Joint Time and Power Allocation for Cooperative NOMA based MEC System

Abstract

This paper deals with the joint time and power allocation problem in the cooperative Non-Orthogonal Division Multiple Access (NOMA) based Mobile Edge Computing (MEC) system. We consider a basic three-node MEC system consisting of a Far User (FU), a Near User (NU), and a Base Station (BS) equipped with the MEC server. In the proposed system, the tasks of the users are divided into two parts which are executed locally and at the edge server, respectively. Moreover, the NU would help offload the FU's task together with his own through NOMA transmission. The optimization problem of joint cooperation time slots assignment and power allocation at both NU and FU is formulated to minimize the total energy consumption of users. To efficiently solve it, an algorithm is proposed through employing Lagrange duality method. Simulation results demonstrate that the proposed algorithm can outperform the existing schemes and improve the energy efficiency of the system remarkably.