A Noise Reduction Amplify-and-Forward Relay Protocol for Distributed Spatial Diversity

Amplify-and-forward transmission has been shown to be a viable transmission protocol for wireless networks incorporating distributed spatial diversity. A drawback of this relatively simple transmission protocol is identified. In addition to signal amplification, perpendicular noise at the relay is also amplified. A method to reduce the noise at the relay prior to amplification is proposed. To demonstrate the improvement of this protocol, we consider single-user single-relay transmission and show that by eliminating perpendicular noise at the relay, the outage region boundaries are reduced. Perpendicular noise elimination is inherent in decode-and-forward relaying. Hence, Fair comparisons of amplify-and-forward relaying with decode-and-forward relaying are based on noise reduced amplify-and-forward relaying