Analysis and Optimization for Weighted Sum Rate in Energy Harvesting Cooperative NOMA Systems

We consider a cooperative non-orthogonal multiple access system with radio frequency energy harvesting, in which a user with good channel harvests energy from its received signal and serves as a decode-and-forward relay for enhancing the performance of a user with poor channel. We here aim at maximizing the weighted sum rate of the system by optimizing the power allocation coefficient used at the source and the power splitting coefficient used at the user with good channel. By exploiting the specific structure of the considered problem, we propose a low-complexity one-dimensional search algorithm, which can provide optimal solution to the problem. As a benchmark comparison, we derive analytic expressions and simple high signal-to-noise ratio (SNR) approximations of the ergodic rates achieved at the two users and their weighted sum with fixed values of the power allocation and the power splitting coefficients, from which the scaling of the weighted sum in the high SNR region is revealed. Finally, we provide representative numerical results to demonstrate the validity of our results.

Authors:
Nguyen Binh Van, Vu Quang-Doanh, Kim Kiseon

Publication type:
A1 Journal article – refereed

Place of publication:

Keywords:
Cooperative NOMA, RF-energy harvesting, weighted sum rate analysis and optimization

Published:
1 October 2018

Full citation:
Van Nguyen, B., Vu, Q., Kim, K. (2018) Analysis and Optimization for Weighted Sum Rate in Energy Harvesting Cooperative NOMA Systems. IEEE Transactions on Vehicular Technology, 67 (12), 12379-12383. doi:10.1109/TVT.2018.2873412

DOI:
https://doi.org/10.1109/TVT.2018.2873412

Read the publication here:
http://urn.fi/urn:nbn:fi-fe2019040110636