Dual-Hop Amplify-and-Forward MIMO Relaying with Antenna Selection in Nakagami-m Fading

In this contribution, we propose an antenna selection scheme in dual-hop amplify-and-forward (AaF) multiple-input multiple-output (MIMO) relaying in Nakagami-m fading channels. In each hop, the transmit and receive antenna pair that maximizes the instantaneous signal-to-noise ratio (SNR) at the receiver is selected for transmission. We derive new closed-form expressions for the exact outage probability and the exact symbol error rate (SER), relying on the cumulative distribution function (CDF) of the instantaneous end-to-end SNR. Furthermore, we derive simple closed-form expressions for the asymptotic outage probability and the asymptotic SER, revealing the diversity order of the proposed scheme. Specifically, the diversity order is equal to the minimum of two parameters: first, the product of the number of source and relay antennas and the first hop fading parameter, and second, the product of the number of relay and destination antennas and the second hop fading parameter. Our derived results apply to general operating scenarios with distinct Nakagami-m fading parameters and average SNRs in each hop.