Dual-Hop MIMO Amplify-and-Forward Relay Channel Capacity with Keyhole Effect

Keyhole fading present in some relay based applications can degrade the system performance. In this paper, we investigate the effect of multi-keyhole fading on the ergodic capacity of fixed infrastructure based multiple-input multiple-output (MIMO) amplify-and-forward (AF) relaying systems. Specifically, considering a Rayleigh-multi-keyhole MIMO AF relay channel, we derive an expression for the system's ergodic capacity. Our capacity expression is valid for arbitrary number of antennas, number of keyholes, keyhole power distribution and all signal-to-noise ratio values.