CN113938367A - SC-FDE system frequency offset estimation method using phase difference successive approximation - Google Patents

SC-FDE system frequency offset estimation method using phase difference successive approximation Download PDF

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CN113938367A
CN113938367A CN202111158115.XA CN202111158115A CN113938367A CN 113938367 A CN113938367 A CN 113938367A CN 202111158115 A CN202111158115 A CN 202111158115A CN 113938367 A CN113938367 A CN 113938367A
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frequency offset
phase difference
sequences
symbol
sequence
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CN113938367B (en
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王博阳
周升国
黄鏐
曹元将
吕卫祥
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724th Research Institute of CSIC
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2657—Carrier synchronisation
    • H04L27/2659—Coarse or integer frequency offset determination and synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2662—Symbol synchronisation
    • H04L27/2663—Coarse synchronisation, e.g. by correlation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
    • H04L27/2692—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with preamble design, i.e. with negotiation of the synchronisation sequence with transmitter or sequence linked to the algorithm used at the receiver

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Abstract

The invention discloses a frequency offset estimation method of an SC-FDE system by utilizing phase difference successive approximation, and relates to the technical field of broadband wireless communication. The method comprises the following steps: first, for the received signal S0The preamble training sequence carries out coarse frequency deviation estimation to obtain a carrier frequency deviation estimation value
Figure DDA0003289080390000011
Then, for the obtained received signal S0Performing a frequency offset correction to obtain a signal S1(ii) a Calculating frequency offset by using phase difference of two UW sequences in Nth symbol
Figure DDA0003289080390000012
Utilizing the UW sequence formed by combining the Nth symbol and the (N-1) th symbol, sequentially carrying out correlation operation on the first N-2 combined UW sequences to obtain the phase difference among the sequences, and calculating N-2 frequency offset arrays according to the phase difference
Figure DDA0003289080390000013
Wherein i is more than or equal to 1 and less than or equal to N-2; finally, through comparison, a proper frequency offset value is obtained for frequency offset estimation. The method effectively improves the estimation precision of the carrier frequency offset.

Description

SC-FDE system frequency offset estimation method using phase difference successive approximation
Technical Field
The invention relates to the technical field of broadband wireless communication.
Background
With the improvement of the scientific and technical level, the technology in the communication field is also rapidly developed, and the fourth generation mobile communication taking the OFDM as the key technology has gone into people's lives. With the development of wireless communication technology, new technical problems are also beginning to arise. For example, the signal is blocked by buildings, walls and other objects on the propagation path, and reflection, diffraction and scattering phenomena occur, which causes the received signal to be a superposition of multiple paths of different delay signals, i.e. the channel has multipath fading, which seriously affects the propagation of the signal.
In response to these problems, studies have resulted in the SC-FDE method. SC-FDE is a very effective method to combat multipath effects in broadband wireless communications. In the SC-FDE system, there is a carrier frequency offset at the transmitting and receiving ends, which is mainly caused by the finite stability between the receiver crystal oscillator and the transmitter crystal oscillator, and other reasons are caused by the doppler effect under motion conditions. After the signal is transformed into the frequency domain by the FFT, the carrier frequency offset is equal to the inter-carrier interference ICI, and after the signal is transformed into the time domain by the IFFT, the received signal still has constellation point offset, which affects symbol decision and causes an increase in bit error rate, so that the carrier frequency offset needs to be estimated and tracked.
Most of the existing solutions to this problem use only preamble sequences to perform frequency offset estimation, and this estimation algorithm has a large error, and is especially obvious when the frame length is long and a fast time-varying multipath channel is encountered.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides an SC-FDE system frequency offset estimation method by utilizing phase difference successive approximation, which is realized by the following technical scheme:
two identical leader sequences are arranged at the head of a signal and used for coarse carrier synchronization, wherein the head and the tail of each symbol have two identical UW sequences, the UW sequences in each symbol are consistent, and accurate carrier frequency estimation is carried out by using the phase difference of the UW sequences between the symbols, which comprises the following steps:
step 1: by receptionSignal S0The preamble training sequence carries out coarse frequency deviation estimation to obtain a carrier frequency deviation estimation value
Figure RE-GDA0003374679290000011
Step 2: for received signal S0Performing a frequency offset correction to obtain a signal S1；
And step 3: for signal S1The Nth symbol uses the phase difference of two UW sequences inside the Nth symbol to calculate the frequency offset
Figure RE-GDA0003374679290000012
And 4, step 4: combining head and tail adjacent UW sequences between adjacent symbols to generate N-1 combined sequences, using the UW sequence formed by combining the Nth symbol and the N-1 th symbol, sequentially carrying out correlation operation on the first N-2 combined UW sequences to obtain phase difference between the sequences, and calculating N-2 frequency offset arrays according to the phase difference
Figure RE-GDA0003374679290000013
Wherein i is more than or equal to 1 and less than or equal to N-2;
and 5: will array
Figure RE-GDA0003374679290000021
A value of
Figure RE-GDA0003374679290000022
Subtracting, and obtaining the difference value delta fs(i) Arranging according to the numbering sequence of the symbols, and calculating the maximum frequency error f according to the sequence of the numbers from large to small and the theoryΔmax(i) Comparing;
step 6: in the process of comparing in sequence, when the maximum frequency error f is obtainedΔmax(i) When the difference value is within the range, stopping comparison, and taking the frequency offset value in the corresponding frequency offset array to correct the current symbol frequency offset; if all the difference values are larger than the maximum frequency error, the difference value calculated in the step 3 is taken
Figure RE-GDA0003374679290000023
And correcting the frequency offset of the current symbol.
Compared with the prior art, the invention has the following remarkable advantages:
1. compared with a method for performing coarse frequency offset estimation only by using a leader sequence, the method performs accurate frequency offset estimation by using the phase difference of UW between symbols, and the frequency offset estimation precision is improved better.
2. Under the condition of longer frame length, the robust frequency offset estimation precision can still be maintained.
3. Removing deviations f greater than a maximum frequencyΔmax(i) The final frequency offset estimation precision is not deteriorated due to frequency offset mutation or other conditions.
The present invention is described in further detail below with reference to the attached drawings.
Drawings
FIG. 1 is a schematic diagram of the data processing flow of the present invention.
Fig. 2 is a schematic diagram of a frame structure of a communication signal in the present invention.
FIG. 3 is a schematic diagram of the implementation of step 6 in the present invention.
Detailed Description
The invention is further described with reference to the accompanying drawings, but the scope of protection of the invention is not limited by the embodiments. The frequency offset estimation method of the SC-FDE system using phase difference successive approximation according to the present invention is described with reference to fig. 1.
As shown in FIG. 1, the present invention comprises the following steps:
step 1: using received signals S0The preamble training sequence carries out coarse frequency deviation estimation to obtain a carrier frequency deviation estimation value
Figure RE-GDA0003374679290000024
Preferably, wherein the signal S is received0Can be described as:
Figure RE-GDA0003374679290000027
a (t) represents a modulation signal, f0Representing the carrier frequency.
Step 2: for received signal S0Performing a frequency offset correction to obtain a signal S1；
Preferably, the modified signal S1Can be described specifically as:
Figure RE-GDA0003374679290000025
where af represents the assumed true carrier frequency offset,
Figure RE-GDA0003374679290000026
representing the estimated carrier frequency offset value.
And step 3: for signal S1The Nth symbol uses the phase difference of two UW sequences inside the Nth symbol to calculate the frequency offset
Figure RE-GDA0003374679290000031
Preferably, the method for calculating the phase difference between two UW sequences inside a symbol is a correlation method, which can be specifically described as follows:
Figure RE-GDA0003374679290000032
where Δ φ represents the phase difference of the two UW sequences, L is the length of the UW sequence, and x (N) represents the UW sequence in the Nth symbol.
And 4, step 4: combining head and tail adjacent UW sequences between adjacent symbols to generate N-1 combined sequences, using the UW sequence formed by combining the Nth symbol and the N-1 th symbol, sequentially carrying out correlation operation on the first N-2 combined UW sequences to obtain phase difference between the sequences, and calculating N-2 frequency offset arrays according to the phase difference
Figure RE-GDA0003374679290000033
Wherein i is more than or equal to 1 and less than or equal to N-2;
preferably, the method for calculating the phase difference between two combined UW sequences between symbols is a correlation method, which can be specifically described as follows:
Figure RE-GDA0003374679290000034
wherein
Figure RE-GDA0003374679290000035
Represents the phase difference of two UW sequences, 2L is the length of the combined UW sequence, y (N) represents the UW sequence formed by combining the Nth symbol with the N-1 th symbol, and z (N) represents the first N-2 combined UW sequences.
And 5: will array
Figure RE-GDA0003374679290000036
A value of
Figure RE-GDA0003374679290000037
Subtracting, and obtaining the difference value delta fs(i) Arranging according to the numbering sequence of the symbols, and calculating the maximum frequency error f according to the sequence of the numbers from large to small and the theoryΔmax(i) Comparing;
preferably, the maximum frequency error can be specifically described as:
Figure RE-GDA0003374679290000038
wherein f isΔmax(i) Represents the maximum frequency error, DiRepresenting the signal delay, TsRepresenting the sampling period.
Step 6: in the process of comparing in sequence, when the maximum frequency error f is obtainedΔmax(i) When the difference value is within the range, stopping comparison, and taking the frequency offset value in the corresponding frequency offset array to correct the current symbol frequency offset; if all the difference values are larger than the maximum frequency error, the difference value calculated in the step 3 is taken
Figure RE-GDA0003374679290000039
And correcting the frequency offset of the current symbol.
As is clear from FIG. 3, D of the parameter is obtained with the process of comparisoniThe value is gradually increased while fΔmax(i) The error range is gradually reduced. During the initial comparison, the value is estimated
Figure RE-GDA00033746792900000310
Will be greater than corresponding fΔmax(1) And fΔmax(2). But will appear at f as the value of D increasesΔmax(i) Within the range of
Figure RE-GDA00033746792900000311
Thereby obtaining an accurate frequency offset estimation value.

Claims (7)

1. The method for estimating the frequency offset of the SC-FDE system by utilizing the successive approximation of the phase difference is characterized by comprising the following steps: the signal head has two identical preamble sequences for carrier coarse synchronization, and assuming that there are N symbols in the signal, there are two identical UW sequences in the head and tail of each symbol, and the UW sequences in each symbol are identical, including:
step 1: using received signals S0The preamble training sequence carries out coarse frequency deviation estimation to obtain a carrier frequency deviation estimation value
Figure FDA0003289080360000011
Step 2: for received signal S0Performing a frequency offset correction to obtain a signal S1；
And step 3: for signal S1The Nth symbol uses the phase difference of two UW sequences inside the Nth symbol to calculate the frequency offset
Figure FDA0003289080360000012
And 4, step 4: combining head and tail adjacent UW sequences among adjacent symbols to generate N-1 combined sequences, and sequentially combining the first N-2 combined sequences by using the UW sequence formed by combining the Nth symbol and the N-1 th symbolPerforming correlation operation on the UW sequence to obtain phase difference between the sequences, and calculating N-2 frequency offset arrays according to the phase difference
Figure FDA0003289080360000013
Wherein i is more than or equal to 1 and less than or equal to N-2;
and 5: will array
Figure FDA0003289080360000014
A value of
Figure FDA0003289080360000015
Subtracting the difference value delta fs(i) Arranging according to the numbering sequence of the symbols, and calculating the maximum frequency error f according to the sequence of the numbers from large to small and the theory△max(i) Comparing;
step 6: in the process of comparing in sequence, when the maximum frequency error f is obtained△max(i) When the difference value is within the range, stopping comparison, and taking the frequency offset value in the corresponding frequency offset array to correct the current symbol frequency offset; if all the difference values are larger than the maximum frequency error, the difference value calculated in the step 3 is taken
Figure FDA0003289080360000016
And correcting the frequency offset of the current symbol.
2. The method for estimating frequency offset of an SC-FDE system using successive approximation of phase differences as claimed in claim 1, wherein: the received signal S in step 10The method comprises the following steps:
Figure FDA0003289080360000017
wherein a (t) represents a modulation signal, f0Representing the carrier frequency.
3. The method of estimating frequency offset of SC-FDE system using successive approximation of phase difference as claimed in claim 1, whereinIs characterized in that: the coarse frequency offset estimation method in step 1 is to perform correlation operation on two same leader sequences of the signal head to obtain a phase difference epsilon, and to obtain a coarse frequency offset estimation value according to the phase difference epsilon
Figure FDA0003289080360000018
4. The method of estimating frequency offset of SC-FDE system using successive approximation of phase difference according to claim 1, wherein: the modified signal S in step 21The method comprises the following steps:
Figure FDA0003289080360000019
wherein f is0Representing the carrier frequency, af represents the assumed true carrier frequency offset,
Figure FDA00032890803600000110
representing the estimated carrier frequency offset value.
5. The method of estimating frequency offset of SC-FDE system using successive approximation of phase difference according to claim 1, wherein: the method for calculating the phase difference between two UW sequences in the symbol in the step 3 is a correlation method, and comprises the following steps:
Figure FDA0003289080360000021
where Δ φ represents the phase difference of the two UW sequences, L is the length of the UW sequence, and x (N) represents the UW sequence in the Nth symbol.
6. The method of estimating frequency offset of SC-FDE system using successive approximation of phase difference as claimed in claim 1, wherein: the method for calculating the phase difference between the two combined UW sequences in step 4 is a correlation method, and includes:
Figure FDA0003289080360000022
wherein
Figure FDA0003289080360000023
Represents the phase difference of two UW sequences, 2L is the length of the combined UW sequence, y (N) represents the UW sequence formed by combining the Nth symbol with the N-1 th symbol, and z (N) represents the first N-2 combined UW sequences.
7. The method of estimating frequency offset of SC-FDE system using successive approximation of phase difference according to claim 1, wherein: the maximum frequency error in step 5 includes:
Figure FDA0003289080360000024
wherein f is△max(i) Represents the maximum frequency error, DiRepresenting the signal delay, TsRepresents a sampling period; as the comparison progresses, the parameter DiGradually increasing with f△max(i) The value of (a) is continuously reduced, namely the error range is gradually reduced; the estimation accuracy is improved by successive comparisons.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1739911A2 (en) * 2005-06-30 2007-01-03 NTT DoCoMo Inc. A training sequence generating method, a communication system and communication method
CN103095613A (en) * 2013-01-21 2013-05-08 西安电子科技大学 Integer frequency doubling offset and channel parameter joint estimation algorithm with ultra-low complexity in single carrier frequency domain equalization (SC-FDE) system
US20160183211A1 (en) * 2013-08-21 2016-06-23 Nec Corporation Frequency deviation compensation scheme, frequency deviation compensation method, and storage medium
CN106789791A (en) * 2017-02-28 2017-05-31 北京科技大学 GSM carrier frequency bias estimation based on conjugation symmetric training sequence
CN107426123A (en) * 2017-07-17 2017-12-01 北京睿信丰科技有限公司 One kind carries out joint integer frequency bias method of estimation and device using more intersymbol pilot tones
CN111756663A (en) * 2020-05-20 2020-10-09 深圳市科思科技股份有限公司 Frequency offset estimation method, device, equipment and computer readable storage medium
CN112565142A (en) * 2020-11-06 2021-03-26 北京遥测技术研究所 Multi-mode SC-FDE burst transmission carrier synchronization method

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1739911A2 (en) * 2005-06-30 2007-01-03 NTT DoCoMo Inc. A training sequence generating method, a communication system and communication method
CN103095613A (en) * 2013-01-21 2013-05-08 西安电子科技大学 Integer frequency doubling offset and channel parameter joint estimation algorithm with ultra-low complexity in single carrier frequency domain equalization (SC-FDE) system
US20160183211A1 (en) * 2013-08-21 2016-06-23 Nec Corporation Frequency deviation compensation scheme, frequency deviation compensation method, and storage medium
CN106789791A (en) * 2017-02-28 2017-05-31 北京科技大学 GSM carrier frequency bias estimation based on conjugation symmetric training sequence
CN107426123A (en) * 2017-07-17 2017-12-01 北京睿信丰科技有限公司 One kind carries out joint integer frequency bias method of estimation and device using more intersymbol pilot tones
CN111756663A (en) * 2020-05-20 2020-10-09 深圳市科思科技股份有限公司 Frequency offset estimation method, device, equipment and computer readable storage medium
CN112565142A (en) * 2020-11-06 2021-03-26 北京遥测技术研究所 Multi-mode SC-FDE burst transmission carrier synchronization method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
凌琪琪;罗志年;: "基于数据相关叠加训练序列的载波频偏与信道联合估计", 计算机工程, no. 09 *

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