MIMO multi-hop relay systems

Multiple Input Multiple Output (MIMO) systems use multiple transmit and receive antennas to achieve higher data rates by transmitting multiple independent data systems. Transmission errors can be reduced by using Hybrid Automatic Repeat request (HARQ) combining techniques with MIMO systems. In this thesis, the use of HARQ for MIMO multi-hop communication is studied. We propose two MIMO HARQ combining methods which are based on using pre-combiningonly and a joint pre and post combining techniques. In addition to conventional single-hop transmission, HARQ schemes for MIMO multi-hop relay systems are also investigated. A novel approach is proposed to deal with the parallel HARQ processes in MIMO relay scenario. An information theoretic throughput analysis is performed to evaluate the performance of the relay system by employing various transmission techniques for relay-destination link. Evaluation is carried out on the delay involved while employing the relay systems as compared to single hop systems. Simulation results show that the proposed system can enhance the overall throughput performance of MIMO single-hop and multi-hop relay systems. Considering the recent research interest in green radio and requirements of reduced energy consumption by the wireless networks, we evaluated the energy efficiency of existing and proposed MIMO HARQ techniques for sensor and cellular networks. The results show that the proposed scheme is more energy efficient compared to other schemes in single-hop as well as multi-hop scenarios.EThOS - Electronic Theses Online ServiceGBUnited Kingdo