A new efficient CSI signalling strategy for MMR Systems with optimal detection

Abstract

We present a new Channel State Information (CSI) signalling strategy for single- branch Mobile Multihop Relay (MMR) systems. This novel signalling strategy reduces the signalling overhead at each relay by at least 50%, and eliminates the need for channel estimation at the relays. We prove that this significant overhead reduction comes at the expense of no performance loss at all when hard Maximum Likelihood detection is carried out at the destination. Furthermore, we consider the use of our system with concatenated channel codes to carry out soft Maximum a Posteriori (MAP) detection, and show that with channel codes employed the optimum detection rule becomes prohibitively complex to implement. We propose two approximate soft MAP detection schemes to make the detection feasible for our system, and demonstrate that the performance is either almost identical or slightly degraded from the ideal case with full CSI at the destination. We demonstrate the validity of our analysis through performance simulation plots.