Analysis and Design of Cooperative BICM-OFDM Systems

In this paper, we propose a novel cooperative diversity scheme for wireless systems employing the combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The proposed scheme utilizes an amplify-and-forward protocol where relays are assigned to multiple groups. Relays in the same group transmit concurrently over disjoint sets of sub-carriers and relays in different groups transmit in different time slots. We derive closed-form expressions for the asymptotic worst-case pairwise error probability and the diversity gain of the proposed cooperative BICM-OFDM scheme. Based on the derived analytical results we develop design guidelines for sub-carrier allocation, relay grouping, and relay selection. Simulation results corroborate the derived analytical results and confirm the effectiveness of the developed optimization framework.