Super-orthogonal space-time turbo transmit diversity for CDMA

作     者：van Wyk, DJ Linde, LP van Rooyen, PGW 

作者机构：RapidMobile Pty Ltd ZA-0020 Pretoria South Africa Univ Pretoria Dept Elect Elect & Comp Engn ZA-0002 Pretoria South Africa Broadcom San Diego CA 92128 USA 

出 版 物：《EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING》 (EURASIP信号处理进展杂志)

年 卷 期：2005年第2005卷第6期

页      面：861-871页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 

主　　题：transmitter diversity space-time coding code-division transmit diversity layered super-orthogonal turbo transmit diversity low-rate spreading and coding CDMA wireless communications 

摘      要：Studies have shown that transmit and receive diversity employing a combination of multiple transmit-receive antennas (given ideal channel state information (CSI) and independent fading between antenna pairs) will potentially yield maximum achievable system capacity. In this paper, the concept of a layered super-orthogonal turbo transmit diversity (SOTTD) for downlink direct-sequence code-division multiple-access (CDMA) systems is explored. This open-loop transmit diversity technique improves the downlink performance by using a small number of antenna elements at the base station and a single antenna at the handset. In the proposed technique, low-rate super-orthogonal code-spread CDMA is married with code-division transmit diversity (CDTD). At the mobile receiver, space-time (ST) RAKE CDTD processing is combined with iterative turbo code-spread decoding to yield large ST gains. The performance of the SOTTD system is compared with single- and multiantenna turbo-coded (TC) CDTD systems evaluated over a frequency-selective Rayleigh fading channel. The evaluation is done both by means of analysis and computer simulations. The performance results illustrate the superior performance of SOTTD compared to TC CDTD systems over practically the complete useful capacity range of CDMA. It is shown that the performance degradation characteristic of TC CDTD at low system loads (due to the inherent TC error floor) is alleviated by the SOTTD system.