Leveraging on the Impact of Imperfect Channel Estimation for MIMO Relaying Systems

In this paper, we study a multi-user multiple-input multiple-output (MIMO) dual-hop wireless relaying system, where the decode-and-forward protocol is applied at the intermediate relay node. The well-known MIMO spatial multiplexing technique is employed, where the linear yet efficient zero-forcing detection is utilized at the receiver side of each hop. The practical scenario of channel estimation errors and/or delayed channel response is embraced when the signals experience mutually independent Rayleigh fading. In oppose to the approach followed in the vast majority of the published works, in this manuscript the channel estimation error term is reckoned as a signal rather than interference or noise, which may significantly enhance the overall system performance. Analytical results involving outage probability and average symbol error rate are extracted in closed-form. Capitalizing on the above performance metrics, new engineering insights are manifested highlighting clearly the superiority of the proposed approach against the conventional one when a delayed/imperfect channel response is present.