Complexity study of sphere decoding in multi-antenna systems  

作　　者：QIAN Rong-rong QI Yuan PENG Zao WANG Wen-bo 

机构地区：[1]Wireless Signal Processing and Network Lab (Key Lab of Universal Wireless Communication, Ministry of Education), Beijing University of Posts and Telecommunications, Beijing 100876, China [2]School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China

出　　处：《The Journal of China Universities of Posts and Telecommunications》2010年第3期1-5,共5页中国邮电高校学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (60572120, 60602058);the Hi-Tech Research and Development Program of China (2006AA01Z257);the National Basic Research Program of China (2007CB310602)

摘　　要：In this article a bridge between the expected complexity and performance of sphere decoding （SD） is built. The expected complexity of SD for infinite lattices is then investigated, which naturally is the upper-bound of those for all the finite lattices if given by the same channel matrix and signal noise ratio （SNR）. Such expected complexity is an important characterization of SD in multi-antenna systems, because no matter what modulation scheme is used in practice （generally it has finite constellation size） this upper-bound holds. Above bridge also leads to a new method of determining the radius for SD. The numerical results show both the real value and upper-bound of average searched number of candidates in SD for 16-QAM modulated system using the proposed sphere radius determining method. Most important of all new understandings of expected complexity of SD are given based on above mentioned theoretic analysis and numerical results.In this article a bridge between the expected complexity and performance of sphere decoding （SD） is built. The expected complexity of SD for infinite lattices is then investigated, which naturally is the upper-bound of those for all the finite lattices if given by the same channel matrix and signal noise ratio （SNR）. Such expected complexity is an important characterization of SD in multi-antenna systems, because no matter what modulation scheme is used in practice （generally it has finite constellation size） this upper-bound holds. Above bridge also leads to a new method of determining the radius for SD. The numerical results show both the real value and upper-bound of average searched number of candidates in SD for 16-QAM modulated system using the proposed sphere radius determining method. Most important of all new understandings of expected complexity of SD are given based on above mentioned theoretic analysis and numerical results.

关 键 词：MIMO sphere decoding expected complexity 

分 类 号：TN959.3[电子电信—信号与信息处理] U469.11[电子电信—信息与通信工程]