WCDMA系统中MIMO预编码的研究
摘要
支持MIMO技术的WCDMA HSPA+是3G到4G的过渡阶段,这一阶段通过在收发端引入多天线技术,将发射端信源输出的串行码转换成多路并行的子码流,在同一频段通过不同的发射天线同时发送。MIMO这个4G系统特有技术的引用,使频率资源得到重复利用,从而在原有的频带内实现信息高速率的传输。
支持MIMO技术的WCDMA系统,虽然得益于多天线提供高速率传输,但也在多径干扰的基础上引入更多的码间干扰。码间干扰产生的根本原因是带宽受限和时延扩展,传统的解决方法是在接收端进行均衡处理。本文通过列举几个常用的均衡方法研究了均衡算法的复杂度,如果在下行链路中,均衡算法的复杂度无法消减的话,作为接收端的移动通信设备使用接收滤波器就必须加大体积,以便携为特点的移动接收机是无法做到的。预编码技术就以简化接收端信号处理的目的逐渐发展起来。
预编码有线性和非线性之分:线性预编码得益于其实现简单的特点,成为无线移动通信系统最常采用的方法;非线性预编码虽然可以更接近信道容量上限,但其实现的复杂度过大。
本文通过研究SVD预编码和通信协议中采用的基于码本的预编码,总结了线性预编码的设计标准,并研究了将码本的方式应用于SVD预编码中。
本文还提出了一种综合的相位预编码,其设计思想是在接收端用实、虚部点乘法检测两信道中相互正交的信号,预编码矩阵需要做到消除信道的相位干扰,并且将两天线上的信号正交化。相比几种常用的预编码方法,其差别是并没有彻底改善有效信道的状态,而是以简化信号检测为目的。
WCDMA HSPA+ which supports MIMO is transition phase from 3G to 4G. In this period, through introducing MIMO, it transforms original serial code to parallel multichannel sub-streams, and scents them from different antennas in the same frequency band. MIMO which is the peculiarly technology in 4G makes frequency resource reuse to achieve high-speed transmission in original frequency band.
Although MIMO offers high-speed transmission, WCDMA with MIMO imports more inter-symbol interference (ISI) in the base of multi-path interference. The basic reasons of ISI are constrained strip width and time-delay spreading, equalization in the receiving end which is traditional method can handle it. This paper cite some common equalization method and discuss their complexity which is master key in the downlink, because if we can’t cut down the complexity, the phone behaved as receiving end must enlarge its size. However special with portable feature, the phone can’t accept the reality. To simplify the complexity of the receiving end, precoding technology developed by and by.
Precoding includes linear and nonlinear. With simple realization, linear precoding is adopted generally. Although nonlinear precoding can approach the upper limit of channel capacity, it’s defeated because of the implement’s complexity.
This paper summarized the criterion of precoding designing by research SVD precoding and the method of codebook which is adopted by communication protocol. And the paper attempted at importing the codebook into SVD precoding.
Also the paper put forward a synthetic phase precoding. The idea of designing is that the receiving end detect orthotropic signal with dot product between real and imaginary part. So the precoding needs to remove the phase interference of the channel, and orthogonalize the signals from two antennas. Compare with common precoding, it aims at simplified detecting process instead of modify resultful channel thoroughly.
支持MIMO技术的WCDMA系统,虽然得益于多天线提供高速率传输,但也在多径干扰的基础上引入更多的码间干扰。码间干扰产生的根本原因是带宽受限和时延扩展,传统的解决方法是在接收端进行均衡处理。本文通过列举几个常用的均衡方法研究了均衡算法的复杂度,如果在下行链路中,均衡算法的复杂度无法消减的话,作为接收端的移动通信设备使用接收滤波器就必须加大体积,以便携为特点的移动接收机是无法做到的。预编码技术就以简化接收端信号处理的目的逐渐发展起来。
预编码有线性和非线性之分:线性预编码得益于其实现简单的特点,成为无线移动通信系统最常采用的方法;非线性预编码虽然可以更接近信道容量上限,但其实现的复杂度过大。
本文通过研究SVD预编码和通信协议中采用的基于码本的预编码,总结了线性预编码的设计标准,并研究了将码本的方式应用于SVD预编码中。
本文还提出了一种综合的相位预编码,其设计思想是在接收端用实、虚部点乘法检测两信道中相互正交的信号,预编码矩阵需要做到消除信道的相位干扰,并且将两天线上的信号正交化。相比几种常用的预编码方法,其差别是并没有彻底改善有效信道的状态,而是以简化信号检测为目的。
WCDMA HSPA+ which supports MIMO is transition phase from 3G to 4G. In this period, through introducing MIMO, it transforms original serial code to parallel multichannel sub-streams, and scents them from different antennas in the same frequency band. MIMO which is the peculiarly technology in 4G makes frequency resource reuse to achieve high-speed transmission in original frequency band.
Although MIMO offers high-speed transmission, WCDMA with MIMO imports more inter-symbol interference (ISI) in the base of multi-path interference. The basic reasons of ISI are constrained strip width and time-delay spreading, equalization in the receiving end which is traditional method can handle it. This paper cite some common equalization method and discuss their complexity which is master key in the downlink, because if we can’t cut down the complexity, the phone behaved as receiving end must enlarge its size. However special with portable feature, the phone can’t accept the reality. To simplify the complexity of the receiving end, precoding technology developed by and by.
Precoding includes linear and nonlinear. With simple realization, linear precoding is adopted generally. Although nonlinear precoding can approach the upper limit of channel capacity, it’s defeated because of the implement’s complexity.
This paper summarized the criterion of precoding designing by research SVD precoding and the method of codebook which is adopted by communication protocol. And the paper attempted at importing the codebook into SVD precoding.
Also the paper put forward a synthetic phase precoding. The idea of designing is that the receiving end detect orthotropic signal with dot product between real and imaginary part. So the precoding needs to remove the phase interference of the channel, and orthogonalize the signals from two antennas. Compare with common precoding, it aims at simplified detecting process instead of modify resultful channel thoroughly.
引文
[1]康丽. MIMO线性预编码和脏纸编码性能研究. [硕士论文],云南:昆明理工大学,2007
[2]施风.移动通信中MIMO系统的线性预编码研究. [博士论文],南京:东南大学,2005
[3]周志刚,程时昕,陈明,王海峰. MIMO HSDPA系统中分数采样的空时均衡接收方案.电路与系统学报,Vol.9, No.4, August.2004
[4]刘毅. MIMO信道预编码技术研究. [博士论文],西安:西安电子科技大学,2007
[5] Mai Vu, Arogyaswami Paulraj. MIMO Wireless Linear Precoding. IEEE Signal Processing Magazine, Vol:24, No:5, SEPTEMBER 2007
[6]章俊,刘国庆,刘力军,田晨.多径信道衰落与时延的模拟研究.南京工业大学学报,Vol.28, No.2, Mar.2006
[7]张晓娜. OFDM系统中基于预编码的半盲信道估计算法研究. [硕士论文],长春:吉林大学,2008
[8]李海涛,林孝康.单载波通信系统中的注水预编码技术.西安电子科技大学学报. Vol.35, No.6, Dec.2008
[9] Shang-Ho Tsai. Transmit Equal Gain Precoding in Rayleigh Fading Channels. IEEE Signal Processing, Vol:57, No:9, SEPTEMBER 2009
[10]傅华.多用户MIMO下行系统的预编码和用户调度. [博士论文],武汉:华中科技大学,2007
[11]李有明,沈微,王让定,李新苗.基于对角块分解的下行方向快速预编码算法.通信学报. Vol.30, No.6,June 2009
[12]孙丽红,李鸿林.基于多用户MIMO系统的下行链路的预编码.信息技术,2009
[13]周燕琳.频率选择性信道下的MIMO检测和预编码技术研究. [硕士论文],成都:电子科技大学,2006
[14] Chun Yang Chen, P. P. Vaidyanathan. Precoded V-BLAST for ISI MIMO Channels. IEEE Circuits and Systems, 2006
[15]奚家熹.无线通信中的预编码技术. [博士论文],上海:复旦大学,2007
[16]刘伟,张春阳,邵珠雷.相关衰落信道中星座预编码和球译码
[17]谢红,戈琪.新型准正交空时分组编码预编码的设计.应用科技, Vol.36, No.7, Jul.2009
[18] Tetsushi Abe, Gerhard Bauch. Differential Codebook MIMO Precoding Technique. IEEE Global Telecommunications Conference, 2007,753:3963-3968
[19]无线通信系统信道估计技术研究与实现. [硕士论文],北京:北京邮电大学
[20]张捷,王江宏,崔新瑞,李海峰. HSDPA MIMO系统的预编码技术的应用研究.通信技术. Vol.41, No.04, 2008
[21]聂永萍,胡昌恩,何先刚. MIMO信道的均衡技术研究.西华师范大学学报,Vol.26, No.3, 9.2005
[22] Daryl Rrynolds, Anders Host-Madsen, Xiaodong Wang. Adaptive Transmitter Precoding for Time Division Duplex CDMA in Fading Multipath Channels: Strategy and Analysis. EURASIP Journal on Applied Signal Processing, 2002:12,1325-1334
[23]聂永萍,胡昌恩.宽带多入多出系统的迭代均衡技术.重庆工商大学学报,Vol.22, No.6, 12.2005
[24]常萌,申敏. 16QAM解调算法及其在HSDPA中的应用.技术论坛,No.2,2006
[25] Shakti Prasad Shenoy, Irfan Ghauri, Dirk T. M. Slock.. Optimal Precoding and MMSE Receiver Designs for MIMO WCDMA. IEEE Vehicular Technology Conference, 2008.193:893-897
[26]黄敏,缪蔚,周世东,王京. MIMO系统中基于TH预编码的多用户空间复用方案.清华大学学报,Vol.48, No.4, 2008
[27]贾蓉,武刚,何旭.多用户MIMO信道下行链路预编码方案对比研究.电子科技大学学报,Vol.37增刊, 6.2008
[28] Seunghun Jang, Janghoon Yang, Seungyeon Eom, Dong Ku Kim. A Near Optimal Linear Precoding for Multiuser MIMO Throughput Maximization. IEEE Vehicular Technology Conference, 2008,173:792-796
[29] Ulises Pineda Rico, Emad Alsusa, Christos Masouros. A simple low-complexity precoding technique for MIMO systems. IEEE Wireless Communications and Networking Conference, 2007.208:1098-1102
[30]郑义,刘芳.无线通信中的线性预编码技术应用与研究.现代电子技术,2006
[31] Waleed Al-Hanafy, Andrew P. Millar, Chi Hieu Ta, Stephan Weiss. Broadband SVD and Non-Linear Precoding Applied to Broadband MIMO Channels. IEEE Signals Systems and Computers, 2008,42:2053-2057
[32]王岩. MIMO广播信道预编码技术研究. [硕士论文],云南:昆明理工大学,2007
[33] Veljko Stankovic, Martin Haardt. Generalized Design of Multi-User MIMO Precoding Mateices. IEEE Wireless Communications, Vol:7, No:3, MARCH 2008
[34] Christoph Windpassinger, Robert F. H. Fischer, Johannes B. Huber. Lattice-Reduction-Aided Broadcast Precoding. IEEE Communications, Vol:52, No:12, DECEMBER 2004
[35]闫晓鹏. MIMO系统中的信号检测与预编码技术研究. [硕士论文],北京:北京邮电大学,2007
[36] F. Keskin, J. Hahn, P. W. Baier. Minimum energy soft precoding. IEEE Electronics Letters, Vol:43, No:6, MARCH 2007
[37] Chunyan Gao, Mihai Enescu, Xiao Guang Che. On the Feasibility of SVD-Based Downlink Precoding in future TDD system. IEEE Personal Indoor and Mobile Radio Communications, 2007,4394635:1-5
[38] Yang Xu, Tho Le-Ngoc. Optimal Power Allocation with Channel Inversion Regularization-Based Precoding for MIMO Broadcast Channels. EURASIO Journal on Advances in Signal Processing, 2008
[39]张齐治,朱旭明,易清明,李健,黄元.移动通信中MQAM调制方式的优化选择——瑞利衰落信道中MQAM传输误码性能的分析.无线电工程,Vol.32, No.2, 2002
[40] Weihua Zhuang, W. Vincent Huang. IEEE Vehicular Technology, Vol:46, No:1, FEBRUARY 1997
[41] Michael Joham, Hans Brunner, Raphael Hunger, David A. Schmidt, Wolfgang Utschick. Point-to-Point MIMO MMSE Vector Precoding and THP Achieving Capacity. IEEE Acoustics Speech and Signal Processing, 1-4244-1484-9/08, 2008
[42] Hamid Farmanbar, Amir K. Khandani. Precoding for the AWGN Channel With Discrete Interference. IEEE Information Theory, Vol:55, No:9, SEPTEMBER 2009
[43]杨鹏,葛建华.多输入多输出系统下低复杂度的自适应预编码方法.西安交通大学学报. Vol.41, No.4, Apr.2007
[44] Yongming Huang, Luxi Yang, Mats Bengtsson, Bjorn Ottersten. A Codebook-Based Precoding for Dual-hop Downlink with MIMO Amplify-and-Forward Relaying. IEEE Signal Processing Advances in Wireless Communication, 2009:245-249
[45]郑贱平. MIMO通信系统中的信号检测与预编码技术研究. [博士论文],西安:西安电子科技大学,2008
[2]施风.移动通信中MIMO系统的线性预编码研究. [博士论文],南京:东南大学,2005
[3]周志刚,程时昕,陈明,王海峰. MIMO HSDPA系统中分数采样的空时均衡接收方案.电路与系统学报,Vol.9, No.4, August.2004
[4]刘毅. MIMO信道预编码技术研究. [博士论文],西安:西安电子科技大学,2007
[5] Mai Vu, Arogyaswami Paulraj. MIMO Wireless Linear Precoding. IEEE Signal Processing Magazine, Vol:24, No:5, SEPTEMBER 2007
[6]章俊,刘国庆,刘力军,田晨.多径信道衰落与时延的模拟研究.南京工业大学学报,Vol.28, No.2, Mar.2006
[7]张晓娜. OFDM系统中基于预编码的半盲信道估计算法研究. [硕士论文],长春:吉林大学,2008
[8]李海涛,林孝康.单载波通信系统中的注水预编码技术.西安电子科技大学学报. Vol.35, No.6, Dec.2008
[9] Shang-Ho Tsai. Transmit Equal Gain Precoding in Rayleigh Fading Channels. IEEE Signal Processing, Vol:57, No:9, SEPTEMBER 2009
[10]傅华.多用户MIMO下行系统的预编码和用户调度. [博士论文],武汉:华中科技大学,2007
[11]李有明,沈微,王让定,李新苗.基于对角块分解的下行方向快速预编码算法.通信学报. Vol.30, No.6,June 2009
[12]孙丽红,李鸿林.基于多用户MIMO系统的下行链路的预编码.信息技术,2009
[13]周燕琳.频率选择性信道下的MIMO检测和预编码技术研究. [硕士论文],成都:电子科技大学,2006
[14] Chun Yang Chen, P. P. Vaidyanathan. Precoded V-BLAST for ISI MIMO Channels. IEEE Circuits and Systems, 2006
[15]奚家熹.无线通信中的预编码技术. [博士论文],上海:复旦大学,2007
[16]刘伟,张春阳,邵珠雷.相关衰落信道中星座预编码和球译码
[17]谢红,戈琪.新型准正交空时分组编码预编码的设计.应用科技, Vol.36, No.7, Jul.2009
[18] Tetsushi Abe, Gerhard Bauch. Differential Codebook MIMO Precoding Technique. IEEE Global Telecommunications Conference, 2007,753:3963-3968
[19]无线通信系统信道估计技术研究与实现. [硕士论文],北京:北京邮电大学
[20]张捷,王江宏,崔新瑞,李海峰. HSDPA MIMO系统的预编码技术的应用研究.通信技术. Vol.41, No.04, 2008
[21]聂永萍,胡昌恩,何先刚. MIMO信道的均衡技术研究.西华师范大学学报,Vol.26, No.3, 9.2005
[22] Daryl Rrynolds, Anders Host-Madsen, Xiaodong Wang. Adaptive Transmitter Precoding for Time Division Duplex CDMA in Fading Multipath Channels: Strategy and Analysis. EURASIP Journal on Applied Signal Processing, 2002:12,1325-1334
[23]聂永萍,胡昌恩.宽带多入多出系统的迭代均衡技术.重庆工商大学学报,Vol.22, No.6, 12.2005
[24]常萌,申敏. 16QAM解调算法及其在HSDPA中的应用.技术论坛,No.2,2006
[25] Shakti Prasad Shenoy, Irfan Ghauri, Dirk T. M. Slock.. Optimal Precoding and MMSE Receiver Designs for MIMO WCDMA. IEEE Vehicular Technology Conference, 2008.193:893-897
[26]黄敏,缪蔚,周世东,王京. MIMO系统中基于TH预编码的多用户空间复用方案.清华大学学报,Vol.48, No.4, 2008
[27]贾蓉,武刚,何旭.多用户MIMO信道下行链路预编码方案对比研究.电子科技大学学报,Vol.37增刊, 6.2008
[28] Seunghun Jang, Janghoon Yang, Seungyeon Eom, Dong Ku Kim. A Near Optimal Linear Precoding for Multiuser MIMO Throughput Maximization. IEEE Vehicular Technology Conference, 2008,173:792-796
[29] Ulises Pineda Rico, Emad Alsusa, Christos Masouros. A simple low-complexity precoding technique for MIMO systems. IEEE Wireless Communications and Networking Conference, 2007.208:1098-1102
[30]郑义,刘芳.无线通信中的线性预编码技术应用与研究.现代电子技术,2006
[31] Waleed Al-Hanafy, Andrew P. Millar, Chi Hieu Ta, Stephan Weiss. Broadband SVD and Non-Linear Precoding Applied to Broadband MIMO Channels. IEEE Signals Systems and Computers, 2008,42:2053-2057
[32]王岩. MIMO广播信道预编码技术研究. [硕士论文],云南:昆明理工大学,2007
[33] Veljko Stankovic, Martin Haardt. Generalized Design of Multi-User MIMO Precoding Mateices. IEEE Wireless Communications, Vol:7, No:3, MARCH 2008
[34] Christoph Windpassinger, Robert F. H. Fischer, Johannes B. Huber. Lattice-Reduction-Aided Broadcast Precoding. IEEE Communications, Vol:52, No:12, DECEMBER 2004
[35]闫晓鹏. MIMO系统中的信号检测与预编码技术研究. [硕士论文],北京:北京邮电大学,2007
[36] F. Keskin, J. Hahn, P. W. Baier. Minimum energy soft precoding. IEEE Electronics Letters, Vol:43, No:6, MARCH 2007
[37] Chunyan Gao, Mihai Enescu, Xiao Guang Che. On the Feasibility of SVD-Based Downlink Precoding in future TDD system. IEEE Personal Indoor and Mobile Radio Communications, 2007,4394635:1-5
[38] Yang Xu, Tho Le-Ngoc. Optimal Power Allocation with Channel Inversion Regularization-Based Precoding for MIMO Broadcast Channels. EURASIO Journal on Advances in Signal Processing, 2008
[39]张齐治,朱旭明,易清明,李健,黄元.移动通信中MQAM调制方式的优化选择——瑞利衰落信道中MQAM传输误码性能的分析.无线电工程,Vol.32, No.2, 2002
[40] Weihua Zhuang, W. Vincent Huang. IEEE Vehicular Technology, Vol:46, No:1, FEBRUARY 1997
[41] Michael Joham, Hans Brunner, Raphael Hunger, David A. Schmidt, Wolfgang Utschick. Point-to-Point MIMO MMSE Vector Precoding and THP Achieving Capacity. IEEE Acoustics Speech and Signal Processing, 1-4244-1484-9/08, 2008
[42] Hamid Farmanbar, Amir K. Khandani. Precoding for the AWGN Channel With Discrete Interference. IEEE Information Theory, Vol:55, No:9, SEPTEMBER 2009
[43]杨鹏,葛建华.多输入多输出系统下低复杂度的自适应预编码方法.西安交通大学学报. Vol.41, No.4, Apr.2007
[44] Yongming Huang, Luxi Yang, Mats Bengtsson, Bjorn Ottersten. A Codebook-Based Precoding for Dual-hop Downlink with MIMO Amplify-and-Forward Relaying. IEEE Signal Processing Advances in Wireless Communication, 2009:245-249
[45]郑贱平. MIMO通信系统中的信号检测与预编码技术研究. [博士论文],西安:西安电子科技大学,2008