Column Permutation of Channel Matrix for Complexity Reduction of Sphere Decoding in LTE

• Main Authors: Yao-Hsien Chuang, 莊耀賢
• Other Authors: Hung-Ta Pai
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/73931746140740382905

碩士 === 國立臺北大學 === 通訊工程研究所 === 99 === The MIMO system is an important part of wireless communication system. At the receiver, it is necessary to develop an algorithm to detect transmitted signals. The maximum-likelihood (ML) algorithm is optimal but its complexity is very high and increases as the number of antennas and modulation symbols. Error performance of sphere decoding may be optimalor near-optimal based on the ML criterion. Although the computational complexity for the sphere decoding is lower than a full search algorithm, it is still higher than suboptimal algorithms. Therefore, it is our goal to reduce the computational complexity of the sphere decoding. The QR decomposition is a well-known technique to reduce the complexity of the MIMO detection. It is also applied to the sphere decoding algorithm. Although the computational complexity of the sphere decoding algorithm is decreased through the sorted QR decomposition, it is noticeable that the sorted QR decomposition is not designed for the sphere decoding originally. In this study, we propose an efficient permutation of channel matrix to reduce the computational complexity and the complexity using the proposed method is lower than the complexity using the sorted QR decomposition.Our simulations demonstrate the complexity of the proposed method in the LTE system.