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...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.展开更多
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)
文摘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.
