CN101986589B - Method and device for decoding LTE (long term evolution) downlink precoding - Google Patents

Abstract

The invention discloses a method for decoding LTE (long term evolution) downlink precoding. The method comprises the following steps: determining a precoding matrix and the number of input layers according to system information; selecting a sub-square matrix corresponding to the subsets in the determined precoding matrix through selecting a plurality of subsets in the input vectors of decoders, wherein the number of dimensions of each subset is equal to the number of input layers; carrying out matrix inversion on the sub-square matrix to obtain the output of the decoders at each layer; and carrying out averaging or weighted averaging or adding on the output of the decoders at each layer, which is estimated by all subsets, so as to obtain the output of the decoders to further obtain the input of precoding. In the method, the output of the decoders at each layer can be solved according to selected different subsets to further solve the output of the decoders, which can fully utilizes the principle of against frequency-selective fading of an MIMO (multiple input multiple output) system. According to the method, decoding is realized and the accuracy and robustness of decoding can be improved simultaneously. The invention also discloses a device for decoding LTE downlink precoding when an LTE downlink is at a specific multi-antenna port.

Description

Method and device that the LTE downlink precoding is decoded

Technical field

The present invention relates to LTE (Long Term Evolution) system, be specifically related under the multi-antenna multiplexed background of LTE system down link, be used for the method for decoding without the precoding of the spatial reuse of cyclic delay diversity (CCD) and long delay cyclic delay diversity.

Background technology

The Long Term Evolution of the 3rd Generation Mobile Communication System (LTE) project is to move project partner (3GPP) tissue the 3rd generation to propose 3G to the wideband wireless mobile communication system scheme of the 4th third-generation mobile communication (4G) system transition, its down link has adopted OFDM (OFDM) and MIMO (multiple-input and multiple-output) technology, be used for anti-frequency-selective channel decline, improve power system capacity.

Fig. 1 is the transmitter physical layer process theory diagram of the LTE down link that provides according to ETSI TS 136.211 v8.5.0 versions.As shown in Figure 1, the code word of input is carried out that scrambling is processed, modulation map unit 112 is carried out the baseband modulation mapping, after a layer map unit 113 carry out layer mapping, is inputted precoder 114 and encode through scrambler 111 successively.Code word behind precoder 114 coding carries out sending to each transmitting antenna by antenna opening after resource mapping, OFDM modulating unit 116 carry out the OFDM modulation through resource mapping unit 115 successively.The precoding input number of plies can be 1 to 4 layer.

In the MIMO of LTE down link technology, for the precoder 114 among Fig. 1, ETSITS 136.211 v8.5.0 versions have stipulated that two class technical schemes carry out precoding, one is based on the emission diversity scheme of 2 antenna opening and 4 antenna opening, two are based on without the spatial multiplex scheme of cyclic delay diversity and the spatial multiplex scheme of long delay cyclic delay diversity, and the present invention relates generally to the second technical scheme.

For the spatial multiplex scheme without cyclic delay diversity, its coding formula is:

$\left[\begin{array}{c}{y}^{\left(0\right)}\left(i\right)\\ M\\ y^{(P-1)}\left(i\right)\end{array}\right]=W\left(i\right)\left[\begin{array}{c}{x}^{\left(0\right)}\left(i\right)\\ M\\ x^{(\mathrm{\υ}-1)}\left(i\right)\end{array}\right]---\left(1\right)$

Wherein, x (i)=[x ⁽⁰⁾(i) Λ x ^(v-1)(i)] ^TBe i and process the constantly input vector of precoder, y (i)=[y ⁽⁰⁾(i) K y ^(P-1)(i)] ^TBe i and process the constantly output vector of precoder, W (i) is encoder matrix, and size is P * υ, and p is the antenna opening number, and v is the input number of plies.For 4 antenna opening, namely { system of 0,1,2,3}, the table 6.3.4.2.3-2 of ETSI TS 136.211v8.5.0 version is seen in the definition of W (i) to mouth.

For the spatial multiplex scheme of long delay cyclic delay diversity, its coding formula is:

$\left[\begin{array}{c}{y}^{\left(0\right)}\left(i\right)\\ M\\ y^{(P-1)}\left(i\right)\end{array}\right]=W\left(i\right)D\left(i\right)U\left[\begin{array}{c}{x}^{\left(0\right)}\left(i\right)\\ M\\ x^{(\mathrm{\υ}-1)}\left(i\right)\end{array}\right]---\left(2\right)$

Wherein, x (i), y (i) are identical with formula (1) with W (i), and the definition of matrix D (i) and U is referring to the 6.3.4.2 part of ETSI TS 136.211 v8.5.0.

Fig. 2 is the launch scenario corresponding to Fig. 1, at the physical layer process theory diagram of the receiver of portable terminal.As shown in Figure 2, reception antenna receives carry out OFDM demodulation, resource reflection and penetrate unit 122 and carry out the resource reflection and penetrate by OFDM demodulating unit 121 successively by the code word of the transmission antennas transmit of transmitter after, input decoder 123 is decoded, namely for the precoding of transmitter precoder 114, the inverse process of perfect (1) and formula (2).Decoder 123 decoded code words are penetrated that the reflection of carrying out layer mapping in unit 124 is penetrated, behind the descrambling of the counter modulation mapping of counter modulation map unit 125, descrambler 126, are sent by antenna opening through reflection successively.

For the decoding of adopting the emission of 4 antenna opening, the precoding input number of plies is 1 or 4 situation, and the decoder decode procedure is fairly simple, and the present invention does not relate to this.When the present invention is 2 layers or 3 layers mainly for 4 antenna opening, the precoding input number of plies, the decoding of precoder 114 precodings of 123 pairs of transmitters of decoder of receiver.

The theoretical construct of decoder 123 as shown in Figure 3 among Fig. 2.Such as Fig. 3, the input y (i) of decoder 123 ideally is that precoder 114 is by the output of formula (1) or formula (2) coding among Fig. 1, and y (i) is 14 * 1 vector.The output z (i) of decoder 123 the precoding input number of plies be 2 and the number of plies be 3 o'clock, be respectively 2 * 1 and 3 * 1 vector, its decoding matrix W _D(i) should be respectively in theory 2 * 4 and 3 * 4 matrix, to satisfy z (i)=W _D(i) solving equation of y (i).

Can find out that from the table 6.3.4.2.3-2 of ETSI TS 136.211 v8.5.0 versions when the precoding input number of plies was 2 and 3, the pre-coding matrix W (i) of precoder 114 was respectively 4 * 2 and 4 * 3 matrix.Because this matrix is not square formation, therefore can not directly utilize the inverse matrix of the middle W (i) of formula (1) and formula (2) to find the solution the decoding matrix W of decoder 123 _D(i), thus the inverse matrix that receiver can not be by pre-coding matrix W (i) to transmitter precoding decode.

Therefore, be necessary to provide a kind of receiver method that precoding is decoded to transmitter and device.

Summary of the invention

The purpose of this invention is to provide a kind of method and device that the LTE downlink precoding is decoded, can decode to the LTE downlink precoding.

To achieve these goals, the invention provides a kind of method that the LTE downlink precoding is decoded, may further comprise the steps:

Finish OFDM in the data that reception antenna receives and separate and be in harmonious proportion after the resource reflection penetrates, estimate that by the demodulated reference signal that the transmitter physical layer is inserted each transmitting antenna mouth is to the channel of each reception antenna;

According to the channel of estimating the data that OFDM separates after the reflection of mediation resource is penetrated are carried out channel equalization, estimate the input vector of decoder;

The system information that arranges during according to the configure transmitter physical layer is determined the pre-coding matrix that precoder selects, the input number of plies and the transmitting antenna mouth number of precoder;

When the transmitting antenna mouth is 4, when the input number of plies is 2 or 3, select a plurality of shortening vectors in the decoder input vector, each element number that shortens vector with input the number of plies and equate;

Each is shortened vector, shorten the position of element in the decoder input vector of vector according to this, in pre-coding matrix, select the vector of correspondence position to consist of a sub-square formation;

Each is shortened vector, and its sub-square formation is inverted obtains corresponding decoding matrix, calculates corresponding decoding output according to decoding matrix;

All decoding outputs of shortening vectors are averaging or ask weighted average or summation, obtain the output of decoder, according to the input of the output estimation precoding of decoder.

In one embodiment of the invention, the selection of described shortening vector is specially:

When the input and output of pre-coding matrix adopt row vector to represent, select row vector element in the decoder input vector that row vector represents by the input layer number sieve, the row vector element that filters out consists of and shortens vector,

Then, the selection of described sub-square formation is specially:

In pre-coding matrix, select with decoder input vector that row vector represents in consist of the sub-square formation of row formation corresponding to the element that shortens vector,

Then, described output according to decoding corresponding to decoding matrix calculating is specially:

For each shortening vector that is consisted of by the row vector element that filters out, calculate the decoding output of correspondence by the transposition computing according to the decoding matrix of correspondence.

In another embodiment of the present invention, the selection of described shortening vector is specially:

When the input and output of pre-coding matrix adopt column vector to represent, select column vector element in the decoder input vector that column vector represents by the input layer number sieve, the column vector element that filters out consists of and shortens vector,

Then, the selection of described sub-square formation is specially:

In pre-coding matrix, select with decoder input vector that column vector represents in consist of row corresponding to the element of shortening vector and consist of sub-square formation,

Then, described output according to decoding corresponding to decoding matrix calculating is specially:

For each shortening vector that is consisted of by the column vector element that filters out, calculate the decoding output of correspondence by the transposition computing according to the decoding matrix of correspondence.

In an again embodiment of the present invention, the step that the input of precoding is calculated in described output according to decoder is specially:

For the decoding without the cyclic delay diversity precoding, the estimation of its encoder input vector is defined as decoder output;

To the decoding of long time delay cyclic delay diversity precoding, the pass of the estimation of its encoder input vector and decoder output is:

Wherein z (i) is decoder output,

Be the estimation of encoder input vector, make Ω=D (i) U, use

Finish decoding.

The present invention also provides a kind of device that the LTE downlink precoding is decoded, and comprising:

Channel estimating unit is used for finishing OFDM in the data that reception antenna receives and separates and be in harmonious proportion after the resource reflection penetrates, and estimates that by the demodulated reference signal that the transmitter physical layer is inserted each transmitting antenna mouth is to the channel of each reception antenna;

Decoder input vector estimation unit, the channel that is used for estimating according to channel estimating unit carries out channel equalization to the data that OFDM separates after the reflection of mediation resource is penetrated, and estimates the input vector of decoder;

Precoder information determining unit, the system information that arranges when being used for according to the configure transmitter physical layer is determined the input number of plies and the transmitting antenna mouth number of the selected pre-coding matrix of precoder, precoder;

Shorten the vector selected cell, be used for when the transmitting antenna mouth be 4, when inputting the number of plies and being 2 or 3, select a plurality of shortening vectors in the decoder input vector that decoder input vector estimation unit is estimated, each element number that shortens vector equates with the input number of plies that precoder information determining unit is determined;

A plurality of square formation construction units, each square formation construction unit is used for the position of the decoder input vector estimated at decoder input vector estimation unit according to each element of the shortening vector that shortens the correspondence that the vector selected cell selects, selects the vector of correspondence position to consist of a sub-square formation in the pre-coding matrix that precoder information determining unit is determined;

A plurality of decodings output computing units, each decoding output computing unit are used for the sub-square formation that corresponding square formation construction unit makes up inverted and obtain corresponding decoding matrix, and the decoding of answering of getting it right is exported according to decoding matrix and corresponding shortening vector meter;

Decoder is always exported determining unit, is used for the decoding output that all decoding output computing units calculate is averaging or asks weighted average or summation, obtains the output of decoder, determines the input of precoding according to the output of decoder.

Compared with prior art, the method that the present invention decodes to the LTE downlink precoding and device are not to find the solution decoding matrix W when the decoding that realizes precoding _D(i), but determine pre-coding matrix and the input number of plies according to system information, by in the input vector of decoder, selecting a plurality of subsets, the dimension of every subset equates with the input number of plies of determining, in the pre-coding matrix of determining, select the sub-square formation corresponding with subset, the antithetical phrase square formation is carried out square formation and is inverted, obtain the output of each layer decoder, the output of each layer decoder of again all subsets being estimated averages or weighted average or addition, obtain the output of high-precision decoder, and then obtain the input of high-precision precoding.That is to say that this method and device can successfully be realized the LTE downlink precoding is decoded.

In addition, when subsetting, the input vector element system of selection of multiple decoder, the output of each layer decoder of finding the solution for different selections averages or weighted average or addition can take full advantage of the principle of the anti-frequency selective fading of mimo system, therefore this method and device can improve precision and the robustness of decoding when realizing decoding.

By following description also by reference to the accompanying drawings, it is more clear that the present invention will become, and these accompanying drawings are used for explaining embodiments of the invention.

Description of drawings

Fig. 1 is the transmitter physical layer process theory diagram of existing LTE down link.

Fig. 2 is the receiver physical layer process theory diagram of existing LTE down link.

Fig. 3 is the theoretical principle figure of decoder in the processing procedure of receiver physical layer of LTE down link shown in Figure 2.

The flow chart of Fig. 4 method that to be the present invention decode to multi-antenna multiplexed LTE downlink precoding.

The structured flowchart of Fig. 5 device that to be the present invention decode to multi-antenna multiplexed LTE downlink precoding.

Embodiment

With reference now to accompanying drawing, describe the embodiments of the invention journey, similar element numbers represents software or the hardware cell of similar software algorithm module or software algorithm in the accompanying drawing.

Method and device that the present invention decodes to the LTE downlink precoding mainly are the space multiplexing pre-coding matrixes that provides in the ETSI TS 136.211v8.5.0 version, a kind of scheme in 4 transmitting antenna ports to 2 layer precoding input layer or 3 layers of precoding input layer decoding output that proposes, be used for without the spatial reuse decoding of cyclic delay diversity and the spatial reuse decoding of long delay cyclic delay diversity, finish the inverse process of precoder 114 among Fig. 1, i.e. the realization of decoding of decoder 123 among Fig. 2.The below is elaborated respectively to method and the device that the present invention decodes to the LTE downlink precoding.

As shown in Figure 4, the present invention's method that the LTE downlink precoding is decoded may further comprise the steps:

Step S1, i that reception antenna receives constantly data finish OFDM and separate and be in harmonious proportion after the resource reflection penetrates, estimate that by the demodulated reference signal that the transmitter physical layer is inserted each transmitting antenna mouth is to the channel of each reception antenna;

Step S2 carries out channel equalization according to the channel of estimating to the i moment data that OFDM separates after the reflection of mediation resource is penetrated, and estimates the input vector of decoder

(estimating the output of precoder);

Step S3, the table 6.3.4.2.3-2 of the system information that arranges during according to the configure transmitter physical layer and ETSI TS 136.211 v8.5.0 versions determine input number of plies v and the transmitting antenna mouth number p of the selected pre-coding matrix W (i) of transmitter precoder, precoder;

Step S4, when transmitting antenna mouth p is 4, when input number of plies v is 2 or 3, at the input vector of decoder

The a plurality of subsets of middle selection, the element number of every subset equates that with input number of plies v every subset consists of the shortening vector of 2 elements or 3 elements

Wherein k represents the selection of k kind;

Step S5 shortens vector to each

Shorten vector according to this

Element at the input vector of decoder

In the position, in pre-coding matrix W (i), select the vector of correspondence position to consist of a sub-square formation

Step S6 shortens vector to each

To its sub-square formation

Invert and obtain corresponding decoding matrix

Again according to the decoding matrix that obtains

Calculate corresponding decoding output z ^k(i).

Step S7 shortens vector to all Decoding output z ^k(i) be averaging or ask weighted average or summation, the output z (i) of acquisition decoder (computing formula that is averaging is:

Ask average weighted computing formula to be:

G wherein ^k(i) be i and process the weighted volumes that constantly k bar decoding branch road (corresponding k kind is selected) obtains by channel estimating; The computing formula of summation is: Input according to the output estimation precoding of decoder.

As shown from the above technical solution, this method is not to find the solution decoding matrix W when the decoding that realizes precoding _D(i), but determine pre-coding matrix W (i) and input number of plies v according to system information, by the input vector at decoder

The a plurality of subsets of middle selection

Every subset

Dimension equate selection and subset in the pre-coding matrix W (i) that determines with the input number of plies v that determines

Corresponding sub-square formation

The antithetical phrase square formation

Carry out square formation and invert, obtain the output z of each layer decoder ^kThe output z of each layer decoder of (i), again all subsets being estimated ^k(i) average or weighted average or addition, obtain the output of high-precision decoder, and then obtain the input of high-precision precoding.

Because the present invention is at subsetting y _sThe input vector that multiple decoder is arranged in the time of (i) The element system of selection, the output z of each layer decoder of finding the solution for different selections ^k(i) average or weighted average or addition can take full advantage of the principle of the anti-frequency selective fading of mimo system, improved estimated accuracy, strengthened the robustness of estimating.

Need to prove, the data that reception antenna receives among the step S1 are after the data of transmitter physical layer antenna opening output are processed through the transmitter radio frequency unit, process transmission antennas transmit, wireless channel are propagated again, reception antenna receives and finish carrier wave demodulation, the data after the analog-to-digital conversion by receiver.

As a kind of preferred mode, shorten vector among the described step S4 Selection be specially:

When the precoding formula is column vector when representing, suc as formula (3a) with (4a), the input vector of the decoder that column vector is represented

In column vector carry out the screening of element by input number of plies v, namely select arbitrarily the input vector that column vector represents

P column element in v value, consist of to shorten vector

Then, described step S5 neutron square formation

Selection be specially:

In pre-coding matrix W (i), select and input vector

Middle formation

Row corresponding to element consist of sub-square formation

Namely at input vector

In selected which row to consist of to shorten vector Just in pre-coding matrix W (i), select too which row to consist of sub-square formation

As another kind of preferred mode, shorten vector among the described step S4

Selection be specially:

When the precoding formula is row vector when representing, suc as formula (3b) with (4b), the input vector of the decoder that row vector is represented by input number of plies v

Row vector carry out the screening of element, namely select arbitrarily the input vector that row vector represents

P row element in v value, consist of to shorten vector

Then, described step S5 neutron square formation Selection be specially:

In pre-coding matrix W (i), select and input vector

Middle formation

Row corresponding to element consist of sub-square formation

Namely at input vector

Which row of middle selection consist of is shortened row vector

Just in pre-coding matrix W (i), select too which row to consist of sub-square formation

Without cyclic delay diversity

The precoding formula that column vector represents is: [y ⁽⁰⁾(i) Λ y ^(P-1)(i)] ^T=W (i) [x ⁽⁰⁾(i) Λ x ^[v-1)(i)] ^T(3a)

The precoding formula that row vector represents is: [y ⁽⁰⁾(i) Λ y ^(P-1)(i)]=[x ⁽⁰⁾(i) Λ x ^[v-1)(i)] W ^T(i) (3b) long delay cyclic delay diversity

The precoding formula that column vector represents is: [y ⁽⁰⁾(i) Λ y ^(P-1)(i)] ^T=W (i) DU[x ⁽⁰⁾(i) Λ x ^[v-1)(i)] ^T(4a)

The precoding formula that row vector represents is: [y ⁽⁰⁾(i) Λ y ^(P-1)(i)]=[x ⁽⁰⁾(i) Λ x ^[v-1)(i)] U ^TD ^TW ^T(i) (4b)

Wherein, the expression of the subscript " T " among formula (3a), (3b), (4a), (4b) transposition computing.

The decoding matrix that basis obtains among the step S6

Calculate corresponding decoding output z ^k(i) be specially:

Screen the shortening vector that obtains for each based on row vector or column vector

Decoding matrix according to correspondence

Decipher, obtain corresponding decoding output z ^k(i).

The precoding formula that column vector is represented, such as formula (3a) and (4a), its decoding formula is:

$z^k\left(i\right)=W_{D,s}^k\left(i\right)y_s^k\left(i\right)---\left(5a\right)$

The precoding formula that row vector is represented, such as formula (3b) and (4b), its decoding formula is:

${\left[z^k\left(i\right)\right]}^T={\left[y_s^k\left(i\right)\right]}^T{\left[W_{D,s}^k\left(i\right)\right]}^T---\left(5b\right)$

Wherein, the expression of the subscript " T " among formula (5a), (5b) transposition computing.

The step of calculating the input of precoding according to the output of decoder among the step S7 is specially:

For the decoding without the cyclic delay diversity precoding, its encoder input vector x (i) is estimated as the decoder output z (i) that step S7 obtains; To the decoding of long time delay cyclic delay diversity precoding, the pass of the output z (i) that the estimation of its encoder input vector x (i) and step S7 obtain is:

Wherein,

Be the decoding output vector of long time delay cyclic delay diversity precoding, or perhaps its encoder input vector is in the estimation of receiver.The definition of matrix D (i) and U is referring to the 6.3.4.2 part of ETSI TS 136.211 v8.5.0.Make Ω=D (i) U, use Finish decoding, wherein subscript " 1 " expression matrix is inverted.

It should be noted that, although this method is in the LTE down link, the input number is 2 or 3, the output number is the decoding of the precoder of 4 (the output number is greater than the input numbers), in every case be in system, when adopting the output number greater than the decoding of the encoder matrix W (i) of input number, utilize the coding input number that obtains to carry out the sub-square formation screening of encoder matrix, recycle sub-encoder matrix invert decode after, and then it is all inconsistent with the present invention to be averaging or to ask weighted average or summation to improve the method for estimated performance.

As shown in Figure 5, the present invention's device that the LTE downlink precoding is decoded comprises:

Channel estimating unit 210, be used for i that reception antenna receives constantly data finish OFDM and separate and be in harmonious proportion after the resource reflection penetrates, estimate that by the demodulated reference signal that the transmitter physical layer is inserted each transmitting antenna mouth is to the channel of each reception antenna;

Decoder input vector estimation unit 220 carries out channel equalization for the channel of estimating according to channel estimating unit 210 to the i moment data that OFDM separates after the reflection of mediation resource is penetrated, and estimates the input vector of decoder

The input vector of described decoder

It is the estimation to precoder output vector y (i);

Precoder information determining unit 230, the system information that arranges when being used for according to the configure transmitter physical layer and the table 6.3.4.2.3-2 of ETSI TS136.211 v8.5.0 version determine input number of plies v and the transmitting antenna mouth number p of the selected pre-coding matrix W (i) of transmitter precoder, precoder;

Shorten vector selected cell 240, be used for when transmitting antenna mouth p be 4, when input number of plies v is 2 or 3, at the decoder input vector of decoder input vector estimation unit 220 estimations The a plurality of subsets of middle selection, the element number of every subset equates that with the input number of plies v that precoder information determining unit is determined every subset consists of the shortening vector of 2 elements or 3 elements

Wherein k represents the selection of k kind;

A plurality of square formation construction units 250, each square formation construction unit 250 is used for the shortening vector according to the correspondence that shortens 240 selections of vector selected cell

The decoder input vector estimated at decoder input vector estimation unit 220 of each element

In the position, in the pre-coding matrix W (i) that precoder information determining unit 230 is determined, select sub-square formation of vector formation of correspondence position

A plurality of decoding output computing units 260, the sub-square formation that each decoding output computing unit 260 is used for corresponding square formation construction unit 250 structures

Invert and obtain corresponding decoding matrix

(Inversion Formula is:

), according to the decoding matrix that obtains

With corresponding shortening vector

Calculate corresponding decoding output z ^k(i) (computing formula is:

Decoder is always exported determining unit 270, is used for the decoding output z that all decoding output computing units 260 are calculated ^k(i) be averaging or ask weighted average or summation, the output z (i) of acquisition decoder (computing formula that is averaging is: Ask average weighted computing formula to be

G wherein ^k(i) be i and process the weighted volumes that constantly k bar decoding branch road (corresponding k kind is selected) obtains by channel estimating; The computing formula of summation is ), determine the input of precoding according to the output of decoder.

Above invention has been described in conjunction with most preferred embodiment, but the present invention is not limited to the embodiment of above announcement, and should contain various modification, the equivalent combinations of carrying out according to essence of the present invention of lid.

Claims (4)

1. method that the LTE downlink precoding is decoded may further comprise the steps:

I that reception antenna receives constantly data finish OFDM and separate and be in harmonious proportion after the resource reflection penetrates, estimate that by the demodulated reference signal that the transmitter physical layer is inserted each transmitting antenna mouth is to the channel of each reception antenna;

According to the channel of estimating the i moment data that OFDM separates after the reflection of mediation resource is penetrated are carried out channel equalization, estimate the input vector of decoder;

The system information that arranges during according to the configure transmitter physical layer is determined the pre-coding matrix that precoder selects, the input number of plies and the transmitting antenna mouth number of precoder;

When the transmitting antenna mouth is 4, when the input number of plies is 2 or 3, select a plurality of subsets in the input vector of decoder, the element number of every subset equates with the input number of plies, the shortening vector of every 2 elements of subset formation or 3 elements;

Each is shortened vector, shorten the position of element in the decoder input vector of vector according to this, in pre-coding matrix, select the vector of correspondence position to consist of a sub-square formation;

Each is shortened vector, and its sub-square formation is inverted obtains corresponding decoding matrix, calculates corresponding decoding output according to decoding matrix;

All decoding outputs of shortening vectors are averaging or ask weighted average or summation, obtain the output of decoder, according to the input of the output estimation precoding of decoder.

2. the method that the LTE downlink precoding is decoded as claimed in claim 1 is characterized in that, the selection of described shortening vector is specially:

When the input and output of pre-coding matrix adopt row vector to represent, select row vector element in the decoder input vector that row vector represents by the input layer number sieve, the row vector element that filters out consists of and shortens vector,

Then, the selection of described sub-square formation is specially:

In pre-coding matrix, select with decoder input vector that row vector represents in consist of the sub-square formation of row formation corresponding to the element that shortens vector,

Then, described output according to decoding corresponding to decoding matrix calculating is specially:

For each shortening vector that is consisted of by the row vector element that filters out, calculate the decoding output of correspondence by the transposition computing according to the decoding matrix of correspondence.

3. the method that the LTE downlink precoding is decoded as claimed in claim 1 is characterized in that, the selection of described shortening vector is specially:

When the input and output of pre-coding matrix adopt column vector to represent, select column vector element in the decoder input vector that column vector represents by the input layer number sieve, the column vector element that filters out consists of and shortens vector,

Then, the selection of described sub-square formation is specially:

In pre-coding matrix, select with decoder input vector that column vector represents in consist of row corresponding to the element of shortening vector and consist of sub-square formation,

Then, described output according to decoding corresponding to decoding matrix calculating is specially:

For each shortening vector that is consisted of by the column vector element that filters out, calculate the decoding output of correspondence by the transposition computing according to the decoding matrix of correspondence.

4. device that the LTE downlink precoding is decoded comprises:

Channel estimating unit is used for finishing OFDM in the data that reception antenna receives and separates and be in harmonious proportion after the resource reflection penetrates, and estimates that by the demodulated reference signal that the transmitter physical layer is inserted each transmitting antenna mouth is to the channel of each reception antenna;

Decoder input vector estimation unit, the channel that is used for estimating according to channel estimating unit carries out channel equalization to the data that OFDM separates after the reflection of mediation resource is penetrated, and estimates the input vector of decoder;

Precoder information determining unit, the system information that arranges when being used for according to the configure transmitter physical layer is determined the input number of plies and the transmitting antenna mouth number of the selected pre-coding matrix of precoder, precoder;

Shorten the vector selected cell, be used for when the transmitting antenna mouth be 4, when inputting the number of plies and being 2 or 3, in the input vector of decoder, select a plurality of subsets, the element number of every subset equates with the input number of plies, every subset consists of the shortening vector of 2 elements or 3 elements, select a plurality of shortening vectors in the decoder input vector that decoder input vector estimation unit is estimated, each element number that shortens vector equates with the input number of plies that precoder information determining unit is determined;

A plurality of square formation construction units, each square formation construction unit is used for the position of the decoder input vector estimated at decoder input vector estimation unit according to each element of the shortening vector that shortens the correspondence that the vector selected cell selects, selects the vector of correspondence position to consist of a sub-square formation in the pre-coding matrix that precoder information determining unit is determined;

A plurality of decodings output computing units, each decoding output computing unit are used for the sub-square formation that corresponding square formation construction unit makes up inverted and obtain corresponding decoding matrix, and the decoding of answering of getting it right is exported according to decoding matrix and corresponding shortening vector meter;

Decoder is always exported determining unit, is used for the decoding output that all decoding output computing units calculate is averaging or asks weighted average or summation, obtains the output of decoder, determines the input of precoding according to the output of decoder.

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