Ergodic and Bit Error Rate Performance of NOMA Over Rayleigh Fading Channel

Non-orthogonal multiple access (NOMA) is a key technology for fifth generation (5G) and beyond 5G (B5G) wireless networks to meet a wide range of needs, such as low latency, high reliability, massive connectivity, better user fairness, high throughput, and more.( In a NOMA system, most crucial function at the transmitter is power allocation (PA) followed by superposition coding (SC) and at the receiver end successive interference cancellation (SIC). This paper comprehensively surveys the recent progress of NOMA in 5G systems, reviewing the different power allocation (PA) strategies, and user pairing (UP) schemes in NOMA. The overall system throughput and performance of the system depends on user clustering (UC), PA scheme and SIC at receiver, which is expected to have minimal error or assumed to be perfect. In this paper, an analytical framework is developed over AWGN/Rayleigh fading channel and validated through MATLAB based simulations. The system model considered here is a simple two users uplink/downlink scenario for the simplicity of analysis. we also investigate the performance measures for NOMA based wireless networks under both uplink and downlink systems, such as the sum rate, Ergodic sum rate (ESR) and bit error rate (BER) expressions for a two user downlink/uplink power domain (PD)-NOMA systems over AWGN/Rayleigh fading channels.

KEYWORDS: Orthogonal Multiple Access, Non-orthogonal Multiple Access, Power-domain, Power Allocation, User Clustering, Throughput, Sum Rate, Rayleigh fading channels.