Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Impact of Channel Estimation Errors on Multiuser Detection via the Replica Method | EURASIP Journal on Wireless Communications and Networking 2005 2 175-186 2005 Hindawi Publishing Corporation Impact of Channel Estimation Errors on Multiuser Detection via the Replica Method Husheng Li Department of Electrical Engineering Princeton University Princeton NJ 08544 USA Email hushengl@ H. Vincent Poor Department of Electrical Engineering Princeton University Princeton NJ 08544 USA Email poor@ Received 26 January 2005 For practical wireless DS-CDMA systems channel estimation is imperfect due to noise and interference. In this paper the impact of channel estimation errors on multiuser detection MUD is analyzed under the framework of the replica method. System performance is obtained in the large system limit for optimal MUD linear MUD and turbo MUD and is validated by numerical results for finite systems. Keywords and phrases CDMA multiuser detection replica method channel estimation. 1. INTRODUCTION Multiuser detection MUD 1 can be used to mitigate multiple access interference MAI in direct-sequence code division multiple access DS-CDMA systems thereby substantially improving the system performance compared with the conventional matched filter MF reception. The maximum likelihood ML -based optimal MUD introduced in 2 is exponentially complex in the number of users thus being difficult to implement in practical systems. Consequently various suboptimal MUD algorithms have been proposed to effect a tradeoff between performance and computational cost. For example linear processing can be applied based on zero-forcing or minimum mean square error MMSE criteria thus resulting in the decorrelator 1 and the MMSE detector 3 . For nonlinear processing a well-known approach is decision-feedback-based interference cancellation IC 1 which can be implemented in a parallel fashion PIC or successive fashion SIC . It should be noted that the above algorithms are suitable for systems without channel codes. For channel-coded CDMA systems the turbo
