Bandwidth Efficient Channel Coding Scheme for Non-cooperative Overloaded Multiuser MIMO Systems

Abstract:
Multiple Input Multiple Output (MIMO) system provides the high data transmission with spectral efficiency under Orthogonal Frequency Division Multiplexing (OFDM). Multiuser detection becomes complex when there exists a large number of non-cooperative co-channel users in the system. In this scenario, it is difficult to accommodate each user with a separate physical antenna at a receiver. It leads the MIMO-OFDM system to an overloaded condition, where Multi-User Detection (MUD) becomes a challenging problem. In this article, we design an efficient receiver that reduces the complexity of an overloaded MIMO-OFDM system with the efficient MUD. In order to achieve the proficient outcomes, Chase Combining Hybrid Automatic Repeat Request (CC-HARQ) protocol is used for the re-transmissions in the receiver to create virtual antennas, which converts an overloaded system into an underloaded or a critically loaded system. Using this technique, the suboptimal detection algorithms can be applied in an overloaded condition. The significant performance improvements in terms of throughput, low Bit Error Rate (BER) and Packet Drop Rate (PDR) are computed analytically and presented through MATLAB simulations.