Multiple Access Partial Computational Offloading: Two-User Case

The opportunity to offload computational tasks to computing resources embedded in the network infrastructure enables mobile users to expand the scope of the applications that can be processed and to reduce the energy required to complete them. In this paper we seek insight into the impact of the choice of the multiple access scheme that is employed when each of two users has a divisible task that they wish to complete with partial assistance from a computing resource at the access point. In particular, we obtain quasi-closed-form solutions for the partitioning of the problem, the transmission powers and the transmission rates that minimize the sum of the transmission energy and the local computation energy for each user, subject to latency, transmission power and achievable rate constraints. We consider both the case in which the multiple access scheme is unrestricted, and the case of time division multiple access. Our numerical results demonstrate that exploiting the full capabilities of the multiple access channel enables a substantial reduction in the energy expended by the users, especially when the users have significantly different channel gains.