Joint offloading and beamforming design in full‐duplex multi‐hop SWIPT MEC systems under non‐linear energy harvesting model

Abstract

Abstract In Internet of Things scenarios, the problem of restricted energy and limited computation capability of user node usually exists. To address the problem, a multiple‐input‐multiple‐output full‐duplex multi‐hop relay simultaneous wireless information and power transfer (SWIPT) mobile‐edge computing (MEC) system is proposed in this paper, where energy harvesting model is non‐linear. With the aid of MEC and SWIPT, user node equipped with power splitting receiver can locally execute computation tasks or offload partial or all of it to access point associated with an MEC server by using its battery energy, and harvest energy to replenish its battery while downloading the computation results. In addition, the system introduces full‐duplex multi‐hop relay and non‐linear energy model to improve network coverage and model practical energy harvesting circuit. Aiming at minimising the system energy consumption, an energy efficient optimisation problem is formulated while satisfying the latency and energy constraints. Since the original problem is non‐linear and non‐convex, it is converted into two subproblems and successive convex approximation‐based algorithm and geometric programming‐based algorithm based alternating optimisation technique are adopted to solve them. Numerical results verify the superiority of the proposed optimisation scheme compared with other benchmark schemes.