Joint Frequency Offset and Channel Estimation for Two-way Relays in the Presence of Timing Offsets

This work explores amplify-and-forward (AF) two-way relay networks (TWRNs) working under flat-fading non-reciprocal channels conditions in the presence of both timing and frequency offsets. We showcase a novel pilot-based maximum likelihood estimator for the joint channel and carrier frequency offsets (CFOs), assuming the timing offsets are known. The proposed estimator has reasonable complexity, and we show that it meets the Cramer-Rao bound (CRB) for our model.