Bison : A Binary Sparse Network Coding based Contents Sharing Scheme for D2D-Enabled Mobile Edge Caching Network

Mobile edge caching network (MEN), which enables popular or reusable content caching and sharing among adjacent mobile edge devices, has become a promising solution to reduce the traffic and burden over backhaul links. Network coding (NC), represented by classical random linear network coding (RLNC), is utilized to facilitate content delivery and increase throughput in MEN. However, as the harsh decoding condition results in unacceptable time and storage overhead, classical RLNC schemes struggle to be widely deployed in practice. In this work, we propose a cost-effective NC-based content-sharing scheme based on binary sparse network coding (BSNC), called Bison, for D2D-enabled MEN. Based on the shared relationship between the binary sparse coded block (BSCB), Bison first designs a caching maintenance module to characterize the sharing progress and maintain the caching state of each edge node. Then, Bison defines a matching metric named neighbor utility to evaluate neighbors' matching values by considering nodes' demand and content decodability. Guiding by the metric, Bison achieves the most beneficial matching relationship among edge nodes through a proposed online matching policy. Finally, Bison devises a coded block delivery strategy to enable the sharing of valuable content between two matched edge nodes. Extensive experiments in simulations and real-world Android testbeds demonstrate its effectiveness and efficiency, wherein Bison is at least 30% less than the RLNC-based scheme on time consumption and at least 10% less than the classical BSNC-based scheme on storage overhead. The results also show that our matching policy and coded block delivery strategy can perform with a low response latency on edge and mobile devices.