Tang Youxi. A column-orthogonal two dimensional spread spectrum technique [A]. 2002 IEEE International Conference on Communications, Circuits and Systems and West Sino Expositions [C]. Chengdu, China, July 2002, vol. 1: 348-352.Xing H, Rinne J. The performance analysis of a two dimensional CDMA system for frequency selective channels [A]. 1998 Global Telecommunications Conference [C]. Sydney, Australia, Nov. 1998, vol. 1: 2537-2542.Xiao L, Liang Q L. A novel MC-2D-CDMA communication systems and its detection methods [A]. 2000 IEEE International Conference on Communications [C]. New Orleans, USA, June 2000, vol. 3: 1223-1227.Cavers J K. Analysis of pilot symbol assisted modulation for Rayleigh fading channels [J].IEEE Trans. on Veh. Technol.1991, 40(11):686-693Schramm P. Analysis and optimization of pilot-channel-assisted BPSK for DS-CDMA systems [J].IEEE Trans. on Commun.1998,46(9):1122-1124Chen Jiming, Tang Youxi, Li Shaoqian. Pilot power allocation for OFDM systems [A]. 2003-Spring IEEE Vehicular Technology Conference [C]. Jeju, Korea, April 2003, vol. 2: 1283-1287.Zheng Kan, Wang WenBo, Yang DaCheng. Analysis and optimization of pilot-channel-assisted QPSK for DS-CDMA systems [A]. Proc. IEEE TENCON 2000 [C]. Kuala Lumpur, Malaysia, Sep. 2000, vol. 1: 311-315.Ana G A, Beatriz B, Miguel C. Parameter optimization and simulated performance of a DVB-T digital television broadcasting system [J].IEEE Trans. on Broadcasting.1998, 44(1):131-138Chang Mingxian, Su Y T. Performance analysis of equalized OFDM systems in Rayleigh fading [J]. IEEE Trans. on WirelessCommun., 2002, l(4): 721-732.Li Y, Cimini L J, Sollenberger R N. Robust channel estimation for OFDM systems with rapid dispersive fading channels [J].IEEE Trans. on Commun.1998, 46(7):902-914Ling F. Coherent detection with reference-symbol based channel estimation for direct sequence CDMA uplink communications [A]. 1993 IEEE Vehicular Technology Conference [C]. Seracucus, NJ, May 1993: 400-403.Proakis J G. Digital Communications [M]. 4th ed., New York: McGraw-Hill, 2001, Appendix C.