CN108512789B - Synchronization detection method, synchronization detection device, communication-capable device and storage medium - Google Patents

Synchronization detection method, synchronization detection device, communication-capable device and storage medium Download PDF

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CN108512789B
CN108512789B CN201810220269.9A CN201810220269A CN108512789B CN 108512789 B CN108512789 B CN 108512789B CN 201810220269 A CN201810220269 A CN 201810220269A CN 108512789 B CN108512789 B CN 108512789B
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timing
frequency offset
candidate
value
timing metric
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CN108512789A (en
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徐子龙
刘为
童进
宋怡昕
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Seventh Research Institute Of China Electronics Technology Group Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/0035—Synchronisation arrangements detecting errors in frequency or phase
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
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    • H04L2027/0026—Correction of carrier offset

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Abstract

The application relates to a synchronous detection method, a synchronous detection device, equipment with communication capability and a storage medium, wherein the synchronous detection method comprises the following steps: acquiring a maximum preset number of timing metric values in a preset observation range; determining a preset number of candidate timing positions according to the timing positions corresponding to the preset number of timing metric values; determining a preset number of candidate receiving sequences according to the preset number of candidate timing positions; obtaining a frequency offset estimation value according to the candidate receiving sequence, and performing frequency offset compensation on the candidate receiving sequence to obtain a candidate receiving sequence after frequency offset compensation; determining the correlation result of the candidate receiving sequence after each frequency offset compensation and the local reference sequence; and determining the timing metric value and the frequency deviation estimation value corresponding to the correlation result with the maximum value as a final timing estimation position and a final frequency deviation estimation value. The problem that timing errors are easy to occur due to the fact that timing detection is affected by frequency deviation, the larger the frequency deviation is, the more obvious the influence is solved.

Description

Synchronization detection method, synchronization detection device, communication-capable device and storage medium
Technical Field
The present application relates to the field of communications technologies, and in particular, to a synchronization detection method and apparatus, a device with communication capability, and a storage medium.
Background
Inter-device communication requires the establishment of time and frequency synchronization. Time synchronization is used for determining a correct symbol starting position in a time domain; carrier frequency synchronization is used to reduce or eliminate the effect of frequency error due to crystal offset and doppler effect. Timing synchronization is typically performed first and then frequency synchronization is performed because the frequency offset estimation often depends on the candidate received sequence, which needs to be derived on the basis of timing synchronization. This means that the timing synchronization needs to be performed in the situation that the frequency offset has not been corrected, and therefore it is very important to examine the performance of the timing synchronization in the environment of the frequency offset.
The timing estimate position may be determined by searching for the position corresponding to the maximum timing metric value over a range of time, typically the period of the reference sequence. One common type of timing metric can be summarized as follows:
Figure BDA0001599497290000011
where N represents the nth received sample, N is the length of the reference sequence, P is a positive integer that divides N exactly, "| -" represents an absolute value operation, "-" represents a conjugate operation, and a timing metric MP(n) the calculation process can be divided into three steps: first, a received signal sequence { r (N + l), l ═ 0, 1, …, N-1} and a local reference sequence { x (l) }, l ═ 0, 1, …, N-1} are equally divided into P segments in the same manner, then the squares of the cross-correlation modulus values of each segment of the received sequence and the corresponding local sequence are squared, and then the squares of the P modulus values are accumulated.
The timing metric MP(n) is susceptible to frequency deviation (especially, P is small), which results in timing detection errors, and the larger the frequency deviation is, the more obvious the influence is, and the more easily timing errors occur.
Disclosure of Invention
In view of the above, it is necessary to provide a synchronization detection method, a synchronization detection apparatus, a device with communication capability, and a storage medium, for solving the problem that timing errors are more likely to occur as the frequency offset is larger and the influence of timing detection is more obvious.
A synchronization detection method, comprising:
acquiring a maximum preset number of timing metric values in a preset observation range;
determining a preset number of candidate timing positions according to the receiving sampling point positions corresponding to the preset number of timing metric values;
determining a preset number of candidate receiving sequences according to the preset number of candidate timing positions;
determining a corresponding correlation result after frequency offset compensation of each candidate receiving sequence;
and determining the timing metric value and the frequency deviation estimation value corresponding to the correlation result with the maximum value as a final timing estimation position and a final frequency deviation estimation value.
In one embodiment, the step of determining the correlation result corresponding to each candidate received sequence after frequency offset compensation includes:
respectively carrying out frequency offset estimation on each candidate receiving sequence to obtain corresponding frequency offset estimation values;
respectively carrying out frequency offset compensation on the corresponding candidate receiving sequences by adopting the obtained frequency offset estimation values to obtain candidate receiving sequences after each frequency offset compensation;
and respectively correlating the candidate receiving sequences after each frequency offset compensation with the local reference sequence to obtain each correlation result.
In one embodiment, the correlation result comprises a cross-correlation modulus or a square of the cross-correlation modulus.
In one embodiment, the step of obtaining a maximum preset number of timing metric values within a preset observation range includes:
acquiring a timing metric value in a preset observation range;
selecting a preset number of timing metric values from the obtained timing metric values in a preset observation range, and respectively storing the timing metric values in the preset number of buffers;
selecting a currently undetermined timing metric value from a preset observation range;
when the minimum value in the timing metric values stored in the buffers is smaller than the currently pending timing metric value, replacing the value in the buffer corresponding to the minimum value with the currently pending timing metric value; and after the replacement or when the minimum value is larger than the currently undetermined timing metric value, returning to the step of selecting the currently undetermined timing metric value from the preset observation range until all timing metric values in the preset observation range are selected as the currently undetermined timing metric value;
and determining each timing metric value stored in each buffer as the maximum preset number of timing metric values.
In one of the embodimentsSaid candidate received sequence is passed
Figure BDA0001599497290000031
Performing frequency offset estimation, the
Figure BDA0001599497290000032
Figure BDA0001599497290000033
For the frequency offset estimation value, N is the length of the candidate receiving sequence, arg { } represents the operation of taking the phase angle, N is the nth receiving sampling point, Δ f is the subcarrier interval, y is the symbol length of the candidate receiving sequence, and the symbol length is the symbol length of the candidate receiving sequencei(n) is a candidate received sequence,
Figure BDA0001599497290000034
for the conjugate of the local reference sequence, "+" indicates the conjugate operation.
In one embodiment, the candidate received sequence is obtained by
Figure BDA0001599497290000035
The frequency offset compensation is carried out and,
Figure BDA0001599497290000036
for the frequency offset estimation, Ts＝1/fsIs the sampling interval.
Figure BDA0001599497290000037
For candidate received sequences after frequency offset compensation, yiAnd (n) is a candidate receiving sequence.
In one embodiment, a synchronization detection apparatus includes:
the timing metric value acquisition module is used for acquiring the maximum preset number of timing metric values in a preset observation range;
a candidate timing position determining module, configured to determine a preset number of candidate timing positions according to the receiving sampling point positions corresponding to the preset number of timing metric values;
a candidate receiving sequence determining module, configured to determine a preset number of candidate receiving sequences according to the preset number of candidate timing positions;
the frequency offset compensation and correlation result determining module is used for determining the corresponding correlation result after the frequency offset compensation is carried out on each candidate receiving sequence;
and the final timing estimation position and final frequency deviation estimation value determining module is used for determining the timing metric value and the frequency deviation estimation value corresponding to the correlation result with the maximum value as the final timing estimation position and the final frequency deviation estimation value.
In one embodiment, the frequency offset compensation and correlation result determination module comprises:
the frequency offset estimation value unit is used for respectively carrying out frequency offset estimation on each candidate receiving sequence to obtain corresponding frequency offset estimation values;
the frequency offset compensation unit is used for respectively carrying out frequency offset compensation on the corresponding candidate receiving sequences by adopting the obtained frequency offset estimation values to obtain the candidate receiving sequences after each frequency offset compensation;
and the correlation result determining unit is used for correlating the candidate receiving sequences after each frequency offset compensation with the local reference sequence respectively to obtain each correlation result.
In one embodiment, an apparatus with communication capability includes a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the synchronization detection method when executing the time synchronization.
In one embodiment, a storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the synchronization detection method.
The synchronous detection method, the synchronous detection device, the equipment with the communication capability and the storage medium acquire the maximum preset number of timing metric values in the preset observation range; determining a preset number of candidate timing positions according to the receiving sampling point positions corresponding to the preset number of timing metric values; determining a preset number of candidate receiving sequences according to the preset number of candidate timing positions; determining a correlation result corresponding to each candidate receiving sequence; and determining the timing metric value and the frequency deviation estimation value corresponding to the correlation result with the maximum value as a final timing estimation position and a final frequency deviation estimation value. The correct timing position is selected through the steps according to the position corresponding to the maximum preset number of timing metric values in the preset observation range, and the problems that the timing detection is influenced by frequency deviation, the larger the frequency deviation is, the more obvious the influence is, and the timing error is easy to occur are solved.
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FIG. 1 is a flow chart of a synchronization detection method according to an embodiment of the present application;
FIG. 2 is a flow chart of a synchronization detection method according to another embodiment of the present application;
FIG. 3 is a flow chart of a synchronization detection method according to another embodiment of the present application;
fig. 4 is a block diagram of a synchronization detecting apparatus according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 1, a synchronization detection method performs the following steps S210 to S260:
step S210, obtaining a maximum preset number of timing metric values within a preset observation range.
Wherein the timing metric value is determined by a timing metric function
Figure BDA0001599497290000051
Figure BDA0001599497290000052
Where N denotes the nth received sample, N is the length of the reference sequence, P is an integer that divides N by N, "| - |" denotes an absolute value operation, "-" denotes a conjugate operation, and a timing metric M is determinedP(n) the calculation process can be divided into three steps: firstly, the received signal sequence of the initial receiving sample point{ r (N + l), l ═ 0, 1, …, N-1} and local reference sequence { x (l) }, l ═ 0, 1, …, N-1} are equally divided into P segments in the same manner, the squares of the modulo values of the cross-correlation of each segment received sequence and the corresponding local sequence are squared, and then the squares of the P modulo values are accumulated.
In one embodiment, step S210 includes steps S211 to S215 (not shown):
step S211, obtaining a preset number of buffers and a timing metric value within a preset observation range.
Step S212, selecting a preset number of timing metric values from the obtained timing metric values in the preset observation range, and respectively storing the timing metric values in the preset number of buffers.
Step S213, selecting the currently pending timing metric value from the preset observation range.
Step S214, when the minimum value in the timing metric values stored in the buffers is smaller than the currently pending timing metric value, replacing the value in the buffer corresponding to the minimum value with the currently pending timing metric value; and after the replacement or when the minimum value is larger than the currently undetermined timing metric value, returning to the step of selecting the currently undetermined timing metric value from the preset observation range until all timing metric values in the preset observation range are selected as the currently undetermined timing metric value.
Step S215, determining each timing metric value stored in each buffer as the maximum preset number of timing metric values.
Step S220, determining a preset number of candidate timing positions according to the receiving sampling point positions corresponding to the preset number of timing metric values;
wherein the reference sequence usually occurs periodically, even if it does not occur periodically, it can be assumed that the reference sequence occurs in a certain time window (with the size of N)win) Will occur at least once. Observing that the correct timing position appears at the position corresponding to the largest several metric values in the observation range with high probability due to the influence of frequency offset, and selecting the timing of the receiving sampling point n corresponding to the largest C timing metric values gamma (n) as the candidate timing position niI is 1, 2, … C, C is a positive integer.If the candidate timing position set S ═ n is defined1，n2，…，nCW ═ n |0 ≦ n for the set of all received samples in the observation window except for the candidate timing positions<NwinAnd is
Figure BDA0001599497290000053
Figure BDA0001599497290000054
The timing metric value for any one position in the set S is greater than the timing metric value for any one position in the set W.
Step S240, determining a preset number of candidate receiving sequences according to the preset number of candidate timing positions.
Wherein C candidate timing positions are obtained, for each candidate timing position niFirst, assume niCandidate received sequences are considered to be found for the correct timing position. Because there are C candidate timing positions, C candidate "candidate received sequences" are obtained, denoted as yi(n)，i＝1，2，..，C。
Step S260, determining the corresponding correlation result after the frequency offset compensation of each candidate receiving sequence.
In one embodiment, referring to fig. 2, step S260 includes steps S261 to S263:
step S261, respectively performing frequency offset estimation on each candidate receiving sequence to obtain corresponding frequency offset estimation values.
Wherein the candidate received sequence is determined by
Figure BDA0001599497290000061
Performing frequency offset estimation, the
Figure BDA0001599497290000062
Figure BDA00015994972900000612
For the frequency offset estimation value, N is the length of the candidate receiving sequence, arg { } represents the operation of taking the phase angle, N is the nth receiving sample point, Δ fIs the subcarrier spacing, yi(n) is a candidate received sequence,
Figure BDA0001599497290000063
for the conjugate of the local reference sequence, "+" indicates the conjugate operation. And selecting different modes according to different communication modes to carry out frequency offset estimation on each candidate receiving sequence.
Step S262, using the obtained frequency offset estimation values, respectively performing frequency offset compensation on the corresponding candidate receiving sequences, and obtaining candidate receiving sequences after each frequency offset compensation.
Wherein the candidate received sequence is determined by
Figure BDA0001599497290000064
The frequency offset compensation is carried out and,
Figure BDA0001599497290000065
for the frequency offset estimation, Ts＝1/fsIs the sampling interval.
Figure BDA0001599497290000066
For candidate received sequences after frequency offset compensation, yiAnd (n) is a candidate receiving sequence.
Step S263, correlate the candidate received sequences after each frequency offset compensation with the local reference sequence, respectively, to obtain each correlation result.
Wherein, candidate receiving sequence after frequency offset compensation is calculated
Figure BDA0001599497290000067
It is associated with a local reference sequence
Figure BDA0001599497290000068
The modulus of the cross-correlation of (a), i.e.:
Figure BDA0001599497290000069
obtaining C module values, and recording as gammai，i0, 1, …, C. Can also be defined as each otherSquaring of the closed mode, i.e.
Figure BDA00015994972900000610
Figure BDA00015994972900000611
Step S280, the timing metric value and the frequency deviation estimation value corresponding to the correlation result with the maximum value are determined as the final timing estimation position and the final frequency deviation estimation value.
And comparing the C module values to determine the maximum module value, wherein the timing estimation position corresponding to the maximum module value and the timing estimation position are the final timing estimation position and the final frequency deviation estimation value.
According to the synchronous detection method, a preset number of 'candidate receiving sequences' is determined according to the preset number of candidate timing positions by selecting the position corresponding to the maximum preset number of timing metric values in a preset observation range; determining a correlation result corresponding to each candidate receiving sequence; the timing measurement value and the frequency deviation estimation value corresponding to the correlation result with the maximum value are determined as the final timing estimation position and the final frequency deviation estimation value, so that the problems that the timing detection is influenced by frequency deviation, the larger the frequency deviation is, the more obvious the influence is, and the timing error is easy to occur are solved.
Referring to fig. 3, in an embodiment, initial access synchronization of an LTE (Long Term Evolution) system is used as an implementation case. The reference sequence adopted by LTE initial access is called primary Synchronization signal pss (primary Synchronization signal). In an FFD (Frequency Division Duplex) mode, a channel bandwidth is B-5 MHz (where a useful signal is 4.5MHz, and guard bands on both sides respectively account for 0.25MHz), and a sampling rate fs7.68MHz, carrier spacing Δ f 15 KHz. The PSS sequence is generated as follows:
frequency domain PSS sequence Xu(k) Based on the Zadoff-Chu sequence:
Figure BDA0001599497290000071
wherein k is not less than 0<NZC，NZC63 denotes the length of the frequency domain PSS sequence, u is the root index of Zadoff-Chu, and takes the value {25, 29, 34 }. For this implementation, the time domain PSS sequence may be generated as follows:
Figure BDA0001599497290000072
wherein n is more than or equal to 0<N-1，N＝512。xu(n) is a non-constant modulus sequence.
Step S411 to step S417 of the synchronization detection method are performed on the basis of the above:
in step S411, the timing metric calculation value Γ (n), specifically,
Figure BDA0001599497290000081
wherein:
Figure BDA0001599497290000082
r (n) represents a time domain received signal.
xu(n) is a local reference sequence, then ρu(n) is the timing metric value with root index u, and Γ (n) is the maximum ρ at different root indices (u 25, 29, 34)u(n) a timing metric value. The receiver in the LTE system does not know the specific value of u, and therefore needs to perform blind detection on it.
Step S412, selecting the timing of the reception sample point n corresponding to the C largest timing metric values Γ (n) as candidate timing positions within a certain observation range: n isi，i＝1，2，…C。
In the present embodiment, the number of candidate timing positions is set to 4, that is, C is 4. Since the PSS sequence of LTE occurs with a period of 5ms, the size of the observation time window can be defined as 5ms, and thus:
Nwin＝fs×5ms＝(7.68×106)×(5×10-3)＝38400
within the range of the observation window (n is more than or equal to 0)<Nwin-1) selecting the reception sampling point corresponding to the maximum C ═ 4 timing metric values Γ (n) as the candidate timing position niAnd i is 1, 2, 3, 4. And candidate timing position niEstimation of corresponding root number
Figure BDA0001599497290000083
The following equation is obtained:
Figure BDA0001599497290000084
in step S413, C "candidate reception sequences" are derived from the C candidate timing positions:
yi(n)，i＝1，2，..，C
and obtaining the received reference sequence according to the candidate timing position.
From step S412, C-4 candidate timing positions are obtained, for each candidate timing position niFirst, assume niFor correct timing position, i.e. to consider that a candidate received sequence y has been foundi(n)。
Since there are 4 candidate timing positions, a "candidate reception sequence" with 4 candidates is obtained, which is denoted as yi(n)，i＝1，2，3，4。
The specific implementation method for selecting the reference sequence corresponding to the 4 maximum metric values Γ (n) is as follows:
a. initialization
Using 4 buffers a1，a2，a3，a4-storing metric values for 4 candidate timing positions, the initial values of which are set to 0.
Using 4 buffers b1，b2，b3，b4-storing timing position values for 4 candidate timing positions, their initial values being set to 0.
Using 4 buffers c1，c2，c3，c4For storing 4 ones corresponding to the candidate timing positionsA candidate received sequence; the initial value is null, and the received sample index is initialized to 0, that is, n is 0.
b. 4 registers { a }1，a2，a3，a4Register of minimum value in the buffer is marked as
Figure BDA0001599497290000091
Wherein 0 is not less than imin<4. If there are a plurality of the same minimum values, any one of them may be used.
c. If it is
Figure BDA0001599497290000092
Then
Figure BDA0001599497290000093
Storing the reference sequence corresponding to the received sample point
Figure BDA0001599497290000094
d、n＝n+1。
e. If n is<NwinGo to step b), otherwise search ends, buffer { a1，a2，a3，a4The value of (b) is the maximum 4 metric values in the search range, buffer b1，b2，b3，b4The value in (f) is the candidate timing position n1，n2，n3，n4Register { c }1，c2，c3，c4Stored in the sequence is the candidate receiving sequence y1(n)，y2(n)，y3(n)，y4(n)}。
Step S414, each candidate receiving sequence yi(n) independently performing frequency offset estimation to obtain C frequency offset estimation values:
Figure BDA0001599497290000095
using each candidate received sequence y obtained in step S413i(n) independently performing frequency offset estimation to obtain C-4 frequency offset estimation values which are recorded as
Figure BDA0001599497290000096
According to one of the feasible frequency offset estimation algorithms:
Figure BDA0001599497290000101
wherein:
Figure BDA0001599497290000102
Figure BDA0001599497290000103
for the frequency offset estimation value, N is the length of the candidate receiving sequence, arg { } represents the operation of taking the phase angle, N is the nth receiving sampling point, Δ f is the subcarrier interval, y is the symbol length of the candidate receiving sequence, and the symbol length is the symbol length of the candidate receiving sequencei(n) is a candidate received sequence,
Figure BDA0001599497290000104
for the conjugate of the local reference sequence, "+" indicates the conjugate operation.
Step S415, each candidate receiving sequence yi(n) use
Figure BDA0001599497290000105
Performing frequency offset compensation to obtain C candidate receiving sequences after frequency offset compensation:
Figure BDA0001599497290000106
each candidate received sequence yi(n) use of the corresponding
Figure BDA0001599497290000107
And performing frequency offset compensation, namely:
Figure BDA0001599497290000108
wherein
Figure BDA0001599497290000109
Is the frequency deviation, T, obtained in step S414s＝1/fsIs the sampling interval. C ═ 4 candidate received sequences after frequency offset compensation, and is recorded as
Figure BDA00015994972900001010
Step S416, calculating each candidate receiving sequence after frequency offset compensation
Figure BDA00015994972900001011
It is associated with a local reference sequence
Figure BDA00015994972900001012
The cross-correlation modulus of C modulus gammai，i＝1，2，…，C。
Candidate receiving sequence after calculating frequency offset compensation
Figure BDA00015994972900001013
It is associated with a local reference sequence
Figure BDA00015994972900001014
The modulus of the cross-correlation of (a), i.e.:
Figure BDA00015994972900001015
obtaining C as 4 module values and recording as gammai，i＝1，2，3，4。
Step S417, let CiThe largest i is imaxI.e. by
Figure BDA00015994972900001016
Then the position is estimated at a fixed time
Figure BDA00015994972900001017
And frequency offset estimation
Figure BDA00015994972900001018
Respectively expressed as:
Figure BDA00015994972900001019
Figure BDA0001599497290000111
according to the synchronous detection method, a preset number of candidate receiving sequences are determined according to the preset number of candidate timing positions by selecting the position corresponding to the maximum preset number of timing metric values in a preset observation range; performing frequency offset estimation and compensation on each candidate receiving sequence; determining the correlation result of the candidate receiving sequence after each frequency offset compensation and the local reference sequence; the timing measurement value and the frequency deviation estimation value corresponding to the correlation result with the maximum value are determined as the final timing estimation position and the final frequency deviation estimation value, so that the problems that the timing detection is influenced by frequency deviation, the larger the frequency deviation is, the more obvious the influence is, and the timing error is easy to occur are solved.
Referring to fig. 4, a synchronization detecting apparatus includes:
a timing metric value obtaining module 510, configured to obtain a maximum preset number of timing metric values within a preset observation range;
wherein the timing metric value is determined by a timing metric function
Figure BDA0001599497290000112
Figure BDA0001599497290000113
Where N denotes the nth received sample, N is the length of the reference sequence, P is an integer that divides N by N, "| - |" denotes an absolute value operation, "-" denotes a conjugate operation, and a timing metric M is determinedP(n) the calculation process can be divided into three steps: firstly, a received signal sequence { r (N + l), l ═ 0, 1, …, N-1} and a local reference sequence { x (l) }, l ═ 0, 1, …, N-1} are equally divided into P segments in the same way, and then the P segments are obtainedEach segment receives the squares of the modulo values of the cross-correlation of the sequence and the corresponding local sequence and then accumulates the squares of the P modulo values.
In one embodiment, the timing metric value acquisition module 510 includes:
the device comprises a buffer and a timing metric value acquisition unit, wherein the timing metric value acquisition unit is used for acquiring the timing metric values in a preset observation range and a preset number of buffers.
And the timing storage unit is used for selecting a preset number of timing metric values from the acquired timing metric values in the preset observation range and respectively storing the timing metric values in the preset number of buffers.
And the currently undetermined timing metric value selecting unit is used for selecting the currently undetermined timing metric value from a preset observation range.
The timing metric value judging unit is used for replacing the value in the buffer corresponding to the minimum value with the currently undetermined timing metric value when the minimum value in the timing metric values stored in the buffers is smaller than the currently undetermined timing metric value; and after the replacement or when the minimum value is larger than the currently undetermined timing metric value, returning to the step of selecting the currently undetermined timing metric value from the preset observation range until all timing metric values in the preset observation range are selected as the currently undetermined timing metric value.
And the maximum timing metric value determining unit is used for determining each timing metric value stored in each buffer as the maximum preset number of timing metric values.
A candidate timing position determining module 520, configured to determine a preset number of candidate timing positions according to the receiving sampling point positions corresponding to the preset number of timing metric values.
Wherein the reference sequence usually occurs periodically, even if it does not occur periodically, it can be assumed that the reference sequence occurs in a certain time window (with the size of N)win) Will occur at least once. Observing that the correct timing position appears at the position corresponding to the largest several metric values in the observation range with high probability due to the influence of frequency offset, and selecting the timing of the receiving sampling point n corresponding to the largest C timing metric values gamma (n) as the candidate timing position ni，i＝1，2，…C and C are positive integers. If the candidate timing position set S ═ n is defined1，n2，…，ncW ═ n |0 ≦ n for the set of all received samples in the observation window except for the candidate timing positions<NwinAnd is
Figure BDA0001599497290000121
Figure BDA0001599497290000122
The timing metric value for any one position in the set S is greater than the timing metric value for any one position in the set W.
A candidate receiving sequence determining module 540, configured to determine a preset number of candidate receiving sequences according to the preset number of candidate timing positions.
Wherein C candidate timing positions are obtained, for each candidate timing position niFirst, assume niCandidate received sequences are considered to be found for the correct timing position. Because there are C candidate timing positions, C candidate "candidate received sequences" are obtained, denoted as yi(n)，i＝1，2，..，C。
And a frequency offset compensation and correlation result determining module 560, configured to determine a corresponding correlation result after the frequency offset compensation is performed on each candidate receiving sequence.
In one embodiment, the frequency offset compensation and correlation result determination module 560 includes:
and the frequency offset estimation value unit is used for respectively carrying out frequency offset estimation on each candidate receiving sequence to obtain a corresponding frequency offset estimation value.
And the frequency offset compensation unit is used for respectively carrying out frequency offset compensation on the corresponding candidate receiving sequences by adopting the obtained frequency offset estimation values to obtain the candidate receiving sequences after each frequency offset compensation.
And the correlation result determining unit is used for correlating the candidate receiving sequences after each frequency offset compensation with the local reference sequence respectively to obtain each correlation result.
A final timing estimation position and final frequency offset estimation value determining module 580, configured to determine the timing metric value and the frequency offset estimation value corresponding to the maximum correlation result as a final timing estimation position and a final frequency offset estimation value.
And comparing the C module values to determine the maximum module value, wherein the timing estimation position corresponding to the maximum module value and the timing estimation position are the final timing estimation position and the final frequency deviation estimation value.
The synchronous detection device determines a preset number of candidate receiving sequences according to the preset number of candidate timing positions by selecting the position corresponding to the maximum preset number of timing metric values in a preset observation range; determining a correlation result corresponding to each candidate receiving sequence; the timing measurement value and the frequency deviation estimation value corresponding to the correlation result with the maximum value are determined as the final timing estimation position and the final frequency deviation estimation value, so that the problems that the timing detection is influenced by frequency deviation, the larger the frequency deviation is, the more obvious the influence is, and the timing error is easy to occur are solved.
In one embodiment, there is also provided a communication-capable device including a memory, a processor, and a communication-capable device stored on the memory and operable on the processor, wherein the processor executes the program to implement any one of the synchronization detection methods in the embodiments.
When a processor of the device with the communication capability executes a program, the correct timing position is selected through the steps according to the position corresponding to the maximum preset number of timing measurement values in the preset observation range, so that the problem that timing detection is influenced by frequency deviation, the larger the frequency deviation is, the more obvious the influence is, and timing errors are easy to occur is solved.
In addition, it can be understood by those skilled in the art that all or part of the processes in the methods of the embodiments described above can be implemented by instructing the relevant hardware through a computer program, where the program can be stored in a non-volatile computer-readable storage medium, and as in the embodiments of the present application, the program can be stored in the storage medium of the computer system and executed by at least one processor in the computer system, so as to implement the processes including the embodiments of the synchronization detection methods described above.
In one embodiment, there is also provided a storage medium having stored thereon a computer program,
wherein, when being executed by a processor, the program implements any one of the synchronization detection methods in the embodiments. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.
The computer storage medium and the computer program stored in the computer storage medium realize the processes of the embodiments of the synchronous detection methods, so that the correct timing position can be selected through the steps according to the position corresponding to the maximum preset number of timing metric values in the preset observation range, and the problems that the timing detection is influenced by frequency deviation, the larger the frequency deviation is, the more obvious the influence is and the timing error is easy to occur are solved.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A synchronization detection method, comprising:
acquiring a maximum preset number of timing metric values in a preset observation range;
determining a preset number of candidate timing positions according to the receiving sampling point positions corresponding to the preset number of timing metric values;
determining a preset number of candidate receiving sequences according to the preset number of candidate timing positions;
determining a corresponding correlation result after frequency offset compensation of each candidate receiving sequence;
determining a timing metric value and a frequency deviation estimation value corresponding to the correlation result with the maximum value as a final timing estimation position and a final frequency deviation estimation value;
the step of determining the correlation result corresponding to each candidate receiving sequence after frequency offset compensation comprises:
respectively carrying out frequency offset estimation on each candidate receiving sequence to obtain corresponding frequency offset estimation values;
respectively carrying out frequency offset compensation on the corresponding candidate receiving sequences by adopting the obtained frequency offset estimation values to obtain candidate receiving sequences after each frequency offset compensation;
and respectively correlating the candidate receiving sequences after each frequency offset compensation with the local reference sequence to obtain each correlation result.
2. The synchronization detection method of claim 1, wherein the correlation result comprises a cross-correlation modulus or a square of the cross-correlation modulus.
3. The synchronous detection method according to claim 1 or 2, wherein determining the timing metric value and the frequency offset estimation value corresponding to the correlation result with the largest value as the final timing estimation position and the final frequency offset estimation value comprises:
determining a correlation result having a maximum value by comparing the correlation results;
and determining the timing metric value and the frequency deviation estimation value corresponding to the correlation result with the maximum value as a final timing estimation position and a final frequency deviation estimation value.
4. The synchronization detection method according to claim 1, wherein the step of obtaining a maximum preset number of timing metric values within a preset observation range comprises:
acquiring a timing metric value in a preset observation range;
selecting a preset number of timing metric values from the obtained timing metric values in a preset observation range, and respectively storing the timing metric values in the preset number of buffers;
selecting a currently undetermined timing metric value from a preset observation range;
when the minimum value in the timing metric values stored in the buffers is smaller than the currently pending timing metric value, replacing the value in the buffer corresponding to the minimum value with the currently pending timing metric value; and after the replacement or when the minimum value is larger than the currently undetermined timing metric value, returning to the step of selecting the currently undetermined timing metric value from the preset observation range until all timing metric values in the preset observation range are selected as the currently undetermined timing metric value;
and determining each timing metric value stored in each buffer as the maximum preset number of timing metric values.
5. The sync detection method of claim 1, wherein the candidate received sequence is passed through
Figure FDA0002823599450000021
Performing frequency offset estimation, the
Figure FDA0002823599450000022
Figure FDA0002823599450000023
For the frequency offset estimation value, N is the length of the candidate receiving sequence, arg { } represents the operation of taking the phase angle, N is the nth receiving sampling point, Δ f is the subcarrier interval, y is the symbol length of the candidate receiving sequence, and the symbol length is the symbol length of the candidate receiving sequencei(n) is a candidate received sequence,
Figure FDA0002823599450000024
for the conjugate of the local reference sequence, "+" indicates the conjugate operation.
6. The sync detection method of claim 1, wherein the candidate received sequence is passed through
Figure FDA0002823599450000025
The frequency offset compensation is carried out and,
Figure FDA0002823599450000026
for the frequency offset estimation, Ts＝1/fsIs the sampling interval;
Figure FDA0002823599450000027
for candidate received sequences after frequency offset compensation, yiAnd (n) is a candidate receiving sequence.
7. A synchronization detection apparatus, comprising:
the timing metric value acquisition module is used for acquiring the maximum preset number of timing metric values in a preset observation range;
a candidate timing position determining module, configured to determine a preset number of candidate timing positions according to the receiving sampling point positions corresponding to the preset number of timing metric values;
a candidate receiving sequence determining module, configured to determine a preset number of candidate receiving sequences according to the preset number of candidate timing positions;
the frequency offset compensation and correlation result determining module is used for determining the corresponding correlation result after the frequency offset compensation is carried out on each candidate receiving sequence;
a final timing estimation position and final frequency deviation estimation value determining module, configured to determine a timing metric value and a frequency deviation estimation value corresponding to a maximum correlation result as a final timing estimation position and a final frequency deviation estimation value; the frequency offset compensation and correlation result determination module comprises:
the frequency offset estimation value unit is used for respectively carrying out frequency offset estimation on each candidate receiving sequence to obtain corresponding frequency offset estimation values;
the frequency offset compensation unit is used for respectively carrying out frequency offset compensation on the corresponding candidate receiving sequences by adopting the obtained frequency offset estimation values to obtain the candidate receiving sequences after each frequency offset compensation;
and the correlation result determining unit is used for correlating the candidate receiving sequences after each frequency offset compensation with the local reference sequence respectively to obtain each correlation result.
8. The synchronization detection apparatus according to claim 7, wherein the correlation result determination unit is further configured to determine a correlation result having a maximum value by comparing the correlation results; and determining the timing metric value and the frequency deviation estimation value corresponding to the correlation result with the maximum value as a final timing estimation position and a final frequency deviation estimation value.
9. A device with communication capabilities, comprising a memory, a processor and a computer program stored on said memory and executable on said processor, characterized in that said processor implements the synchronization detection method according to any of claims 1 to 6 when performing a time synchronization.
10. A storage medium on which a computer program is stored which, when being executed by a processor, carries out the synchronization detection method according to any one of claims 1 to 6.
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