Transceiver Design for Distributed STBC Based AF Cooperative Networks in the Presence of Timing and Frequency Offsets
In multi-relay cooperative systems, the signal at the destination is affected by impairments such as multiple channel gains, Multiple Timing Offsets (MTOs), and Multiple Carrier Frequency Offsets (MCFOs). In this paper, the authors account for all these impairments and propose a new transceiver structure at the relays and a novel receiver design at the destination in Distributed Space-Time Block Code (DSTBC) based Amplify-and-Forward (AF) cooperative networks. The Cramer-Rao lower bounds and a Least Squares (LS) estimator for the multi-parameter estimation problem are derived. In order to significantly reduce the receiver complexity at the destination, a Differential Evolution (DE) based estimation algorithm is applied and the initialization and constraints for the convergence of the proposed DE algorithm are investigated.