Ergodic capacity analysis of full-duplex amplify-forward MIMO relay channel using Tracy-Widom distribution

In this paper, we explore the use of full-duplex technique to improve spectrum efficiency in amplify-forward multiple-input multiple-output (MIMO) relay channel. The full-duplex operation can reduce the overall communication to only one phase but suffers from self-interference. We investigate an asymptotic ergodic capacity of full-duplex amplify-forward MIMO relay using Tracy-Widom distribution. Instead of using numerical solution, we derive an asymptotic expression of ergodic capacity by exploiting eigenvalue distributions. We consider singular value decomposition (SVD) based scheme with perfect channel state information (CSI) with three scenarios: i) Large relay, and fixed source and destination antennas, ii) Fixed source, and large relay and destination antennas, and iii) Large relay and source, and fixed destination antennas. We show the simulation results that the capacity of full-duplex model is almost twice the capacity of half-duplex. We show that increasing the number of destination antennas does not help much for improving the capacity when the number of source antennas is fixed. Moreover, we also show that increasing the number of source antennas can decrease the capacity when the number of destination antennas is fixed.