Geographic random forwarding with hybrid-ARQ for ad hoc networks with rapid sleep cycles

This paper proposes and analyzes a new cross-layer protocol for ad hoc and sensor networks that unifies the concepts of geographic random forwarding (GeRaF) and hybrid-ARQ. The protocol is given the descriptive name hybrid ARQ-based intra-cluster geographically informed relaying (HARBINGER). Like GeRaF, HARBINGER assumes that each node knows its own position and that messages are addressed by location. As is common for sensor networks, the nodes cycle on-and-off according to a sleep schedule. Unlike GeRaF, which returns to the initial transmission state If no active node is within range, the nodes in HARBINGER combine transmissions thereby achieving an additional time-diversity benefit. With HARBINGER, a lower density of active nodes achieves almost the same delay and energy efficiency as GeRaF, implying that a lower duty cycle sleep schedule could be used to prolong the useful lifetime of the network. The paper gives detailed analysis of a version of the protocol (Fast-HARBINGER) whereby the sleep states of the network are synchronized with the data packet transmission rate of the network.