Fast and Energy Efficient Multihop D2D Routing Scheme

Device-to-device (D2D) communications are expected to offload cellular networks and enhance public safety. In addition to the capability of direct communication between devices, the capability of delivering data over multihops in an ad hoc manner by autonomous decision of each device is highly desired to expand application areas of D2D communications. To address this issue, we propose a fast and energy efficient D2D multihop routing method using the geographic locations of nodes. To expedite data delivery while saving transmission powers of nodes, we devise the next hop selection method considering the congestion levels of potential next hops. In addition, we devise a detour scheme to move around a routing hole that is encountered when a node cannot find a neighbor that is closer to the destination of a packet than itself. We also propose management procedures so that each node acquires the locations of destinations and its neighboring nodes. Through extensive simulations, we validate the proposed method by comparing the performance of the proposed method with those of maximum progress method (MaxP), cost over progress method (CoP), and congestion-aware forwarder selection method (CAFS). Even though the number of hops obtained by the proposed method is larger than those obtained by MaxP and CAFS, our method is superior to them in terms of the probability of successfully delivering packets to destinations and total amount of energy consumption. We also show that our method can reduce end-to-end delay considerably compared with CoP.