AODV-Inspired Low-Overhead Routing for Underwater Drone Swarms Using Acoustic Communication

Underwater acoustic networks are critical for applications such as environmental monitoring, infrastructure inspection, and autonomous underwater operations. In these scenarios, autonomous underwater vehicles (AUVs) increasingly operate in cooperative swarms, requiring efficient route-discovery and multi-hop communication. However, acoustic underwater communication imposes extremely constrained conditions, including low data rates, long propagation delays, limited bandwidth, and unstable channels. These constraints make routing overhead a dominant factor limiting network performance. In this work, we propose a systematic redesign of the Ad hoc On-Demand Distance Vector Routing (AODV) protocol tailored for ultra-low-rate underwater acoustic networks. The proposed approach combines three complementary design strategies: (i) architectural simplification through a layer-2 AODV variant that eliminates layer-3 overhead, (ii) protocol-level compression using the Static Context Header Compression and Fragmentation (SCHC) standard to minimize packet size, and (iii) acoustic channel-aware parameter tuning to account for long propagation delays and limited channel capacity. The approaches are designed and implemented in ns-3.43 using the underwater acoustic network (UAN) model and evaluated under reachability and scalability scenarios against the default AODV protocol. The results show that the proposed protocols reduce the hello message loss percentage from over 10% to below 3%, decrease route creation time from around 35s to around 15s, and significantly improve the packet delivery ratio under increasing traffic load. In high-load scenarios, the proposed methods consistently outperform default AODV due to reduced channel occupancy and lower collision probability.