Energy Efficient Cooperative Edge Computing with Multi-Source Multi-Relay Devices
Mianyang Yao, Long Chen, Tonglai Liu, Jigang Wu · 2019
As the extension of cloud computing, multi-access edge computing (MEC) can better support applications to accomplish larger tasks. Existing works on energy optimization of MEC systems fail to utilize multi-relay diversity, which plays a vital role to reduce the computing power consumption of mobile devices by leveraging different offloading modes. In this paper, we propose a novel computing architecture with multi-source, multi-relay, and a single edge server in an orthogonal frequency division multiplexing access (OFDMA) wireless network. The application task on a mobile device can be calculated locally, offloaded to the relay device and completed on the relay device, offloaded to the edge server directly or via a relay device with cooperative communication and executed in the edge server. The two optimization targets are total energy consumption minimization problem, and maximum energy consumption per source-relay pair devices minimization problem. For the first sub-problem, we design an optimal total energy consumption algorithm (OTCA) based on bipartite matching. The optimal energy consumption assignment algorithm (OECAA) is designed for the second sub-problem with an approximation ratio of (1+ε). Extensive simulation results show that OTCA outperforms random algorithm by 53.14% on the reduction of total energy consumption, and algorithm OECAA outperforms OTCA by 30.58% on the reduction of maximum energy consumption per source-relay pair devices.