  Exploiting the idle computation resources of mobile devices in mobile edge
computing (MEC) system can achieve both channel diversity and computing
diversity as mobile devices can offload their computation tasks to nearby
mobile devices in addition to MEC server embedded access point (AP). In this
paper, we propose a non-orthogonal multiple-access (NOMA)-aided cooperative
computing scheme in a basic three-node MEC system consisting of a user, a
helper, and an AP. In particular, we assume that the user can simultaneously
offload data to the helper and the AP using NOMA, while the helper can locally
compute data and offload data to the AP at the same time. We study two
optimization problems, energy consumption minimization and offloading data
maximization, by joint communication and computation resource allocation of the
user and helper. We find the optimal solutions for the two non-convex problems
by some proper mathematical methods. Simulation results are presented to
demonstrate the effectiveness of the proposed schemes. Some useful insights are
provided for practical designs.
