Wireless Powered Communications with Non-Orthogonal Multiple Access

TL;DR

This paper investigates a wireless-powered uplink system using NOMA, optimizing data rates and fairness with efficient algorithms, demonstrating significant improvements over traditional methods in throughput, fairness, and energy efficiency.

Contribution

It introduces optimal and practical algorithms for NOMA-based wireless energy harvesting systems, including a greedy algorithm for time-sharing, enhancing performance and implementation.

Findings

NOMA significantly improves throughput, fairness, and energy efficiency.

The proposed greedy algorithm converges linearly with the number of users.

Trade-offs between data rates and energy harvesting are characterized.

Abstract

We study a wireless-powered uplink communication system with non-orthogonal multiple access (NOMA), consisting of one base station and multiple energy harvesting users. More specifically, we focus on the individual data rate optimization and fairness improvement and we show that the formulated problems can be optimally and efficiently solved by either linear programming or convex optimization. In the provided analysis, two types of decoding order strategies are considered, namely fixed decoding order and time- sharing. Furthermore, we propose an efficient greedy algorithm, which is suitable for the practical implementation of the time-sharing strategy. Simulation results illustrate that the proposed scheme outperforms the baseline orthogonal multiple access scheme. More specifically, it is shown that NOMA offers a considerable improvement in throughput, fairness, and energy efficiency. Also, the dependence among system throughput, minimum individual data rate, and harvested energy is revealed, as well as an interesting trade-off between rates and energy efficiency. Finally, the convergence speed of the proposed greedy algorithm is evaluated, and it is shown that the required number of iterations is linear with respect to the number of users.