A Novel DST-based Packet Combining Scheme for MIMO-HARQ Systems

This paper proposes a novel receiver scheme for multiple-input multiple-output (MIMO) systems with hybrid automatic-retransmission-request (HARQ) mechanism. The scheme is based upon Dempster-Shafer evidence theory (DST), and improves the decoding performance by characterizing the uncertainty contained in the received signals. In addition, the new scheme can further counteract the uncertainty of the soft decisions by combining multiple soft information sources. Furthermore, it can make full use of the received signals and performs especially well when the transmitted signal is nonuniformly distributed, as compared with the maximum-likelihood (ML) approach. This paper analyzes the proposed scheme and its counterparts in terms of two key design factors: decoding performance and the complexity imposed. Simulation results under IEEE 802.16e setting with UMTS channel model demonstrate that the proposed receiver scheme with low complexity outperforms the ML approach, and reaps much more performance gain with only moderate complexity increase over the other suboptimal receiver schemes. The simulations show a good agreement with the performance analysis of the combining schemes.