Outage probability of opportunistic decode-and-forward relaying with beamforming in two-wave with diffuse power fading channels

This paper proposes a new opportunistic decode-and-forward (DF) relaying with beamforming in multiple-input and multiple-output (MIMO) multiple relay networks. In the proposed scheme, only one relay which correctly decodes the signal from the source and has the best channel to the destination is selected. To examine the benefits of our proposed scheme in two-wave with diffuse power (TWDP) fading channels, we first derive a closed-form expression for the exact outage probability. We then derive a tight lower bound on the exact result to allow for a convenient and accurate approximation. Furthermore, we derive the asymptotic outage probability to gain valuable insights into the network behavior in the high signal-to-noise ratio (SNR) regime. We demonstrate that the diversity order is equal to the product of two parameters: 1) the number of relays and 2) the minimum number of antennas at the source and the destination. Notably, this diversity order is independent of TWDP fading parameters. The accuracy of our analytical results is validated via Monte Carlo simulations.