Energy-Efficient Resource Allocation for Downlink Non-Orthogonal Multiple Access Network

• Published in: IEEE transactions on communications Vol. 64; no. 9; pp. 3722 - 3732
• Main Authors: Fang Fang, Haijun Zhang, Julian Cheng, Leung, Victor C. M.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-09-2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Difference of convex; Downlink; Energy efficiency; Mobile communication; Multiplexing; NOMA; non-orthogonal multiple access; orthogonal frequency division multiple access; Receivers; resource allocation; Resource management; Silicon carbide; successive interference cancellation
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2016.2594759

Non-orthogonal multiple access (NOMA) is a promising technique for the fifth generation mobile communication due to its high spectral efficiency. By applying superposition coding and successive interference cancellation techniques at the receiver, multiple users can be multiplexed on the same subchannel in NOMA systems. Previous works focus on subchannel assignment and power allocation to achieve the maximization of sum rate; however, the energy-efficient resource allocation problem has not been well studied for NOMA systems. In this paper, we aim to optimize subchannel assignment and power allocation to maximize the energy efficiency for the downlink NOMA network. Assuming perfect knowledge of the channel state information at base station, we propose a low-complexity suboptimal algorithm, which includes energy-efficient subchannel assignment and power proportional factors determination for subchannel multiplexed users. We also propose a novel power allocation across subchannels to further maximize energy efficiency. Since both optimization problems are non-convex, difference of convex programming is used to transform and approximate the original non-convex problems to convex optimization problems. Solutions to the resulting optimization problems can be obtained by solving the convex sub-problems iteratively. Simulation results show that the NOMA system equipped with the proposed algorithms yields much better sum rate and energy efficiency performance than the conventional orthogonal frequency division multiple access scheme.