Decode and Forward Relaying for SC-FDE Systems with a Multi-Antenna Relay

In this paper, a cooperative relay network consisting of a single-antenna source, a multi-antenna relay, and a multi-antenna destination is considered. The relay operates in decode-and-forward (DF) mode under frequency-selective fading. To combat intersymbol interference (ISI), single-carrier frequency-domain equalization (SC-FDE) with or without decision feedback is deployed at the relay and the destination. The equalization coefficients are obtained using minimum mean squared error (MMSE) criterion. Both equal and optimum power allocations for a constant total transmit power at the relay are considered. While, the optimum power allocation is a non-convex problem, the solution is obtained using strong duality.