Signal Detection for Amplify-and-Forward Relay Networks With Imperfect Channel Estimation

We consider signal detection in amplify-and forward wireless relay networks when we have an imperfect partial channel estimate available at the destination. Channel state information is required when coherent distributed space-time coding is employed at the relays. For the case of maximum a posteriori signal detection, we propose a modified detector formulation that takes the variance of channel estimation errors into account. Although the proposed modification is based on some simplifying assumptions on the distribution of the channel and the noise, we show that it permits a considerable performance improvement, without, however, increasing the receiver's complexity. We consider the case of two relays with Alamouti space-time coding as case study.