Outage performance of NOMA with Alamouti/MRC in dual-hop energy harvesting relay networks

This paper presents outage performance of Alamouti coding/maximum ratio combining (Alamouti/MRC) scheme in dual-hop non-orthogonal multiple access network taking advantage of simultaneous wireless information and power transfer (SWIPT). In the considered system, a base station simultaneously serves multiple users via energy harvesting enabled amplify-and-forward relay by exploiting Alamouti coding, and the users employ MRC technique. Thereby, not only spatial diversity is exploited but also channel state information burden can be reduced in terms of transmit diversity, in addition to increasing energy efficiency by SWIPT. Exact outage probability for any user is obtained over Nakagami-m fading channels by considering the channel estimation error (CEE), together with asymptotic expression providing more valuable insights. Besides, the sum throughput and energy efficiency are also investigated to characterize the system performance. Finally, the analytical results are verified by the Monte Carlo simulations. Results show that a variety of trade-off cases arise for optimum performance.