Abstract
Enhancing performance of downlink MU systems is an attractive and important research for future wireless systems. The non-orthogonal multiple access (NOMA) method was proposed to improve the performance of MU systems. In order to further improve the outage probability (OP) and ergodic capacity (EC) of downlink NOMA MU systems, we propose the combination of precoding and NOMA methods, and then the OP and EC of MU systems with our novel method are derived in scenarios of perfect and imperfect successive interference cancellation (SIC) scheme. Moreover, the closed-form expression of OP and EC for both scenarios is theoretically derived and compared with Monte Carlo simulations. The results show that, the analysis method is accurate, and the proposed combining precoding and NOMA can further enhance the performance of MU systems in comparing with the original orthogonal multiple access method.
Highlights
The fifth generation (5G) wireless networks is deployed for actualizing the full potential of the Internet of Things (IoT)
The system model of downlink MU system with combination of precoding and non-orthogonal multiple access (NOMA) is presented in Figure 1, the base station (BS) is equipped with M ≥ 2 antennas and zero-forcing based precoding (ZFBP) method to serve the M user clusters, while every user has only a single antenna because of its limited size
The result of proposed method is compared to the conventional method to validate the derived theoretical analysis in both perfect and imperfect successive interference cancellation (SIC)
Summary
The fifth generation (5G) wireless networks is deployed for actualizing the full potential of the Internet of Things (IoT). Throughout the previous works, the throughput and the bandwidth efficiency of NOMA systems are improved, many billions electronic devices are provided an ultrahigh connectivity by the non-orthogonal property of NOMA technology Comparing with another multiple access method such as: sparse-code multiple access, MU shared access, pattern-division multiple access, the NOMA MU systems has a lowcomplexity [3]. We have proposed and analyzed the dual hops MU system with precoding at the first hop and NOMA at the second hop in the short paper [18], and the combination of NOMA and beamforming for downlink MU systems in [19,20] These systems were analyzed under assumption of perfect SIC, perfect channel state information (CSI), perfect beamforming, and completely decoding superposition signals. The E{·} and [X]T denote the average operator and the transpose matrix of X, respectively. fX(·) and FX(·) respectively denote the probability density function (PDF) and the cumulative distribution function (CDF)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
