WO2016180058A1 - 一种基于波束运算和分组平均的lte-a双码本预编码选择方法 - Google Patents
一种基于波束运算和分组平均的lte-a双码本预编码选择方法 Download PDFInfo
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- WO2016180058A1 WO2016180058A1 PCT/CN2016/073259 CN2016073259W WO2016180058A1 WO 2016180058 A1 WO2016180058 A1 WO 2016180058A1 CN 2016073259 W CN2016073259 W CN 2016073259W WO 2016180058 A1 WO2016180058 A1 WO 2016180058A1
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- H—ELECTRICITY
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- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04B7/0478—Special codebook structures directed to feedback optimisation
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- the invention belongs to the field of wireless communication technologies, and relates to an LTE-A 8 antenna spatial multiplexing dual codebook precoding selection algorithm, in particular to a LTE-A dual codebook precoding selection method based on beam operation and packet averaging.
- the 3GPP LTE-A (LTE-Advanced) project is an evolution of LTE (Long Term Evolution), corresponding to LTE Release 10 and later.
- Carrier aggregation technology in LTE-A supports a maximum bandwidth of 100 MHz, a downlink peak rate of 1 Gbit/s, and a peak spectrum efficiency of 30 bits/s/Hz.
- LTE-A downlink supports up to 8 transmit antennas for data transmission, supports up to 8 layers of spatial multiplexing mode, and uses a dual codebook precoding scheme.
- codebook 1 has 16 matrices, each matrix consists of 4 beam vectors, and codebook 2 consists of angled selection vectors, which have 16 matrices, so there are 256 precodings.
- matrix For layer 3 and layer 4, codebook 1 has 4 matrices, each matrix consists of 8 beam vectors, codebook 2 consists of angled selection vectors, layer 3 has 16 matrices, and layer 4 has 8 The matrix, so layer 3 and layer 4 have 64 and 32 precoding matrices, respectively.
- the gain of precoding is not obvious, so the number of bits of PMI is correspondingly reduced.
- the dual codebook design brings a huge amount of codebook, which increases the complexity of the codebook selection.
- the spatial multiplexing mode needs to select an appropriate precoding matrix according to the channel, and the mutual information maximization criterion can be used to select a suitable precoding matrix.
- the mutual information amount of subcarrier k is represented by I k and is expressed by the following equation, where L represents the number of transmission layers:
- the precoding matrix W selected from the codebook needs to maximize the sum of the mutual information amounts of the respective subcarriers.
- This method needs to calculate the mutual information amount on all subcarriers of the entire bandwidth, so it is called a full bandwidth mutual information criterion.
- MI-SC Mutual Information Selection Criterion
- the LTE system supports multiple bandwidth configurations (1.4 MHz to 20 MHz), which means that the number of RBs is 1 to 100, and each RB has 12 subcarriers. For each precoding matrix, a minimum of 12 times and a maximum of 1200 are required. Secondary mutual information.
- the present invention provides a LTE-A dual codebook precoding selection method based on beam operation and packet averaging, which achieves the consistency of the precoding effect and greatly Reduce the computational complexity.
- the LTE-A dual codebook precoding selection method based on beam operation and packet averaging includes the following steps:
- K is the number of subcarriers for the entire bandwidth and c is a constant. Indicates that an integer is taken;
- step (3) For each channel, traverse all the number of packets M i calculated in step (2), select the maximum number of packets as the number of packets of the channel, and select the maximum number of packets under all channels in the entire bandwidth as the entire bandwidth.
- phase modulation channel in step (5) The expression is as follows:
- Phase modulation parameter Related to the number of transmission layers, when the number of transmission layers is 1 or 2, the phase modulation parameters The value is ⁇ 1, -1, j, -j ⁇ ; when the number of transmission layers is 3, the phase modulation parameter The value is ⁇ 1, -1 ⁇ ; when the number of transmission layers is 4, the phase modulation parameter The value is ⁇ 1, -1, j, -j ⁇ .
- step (6) the expression of the beam vector b q corresponding to the number of transmission layers is 1-4:
- the expression of the mutual information amount I j in the step (7) is:
- the signal-to-noise ratio SINR j,l on the jth channel of the first layer is related to the channel estimation mode.
- W is a precoding matrix
- I L is an L-order identity matrix
- the precoding selection algorithm of the present invention can be applied to the dual codebook precoding selection of LTE-A 8 antenna spatial multiplexing, and is optimized for the transport layer 1 to 4 layers, and the original mutual information maximization criterion Compared with the precoding algorithm, the consistency of the precoding effect is maintained, and the computational complexity is greatly reduced.
- 1 is a flowchart of a LTE-A dual codebook precoding selection method based on beam operation and packet averaging;
- 3 is a multiplication number required for calculating the mutual information amount of the transport layer 1 to 4 layers when the receiving antenna is 4;
- 4 is a number of additions required for calculating the mutual information amount of the transport layer 1 to 4 layers when the receiving antenna is 4;
- 5 is a matrix inverse number required for calculating the mutual information amount of the transport layer 1 to 4 layers when the receiving antenna is 4;
- FIG. 6 is a comparison diagram of packet numbers in different bandwidth configurations and channels according to the present invention.
- the air interface model applied to the heterogeneous network convergence of WLAN and LTE includes the following steps:
- step (3) traversing the number of all the packets calculated in step (2), selecting the maximum number of packets as the number of packets of the channel, and then selecting the maximum number of packets under all channels in the entire bandwidth as the number of packets M of the entire bandwidth;
- the beam-based channel information calculation process for all channels is divided into 2 steps:
- the average channel matrix H j is divided into two channel matrices of the same four columns, and the phase modulation parameters of the 1 to 4 layers are calculated. They are:
- the beam vector b q to be calculated when the number of transmission layers is 1 to 4 is respectively selected from the corresponding beam vector matrix B:
- W is a precoding matrix
- I L is an L-order identity matrix
- the precoding matrix W uses a dual codebook design for the cross-polarized 8 antenna according to the adaptive precoding technique, using the beam vector b q and the phase modulation parameter Expressed as:
- b q2 can select q 1 , q 1 +1, q 1 +3, 3 kinds of vectors;
- b q2 can select q 1 , q 1 +1, q 1 +2, 3 vectors.
- b m1 , b m2 , b m3 have the following four combinations:
- the codebook 1 and the codebook 2 are no longer traversed, and the traversal beam and the phase modulation parameters are replaced. After the beam and the phase modulation parameters are determined, the value of the HW can be obtained by checking the first step. The table is obtained.
- 3 to 5 are comparison results of the multiplication, addition, matrix inverse and full-band mutual information criterion calculations required to calculate the mutual information of one channel for all codebooks.
- the results show that the number of multiplications and additions are significantly reduced.
- the number of matrix inverses is reduced.
- Figure 6 is a comparison of the number of channels required to calculate the present invention and the full bandwidth MI-SC under the extended pedestrian channel model EPA, extended typical urban channel model ETU, extended vehicle channel model EVA with bandwidth of 1.4, 5, 10, 20 MHz. The results show that the number of calculated channels required by the present invention is much smaller than the full bandwidth MI-SC.
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Abstract
本发明公开了一种基于波束运算和分组平均的LTE-A双码本预编码选择方法,针对LTE-A 8天线空间复用模式中传输层数1~4所采用的双码本预编码,以互信息量最大化为准则,通过遍历波束向量和调相参数,并存储调相信道与波束的乘积,使得互信息的计算可以通过查表获得,解决了现有技术中选取预编码矩阵所存在的大量重复计算问题,该发明采用分组平均的思想,对整个带宽的子载波进行分组,利用每组信道的平均值计算互信息量,大幅减少所需计算的信道数。在不损失预编码性能的前提下,大幅减少了复数乘法、加法及矩阵逆运算的次数,降低了计算复杂度。
Description
本发明属于无线通信技术领域,涉及LTE-A 8天线空间复用双码本预编码选择算法,尤其涉及一种基于波束运算和分组平均的LTE-A双码本预编码选择方法。
3GPP LTE-A(LTE-Advanced)项目是LTE(Long Term Evolution)的演进,对应LTE Release 10以及以后的版本。LTE-A中通过载波聚合技术,最大支持带宽100MHz,下行峰值速率可到1Gbit/s,峰值频谱效率可达到30bit/s/Hz。
为达到峰值频谱效率,LTE-A下行支持多达8个发射天线进行数据传输,支持多达8层的空间复用模式,并采用了双码本的预编码方案。对于层1和层2来说,码本1共有16个矩阵,每个矩阵由4个波束向量组成,码本2由经过调角的选择向量组成,共有16个矩阵,因此共有256个预编码矩阵。对于层3和层4来说,码本1共有4个矩阵,每个矩阵由8个波束向量组成,码本2由经过调角的选择向量组成,层3有16个矩阵,层4有8个矩阵,因此层3和层4分别有64和32个预编码矩阵。对于层5~8,预编码的增益并不明显,因此PMI的比特数相应减少,5~7层时只有4个预编码矩阵,而8层的预编码则是固定的。对于1~4层来说,双码本设计带来了巨大的码本量,提高了码本选择的复杂度。
空间复用模式需要根据信道选择合适的预编码矩阵,使用互信息量最大化准则可以很好的选择合适的预编码矩阵。
用Ik表示子载波k的互信息量,由下式表示,式中L表示传输层数:
从码本中选择的预编码矩阵W需要使各个子载波互信息量之和最大化,这种方法需要计算整个带宽所有子载波上的互信息量,因此称之为全带宽互信息量准则。
采用全带宽互信息量准则(Mutual Information Selection Criterion,MI-SC)选择预编码矩阵的缺点在于计算复杂度非常高。其计算复杂度来源于两个方面:1)首先,为了确定合适的预编码矩阵,需要遍历码本中每个预编码矩阵。8天线双码本设计中,可选的预编码矩阵量较大,预编码矩阵量的增加将增大计算复杂度,对于1~4层,1和2层的
矩阵数为256个,3层、4层分别为64和32个。2)另一方面,其计算复杂度随着带宽增大,子载波数目的增多而增大。LTE***支持多种带宽配置(1.4MHz~20MHz),这意味着RB个数为1~100个,每个RB有12个子载波,则对于每一个预编码矩阵,需要计算最少12次,最多1200次互信息量。
发明内容
发明目的:为了克服现有技术中存在的不足,本发明提供一种基于波束运算和分组平均的LTE-A双码本预编码选择方法,达到既保持预编码效果的一致性的同时,又大幅降低了计算复杂度的效果。
技术方案:为实现上述目的,本发明提供的基于波束运算和分组平均的LTE-A双码本预编码选择方法,包括如下步骤:
(1)在频域中针对整个带宽上的任意信道,遍历寻找所有子载波所对应的信道频率响应幅值中的所有极大、极小值,计算两相邻极大、极小值之间的差并取绝对值,记为ΔHi,并计算两相邻极大、极小值之间的子载波数Δki,i=0,1,…,N-2,N为极值的个数;
(2)根据每一个ΔHi计算该信道下整个带宽所需的分组数Mi,Mi的表达式如下:
(3)针对每个信道,遍历步骤(2)中所计算的所有分组数Mi,选取最大分组数作为该信道的分组数,再选择整个带宽内所有信道下最大的分组数作为整个带宽的分组数M;
(8)选择使得互信息量之和最大的波束向量和调相参数组合作为最终选择的预编码矩阵。
其中,步骤(6)中传输层数为1~4时分别对应的波束向量bq的表达式如下:
其中,步骤(7)中所述互信息量Ij的表达式为:
第l层第j个信道上的信噪比SINRj,l与信道估计方式有关,
对于ZF检测:
有益效果:本发明的预编码选择算法能应用于LTE-A 8天线空间复用的双码本预编码选择,针对传输层为1~4层进行了优化,与原始的互信息量最大化准则选择预编码算法相比,保持了预编码效果的一致性的同时,大幅降低了计算复杂度。
图1为基于波束运算和分组平均的LTE-A双码本预编码选择方法的流程图;
图2为本发明中调相信道和波束乘积存储流程图;
图3为本发明在接收天线为4时,传输层1~4层计算互信息量所需的乘法次数;
图4为本发明在接收天线为4时,传输层1~4层计算互信息量所需的加法次数;
图5为本发明在接收天线为4时,传输层1~4层计算互信息量所需的矩阵逆次数;
图6为本发明在不同带宽配置和各信道下的分组数比较图。
下面结合实施例对本发明作更进一步的说明。
图1中,针对LTE-A 8天线空间复用传输模式下传输层1~4层的双码本预编码,本发明的基于波束运算和分组平均的LTE-A双码本预编码选择方法,应用于WLAN与LTE的异构网融合的空中接口模型中,包括以下步骤:
(1)在频域中针对整个带宽上的任意信道,遍历寻找所有子载波所对应的信道频率响应幅值中的所有极大、极小值(极大、极小值间隔出现),计算两相邻极大、极小值之间的差并取绝对值,记为ΔHi,并计算两相邻极大、极小值之间的子载波数Δki,i=0,1,…,N-2,N为极值的个数;
(3)遍历步骤(2)中所计算的所有分组数,选取最大分组数作为该信道的分组数,再选择整个带宽内所有信道下最大的分组数作为整个带宽的分组数M;
(8)选择使得所述所有信道互信息量之和最大的波束向量和调相参数组合作为最终选择的预编码矩阵。
基于波束的所有信道互信息量计算过程分为2步:
(1)计算调相信道和波束的乘积,存入查找表中,过程如图2所示:
传输层数为1~4时所需计算的波束向量bq分别从相应的波束向量矩阵B中选取:
针对不同的检测方式,信噪比SINRj,l的计算公式不同,
对于选定波束向量bq1,q1={0,1,…,31}:
如果其下标值q1为偶数,则bq2可以选q1、q1+1、q1+3,3种向量;
如果其下标值q1为奇数,则bq2可以选q1、q1+1、q1+2,3种向量。
其中,q1={0,1,…,15},q2=(q1+4)mod16。
层4:
计算所需的中间变量HjW的具体计算公式为:
bm1、bm2、bm3有如下4种组合:
{bq1,bq1,bq2},{bq2,bq1,bq2},{bq1,bq2,bq2},{bq2,bq1,bq1}
其中,q1={0,1,…,15},q2=(q1+4)mod16。
层4:
图3~5为本发明遍历所***本计算一个信道的互信息量所需的乘法、加法、矩阵逆次数与全带宽互信息量准则计算的对比结果。结果显示乘法和加法次数都有显著下降,在层1和层2时,矩阵逆次数有所减少。
图6为带宽为1.4、5、10、20MHz配置在扩展步行者信道模型EPA、扩展典型城市信道模型ETU、扩展车辆信道模型EVA下本发明和全带宽MI-SC所需计算的信道个数对比,结果显示,本发明所需的计算的信道数目远远小于全带宽MI-SC。
Claims (5)
- 一种基于波束运算和分组平均的LTE-A双码本预编码选择方法,其特征在于,该方法包括如下步骤:(1)在频域中针对整个带宽上的任意信道,遍历寻找所有子载波所对应的信道频率响应幅值中的所有极大、极小值,计算两相邻极大、极小值之间的差并取绝对值,记为ΔHi,并计算两相邻极大、极小值之间的子载波数Δki,i=0,1,…,N-2,N为极值的个数;(2)根据每一个ΔHi计算该信道下整个带宽所需的分组数Mi,Mi的表达式如下:(3)针对每个信道,遍历步骤(2)中所计算的所有分组数Mi,选取最大分组数作为该信道的分组数,再选择整个带宽内所有信道下最大的分组数作为整个带宽的分组数M;(8)选择使得互信息量之和最大的波束向量和调相参数组合作为最终选择的预编码矩阵。
- 根据权利要求1中所述的双码本预编码选择方法,其特征在于,步骤(2)中常数c的取值为1.25。
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WO2019037694A1 (zh) * | 2017-08-21 | 2019-02-28 | 华为技术有限公司 | 波束指示和上报方法、网络设备、终端 |
CN114204972A (zh) * | 2022-02-18 | 2022-03-18 | 上海擎昆信息科技有限公司 | 一种秩指示和预编码矩阵索引的计算方法、接收端设备 |
CN114204972B (zh) * | 2022-02-18 | 2022-06-07 | 上海擎昆信息科技有限公司 | 一种秩指示和预编码矩阵索引的计算方法、接收端设备 |
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