CN103220080B

CN103220080B - For the method and apparatus of quantization of channel state information

Info

Publication number: CN103220080B
Application number: CN201210031525.2A
Authority: CN
Inventors: 武露; 杨红卫; 米歇尔·佩吕耶罗; 让-皮埃尔·巴莱什
Original assignee: Alcatel Lucent Shanghai Bell Co Ltd; Alcatel Optical Networks Israel Ltd
Current assignee: Nokia Communications (Shanghai) Co., Ltd.; Alcatel Lucent SAS
Priority date: 2012-01-18
Filing date: 2012-01-18
Publication date: 2016-01-20
Anticipated expiration: 2032-01-18
Also published as: CN103220080A

Abstract

The invention discloses a method and device for quantizing channel state information. According to an embodiment of the present invention, it provides a method for providing a codeword index from a user terminal to a base station, and the base station is configured with N _t antennas configured with uniform circular arrays. The method includes: according to the estimated wideband channel matrix, the user terminal determines a first codeword in a first codebook of rank r based on a first predetermined criterion; wherein the first codeword is an estimation of a wideband channel direction A group of beams, r=1, 2, ... N _t ; sending the codeword index of the first codeword to the base station; for each subband, according to the estimated subband channel matrix, the user terminal based on the second predetermined criterion determining a second codeword in a second codebook of rank r, wherein the second codeword characterizes the subband channel direction and is a beam in the first codeword; and sending the codeword index of the second codeword to the base station . The present invention can obtain high system performance gain with relatively low PMI feedback overhead.

Description

Method and device for quantizing channel state information

技术领域 technical field

本发明是关于一种用于信道状态信息的方法与装置，尤其是关于一种产生用于量化无线通信系统中信道状态信息的方法与装置。The present invention relates to a method and device for channel state information, in particular to a method and device for generating channel state information for quantification in a wireless communication system.

背景技术 Background technique

众所周知，信道状态信息(CSI，ChannelStateInformation)量化是频分复用(FDD，FrequencyDivisionDuplex)系统中的一个关键问题，而均匀圆阵列(UCA，uniformcirculararray)则是一种常见的位于基站、如演进型节点基站(eNB，evolvedNodeBase)的天线结构，尤其是在用于热点(hotspot)覆盖的小的小区。由于缺乏适用于均匀圆阵列配置的码本，在量化用于均匀圆阵列的信道状态信息时，业内普遍使用原本为线性天线阵列设计的LTERel-10码本，而这势必会产生较大的量化误差。因此，业内亟需量化用于均匀圆阵列的信道状态信息的方法与装置。As we all know, channel state information (CSI, ChannelStateInformation) quantization is a key issue in frequency division multiplexing (FDD, Frequency Division Duplex) systems, and uniform circular array (UCA, uniform circular array) is a common An antenna structure of a base station (eNB, evolvedNodeBase), especially in a small cell for hotspot (hotspot) coverage. Due to the lack of codebooks suitable for uniform circular array configurations, when quantizing channel state information for uniform circular arrays, the industry generally uses the LTERel-10 codebook originally designed for linear antenna arrays, which will inevitably lead to large quantization error. Therefore, there is an urgent need in the industry for methods and devices for quantifying channel state information for uniform circular arrays.

发明内容 Contents of the invention

本发明的一个目的在于提供一种量化无线通信系统中信道状态信息的方法与装置，其适用于均匀圆阵列配置，在保证系统性能的同时具有较低的反馈开销。An object of the present invention is to provide a method and device for quantifying channel state information in a wireless communication system, which is suitable for a uniform circular array configuration and has low feedback overhead while ensuring system performance.

根据本发明的一实施例，其提供从用户终端向基站提供码字索引的方法，该基站配置有N_t根均匀圆阵列配置的天线。该方法包含：根据所估计的宽带信道矩阵，所述用户终端基于第一预定准则确定秩为r的第一码本中的第一码字；其中该第一码字是对宽带信道方向估计的一组波束，r＝1，2，…N_t；将该第一码字的码字索引发送至该基站；对于每个子带，根据所估计的子带信道矩阵，用户终端基于第二预定准则确定秩为r的第二码本中的第二码字，其中第二码字刻画子带信道方向，为第一码字中的一个波束；及将第二码字的码字索引发送至基站。According to an embodiment of the present invention, it provides a method for providing a codeword index from a user terminal to a base station, and the base station is configured with N _t antennas configured with uniform circular arrays. The method includes: according to the estimated wideband channel matrix, the user terminal determines a first codeword in a first codebook of rank r based on a first predetermined criterion; wherein the first codeword is an estimation of a wideband channel direction A group of beams, r=1, 2, ... N _t ; sending the codeword index of the first codeword to the base station; for each subband, according to the estimated subband channel matrix, the user terminal based on the second predetermined criterion determining a second codeword in a second codebook of rank r, wherein the second codeword characterizes the subband channel direction and is a beam in the first codeword; and sending the codeword index of the second codeword to the base station .

相应的，根据本发明的一实施例，其提供一种基站确定码字的方法。该方法包含：接收用户终端提供的秩为r的第一码本的第一码字的索引；接收用户终端提供的秩为r的第二码本的第二码字的索引；根据第一码字的索引，从秩为r的第一码本中确定第一码字；根据第二码字的索引，从秩为r的第二码本中确定第二码字；及基于第一码字与第二码字确定最终的码字。Correspondingly, according to an embodiment of the present invention, a method for determining a codeword by a base station is provided. The method includes: receiving the index of the first codeword of the first codebook with rank r provided by the user terminal; receiving the index of the second codeword of the second codebook with rank r provided by the user terminal; according to the first code The index of word, determine the first codeword from the first codebook that rank is r; According to the index of the second codeword, determine the second codeword from the second codebook that rank is r; And based on the first codeword and the second codeword to determine the final codeword.

根据本发明的一实施例，包含该第一码字与第二码字的码字W中的第r列表示为最终确定的码字W中的第r列表示为：According to an embodiment of the present invention, the rth column in the codeword W including the first codeword and the second codeword is expressed as the rth column in the finally determined codeword W is expressed as:

W(：，r)＝diag(D(：，r))*W_tmp(：，r)，r＝1，2，...，N_t W(:,r)=diag(D(:,r))*W _tmp (:,r), r=1, 2, . . . , N _t

其中W_tmp为所述秩为r的第一码本与第二码本中所述第一码字与第二码字的乘积，D为哈达玛矩阵。在一实施例中，为实现嵌套特性，哈达玛矩阵的第一列为全1或全-1。在另一实施例中，秩为r的第一码本C₁及其第k个第一码字W₁ ^(k)为：Wherein W _tmp is the product of the first codeword and the second codeword in the first codebook with rank r and the second codebook, and D is a Hadamard matrix. In one embodiment, to realize the nesting feature, the first column of the Hadamard matrix is all 1s or all -1s. In another embodiment, the first codebook C ₁ with rank r and its k-th first codeword W ₁ ^(k) are:

${C C}_{11} = = {{{W W}_{11}^{((00))},, {W W}_{11}^{((11))},, {W W}_{11}^{((22))},, \cdot \cdot \cdot \cdot \cdot \cdot,, {W W}_{11}^{((\frac{22 ((N N - - M m))}{M m} + + 11))}}}$

${W W}_{11}^{((k k))} = = [\begin{matrix} {b b}_{\frac{Mk Mk}{22} mod mod N N} & {b b}_{((\frac{Mk Mk}{22} + + 11)) mod mod N N} & \cdot \cdot \cdot \cdot \cdot \cdot & {b b}_{((\frac{Mk Mk}{22} + + M m - - 11)) mod mod N N} \end{matrix}],, k k = = 0,1 0,1,, \cdot &Center Dot; \cdot &Center Dot; \cdot &Center Dot;,, \frac{22 ((N N - - M m))}{M m} + + 11;;$

其中波束 $b_{\frac{Mk}{2} \mod N}, b_{(\frac{Mk}{2} + 1) \mod N}, . . . b_{(\frac{Mk}{2} + M - 1) \mod N}$ 表示为：where the beam $b_{\frac{Mk}{2} \mod N}, b_{(\frac{Mk}{2} + 1) \mod N}, . . . b_{(\frac{Mk}{2} + m - 1) \mod N}$ Expressed as:

${b b}_{n no} = = {[[{e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin {β β}_{p p} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{00})),,} {e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin {β β}_{p p} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{11}))},, . . . . . . {e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin {β β}_{p p} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{{N N}_{t t} - - 11}))}]]}^{T T},,$

$n = \frac{Mk}{2} \mod N, . . . (\frac{Mk}{2} + M - 1) \mod N,$ R是均匀圆阵列的半径，λ是该基站发射的电磁波的波长；N是用来对该基站发射的电磁波的水平方位角α在整个相位空间上的量化的数目，α∈[0，2π)；β_p是该基站发射的电磁波的仰角β在整个相位空间上进行P个量化时的第p个值，β∈[0，π)，p＝0，1，...P-1。 $no = \frac{Mk}{2} \mod N, . . . (\frac{Mk}{2} + m - 1) \mod N,$ R is the radius of the uniform circular array, λ is the wavelength of the electromagnetic wave emitted by the base station; N is the number used to quantify the horizontal azimuth angle α of the electromagnetic wave emitted by the base station in the entire phase space, α∈[0, 2π) ; β _p is the p-th value when the elevation angle β of the electromagnetic wave emitted by the base station is quantized for P times in the entire phase space, β∈[0, π), p=0, 1,...P-1.

在一实施例中，秩为r的第二码本C₂的第i个第二码字W₂ ⁽ⁱ⁾为：In an embodiment, the i-th second codeword W ₂ ⁽ⁱ⁾ of the second codebook C ₂ with rank r is:

其中是除第i+1个元素外均为0的M*1基本向量。in is an M*1 basic vector that is 0 except for the i+1th element.

此外，本发明还提供用于量化信道状态信息的装置。In addition, the present invention also provides a device for quantizing channel state information.

根据本发明的一实施例，本发明还提供一用户终端，其向基站提供码字索引，基站配置有N_t根均匀圆阵列配置的天线。该用户终端包含：第一码字确定装置，根据所估计的宽带信道矩阵，基于第一预定准则确定秩为r的第一码本中的第一码字，其中该第一码字是对宽带信道方向估计的一组波束，r＝1，2，…N_t；第一码字索引发送装置，将第一码字的码字索引发送至基站；第二码字确定装置，对于每个子带，根据所估计的子带信道矩阵，基于第二预定准则确定秩为r的第二码本中的第二码字，其中第二码字刻画子带信道方向，为第一码字中的一个波束；及第二码字索引发送装置，将第二码字的码字索引发送至基站。According to an embodiment of the present invention, the present invention also provides a user terminal, which provides a codeword index to a base station, and the base station is configured with N _t antennas configured with a uniform circular array. The user terminal includes: first codeword determining means, based on the estimated wideband channel matrix, and based on a first predetermined criterion, determine the first codeword in the first codebook with rank r, wherein the first codeword is for wideband A group of beams for channel direction estimation, r=1, 2, ... N _t ; the first codeword index sending means, sending the codeword index of the first codeword to the base station; the second codeword determining means, for each subband , according to the estimated subband channel matrix, determine the second codeword in the second codebook of rank r based on the second predetermined criterion, wherein the second codeword characterizes the subband channel direction and is one of the first codewords a beam; and a second codeword index sending device, for sending the codeword index of the second codeword to the base station.

根据本发明的一实施例，本发明还提供一基站，配置有N_t根均匀圆阵列配置的天线。该基站包含：第一码字索引接收装置，接收秩为r的第一码本的第一码字的索引，其中该第一码字是对宽带信道方向估计的一组波束，r＝1，2，…；第二码字索引接收装置，接收秩为r的第二码本的第二码字的索引，其中第二码字刻画子带信道方向，为第一码字中的一个波束；第一码字确定装置，根据第一码字的索引，从所述秩为r的第一码本中确定所述第一码字；第二码字确定装置，根据第二码字的索引，从秩为r的第二码本中确定第二码字；以及最终码字确定装置，基于第一码字与第二码字最终确定码字。According to an embodiment of the present invention, the present invention also provides a base station configured with N _t antennas configured in a uniform circular array. The base station includes: a first codeword index receiving device, which receives the index of the first codeword of the first codebook of rank r, wherein the first codeword is a group of beams for wideband channel direction estimation, r=1, 2, ...; The second codeword index receiving device receives the index of the second codeword of the second codebook of rank r, wherein the second codeword depicts the subband channel direction and is a beam in the first codeword; The first codeword determining means determines the first codeword from the first codebook whose rank is r according to the index of the first codeword; the second codeword determining means determines the first codeword according to the index of the second codeword, determining the second codeword from the second codebook with rank r; and final codeword determining means for finally determining the codeword based on the first codeword and the second codeword.

相较于现有技术，通过在均匀圆阵列配置中使用该发明的量化信道状态信息的方法与装置，其以简单的量化方式，在不增加预编码矩阵索引的反馈开销的情况下，极大提高系统性能增益。Compared with the prior art, by using the method and device for quantizing channel state information of the invention in a uniform circular array configuration, it uses a simple quantization method without increasing the feedback overhead of the precoding matrix index, greatly Improve system performance gain.

附图说明 Description of drawings

图1是根据本发明一实施例的用户终端提供码字索引给基站的流程图；FIG. 1 is a flowchart of a user terminal providing a codeword index to a base station according to an embodiment of the present invention;

图2是根据本发明一实施例的基站确定码字的流程图；Fig. 2 is a flowchart of determining a codeword by a base station according to an embodiment of the present invention;

图3是根据本发明一实施例的用于量化信道状态信息的系统结构方块图。FIG. 3 is a block diagram of a system structure for quantizing channel state information according to an embodiment of the present invention.

具体实施方式 detailed description

为更好的理解本发明的精神，以下结合本发明的部分优选实施例对其作进一步说明。In order to better understand the spirit of the present invention, it will be further described below in conjunction with some preferred embodiments of the present invention.

本发明的用于量化信道状态信息的方法和装置，提供包含两级反馈结构的码本。该码本包含两个预编码矩阵索引(PrecodingMatrixIndicator)，分别用于指示系统宽带的信道性能、及子带和/或短期的信道性能。在一实施例中，该量化信道状态信息的方法和装置用于均匀圆阵列配置。与LTERel-10码本相比，其可不增加预编码矩阵索引的反馈开销的情况下，显着提高系统性能。如本领域技术人员所了解的预编码矩阵索引与码字索引为相同概念，在本发明中会交替使用。The method and device for quantizing channel state information of the present invention provide a codebook including a two-stage feedback structure. The codebook includes two precoding matrix indices (PrecodingMatrixIndicator), which are respectively used to indicate the channel performance of the system wideband, and the subband and/or short-term channel performance. In one embodiment, the method and apparatus for quantizing channel state information are used in a uniform circular array configuration. Compared with the LTE Rel-10 codebook, it can significantly improve the system performance without increasing the feedback overhead of the precoding matrix index. As understood by those skilled in the art, the precoding matrix index and the codeword index are the same concept, and will be used interchangeably in the present invention.

根据本发明的一实施例，在下行链路多进多出(MIMO，MultipleInputMultipleOutput)系统中，基站，如eNB装配有N_t根天线，且该N_t根天线为均匀圆阵列配置。针对各个秩r，r＝0，1，…，N_t，分别构建对应的码本。各不同秩r的码本分别包含相应的第一码本与第二码本，其中第一码本包含若干第一码字，表示对宽带信道方向估计的一组波束(beam)，如M个相邻的波束；而第二码本包含若干第二码字，其选择第一码字中的一个波束用来刻画子带信道方向。而最终的码本，按照一定的规则基于第一码本和第二码本确定。具有不同秩的第一码本、第二码本、最终确定的码本，及最后码本的确定规则分别存储于基站与用户终端，用于量化信道状态信息。由用户终端提供量化信道状态信息的码字索引给基站，基站基于收到的码字索引确定码字而获得信道状态信息。According to an embodiment of the present invention, in a downlink Multiple Input Multiple Output (MIMO, Multiple Input Multiple Output) system, a base station, such as an eNB, is equipped with N _t antennas, and the N _t antennas are configured as uniform circular arrays. For each rank r, r=0, 1, . . . , N _t , construct corresponding codebooks. Codebooks of different ranks r include corresponding first codebooks and second codebooks, wherein the first codebooks include a number of first codewords, representing a group of beams (beams) for wideband channel direction estimation, such as M Adjacent beams; and the second codebook includes several second codewords, which select a beam in the first codeword to characterize the sub-band channel direction. The final codebook is determined based on the first codebook and the second codebook according to certain rules. The first codebook with different ranks, the second codebook, the finally determined codebook, and the determination rules of the final codebook are respectively stored in the base station and the user terminal for quantizing channel state information. The user terminal provides the codeword index of the quantized channel state information to the base station, and the base station determines the codeword based on the received codeword index to obtain the channel state information.

如图1所示，在本发明的一实施例中，用户终端提供量化信道状态信息的码字索引给基站。在步骤100中，用户终端根据所估计的宽带信道矩阵，基于一预定准则，如本领域技术人员所了解的容量最大化准则或距离最小化准则等，确定秩为r的第一码本C₁中的第一码字，其中该第一码字是对宽带信道方向估计的一组波束，r＝1，2，…N_t。As shown in FIG. 1 , in an embodiment of the present invention, a user terminal provides a codeword index of quantized channel state information to a base station. In step 100, the user terminal determines the _first codebook C with rank r based on a predetermined criterion, such as the capacity maximization criterion or distance minimization criterion known to those skilled in the art, according to the estimated wideband channel matrix The first codeword in , wherein the first codeword is a group of beams for wideband channel direction estimation, r=1, 2, ... N _t .

在步骤101中，用户终端将该确定的第一码字的码字索引发送至基站。In step 101, the user terminal sends the determined codeword index of the first codeword to the base station.

而对于每个子带，在步骤102中，用户终端则根据所估计的子带信道矩阵，也基于一预定准则(该预定准则可与确定第一码字的预定准则相同或不同)确定秩为r的第二码本中的第二码字，该第二码字刻画子带信道方向，是第一码字中的一个波束。For each subband, in step 102, the user terminal determines the rank r according to the estimated subband channel matrix and also based on a predetermined criterion (the predetermined criterion may be the same as or different from the predetermined criterion for determining the first codeword) The second codeword in the second codebook of , the second codeword characterizes the subband channel direction, is a beam in the first codeword.

在步骤103中，用户终端将第二码字的码字索引也发送至基站。In step 103, the user terminal also sends the codeword index of the second codeword to the base station.

相应的，在基站侧，如图2所示，在步骤200基站接收秩为r的第一码本的第一码字的索引。Correspondingly, at the base station side, as shown in FIG. 2 , in step 200, the base station receives the index of the first codeword of the first codebook with rank r.

在步骤201接收秩为r的第二码本的第二码字的索引。In step 201 an index of a second codeword of a second codebook of rank r is received.

在步骤202并根据第一码字的索引，从秩为r的第一码本中确定该第一码字。In step 202 and according to the index of the first codeword, the first codeword is determined from the first codebook with rank r.

在步骤203根据第二码字的索引，从秩为r的第二码本中确定该第二码字。In step 203, the second codeword is determined from the second codebook with rank r according to the index of the second codeword.

为获得最终的信道状态信息，在步骤204基站基于第一码字与第二码字确定最终码字。To obtain final channel state information, in step 204 the base station determines a final codeword based on the first codeword and the second codeword.

根据本发明的一实施例，在量化信道状态信息时，对表示宽带信道方向估计的第一码字的反馈周期要长于或对刻画子带信道方向的第二码字的反馈周期。换言之，将第一码字的码字索引发送至基站的周期长于或等于将第二码字的码字索引发送至基站的周期。基站在没有收到新的第一码字的索引情况下，会使用前一次的第一码字与新确定的第二码字来确定最终的码字。在第一码字的索引与第二码字的索引不包含其对应的码本的秩信息时，用户终端还需发送该秩信息给基站。According to an embodiment of the present invention, when the channel state information is quantized, the feedback period for the first codeword representing wideband channel direction estimation is longer than or for the second codeword describing subband channel direction. In other words, the period for sending the codeword index of the first codeword to the base station is longer than or equal to the period for sending the codeword index of the second codeword to the base station. If the base station does not receive the index of the new first codeword, it will use the previous first codeword and the newly determined second codeword to determine the final codeword. When the index of the first codeword and the index of the second codeword do not contain the rank information of their corresponding codebooks, the user terminal still needs to send the rank information to the base station.

此外，在确定第一码字的索引与第二码字的索引时，用户终端可使用不同的确定方式，如同时确定第一码字的索引、第二码字的索引；或先确定第一码字的索引，再确定第二码字的索引。In addition, when determining the index of the first codeword and the index of the second codeword, the user terminal can use different determination methods, such as determining the index of the first codeword and the index of the second codeword at the same time; or first determining the index of the first codeword The index of the codeword, and then determine the index of the second codeword.

相应的，上述实施例中的各步骤并不以书写的顺序而限定其实际的操作顺序，不应以此限定本发明的技术方案。Correspondingly, the actual operation sequence of the steps in the above embodiments is not limited by the written order, which should not limit the technical solution of the present invention.

以下进一步阐述根据本发明的一实施例，如何对信道状态信息进行量化，即产生用于量化信道状态信息的具有上述两级反馈结构的码本。The following further describes how to quantize channel state information according to an embodiment of the present invention, that is, to generate a codebook with the above-mentioned two-stage feedback structure for quantizing channel state information.

根据本发明的一实施例，在下行链路多进多出(MIMO，MultipleInputMultipleOutput)系统中，基站装配有N_t根天线，且该N_t根天线为均匀圆阵列配置，其中第n根天线的方位角为θ_n。由于各天线在同一圆周上均匀分配，θ_n可表示为：According to an embodiment of the present invention, in a downlink multiple-input multiple-output (MIMO, MultipleInputMultipleOutput) system, the base station is equipped with N _t antennas, and the N _t antennas are uniform circular array configurations, wherein the nth antenna The azimuth is θ _n . Since the antennas are evenly distributed on the same circle, θ _n can be expressed as:

${θ θ}_{n no} = = \frac{22 π π}{{N N}_{t t}} n no,, n no = = 0,1 0,1,, \cdot &Center Dot; \cdot \cdot \cdot &Center Dot; {N N}_{t t} - - 11$

将该基站发射的电磁波的发射角(AoD，AngleofDeparture)表示为(α，β)，其中α与β分别为该基站发射的电磁波的水平方位角和仰角。则基站至用户终端之间的信道矩阵的主要特征向量具有如下形式：The emission angle (AoD, Angle of Departure) of the electromagnetic wave emitted by the base station is expressed as (α, β), where α and β are respectively the horizontal azimuth angle and the elevation angle of the electromagnetic wave emitted by the base station. Then the main eigenvectors of the channel matrix between the base station and the user terminal have the following form:

$v v = = {[[{e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin β β cos cos ((α α - - {θ θ}_{00}))},, {e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin β β cos cos ((α α - - {θ θ}_{11}))},, \cdot \cdot \cdot \cdot \cdot \cdot,, {e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin β β cos cos ((α α - - {θ θ}_{{N N}_{t t - - 11}}))}]]}^{T T} - - - - - - ((11))$

其中α∈[0，2π)，β∈[0，π)，R是均匀圆阵列的半径，λ是基站发射的电磁波的波长。Where α∈[0, 2π), β∈[0, π), R is the radius of the uniform circular array, and λ is the wavelength of the electromagnetic wave emitted by the base station.

在本实施例中，基于该信道矩阵构建本发明的具有两级反馈结构的码本。针对各个秩rr＝0，1，...，N_t，构建对应的码本，各不同秩r的码本，包含相应的第一码本C₁与第二码本C₂。其中第一码本C₁包含若干第一码字W₁，表示对宽带信道方向估计的一组波束(beam)，如M个相邻的波束；而第二码本C₂包含若干第二码字W₂，其选择第一码字W₁中的一个波束用来刻画子带信道方向。In this embodiment, the codebook with a two-stage feedback structure of the present invention is constructed based on the channel matrix. For each rank _rr = ₀ , ₁ , . Wherein the first codebook C ₁ contains several first codewords W ₁ , representing a group of beams (beams) for wideband channel direction estimation, such as M adjacent beams; and the second codebook C ₂ contains several second codes Word W ₂ , which selects a beam in the first code word W ₁ to describe the sub-band channel direction.

可以将α与β在整个相位空间上分别均匀量化为N和P个值(在其它实施例中也可不进行均匀量化)，即：α and β can be uniformly quantized into N and P values in the entire phase space respectively (in other embodiments, uniform quantization may not be performed), namely:

$α α = = \frac{22 πn πn}{N N},, n no = = 0,1 0,1,, \cdot \cdot \cdot \cdot \cdot &Center Dot;,, N N - - 11;;$

${β β}_{p p} = = \frac{πp πp}{P P},, p p = = 0,1 0,1,, . . . . . .,, P P - - 11;;$

在β_p(对β在整个相位空间上进行P个量化时的第p个值)确定时，则第一码本C₁中的第一码字W₁中的波束表示为When β _p (the p-th value when β is quantized in the entire phase space for P times) is determined, then the beam in the first codeword W ₁ in the first codebook C ₁ is expressed as

${b b}_{n no} = = {[[{e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin {β β}_{p p} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{00})),,} {e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin {β β}_{p p} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{11}))},, . . . . . . {e e}^{- - j j \frac{22 πR πR}{λ λ} sin sin {β β}_{p p} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{{N N}_{t t} - - 11}))}]]}^{T T} - - - - - - ((22))$

通常出于简化考虑，仰角β设为因此等式(2)变为：Usually for the sake of simplicity, the elevation angle β is set as So equation (2) becomes:

${b b}_{n no} = = {[[{e e}^{- - j j \frac{22 πR πR}{λ λ} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{00}))},, {e e}^{- - j j \frac{22 πR πR}{λ λ} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{11}))},, \cdot &Center Dot; \cdot \cdot \cdot &Center Dot;,, {e e}^{- - j j \frac{22 πR πR}{λ λ} cos cos ((\frac{22 πn πn}{N N} - - {θ θ}_{{N N}_{t t} - - 11}))}]]}^{T T},, n no = = 0,1 0,1,, \cdot \cdot \cdot \cdot \cdot \cdot,, N N - - 11 - - - - - - ((33))$

当第一码字W₁包含M个相邻波束时，则第一码本C₁中的第k个第一码字W₁表示为：When the first codeword W ₁ contains M adjacent beams, the k-th first codeword W ₁ in the first codebook C ₁ is expressed as:

${W W}_{11}^{((k k))} = = [\begin{matrix} {b b}_{\frac{Mk Mk}{22} mod mod N N} & {b b}_{((\frac{Mk Mk}{22} + + 11)) mod mod N N} & \cdot &Center Dot; \cdot \cdot \cdot \cdot & {b b}_{((\frac{Mk Mk}{22} + + M m - - 11)) mod mod N N} \end{matrix}],, k k = = 0,1 0,1,, \cdot \cdot \cdot \cdot \cdot \cdot,, \frac{22 ((N N - - M m))}{M m} + + 11 - - - - - - ((44))$

本实施例中k代表第一码字W₁的索引，并依需要经编码后进行存储和传输。In this embodiment, k represents the index of the _first codeword W1, which is stored and transmitted after encoding as required.

第一码字W₁的第一码本C₁是The first codebook _C1 of the _first codeword W1 is

${C C}_{11} = = {{{W W}_{11}^{((00))},, {W W}_{11}^{((11))},, {W W}_{11}^{((22))},, \cdot \cdot \cdot \cdot \cdot \cdot,, {W W}_{11}^{((\frac{22 ((N N - - M m))}{M m} + + 11))}}} - - - - - - ((55))$

在本实施例中设定秩为1至N_t的第一码本C₁都相同。在其它实施列中，针对不同的秩可通过设定不同的N和M值获得不同的第一码本。In this embodiment, it is assumed that the first codebooks C ₁ with ranks 1 to N _t are all the same. In other embodiments, different first codebooks can be obtained for different ranks by setting different values of N and M.

第二码字W₂是选择具有相应秩的第一码字W₁中的一波束，即等式(4)中的一列。因此，秩为1的第二码本C₂中的第i个第二码字W₂是The second codeword W ₂ is to select a beam in the first codeword W ₁ with the corresponding rank, ie a column in equation (4). Therefore, the i-th second codeword W ₂ in the second codebook C ₂ of rank 1 is

${W W}_{22}^{((i i))} = = \frac{11}{\sqrt{{N N}_{i i}}} [[{\overset{~ ~}{e e}}_{i i}]],, i i = = 0,1 0,1,, \cdot \cdot \cdot \cdot \cdot \cdot,, M m - - 11 - - - - - - ((66))$

其中是除第i+1个元素外均为0的M*1基本向量。相应的，该秩为1的第二码本C₂表示为：in is an M*1 basic vector that is 0 except for the i+1th element. Correspondingly, the second codebook C ₂ with rank 1 is expressed as:

C₂＝{W₂ ⁽⁰⁾，W₂ ⁽¹⁾，…，W₂ ^(M-1))}(7)C ₂ ＝{W ₂ ⁽⁰⁾ ，W ₂ ⁽¹⁾ ，…，W ₂ ^(M-1) )}(7)

对于具有更高秩r的第二码本C₂，则其第i个第二码字W₂ ⁽ⁱ⁾表示为：For the second codebook C ₂ with higher rank r, its i-th second codeword W ₂ ⁽ⁱ⁾ is expressed as:

本实施例中i代表第二码字W₂的索引，并依需要经编码后进行存储和传输。In this embodiment, i represents the index of the second codeword W ₂ , which is stored and transmitted after encoding as required.

最后的码字W是基于第一码字W₁与第二码字W₂确定的。如为构建归一化的码本，使用哈达玛(Hadamard)矩阵进行线性变换并定义W_tmp＝W₁W₂，则最后的码字W的第r列表示为：The final codeword W is determined based on the _first codeword W1 and the _second codeword W2. For example, to construct a normalized codebook, a Hadamard matrix is used for linear transformation and W _tmp =W ₁ W ₂ is defined, then the rth column of the final codeword W is expressed as:

W(：，r)＝diag(D(：，r))*W_tmp(：，r)，r＝1，2，...，N_t(9)W(:,r)=diag(D(:,r))*W _tmp (:,r), r=1, 2, . . . , N _t (9)

其中D是哈达玛矩阵，例如：where D is the Hadamard matrix, for example:

$D D. = = [\begin{matrix} 11 & 11 & 11 & 11 & 11 & 11 & 11 & 11 \\ 11 & 11 & - - 11 & 11 & - - 11 & - - 11 & - - 11 & 11 \\ 11 & - - 11 & - - 11 & - - 11 & 11 & 11 & - - 11 & 11 \\ 11 & - - 11 & 11 & - - 11 & - - 11 & - - 11 & 11 & 11 \\ 11 & 11 & 11 & - - 11 & - - 11 & 11 & - - 11 & - - 11 \\ 11 & 11 & - - 11 & - - 11 & 11 & - - 11 & 11 & - - 11 \\ 11 & - - 11 & - - 11 & 11 & - - 11 & 11 & 11 & - - 11 \\ 11 & - - 11 & 11 & 11 & 11 & - - 11 & - - 11 & - - 11 \end{matrix}]$

以秩为1的最终码本为例，其码字W是W₁与W₂相乘，即Taking the final codebook with rank 1 as an example, its codeword W is multiplied by W ₁ and W ₂ , namely

W＝W₁W₂(10)W = W ₁ W ₂ (10)

此外，为使最终的码本具有嵌套特性，可选用第一列为全1或全-1的哈达玛矩阵。In addition, in order to make the final codebook have nesting characteristics, a Hadamard matrix whose first column is all 1 or all -1 can be selected.

具有不同秩的第一码本、第二码本、最终确定的码本，及最后码本的确定规则分别存储于基站与用户终端，用于量化信道状态信息。The first codebook with different ranks, the second codebook, the finally determined codebook, and the determination rules of the final codebook are respectively stored in the base station and the user terminal for quantizing channel state information.

本发明使用两级码本量化信道状态信息，其可以有效的平衡系统性能和预编码矩阵索引的反馈开销。具体的，其第一码字所需的比特数为第二码字所需的比特数为log₂(M)，M是第一码字中的波束数；总共需要的比特数为假定系统的带宽被划分为B个子带，在每个子带上反馈码字，则对于一级反馈结构的码本而言，其码本开销最小为Blog₂(N)比特，其中N是一级反馈结构的码本中的码本大小。显然，在N相同的情况下，本发明使用两级码本量化信道状态信息的方法较一级码本节省码字的反馈开销，同时在性能表现上，本发明也不逊色。The present invention uses a two-level codebook to quantize the channel state information, which can effectively balance the system performance and the feedback overhead of the precoding matrix index. Specifically, the number of bits required for the first codeword is The number of bits required for the second codeword is log ₂ (M), where M is the number of beams in the first codeword; the total number of bits required is Assuming that the bandwidth of the system is divided into B subbands, and a codeword is fed back on each subband, for a codebook with a one-stage feedback structure, its codebook overhead is at least Blog ₂ (N) bits, where N is a one-stage The codebook size in the codebook of the feedback structure. Obviously, in the case of the same N, the method of the present invention for quantizing channel state information using a two-stage codebook saves codeword feedback overhead compared with one-stage codebook, and at the same time, the present invention is not inferior in terms of performance.

示例性的，对于具有0.5波长的天线间距的8根天线的均匀圆阵列配置而言，即R＝0.25/sin(π/8)。假设N＝64，M＝8，则第一码本C₁的大小为4比特，而第二码本C₂的大小为3比特。以下详细列出了第一码本C₁与第二码本C₂设计：Exemplarily, for a uniform circular array configuration of 8 antennas with an antenna spacing of 0.5 wavelength, that is, R=0.25/sin(π/8). Assuming N=64 and M=8, the size of the first codebook C ₁ is 4 bits, and the size of the second codebook C ₂ is 3 bits. The first codebook C ₁ and the second codebook C ₂ designs are listed in detail below:

4比特的第一码本C₁及其第一码字W₁：4-bit first codebook C ₁ and its first codeword W ₁ :

${b b}_{n no} = = {[[{e e}^{- - j j \frac{22 πR πR}{λ λ} cos cos ((\frac{22 πn πn}{6464} - - {θ θ}_{00}))},, {e e}^{- - j j \frac{22 πR πR}{λ λ} cos cos ((\frac{22 πn πn}{6464} - - {θ θ}_{11}))},, \cdot &Center Dot; \cdot &Center Dot; \cdot &Center Dot;,, {e e}^{- - j j \frac{22 πR πR}{λ λ} cos cos ((\frac{22 πn πn}{6464} - - {θ θ}_{{N N}_{t t} - - 11}))}]]}^{T T},, n no = = 0,1 0,1,, \cdot &Center Dot; \cdot \cdot \cdot \cdot,, 6363$

W₁ ^(k)∈{[b_4kmod64b_(4k+1)mod64…b_(4k+7)mod64]：k＝0，1，…，15}W ₁ ^(k) ∈ {[b 4k _mod64 b _{(4k+1) mod64} ... b _{(4k+7) mod64} ]: k = 0, 1, ..., 15}

C₁＝{W₁ ⁽⁰⁾，W₁ ⁽¹⁾，W₁ ⁽²⁾，…，W₁ ⁽¹⁵⁾}C ₁ ＝{W ₁ ⁽⁰⁾ ，W ₁ ⁽¹⁾ ，W ₁ ⁽²⁾ ，…，W ₁ ⁽¹⁵⁾ }

3比特的第二码本C₂的第二码字W₂：The second codeword W ₂ of the second codebook C ₂ of 3 bits:

基于W₁和W₂的最后码本是 _The final codebook based _on W1 and W2 is

W(：，r)＝diag(D(：，r))*W_tmp(：，r)，r＝1，2，...，N_tN_t＝8W(:,r)=diag(D(:,r))*W _tmp (:,r), r=1, 2, . . . , N _t N _t =8

其中W_tmp＝W₁W₂ where W _tmp = W ₁ W ₂

本发明还提供用于量化信道状态信息的装置，其使用具有两级反锁结构的码本。The present invention also provides an apparatus for quantizing channel state information using a codebook with a two-stage anti-lock structure.

图3示例了根据本发明一实施例的量化信道状态信息的装置的系统框图，在该系统中，用户终端30向基站40提供码字索引，该基站40配置有N_t根均匀圆阵列配置的天线。用户终端30包含：第一码字确定装置300，其根据所估计的宽带信道矩阵，基于第一预定准则确定秩为r的第一码本中的第一码字，其中该第一码字是对宽带信道方向估计的一组波束，r＝1，2，…；第一码字索引发送装置301，其将第一码字的码字索引发送至基站；第二码字确定装置302，其对于每个子带，根据所估计的子带信道矩阵，基于第二预定准则确定秩为r的第二码本中的第二码字，其中第二码字刻画子带信道方向，其为第一码字中的一个波束；及第二码字索引发送装置303，将第二码字的码字索引发送至基站。FIG. 3 illustrates a system block diagram of a device for quantizing channel state information according to an embodiment of the present invention. In this system, a user terminal 30 provides a codeword index to a base station 40, and the base station 40 is configured with N _t uniform circular arrays. antenna. The user terminal 30 includes: first codeword determining means 300, which determines the first codeword in the first codebook of rank r based on the estimated wideband channel matrix based on the first predetermined criterion, wherein the first codeword is A group of beams for broadband channel direction estimation, r=1, 2, ...; the first codeword index sending means 301, which sends the codeword index of the first codeword to the base station; the second codeword determining means 302, which For each subband, according to the estimated subband channel matrix, the second codeword in the second codebook with rank r is determined based on the second predetermined criterion, wherein the second codeword characterizes the subband channel direction, which is the first a beam in the codeword; and the second codeword index sending means 303, which sends the codeword index of the second codeword to the base station.

相应的，基站40包含：第一码字索引接收装置400，其接收用户终端30提供的秩为r的第一码本的第一码字的索引；第二码字索引接收装置401，接收用户终端30提供的秩为r的第二码本的第二码字的索引；第一码字确定装置402，其根据第一码字的索引，从秩为r的第一码本中确定第一码字；第二码字确定装置403，根据第二码字的索引，从秩为r的第二码本中确定第二码字；以及最终码字确定装置404，基于第一码字与第二码字最终确定码字。Correspondingly, the base station 40 includes: first codeword index receiving means 400, which receives the index of the first codeword of the first codebook with rank r provided by the user terminal 30; second codeword index receiving means 401, which receives the index of the user The index of the second codeword of the second codebook whose rank is r provided by the terminal 30; the first codeword determining means 402, which determines the first codeword from the first codebook whose rank is r according to the index of the first codeword codeword; the second codeword determining means 403, according to the index of the second codeword, determines the second codeword from the second codebook whose rank is r; and the final codeword determining means 404, based on the first codeword and the first codeword The two code words finally determine the code word.

以下通过在系统层性能上仿真，进一步凸显本发明的优点。该仿真在具有19个六边形的小区下行链路的FFD系统中，分别使用了一用于均匀圆阵列的一级码本、LTERel-10码本、与本发明的具有两级反馈结构的码本。表1给出了具体的仿真参数与建模设定。基于表1的仿真参数与建模设定，表2、3、4分别给出了在将带宽划分给B个，B＝10时，各用于量化信道状态信息的不同码本所表现的系统性能和反馈开销。很显然，根据本发明的具有两级反馈结构的码本，相较于LTERel-10码本可以有显著的系统性能提升，而与一级码本相比可以很低的反馈开销获得相似的系统性能。In the following, the advantages of the present invention are further highlighted by simulating the performance of the system layer. In the FFD system with 19 hexagonal cell downlinks, the simulation uses a one-stage codebook for a uniform circular array, an LTEl-10 codebook, and the two-stage feedback structure of the present invention. codebook. Table 1 gives the specific simulation parameters and modeling settings. Based on the simulation parameters and modeling settings in Table 1, Tables 2, 3, and 4 respectively show the systems represented by different codebooks used to quantize channel state information when the bandwidth is divided into B, and B=10 Performance and feedback overhead. Obviously, the codebook with two-stage feedback structure according to the present invention can significantly improve the system performance compared with the LTE Rel-10 codebook, and can obtain a similar system with very low feedback overhead compared with the one-stage codebook performance.

表1仿真参数与建模设定Table 1 Simulation parameters and modeling settings

表2用于SU-MIMO的PMI反馈开销(B＝10)Table 2 PMI feedback overhead for SU-MIMO (B=10)

表3均匀圆阵列配置的8根天线的SU-MIMO性能Table 3 SU-MIMO performance of 8 antennas in uniform circular array configuration

表4均匀圆阵列配置的8根天线的SU/MU-MIMO性能Table 4 SU/MU-MIMO performance of 8 antennas in uniform circular array configuration

本发明的技术内容及技术特点已揭示如上，然而熟悉本领域的技术人员仍可能基于本发明的教示及揭示而作种种不背离本发明精神的替换及修饰。因此，本发明的保护范围应不限于实施例所揭示的内容，而应包括各种不背离本发明的替换及修饰，并为本专利申请权利要求书所涵盖。The technical content and technical features of the present invention have been disclosed above, but those skilled in the art may still make various substitutions and modifications based on the teaching and disclosure of the present invention without departing from the spirit of the present invention. Therefore, the protection scope of the present invention should not be limited to the content disclosed in the embodiments, but should include various replacements and modifications that do not depart from the present invention, and are covered by the claims of this patent application.

Claims

1. A method for quantizing channel state information, which provides a code from a user terminal to a base station

Word index, described base station is configured with the antenna of N _t uniform circular array configuration, comprises:

According to the estimated wideband channel matrix, the user terminal determines a first codeword in a first codebook of rank r based on a first predetermined criterion, where the first codeword is a group of beams for wideband channel direction estimation, r=1, 2, . . . N _t ;

sending a codeword index of the first codeword to the base station;

For each subband, according to the estimated subband channel matrix, the user terminal determines a second codeword in a second codebook of rank r based on a second predetermined criterion, wherein the second codeword characterizes the subband channel a direction, being a beam in the first codeword; and

sending the codeword index of the second codeword to the base station.

2. The method for quantizing channel state information as claimed in claim 1, wherein the r-th column in the codeword W comprising the first codeword and the second codeword is expressed as:

W(:,r)=diag(D(:,r))*W _tmp (:,r), r=1, 2, . . . , N _t

Wherein W _tmp is the product of the first codeword and the second codeword in the first codebook with rank r and the second codebook, and D is a Hadamard matrix.

3. The method for quantizing channel state information as claimed in claim 1 or 2, wherein said rank is the first codebook C ₁ of r and its kth first codeword W ₁ ^(k) is:

where the beam Expressed as

R is the radius of the uniform circular array, λ is the wavelength of the electromagnetic wave emitted by the base station; N is the number used to quantify the horizontal azimuth angle α of the electromagnetic wave emitted by the base station in the entire phase space, α∈[0, 2π) M is the number of beams in the first codeword; β _p is the p-th value when the elevation angle β of the electromagnetic wave emitted by the base station is carried out on the entire phase space for P quantization, β ∈ [0, π), p=0,1,...P-1; θ _n is the azimuth angle of the nth antenna, and N _t is the number of antennas installed in the base station.

4. The method for quantizing channel state information as claimed in claim 3, wherein the i-th second codeword W ₂ ⁽ⁱ⁾ of the second codebook C ₂ of r in said rank is:

in is an M*1 basic vector that is 0 except for the i+1th element.

5. The method for quantizing channel state information as claimed in claim 1, wherein the cycle of sending the codeword index of the first codeword to the base station is longer than or equal to sending the codeword index of the second codeword The period at which the index is sent to the base station.

6. The method for quantizing channel state information according to claim 2, wherein the first column of the Hadamard matrix is all 1s or all -1s.

7. A base station determines a method for a codeword, the codeword has a two-stage feedback structure, and the base station is configured with an antenna of N _t root uniform circular array configurations, comprising:

Receiving an index of a first codeword of a first codebook of rank r, wherein the first codeword is a group of beams for wideband channel direction estimation, r=1, 2,... N _t ;

receiving an index of a second codeword of a second codebook of rank r, wherein the second codeword depicts a subband channel direction and is a beam in the first codeword;

determining the first codeword from the first codebook of rank r according to the index of the first codeword;

determining the second codeword from the second codebook of rank r according to the index of the second codeword; and

The codeword is finally determined based on the first codeword and the second codeword.

8. The method according to claim 7, wherein the r-th column in the finally determined codeword W is expressed as:

W(:,r)=diag(D(:,r))*W _tmp (:,r), r=1, 2, . . . , N _t

9. The method as claimed in claim 7 or 8, wherein said rank is the first codebook C ₁ of r and the kth first codeword W ₁ ^(k) thereof is

where the beam Expressed as

R is the radius of the uniform circular array, λ is the wavelength of the electromagnetic wave emitted by the base station; N is the number used to quantify the horizontal azimuth angle α of the electromagnetic wave emitted by the base station in the entire phase space, α∈[0, 2π) ; β _p is the pth value when the elevation angle β of the electromagnetic wave emitted by the base station is carried out on the entire phase space for P quantization, β ∈ [0, π), p=0, 1, ... P-1; θ _n is the azimuth angle of the nth antenna, and N _t is the number of antennas installed in the base station.

10. The method as claimed in claim 9, wherein the i-th second codeword W ₂ ⁽ⁱ⁾ of the second codebook C ₂ of r in the rank is:

in is an M*1 basic vector that is 0 except for the i+1th element.

11. The method of claim 8, wherein the first column of the Hadamard matrix is all ones or all -1s.

12. A user terminal, which provides a codeword index to a base station, the base station is configured with N _t antennas configured with a uniform circular array, and the user terminal includes:

The first codeword determining means is used to determine the first codeword in the first codebook of rank r based on the estimated wideband channel matrix based on the first predetermined criterion, wherein the first codeword is an estimate of the wideband channel direction. Group of beams, r=1, 2, ... N _t ;

a first codeword index sending device, for sending the codeword index of the first codeword to the base station;

The second codeword determining means, for each subband, according to the estimated subband channel matrix, determines the second codeword in the second codebook of rank r based on the second predetermined criterion, wherein the second codeword describes The subband channel direction is a beam in the first codeword; and

The second codeword index sending device is configured to send the codeword index of the second codeword to the base station.

13. The user terminal according to claim 12, wherein the r-th column in the codeword W comprising the first codeword and the second codeword is expressed as:

W(:,r)=diag(D(:,r))*W _tmp (:,r), r=1, 2, . . . , N _t

14. The user terminal according to claim 12 or 13, wherein the rank r is the first codebook C ₁ and the kth first codeword W ₁ ^(k) thereof is:

where the beam Expressed as

15. The user terminal according to claim 14, wherein the i-th second codeword W ₂ ⁽ⁱ⁾ of the second codebook C ₂ whose rank is r is:

in is an M*1 basic vector that is 0 except for the i+1th element.

16. A base station configured with N _t root uniform circular array antennas, comprising:

The first codeword index receiving device receives the index of the first codeword of the first codebook whose rank is r, wherein the first codeword is a group of beams for wideband channel direction estimation, r=1, 2, .. .N _t ;

The second codeword index receiving device is configured to receive an index of a second codeword of a second codebook of rank r, wherein the second codeword depicts a subband channel direction and is a beam in the first codeword;

The first codeword determining device is configured to determine the first codeword from the first codebook with rank r according to the index of the first codeword;

The second codeword determining means determines the second codeword from the second codebook of rank r according to the index of the second codeword; and

The final codeword determining device finally determines the codeword based on the first codeword and the second codeword.

17. The base station according to claim 16, wherein the r-th column in the finally determined codeword W is expressed as:

W(:,r)=diag(D(:,r))*W _tmp (:,r), r=1, 2, . . . , N _t

18. The base station as claimed in claim 16 or 17, wherein the first codebook C ₁ and the kth first codeword W ₁ ^{(k) of the r first codebook C 1 (k)} are:

where the beam Expressed as

19. The base station according to claim 18, wherein the i-th second codeword W ₂ ⁽ⁱ⁾ of the second codebook C2 whose rank is r is:

in is an M*1 basic vector that is 0 except for the i+1th element.