Channel Estimation for Two-Way Relay Networks with Imperfect Synchronization

In this paper, the channel estimation problem for two-way relay networks with imperfect synchronization is considered where training sequences sent from the two sources can not arrive at relay simultaneously. To analyze its performance, the Cramer-Rao bound of composite channel coefficients are first derived, then the optimal power allocation is investigated aiming at minimizing the corresponding CRBs. Focusing on declining the bit error probability of signal detection at receiver, an iterative estimation algorithm is proposed based on the optimal linear estimator. Simulations are conducted to demonstrate the effectiveness of the proposed estimation algorithm.