Sum-rate based relay selection with feedback delay for a multiple half/full-duplex two-way relaying

This paper investigates the feedback delay effects on opportunistic relay selection strategy. The investigation considers a dual-hop multiple half/full-duplex two-way wireless relaying network in the system model. The selection strategy is based on the sum-rate of user-pair and related relay terminal. According to Monte-Carlo simulation results, sum-rate based relay selection strategy achieves cooperative diversity order in high signal-to-noise regimes for half-duplex and full-duplex cases. If the loop-interference variances are chosen relatively low, sum-rate based full-duplex relay selection strategy outperforms the sum-rate based half-duplex relay selection strategy. Feedback delay does not have any effects on the system performance in low signal-to-noise regimes but it does affect the performance curves and degrades the achievable diversity order from M to 0 and causes system coding gain losses in high signal-to-noise regimes.