Estimation of Synchronization Parameters in AF Cooperative Networks
In cooperative networks, Multiple Carrier Frequency Offsets (MCFOs) and Multiple Timing Offsets (MTOs) originate due to multiple distributed nodes. In this paper, algorithms for joint estimation of these parameters and channels in amplify-and-forward (AF) relaying networks are proposed. A new training model and transceiver structure at the relays for achieving synchronization throughout the network is devised. New exact closed-form expressions for the Cramer-Rao Lower Bounds (CRLBs) for the multi-parameter estimation problem are derived. An estimation method is proposed for jointly estimating MCFOs, MTOs, and channel gains at the destination based on Space-Alternating Generalized Expectation maximization (SAGE) and compared to a computationally-intensive Least Squares (LS) approach.