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

Method and system for correcting frequency offset estimation in OFDM system Download PDF

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CN102130880A
CN102130880A CN2011100699120A CN201110069912A CN102130880A CN 102130880 A CN102130880 A CN 102130880A CN 2011100699120 A CN2011100699120 A CN 2011100699120A CN 201110069912 A CN201110069912 A CN 201110069912A CN 102130880 A CN102130880 A CN 102130880A
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frequency offset
interference
initial frequency
value
channel
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CN2011100699120A
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CN102130880B (en
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萧少宁
韩健
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中兴通讯股份有限公司
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/0001Arrangements for dividing the transmission path
    • H04L5/0003Two-dimensional division
    • H04L5/0005Time-frequency
    • H04L5/0007Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/0014Carrier regulation

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

一种OFDMA系统频偏估计的校正方法及系统 Method and system for correcting a frequency offset estimation in OFDMA systems

技术领域 FIELD

[0001] 本发明涉及频偏校正技术,尤其涉及一种正交频分多址接入(OFDMA,Orthogonal Frequency Division Multiple Access)系统频偏估计的校正方法及系统。 [0001] The present invention relates to frequency offset correction technique, particularly to a calibration method and an orthogonal frequency division multiple access system (OFDMA, Orthogonal Frequency Division Multiple Access) system, frequency offset estimation.

背景技术 Background technique

[0002] 在OFDMA系统中,由于存在晶振偏差和空间的多普勒频移的影响,会产生子载波的频率偏移,因此在接收端需要用参考信号进行频偏估计,然而现有技术仅根据参考信号进行的频偏估计方法并不准确,由于准确的频偏估计才能有效地校正由于频偏给信道估计带来的影响,因此,提高频偏估计的准确度是十分必要的。 [0002] In the OFDMA system, the deviation due to the crystal space and influence Doppler shift, the frequency offset is generated subcarrier, the receiver needs therefore frequency offset estimation reference signal, but the prior art only the frequency offset estimation method of a reference signal is not accurate, because accurate frequency offset estimation can effectively correct the frequency offset due to the effects of the channel estimation caused, therefore, to improve the accuracy of frequency offset estimation is necessary.

发明内容 SUMMARY

[0003] 有鉴于此,本发明的主要目的在于提供一种OFDMA系统频偏估计的校正方法及系统,能准确地估计出各种信道环境下的频偏估计值,从而提高了频偏估计的准确度。 [0003] In view of this, the main object of the present invention is to provide a method and system for correcting an OFDMA system estimates the frequency offset can accurately estimate the frequency offset estimation value in various channel environments, thereby improving the estimated frequency offset Accuracy.

[0004] 为达到上述目的,本发明的技术方案是这样实现的: [0004] To achieve the above object, the technical solution of the present invention is implemented as follows:

[0005] 一种OFDMA系统频偏估计的校正方法,该方法包括: [0005] An OFDMA system estimates the frequency offset correction method, the method comprising:

[0006] 正交频分多址接入(OFDMA)系统发射端产生的参考信号经过信道后在接收端进行正交频分(OFDM)解调,接收端提取出所接收的参考信号; [0006] The reference signal orthogonal frequency division multiple access (OFDMA) system produced by the transmitter after quadrature channel at the receiving end a frequency division (OFDM) demodulation, the receiver extracts the received reference signal;

[0007] 根据发射端产生的参考信号和接收端所接收的参考信号估计出两个时隙的信道估计值,根据所述两个时隙的信道估计值得到初始频偏估计值; [0007] The transmitter generates a reference signal and the reference signal received by the receiving end of the two slots of the estimated channel estimation value, estimated frequency offset estimation value to the initial worth based on the channel of the two time slots;

[0008] 对初始频偏估计值进行校正时,是根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值。 [0008] When the correction of the initial frequency offset estimation value, frequency offset estimation is obtained after the correction value is corrected based on the channel estimation value matrix of the interference between the two slots of the subcarrier.

[0009] 其中,根据所述两个时隙的信道估计值得到初始频偏估计值具体包括:根据两个时隙的信道估计值得到相位差,根据所述相位差计算出初始频偏估计值。 [0009] wherein, according to a channel of the two time slots worth to an estimated initial frequency offset estimation value comprises: estimating a channel according to a phase difference worth two time slots, calculated from the initial frequency offset estimation value of the retardation .

[0010] 其中,所述根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值具体包括:对初始频偏估计值校正时,计算出子载波间干扰矩阵,根据所述子载波间干扰矩阵和所述接收端所接收的参考信号得到新的两个时隙的信道估计值,根据新的两个时隙的信道估计值得到相位差,根据所述相位差计算出频偏估计校正值。 [0010] wherein, according to the channel estimation value matrix of the interference between the two slots of the sub-carriers to obtain a correction value to correct the frequency offset estimation comprises: a correction value of the initial frequency offset estimation, the calculated inter-subcarrier matrix interference, inter-subcarrier interference matrix and the reference signal received by the receiving end to obtain the channel estimation value according to two new slot, according to two new slot channel estimation phase difference worth, according to the said phase correction value to calculate the frequency offset estimation.

[0011] 其中,所述子载波间干扰矩阵具体为A(Y),所采用的计算公式为:[0012] [0011] wherein the ICI matrix specifically A (Y), the calculation formula is used: [0012]

Figure CN102130880AD00061

[0013] 其中,当前子载波的个数为k时,w_3为第k_3的子载波的干扰系数,I2为第k_2 的子载波的干扰系数,为第k-Ι的子载波的干扰系数,Wtl为当前的子载波的干扰系数,Wl 为第k+Ι的子载波的干扰系数,W2为第k+2的子载波的干扰系数,W3为第k+3的子载波的干扰系数,Y为频率偏移值。 [0013] wherein, when the current number of sub-carriers is k, w_3 subcarrier interference coefficients of k_3, I2 of the interference coefficient is k_2 of subcarriers, the subcarrier of a k-Ι interference coefficients, Wtl for the current interference coefficient subcarriers, Wl is the k + interference coefficient subcarriers Ι is, W2 interference coefficients of the sub-carriers of k + 2 is, W3 interference coefficients of the sub-carriers of k + 3 is, Y is frequency offset value.

[0014] 其中,所述w_3、所述w_2、所述、、所述Wtl、所述W1、所述W2和所述W3分别采用的计算公式具体为: [0014] wherein the formula w_3, the w_2, said ,, the Wtl, the W1, W2 and the said W3 respectively specifically:

[0015] w_3 = exp (-j 31 * (_3) /N) / (N*sin ( π * (-3+ γ ) /N)) * β [0015] w_3 = exp (-j 31 * (_3) / N) / (N * sin (π * (-3+ γ) / N)) * β

[0016] ι2 = exp (-j π * (_2) /N) / (N*sin ( π * (-2+ γ ) /N)) * β [0016] ι2 = exp (-j π * (_2) / N) / (N * sin (π * (-2+ γ) / N)) * β

[0017] W^1 = exp (-j π * (-1) /N) / (N*sin ( π * (-1+ y ) /N)) * β [0017] W ^ 1 = exp (-j π * (-1) / N) / (N * sin (π * (-1+ y) / N)) * β

[0018] w0 = exp (-j π * (0) /N) / (N*sin ( ji * (0+ y ) /N)) * β [0018] w0 = exp (-j π * (0) / N) / (N * sin (ji * (0+ y) / N)) * β

[0019] W1 = exp (-j π * (1) /N) / (N*sin (Ji * (1+ y ) /N)) * β [0019] W1 = exp (-j π * (1) / N) / (N * sin (Ji * (1+ y) / N)) * β

[0020] w2 = exp (-j π * (2) /N) / (N*sin ( π * (2+ y ) /N)) * β [0021 ] W3 = exp (-j π * (3) /N) / (N*sin (Ji * (3+ γ ) /N)) * β [0020] w2 = exp (-j π * (2) / N) / (N * sin (π * (2+ y) / N)) * β [0021] W3 = exp (-j π * (3) / N) / (N * sin (Ji * (3+ γ) / N)) * β

[0022] 其中, [0022] wherein,

Figure CN102130880AD00062

率偏移的系数;所述freq_0ffSet/ Δ f为初始频偏估计值,Δ f为子载波间的频率间隔;所述N为OFDMA系统带宽确定的采样点数,上述j为虚数单位,f = -1。 Rate offset coefficients; the freq_0ffSet / Δ f is the initial frequency offset estimation value, Δ f is the frequency interval between subcarriers; N is an OFDMA system the bandwidth determination of the sampling points, the above-described j is an imaginary unit, f = - 1.

[0023] 一种OFDMA系统频偏估计的校正系统,该系统包括:解调及初始频偏估计单元、初始频偏估计校正单元;其中, [0023] An OFDMA system frequency offset estimation correction system, the system comprising: a demodulator and initial frequency offset estimation unit estimating an initial frequency offset correction unit; wherein,

[0024] 所述解调及初始频偏估计单元,用于OFDMA系统发射端产生的参考信号经过信道后在接收端进行OFDM解调,接收端提取出所接收的参考信号;根据发射端产生的参考信号和接收端所接收的参考信号估计出两个时隙的信道估计值,根据所述两个时隙的信道估计值得到初始频偏估计值; [0024] The initial frequency offset estimation and demodulation unit, the transmitter for an OFDMA system generates a reference signal after OFDM demodulation channel at the receiving end, the receiving end to extract a received reference signal; generated according to the reference transmitter the reference signal and the reception signal terminal received two time slots estimated channel estimation value, estimated frequency offset estimation value to the initial worth based on the channel of the two time slots;

[0025] 所述初始频偏估计校正单元,用于对初始频偏估计值进行校正时,是根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值。 [0025] The estimation of the initial frequency offset correction unit for correcting the time of the initial frequency offset estimation value, frequency offset estimation is obtained is corrected according to the corrected channel estimation value matrix of the interference between the two slots subcarriers value.

[0026] 其中,所述解调及初始频偏估计单元,进一步用于在计算初始频偏估计值情况下, 根据两个时隙的信道估计值得到相位差,根据所述相位差计算出初始频偏估计值。 [0026] wherein the initial frequency offset estimation and demodulation means is further for calculating an initial frequency offset in the case where the estimation value, based on the channel estimation slots worth two phase difference is calculated based on the initial phase frequency offset estimate value. [0027] 其中,所述初始频偏估计校正单元,进一步用于根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值情况下,对初始频偏估计值校正时, 计算出子载波间干扰矩阵,根据所述子载波间干扰矩阵和所述接收端所接收的参考信号得到新的两个时隙的信道估计值,根据新的两个时隙的信道估计值得到相位差,根据所述相位差计算出频偏估计校正值。 [0027] wherein the initial frequency offset correction estimation unit for obtaining frequency offset estimation is further correction value is corrected in accordance with the situation after the channel estimation value matrix of the interference between the two slots of the subcarrier, the initial frequency offset when the estimated value correction, the calculated inter-subcarrier interference matrix, two new slot obtained according to the inter-subcarrier interference matrix and the reference signal received by the receiving end of the channel estimation value, according to two new slot worth to channel estimation phase, a phase difference is calculated based on the estimated frequency offset correction value.

[0028] 其中,所述初始频偏估计校正单元,进一步用于计算子载波间干扰矩阵具体为A(Y)时,所采用的计算公式为: [0028] wherein the initial frequency offset estimation correcting unit is further adapted to calculate the inter-subcarrier interference is particularly matrix A (Y), the calculation formula is used:

[0029] [0029]

Figure CN102130880AD00071

[0030] 其中,当前子载波的个数为k时,w_3为第k-3的子载波的干扰系数,I2为第k-2 的子载波的干扰系数,为第k-Ι的子载波的干扰系数,Wtl为当前的子载波的干扰系数,Wl 为第k+Ι的子载波的干扰系数,W2为第k+2的子载波的干扰系数,W3为第k+3的子载波的干扰系数,Y为频率偏移值。 [0030] wherein, when the current number of sub-carriers is k, w_3 subcarrier interference coefficients of k-3, I2 of the interference coefficients of sub-carriers k-2, the first subcarrier of the k-Ι interference coefficients, Wtl current subcarrier interference coefficients, Wl interference coefficients of the sub-carriers of k + Ι is, W2 interference coefficients of the sub-carriers of k + 2 is, W3 subcarrier of the k + 3 of the interference factor, Y is the frequency offset value.

[0031] 其中,所述初始频偏估计校正单元,进一步用于计算所述、所述w_2、所述、所述《0、所述W1、所述W2和所述W3时,分别采用的计算公式具体为 [0031] wherein the initial frequency offset estimation correcting unit is further for calculating the said w_2, said calculating the "0, the said W1 and W2 when the W3, respectively, and The formula is

[0032] w_3 = exp (_j π * (_3) /N) / (N*sin ( π * (—3+ Y ) /N)) * β [0032] w_3 = exp (_j π * (_3) / N) / (N * sin (π * (-3+ Y) / N)) * β

[0033] ι2 = exp (_j π * (_2) /N) / (N*sin ( π * (-2+ γ ) /N)) * β [0033] ι2 = exp (_j π * (_2) / N) / (N * sin (π * (-2+ γ) / N)) * β

[0034] W^1 = exp (-j π * (-1) /N) / (N*sin ( π * (-1+ y ) /N)) * β [0034] W ^ 1 = exp (-j π * (-1) / N) / (N * sin (π * (-1+ y) / N)) * β

[0035] w0 = exp (-j π * (0) /N) / (N*sin (Ji * (0+ γ ) /N)) * β [0035] w0 = exp (-j π * (0) / N) / (N * sin (Ji * (0+ γ) / N)) * β

[0036] W1 = exp (-j π * (1) /N) / (N*sin (Ji * (1+y )/N)) * β [0036] W1 = exp (-j π * (1) / N) / (N * sin (Ji * (1 + y) / N)) * β

[0037] w2 = exp (-j π * (2) /N) / (N*sin ( π * (2+ γ ) /N)) * β [0037] w2 = exp (-j π * (2) / N) / (N * sin (π * (2+ γ) / N)) * β

[0038] W3 = exp (-j π * (3) /N) / (N*sin (Ji * (3+ γ ) /N)) * β [0038] W3 = exp (-j π * (3) / N) / (N * sin (Ji * (3+ γ) / N)) * β

[0039] [0039]

Figure CN102130880AD00072

;所述β 为频 ; Β is the frequency

率偏移的系数;所述freq_0ffSet/ Δ f为初始频偏估计值,Δ f为子载波间的频率间隔;所述N为OFDMA系统带宽确定的采样点数,上述j为虚数单位,f = -1。 Rate offset coefficients; the freq_0ffSet / Δ f is the initial frequency offset estimation value, Δ f is the frequency interval between subcarriers; N is an OFDMA system the bandwidth determination of the sampling points, the above-described j is an imaginary unit, f = - 1. [0040] 本发明OFDMA系统发射端产生的参考信号经过信道后在接收端进行正交频分(OFDM)解调,接收端提取出所接收的参考信号;根据发射端产生的参考信号和接收端所接收的参考信号估计出两个时隙的信道估计值,根据所述两个时隙的信道估计值得到初始频偏估计值;对初始频偏估计值进行校正时,是根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值。 [0040] The reference signal OFDMA system according to the present invention, the transmitting end generated after channel orthogonal at the receiving end a frequency division (OFDM) demodulation, the receiver extracts the reference signal received; in accordance with the reference signal and the receiver transmitter generated by receiving the reference signal estimated channel estimation value of the two slots, the initial frequency offset estimation is worth based on the channel estimation value of the two time slots; when corrected initial frequency offset estimation value, based on inter-subcarrier interference matrix two slots of the channel estimate for frequency offset estimation obtained correction value after correction.

[0041] 采用本发明,通过引入子载波间干扰矩阵,并根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值,能准确地估计出各种信道环境下的频偏估计值,从而提高了频偏估计的准确度。 [0041] According to the present invention, by introducing inter-subcarrier interference matrix, and estimating the frequency offset correction value to obtain the corrected channel estimation value matrix of the interference between the two slots of subcarriers, it can accurately estimate the various frequency offset estimation value in a channel environment, thereby improving the accuracy of the estimated frequency offset.

附图说明 BRIEF DESCRIPTION

[0042] 图1为本发明实施例进行频偏校正的实现流程示意图。 [0042] Figure 1 is a schematic flow diagram of embodiment achieve frequency offset correction is performed invention. 具体实施方式 Detailed ways

[0043] 本发明的基本思想是:通过引入子载波间干扰矩阵,并根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值,能准确地估计出各种信道环境下的频偏估计值,从而提高了频偏估计的准确度。 [0043] The basic idea of ​​the invention is: through the introduction of ICI matrix, and estimating the frequency offset correction value to obtain the corrected channel estimation value matrix of the interference between the two slots of the subcarriers, accurate estimate a frequency offset estimate various channel environments, thereby improving the accuracy of the estimated frequency offset.

[0044] 下面结合附图对技术方案的实施作进一步的详细描述。 [0044] The following describes embodiments of the technical solutions described in further detail in conjunction.

[0045] 一种OFDMA系统频偏估计的校正方法,该方法主要包括以下内容: [0045] An OFDMA system estimates the frequency offset correction method, the method mainly includes the following contents:

[0046] OFDMA系统发射端产生的参考信号经过信道后在接收端进行OFDM解调,接收端提取出所接收的参考信号;根据发射端产生的参考信号和接收端所接收的参考信号估计出两个时隙的信道估计值,根据所述两个时隙的信道估计值得到初始频偏估计值;对初始频偏估计值进行校正时,是根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值。 Reference signal [0046] OFDMA system transmitter generated after the channel at the receiving end for OFDM demodulation, the receiver extracts the reference signal received; a reference signal transmitter generates a reference signal and the receiving end the received estimated two channel slot estimate the initial frequency offset estimation worth based on the channel estimation value of the two time slots; when corrected initial frequency offset estimation value, based on inter-subcarrier interference matrix of the two slots obtaining channel estimates estimated frequency offset correction value after correction. 该频偏估计校正值为对初始频偏估计值进行校正后最终得到的频偏估计校正值。 The frequency offset estimation of frequency offset correction value to correct the initial frequency offset estimation value estimated correction value is finally obtained.

[0047] 进一步的,所述根据发射端产生的参考信号和接收端所接收的参考信号估计出两个时隙的信道估计值,根据所述两个时隙的信道估计值得到初始频偏估计值具体包括: [0047] Further, according to the estimated reference signal generated by the transmitter and the receiver reference signal received by the channel estimation value of the two time slots worth initial frequency offset estimation according to the channel estimation of the two slots specific values ​​include:

[0048] al、OFDMA系统发射端产生的参考信号reference经过信道后在接收端进行OFDM 解调后提取参考信号receive_reference。 [0048] After the reference channel through the reference signal al, OFDMA transmitter system to extract the reference signal generated at the receiving end receive_reference for OFDM demodulation. 其中,针对reference而言,实际是在一个子帧发送了2个参考信号,也就是说reference的值有2个;针对receive_reference而言, 实际上是在一个子帧接收了2个参考信号,也就是说receive^eference的值有2个,与reference的值相区别。 Wherein, for the reference, the actual one subframe is transmitted in two reference signals, that is to say there are two reference values; for receive_reference, it is in fact receiving a subframe two reference signals, That receive ^ eference value has 2, distinguished from the reference value. 除此之外,接收端本地的信号还包括与reference的值相同的本地参考信号,也就是说,该本地参考信号也是2个,且与reference的值相同。 In addition, the receiving end further includes a local signal with a reference value of the same local reference signal, i.e., the local reference signal is 2, and the same with the reference values.

[0049] a2、选取一个合适的资源块(RB),采用现有的OFDM系统的信道估计方法,根据receive_reference和reference,估计出两个时隙的信道估计值,分别为h和h'。 [0049] a2, select an appropriate resource blocks (the RB), a conventional OFDM system using the channel estimation method, and in accordance with receive_reference reference, estimated channel estimation value of the two slots, respectively, h and h '. 其中, 针对h和h '的计算方法而言,如果2个reference的值分别为Al、A2 ;令2个receive_ reference的值分别为Bi、B2 ;令接收端与reference的值相同的本地参考信号,2个本地参考信号的值分别为Cl = Al、C2 = A2 ;则h = Bl-Cl ;h' = B2-C2。 The reference value of the same local reference signal so that the receiving end; wherein, for the purposes of calculation h and h ', and if the values ​​of the two reference were Al, A2; 2 Receive_ so reference values ​​are Bi, B2 , the value of the local reference signal 2 are Cl = Al, C2 = A2; the h = Bl-Cl; h '= B2-C2.

[0050] a3、求出h和h'之间的相位差Δ θ,并且由/r叫得到相应的初始频偏估计值freq_offseto [0050] a3, and h determine the phase difference h 'between Δ θ, and called by a / r to obtain the corresponding initial frequency offset estimation value freq_offseto

[0051] 进一步的,所述根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值具体包括;[0052] bl、用4(力*仪沈丨%_仪作仪11(^分别得到新的11和11',其中A(Y)是子载波间干扰矩阵,Y = -freq_offset/Af, y是频率偏移值,Δ f是子载波间的频率间隔,其中A(Y)的计算过程如下: [0051] Further, according to the channel estimation value matrix of the interference between the two slots of the sub-carrier frequency offset estimation is corrected to obtain a correction value comprises; [0052] bl, using 4 (Shen Shu instrument force * instrument as instrument 11% _ (^ new respectively 11 and 11 ', where a (Y) is the ICI matrix, Y = -freq_offset / Af, y is the frequency offset value, Δ f is between subcarriers frequency interval, where a (Y) is calculated as follows:

[0053] [0053]

Figure CN102130880AD00091
Figure CN102130880AD00092

[0062] 其中,N是OFDMA系统带宽确定的采样点数,β是频率偏移的一个系数,假设当前子载波是k,w_3是第k-3的子载波的干扰系数,I2是第k-2的子载波的干扰系数,I1是第k-Ι的子载波的干扰系数,W0是当前的子载波的干扰系数,W1是第k+Ι的子载波的干扰系数,W2是第k+2的子载波的干扰系数,W3是第k+3的子载波的干扰系数。 [0062] where, N is an OFDMA system bandwidth determined number of samples, a coefficient beta] is the frequency offset is assumed that the current subcarrier k, w_3 is the interference coefficient on subcarrier k-3, I2 of the first k-2 the interference coefficients subcarriers, I1 is the interference coefficient subcarriers of the k-Ι is, W0 is the interference coefficient current subcarriers, W1 is the interference coefficient subcarriers of k + Ι of, W2 are k + 2 is subcarrier interference coefficients, W3 is the interference coefficient on subcarrier k + 3 in. 当前取一个12个子载波形成一个A ( γ ),可以得到12个子载波的干扰矩阵A ( γ )。 Taking a current sub-carriers forming a 12 A (γ), can be obtained interference matrix A (γ) 12 subcarriers.

[0063] b2、将本发明上述b 1中,区别于现有技术通过弓丨入A ( γ ),并根据A ( γ ) *receive_ reference计算得到的新的h和h',重复采用上述a2、a3计算h和h '的公式,最终得到新的frecLoffset (新的freq_0fTSet即为对初始频偏估计值进行校正后最终得到的频偏估计校正值)。 [0063] b2, the above-described present invention, b 1, distinguished from the prior art A (γ) by Shu bow, and in accordance with A (γ) * receive_ reference calculated new h and h ', the above-described repeating a2 , a3 calculation formula h and h ', the finally obtained new frecLoffset (after freq_0fTSet is the new initial frequency offset estimation value for correcting frequency offset estimation finally obtained correction value).

[0064] 这里需要指出的是:经过仿真证明此重复过程经过一次之后,较之前的初始频偏估计值freq_offSet更加接近实际的频偏值,而且这种重复过程1次和多次的效果是非常接近的,所以本发明采用一次重复,并把最后经过一次重复得到的上述新的freq_0ffSet 作为最终的频偏估计值。 [0064] It should be noted that: The simulation proved that this iterative process through once, compared to the previous initial frequency offset estimation value freq_offSet closer to the actual frequency offset value, and this process is repeated several times and once the effect is very close, the present invention uses repeated once, and after the last iteration of said new freq_0ffSet obtained as the final frequency offset estimated value.

[0065] 以下对本发明进行举例阐述。 [0065] The present invention will be cited as an example.

[0066] 实施例:以LTE上行链路系统的频偏估计为例。 [0066] Example: In an LTE uplink frequency offset estimation system as an example. [0067] 本实施例中,一个子帧有两个时隙,一个RB上有12个子载波,子载波间隔是Af =15000Hz,固定频偏设置为800Hz。 [0067] In this embodiment, one subframe has two slots, one on the RB has 12 subcarriers, the subcarrier spacing is Af = 15000Hz, fixed frequency offset is set to 800Hz. 如果设置当前采用的系统带宽是20MHz,对应的采样点数N= 2048,采用正常的OFDM系统中循环前缀(norma 1 CP)。 If the system bandwidth is currently used 20MHz, corresponding to the number of samples N = 2048, a normal OFDM system uses a cyclic prefix (norma 1 CP). 发射端生成的参考信号根据规定条件映射到资源网格中,并生成单载波频分多址(SC-FDMA)符号发射出去。 Generating a reference signal transmitter mapping the resource grid in accordance with a predetermined condition and generate single-carrier frequency division multiple access (SC-FDMA) symbols emitted. 经过信道后,接收端接收到空口数据,并提取出发射端经过信道后的参考信号,并据此进行以下频偏估计,且通过本发明引入的A(Y)进行频偏估计校正。 After the channel, the data receiving end receives the air interface, and extracts a reference signal transmitter via the channel, and accordingly the frequency offset estimation, and A (Y) is introduced by the present invention for correcting frequency offset estimation.

[0068] 其中,本实施例进行频偏估计校正流程,如图1所示,包括以下步骤: [0068] where, the estimated frequency offset according to the present embodiment, the correction process, shown in Figure 1, comprising the steps of:

[0069] 步骤101、根据接收得到的参考信号receivejeference与本地参考信号reference进行最小二乘(LS,Least Square)信道估计,选出一个RB,得到这个RB上两个时隙的信道估计值h和h'。 [0069] Step 101, the least square (LS, Least Square) channel estimation, selects a reference signal RB receivejeference received local reference signal obtained by reference, to give two RB on the slots and the channel estimation value h h '.

[0070] 步骤102、计算h和h'的相位差,并且由相位差Δ θ计算出初始频偏估计值 [0070] Step 102 calculates h and h 'of the phase difference, and the phase difference Δ θ is calculated by the initial frequency offset estimation value

Figure CN102130880AD00101

在这里由于是normal CP,因此,一个子帧有14个符号,两个参考InAt Because here it is the normal CP, and therefore, one subframe has 14 symbols, two reference InAt

符号的位置分别为3和10,一个子帧时长为1ms,所以两个参考信号之间的时间间隔Af=(10^)Xl = 0.5ms ,由此计算出的初始频偏估计值freq_offset为773Hz。 Symbol positions 3 and 10, respectively, when a sub-frame length is 1ms, the time interval between the two reference signals Af = (10 ^) Xl = 0.5ms, thus calculated initial frequency offset estimation value of 773Hz freq_offset .

[0071] 步骤103、根据得到的频率偏移值γ,计算当前RB上的子载波间干扰矩阵Α( γ )。 [0071] Step 103. The frequency offset value obtained gamma], calculated on the current inter-carrier interference matrix RB Α (γ). 由于大多数的载波间干扰(ICI)是相邻最近的几个子载波间影响较大,所以当前取子载波附近左右各3个子载波计算它们的影响。 Since most of the inter-carrier interference (ICI) between adjacent sub-carriers in several recent influence is large, the current taken near the left and right of each sub-carrier 3 subcarriers to calculate their impact. 此时N = 2048。 In this case N = 2048.

[0072] β ( (2048 -] =sin (冗* 0.02) * exp ϊπ * 0.02 * - V ^ ^ ( 2048 [0073] W-3 =exp (- j 31 * (-3) /2048) / (2048*sin ( π *(-3+0.02), /2048))*β[0074] I2 =exp (- jπ *(-2)/2048)/(2048*sin( π *(-2+0.02), /2048))*β[0075] WI =exp (- jπ *(-1)/2048)/(2048*sin( π *(-1+0.02), /2048))*β[0076] W0 =exp(-j π * (0)/2048) A2048*sin ( π *(0+0. 02)/2048))* β ; [0077] W1 =exp(-j 3i*(l)/2048)/(2048*sin(3i *(l+0. 02)/2048))* β ; [0078] W2 =exp(-j π * (2)/2048) A2048*sin ( π *(2+0. 02)/2048))* β ; [0079] W3 =exp(-j π * (3)/2048) A2048*sin ( π *(3+0. 02)/2048))* β ;[0080] [0072] β ((2048 -] = sin (redundant * 0.02) * exp ϊπ * 0.02 * - V ^ ^ (2048 [0073] W-3 = exp (- j 31 * (-3) / 2048) / ( 2048 * sin (π * (- 3 + 0.02), / 2048)) * β [0074] I2 = exp (- jπ * (- 2) / 2048) / (2048 * sin (π * (- 2 + 0.02) , / 2048)) * β [0075] WI = exp (- jπ * (- 1) / 2048) / (2048 * sin (π * (- 1 + 0.02), / 2048)) * β [0076] W0 = exp (-j π * (0) / 2048) A2048 * sin (π * (0 + 0 02) / 2048.)) * β; [0077] W1 = exp (-j 3i * (l) / 2048) / (. 2048 * sin (3i * (l + 0 02) / 2048)) * β; [0078] W2 = exp (-j π * (2) / 2048) A2048 * sin (π * (2 + 0 02. ) / 2048)) * β; [0079] W3 = exp (-j π * (3) / 2048) A2048 * sin (π * (3 + 0 02) / 2048)) * β;. [0080]

Figure CN102130880AD00111

[0081 ] 步骤104、对初始频偏估计值freq_offset进行校正时,先用A ( γ ) *receive_ reference分别得到新的h和h',其中A( γ )是子载波间干扰矩阵,、=-freq_offset/ Af, Y是频率偏移值,Af是子载波间的频率间隔;再将得到的新的h和h',重复执行步骤102、步骤103以得到新的freq_offset,此时freq_offset为795Hz,即对初始频偏估计值进行校正后最终得到的频偏估计校正值为795Hz。 [0081] Step 104, when the correction of the initial frequency offset estimation value freq_offset, first with A (γ) * receive_ reference respectively new h and h ', where A (γ) is the ICI matrix ,, = - freq_offset / Af, Y is a frequency offset value, of Af is the frequency interval between subcarriers; h then obtained and new h ', step 102 is repeatedly performed, step 103 to obtain new freq_offset, freq_offset case of 795 Hz, That is, after correcting the initial frequency offset estimation value finally obtained estimated frequency offset correction value 795Hz.

[0082] 一种OFDMA系统频偏估计的校正系统,该系统包括:解调及初始频偏估计单元、初始频偏估计校正单元。 [0082] An OFDMA system frequency offset estimation correction system, the system comprising: a demodulator and initial frequency offset estimation unit estimating an initial frequency offset correcting unit. 其中,解调及初始频偏估计单元用于OFDMA系统发射端产生的参考信号经过信道后在接收端进行OFDM解调,接收端提取出所接收的参考信号;根据发射端产生的参考信号和接收端所接收的参考信号估计出两个时隙的信道估计值,根据所述两个时隙的信道估计值得到初始频偏估计值。 Wherein the initial frequency offset estimation unit and a demodulation reference signal for generating an OFDMA system the transmitter channel after OFDM demodulation is performed at the receiving end, the receiving end to extract a received reference signal; and the receiver reference signal generated based on the transmitting end a received reference signal estimated channel estimation value of the two slots, the initial frequency offset estimation is worth based on the channel estimation value of the two slots. 初始频偏估计校正单元用于对初始频偏估计值进行校正时,是根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值。 Estimating an initial frequency offset correcting unit for correcting the time of the initial frequency offset estimation value, frequency offset estimation is obtained after the correction value is corrected based on the channel estimation value matrix of the interference between the two slots of the subcarrier.

[0083] 这里,解调及初始频偏估计单元进一步用于在计算初始频偏估计值情况下,根据两个时隙的信道估计值得到相位差,根据所述相位差计算出初始频偏估计值。 [0083] Here, the initial frequency offset estimation and demodulation unit is further configured to calculate the initial frequency offset estimation value, based on the channel estimation slots worth two phase difference calculated initial frequency offset estimation according to the phase difference value.

[0084] 这里,初始频偏估计校正单元进一步用于根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值情况下,对初始频偏估计值校正时,计算出子载波间干扰矩阵,根据所述子载波间干扰矩阵和所述接收端所接收的参考信号得到新的两个时隙的信道估计值,根据新的两个时隙的信道估计值得到相位差,根据所述相位差计算出频偏估计校正值。 [0084] Here, the initial frequency offset estimation correcting unit for obtaining frequency offset estimation is further correction value is corrected in accordance with the situation after the channel estimation value matrix of the interference between the two slots of the subcarrier, the initial frequency offset estimation value correction when the calculated inter-subcarrier interference matrix, to obtain two new slots according to the inter-subcarrier interference matrix and the reference signal received by the receiving end of the channel estimation value, according to two new slot channel estimation It is worth to the phase difference, the phase difference is calculated based on the estimated frequency offset correction value.

[0085] 这里,初始频偏估计校正单元进一步用于计算子载波间干扰矩阵具体为A(Y) 时,所采用的计算公式为:[0086] When [0085] Here, the initial frequency offset estimation correcting unit is further configured to calculate the inter-subcarrier interference is particularly matrix A (Y), the calculation formula is used: [0086]

Figure CN102130880AD00121

[0087] 其中,当前子载波的个数为k时,w_3为第k_3的子载波的干扰系数,I2为第k_2 的子载波的干扰系数,为第k-Ι的子载波的干扰系数,Wtl为当前的子载波的干扰系数,Wl 为第k+Ι的子载波的干扰系数,W2为第k+2的子载波的干扰系数,W3为第k+3的子载波的干扰系数,Y为频率偏移值。 [0087] wherein, when the current number of sub-carriers is k, w_3 subcarrier interference coefficients of k_3, I2 of the interference coefficient is k_2 of subcarriers, the subcarrier of a k-Ι interference coefficients, Wtl for the current interference coefficient subcarriers, Wl is the k + interference coefficient subcarriers Ι is, W2 interference coefficients of the sub-carriers of k + 2 is, W3 interference coefficients of the sub-carriers of k + 3 is, Y is frequency offset value.

[0088] 这里,初始频偏估计校正单元进一步用于计算所述w_3、所述w_2、所述、所述w0、 所述W1、所述W2和所述W3时,分别采用的计算公式具体为: [0088] Here, the initial frequency offset estimation unit is further configured to calculate a correction w_3, the w_2, the said W0, the W1, W2 and the W3 is the calculation formula were used for the specific :

[0089] w_3 = exp (_j π * (_3) /N) / (N*sin ( π * (—3+ Y ) /N)) * β [0089] w_3 = exp (_j π * (_3) / N) / (N * sin (π * (-3+ Y) / N)) * β

[0090] ι2 = exp (-j π * (_2) /N) / (N*sin ( π * (-2+ γ ) /N)) * β [0090] ι2 = exp (-j π * (_2) / N) / (N * sin (π * (-2+ γ) / N)) * β

[0091] W^1 = exp (-j π * (-1) /N) / (N*sin ( π * (-1+ Y ) /N)) * β [0091] W ^ 1 = exp (-j π * (-1) / N) / (N * sin (π * (-1+ Y) / N)) * β

[0092] w0 = exp (-j π * (0) /N) / (N*sin (Ji * (0+ γ ) /N)) * β [0092] w0 = exp (-j π * (0) / N) / (N * sin (Ji * (0+ γ) / N)) * β

[0093] W1 = exp (-j π * (1) /N) / (N*sin (Ji * (1+y )/N)) * β [0093] W1 = exp (-j π * (1) / N) / (N * sin (Ji * (1 + y) / N)) * β

[0094] w2 = exp (一j π * (2) /N) / (N*sin ( π * (2+ γ ) /N)) * β [0094] w2 = exp (a j π * (2) / N) / (N * sin (π * (2+ γ) / N)) * β

[0095] W3 = exp (-j π * (3) /N) / (N*sin (Ji * (3+ γ ) /N)) * β [0095] W3 = exp (-j π * (3) / N) / (N * sin (Ji * (3+ γ) / N)) * β

[0096] 其中, [0096] wherein,

Figure CN102130880AD00122

;所述β 为频 ; Β is the frequency

率偏移的系数;所述freq_0ffSet/ Δ f为初始频偏估计值,Δ f为子载波间的频率间隔;所述N为OFDMA系统带宽确定的采样点数。 Rate offset coefficients; the freq_0ffSet / Δ f is the initial frequency offset estimation value, Δ f is the frequency interval between subcarriers; N the number of sampling points is determined OFDMA system bandwidth.

[0097] 以上所述,仅为本发明的较佳实施例而已,并非用于限定本发明的保护范围。 [0097] The above descriptions are merely preferred embodiments of the present invention but are not intended to limit the scope of the present invention.

Claims (10)

1. 一种OFDMA系统频偏估计的校正方法,其特征在于,该方法包括:正交频分多址接入(OFDMA)系统发射端产生的参考信号经过信道后在接收端进行正交频分(OFDM)解调,接收端提取出所接收的参考信号;根据发射端产生的参考信号和接收端所接收的参考信号估计出两个时隙的信道估计值,根据所述两个时隙的信道估计值得到初始频偏估计值;对初始频偏估计值进行校正时,是根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值。 An OFDMA system estimates the frequency offset correction method, characterized in that, the method comprising: an orthogonal frequency division multiple access (OFDMA) system generates the reference signal transmitted after the end of the channel at the receiving end of an orthogonal frequency division (OFDM) demodulation, the receiver extracts a received reference signal; a channel estimation value estimated two slots according to the reference signal generated by the reference signal transmitting end and the receiving end the received channel according to the two slots It estimates the initial frequency offset estimation value worth; when corrected for the initial frequency offset estimation value, frequency offset estimation is obtained after the correction value is corrected on the basis of the interference matrix of the channel estimation slots between two subcarriers.
2.根据权利要求1所述的方法,其特征在于,根据所述两个时隙的信道估计值得到初始频偏估计值具体包括:根据两个时隙的信道估计值得到相位差,根据所述相位差计算出初始频偏估计值。 2. The method according to claim 1, wherein the initial frequency offset is estimated to be worth an estimated value comprises two slots of the channel according to: estimate a phase difference based on channel worth two slots, according to the said phase difference calculated initial frequency offset estimation value.
3.根据权利要求1所述的方法,其特征在于,所述根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值具体包括:对初始频偏估计值校正时, 计算出子载波间干扰矩阵,根据所述子载波间干扰矩阵和所述接收端所接收的参考信号得到新的两个时隙的信道估计值,根据新的两个时隙的信道估计值得到相位差,根据所述相位差计算出频偏估计校正值。 3. The method according to claim 1, wherein said disturbance estimation values ​​according to a channel matrix between the two slots subcarrier obtained after correcting the frequency offset estimation correction value comprises: an initial frequency offset when the estimated value correction, the calculated inter-subcarrier interference matrix, two new slot obtained according to the inter-subcarrier interference matrix and the reference signal received by the receiving end of the channel estimation value, according to two new slot worth to channel estimation phase, a phase difference is calculated based on the estimated frequency offset correction value.
4.根据权利要求2或3所述的方法,其特征在于,所述子载波间干扰矩阵具体为A( Y),所采用的计算公式为:A(r)W0 W1 W2 W3 0 0 0 0 0 0 0 0W_, W0 W1 W2 W3 0 0 0 0 0 0 0W_2 W_, W0 W1 W2 W3 0 0 0 0 0 0W_3 W_2 W_, W0 W1 W2 W3 0 0 0 0 00 W_3 W_2 W_, W0 W1 W2 W3 0 0 0 00 0 W_3 W_2 W_, W0 W1 W2 W3 0 0 00 0 0 w_3 W_2 W_, W0 W1 W2 W3 0 00 0 0 0 W_3 W_2 W_, W0 W1 W2 W3 00 0 0 0 0 W_3 W_2 W_, W0 W1 W2 W30 0 0 0 0 0 W_3 W_2 W_, W0 W1 W20 0 0 0 0 0 0 W_3 W_2 W_, W0 W10 0 0 0 0 0 0 0 W_3 W_2 W_, W0子载波的个 数为k时, w_3为第k-3的子载波的干扰系数 :,I2 为第载波的干扰系数,I1为第kl的子载波的干扰系数,Wtl为当前的子载波的干扰系数,Wl为第k+Ι的子载波的干扰系数,w2为第k+2的子载波的干扰系数,w3为第k+3的子载波的干扰系数,γ为频率偏移值。 4. The method of claim 2 or claim 3, wherein the inter-subcarrier interference is particularly matrix A (Y), the calculation formula used is: A (r) W0 W1 W2 W3 0 0 0 0 0 0 0 0W_, W0 W1 W2 W3 0 0 0 0 0 0 0W_2 W_, W0 W1 W2 W3 0 0 0 0 0 0W_3 W_2 W_, W0 W1 W2 W3 0 0 0 0 00 W_3 W_2 W_, W0 W1 W2 W3 0 0 0 00 0 w_3 W_2 W_, W0 W1 W2 W3 0 0 00 0 0 w_3 W_2 W_, W0 W1 W2 W3 0 00 0 0 0 w_3 W_2 W_, W0 W1 W2 W3 00 0 0 0 0 w_3 W_2 W_, W0 W1 W2 W30 when 0 0 0 0 0 w_3 W_2 W_, W0 W1 W20 0 0 0 0 0 0 w_3 W_2 W_, W0 W10 0 0 0 0 0 0 0 w_3 W_2 W_, the number of sub-carriers is W0 k, w_3 for the first k- interference coefficient subcarriers 3:, I2 of the interference coefficient carrier, I1 is the interference coefficient subcarriers of kl is, Wtl interference coefficients of the current sub-carriers, Wl subcarrier of the k + Ι the interference coefficient , w2 subcarrier k + 2 of the interference coefficients, w3 is the interference coefficient of the subcarriers k + 3 are, γ is the frequency offset value.
5.根据权利要求4所述的方法,其特征在于,所述、所述I2、所述、所述Wtl、所述W1、所述W2和所述W3分别采用的计算公式具体为:w_3 = exp (-j π * (-3) /N) / (N*sin ( π * (-3+ γ ) /N)) * β w_2 = exp (-j π * (-2) /N) / (N*sin ( π * (-2+ γ ) /N)) * β W^1 = exp (-j π * (-1) /N) / (N*sin ( π * (-1+ γ ) /N)) * β The method according to claim 4, wherein the calculating of the formula I2, the said Wtl, the W1, W2 and the said W3 respectively is specifically: w_3 = exp (-j π * (-3) / N) / (N * sin (π * (-3+ γ) / N)) * β w_2 = exp (-j π * (-2) / N) / ( N * sin (π * (-2+ γ) / N)) * β W ^ 1 = exp (-j π * (-1) / N) / (N * sin (π * (-1+ γ) / N)) * β
Figure CN102130880AC00031
Y = -freq_0ffset/ Δ f ;所述β 为频率偏移的系数;所述freq_0ffSet/Af为初始频偏估计值,Af为子载波间的频率间隔;所述N 为OFDMA系统带宽确定的采样点数,上述j为虚数单位,f = -1。 Y = -freq_0ffset / Δ f; said coefficient β is a frequency offset; the freq_0ffSet / Af initial frequency offset estimation value, Af is the frequency interval between subcarriers; N the number of sampling points of the OFDMA system bandwidth determination said j is an imaginary unit, f = -1.
6. 一种OFDMA系统频偏估计的校正系统,其特征在于,该系统包括:解调及初始频偏估计单元、初始频偏估计校正单元;其中,所述解调及初始频偏估计单元,用于OFDMA系统发射端产生的参考信号经过信道后在接收端进行OFDM解调,接收端提取出所接收的参考信号;根据发射端产生的参考信号和接收端所接收的参考信号估计出两个时隙的信道估计值,根据所述两个时隙的信道估计值得到初始频偏估计值;所述初始频偏估计校正单元,用于对初始频偏估计值进行校正时,是根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值。 An OFDMA system estimates the frequency offset correction system, wherein the system comprises: an initial frequency offset estimation and demodulation unit, an initial frequency offset estimation correcting unit; wherein the initial frequency offset estimation and demodulation unit, a reference signal transmitter for an OFDMA system generated after channel OFDM demodulation at the receiving end, the receiving end to extract a received reference signal; when two reference signals generated by reference signal transmitting end and a receiving end in accordance with the estimated received channel estimation value of the gap, according to a channel of the two time slots worth to estimate initial frequency offset estimation value; estimation of the initial frequency offset correction unit for correcting the time of the initial frequency offset estimation value is the inter-carrier according to the interference matrix of the channel estimation to obtain two time slots estimated frequency offset correction value after correction.
7.根据权利要求6所述的系统,其特征在于,所述解调及初始频偏估计单元,进一步用于在计算初始频偏估计值情况下,根据两个时隙的信道估计值得到相位差,根据所述相位差计算出初始频偏估计值。 7. The system according to claim 6, wherein said initial frequency offset estimation and demodulation means is further for calculating at an initial frequency offset estimation value, the phase is estimated based on channel worth two slots difference, a phase difference is calculated based on the initial frequency offset estimation value.
8.根据权利要求6所述的系统,其特征在于,所述初始频偏估计校正单元,进一步用于根据子载波间干扰矩阵对所述两个时隙的信道估计值进行校正后获得频偏估计校正值情况下,对初始频偏估计值校正时,计算出子载波间干扰矩阵,根据所述子载波间干扰矩阵和所述接收端所接收的参考信号得到新的两个时隙的信道估计值,根据新的两个时隙的信道估计值得到相位差,根据所述相位差计算出频偏估计校正值。 8. The system according to claim 6, wherein said initial frequency offset correction estimation unit for obtaining frequency offset is further corrected according to the channel estimation value matrix of the interference between the two slots subcarriers estimation correction value, the estimation of the initial frequency offset correction value calculated inter-subcarrier interference matrix, to obtain two new slots according to the inter-subcarrier interference matrix and the reference signal received by the receiving end of the channel estimate, phase estimate according to the channel worth two new slots, the phase difference is calculated based on the estimated frequency offset correction value.
9.根据权利要求7或8所述的系统,其特征在于,所述初始频偏估计校正单元,进一步用于计算子载波间干扰矩阵具体为A(Y)时,所采用的计算公式为: f 9. The system according to claim 78, wherein said initial frequency offset estimation correcting unit, when the calculated inter-subcarrier interference is particularly matrix A (Y) is further used, the calculation formula is used: f
Figure CN102130880AC00032
载波的干扰系数,为第k-Ι的子载波的干扰系数,Wtl为当前的子载波的干扰系数,W1为第k+Ι的子载波的干扰系数,w2为第k+2的子载波的干扰系数,w3为第k+3的子载波的干扰系数,Y为频率偏移值。 Interference coefficients carrier, subcarrier of the k-Ι the interference coefficients, Wtl current subcarrier interference coefficients, W1 of interference coefficients of the sub-carriers of k + Ι is, w2 subcarrier of the k + 2 is interference coefficients, w3 is the interference coefficient subcarriers k + 3 of the first, Y is the frequency offset value.
10.根据权利要求9所述的系统,其特征在于,所述初始频偏估计校正单元,进一步用于计算所述I3、所述I2、所述I1、所述《0、所述W1、所述W2和所述W3时,分别采用的计算公式具体为: 10. The system according to claim 9, wherein said initial frequency offset estimation correcting unit is further for calculating the I3, the I2, the I1, the "0, the W1, the when the said W2 and W3, respectively calculated specifically:
Figure CN102130880AC00041
其中,々= sin(;r*7)*exp ; γ =-freq_offset/Δ f ;所述β 为频率偏移的系数;所述freq_0ffSet/Af为初始频偏估计值,Af为子载波间的频率间隔;所述N 为OFDMA系统带宽确定的采样点数,上述j为虚数单位,f = -1。 Wherein 々 = sin (; r * 7) * exp; γ = -freq_offset / Δ f; said coefficient β is a frequency offset; the freq_0ffSet / Af initial frequency offset estimation value, of Af between subcarriers frequency interval; N is an OFDMA system the bandwidth determination of the sampling points, the above-described j is an imaginary unit, f = -1.
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