A low-complexity multiple signal representation scheme in downlink OFDM-CDMA  

作　　者：DAN LiLin XIAO Yue CHENG Peng WU Gang LI ShaoQian 

机构地区：[1]National Key Laboratory of Science and Technology on Communications, University of Electronic Science and Technology of China, Chengdu 610054, China

出　　处：《Science in China(Series F)》2009年第12期2433-2444,共12页中国科学（F辑英文版）

基　　金：Supported in part by DoCoMo Beijing Labs Co., Ltd., International Sci. & Tech. Cooperation Project of the Ministry of Sci. & Tech. of China(Grant No. 2008DFA11700);the National Natural Science Foundation of China (Grant Nos. 60902026, 60602008)

摘　　要：OFDM-CDMA is an attractive technique for broadband wireless communication. However, the high peakto-average power ratio （PAPR） of the downlink signals, generated from multiple spread codes, remains a serious problem. In this paper, a low-complexity multiple signal representation （MSR） scheme is proposed to control the PAPR problem in downlink OFDM-CDMA systems. The proposed scheme generates multiple candidate signals by a novel user grouping scheme, which is without distortion and can provide more PAPR reduction than the conventional MSR schemes, such as partial transmit sequence （PTS） and selective mapping （SLM）. Furthermore, a low-complexity processing structure is developed using a novel joint spreading and inverse fast Fourier transform （S-IFFT） to simplify the generation of multiple candidate signals. Complexity analysis and numerical results show that the OFDM-CDMA systems employing the proposed scheme have better tradeoff between PAPR reduction and computational complexity, compared with the conventional MSR schemes.OFDM-CDMA is an attractive technique for broadband wireless communication. However, the high peakto-average power ratio （PAPR） of the downlink signals, generated from multiple spread codes, remains a serious problem. In this paper, a low-complexity multiple signal representation （MSR） scheme is proposed to control the PAPR problem in downlink OFDM-CDMA systems. The proposed scheme generates multiple candidate signals by a novel user grouping scheme, which is without distortion and can provide more PAPR reduction than the conventional MSR schemes, such as partial transmit sequence （PTS） and selective mapping （SLM）. Furthermore, a low-complexity processing structure is developed using a novel joint spreading and inverse fast Fourier transform （S-IFFT） to simplify the generation of multiple candidate signals. Complexity analysis and numerical results show that the OFDM-CDMA systems employing the proposed scheme have better tradeoff between PAPR reduction and computational complexity, compared with the conventional MSR schemes.

关 键 词：OFDM-CDMA spread-IFFT （S-IFFT） multiple signal representation （MSR） user grouping 

分 类 号：TN929.533[电子电信—通信与信息系统] TN929.5[电子电信—信息与通信工程]