally, the processor 600 calculates a cross-correlation value of the base sequence corresponding to the long sequence of the received sequence, and determines a receiving moment of the received sequence corresponding to the peak as the second positioning location, including:

Optionally, the processor 600 determines, according to the location difference, a cyclic shift sequence that generates the long sequence, including:

Optionally, after the processor 600 determines to generate a cyclic shift sequence of a long sequence in the long preamble, the processor 600 is further configured to:

Based on any of the foregoing embodiments, the processor 600 performs frequency offset estimation according to the long preamble in the preamble, including:

For each received sequence, calculate the phase of the received sequence and the determined fractional octave bias estimate a product of a bit offset value, the obtained sequence is taken as an intermediate sequence; starting position of the long preamble obtained by timing estimation is taken as a starting point, and a length from the intermediate sequence is taken as a long sequence in the preamble a subsequence of the corresponding sampling length; according to the set sliding point, a sliding sequence having a length corresponding to the effective bandwidth length of the long sequence in the preamble is respectively taken from the subsequence, and each sliding is calculated separately a cross-correlation value of a frequency domain sequence corresponding to the sequence and the base sequence;

Optionally, the processor 600 determines an integer multiple frequency offset value according to the cross-correlation value corresponding to each received sequence, including:

Those skilled in the art will appreciate that embodiments of the present disclosure can be provided as a method, system, or computer program product. Accordingly, the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment, or a combination of software and hardware aspects. Moreover, the present disclosure may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) including computer usable program code.

The present disclosure is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

While the preferred embodiment of the present disclosure has been described, it will be apparent that those skilled in the art can make further changes and modifications to the embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and the modifications

It will be apparent to those skilled in the art that various changes and modifications can be made in the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present invention cover the modifications and the modifications

Claims

A method for synchronous estimation, the method comprising:

Receiving a data sequence including a preamble;

Performing timing estimation and/or frequency offset estimation according to a long preamble in the preamble;

The long preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is the same as the sequence in the long sequence and the first set length from the prefix, and the sequence in the suffix The sequence is the same as the sequence of the second set length in the long sequence and the suffix.
The method of claim 1 wherein timing estimation is performed based on a long preamble in the preamble, comprising:

Calculating an autocorrelation value of the received sequence and its shifted sequence, determining a receiving moment of the receiving sequence whose autocorrelation value is greater than a set threshold as a first positioning position, and calculating a cross-correlation value of the base sequence corresponding to the long sequence corresponding to the long sequence Determining a receiving time of the receiving sequence corresponding to the peak as a second positioning position; wherein the receiving sequence is a data sequence received at different times, and an interval length between the shifting sequence and the receiving sequence is in a preamble Length of long sequence;

Calculating a position difference between the first positioning position and the second positioning position, and determining, according to the position difference, a cyclic shift sequence that generates the long sequence;

Determining, by the second positioning position, a difference of a receiving time of a receiving sequence corresponding to a cyclic shift sequence that generates the long sequence and a peak of an autocorrelation of the base sequence as a starting position of the long preamble .
The method of claim 2, wherein calculating a cross-correlation value of the base sequence corresponding to the long sequence of the received sequence, and determining the receiving time of the received sequence corresponding to the peak as the second positioning position comprises:

Calculating a cross-correlation value between the received sequence and the base sequence, and using the received time of the received sequence corresponding to the largest cross-correlation value as the receiving time of the received sequence corresponding to the peak; or

The cross-correlation value of the received sequence and the base sequence is calculated, and the reception time of the received sequence corresponding to the first cross-correlation value reaching the set threshold value is taken as the reception time of the received sequence corresponding to the peak.
The method of claim 2, wherein determining the cyclic shift sequence for generating the long sequence based on the position difference comprises:

Obtaining a position of an autocorrelation peak of each cyclic shift sequence in the base sequence and the base sequence;

Calculating, respectively, a difference between the position difference and a position of an autocorrelation peak corresponding to each of the cyclic shift sequences;

The cyclic shift sequence corresponding to the obtained minimum difference is determined to generate a cyclic shift sequence of the long sequence.
The method of claim 2, wherein after determining to generate the cyclic shift sequence of the long sequence, the method further comprises:

Determining, according to a preset correspondence between the sequence number shift sequence and the control information, control information corresponding to the cyclic shift sequence generating the long sequence;

The control information includes at least one of the following information: a cyclic prefix CP length, a scrambling code sequence number that scrambles the data, and pilot code information.
The method according to any one of claims 1 to 5, wherein the frequency offset estimation is performed according to the long preamble in the preamble, including:

For each received sequence, calculating a product of the received sequence and the phase offset value obtained by the determined fractional multiple offset estimation, and using the obtained sequence as an intermediate sequence; the start position of the long preamble obtained by timing estimation As a starting point, a subsequence whose length is the sampling length corresponding to the long sequence is taken out from the intermediate sequence; according to the set sliding point, a length from the subsequence is taken as a long sequence in the preamble a sliding sequence corresponding to the effective bandwidth length, and calculating a cross-correlation value of each of the sliding sequence and the frequency domain sequence corresponding to the base sequence;

An integer multiple frequency offset value is determined according to the cross-correlation value corresponding to each received sequence.
The method of claim 6, wherein determining an integer octave offset value according to a cross-correlation value corresponding to each received sequence comprises:

Determining, for each received sequence, whether a ratio of a maximum value of the cross-correlation values corresponding to the received sequence to an average of other cross-correlation values other than the maximum value reaches a set threshold;

The frequency offset value corresponding to the sliding point corresponding to the maximum cross-correlation value of the set threshold is determined as the integer multiple frequency offset value according to a preset relationship between the sliding point and the frequency offset value.
The method according to any one of claims 1 to 5, wherein the long sequence is an m sequence, or a Zadoff-Chu sequence.
A receiving end device, the device comprising:

a receiving module, configured to receive a data sequence including a preamble;

a processing module, configured to perform timing estimation and/or frequency offset estimation according to a long preamble in the preamble;

The long preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is the same as the sequence in the long sequence that is separated from the prefix by a first set length, and the sequence in the suffix The same sequence as the second set length from the suffix in the long sequence.
The device of claim 9, wherein the processing module performs timing estimation according to the long preamble in the preamble, including:

Calculating an autocorrelation value of the received sequence and its shifted sequence, determining a receiving moment of the receiving sequence whose autocorrelation value is greater than a set threshold as a first positioning position, and calculating a cross-correlation value of the base sequence corresponding to the long sequence corresponding to the long sequence Determining a receiving time of the receiving sequence corresponding to the peak as a second positioning position; wherein the receiving sequence is a data sequence received at different times, and an interval length between the shifting sequence and the receiving sequence is in a preamble Length of long sequence;

Calculating a position difference between the first positioning position and the second positioning position, and determining, according to the position difference, a cyclic shift sequence that generates the long sequence;

Determining, by the second positioning position, a difference of a receiving time of a receiving sequence corresponding to a cyclic shift sequence that generates the long sequence and a peak of an autocorrelation of the base sequence as a starting position of the long preamble .
The apparatus of claim 10 wherein said processing module calculates a received sequence and Determining the cross-correlation value of the base sequence corresponding to the long sequence, and determining the receiving time of the receiving sequence corresponding to the peak as the second positioning position, including:

Calculating a cross-correlation value between the received sequence and the base sequence, and using the received time of the received sequence corresponding to the largest cross-correlation value as the receiving time of the received sequence corresponding to the peak; or

The cross-correlation value of the received sequence and the base sequence is calculated, and the reception time of the received sequence corresponding to the first cross-correlation value reaching the set threshold value is taken as the reception time of the received sequence corresponding to the peak.
The apparatus of claim 10, wherein the processing module determines to generate a cyclic shift sequence of the long sequence according to the position difference, comprising:

Obtaining a position of an autocorrelation peak of each cyclic shift sequence in the base sequence and the base sequence;

Calculating, respectively, a difference between the position difference and a position of an autocorrelation peak corresponding to each of the cyclic shift sequences;

The cyclic shift sequence corresponding to the obtained minimum difference is determined to generate a cyclic shift sequence of the long sequence.
The apparatus of claim 10, wherein the processing module determines to generate the cyclic shift sequence of the long sequence, further for:

Determining, according to a preset correspondence between the sequence number shift sequence and the control information, control information corresponding to the cyclic shift sequence generating the long sequence;

The control information includes at least one of the following information: a cyclic prefix CP length, a scrambling code sequence number that scrambles the data, and pilot code information.
The device according to any one of claims 9 to 13, wherein the processing module performs frequency offset estimation according to a long preamble in the preamble, including:

For each received sequence, calculating a product of the received sequence and the phase offset value obtained by the determined fractional multiple offset estimation, and using the obtained sequence as an intermediate sequence; the start position of the long preamble obtained by timing estimation As a starting point, a subsequence whose length is a sampling length corresponding to a long sequence in the preamble is taken out from the intermediate sequence; according to the set sliding point, a length from the subsequence is respectively taken as the preamble The sliding sequence of the effective bandwidth length corresponding to the long sequence in the middle, and is calculated separately a cross-correlation value of a frequency domain sequence corresponding to each of the sliding sequences and the base sequence;

An integer multiple frequency offset value is determined according to the cross-correlation value corresponding to each received sequence.
The device according to claim 14, wherein the processing module determines an integer multiple frequency offset value according to a cross-correlation value corresponding to each received sequence, including:

Determining, for each received sequence, whether a ratio of a maximum value of the cross-correlation values corresponding to the received sequence to an average of other cross-correlation values other than the maximum value reaches a set threshold;

The frequency offset value corresponding to the sliding point corresponding to the maximum cross-correlation value of the set threshold is determined as the integer multiple frequency offset value according to a preset relationship between the sliding point and the frequency offset value.
The apparatus according to any one of claims 9 to 13, wherein the long sequence is an m sequence, or a Zadoff-Chu sequence.
A receiving end device, comprising a processor and a transceiver, wherein

A processor for reading a program in the memory, performing the following process:

Receiving, by the transceiver, a data sequence including a preamble; and performing timing estimation and/or frequency offset estimation according to the long preamble in the preamble;

The long preamble includes a prefix, a long sequence, and a suffix, wherein the sequence in the prefix is the same as the sequence in the long sequence that is separated from the prefix by a first set length, and the sequence in the suffix The same sequence as the second set length of the long sequence from the suffix;

A transceiver for receiving and transmitting data under the control of a processor.