Shared Hybrid ARQ with Incremental Redundancy (SHARQ-IR) in Overloaded MIMO Systems to support Energy-Efficient Transmissions

Multiple Input and Multiple Output is a technology through which data are transmitted over the channel through multiple antennas. However, during its deployment and implementation, some pragmatic issues arise such as interference, multipath fading and noise leading to potential packet losses and consume substantial energy. To address such issues, Hybrid ARQ transmissions provide effective means for error correction, especially in a noisy wireless channel. More often few bits in packets are found to be in error and it is unnecessary to use the entire MIMO channel for retransmission to correct these errors. Hence, this paper proposes a novel approach, i.e., Shared Hybrid ARQ (SHARQ IR) using the piggyback technique in an overloaded MIMO system where the transmitting antennas are more than the receiving antennas. Additionally, the concept of a simple retransmission method is used to transform an overloaded MIMO system into either the critically loaded or under loaded MIMO systems. Simulation results outperform the contemporary approaches through reduced BER and 20% throughput gain. Such improvements have the potential to support energy-efficient transmissions for encouraging green IoT applications.