Based on the results in Figure 3, how does APID maintain a high packet delivery rate (PDR) as node density increases, and what specific features contribute to its superiority over GPSR and OLSR?
APID maintains a high packet delivery rate as node density increases by combining several adaptive features that traditional protocols lack. Unlike GPSR, which selects forwarders based only on geographic distance, APID chooses next-hop nodes using a confidence metric that considers link stability, energy level, and information freshness. This results in more reliable multi-hop paths even in crowded networks. Compared to OLSR, which floods control traffic and suffers from collisions in dense networks, APID uses an adaptive beaconing mechanism that reduces unnecessary overhead and avoids congestion. APID also propagates mobility updates efficiently through its self-decision diffusion method, keeping destination information accurate without excessive flooding. Finally, its packet buffering mechanism helps overcome temporary routing voids. Together, these features allow APID to scale better with node density while maintaining stable and energy-efficient routing.
