It is shown that the Multi-Address Interference (MAI) can be effectively reduced when Double Waveforms (DW) are used with chip code in the asynchronous DS-CDMA system. A novel method to reduce the MAI based on Waveform Sets (WS) is proposed. For any number of users, each user can choose single waveform from the WS that can be designed with only two or three kinds of seven conventional waveforms, and can obtain better Signal to Interference plus Noise Ratio (SINR) and Bit Error Rate (BER) performance than DW method. The analytical expression of SINR at the output of each correlation receiver for the proposed method is given. Besides, the BER by Improved Gaussian Approximation (IGA) over an additive white Gaussian noise channel is derived. Relative to the existing DW method, it is shown that the proposed method can further improve the SINR and BER performance through theoretical analysis and simulation results. The overlap between simulation curves and theoretical BER curves with IGA proves that the accuracy of BER with IGA outweighs BER with Gaussian approximation (GA).
郭黎利,李清伟,董雪. 一种基于波形集设计的降低异步DS-CDMA系统多址干扰的新方法[J]. 电子与信息学报, 2017, 39(7): 1681-1687.
GUO Lili, LI Qingwei, DONG Xue. A Novel Method to Reduce the Multi-address Interference for Asynchronous DS-CDMA System Based on Waveform-sets Designing. JEIT, 2017, 39(7): 1681-1687.
WANG H F, UENG F B, and CHANG J C. Joint detection for OFDM-CDMA communications in multipath fading channels[J]. International Journal of Electronics and Communications (AEÜ), 2010, 64(2): 152-162.
[2]
JIAO B L, MA M, and LEE W C Y. A combination of CS-CDMA and OFDM for enhanced LTE on downlink channel[J]. Journal of Communications and Networks, 2013, 15(1): 8-14. doi: 10.1109/JCN.2013.000004.
[3]
PAN P, ZHANG Y G, SUN Y Q, et al. On the asymptotic spectral efficiency of uplink MIMO-CDMA systems over rayleigh fading channels with arbitrary spatial correlation[J]. IEEE Transactions on Vehicular Technology, 2013, 62(2): 679-691. doi: 10.1109/TVT.2012.2227344.
[4]
SUN S Y, CHEN H H, and MENG W X. A survey on complementary-coded MIMO CDMA wireless communications[J]. IEEE Communications Surveys Tutorials, 2015, 17(1): 52-69.
[5]
WANG H X, YAO Y D, WANG R, et al. Coordinated jamming and communications in an MC-CDMA system[J]. IEEE Transactions on Aerospace and Electronic Systems, 2015, 51(4): 3151-3160. doi: 10.1109/TAES.2015.140874.
[6]
JASBI F and SO D K C. Hybrid overlay/underlay cognitive radio network with MC-CDMA[J]. IEEE Transactions on Vehicular Technology, 2016, 65(4): 2038-2047. doi: 10.1109/ TVT.2015.2417195.
[7]
LUO T, PASUPATHY S, and SOUSA E S. Interference control and chip waveform Design in Multirate DS-CDMA Communication Systems[J]. IEEE Transactions on Wireless Communications, 2002, 1(1): 56-66.
CAO Y W and CHEN Z Q. Analysis and performance for DS/ SSMA communication system with different Chips wave [J].Journal on Communications, 2000, 21(7): 22-27.
[9]
NGUYEN H H. An improved design of chip waveforms for band-limited DS-CDMA systems[J]. IEEE Transactions on Vehicular Technology, 2004, 53(5): 1379-1386. doi: 10.1109/ TVT.2004.832381
[10]
COTTATELLUCCI L, MULLER R, and DEBBAH M. Asynchronous CDMA systems with random spreading—Part I: fundamental limits[J]. IEEE Transactions on Information Theory, 2010, 56(4): 1477-1497. doi: 10.1109/TIT.2010. 2040890.
[11]
CHIEN F T, HWANG H, and KUO C C J. Performance analysis of multicarrier CDMA systems with frequency offsets and random spreading under optimum combining[J]. IEEE Transactions on Wireless Communications, 2006, 54(4): 737-747. doi: 10.1109/TCOMM.2006.873094.
[12]
NGUYEN H H and SHWEDYK E. Double chip waveforms for asynchronous DS-CDMA systems with random signature sequences[J]. IEE Proceedings Communications, 2004, 151(4): 364-374. doi: 10.1049/ip-com:20040524.