CN102195758A - Multi-user precoding method and system, transmitter and receiver - Google Patents

Abstract

The invention provides a multi-user precoding method and a system, a transmitter and a receiver. The method comprises the following steps: presetting a codebook set including codebooks with normalized amplitude; normalizing the amplitude component of channel information after the receiver estimates the channel information from the transmitter to the receiver, and selecting a codebook most similar to the normalized channel information from the codebook set as the quantized channel information; and acquiring the quantized channel information of a plurality of receivers, and precoding the downlink data of the plurality of receivers based on the quantized channel information by using the transmitter. The scheme in the invention can effectively enlarge the capacity of a multi-user system.

Description

Method for multi-user pre-coding and system, transmitter and receiver

Technical field

The present invention relates to multi-user (MU) precoding, relate in particular to method for multi-user pre-coding and system, transmitter and receiver.

Background technology

Transmission was achieved when the development of multi-antenna technology made a plurality of user.The MU system has many advantages, and for example: can improve power system capacity by a plurality of user profile of transmission on same resource block, multi-user's scheduling provides multi-user diversity, or the like.For the signal identical time, frequency and a plurality of users of sign indicating number territory transmitted over resources, and reduce the multi-user and disturb (Co-channel Interference) in the road altogether, precoding technique is introduced into and has become one of key technology in the MU system.

In precoding technique based on code book, base station and travelling carriage all can be known the code book set that content preset is fixing, as the travelling carriage of receiver channel information according to self, according to the criterion that sets in advance, channel information is quantified as a code book in the code book set, and with this code book corresponding transmitter that is indexed in code book set, transmitter obtains quantized channel information according to institute's feedack, according to quantized channel information downstream signal is carried out pre-encode operation.

In order to obtain bigger channel capacity, become one of research focus based on the nonlinear precoding of code book.(Tomlinson-Harashima Precoding, THP) precoding technique is a kind of nonlinear precoding technology comparatively commonly used to have the uncommon agate of Tomlinson-Harrar of Limited Feedback.This precoding technique is used for single input and output originally, and (Single Input Single Output, SISO) system carries out equilibrium to the channel that has intersymbol interference, is used for carrying out in the MU system elimination of multi-user interference now.

Fig. 1 shows existing THP method for precoding flow chart with Limited Feedback.Referring to Fig. 1, this method comprises:

In step 101, generation in advance comprises channel quality information, and (Channel Quality Information, CQI) (Channel Direction Information is CDI) in interior code book set with the channel directional information.

Comprise a plurality of code books that transmitting antenna and number of bits of feedback according to the MU system are provided with in the set of code book in this step, all comprise inseparable CQI and CDI in each code book.

In step 102, each receiver is the channel quantitative of self, determines corresponding code book in the code book set, and with determined code book feedback information to transmitter.

Each receiver is when quantizing channel, at first determine the channel matrix H of himself, again relatively with each code book in this channel matrix H and the code book set, find code book with the mould minimum of the direct vector differential mode of channel matrix H, this code book is this receiver corresponding code book in the code book set, in other words, this receiver with the channel quantitative of self to aforementioned code book.In other words, suppose that the code book in the code book set is C _i, 1≤i≤2 ^N, wherein N is a number of bits of feedback, then the code book of receiver correspondence satisfies $C_i=\arg \underset{i={1~2}^N}{\min }\left|\right|H-C_i\left|\right|.$

Behind the code book of having determined receiver correspondence in the code book set, receiver can report transmitter by up channel with the index of this code book in the code book set, so that after this transmitter utilizes this code book that the multiuser downstream data are carried out pre-encode operation.

In step 103, transmitter carries out precoding processing according to the code book information and the code book set of receiver feedback to signal to be sent.

Because transmitter is known the set of the used code book of receiver in advance, therefore, search the code book of the code book index correspondence that receiver reports here in the code book set.Then, the multiuser channel that transmitter is formed a plurality of receiver code books carries out RQ and decomposes, and obtains unitary matrice Q and triangle battle array R.After this, transmitter utilizes aforesaid matrix Q and R, and transmitter is carried out pre-encode operation to the downlink data of receiver transmission.

So far, finish existing THP precoding flow process with Limited Feedback.

From the above description as seen, have in the THP precoding process of Limited Feedback existing, all comprise not separated CQI and CDI in each code book, like this, receiver is when carrying out channel quantitative, selected code book might differ bigger with the channel of reality, thereby CQI is less, signal interference ratio is also less.The principle that increases according to power system capacity with along with the increase of signal interference ratio so, under the less situation of signal interference ratio, power system capacity and less, so systematic function is relatively poor.

Summary of the invention

The invention provides a kind of method for multi-user pre-coding, can improve the MU systematic function.

In method for multi-user pre-coding of the present invention, comprising:

Set in advance the code book set of the code book that comprises amplitude normalization;

Receiver carries out normalization to the range weight of described channel information behind the channel information that estimates from transmitter to this receiver, from described code book set, select again with normalization after the immediate code book of channel information as quantized channel information;

Transmitter obtains the quantized channel information of a plurality of receivers, and the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information.

Wherein, the described code book set that sets in advance the code book that comprises amplitude normalization is:

Be provided with that line number equals number of transmit antennas, columns equals 2 ^NCode book set, wherein N is a number of bits of feedback, and the mould of the code book of described amplitude normalization is 1.

Preferably, described transmitter obtains before the quantized channel information of a plurality of receivers, further comprises: receiver reports transmitter with described quantized channel information index.

Wherein, described from the set of described code book, select with normalization after the immediate code book of channel information as quantized channel information be:

From the set of described code book, select and normalization after channel information between the code book of vector differential mode minimum, and with this code book as described quantized channel information.

Wherein, described transmitter obtains the quantized channel information of a plurality of receivers and is:

The quantized channel information index that transmitter reports according to receiver reads and the corresponding code book of this index from the set of described code book, with the code book that the reads quantized channel information as this receiver.

Wherein, described downlink data to described a plurality of receivers carry out based on the pre-encode operation of described quantized channel information be:

The channel matrix that transmitter is formed the quantized channel information of described a plurality of receivers carries out RQ and decomposes, and calculates the intermediary matrix of pre-encode operation;

Utilize result that RQ decomposes and intermediary matrix that the downlink data of described a plurality of receivers is carried out pre-encode operation.

Wherein, described receiver reports described quantized channel information index after the transmitter, further comprises:

Transmitter obtains the channel quality information of described a plurality of receivers, and according to described channel quality information calculate the signal interference ratio of each receiver and capacity and.

Wherein, described transmitter obtains the channel quality information of described a plurality of receivers and is: transmitter is from self obtaining the channel quality information of described receiver.

Preferably, described receiver reports described quantized channel information index before the transmitter, further comprises: receiver after according to normalization channel information and the quantization error between the described quantized channel information calculate the channel quality information of self;

Described transmitter obtains before the channel quality information of described a plurality of receivers, further comprises: receiver reports transmitter with the channel quality information of self;

The channel quality information that described transmitter obtains described a plurality of receivers is: receive the channel quality information that comes from receiver.

Wherein, channel information and quantization error described quantized channel information between the channel quality information that calculate self of described receiver after according to normalization is:

According to formula

Calculate described quantization error, wherein Δ _iBe quantization error,

Be channel information h _iResult after the normalization, h _iBe the channel information of receiver i, Be quantized channel information;

According to formula

Calculating channel quality information, wherein CQI _iBe the channel quality information of receiver i, P ₀Be transmitting power, N ₀Be the noise power of receiver, K is a number of transmit antennas, h _iChannel information for receiver i.

Wherein, the signal interference ratio of described each receiver of calculating is:

According to formula S INR _i=R _IiCQI _iCalculate signal interference ratio, wherein, SINR _iBe the signal interference ratio of receiver i, R _IiFor quantized channel information being carried out the diagonal entry of the triangular matrix R that RQ obtains in decomposing, CQI _iChannel quality information for receiver i.

The present invention also provides a kind of multi-user pre-coding system, can improve the MU systematic function.

In multi-user pre-coding system of the present invention, comprising:

Receiver And Transmitter, wherein,

Receiver is used for behind the channel information that estimates from transmitter to this receiver, range weight to described channel information carries out normalization, from the set of the code book that sets in advance, select again with normalization after the code book of the immediate amplitude normalization of channel information, as quantized channel information;

Transmitter is used to obtain the quantized channel information of a plurality of receivers, and the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information.

Preferably, described receiver comprises: memory module, normalization module, quantization modules and communication module, wherein,

Described memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance;

Described normalization module is used for the range weight of the channel information of place receiver is carried out normalization;

Described quantization modules reads code book set from memory module, from described code book set, select with normalization after the immediate code book of channel information as quantized channel information, and the quantized channel information index sent to communication module;

Described communication module is used for the quantized channel information index of described quantization modules output is reported transmitter.

Preferably, described transmitter comprises: memory module, computing module, precoding module and communication module, wherein,

Described memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance;

Described computing module is used for reading described code book set from described memory module, from described code book set, obtain the corresponding code book of index with described communication module output, quantized channel information as receiver, the channel matrix that the quantized channel information of a plurality of receivers is formed carries out the RQ decomposition, and calculates the intermediary matrix of pre-encode operation;

Described precoding module is used to utilize result that RQ decomposes and intermediary matrix that the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information;

Described communication module is used to receive the quantized channel information index of described a plurality of receivers.

Preferably, described transmitter further obtains the channel quality information of described a plurality of receivers, and according to described channel quality information calculate the signal interference ratio of each receiver and capacity and.

Preferably, described receiver further comprises: the channel quality information computing module, be used for calculating the channel quality information of place receiver, and send to the communication module of this receiver according to the quantization error between the quantized channel information of channel information after the normalization of described normalization module output and the output of described quantization modules;

The channel quality information that the communication module of described receiver is further used for receiving sends to described transmitter;

The communication module of described transmitter is further used for receiving the channel quality information that comes from receiver, and this channel quality information is sent to described computing module;

Described computing module further receives the channel quality information of the communication module that comes from described transmitter, and according to the channel quality information of a plurality of receivers calculate signal interference ratio and capacity and.

The present invention provides a kind of transmitter again, can improve the MU systematic function.

In transmitter of the present invention, comprising: memory module, computing module, precoding module and communication module, wherein,

Described memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance;

Described computing module is used for reading described code book set from described memory module, from described code book set, obtain the corresponding code book of index with described communication module output, quantized channel information as receiver, the channel matrix that the quantized channel information of a plurality of receivers is formed carries out the RQ decomposition, and calculates the intermediary matrix of pre-encode operation;

Described precoding module is used to utilize result that RQ decomposes and intermediary matrix that the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information;

Described communication module is used to receive the quantized channel information index of described a plurality of receivers.

Preferably, described memory module is further preserved the channel quality information of described a plurality of receivers;

Described computing module is further used for reading the channel quality information of described a plurality of receivers from memory module, and according to the channel quality information of a plurality of receivers calculate signal interference ratio and capacity and.

Preferably, communication module is further used for receiving the channel quality information that comes from receiver, and this channel quality information is sent to described computing module;

Described computing module further receives the channel quality information of the communication module that comes from described transmitter, and according to the channel quality information of a plurality of receivers calculate signal interference ratio and capacity and.

The present invention also provides a kind of receiver, can improve the MU systematic function.

In receiver of the present invention, comprising:

Memory module, normalization module, quantization modules and communication module, wherein,

Described memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance;

Described normalization module is used for the range weight of the channel information of place receiver is carried out normalization;

Described quantization modules reads code book set from memory module, from described code book set, select with normalization after the immediate code book of channel information as quantized channel information, and the quantized channel information index sent to communication module;

The quantized channel information index that described communication module is used for described quantization modules output reports transmitter.

Preferably, this receiver further comprises: the channel quality information computing module, be used for calculating the channel quality information of place receiver, and send to communication module according to the quantization error between the quantized channel information of channel information after the normalization of described normalization module output and the output of described quantization modules;

The channel quality information that described communication module is further used for receiving sends to transmitter.

By such scheme as seen, adopt the code book of amplitude normalization among the present invention, thereby in code book, keep CDI and get rid of the information relevant with the channel information amplitude.Like this, carrying out channel information when quantizing, only with CDI as considering content, selected code book can reflect real channel conditions more exactly more near actual channel; After transmitter utilizes the determined code book of receiver to carry out precoding, because the order of accuarcy of code book is higher, then can obtain bigger signal interference ratio, thus make system capacity and can access effective raising, and then make systematic function significantly be promoted.

In addition, adopt the code book of amplitude normalization among the present invention, promptly only reflect CDI, so just can with the shared code book of the linear predictive coding of other occasion, and save the operation that code book is set separately, the saving design cost.

Description of drawings

To make clearer above-mentioned and other feature and advantage of the present invention of those of ordinary skill in the art by describe exemplary embodiment of the present invention in detail with reference to accompanying drawing below, in the accompanying drawing:

Fig. 1 is existing THP method for precoding flow chart with Limited Feedback;

Fig. 2 is the exemplary process diagram of method for multi-user pre-coding among the present invention;

Fig. 3 is multi-user pre-coding system exemplary block diagram among the present invention;

Fig. 4 is the flow chart of method for multi-user pre-coding in the embodiment of the invention;

Fig. 5 is the structure chart of multi-user pre-coding system in the embodiment of the invention 1;

Fig. 6 is the flow chart of multi-user dispatching method in the embodiment of the invention 2;

Fig. 7 is the structure chart of multi-user pre-coding system in the embodiment of the invention 2;

Fig. 8 is the analogous diagram of the THP method for precoding of the method for multi-user pre-coding of the embodiment of the invention 2 and existing Limited Feedback;

Fig. 9 is method for multi-user pre-coding and the THP method for precoding of existing Limited Feedback and the analogous diagram of existing ZF multi-user pre-coding of the embodiment of the invention 1 or 2.

Embodiment

For making purpose of the present invention, technical scheme clearer, below with reference to the accompanying drawing embodiment that develops simultaneously, the present invention is described in further detail.

The present invention adopts the code book of amplitude normalization in the multi-user pre-coding process, i.e. the amplitude of the code book that comprises in the code book set is by normalization, and receiver carries out quantization operation again after self channel information is carried out normalization; And transmitter utilizes the code book of receiver correspondence, and the downlink data of a plurality of receivers is carried out pre-encode operation.

Fig. 2 shows the exemplary process diagram of method for multi-user pre-coding among the present invention.Referring to Fig. 2, this method comprises:

In step 201, set in advance the code book set of the code book that comprises amplitude normalization.

In step 202, receiver is behind the channel information that estimates from transmitter to this receiver, range weight to channel information carries out normalization, from code book set, select again with normalization after the immediate code book of channel information as described quantized channel information.

In step 203, transmitter obtains the quantized channel information of a plurality of receivers, and the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information.

Fig. 3 shows the exemplary block diagram of multi-user pre-coding system among the present invention.Referring to Fig. 3, this system comprises: transmitter and receiver.Wherein, receiver is used for behind the channel information that estimates from transmitter to this receiver, range weight to described channel information carries out normalization, from the set of the code book that sets in advance, select again with normalization after the code book of the immediate amplitude normalization of channel information, as quantized channel information; Transmitter is used to obtain the quantized channel information of a plurality of receivers, and the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information.

From the above description as seen, adopt the permanent mould code book of amplitude normalization in the embodiment of the invention, thereby in code book, keep CDI and get rid of the information relevant with the channel information amplitude.Like this, carrying out channel information when quantizing, only with CDI as considering content, selected code book can reflect real channel conditions more exactly more near actual channel; After transmitter utilizes the determined code book of receiver to carry out pre-encode operation, because the order of accuarcy of code book is higher, then can obtain bigger signal interference ratio, thus make system capacity and can access effective raising, and then make systematic function significantly be promoted.

In addition, adopt the permanent mould code book of amplitude normalization among the present invention, promptly only reflect CDI, so just can with the shared code book of the linear predictive coding of other occasion, and save the operation that code book is set separately, the saving design cost.

Below will describe concrete scheme of the present invention in detail by two embodiment.

Embodiment 1

In the present embodiment, receiver carries out being quantized to after the normalization code book of amplitude normalization in the code book set again to self channel information.

Fig. 4 shows the method flow diagram of multi-user pre-coding in the present embodiment.Referring to Fig. 4, this method comprises:

In step 401, set in advance the code book set of the code book that comprises amplitude normalization.

Code book in the present embodiment is the permanent mould code book of amplitude normalization, and promptly the mould of each code book is equal to 1.The line number of code book set here equals number of transmit antennas, and columns equals 2 ^N, wherein N is a number of bits of feedback.For example, be 4 at transmitting antenna, number of bits of feedback is in 4 the MU system, can the code book set be set to C=[C ₁, C ₂... C ₁₆], wherein: $C_1=\left[\begin{array}{c}-0.67762+0.31932i\\ 0.40199-0.14454i\\ 0.20758-0.42129i\\ 0.12487-0.14212i\end{array}\right],$ $C_2=\left[\begin{array}{c}0.49956+0.41557i\\ -0.19747-0.24041i\\ 0.32099-0.20195i\\ -0.32379-0.48197i\end{array}\right]$ $C_3=\left[\begin{array}{c}-0.073782+0.17199i\\ 0.49662-0.6807i\\ 0.32088-0.18775i\\ 0.13008-0.316i\end{array}\right]$ $C_4=\left[\begin{array}{c}-0.34399+0.22221i\\ -0.095697-0.15706i\\ 0.039345-0.37642i\\ 0.16569-0.79232i\end{array}\right]$ $C_5=\left[\begin{array}{c}0.76536-0.24285i\\ -0.12382-0.35194i\\ 0.16625+0.42884i\\ 0.018301+0.064614i\end{array}\right]$ $C_6=\left[\begin{array}{c}0.044038-0.2097i\\ 0.17185-0.10472i\\ -0.57108+0.33189i\\ 0.66342-0.19282i\end{array}\right]$ $C_7=\left[\begin{array}{c}-0.12836+0.14216i\\ -0.4616+0.44699i\\ 0.13556+0.22169i\\ -0.51599+0.46548i\end{array}\right]$ $C_8=\left[\begin{array}{c}0.16256-0.28509i\\ 0.79563+0.15475i\\ -0.13482+0.053847i\\ 0.14578-0.43931i\end{array}\right]$ $C_9=\left[\begin{array}{c}0.040329-0.37649i\\ -0.55039-0.39527i\\ 0.22574-0.43431i\\ 0.39601-0.032622i\end{array}\right]$ $C_{10}=\left[\begin{array}{c}-0.1772-0.20997i\\ 0.46359-0.33i\\ 0.17918+0.60302i\\ -0.33244+0.3073i\end{array}\right]$ $C_{11}=\left[\begin{array}{c}-0.66128+0.27068i\\ 0.42114+0.059052i\\ -0.10565-0.3209i\\ -0.049014-0.43824i\end{array}\right]$ $C_{12}=\left[\begin{array}{c}0.53408+0.074183i\\ -0.024851-0.10364i\\ 0.14359+0.14934i\\ 0.27874+0.75979i\end{array}\right]$ $C_{13}=\left[\begin{array}{c}-0.53138-0.40975i\\ 0.22735-0.19351i\\ -0.36569-0.38519i\\ -0.06254+0.41783i\end{array}\right]$ $C_{14}=\left[\begin{array}{c}-0.11988-0.5004i\\ -0.15445-0.046385i\\ 0.78374-0.16303i\\ -0.18364+0.1862i\end{array}\right]$ $C_{15}=\left[\begin{array}{c}-0.48963+0.1754i\\ -0.19488-0.47912i\\ -0.53231+0.38457i\\ 0.11579-0.13157i\end{array}\right]$ $C_{16}=\left[\begin{array}{c}-0.49825+0.49912i\\ 0.01413-0.32213i\\ 0.23418+0.07119i\\ -0.3935-0.42884i\end{array}\right].$

16 code book C among the above code book set C ₁, C ₂... C ₁₆Mould be 1, in other words, the amplitude of these 16 code books is constant.

In step 402, receiver carries out normalization to the range weight of self channel information behind the channel information that estimates from transmitter to this receiver.

The normalization here is meant, divided by the result to this channel information delivery, the channel information of promptly supposing receiver i correspondence is h with the channel information of receiver _i, then the channel information after the normalization is

Wherein || * || be modulo operation.

In step 403, receiver from code book set, select with normalization after the immediate code book of channel information as the quantized channel information of this receiver.

In this step, receiver in code book set, select and self normalization after channel information between the code book of vector differential mode minimum, and with the quantized channel information of this code book as self.Specifically, according to formula

Wherein

Be the quantized channel information of receiver, C _mBe m code book in the code book set, N is the code book sum in the code book set.

For example, when system comprises four receivers, each receiver has only a reception antenna, and the channel information of these four receivers is respectively:

${\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HSA00000037741600051.png"\; state="\{\{state\}\}">h</figure-callout>}}_1=\left[\begin{array}{c}0.093755-0.48865i\\ 1.522-3.2396i\\ 0.034439-2.1007i\\ 1.7076-1.3452\mathrm{<figure-callout\; id="2"\; label="i\; h"\; filenames="HSA00000037741600051.png"\; state="\{\{state\}\}">i</figure-callout>}& \\ \end{array},\right]$ $h_{}$ ${}_2=\left[\begin{array}{c}-1.9293-1.0091i\\ 0.25604+0.038035i\\ -2.6143+1.9753i\\ -0.24431-1.1979\mathrm{<figure-callout\; id="3"\; label="i\; h"\; filenames="HSA00000037741600051.png"\; state="\{\{state\}\}">i</figure-callout>}& \\ \end{array},\right]$ $h_{}$ ${}_3=\left[\begin{array}{c}-0.82703+0.2207i\\ 0.43871+0.36697i\\ -0.22606+0.8362i\\ -0.95331-1.8098\mathrm{<figure-callout\; id="4"\; label="i\; h"\; filenames="HSA00000037741600051.png,HSA00000037741600052.png"\; state="\{\{state\}\}">i</figure-callout>}& \\ \end{array},\right]$ $h_{}$ ${}_4=\left[\begin{array}{c}-1.2968+1.3692i\\ -0.17532-0.089873i\\ 0.1033+0.27019i\\ 0.89663+0.53384i\end{array}\right].$

After through normalization and quantification, the quantized channel information of determining above-mentioned four receivers is respectively C ₉, C ₁₃, C ₁₆, C ₄

In step 404, receiver reports transmitter with the quantized channel information index of self.

Owing to all there is code book set set in the step 401 in the transmitter and receiver, so receiver can be only reports transmitter with self the index of quantized channel information in the code book set as quantized channel information and gets final product.For example, for four receivers in the step 403, can report each self-corresponding code book index 9,13,16 and 4 to base station respectively as transmitter.

In step 405, transmitter obtains the quantized channel information of a plurality of receivers.

In this step, transmitter is after receiving the code book index of receiver feedback, and the corresponding code book of code book index that reads and receive from the code book set is with the code book that the reads quantized channel information as this receiver.

In step 406, the channel matrix that transmitter is formed the quantized channel information of a plurality of receivers carries out RQ and decomposes, and calculates the intermediary matrix of pre-encode operation.

In this step, transmitter at first multiply by the quantized channel information of this receiver to the CQI of the receiver that obtains in step 405, and then carries out RQ and decompose, promptly

Wherein R is the triangle battle array, and Q is a unitary matrice; Then, calculate the intermediary matrix B of pre-encode operation again according to following formula:

$G=\mathrm{diag}(R_{11}^{-1},R_{22}^{-1},...R_{\mathrm{MM}}^{-1}),B=\mathrm{GR}$

In step 407, transmitter utilizes result that RQ decomposes and intermediary matrix that the downlink data of a plurality of receivers is carried out pre-encode operation based on quantized channel information.

If receiver s transmits and is s _k, then the THP precoding in the present embodiment is satisfied:

$x_k=s_k+p_k-\underset{l=1}{\overset{M-1}{\mathrm{\&Sigma;}}}{b}_{\mathrm{kl}}{x}_l$

X wherein _kBe the data after the precoding,

M is the number of square planisphere modulation point, p _kEffect be to make that the data after the precoding are in the default scope so that improve the efficient of amplifier, b _KlData for the capable l row of the matrix B k in the abovementioned steps 406.

Pre-encode operation in this step is identical with the operation of existing method.

So far, the multi-user pre-coding flow process in the end present embodiment.

Fig. 5 shows the structure chart of multi-user pre-coding system in the present embodiment.Referring to Fig. 5, this system comprises: transmitter and receiver.

Specifically, transmitter comprises: memory module, computing module, precoding module and communication module.Wherein, memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance.Computing module is used for reading described code book set from described memory module, from described code book set, obtain the corresponding code book of index with described communication module output, quantized channel information as receiver, the channel matrix that the quantized channel information of a plurality of receivers is formed carries out the RQ decomposition, and calculates the intermediary matrix of pre-encode operation.Precoding module is used to utilize result that RQ decomposes and intermediary matrix that the downlink data of a plurality of receivers is carried out pre-encode operation based on described quantized channel information.Communication module is used to receive the quantized channel information index of a plurality of receivers, and is transferred to computing module.

Receiver comprises: memory module, normalization module, quantization modules and communication module.Memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance.The normalization module is used for the range weight of the channel information of place receiver is carried out normalization.Quantization modules reads code book set from memory module, from the code book set, select with normalization after the immediate code book of channel information as quantized channel information, and the quantized channel information index sent to communication module.Communication module is used for the quantized channel information index of quantization modules output is reported transmitter.

On the basis of above-mentioned multi-user pre-coding, transmitter can also further obtain the CQI of described receiver after obtaining the quantized channel information of receiver, so as to determine the SINR of each receiver and system capacity and.Owing to all need to use the CQI of receiver such as operations such as adaptive coding and modulating and user dispatch, and these operations are all in the execution of transmitter inside, and therefore, transmitter can self read the CQI that had calculated in the aforesaid operations.Like this, also preserve the CQI of receiver in the memory module of transmitter, the calculating of transmitter and precoding module also are used for reading from memory module the CQI of receiver so, and according to CQI calculate the signal interference ratio of each receiver and capacity and.For example, according to formula S INR _i=R _IiCQI _iCalculate signal interference ratio, wherein, SINR _iBe the signal interference ratio of receiver i, R _IiFor quantized channel information being carried out the diagonal entry of the triangular matrix R that RQ obtains in decomposing, CQI _iChannel quality information for receiver i.

In the present embodiment, the mould of each code book in the code book set is 1, that is to say that the code book in the present embodiment only comprises CDI, and do not comprise channel gain information (Channel Gain Information, CGI).Receiver is an index with CDI carrying out channel information when quantizing, make quantized channel information more near actual channel, can obtain bigger CQI and bigger signal to noise ratio, thereby make the capacity of system and being improved to a great extent, and then improve systematic function effectively.

Specifically, for the example in the present embodiment, the quantized channel information of four receivers is respectively code book 9,13,16 and 4, and transmitter is respectively from the CQI that self gets access to these four receivers that calculated: 0.96102,1.4548,1.3591 and 1.4598.The channel information that transmitter is formed the quantized channel information of four receivers carries out RQ and decomposes, and the Q matrix that obtains is:

$Q=\left[\begin{array}{cccc}-0.035946+0.33557i& 0.47363+0.36522i& 0.4441-0.44488i& 0.3066-0.19807i\\ 0.75519+0.53048i& -0.15647+0.16892i& -0.075189+0.2593i& 0.10342+0.1081i\\ -0.14392-0.010199i& 0.26135+0.56489i& -0.45797+0.36471i& -0.18833-0.46213i\\ 0.024169-0.11396i& 0.27715+0.35362i& -0.34245-0.26822i& -0.12287+0.76175i\end{array}\right]$

The R matrix that obtains is:

$R=\left[\begin{array}{cccc}-1.1219& 0& 0& 0\\ 0.0755-0.17967i& -0.80506& 0& 0\\ -0.45791+0.14998i& -0.22149-0.35708i& -0.60387& 0\\ 0.0076964-0.0007394i& 0.38329-0.091213i& -0.21052+0.42052i& 0.97668\end{array}\right]$

Then, transmitter is according to formula S INR=R _IiCQI _iCalculate signal interference ratio, wherein SINR is a signal interference ratio, CQI _iBe the CQI of i receiver, R _IiDiagonal entry for the R matrix.At this moment, the signal interference ratio that obtains four receivers is respectively: 1.2097,0.94288,0.49562 and 1.3925.So, the obtainable capacity of present embodiment multi-user pre-coding mode and be 3.94 bps/hertz (b/s/Hz).

On the other hand, for four receivers in the present embodiment, if the code book in the existing method of employing, then the quantized channel information of these receivers is respectively code book 16,1,6 and 11.Through the Q matrix that obtains after the RQ decomposition be:

$Q=\left[\begin{array}{cccc}-0.51672+0.20441i& 0.16293+0.015507i& -0.12286+0.34389i& 0.70321-0.19121i\\ -0.057187+0.48176i& -0.20183-0.2599i& -0.33196-0.71502i& 0.17774+0.057546i\\ 0.39905+0.26275i& 0.73839+0.37722i& 0.024698-0.15624i& 0.16642+0.17747i\\ -0.44654-0.16787i& 0.37048+0.2004i& -0.42216-0.20483i& -0.45466-0.41002i\end{array}\right]$

The R matrix that obtains is:

$R=\left[\begin{array}{cccc}-1.8306& 0& 0& 0\\ 0.025254+0.49408i& -1.0515& 0& 0\\ -0.33162+0.5502i& 0.55704+0.78426i& 1.6327& 1.6327\\ -0.65614-0.11739i& -0.90863-0.18119i& 0.059657+0.59838i& -1.6627\end{array}\right]$

The signal interference ratio of four receivers is respectively 0.21989,0.15655,0.75476 and 1.0653 in the existing method, capacity and be 2.35b/s/Hz.

As seen, under the identical situation of feedback bits, the multi-user pre-coding scheme in the present embodiment is than the capacity of existing Limited Feedback THP pre-coding scheme and high by 67.7%.

On the other hand, in the present embodiment, because transmitter inside is in the calculating of having finished such as occasions such as adaptive coding and modulating, user's scheduling receiver CQI, then transmitter only needs the CQI that reads receiver in the memory module of self to get final product, thereby makes obtaining of CQI more convenient quick.

Another aspect, owing to need not in precoding process, to pass through the CQI of Network Transmission receiver in the present embodiment, number of bits of feedback can all be used for transmitting the quantification channel information, compare with existing method so, can be provided with in the present embodiment and comprise the more code book set of code book, the approaching degree of quantized channel information and actual channel can be effectively improved, thereby further improves systematic function; Alternatively, under the situation that does not expand code book, can will be used for transmitting the feedback bits omission of receiver CQI originally, the number of bits of feedback in the precoding process reduces so, and the amount of information of Network Transmission reduces, and reduces network burden effectively, saves Internet resources.

Embodiment 2

In the present embodiment, receiver also calculates the CQI of self after the quantized channel information of determining self, and is transferred to transmitter together with quantized channel information; For transmitter, then be the CQI that gets access to receiver by the mode of communicating by letter with receiver.

Fig. 6 shows the flow chart of method for multi-user pre-coding in the present embodiment.Referring to Fig. 6, this method comprises:

In step 601, set in advance the code book set of the code book that comprises amplitude normalization.

In step 602～603, receiver carries out normalization to the range weight of self channel information behind the channel information that estimates from transmitter to this receiver; Receiver from code book set, select with normalization after the immediate code book of channel information as the quantized channel information of this receiver.

Above-mentioned three steps are identical to 403 operation with step 401 among the embodiment 1.

In step 604, channel information and quantization error quantized channel information between of receiver after according to normalization calculated the CQI of self.

In this step, the channel information of supposing the receiver correspondence is h _i, the channel information after the normalization is

Quantized channel information is

Receiver calculates the quantization error Δ of self earlier so _i, And then calculate CQI according to following formula:

${\mathrm{CQI}}_i=\frac{{\left|\right|h_i\left|\right|}^2\frac{P_0}{K\&CenterDot;{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HSA00000037741600051.png,HSA00000037741600052.png"\; state="\{\{state\}\}">N</figure-callout>}}_0}}{1+{\left|\right|h_i\left|\right|}^2{\left|\right|{\mathrm{\&Delta;}}_i\left|\right|}^2\frac{P_0}{{K\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HSA00000037741600051.png,HSA00000037741600052.png"\; state="\{\{state\}\}">N</figure-callout>}}_0}},$

Wherein, CQI _iBe the channel quality information of receiver i, P ₀Be transmitting power, N ₀Be the noise power of receiver, K is a number of transmit antennas, h _iChannel information for receiver i.

In step 605, receiver reports transmitter with self quantized channel information index and CQI.

In this step, receiver reports transmitter simultaneously with the CQI that calculates in the quantized channel information index determined in the step 603 and the step 604, and quantized channel information index and CQI all take feedback bits.

In step 606, transmitter is determined the quantized channel information and the CQI of receiver.

In this step, transmitter is except determining also directly to read the CQI of this receiver the quantized channel information of receiver from the information that receiver reports according to the mode of embodiment 1 step 405.

In step 607～608, the channel matrix that transmitter is formed the quantized channel information of a plurality of receivers carries out RQ and decomposes, and calculates the intermediary matrix of pre-encode operation; Transmitter utilizes result that RQ decomposes and intermediary matrix that the downlink data of a plurality of receivers is carried out pre-encode operation.

After this, transmitter can be according to the method for embodiment 1, the CQI that utilizes receiver to calculate calculate the SINR of each receiver and system capacity and.

So far, finish multi-user pre-coding flow process in the present embodiment.

Fig. 7 shows the structure chart of multi-user pre-coding system in the present embodiment.Referring to Fig. 7, the multi-user pre-coding system in the present embodiment is to have increased a CQI computing module on the basis of Fig. 5 in receiver inside.Specifically, difference between each module of transmitter in the present embodiment and receiver is: the CQI computing module is used for calculating the CQI of place receiver according to the quantization error between the quantized channel information of channel information after the normalization of normalization module output and quantization modules output, and sends to communication module; The CQI that the communication module of receiver is further used for receiving sends to transmitter.The communication module of transmitter is further used for receiving the CQI that comes from receiver, and this CQI is sent to computing module; Computing module further receives the channel quality information of the communication module that comes from described transmitter, and according to the channel quality information of a plurality of receivers calculate signal interference ratio and capacity and.

The calculating of CQI is finished by receiver in the present embodiment, so, and the plurality of advantages that the code book of amplitude normalization brings in having embodiment 1, obtaining of CQI is more direct, and transmitter need not to preserve the CQI of each receiver, saves storage resources, simplifies the structure of transmitter; In addition, present embodiment need not existing linear predictive coding system is carried out bigger change, has compatibility feature preferably, and the cost of constructing system is lower.

Fig. 8 shows the analogous diagram of the THP method for precoding of the method for multi-user pre-coding of the embodiment of the invention 2 and existing Limited Feedback.The simulated conditions of Fig. 8 is: 4 transmit antennas, and 4 receivers, each receiver is single antenna.No matter need to prove, be the THP precoding of existing Limited Feedback or the precoding among the embodiment 2, and quantized channel information all takies 5 feedback bits.As shown in Figure 8, the lines that have circle are represented the method for multi-user pre-coding of embodiment 2, and the lines that have square frame are represented the THP method for precoding of existing Limited Feedback.According to the emulation of Fig. 8, under the identical situation of signal to noise ratio, the capacity that method for multi-user pre-coding among the embodiment 2 obtains and apparently higher than the THP method of existing Limited Feedback, and under the lower situation of signal to noise ratio, the advantage of embodiment 2 is more obvious.

Fig. 9 shows method for multi-user pre-coding and the THP method for precoding of existing Limited Feedback and the analogous diagram of existing ZF multi-user pre-coding of the embodiment of the invention 1 or 2.Simulated conditions among Fig. 9 is identical with Fig. 7.As shown in Figure 9, the solid line lines that have circle are represented existing ZF method for multi-user pre-coding and are adopted 5 feedback bits carryings only to comprise the quantized channel information of CDI, the solid line lines that have square frame are represented existing ZF method for multi-user pre-coding and are adopted 10 feedback bits carryings only to comprise the quantized channel information of CDI, the dotted line lines that have a circle are represented in the embodiment of the invention 1 or 2 method for multi-user pre-coding and are adopted 5 feedback bits carryings only to comprise the quantized channel information of CDI, the dotted line lines that have a square frame are represented in the embodiment of the invention 1 or 2 method for multi-user pre-coding and are adopted 10 feedback bits carryings only to comprise the quantized channel information of CDI, the solid line lines that have a prismatic represent that existing ZF method for multi-user pre-coding and quantized channel information and actual channel are identical, and the dotted line lines that have a prismatic represent in the embodiment of the invention 1 or 2 that method for multi-user pre-coding and quantized channel information and actual channel are identical.Emulation from Fig. 9 as seen, under the same conditions, method for multi-user pre-coding of the present invention can than existing ZF method for multi-user pre-coding and existing Limited Feedback THP method for precoding obtain higher capacity and.

The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being made, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being made, is equal to replacement, improvement etc., all should be included within the scope of protection of the invention.

Claims (21)

1. a method for multi-user pre-coding is characterized in that, this method comprises:

Set in advance the code book set of the code book that comprises amplitude normalization;

Receiver carries out normalization to the range weight of described channel information behind the channel information that estimates from transmitter to this receiver, from described code book set, select again with normalization after the immediate code book of channel information as quantized channel information;

Transmitter obtains the quantized channel information of a plurality of receivers, and the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information.

2. method according to claim 1 is characterized in that, the described code book set that sets in advance the code book that comprises amplitude normalization is:

Be provided with that line number equals number of transmit antennas, columns equals 2 ^NCode book set, wherein N is a number of bits of feedback, and the mould of the code book of described amplitude normalization is 1.

3. method according to claim 1 is characterized in that, described transmitter obtains before the quantized channel information of a plurality of receivers, further comprises: receiver reports transmitter with described quantized channel information index.

4. according to claim 1 or 3 described methods, it is characterized in that, described from the set of described code book, select with normalization after the immediate code book of channel information as quantized channel information be:

From the set of described code book, select and normalization after channel information between the code book of vector differential mode minimum, and with this code book as described quantized channel information.

5. method according to claim 3 is characterized in that, the quantized channel information that described transmitter obtains a plurality of receivers is:

The quantized channel information index that transmitter reports according to receiver reads and the corresponding code book of this index from the set of described code book, with the code book that the reads quantized channel information as this receiver.

6. method according to claim 1 is characterized in that, described downlink data to described a plurality of receivers carry out based on the pre-encode operation of described quantized channel information be:

The channel matrix that transmitter is formed the quantized channel information of described a plurality of receivers carries out RQ and decomposes, and calculates the intermediary matrix of pre-encode operation;

Utilize result that RQ decomposes and intermediary matrix that the downlink data of described a plurality of receivers is carried out pre-encode operation.

7. method according to claim 3 is characterized in that, described receiver reports described quantized channel information index after the transmitter, further comprises:

Transmitter obtains the channel quality information of described a plurality of receivers, and according to described channel quality information calculate the signal interference ratio of each receiver and capacity and.

8. method according to claim 7 is characterized in that, the channel quality information that described transmitter obtains described a plurality of receivers is: transmitter is from self obtaining the channel quality information of described receiver.

9. method according to claim 7, it is characterized in that, described receiver reports described quantized channel information index before the transmitter, further comprises: receiver after according to normalization channel information and the quantization error between the described quantized channel information calculate the channel quality information of self;

Described transmitter obtains before the channel quality information of described a plurality of receivers, further comprises: receiver reports transmitter with the channel quality information of self;

The channel quality information that described transmitter obtains described a plurality of receivers is: receive the channel quality information that comes from receiver.

10. method according to claim 9 is characterized in that, channel information and quantization error described quantized channel information between the channel quality information that calculate self of described receiver after according to normalization is:

According to formula Calculate described quantization error, wherein Δ _iBe quantization error,

Be channel information h _iResult after the normalization, h _iBe the channel information of receiver i,

Be quantized channel information;

According to formula

Calculating channel quality information, wherein CQI _iBe the channel quality information of receiver i, P ₀Be transmitting power, N ₀Be the noise power of receiver, K is a number of transmit antennas.

11., it is characterized in that the signal interference ratio of described each receiver of calculating is according to any described method in the claim 7 to 9:

According to formula S INR _i=R _IiCQI _iCalculate signal interference ratio, wherein, SINR _iBe the signal interference ratio of receiver i, R _IiFor quantized channel information being carried out the diagonal entry of the triangular matrix R that RQ obtains in decomposing, CQI _iChannel quality information for receiver i.

12. a multi-user pre-coding system is characterized in that, this system comprises: Receiver And Transmitter, wherein,

Receiver is used for behind the channel information that estimates from transmitter to this receiver, range weight to described channel information carries out normalization, from the set of the code book that sets in advance, select again with normalization after the code book of the immediate amplitude normalization of channel information, as quantized channel information;

Transmitter is used to obtain the quantized channel information of a plurality of receivers, and the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information.

13. system according to claim 12 is characterized in that, described receiver comprises: memory module, normalization module, quantization modules and communication module, wherein,

Described memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance;

Described normalization module is used for the range weight of the channel information of place receiver is carried out normalization;

Described quantization modules reads code book set from described memory module, from described code book set, select with normalization after the immediate code book of channel information as quantized channel information, and the quantized channel information index sent to communication module;

Described communication module is used for the quantized channel information index of described quantization modules output is reported transmitter.

14. system according to claim 13 is characterized in that, described transmitter comprises: memory module, computing module, precoding module and communication module, wherein,

Described memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance;

Described computing module is used for reading described code book set from described memory module, from described code book set, obtain the corresponding code book of index with described communication module output, quantized channel information as receiver, the channel matrix that the quantized channel information of a plurality of receivers is formed carries out the RQ decomposition, and calculates the intermediary matrix of pre-encode operation;

Described precoding module is used to utilize result that RQ decomposes and intermediary matrix that the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information;

Described communication module is used to receive the quantized channel information index of described a plurality of receivers.

15. according to any described system in the claim 12 to 14, it is characterized in that described transmitter further obtains the channel quality information of described a plurality of receivers, and according to described channel quality information calculate the signal interference ratio of each receiver and capacity and.

16. according to claim 13 or 14 described systems, it is characterized in that, described receiver further comprises: the channel quality information computing module, be used for calculating the channel quality information of place receiver, and send to the communication module of this receiver according to the quantization error between the quantized channel information of channel information after the normalization of described normalization module output and the output of described quantization modules;

The channel quality information that the communication module of described receiver is further used for receiving sends to described transmitter;

The communication module of described transmitter is further used for receiving the channel quality information that comes from receiver, and this channel quality information is sent to described computing module;

Described computing module further receives the channel quality information of the communication module that comes from described transmitter, and according to the channel quality information of a plurality of receivers calculate signal interference ratio and capacity and.

17. a transmitter is characterized in that, this transmitter comprises: memory module, computing module, precoding module and communication module, wherein,

Described memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance;

Described computing module is used for reading described code book set from described memory module, from described code book set, obtain the corresponding code book of index with described communication module output, quantized channel information as receiver, the channel matrix that the quantized channel information of a plurality of receivers is formed carries out the RQ decomposition, and calculates the intermediary matrix of pre-encode operation;

Described precoding module is used to utilize result that RQ decomposes and intermediary matrix that the downlink data of described a plurality of receivers is carried out pre-encode operation based on described quantized channel information;

Described communication module is used to receive the quantized channel information index of described a plurality of receivers.

18. transmitter according to claim 17 is characterized in that, described memory module is further preserved the channel quality information of described a plurality of receivers;

Described computing module is further used for reading the channel quality information of described a plurality of receivers from memory module, and according to the channel quality information of a plurality of receivers calculate signal interference ratio and capacity and.

19. transmitter according to claim 17 is characterized in that, communication module is further used for receiving the channel quality information that comes from receiver, and this channel quality information is sent to described computing module;

Described computing module further receives the channel quality information of the communication module that comes from described transmitter, and according to the channel quality information of a plurality of receivers calculate signal interference ratio and capacity and.

20. a receiver is characterized in that, this receiver comprises: memory module, normalization module, quantization modules and communication module, wherein,

Described memory module is used to preserve the code book set of the code book that comprises amplitude normalization that sets in advance;

Described normalization module is used for the range weight of the channel information of place receiver is carried out normalization;

Described quantization modules reads code book set from memory module, from described code book set, select with normalization after the immediate code book of channel information as quantized channel information, and the quantized channel information index sent to communication module;

The quantized channel information index that described communication module is used for described quantization modules output reports transmitter.

21. receiver according to claim 20, it is characterized in that, this receiver further comprises: the channel quality information computing module, be used for calculating the channel quality information of place receiver, and send to communication module according to the quantization error between the quantized channel information of channel information after the normalization of described normalization module output and the output of described quantization modules;

The channel quality information that described communication module is further used for receiving sends to transmitter.

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