CN102130880A

CN102130880A - Method and system for correcting frequency offset estimation in OFDM system

Info

Publication number: CN102130880A
Application number: CN2011100699120A
Authority: CN
Inventors: 萧少宁; 韩健
Original assignee: ZTE Corp
Current assignee: Sanechips Technology Co Ltd
Priority date: 2011-03-22
Filing date: 2011-03-22
Publication date: 2011-07-20
Anticipated expiration: 2031-03-22
Also published as: WO2012126233A1; CN102130880B

Abstract

The invention discloses a method for correcting frequency offset estimation in an orthogonal frequency division multiplexing access (OFDMA) system. The method comprises the following steps of: estimating channel estimation values of two time slots according to a reference signal which is generated at a transmitting end and a reference signal which is generated at a receiving end, and obtaining an initial frequency offset estimated value according to the channel estimation values of the two time slots; and correcting the channel estimation values of the two time slots to obtain a frequency offset estimation corrected value according to an interference matrix between sub-carriers in the process of correcting the initial frequency offset estimated value. The invention also discloses a system for correcting frequency offset estimation in the OFDMA system. An initial frequency offset estimated value correction unit in the system is used for correcting the channel estimation values of the two time slots to obtain the frequency offset estimation corrected value according to the interference matrix between sub-carriers in the process of correcting the initial frequency offset estimated value. The method and the system improve the frequency offset estimation accuracy.

Description

Correction method and system for frequency offset estimation of OFDMA system

Technical Field

The present invention relates to a Frequency offset correction technology, and in particular, to a method and a system for correcting Frequency offset estimation of an Orthogonal Frequency Division Multiple Access (OFDMA) system.

Background

In the OFDMA system, due to the crystal oscillator deviation and the influence of spatial doppler shift, frequency offset of subcarriers may be generated, and therefore, a reference signal needs to be used at a receiving end for frequency offset estimation, however, in the prior art, a frequency offset estimation method performed only according to the reference signal is not accurate, and since accurate frequency offset estimation can effectively correct the influence of frequency offset on channel estimation, it is necessary to improve the accuracy of frequency offset estimation.

Disclosure of Invention

In view of the above, the main objective of the present invention is to provide a method and a system for correcting frequency offset estimation of an OFDMA system, which can accurately estimate frequency offset estimation values in various channel environments, thereby improving the accuracy of frequency offset estimation.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a method for correcting frequency offset estimation of an OFDMA system comprises the following steps:

after passing through a channel, a reference signal generated by a transmitting end of an Orthogonal Frequency Division Multiple Access (OFDMA) system is subjected to Orthogonal Frequency Division (OFDM) demodulation at a receiving end, and the receiving end extracts the received reference signal;

estimating channel estimation values of two time slots according to a reference signal generated by a transmitting end and a reference signal received by a receiving end, and obtaining an initial frequency offset estimation value according to the channel estimation values of the two time slots;

when the initial frequency offset estimation value is corrected, the channel estimation values of the two time slots are corrected according to the inter-subcarrier interference matrix to obtain a frequency offset estimation correction value.

Wherein, obtaining the initial frequency offset estimation value according to the channel estimation values of the two time slots specifically comprises: and obtaining a phase difference according to the channel estimation values of the two time slots, and calculating an initial frequency offset estimation value according to the phase difference.

Wherein, the obtaining of the frequency offset estimation correction value after correcting the channel estimation values of the two time slots according to the inter-subcarrier interference matrix specifically includes: when the initial frequency offset estimation value is corrected, calculating an inter-subcarrier interference matrix, obtaining new channel estimation values of two time slots according to the inter-subcarrier interference matrix and a reference signal received by the receiving end, obtaining a phase difference according to the new channel estimation values of the two time slots, and calculating a frequency offset estimation correction value according to the phase difference.

Wherein, the inter-subcarrier interference matrix is specifically a (γ), and the adopted calculation formula is as follows:

wherein, when the number of the current sub-carriers is k, w_-3Interference coefficient of sub-carrier of k-3, w_-2Interference coefficient of sub-carrier of k-2, w_-1Interference coefficient of sub-carrier of k-1, w₀For the interference coefficient of the current subcarrier, w₁Interference coefficient of sub-carrier of k +1 th, w₂Interference coefficient of sub-carrier of k +2 th, w₃The interference coefficient of the k +3 th subcarrier is γ, and the frequency offset value is γ.

Wherein, the w_-3W to_-2W to_-1W to₀W to₁W to₂And said w₃The calculation formulas adopted respectively are specifically as follows:

w_-3＝exp(-jπ*(-3)/N)/(N*sin(π*(-3+γ)/N))*β；

w_-2＝exp(-jπ*(-2)/N)/(N*sin(π*(-2+γ)/N))*β；

w_-1＝exp(-jπ*(-1)/N)/(N*sin(π*(-1+γ)/N))*β；

w₀＝exp(-jπ*(0)/N)/(N*sin(π*(0+γ)/N))*β；

w₁＝exp(-jπ*(1)/N)/(N*sin(π*(1+γ)/N))*β；

w₂＝exp(-jπ*(2)/N)/(N*sin(π*(2+γ)/N))*β；

w₃＝exp(-jπ*(3)/N)/(N*sin(π*(3+γ)/N))*β；

wherein,

-freq _ offset/Δ f; the beta is a coefficient of frequency offset; the freq _ offset/delta f is an initial frequency offset estimation value, and delta f is a frequency interval between subcarriers; n is the number of sampling points determined by the bandwidth of the OFDMA system, j is an imaginary unit, j²＝-1。

A system for correcting frequency offset estimation in an OFDMA system, the system comprising: a demodulation and initial frequency offset estimation unit and an initial frequency offset estimation correction unit; wherein,

the demodulation and initial frequency offset estimation unit is used for OFDM demodulation at a receiving end after a reference signal generated by an OFDMA system transmitting end passes through a channel, and the receiving end extracts the received reference signal; estimating channel estimation values of two time slots according to a reference signal generated by a transmitting end and a reference signal received by a receiving end, and obtaining an initial frequency offset estimation value according to the channel estimation values of the two time slots;

and the initial frequency offset estimation correction unit is used for correcting the initial frequency offset estimation value according to the inter-subcarrier interference matrix to obtain a frequency offset estimation correction value after correcting the channel estimation values of the two time slots.

The demodulation and initial frequency offset estimation unit is further configured to, under the condition of calculating an initial frequency offset estimation value, obtain a phase difference according to channel estimation values of two time slots, and calculate the initial frequency offset estimation value according to the phase difference.

The initial frequency offset estimation and correction unit is further configured to calculate an inter-subcarrier interference matrix when correcting the initial frequency offset estimation value under the condition that the frequency offset estimation correction value is obtained after correcting the channel estimation values of the two time slots according to the inter-subcarrier interference matrix, obtain new channel estimation values of the two time slots according to the inter-subcarrier interference matrix and a reference signal received by the receiving end, obtain a phase difference according to the new channel estimation values of the two time slots, and calculate the frequency offset estimation correction value according to the phase difference.

Wherein, the initial frequency offset estimation and correction unit is further configured to, when the inter-subcarrier interference matrix is specifically a (γ), use the following calculation formula:

Wherein the initial frequency offset estimation correction unit is further used for calculating the w_-3W to_-2W to_-1W to₀W to₁W to₂And said w₃In time, the calculation formulas adopted respectively are specifically as follows:

w_-3＝exp(-jπ*(-3)/N)/(N*sin(π*(-3+γ)/N))*β；

w_-2＝exp(-jπ*(-2)/N)/(N*sin(π*(-2+γ)/N))*β；

w_-1＝exp(-jπ*(-1)/N)/(N*sin(π*(-1+γ)/N))*β；

w₀＝exp(-jπ*(0)/N)/(N*sin(π*(0+γ)/N))*β；

w₁＝exp(-jπ*(1)/N)/(N*sin(π*(1+γ)/N))*β；

w₂＝exp(-jπ*(2)/N)/(N*sin(π*(2+γ)/N))*β；

w₃＝exp(-jπ*(3)/N)/(N*sin(π*(3+γ)/N))*β；

wherein,

The reference signal generated by the transmitting end of the OFDMA system is subjected to Orthogonal Frequency Division (OFDM) demodulation at the receiving end after passing through a channel, and the receiving end extracts the received reference signal; estimating channel estimation values of two time slots according to a reference signal generated by a transmitting end and a reference signal received by a receiving end, and obtaining an initial frequency offset estimation value according to the channel estimation values of the two time slots; when the initial frequency offset estimation value is corrected, the channel estimation values of the two time slots are corrected according to the inter-subcarrier interference matrix to obtain a frequency offset estimation correction value.

By adopting the method and the device, the frequency offset estimation correction value is obtained by introducing the inter-subcarrier interference matrix and correcting the channel estimation values of the two time slots according to the inter-subcarrier interference matrix, the frequency offset estimation values under various channel environments can be accurately estimated, and the accuracy of frequency offset estimation is improved.

Drawings

Fig. 1 is a schematic diagram of a flow chart of implementing frequency offset correction according to an embodiment of the present invention.

Detailed Description

The basic idea of the invention is: by introducing the inter-subcarrier interference matrix and correcting the channel estimation values of the two time slots according to the inter-subcarrier interference matrix to obtain a frequency offset estimation correction value, the frequency offset estimation values under various channel environments can be accurately estimated, and therefore the accuracy of frequency offset estimation is improved.

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

A correction method for frequency offset estimation of OFDMA system mainly includes the following steps:

after passing through a channel, a reference signal generated by an OFDMA system transmitting end is subjected to OFDM demodulation at a receiving end, and the receiving end extracts the received reference signal; estimating channel estimation values of two time slots according to a reference signal generated by a transmitting end and a reference signal received by a receiving end, and obtaining an initial frequency offset estimation value according to the channel estimation values of the two time slots; when the initial frequency offset estimation value is corrected, the channel estimation values of the two time slots are corrected according to the inter-subcarrier interference matrix to obtain a frequency offset estimation correction value. The frequency offset estimation correction value is a frequency offset estimation correction value finally obtained after the initial frequency offset estimation value is corrected.

Further, the estimating channel estimation values of two time slots according to the reference signal generated by the transmitting end and the reference signal received by the receiving end, and obtaining the initial frequency offset estimation value according to the channel estimation values of the two time slots specifically includes:

a1, after the reference signal reference generated by the OFDMA system transmitting end passes through the channel, OFDM demodulation is carried out at the receiving end, and then the reference signal receive _ reference is extracted. For reference, 2 reference signals are actually transmitted in one subframe, that is, the reference value is 2; for the receive _ reference, 2 reference signals are actually received in one subframe, that is, the value of the receive _ reference is 2, which is different from the value of the reference. In addition, the local signal of the receiving end also includes a local reference signal with the same value as the reference, that is, the local reference signal is also 2 and has the same value as the reference.

a2, selecting a proper Resource Block (RB), adopting the existing channel estimation method of the OFDM system, and estimating channel estimation values of two time slots, namely h and h', according to a receive _ reference and a reference. Wherein, for the calculation methods of h and h', if 2 references have values of A1 and A2; let the values of 2 receive _ references be B1, B2, respectively; let the receiving end and the local reference signal with the same value as reference, the values of 2 local reference signals are respectively C1-a 1 and C2-a 2; then h is B1-C1; h ═ B2-C2.

a3, finding the phase difference Δ θ between h and h', andand obtaining a corresponding initial frequency offset estimation value freq _ offset.

Further, the obtaining of the frequency offset estimation correction value after correcting the channel estimation values of the two time slots according to the inter-subcarrier interference matrix specifically includes;

b1, obtaining new h and h' by using a (γ) receive _ reference, wherein a (γ) is an inter-subcarrier interference matrix, γ is-freq _ offset/Δ f, γ is a frequency offset value, and Δ f is a frequency interval between subcarriers, and the calculation process of a (γ) is as follows:

w_-3＝exp(-jπ*(-3)/N)/(N*sin(π*(-3+γ)/N))*β；

w_-2＝exp(-jπ*(-2)/N)/(N*sin(π*(-2+γ)/N))*β；

w_-1＝exp(-jπ*(-1)/N)/(N*sin(π*(-1+γ)/N))*β；

w₀＝exp(-jπ*(0)/N)/(N*sin(π*(0+γ)/N))*β；

w₁＝exp(-jπ*(1)/N)/(N*sin(π*(1+γ)/N))*β；

w₂＝exp(-jπ*(2)/N)/(N*sin(π*(2+γ)/N))*β；

w₃＝exp(-jπ*(3)/N)/(N*sin(π*(3+γ)/N))*β；

where N is the number of sampling points determined by the bandwidth of the OFDMA system, β is a coefficient of the frequency offset, and it is assumed that the current subcarrier is k, w_-3Is the interference coefficient, w, of the k-3 th subcarrier_-2Is the interference coefficient, w, of the k-2 th subcarrier_-1Is the interference coefficient, w, of the k-1 th subcarrier₀Is the interference coefficient, w, of the current subcarrier₁Is the interference coefficient, w, of the k +1 th subcarrier₂Is the interference coefficient, w, of the k +2 th subcarrier₃Is the interference coefficient of the k +3 th subcarrier. Currently, one 12 subcarriers are taken to form a (γ), and an interference matrix a (γ) of the 12 subcarriers can be obtained.

b2, the above b1 of the present invention is different from the prior art in that a (γ) is introduced, and the new h and h 'calculated according to a (γ) receive _ reference are repeatedly used in the formulas for calculating h and h' of a2 and a3, so as to finally obtain a new freq _ offset (i.e., the new freq _ offset is the frequency offset estimation correction value finally obtained after the initial frequency offset estimation value is corrected).

Here, it should be noted that: after simulation proves that the repetition process is closer to the actual frequency offset value than the previous initial frequency offset estimation value freq _ offset after one time, and the effects of the repetition process for 1 time and multiple times are very close, so that the invention adopts one-time repetition and takes the new freq _ offset obtained by the last repetition as the final frequency offset estimation value.

The invention is illustrated below.

Example (b): take frequency offset estimation of LTE uplink system as an example.

In this embodiment, one subframe has two slots, 12 subcarriers are provided on one RB, the subcarrier spacing is Δ f 15000Hz, and the fixed frequency offset is set to 800 Hz. If the currently adopted system bandwidth is set to be 20MHz, the corresponding number of sampling points N is 2048, and a normal cyclic prefix (normalCP) in the OFDM system is adopted. The reference signal generated by the transmitting terminal is mapped into the resource grid according to the specified condition, and a single carrier frequency division multiple access (SC-FDMA) symbol is generated and transmitted. After passing through the channel, the receiving end receives the air interface data, extracts the reference signal of the transmitting end after passing through the channel, and accordingly performs the following frequency offset estimation, and performs frequency offset estimation correction through the A (gamma) introduced by the invention.

In this embodiment, the frequency offset estimation correction process, as shown in fig. 1, includes the following steps:

step 101, performing Least Square (LS, Least Square) channel estimation according to the received reference signal receive _ reference and local reference signal reference, selecting an RB, and obtaining channel estimation values h and h' of two time slots on the RB.

Step 102, calculating phase difference between h and h', and calculating initial frequency offset estimation value according to phase difference delta theta

Here, due to normal CP, one subframe has 14 symbols, two reference symbols are located at 3 and 10, respectively, and one subframe is 1ms long, so the time interval between two reference signals

The initial frequency deviation estimated value calculated by the methodfreq _ offset is 773 Hz.

And 103, calculating an inter-subcarrier interference matrix A (gamma) on the current RB according to the obtained frequency offset value gamma. Since most of inter-carrier interference (ICI) has a large influence between adjacent nearest sub-carriers, the influence is calculated by taking 3 sub-carriers around the sub-carrier at present. When N is 2048.

w_-3＝exp(-jπ*(-3)/2048)/(2048*sin(π*(-3+0.02)/2048))*β；

w_-2＝exp(-jπ*(-2)/2048)/(2048*sin(π*(-2+0.02)/2048))*β；

w_-1＝exp(-jπ*(-1)/2048)/(2048*sin(π*(-1+0.02)/2048))*β；

w₀＝exp(-jπ*(0)/2048)/(2048*sin(π*(0+0.02)/2048))*β；

w₁＝exp(-jπ*(1)/2048)/(2048*sin(π*(1+0.02)/2048))*β；

w₂＝exp(-jπ*(2)/2048)/(2048*sin(π*(2+0.02)/2048))*β；

w₃＝exp(-jπ*(3)/2048)/(2048*sin(π*(3+0.02)/2048))*β；

A = (\begin{matrix} w_{0} & w_{1} & w_{2} & w_{3} & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ w_{- 1} & w_{0} & w_{1} & w_{2} & w_{3} & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ w_{- 2} & w_{- 1} & w_{0} & w_{1} & w_{2} & w_{3} & 0 & 0 & 0 & 0 & 0 & 0 \\ w_{- 3} & w_{- 2} & w_{- 1} & w_{0} & w_{1} & w_{2} & w_{3} & 0 & 0 & 0 & 0 & 0 \\ 0 & w_{- 3} & w_{- 2} & w_{- 1} & w_{0} & w_{1} & w_{2} & w_{3} & 0 & 0 & 0 & 0 \\ 0 & 0 & w_{- 3} & w_{- 2} & w_{- 1} & w_{0} & w_{1} & w_{2} & w_{3} & 0 & 0 & 0 \\ 0 & 0 & 0 & w_{- 3} & w_{- 2} & w_{- 1} & w_{0} & w_{1} & w_{2} & w_{3} & 0 & 0 \\ 0 & 0 & 0 & 0 & w_{- 3} & w_{- 2} & w_{- 1} & w_{0} & w_{1} & w_{2} & w_{3} & 0 \\ 0 & 0 & 0 & 0 & 0 & w_{- 3} & w_{- 2} & w_{- 1} & w_{0} & w_{1} & w_{2} & w_{3} \\ 0 & 0 & 0 & 0 & 0 & 0 & w_{- 3} & w_{- 2} & w_{- 1} & w_{0} & w_{1} & w_{2} \\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & w_{- 3} & w_{- 2} & w_{- 1} & w_{0} & w_{1} \\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & w_{- 3} & w_{- 2} & w_{- 1} & w_{0} \end{matrix});

Step 104, when correcting the initial frequency offset estimation value freq _ offset, first obtaining new h and h' by using a (γ) receive _ reference, wherein a (γ) is an inter-subcarrier interference matrix, γ is-freq _ offset/Δ f, γ is a frequency offset value, and Δ f is a frequency interval between subcarriers; and then, repeatedly executing the

steps

102 and 103 to obtain new freq _ offset, wherein the freq _ offset is 795Hz, that is, the frequency offset estimation correction value finally obtained after the initial frequency offset estimation value is corrected is 795 Hz.

A system for correcting frequency offset estimation in an OFDMA system, the system comprising: a demodulation and initial frequency offset estimation unit and an initial frequency offset estimation correction unit. The demodulation and initial frequency offset estimation unit is used for OFDM demodulation at a receiving end after a reference signal generated by an OFDMA system transmitting end passes through a channel, and the receiving end extracts the received reference signal; estimating channel estimation values of two time slots according to a reference signal generated by a transmitting end and a reference signal received by a receiving end, and obtaining an initial frequency offset estimation value according to the channel estimation values of the two time slots. And the initial frequency offset estimation correction unit is used for correcting the initial frequency offset estimation value, and obtaining a frequency offset estimation correction value after correcting the channel estimation values of the two time slots according to the inter-subcarrier interference matrix.

The demodulation and initial frequency offset estimation unit is further configured to, in the case of calculating an initial frequency offset estimation value, obtain a phase difference according to channel estimation values of two slots, and calculate an initial frequency offset estimation value according to the phase difference.

Here, the initial frequency offset estimation correcting unit is further configured to, when the initial frequency offset estimation value is corrected in a case where the frequency offset estimation correction value is obtained by correcting the channel estimation values of the two time slots according to the inter-subcarrier interference matrix, calculate an inter-subcarrier interference matrix, obtain new channel estimation values of the two time slots according to the inter-subcarrier interference matrix and the reference signal received by the receiving end, obtain a phase difference according to the new channel estimation values of the two time slots, and calculate the frequency offset estimation correction value according to the phase difference.

Here, when the initial frequency offset estimation and correction unit is further configured to calculate the inter-subcarrier interference matrix, specifically, a (γ), the calculation formula adopted is as follows:

Here, the initial frequency offset estimation correction unit is further configured to calculate the w_-3W to_-2W to_-1W to₀W to₁W to₂And said w₃Respectively adopted calculation formulaThe method specifically comprises the following steps:

w_-3＝exp(-jπ*(-3)/N)/(N*sin(π*(-3+γ)/N))*β；

w_-2＝exp(-jπ*(-2)/N)/(N*sin(π*(-2+γ)/N))*β；

w_-1＝exp(-jπ*(-1)/N)/(N*sin(π*(-1+γ)/N))*β；

w₀＝exp(-jπ*(0)/N)/(N*sin(π*(0+γ)/N))*β；

w₁＝exp(-jπ*(1)/N)/(N*sin(π*(1+γ)/N))*β；

w₂＝exp(-jπ*(2)/N)/(N*sin(π*(2+γ)/N))*β；

w₃＝exp(-jπ*(3)/N)/(N*sin(π*(3+γ)/N))*β；

wherein,-freq _ offset/Δ f; the beta is a coefficient of frequency offset; the freq _ offset/delta f is an initial frequency offset estimation value, and delta f is a frequency interval between subcarriers; and N is the number of sampling points determined by the bandwidth of the OFDMA system.

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

Claims

1. A method for correcting frequency offset estimation of OFDMA system includes:

2. The method of claim 1, wherein obtaining initial frequency offset estimates based on the channel estimates for the two timeslots specifically comprises: and obtaining a phase difference according to the channel estimation values of the two time slots, and calculating an initial frequency offset estimation value according to the phase difference.

3. The method of claim 1, wherein the obtaining a frequency offset estimation correction value after correcting the channel estimation values of the two timeslots according to the inter-subcarrier interference matrix specifically comprises: when the initial frequency offset estimation value is corrected, calculating an inter-subcarrier interference matrix, obtaining new channel estimation values of two time slots according to the inter-subcarrier interference matrix and a reference signal received by the receiving end, obtaining a phase difference according to the new channel estimation values of the two time slots, and calculating a frequency offset estimation correction value according to the phase difference.

4. A method according to claim 2 or 3, characterized in that the inter-subcarrier interference matrix is specifically a (γ), and the calculation formula used is:

5. The method of claim 4, wherein w is_-3W to_-2W to_-1W to₀W to₁W to₂And said w₃The calculation formulas adopted respectively are specifically as follows:

w_-3＝exp(-jπ*(-3)/N)/(N*sin(π*(-3+γ)/N))*β；

w_-2＝exp(-jπ*(-2)/N)/(N*sin(π*(-2+γ)/N))*β；

w_-1＝exp(-jπ*(-1)/N)/(N*sin(π*(-1+γ)/N))*β；

w₀＝exp(-jπ*(0)/N)/(N*sin(π*(0+γ)/N))*β；

w₁＝exp(-jπ*(1)/N)/(N*sin(π*(1+γ)/N))*β；

w₂＝exp(-jπ*(2)/N)/(N*sin(π*(2+γ)/N))*β；

w₃＝exp(-jπ*(3)/N)/(N*sin(π*(3+γ)/N))*β；

wherein,

6. A system for correcting frequency offset estimation in an OFDMA system, the system comprising: a demodulation and initial frequency offset estimation unit and an initial frequency offset estimation correction unit; wherein,

7. The system of claim 6, wherein the demodulation and initial frequency offset estimation unit is further configured to, in the case of calculating the initial frequency offset estimation value, obtain a phase difference according to the channel estimation values of two slots, and calculate the initial frequency offset estimation value according to the phase difference.

8. The system according to claim 6, wherein said initial frequency offset estimation correction unit is further configured to, when correcting the initial frequency offset estimation value to obtain a frequency offset estimation correction value after correcting the channel estimation values of the two time slots according to the inter-subcarrier interference matrix, calculate an inter-subcarrier interference matrix, obtain new channel estimation values of the two time slots according to the inter-subcarrier interference matrix and a reference signal received by the receiving end, obtain a phase difference according to the new channel estimation values of the two time slots, and calculate the frequency offset estimation correction value according to the phase difference.

9. The system according to claim 7 or 8, wherein the initial frequency offset estimation correction unit is further configured to, when the inter-subcarrier interference matrix is specifically a (γ), use the following calculation formula:

10. The system of claim 9 wherein said initial frequency offset estimation correction unit is further configured to calculate said w_-3W to_-2W to_-1W to₀W to₁W to₂And said w₃In time, the calculation formulas adopted respectively are specifically as follows:

w_-3＝exp(-jπ*(-3)/N)/(N*sin(π*(-3+γ)/N))*β；

w_-2＝exp(-jπ*(-2)/N)/(N*sin(π*(-2+γ)/N))*β；

w_-1＝exp(-jπ*(-1)/N)/(N*sin(π*(-1+γ)/N))*β；

w₀＝exp(-jπ*(0)/N)/(N*sin(π*(0+γ)/N))*β；

w₁＝exp(-jπ*(1)/N)/(N*sin(π*(1+γ)/N))*β；

w₂＝exp(-jπ*(2)/N)/(N*sin(π*(2+γ)/N))*β；

w₃＝exp(-jπ*(3)/N)/(N*sin(π*(3+γ)/N))*β；

wherein,