A novel interim channel estimation technique for MIMO mimicking AF cooperative relay systems

This paper models a generic two hop amplify and forward (AF) cooperative relay system into a multi input multi output (MIMO) mimicking (MM) AF system, to facilitate the estimation of interim relay channels at destination node (DN) without introducing complexity at relay node (RN). This is achieved through the use of predefined pilot enhancement matrix (PEM) at RN and the corresponding overall channel estimation performed at the destination node (DN) with the help of pilots broad casted from source node (SN). The proposed channel estimation algorithm is based on linear least square estimation (LSE) technique and an AF cooperative system with space time coding (STC) is considered. The proposed technique is shown to achieve a better BER performance without compromising the transmission rate. The performance advantages of this new method are substantiated through simulation studies.