Performance Analysis of Fixed Gain Amplify-and-Forward Relaying with Time-Efficient Cascaded Channel Estimation
In a cooperative system with an Amplify-and-Forward relay, the cascaded channel training protocol enables the destination to estimate the source-destination channel gain and the product of the Source-Relay (SR) and Relay-Destination (RD) channel gains using only two pilot transmissions from the source. Notably, the destination does not require a separate estimate of the SR channel. The authors develop a new expression for the Symbol Error Probability (SEP) of AF relaying when imperfect Channel State Information (CSI) is acquired using the above training protocol. A tight SEP upper bound is also derived; it shows that full diversity is achieved, albeit at a high Signal-to-Noise Ratio (SNR).