Adaptive Redundancy and WuRX-Assisted Forwarding in Batteryless Multi-Hop Networks

Abstract

Conventional wireless sensor networks are typically battery-powered, which limits long-term deployment when batteries cannot be replaced easily in harsh or inaccessible environments. Energy-harvesting wireless sensor networks reduce this burden, but rechargeable batteries still degrade over repeated charge cycles and eventually create disposal burden. Batteryless nodes avoid battery replacement by using capacitive storage, but they still face frequent brownouts and only a limited set of multi- hop communication protocols has been studied for this regime. To address this gap, this thesis proposes and evaluates WARP-EH, a new intermittent multi-hop forwarding protocol for batteryless energy-harvesting wireless sensor networks. WARP- EH combines capacitor-threshold node operation to avoid futile transmissions at low stored energy, wake-up-radio rendezvous to reduce idle listening, bounded store–carry– forward forwarding to preserve packet progress across outages, and adaptive source redundancy to improve delivery under variable conditions. It is implemented in ns-3 and compared against fairness-matched baselines under the same topology, traffic, and energy assumptions. The study focuses on fairness-matched evaluation because delivery gains in batteryless networking are often difficult to interpret when protocols are compared under changing conditions or when realized multi-hop behavior is assumed rather than checked through explicit multi-hop metrics. Extensive simulation experiments under multiple load, distance, harvesting, topol- ogy, and hop-depth settings show that WARP-EH improves packet delivery and goodput over the matched baselines while keeping control overhead below the SCF baseline. Topology and sink-relay metrics further indicate that the claimed multi-hop behavior is realized under both source-count and minimum-hop stress settings, and 2the adaptive-redundancy controller is measurably active although the present policy still requires further tuning. Overall, the thesis provides a reproducible, fairness-matched, and metric-backed evaluation of batteryless multi-hop forwarding. Within the modeled scope, WARP-EH achieves higher delivery and goodput than the fair baselines while preserving explicit multi-hop behavior and making its remaining limitations visible.