Abstract
In this paper, we investigate a relay-assisted cooperative spectrum sharing for the considered non-orthogonal multiple access (NOMA) scheme in cognitive radio networks, where the relay node assists the base station (BS) to transmit the superimposed composite signal to two receivers by utilizing an amplified-and-forward (AF) technique with simultaneous wireless information and power transfer (SWIPT). The exact expressions for outage probabilities of two receivers are derived in closed forms. Moreover, a joint optimization of power allocation and the proportion of information splitting for energy harvesting is proposed in terms of energy efficiency (EE) maximization under required data reliability. Simulation results validate the analytical results since the analytical results match well with simulation results and demonstrate the performance advantages of the proposed scheme over other schemes and direct transmission.
Highlights
Non-orthogonal multiple access (NOMA) has been regarded as a promising multiple access technique for supporting massive machine-type communication scenarios due to its higher spectral efficiency for ultra-dense network deployment [1,2]
By considering the maximization of the average EE under the required transmission rates, we propose a full-search algorithm to obtain the optimal power allocation and proportion of information splitting coefficients, which provides a practical guideline that the optimized coefficients enable the proposed protocol to achieve a better performance of EE compared with other scheme and direct transmission
We compare the proposed spectrum sharing scheme with other schemes based on underlay cognitive radio (CR) networks with simultaneous wireless information and power transfer (SWIPT) [17] and direct transmission
Summary
Non-orthogonal multiple access (NOMA) has been regarded as a promising multiple access technique for supporting massive machine-type communication scenarios due to its higher spectral efficiency for ultra-dense network deployment [1,2]. The NOMA scheme is based on assigning higher power to users with worse channel conditions, which will lead the users in cell-edge to get more energy. Unlike conventional orthogonal multiple access (OMA) scheme, NOMA techniques can effectively utilize same resource blocks such as time, frequency, and power, to implement multiple-access applications, which could effectively improve the system transmission performance [3]. NOMA can provide massive connectivity, low latency, as well as high spectral efficiency and reliability compared to OMA. The inter-cell interference is more severe in NOMA compared to OMA due to biased power allocation toward users in cell-edge.
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
