BER-Minimized Power Allocation for QR-Based Successive Detection in MIMO Wireless Communications

• Main Authors: Jie-Gang Kuang, 匡劼剛
• Other Authors: Ta-Sung Lee
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/256ak8

碩士 === 國立交通大學 === 電信工程系所 === 96 === It is well known that spatial multiplexing and transmit diversity are popular techniques in modern wireless communications. In this thesis, we first propose a BER-minimized power allocation strategy for spatial multiplexing systems over i.i.d. Rayleigh fading channels based on the QR-based successive detection scheme. With the knowledge of distribution of QR decomposition in spatial multiplexing, the design criterion for power loading is the overall BER averaged with respect to the channel distribution. Based on the closed-form solution, the optimal power allocation scheme is proposed, which aims to minimize the overall average BER performance of spatial multiplexing systems at medium-to-high SNR. Afterwards, with the distribution of the R matrix of QR decomposition for DSTTD systems, the design procedure of the power allocation scheme proposed for spatial multiplexing systems can be applied to DSTTD systems. Although parts of the distribution of the R matrix in DSTTD are merely approximations, the estimated average BERs are quite accurate. The power allocation scheme adapted for DSTTD systems are shown to be also effective at the high SNR regime by numerical simulations. Moreover, the proposed scheme can be further extended to multiple STTD systems