Linear and Nonlinear Multi-User Detection in Coded OFDM-CDMA Systems

Author: V. Kühn
Abstract: This paper analyzes the performance of linear and nonlinear multi-user detection (MUD) for an asynchronous OFDM-CDMA uplink transmission. Specifically, we regard linear MUD techniques such as the decorrelator and the MMSE approach as well as the nonlinear parallel interference cancellation (PIC) and their combination. It is pointed out that OFDM-CDMA systems offer a great advantage over single carrier systems due to flat fading conditions on each subcarrier leading to much lower implementation costs of MUD techniques. Assuming perfectly known channel impulse responses for each user and a rough synchronization it turns out that solely linear interference cancellation is not able to reach the performance of a single user system. The nonlinear parallel interference cancellation is able to totally remove the interference even for a spectral efficiency that equals that of TDMA and FDMA systems. Furthermore, the combination of linear MMSE equalization and PIC shows excellent performance even for twice as high system loads.
Document type: Conference Paper
Publication: Bucharest, Romania, 11. - 14. July 2001
Conference: International Conference on Telecommunications (ICC 01)
Volume: 5
Index: 109
ICC_2001_kühn.pdf129 KBICC_2001_kü KB
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