Performance of Joint User Cooperation Diversity and Successive Interference Cancellation for CDMA

In this paper, we propose a new approach of providing diversity in uplink CDMA with practical multiuser interference environments, by employing a joint scheme consisting of user cooperation transmitter diversity and a successive interference cancellation (SIC) at the base station receiver. Under the proposed cooperation scheme, in the first signal period the users broadcast their data using their own spreading sequences, and in the second period their partners receiving the broadcasted signals, forward the detected data with the users spreading sequences. The new SIC receiver removes the multiple access inference (MAI) in serial manner and also combines signals from the desired cooperating users for data detection. Bit error simulation results are shown which confirm that under all user cooperation conditions the proposed joint Cooperative SIC offers significant improvement in the error performance compared to a SIC without cooperation under various system load and near-far channel conditions.