Adaptive Hello Interval Scheme for Mobile Ad Hoc Routing Protocols

In mobile ad hoc networks (MANETs), nodes get information about neighboring nodes by broadcasting and receiving hello messages. Without hello messages, it is difficult for a node to maintain link connectivity with neighboring nodes. In traditional MANETs, nodes typically broadcast hello messages at fixed intervals, which leads to two problems. If the interval is too long, the nodes are unable to update the network topology in time, which may lead to link breakage. If the interval is too short, it will cause unnecessary network overhead. Therefore, in this paper, we propose an adaptive hello interval scheme (AH) for mobile ad hoc routing protocols. In this scheme, nodes adaptively adjust hello intervals based on the density and average relative speed of neighboring nodes, the communication distance as well as their own speeds. In addition, nodes consider both the distance of the nodes as well as hello intervals while selecting relay nodes. When the source node encounters routing voids, it considers the hello interval of neighboring nodes and the angle between nodes. Simulation results show that compared with the greedy perimeter stateless routing (GPSR) and maxduration-minangle GPSR (MM-GPSR), the GPSR-AH and MM-GPSRAH improve the packet delivery rate (PDR) by approximately 51.3% and 35.5% at most, then improve throughput (THP) by approximately 71.4% and 27.2% at most.