Ergodic Sum Rate Evaluation of Cellular Multiuser Two-Way Relaying with Beamforming and Antenna Selection Over Nakagami-m Fading

In this paper, we evaluate the ergodic sum rate (ESR) performance of cellular multiuser two-way relaying networks (CMTWRNs), where a multiantenna base station (BS) exchanges information bidirectionally with one of the several single-antenna mobile stations (MSs) with the help of a single-antenna relay terminal. Specifically, we adopt two transmission schemes (i.e., beamforming (BF) and antenna selection (AS)) at the BS and user selection at MSs to maximize the end-to-end signal-to-noise ratios. Under such transmission schemes, we derive new tight closed-form ESR expressions for the CMTWRNs in the presence of Nakagami-m fading environment. Further, based on the numerical results, we conduct a comparative study between the ESR performances of the two schemes, which indicates that the AS scheme provides approximately equal ESR performance as BF. Therefore, AS scheme can be a good alternative to the BF for the CMTWRNs as it reduces the transceiver complexity and signaling cost. Finally, simulation results are presented to corroborate our theoretical findings.