Iterative Interference Cancellation for a Coded Multicarrier Frequency-Hopping CDMA (MC-FH-CDMA) System


Department of Electrical Engineering,Sharif University of Technology


In this paper, a low complexity iterative multi-user receiver for the coded MC-FH-CDMA system, is considered, which has been introduced in [1]. The structure of the proposed receiver consists of a Multi-User Likelihood Calculator (MULC) and a bank of SISO channel decoders, one for each active user. Based on the received signal and a priori information about code bits, provided by SISO decoders in the previous iteration, MULC computes the extrinsic information of the coded symbols of active users in the form of a Log-Likelihood Ratio (LLR). This information is used by channel decoders as a priori information to compute an update of LLRs. The processing proceeds in an iterative manner, similar to the decoding of turbo codes. The performance of the proposed receiver is evaluated in AWGN channels. The numerical results show that the new receiver significantly improves system performance, compared to the conventional single user receiver.