NOMA-Aided Cell-Free Massive MIMO with MEC: A Trade-Off Between Latency and Energy Consumption

This paper investigates the trade-off between latency and energy consumption in a non-orthogonal multiple access (NOMA)-aided cell-free massive multiple-input multiple-output system that incorporates mobile edge computing (MEC). We focus on a scenario where multiple access points, each equipped with a single antenna and supported by an MEC server, collaboratively serve user equipment pairs using a power-domain NOMA strategy. The primary objective is to optimize overall system latency under power allocation constraints while minimizing energy consumption penalty. To tackle this non-convex optimization problem, we propose a two-step solution approach. The first step involves identifying optimal NOMA pairs, and the second step employs the successive convex approximation method to jointly optimize power allocation and offloading ratios. Numerical simulations are performed to validate the effectiveness of the proposed solution and to elucidate the trade-off between system latency and energy consumption.