Kalman Filter-based Channel Estimation for Amplify and Forward Relay Communications

Abstract

We propose an autoregressive model for the combined amplify and forward time-varying relay channel and derive a causal iterative channel estimation method using Kalman filter. This formulation enables us to study and compare two widely used pilot transmission strategies in terms of the channel estimation errors. We provide a single-letter formula for the power allocation between the source and relay to achieve near optimal bit error rate (BER) performance in dual-hop communications. For cooperative communications, we show that the relay speed has a significant impact on the BER performance, and hence is important to be considered in practical system design.