CN103581078B - A kind of IQ imbalance compensation method based on Golay complementary series - Google Patents

Abstract

The invention belongs to wireless communication technology field, be specifically related to the method by the one IQ imbalance compensation based on Gray (Golay) complementary series in the wireless communication system of inphase quadrature (IQ, In phase Quadrature) two-way imbalance interference.By structure training sequence to and send；Receiving terminal receives the training sequence pair described in S1, and the sequence received is circulated relevant treatment respectively；Compensate steps such as receiving the signal unbalanced impact of IQ, under conditions of requiring no knowledge about channel information, estimate the unbalanced multiple parameter of IQ, and then it is uneven to compensate IQ.

Description

A kind of IQ imbalance compensation method based on Golay complementary series

Technical field

The invention belongs to wireless communication technology field, be specifically related to by inphase quadrature (IQ, In-phase Quadrature) The side of the one IQ imbalance compensation based on Gray (Golay) complementary series in the wireless communication system of two-way imbalance interference Method.

Background technology

OFDM (OFDM, Orthogonal Frequency Division Multiplexing) technology due to Its parallel transmission, makes signal bandwidth be less than the coherence bandwidth of channel and be effective against multipath, and receiving terminal complexity of equalization is relatively low Advantage is accepted extensively by broadband connections.Single carrier frequency domain equalization (SC-FDE, Single Carrier Modulation with Frequency Domain Equalization) as OFDM, make received by the reception data of frequency-selective channel The complexity of equalization of end is substantially reduced, and is one of technology being effective against multi-path jamming.Compared with OFDM, it has the equal merit of ebb The advantages such as rate ratio (PAPR, Peak to Average Power Ratio).Therefore, OFDM and SC-FDE becomes a lot of channel radio The technology of letter standard access network, such as global standards Long Term Evolution (LTE, Long Time Evolution) up-link sampling SC- FDE, downlink uses OFDM；The standards such as IEEE 802.15, IEEE 802.16 all contain OFDM and SC-FDE and modulate body System.

Radio communication needs carrier modulation, after AFE (analog front end) (FE, Front-End) is modulated or before demodulation (or both Have) inphase quadrature (IQ, In-phase Quadrature) two paths of signals imbalance systematic function will be caused to decline, especially It is to use the Direct Conversion structure of low cost or the higher system such as millimeter-wave communication system of carrier frequency.IQ imbalance refers to I Not mating of amplitude between branch and Q branch and phase place, both may reside in transmitter and can also be present in receiver.

In general, IQ imbalance can be divided into frequency unrelated (FI, Frequency Independent) and frequency dependence The IQ of (FD, Frequency Dependent) is uneven.The IQ imbalance of FI is by local oscillator (LO, Local Oscillator) cause.The IQ imbalance of FD also includes being turned by other analog devices, such as analog filter, amplifier, digital-to-analogue Parallel operation (DAC, Digital-to-Analog Converter) or analog-digital converter (ADC, Analog-to-Digital Converter) impact caused.

More existing IQ imbalance compensation schemes, are roughly divided into two kinds: be respectively independent of or rely on IQ injustice The compensation method of weighing apparatus parameter estimation.Such as, with the benefit based on Interference Cancellation (IC, Interference Cancellation) Repay with blind source separating (BSS, Blind Source Separation) based on compensation, it is not necessary to any training sequence, the most not Needing to estimate IQ imbalance parameter, its method describes and is referred to document: M.Valkama, M.Renfors, and V.Koivunen.Blind signal estimation in conjugate signal models with Application to I/Q imbalance compensation [J] .IEEE Signal Process, 2005,12 (11): 733 736. and M.Valkama, M.Renfors, V.Koivunen.Advanced method for I/Q imbalance compensation in communication receivers[J].IEEE Transaction on Signal Processing, 2001,49 (10): 2335-2344. on the other hand, owing to the signal sent after channel gain can With detected, IQ imbalance parameter can also be estimated by sending training symbol, and this compensation scheme is than blind compensation operation Measure little, it is easy to accomplish, therefore it is widely used.Such as, impact unbalanced for the IQ in ofdm system, by based on estimation System-level algorithm carrys out compensating distortion, equalizes including least square (LS, least squares), and adaptive equalization, based on quick Fu The LS of vertical leaf transformation (FFT, fast fourier transform) and use adaptive channel estimation and special pilot tone believe Number pre-FFT correction, realize estimating accurately and rapidly and compensating, its method description be referred to document: A.Tarighat and A.H.Sayed.Joint compensation of transmitter and receiver impairments in OFDM systems [J] .IEEE Trans.Wireless Communications, 2007,6 (1): 240 247.

Radio-frequency front-end in high frequency communication system relaxes requirement unbalanced to IQ for reducing cost, or in prior art When cannot avoid more serious IQ imbalance with technique, it is necessary and crucial for carrying out IQ imbalance compensation in a base band.At present, Substantial amounts of IQ imbalance compensation algorithm is estimated based on the criterion such as traditional LS and compensates, and the most fully excavate training sequence from phase Close and association's correlation properties, and to assume to obtain preferable channel condition information (CSI, Channel State Information) Premised on.Make the training sequence of IQ imbalance compensation with Golay complementary series, study a kind of IQ based on Golay complementary series The method of imbalance compensation is one to be had novelty and important practical usage and has challenging task.

Summary of the invention

The invention provides in a kind of wireless communication system, IQ imbalance compensation method based on Golay complementary series, should First method sends the special word (UW) that continuous print is made up of Golay complementary series, then by the UW of transmission and connecing of correspondence thereof Receive data and do circular correlation, the compound letter affected by IQ imbalance parameter by correlated results is made some specific computings obtain Road, finally extracts the bigger efficient channel of power in compound channel and utilizes LS algorithm to calculate IQ imbalance compensation coefficient pair Reception data compensate.

It is an object of the invention to be achieved through the following technical solutions:

The method of IQ imbalance compensation based on Golay complementary series, comprises the following steps:

S1, structure training sequence to and send, including:

S11, constructing the Golay complementary series of a length of N to " a " and " b ", wherein Golay complementary series is two kinds of differences (a, b), (a b) has sequence pair the equal sequence pair of the length of element 1 and-1 compositionCharacter, C (x, y) represents arbitrary sequence x and the cyclic convolution of y,Represent vector Transposition computing, (x, kth (cyclic shift number) individual element y) is C Wherein sequence length N=2^M(M is integer), x_lAnd y_lRepresenting vector x and the l element of y respectively, " mod (l, N) " is that l is to N Remainder number operator；

S12, a cyclic shift N/4 backward in complementary " a " sequence of Golay is made to be designated as a_c, wherein, a_cAs special word (UW, Unique Word) imaginary part, special word is to carry out synchronizing or parameter estimation etc. at receiving terminal, at the tool that transmitting terminal sends Have some particular characteristics, for special sequence known to receiving terminal, wherein, UW is that receiving-transmitting sides is known and changeless, The UW value of each frame of signal is the most identical；

Complementary " b " sequence b of Golay that " a " sequence length described in S13 with S12 is identical, b is as the real part of UW；

S14, according to the real part described in S12 and S13 and imaginary part, constitute UW block, UW block isIt is denoted as UWa；

S15, repetition S11-S14, construct another UW blockIt is denoted as UWb；

S16, sending the training sequence (TS, Training Sequence) of time domain type at transmitting terminal, this training sequence is by even Continuous P UWa follows continuous P UWb composition closely；

S2, receiving terminal receive the training sequence pair described in S1, and the sequence received is circulated relevant place respectively Reason, including:

The time-domain received signal that S21, receiving terminal are affected by IQ imbalance is expressed asWherein, vector r Represent the signal not affected by IQ imbalance,X represents and does not adds Cyclic Prefix (CP, Cyclic Prefix) Time domain sends data,Represent the cyclic convolution of vector,Be a length of L equivalence discrete Channel, plural number α=cos (Δ φ)-j ε sin (Δ φ), plural number β=ε cos (Δ φ)+jsin (Δ φ) is by IQ amplitude and phase The uneven IQ imbalance parameter caused in position, [] * represents the conjugation of variable or vector,Representing that average is 0, variance is's Time domain white Gaussian noise (AWGN, Additive White Gaussian Noise)；

S22, order note y (1) are the reception signal of any one UWa between the 2nd to P-1, and y (2) is to appoint between the 2nd to P-1 The reception signal of one UWb of meaning, uses respectively at receiving terminalThe real part a of UWa again_cWith imaginary part b, y (1) and y (2) is followed Ring is correlated with, and circular correlation is as follows:

$\begin{array}{c}C(\sqrt{2}{a}_c,y(1\left)\right)=\mathrm{\α}g\⊗C(a_c,a_c)+j\mathrm{\α}h\⊗C(a_c,b)\\ +{\mathrm{\βh}}^{*}\×C(a_c,a_c)-{\mathrm{j\βh}}^{*}\⊗C(a_c,b)+w^{\′}\end{array}---\left(1\right)$

$\begin{array}{c}C(\sqrt{2}b,y(2\left)\right)=\mathrm{\α}h\⊗C(b,b)+j\mathrm{\α}h\⊗C(b,a_c)\\ +{\mathrm{\βh}}^{*}\⊗C(b,b)-{\mathrm{\βh}}^{*}\⊗C(b,a_c)+w^{\′}\end{array}---\left(2\right)$

$\begin{array}{c}C(\sqrt{2}b,y(1\left)\right)=\mathrm{\α}h\⊗C(b,a_c)+j\mathrm{\α}h\⊗C(b,b)\\ {\mathrm{\βh}}^{*}\⊗C(b,a_c)-{\mathrm{j\β}}^{*}\⊗C(b,b)+w^{\′\′}\end{array}---\left(1\right)$

Wherein, w ' (1), w ' (2), w " (1) and w " (2) represent a respectively_cWith in b Yu y (1)With in y (2)After circular correlation AWGN noise item；

S3, utilize a described in S1_cWith the auto-correlation of b and assist the relevant character having, i.e.

The circulation phase that S2 is obtained Close result and carry out specific following computing:

$\begin{array}{c}c\left(1\right)=\frac{1}{4N}\{C(a_c,y(1\left)\right)+C(b,y(2\left)\right)-j\[C(b,y(1\left)\right)+C(a_c,y(2\left)\right)\]\}\\ =\mathrm{\α}h+{\tilde{w}}_1\end{array}$

Obtain c (1) and c (2)；

S4, the c (1) and the c (2) that obtain according to S3 draw parameter lambda (λ=beta/alpha^*Represent the ratio of the multiple parameter of IQ imbalance.), Including:

S41, because α close to 1, β close to 0, select c (1) extract the efficient channel affected by IQ imbalance.Traversal Vector c (1) all elements, therefrom chooses the element that the square value of mould is maximum, it is designated as:Wherein, mould is again power；

S42, select prominent element c_max(1) after, the power of each element in relatively vectorial c (1) and c_max (1) size of the half of power: if the power of element compares c in c (1)_max(1) the one of power is medium-sized, then choose this element as Article one, effective compound channel, meanwhile, selects the element of same position from c (2), the element group again that c (1) and c (2) is chosen Synthesize new vectorWithThis process can be designated as:

$\left(\tilde{c}\right(1),\tilde{c}(2\left)\right)=\left\{\right(c_k\left(1\right),c_k\left(2\right)\left)\right|\∀k\∈\{0:N-1\}:\left|c_k\right(1){|}^2>0.5c_{max}(1\left)\right\};$

S43, orderFor new vectorWithLength, λ=beta/alpha^*Represent the ratio of the multiple parameter of IQ imbalance, utilize LS Algorithmic minimizing cost function:The estimated value obtaining parameter lambda is:

$\widehat{\mathrm{\λ}}=\frac{\mathrm{\β}}{{\mathrm{\α}}^{*}}=\frac{\underset{k=0}{\overset{\tilde{L}-1}{\Σ}}{\tilde{c}}_k\left(2\right){\tilde{c}}_k\left(1\right)}{\underset{k=0}{\overset{\tilde{L}-1}{\Σ}}|{\tilde{c}}_k\left(1\right){|}^2};$

S5, the estimated value of the parameter lambda obtained according to S4, compensate and receive the unbalanced impact of signal IQ: by the parameter lambda estimated Can compensate IQ imbalance with reception signal conjugation is: y_c=y-λ y^*=[(| α |²-|β|²)/α^*] r=γ r, wherein,

Further, it is integer that sequence length N described in S1 meets 3N/8 >=L, M, M >=3, and L is the length of equivalent dispersion channel Degree.

Further, a described in S1_cFor the Q road signal in I/Q signal, b is the I road signal in I/Q signal.

Further, P >=3 described in S1, P is integer.

The invention has the beneficial effects as follows: IQ imbalance compensation method based on Golay complementary series is first by complementary series pair One of them cyclic shift, at transmitting terminal using complementary series to as sending the real part of sequence and imaginary part modulation, connecing Receiving end utilizes the character that Golay complementary series auto-correlation is relevant with association, estimates IQ under conditions of requiring no knowledge about channel information Unbalanced multiple parameter, and then it is uneven to compensate IQ.Have only to simple relevant and some specific computings at receiving terminal, be not required to Want complicated matrix operations, be thus susceptible to realize.The present invention cannot only be applied in ofdm system, it is also possible to uses SC- In FDE system, range of application is wider.

Accompanying drawing explanation

Fig. 1 is that transmitting terminal physical layer of the present invention sends data structure diagram；

Fig. 2 is the illustraton of model that the present invention is affected by IQ imbalance；

Fig. 3 is present invention IQ based on Golay complementary series imbalance compensation algorithm flow chart；

Fig. 4 (a) is present invention difference in sighting distance (LOS) channel model that IEEE 802.15.ad standard channel defines Bit signal to noise ratio E_b/N₀(dB) performance chart.

Fig. 4 (b) is that the present invention is in non line of sight (NLOS) channel model that IEEE 802.15.ad standard channel defines Different bit signal to noise ratios E_b/N₀(dB) performance chart.

Detailed description of the invention

The concrete grammar step of the present invention be discussed in detail below with reference to accompanying drawing:

Fig. 1 is that transmitting terminal physical layer of the present invention sends data structure diagram.Training sequence is inserted in time domain sends data (TS), training sequence sends before transmitting data.Send the CP inserting UW composition equivalent data block between data.Used by this example UW be Golay sequence, UW extension after data block length N_b=512, data block CP length N_cp=64, now P=8.TS is by 8 Individual Uwa and 1 Uwa as Cyclic Prefix and the Uwb of a 8 and Uwb as Cyclic Prefix is constituted, and i.e. TS is by 8+1 UWa and 8+1 individual UWb is constituted.If sending user data it is:N_sIt it is user data Length.Length N inserted between user data_cpUW be: u=[u (0), u (1) ..., u (N_cp-1)]^T.I-th after UW extension Data blockSend after carrying out single-carrier modulated, its length N_b=N_s+N_cp.Equivalent dispersion channel impulse response (CIR, channel impulse response) is: h=[h (0), h (1) ..., h (L-1)]^T, L is channel length.Assume Ideal synchronisation, i-th data block is by AWGN vectorAdditive effect, wherein its m-th element w_i(m) be average be 0, side Difference isAWGN.After arriving receiving terminal, owing to being affected by IQ amplitude imbalance ε and unbalance in phase Δ φ, receive signal ForWherein, r_iThe signal that expression is not affected by IQ imbalance:It is uneven that α=cos (Δ φ)-j ε sin (Δ φ), β=ε cos (Δ φ)+jsin (Δ φ) illustrate receiving terminal IQ The impact (when Liang Ge branch is identical, α=1, β=0) that weighing apparatus docking is collected mail number.Remaining average is 0, and variance is AWGN.

Remove after its CP through N_bPoint FFT enters frequency domain, and obtaining frequency domain received data is

$Y_i\left(k\right)={\mathrm{\αX}}_i\left(k\right)H_i\left(k\right)+{\mathrm{\βX}}_i^{*}\left(k\right)H_i^{*}\left(k\right)+{\tilde{W}}_i\left(k\right),0\≤k\≤N_b-1$

In formula,It is the N of channel h_bPoint FFT, i.e. channel frequency domain response (CFR, Channel Frequency Response).In like manner,And N_iK () is h respectively^*、x_i、N with AWGN_b Point FFT.

Fig. 2 is the illustraton of model that the present invention is affected by IQ imbalance.The persistent period of channel estimation sequence x [n] is T.Base band Signal is through low pass filter ψ_T(t) filter out of band signal after up-conversion to carrier frequency ω_c.Output signal s_RFT () exists It is N that first amplifer stage of receiving front-end adds one-sided power spectrum density₀Additive white Gaussian noise (AWGN)Penetrate Frequently (RF) receives signal r_RFT () down-converts to baseband signal through complicated operation conversion, in order to avoid aliasing is through over-sampling frequency Rate is the low pass filter ψ of 1/T_RT () serial parallel afterwards conversion forms receiving sequence y [n].In figure, not mating of sending and receiving end LO, causes IQ is uneven.

Fig. 3 is present invention IQ based on Golay sequence imbalance compensation algorithm flow chart.First, by Golay complementary series To (a, the b) (a length of N (N=2 of a, b^M, M >=3)) structure two kinds of UW blocks, respectively UWa and UWb.The transmission signal of UWa isThe transmission signal of UWb isWherein, a_cIt it is complementary " a " sequence a of Golay The sequence formed after cyclic shift N/4 backward.The training sequence (TS) that transmitting terminal sends in the time domain is individual by continuous P (P >=3) UWa and UWb forms.Note y (1) be the reception signal of any one UWa between the 2nd to P-1, in like manner, y (2) be the 2nd to P-1 it Between the reception signal of any one UWb, at receiving terminal respectively with the real part a of UWa_cWith imaginary part b and y (1) and y (2) circular correlation Obtain c (1) and c (2), from c (1) and c (2), then extract efficient channelWithIQ is obtained not finally by LS algorithm After balanced compensated coefficient, reception data are compensated.Comprise the following specific steps that:

S1, structure training sequence to and send, including:

S11, constructing the Golay complementary series of a length of N to " a " and " b ", wherein Golay complementary series is two kinds of differences (a, b), (a b) has sequence pair the equal sequence pair of the length of element 1 and-1 compositionCharacter, C (x, y) represents arbitrary sequence x and the cyclic convolution of y,Represent vector Transposition computing, (x, kth (cyclic shift number) individual element y) is C Wherein sequence length N=2^M, x_lAnd y_lRepresenting vector x and the l element of y respectively, " mod (l, N) " is that the remainder number of N is transported by l Operator, it is integer that sequence length N meets 3N/8 >=L, M, M >=3, and L is the length of equivalent dispersion channel；

S12, a cyclic shift N/4 backward in complementary " a " sequence of Golay is made to be designated as a_c, wherein, a_cAs special word (UW, Unique Word) imaginary part, special word is to carry out synchronizing or parameter estimation etc. at receiving terminal, at the tool that transmitting terminal sends Have some particular characteristics, for special sequence known to receiving terminal, wherein, UW is that receiving-transmitting sides is known and changeless, The UW value of each frame of signal is the most identical, a_cFor the Q road signal in I/Q signal, b is the I road signal in I/Q signal；

Complementary " b " sequence b of Golay that " a " sequence length described in S13 with S12 is identical, b is as the real part of UW；

S14, according to the real part described in S12 and S13 and imaginary part, constitute UW block, UW block isIt is denoted as UWa；

S15, repetition S11-S14, construct another UW blockIt is denoted as UWb；

S16, sending the training sequence (TS, Training Sequence) of time domain type at transmitting terminal, this training sequence is by even Continuous P UWa follows continuous P UWb composition closely, and wherein, P >=3, P is integer；

S2, receiving terminal receive the training sequence pair described in S1, and the sequence received is circulated relevant place respectively Reason, including:

The time-domain received signal that S21, receiving terminal are affected by IQ imbalance is expressed asWherein, vector r Represent the signal not affected by IQ imbalance,X represents and does not adds Cyclic Prefix (CP, Cyclic Prefix) Time domain sends data,The cyclic convolution of expression vector, h=[h (0), h (1) ..., h (L-1)]^TIt it is the equivalence of a length of L Discrete channel, plural number α=cos (Δ φ)-j ε sin (Δ φ), plural number β=ε cos (Δ φ)+jsin (Δ φ) is by IQ amplitude The IQ imbalance parameter caused with unbalance in phase,Represent variable or the conjugation of vector,Representing that average is 0, variance is Time domain white Gaussian noise (AWGN, Additive White Gaussian Noise)；

S22, order note y (1) are the reception signal of any one UWa between the 2nd to P-1, and y (2) is to appoint between the 2nd to P-1 The reception signal of one UWb of meaning, uses respectively at receiving terminalThe real part a of UWa again_cWith imaginary part b, y (1) and y (2) is followed Ring is correlated with, and circular correlation is as follows:

$\begin{array}{c}C(\sqrt{2}{a}_c,y(1\left)\right)=\mathrm{\α}h\⊗C(a_c,a_c)+j\mathrm{\α}h\⊗C(a_c,b)\\ +{\mathrm{\βh}}^{*}\⊗C(a_c,a_c)-{\mathrm{j\βh}}^{*}\⊗C(a_c,b)+w^{\′}\end{array}---\left(1\right)$

$\begin{array}{c}C(\sqrt{2}b,y(2\left)\right)=\mathrm{\α}h\⊗C(b,b)+j\mathrm{\α}h\⊗C(b,a_c)\\ +{\mathrm{\βh}}^{*}\⊗C(b,b)-{\mathrm{\βh}}^{*}\⊗C(b,a_c)+w^{\′}\end{array}---\left(2\right)$

$\begin{array}{c}C(\sqrt{2}b,y(1\left)\right)=\mathrm{\α}h\⊗C(b,a_c)+j\mathrm{\α}h\⊗C(b,b)\\ +{\mathrm{\βh}}^{*}\⊗C(b,a_c)-{\mathrm{j\βh}}^{*}\⊗C(b,b)+w^{\′\′}\end{array}---\left(1\right)$

Wherein, w ' (1), w ' (2), w " (1) and w " (2) represent a respectively_cWith in b Yu y (1)With in y (2)After circular correlation AWGN noise item；

S3, utilize a described in S1_cWith the auto-correlation of b and assist the relevant character having, i.e.

The circulation phase that S2 is obtained Close result and carry out specific following computing:

$\begin{array}{c}c\left(1\right)=\frac{1}{4N}\{C(a_c,y(1\left)\right)+C(b,y(2\left)\right)-j\[C(b,y(1\left)\right)+C(a_c,y(2\left)\right)\]\}\\ =\mathrm{\α}h+{\tilde{w}}_1\end{array}$

Obtain c (1) and c (2)；

S4, the c (1) and the c (2) that obtain according to S3 draw parameter lambda (λ=beta/alpha^*Represent the ratio of the multiple parameter of IQ imbalance.), Including:

S41, because α close to 1, β close to 0, select c (1) extract the efficient channel affected by IQ imbalance.Traversal Vector c (1) all elements, therefrom chooses the element that the square value of mould is maximum, it is designated as:Wherein, mould is again power；

S42, select prominent element c_max(1) after, the power of each element in relatively vectorial c (1) and c_max (1) size of the half of power: if the power of element compares c in c (1)_max(1) the one of power is medium-sized, then choose this element as Article one, effective compound channel, meanwhile, selects the element of same position from c (2), the element group again that c (1) and c (2) is chosen Synthesize new vectorWithThis process can be designated as:

$\left(\tilde{c}\right(1),\tilde{c}(2\left)\right)=\left\{\right(c_k\left(1\right),c_k\left(2\right)\left)\right|\∀k\∈\{0:N-1\}:\left|c_k\right(1){|}^2>0.5c_{max}(1\left)\right\};$

S43, orderFor new vectorWithLength, λ=beta/alpha^*Represent the ratio of the multiple parameter of IQ imbalance, utilize LS Algorithmic minimizing cost function:The estimated value obtaining parameter lambda is:

$\widehat{\mathrm{\λ}}=\frac{\mathrm{\β}}{{\mathrm{\α}}^{*}}=\frac{\underset{k=0}{\overset{\tilde{L}-1}{\Σ}}{\tilde{c}}_k\left(2\right){\tilde{c}}_k\left(1\right)}{\underset{k=0}{\overset{\tilde{L}-1}{\Σ}}|{\tilde{c}}_k\left(1\right){|}^2};$

S5, the estimated value of the parameter lambda obtained according to S4, compensate and receive the unbalanced impact of signal IQ: by the parameter lambda estimated Can compensate IQ imbalance with reception signal conjugation is: y_c=y-λ y^*=[(| α |²-|β²|)/α^*] r=γ r, wherein,

Fig. 4 (a) and Fig. 4 (b) is that the transmitting terminal physical layer using Fig. 1 sends data structure diagram, the IQ imbalance model of Fig. 2 Structure and the algorithm flow of Fig. 3, be applied in concrete communication system, chooses SC-FDE system here as an example, imitative The inventive algorithm really obtained bit error rate (BER) performance chart in SC-FDE system.Wherein, Fig. 4 (a) and Fig. 4 (b) It is illustrated respectively in sighting distance (LOS) channel model and non line of sight (NLOS) channel model of the definition of IEEE 802.15.ad standard channel Middle different bit signal to noise ratio E_b/N₀(dB) performance chart.The analogue system of this example is belonging to high-frequency high-speed ultra-wideband communications system System, its main simulation parameter is: carrier frequency is 60GHz, and bit rate is 1.76Gbps, 16QAM modulation, sends and reception is roll-offed The roll-off factor of wave filter is 0.25, and system bandwidth is 2.16GHz, and the IQ imbalance parameter of sending and receiving end is all ε=1dB, Δ φ =10⁰.From Fig. 4 (a) and Fig. 4 (b) it will be seen that during not to IQ imbalance compensation, the poor performance of system, and to IQ After imbalance compensation, systematic function improve it is obvious that close to IQ uneven not in the presence of performance.

Claims (2)

1. an IQ imbalance compensation method based on Golay complementary series, it is characterised in that: its step is as described below:

S1, structure training sequence to and send, including:

S11, constructing the Golay complementary series of a length of N to " a " and " b ", wherein Golay complementary series is two kinds of different elements 1 (a, b), (a b) has sequence pair the sequence pair equal with the length of-1 compositionProperty Matter, (x y) represents arbitrary sequence x and the cyclic convolution of y, [] to C^TRepresent the transposition computing of vector, C (x, kth element y) ForWherein, k is cyclic shift number, sequence length N=2^MAnd 3N/8 >= L, M are integer, M >=3, and L is the length of equivalent dispersion channel, x_lAnd y_lRepresent vector x and the l element of y respectively, " mod (l, N) " it is the l remainder number operator to N；

S12, a cyclic shift N/4 backward in complementary " a " sequence of Golay is made to be designated as a_c, wherein, a_cAs special word (UW, Unique Word) imaginary part, special word is to carry out synchronizing or parameter estimation etc. at receiving terminal, at the tool that transmitting terminal sends Have some particular characteristics, for special sequence known to receiving terminal, wherein, UW is that receiving-transmitting sides is known and changeless, The UW value of each frame of signal is the most identical, a_cFor the Q road signal in I/Q signal, b is the I road signal in I/Q signal；

Complementary " b " sequence b of Golay that " a " sequence length described in S13 with S12 is identical, b is as the real part of UW；

S14, according to the real part described in S12 and S13 and imaginary part, constitute UW block, UW block isIt is denoted as UWa；

S15, repetition S11-S14, construct another UW blockIt is denoted as UWb；

S16, transmitting terminal send time domain type training sequence (TS, Training Sequence), this training sequence is by continuous P Individual UWa follows continuous P UWb composition closely；

S2, receiving terminal receive the training sequence pair described in S1, and the sequence received is circulated relevant treatment respectively, bag Include:

The time-domain received signal that S21, receiving terminal are affected by IQ imbalance is expressed asWherein, vector r represents The signal not affected by IQ imbalance,X represents the time domain not adding Cyclic Prefix (CP, Cyclic Prefix) Send data,The cyclic convolution of expression vector, h=[h (0), h (1) ..., h (L-1)]^TBe a length of L equivalence discrete Channel, plural number α=cos (Δ φ)-j ε sin (Δ φ), plural number β=ε cos (Δ φ)+jsin (Δ φ) is by IQ amplitude and phase The uneven IQ imbalance parameter caused in position, []^*Represent variable or the conjugation of vector,Representing that average is 0, variance is's Time domain white Gaussian noise (AWGN, Additive White Gaussian Noise)；

S22, order note y (1) are the reception signal of any one UWa between the 2nd to P-1, and y (2) is any one between the 2nd to P-1 The reception signal of individual UWb, uses respectively at receiving terminalThe real part a of UWa again_cWith imaginary part b, y (1) and y (2) is circulated phase Closing, circular correlation is as follows:

$\begin{array}{c}C(\sqrt{2}{a}_c,y(1\left)\right)=\mathrm{\α}h\⊗C(a_c,a_c)+j\mathrm{\α}h\⊗C(a_c,b)\\ +{\mathrm{\βh}}^{*}\⊗C(a_c,a_c)-{\mathrm{j\βh}}^{*}\⊗C(a_c,b)+w^{\′}\left(1\right)\end{array}$

$\begin{array}{c}C(\sqrt{2}b,y(2\left)\right)=\mathrm{\α}h\⊗C(b,b)+j\mathrm{\α}h\⊗C(b,a_c)\\ +{\mathrm{\βh}}^{*}\⊗C(b,b)-{\mathrm{j\βh}}^{*}\⊗C(b,a_c)+w^{\′}\left(2\right)\end{array}$

$\begin{array}{c}C(\sqrt{2}b,y(1\left)\right)=\mathrm{\α}h\⊗C(b,a_c)+j\mathrm{\α}h\⊗C(b,b)\\ +{\mathrm{\βh}}^{*}\⊗C(b,a_c)-{\mathrm{j\βh}}^{*}\⊗C(b,b)+w^{\′\′}\left(1\right)\end{array}$

Wherein, w ' (1), w ' (2), w " (1) and " (2) represent a to w respectively_cWith in b Yu y (1)With in y (2)AWGN after circular correlation Noise item；

S3, utilize a described in S1_cWith the auto-correlation of b and assist the relevant character having, i.e.

The circular correlation knot that S2 is obtained Fruit carries out specific following computing:

$\begin{array}{c}c\left(1\right)=\frac{1}{4N}\{C(a_c,y(1\left)\right)+C(b,y(2\left)\right)-j\[C(b,y(1\left)\right)+C(a_c,y(2\left)\right)\]\}\\ =\mathrm{\α}h+{\tilde{w}}_1\end{array}$

Obtain c (1) and c (2)；

S4, the c (1) and the c (2) that obtain according to S3 draw parameter lambda (λ=beta/alpha^*Represent the ratio of the multiple parameter of IQ imbalance), including:

S41, because α close to 1, β close to 0, select c (1) extract the efficient channel affected by IQ imbalance, time Go through vector c (1) all elements, therefrom choose the element that the square value of mould is maximum, it is designated as:Wherein, mould is again power；

S42, select prominent element c_max(1) after, the power of each element in relatively vectorial c (1) and c_max(1) merit The size of the half of rate: if the power of element compares c in c (1)_max(1) the one of power is medium-sized, then choose this element as one Effectively compound channel, meanwhile, selects the element of same position from c (2), and the element that c (1) and c (2) is chosen is reassembled into New vectorWithThis process can be designated as:

$\left(\tilde{c}\right(1),\tilde{c}(2\left)\right)=\left\{\right(c_k\left(1\right),c_k\left(2\right)\left)\right|\∀k\∈\{0:N-1\}:{\left|c_k\left(1\right)\right|}^2>0.5c_{max}\left(1\right)\};$

S43, orderFor new vectorWithLength, λ=beta/alpha^*Represent the ratio of the multiple parameter of IQ imbalance, utilize LS algorithm Minimize cost function:The estimated value obtaining parameter lambda is:

$\widehat{\mathrm{\λ}}=\frac{\mathrm{\β}}{{\mathrm{\α}}^{*}}=\frac{\underset{k=0}{\overset{\tilde{L}-1}{\Σ}}{\tilde{c}}_k\left(2\right){\tilde{c}}_k\left(1\right)}{\underset{k=0}{\overset{\tilde{L}-1}{\Σ}}{\left|{\tilde{c}}_k\left(1\right)\right|}^2};$

S5, the estimated value of the parameter lambda obtained according to S4, compensate and receive the unbalanced impact of signal IQ: by the parameter lambda estimated Can compensate IQ imbalance with reception signal conjugation is: y_c=y-λ y^*=[(| α |²-|β|²)/α^*] r=γ r, wherein,

A kind of IQ imbalance compensation method based on Golay complementary series the most according to claim 1, it is characterised in that: P >=3 described in S1, P is integer.