Energy-Efficient Path-Loss-based Self-Organized Power Level Selection for GF-NOMA in mMTC.

This paper proposes a path-loss-based self-organized power resource selection method to suppress energy consumption in the grant-free power-domain non-orthogonal multiple access (GF-NOMA) for the massive machine-type communications. The proposed method uses a taxis model, which autonomously controls a swarm by virtual forces, i.e., attraction and repulsion. First, the proposed method is based on the path-loss value of each terminal to suppress its energy consumption. For example, the proposed method repels each terminal with a larger path-loss value, including line-of-sight (LoS) and non-LoS (NLoS), from a lower-power resource. Second, the proposed method attracts each terminal to a more vacant resource to provide sufficiently high throughput for existing methods. Our simulation results highlighted that the proposed method achieved 80% lower energy than an existing method that uses distances from the connected base station while providing similar throughput.