Optimal Design of Resource Element Mapping for Sparse Spreading Non-Orthogonal Multiple Access

• Published in: IEEE wireless communications letters Vol. 7; no. 5; pp. 744 - 747
• Main Authors: Yu, Hanxiao, Fei, Zesong, Yang, Nan, Ye, Neng
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.10.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Complexity theory; Computational geometry; Convexity; Iterative algorithms; Mapping; Mathematical programming; NOMA; Non-orthogonal multiple access; Nonorthogonal multiple access; optimal sparsity; Optimization; Programming; resource element mapping; Resource management; Spreading; sum-rate maximization; Two dimensional displays
• ISSN: 2162-2337; 2162-2345
• DOI: 10.1109/LWC.2018.2818157

We propose a new design of the optimal resource element (RE) mapping patterns to maximize the sum-rate of a sparse spreading non-orthogonal multiple access system. In this system, the grouped users who use the same radio resource have different channel conditions. First, we formulate a sum-rate optimization problem subject to sparsity and power constraints. To solve this non-trivial optimization problem, we transform it to an equivalent penalized problem by deriving the closed-form penalty parameters. We then convert this problem to a sequence of subproblems using the difference of convex programming and propose an efficient algorithm to find the optimal solution. Numerical results demonstrate that the proposed algorithm achieves a higher sum-rate and a superior block error rate performance than the conventional RE mapping schemes.