Semi-Blind Channel Estimation for Space-Time Coded Amplify-and-Forward Relay Networks

In this paper, we propose a semi-blind channel estimation algorithm for amplify-and-forward (AF) relay networks. The algorithm fits well for the recently developed space-time coding (STC) technique in AF relay network that serves for small size terminal and achieve the transmission diversity. Compared to the optimal training based estimators, e.g., maximum likelihood (ML) or linear minimum mean square (MMSE), the proposed semi-blind approach requires less training for successful channel estimation, or it yields better estimates if the same amount of training is used. The channel ambiguity issue as well as its relationship with the traditional semi-blind method is discussed in detail. We then provide various numerical examples to corroborate the proposed studies.