CN103475605A - Channel estimation method based on user special reference signal of 3GPPLTE-A downlink system - Google Patents

Abstract

The invention discloses a channel estimation method based on a user special reference signal of a 3GPPLTE-A downlink system. The user special reference signal carried by a resource block is used for carrying out LS estimation on a subcarrier at the position of the reference signal at first, the minimum mean square error algorithm is used for carrying out frequency domain interpolation and then carrying out time domain replication interpolation, and therefore the channel frequency responses of all the subcarriers on the whole resource block are obtained. According to the channel estimation method based on the user special reference signal of the 3GPPLTE-A downlink system, orthogonal superposition codes are adopted to carry out multiplexing, and orthorhombic reference signals at the same position are processed to achieve the channel estimation under eight-antenna transmission. In addition, the channel estimation method based on the user special reference signal of the 3GPPLTE-A downlink system carries out effective segmentation on LMMSE algorithm-related matrixes to reduce the operation complexity of the algorithm, and achieves the channel estimation process identical with the cell special reference signals, and the complexity of processing and controlling is reduced.

Description

Channel estimation methods based on user's DRS (Dedicated Reference Signal) in a kind of 3GPPLTE-A downlink system

Technical field

The present invention relates to the channel estimation technique field in communication system, be specifically related to a kind of 3GPPLTE-A channel estimation methods.

Background technology

LTE-A is the abbreviation of LTE-Advanced, the follow-up evolution of LTE technology, its objective is higher demand and Geng Duo application for meeting the wireless communications market coming years, meet and surpass the advanced world and move (International Mobile Telecommunications-Advanced, IMT-Advanced) demand also will keep the backwards compatibility preferably to LTE simultaneously.

In the LTE-A system, adopted orthogonal frequency division multiplexi as its key technology, need to do channel estimating by cell-specific (Cell-specific) and special-purpose (UE-specific) reference signal of user (RS), although UE-specific reference signal and Cell-specific reference signal be scattered time domain and the frequency domain of being distributed in all, but in the LTE-A system, the antenna for base station number is supported at most 8 antennas, the Cell-specific reference signal is relevant with antenna port, when antenna number increases, for the RE quantity of carrying the Cell-specific reference signal, also to increase, and the expense of UE-specific reference signal is by the order decision of the transmission of user data, adopt code minute mode: orthogonal superposition code OCC(orthogonalcoveringcode) coding, reduce the RE number of the actual use of UE-specific reference signal.

In the channel estimation method based on the UE-specific reference signal, transmitting terminal inserts all known UE-specific reference signals of transmitting terminal and receiving terminal in fixing position, then receiving terminal goes out the channel frequency response of each OFDM symbol by the reception Signal estimation of processing these positions.Channel estimation methods based on user's DRS (Dedicated Reference Signal) in the 3GPPLTE-A downlink system roughly can be divided into least square (Least-Squares, LS) and least mean-square error (LinearMinimumMean-SquareError, LMMSE) two class methods.These two class methods are all, on frequency domain, each subcarrier is carried out to channel estimating, and wherein, the LS channel estimation methods does not need channel information, and it is the easiest to realize; The LMMSE channel estimation methods has utilized the channel statistical informations such as correlation between subcarrier and signal to noise ratio, and estimated performance is better, is widely used in the channel estimating of MIMO-OFDM.But this method of estimation need to be extracted the UE-specific reference signal on different layers from the UE-specific reference signal received, and then completes channel estimation works with local reference signal, and computing is more complicated.

Summary of the invention

Technical problem to be solved by this invention is to provide the channel estimation methods based on user's DRS (Dedicated Reference Signal) in a kind of LTE-A downlink system, at first the present invention utilizes the user's DRS (Dedicated Reference Signal) (RS) carried on Resource Block, subcarrier to the reference signal position carries out the LS estimation, then utilize least-mean-square error algorithm to carry out frequency domain interpolation, carry out again time domain and copy interpolation, obtain the channel frequency response of all subcarriers on whole Resource Block.On identical resource particle, adopt the orthogonal superposition code to carry out multiplexing, by processing the reference signal of quadrature on same position, realize the channel estimating under eight antenna transmission, frequency domain interpolation adopts the ALMMSE algorithm based on LMMSE simultaneously, further reduces the computational complexity in the frequency domain interpolation process.

The technical scheme that the present invention solves the problems of the technologies described above is: the channel estimation methods based on user's DRS (Dedicated Reference Signal) in a kind of 3GPPLTE-A downlink system, according to the UE-specific reference signal of carrying on Resource Block, the subcarrier of reference signal position is carried out to channel estimating, obtain thus the sub-carrier channels estimated value on the OFDM symbol of UE-specific reference signal place; Utilize the sub-carrier channels estimated value on the OFDM symbol to obtain the channel frequency domain response of UE-specific reference signal position by frequency domain interpolation, adopt time domain to copy interpolation and obtain the channel frequency response on other OFDM symbol, all subcarriers on Resource Block are carried out to channel estimating.

The frequency domain UE-specific reference signal produced by this locality $V_m^{\left(k\right)},k=\mathrm{0,1},...,K-1,m\∈\{\mathrm{1,2},...,M\},M\≤4$ With the actual frequency domain UE-specific reference signal r received ^(k), k=0,1 ..., K-1, according to formula:

obtain the channel estimation value of K UE-specific reference signal position on the m layer

wherein, the quantity that K is UE-specific reference signal subcarrier, the number of plies that M is the stack of UE-specific reference signal position.

Carrying out frequency domain interpolation specifically comprises: to autocorrelation matrix

be divided into a series of sub-block autocorrelation matrixes, then each sub-block autocorrelation matrix is averaged

according to formula: ${\hat{H}}_{\mathrm{LMMSE},n}={\stackrel{\‾}{R}}_{{\mathrm{HH}}_p}^{\left(L\right)}{({\stackrel{\‾}{R}}_{H_p{H}_p}^{\left(L\right)}+I_p^{\left(L\right)}\frac{\mathrm{\β}}{\mathrm{SNR}})}^{-1}{\hat{H}}_{\mathrm{LS},n}$ Obtain the channel frequency response of all subcarriers of n sub-block; Integrate the channel frequency response value of each sub-block subcarrier, according to formula: $H_{\mathrm{ALMMSE}}={[{\hat{H}}_{\mathrm{LMMSE},1}^T,{\hat{H}}_{\mathrm{LMMSE},2}^T,...,{\hat{H}}_{\mathrm{LMMSE},n}^T]}^T$ Obtain the channel frequency response of all subcarriers on the OFDM symbol of UE-specific reference signal place, wherein,

mean the cross-correlation matrix after the interior all subcarriers of each sub-block and UE-specific reference signal position subcarrier are averaged, β is constant, and SNR is average signal-to-noise ratio,

for unit matrix,

it is the channel frequency response of n sub-block UE-specific reference signal position.OFDM symbol for not having the UE-specific reference signal to distribute, by copying the channel frequency response of subcarrier on the OFDM symbol of UE-specific reference signal place, obtain the channel frequency response on other OFDM symbol.When local frequency domain UE-specific reference signal

with the actual frequency domain UE-specific reference signal r received ^(k)=[r ^{(6, k)}, r ^{(7, k)}, r ^{(13, k)}, r ^{(14, k}], according to formula: ${\hat{H}}_{\mathrm{LS},m}^{\left(k\right)}=\frac{r^{(6,k)}{\left(s_m^{(6,k)}\right)}^H+r^{(7,k)}{\left(s_m^{(7,k)}\right)}^H+r^{(13,k)}{\left(s_m^{(13,k)}\right)}^H+r^{(14,k)}{\left(s_m^{(14,k)}\right)}^H}{s_m^{(6,k)}{\left(s_m^{(6,k)}\right)}^H+s_m^{(7,k)}{\left(s_m^{(7,k)}\right)}^H+s_m^{(13,k)}{\left(s_m^{(13,k)}\right)}^H+s_m^{(14,k)}{\left(s_m^{(14,k)}\right)}^H}$ Obtain the LS estimation of the upper reference signal of m straton carrier wave k position, wherein,

mean the local reference signal on m straton carrier wave k, r ^{(l, k)}mean the receiving symbol of the upper reference signal of receiving terminal subcarrier k position, l means the position of reference signal place OFDM symbol, l ∈ { 6,7,13,14}.

The channel estimation methods that the present invention proposes adopts the orthogonal superposition code (orthogonalcoveringcode of design on the same asset particle, OCC) carry out multiplexing, by processing the reference signal of quadrature on same position, realize the channel estimating under eight antenna transmission, in addition, the present invention effectively cuts apart to LMMSE algorithm correlation matrix the computational complexity that reduces algorithm, simultaneously, realize the channel estimating flow process consistent with cell special reference, reduced the complexity of processing and controlling.In the LS estimation procedure, there is no directly to extract the UE-specific reference signal on different layers from the UE-specific reference signal received, and then complete channel estimation works with local reference signal, but directly utilize the UE-specific reference signal and the local UE-specific reference signal that receive on same subcarrier jointly to complete the channel estimating at subcarrier place, adopt the ALMMSE method of estimation in the frequency domain interpolation process, utilize the interference of correlation noise reduction of subcarrier and the complexity that reduces the LMMSE computing by the mode of piecemeal.

The accompanying drawing explanation

The channel estimation methods schematic flow sheet of Fig. 1 based on user's DRS (Dedicated Reference Signal);

The channel estimation methods principle schematic of Fig. 2 based on user's DRS (Dedicated Reference Signal);

The distribution map of Fig. 3 UE-specific reference signal in Resource Block;

Fig. 4 ALMMSE frequency domain interpolation autocorrelation matrix piecemeal schematic diagram.

Embodiment

The present invention is directed to the 3GPPLTE-A downlink system, propose the channel estimation methods based on user's DRS (Dedicated Reference Signal) in a kind of 3GPPLTE-A downlink system, adopt the channel estimation method that LS estimates and time-frequency domain LMMSE estimates that uses orthogonal code on the same asset particle.At first utilize LS to estimate to obtain the channel response value of UE-specific reference signal position on different layers, then utilize least mean-square error (ApproximateLMMSE) ALMMSE to estimate to obtain the channel response value of data subcarrier on whole Resource Block.On the same asset particle, adopt the orthogonal superposition code to carry out multiplexing, process the UE-specific reference signal of quadrature on same position, realized the channel estimating under eight antenna transmission, adopt the ALMMSE algorithm to carry out interpolation simultaneously, utilize the impact of the correlation noise reduction between subcarrier, improve the accuracy of channel estimating; , the autocorrelation matrix in the LMMSE algorithm is cut apart simultaneously, respectively the Resource Block after cutting apart is carried out to the LMMSE estimation, thereby reduced the computational complexity of LMMSE algorithm.

Wherein LS estimates specifically can adopt following method to realize, the UE-specific reference signal produced according to this locality $V_m^{\left(k\right)},k=\mathrm{0,1},...,K-1,m\∈\{\mathrm{1,2},...,M\},M\≤4$ With the actual frequency domain UE-specific reference signal r received ^(k), k=0,1 ..., K-1, used least square method to obtain the channel frequency response value of UE-specific reference signal position on the m layer to the subcarrier of UE-specific reference signal position

${\hat{H}}_{\mathrm{LS},m}^{\left(k\right)}=\frac{<r^{\left(k\right)},V_m^{\left(k\right)}>}{{\left|\right|V_m^{\left(k\right)}\left|\right|}^2}---\left(1\right)$

In formula, $V_m^{\left(k\right)}=[s_m^{(6,k)},s_m^{(7,k)},s_m^{(13,k)},s_m^{(14,k)}],r^{\left(k\right)}=[r^{(6,k)},r^{(7,k)},r^{(13,k)},r^{(14,k)}],$ K means the quantity of UE-specific reference signal subcarrier, and M means the number of plies of UE-specific reference signal position stack,

mean the local reference signal on m straton carrier wave k, r ^{(l, k)}mean the receiving symbol of the upper reference signal of receiving terminal subcarrier k position, l means the position of UE-specific reference signal place OFDM symbol, l ∈ { 6,7,13,14}.On the m layer, the channel frequency response value of UE-specific reference signal position is:

${\hat{H}}_{\mathrm{LS},m}^{\left(k\right)}=\frac{r^{(6,k)}{\left(s_m^{(6,k)}\right)}^H+r^{(7,k)}{\left(s_m^{(7,k)}\right)}^H+r^{(13,k)}{\left(s_m^{(13,k)}\right)}^H+r^{(14,k)}{\left(s_m^{(14,k)}\right)}^H}{s_m^{(6,k)}{\left(s_m^{(6,k)}\right)}^H+s_m^{(7,k)}{\left(s_m^{(7,k)}\right)}^H+s_m^{(13,k)}{\left(s_m^{(13,k)}\right)}^H+s_m^{(14,k)}{\left(s_m^{(14,k)}\right)}^H}---\left(2\right)$

Frequency domain interpolation is based on the LMMSE algorithm, and expression formula is as follows:

${\hat{H}}_{\mathrm{LMMSE}}=R_{{\mathrm{HH}}_p}{(R_{H_p{H}_p}+I_{N_p}\frac{\mathrm{\&beta;}}{\mathrm{SNR}})}^{-1}{\hat{H}}_{\mathrm{LS},n}---\left(3\right)$

According to correlation bandwidth, define

$B_c\&ap;\frac{1}{5{\mathrm{\&tau;}}_{\mathrm{rms}}}---\left(4\right)$

Channel H is divided into to the sub-vector that M length is L, and L<<N,

the length of L depends on the correlation bandwidth of channel, B _c/ Δ _f≈ L (Δ _fthe width that means subcarrier) or be set as a fixed value, τ _rmsthe root mean square that means channel delay.For reducing LMMSE algorithm computation complexity, by autocorrelation matrix in formula (3)

cut apart, and got the average of each sub-block autocorrelation matrix, obtained

lMMSE estimated value after each piecemeal is as follows:

${\hat{H}}_{\mathrm{LMMSE},n}={\stackrel{\&OverBar;}{R}}_{{\mathrm{HH}}_p}^{\left(L\right)}{({\stackrel{\&OverBar;}{R}}_{H_p{H}_p}^{\left(L\right)}+I_p^{\left(L\right)}\frac{\mathrm{\&beta;}}{\mathrm{SNR}})}^{-1}{\hat{H}}_{\mathrm{LS},n}---\left(5\right)$

In formula (5),

mean the autocorrelation matrix after each sub-block UE-specific reference signal position subcarrier is averaged,

mean the cross-correlation matrix after the interior all subcarriers of each sub-block and UE-specific reference signal position subcarrier are averaged, β is the constant determined by signal constellation (in digital modulation) figure, and SNR is average signal-to-noise ratio,

for unit matrix,

be the channel frequency response of n sub-block UE-specific reference signal position,

it is the channel frequency response of all subcarriers of n sub-block.

Then integrate the channel frequency response value of each sub-block subcarrier, obtain the channel frequency response of all subcarriers on the OFDM symbol of UE-specific reference signal place:

$H_{\mathrm{ALMMSE}}={[{\hat{H}}_{\mathrm{LMMSE},1}^T,{\hat{H}}_{\mathrm{LMMSE},2}^T,...,{\hat{H}}_{\mathrm{LMMSE},n}^T]}^T---\left(6\right)$

According to

known, be positioned at the UE-specific reference signal same subcarrier of living on different OFDM symbols, therefore the channel transfer function on same subcarrier is identical, so the channel estimation value on same subcarrier on all OFDM symbols is identical with the channel frequency domain response value on the subcarrier of UE-specific reference signal place.Therefore, the OFDM symbol for not having the UE-specific reference signal to distribute, by copying the channel frequency response of subcarrier on the OFDM symbol of UE-specific reference signal place, obtain the channel frequency response on other OFDM symbol.

Below in conjunction with accompanying drawing, the channel estimation methods based on user's DRS (Dedicated Reference Signal) in the LTE-A downlink system is described, so that those skilled in the art understands the present invention better.

Channel estimation methods schematic flow sheet based on user's DRS (Dedicated Reference Signal) in LTE-A downlink system of the present invention as shown in Figure 1.

S101, according to the UE-specific reference signal of carrying on Resource Block, the subcarrier of UE-specific reference signal position is carried out to channel estimating;

S102, according to the sub-carrier channels estimated value of UE-specific reference signal position, the subcarrier on the OFDM symbol of UE-specific reference signal place is carried out to channel estimating;

S103, utilize the channel estimation value of all subcarriers on the OFDM symbol of UE-specific reference signal place, obtain the channel frequency response value of all subcarriers on whole bandwidth.

Concrete steps are as follows:

Step S101 is specially, and to the user's DRS (Dedicated Reference Signal) carried on Resource Block, uses least square method to obtain the channel estimation value of user's DRS (Dedicated Reference Signal) position be illustrated in figure 2 the channel estimation methods principle schematic based on user's DRS (Dedicated Reference Signal).The frequency domain UE-specific reference signal produced by this locality $V_m^{\left(k\right)},k=\mathrm{0,1},...,K-1,m\&Element;\{\mathrm{1,2},...,M\},M\&le;4$ With the actual frequency domain UE-specific reference signal r received ^(k), k=0,1 ..., K-1, wherein, M means the number of plies of UE-specific reference signal position stack, K means UE-specific reference signal number of subcarriers, according to formula: ${\hat{H}}_{\mathrm{LS},m}^{\left(k\right)}=\frac{<r^{\left(k\right)},V_m^{\left(k\right)}>}{{\left|\right|V_m^{\left(k\right)}\left|\right|}^2}---\left(6\right)$ Obtain the channel estimating of K UE-specific reference signal position on the m layer.According to formula:

${\hat{H}}_{\mathrm{LS},m}^{\left(k\right)}=\frac{r^{(6,k)}{\left(s_m^{(6,k)}\right)}^H+r^{(7,k)}{\left(s_m^{(7,k)}\right)}^H+r^{(13,k)}{\left(s_m^{(13,k)}\right)}^H+r^{(14,k)}{\left(s_m^{(14,k)}\right)}^H}{s_m^{(6,k)}{\left(s_m^{(6,k)}\right)}^H+s_m^{(7,k)}{\left(s_m^{(7,k)}\right)}^H+s_m^{(13,k)}{\left(s_m^{(13,k)}\right)}^H+s_m^{(14,k)}{\left(s_m^{(14,k)}\right)}^H}---\left(7\right)$

The LS that obtains UE-specific reference signal on the m layer estimates.

The wherein processing mode of one deck of below take is processed and is analyzed description the LS estimated value as example, and the processing mode of other layer is identical.

Step S102 is specially, and according to the channel estimation value of UE-specific reference signal position, utilizes signal to noise ratio and channel correlation matrix information, adopts approximate LMMSE channel estimation method, obtains the channel estimating of UE-specific reference signal place OFDM symbol

Use is based on the LMMSE method, and traditional LMMSE channel estimation in frequency domain algorithm expression formula is as follows:

${\hat{H}}_{\mathrm{LMMSE}}=R_{{\mathrm{HH}}_p}{(R_{H_p{H}_p}+I_{N_p}\frac{\mathrm{\&beta;}}{\mathrm{SNR}})}^{-1}{\hat{H}}_{\mathrm{LS},n}---\left(8\right)$

Because LMMSE algorithm computational complexity is higher, need a large amount of memory spaces in estimating in real time, unrealistic concerning UE.In order to reduce computation complexity, by autocorrelation matrix

be divided into the submatrix that dimension is less, submatrix is got to its average average submatrix ${\stackrel{\&OverBar;}{R}}_{H_p{H}_p}^{\left(L\right)}.$

Channel matrix H is divided into to the sub-vector that M length is L, and the length of L depends on the correlation bandwidth of channel and the width Delta of subcarrier _f, according to formula: B _c/ Δ _f≈ L is definite, or is set as a fixed value, and wherein, correlation bandwidth is according to the root mean square τ of channel delay _rmscalling formula determines: $B_c\&ap;\frac{1}{5{\mathrm{\&tau;}}_{\mathrm{rms}}}---\left(9\right).$ Consider that the outer low correlation element of correlation bandwidth is less to systematic influence, original autocorrelation matrix R _hHbe divided into M sub-autocorrelation matrix as shown in Figure 4, for unnecessary, each sub-block is carried out in traditional LMMSE channel estimation in frequency domain algorithm

computing, to the M after cutting apart a sub-autocorrelation matrix

be averaged, obtain

according to formula: ${\hat{H}}_{\mathrm{LMMSE},n}={\stackrel{\&OverBar;}{R}}_{{\mathrm{HH}}_p}^{\left(L\right)}{({\stackrel{\&OverBar;}{R}}_{H_p{H}_p}^{\left(L\right)}+I_p^{\left(L\right)}\frac{\mathrm{\&beta;}}{\mathrm{SNR}})}^{-1}{\hat{H}}_{\mathrm{LS},n}---\left(10\right)$ Average autocorrelation matrix after each piecemeal is carried out to the LMMSE estimation.

After the channel frequency response that obtains respectively each piecemeal subcarrier, the channel frequency response that integration obtains all subcarriers on the OFDM symbol of UE-specific reference signal place is:

$H_{\mathrm{ALMMSE}}={[{\hat{H}}_{\mathrm{LMMSE},1}^T,{\hat{H}}_{\mathrm{LMMSE},2}^T,...,{\hat{H}}_{\mathrm{LMMSE},n}^T]}^T---\left(11\right)$

Step S103 is specially, according to

known, be positioned at the UE-specific reference signal same subcarrier of living on different OFDM symbols, therefore the channel transfer function on same subcarrier is identical, so the channel estimation value on same subcarrier on all OFDM symbols is identical with the channel frequency domain response value on the subcarrier of UE-specific reference signal place.Therefore, by the sub-carrier channels frequency response on the OFDM symbol of UE-specific reference signal place, copied, obtained the channel frequency response on all OFDM symbols in Fig. 3.

Channel estimation methods based on user's DRS (Dedicated Reference Signal) in a kind of LTE-A system provided by the invention, the UE-specific reference signal distribution situation of carrying according to Resource Block, UE-specific reference signal on each layer is carried out to channel estimating, then adopt the ALMMSE algorithm with utilizing the channel correlation properties that can reduce the LMMSE algorithm complex to carry out frequency domain interpolation, again the sub-carrier channels frequency response on the OFDM symbol of UE-specific reference signal place is copied, obtained the channel frequency response on whole Resource Block.Thereby realized the channel estimating under eight antenna transmission, also realized the channel estimating flow process consistent with cell special reference, reduced the complexity of processing and controlling simultaneously.

Claims (6)

1. the channel estimation methods based on user's DRS (Dedicated Reference Signal) in a 3GPPLTE-A downlink system, it is characterized in that, comprise step: according to the UE-specific reference signal of carrying on Resource Block, the subcarrier of reference signal position is carried out to channel estimating, obtain thus the sub-carrier channels estimated value on the OFDM symbol of UE-specific reference signal place; Utilize the sub-carrier channels estimated value on the OFDM symbol to obtain the channel frequency response of UE-specific reference signal position by frequency domain interpolation, adopt time domain to copy interpolation and obtain the channel frequency response on other OFDM symbol, all subcarriers on Resource Block are carried out to channel estimating.

2. channel estimation methods as claimed in claim 1, is characterized in that, the subcarrier of described UE-specific reference signal position is carried out to channel estimating, is specially: the frequency domain UE-specific reference signal produced by this locality $V_m^{\left(k\right)},k=\mathrm{0,1},...,K-1,m\&Element;\{\mathrm{1,2},...,M\},M\&le;4$ With the actual frequency domain UE-specific reference signal r received ^(k), k=0,1 ..., K-1, according to formula:

obtain the channel estimation value of K UE-specific reference signal position on the m layer

wherein, the quantity that K is UE-specific reference signal subcarrier, the number of plies that M is the stack of UE-specific reference signal position.

3. channel estimation methods as claimed in claim 1, is characterized in that, carries out frequency domain interpolation and specifically comprise: by autocorrelation matrix

be divided into a series of sub-block autocorrelation matrixes, then each sub-block autocorrelation matrix is averaged

according to formula: ${\hat{H}}_{\mathrm{LMMSE},n}={\stackrel{\&OverBar;}{R}}_{{\mathrm{HH}}_p}^{\left(L\right)}{({\stackrel{\&OverBar;}{R}}_{H_p{H}_p}^{\left(L\right)}+I_p^{\left(L\right)}\frac{\mathrm{\&beta;}}{\mathrm{SNR}})}^{-1}{\hat{H}}_{\mathrm{LS},n}$ Obtain the channel frequency response of n all subcarriers of sub-block; Integrate the channel frequency response value of each sub-block subcarrier, according to formula:

obtain the channel frequency response of all subcarriers on the OFDM symbol of UE-specific reference signal place, wherein,

mean the cross-correlation matrix after the interior all subcarriers of each sub-block and UE-specific reference signal position subcarrier are averaged, β is constant, and SNR is average signal-to-noise ratio,

for unit matrix,

it is the channel frequency response of n sub-block UE-specific reference signal position.

4. channel estimation methods as claimed in claim 1, it is characterized in that, for the OFDM symbol that does not have the UE-specific reference signal to distribute, by copying the channel frequency response of subcarrier on the OFDM symbol of UE-specific reference signal place, obtain the channel frequency response on other OFDM symbol.

5. channel estimation methods as claimed in claim 2, is characterized in that, for local frequency domain UE-specific reference signal

with the actual frequency domain UE-specific reference signal r received ^(k)=[r ^{(6, k)}, r ^{(7, k)}, r ^{(13, k)}, r ^{(14, k)}], according to formula:

${\hat{H}}_{\mathrm{LS},m}^{\left(k\right)}=\frac{r^{(6,k)}{\left(s_m^{(6,k)}\right)}^H+r^{(7,k)}{\left(s_m^{(7,k)}\right)}^H+r^{(13,k)}{\left(s_m^{(13,k)}\right)}^H+r^{(14,k)}{\left(s_m^{(14,k)}\right)}^H}{s_m^{(6,k)}{\left(s_m^{(6,k)}\right)}^H+s_m^{(7,k)}{\left(s_m^{(7,k)}\right)}^H+s_m^{(13,k)}{\left(s_m^{(13,k)}\right)}^H+s_m^{(14,k)}{\left(s_m^{(14,k)}\right)}^H}$ Obtain the LS estimation of the upper reference signal of m straton carrier wave k position, wherein,

mean the local reference signal on m straton carrier wave k, r ^{(l, k)}mean the receiving symbol of the upper reference signal of receiving terminal subcarrier k position, l means the position of reference signal place OFDM symbol, l ∈ { 6,7,13,14}.

6. channel estimation methods as claimed in claim 3, is characterized in that, channel matrix H is divided into to the sub-vector that M length is L, according to formula: B _c/ Δ _f≈ L determines length L, wherein, and Δ _ffor the width of subcarrier, according to the root mean square τ of channel delay _rmscall formula and determine correlation bandwidth:

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