International Journal of Computer Theory and Engineering

Abstract

In post-disaster environments, telecommunication infrastructure is often disrupted due to damage in power and communication lines, resulting in reduced wireless connectivity. This study investigates an External Rescue Publisher (ERP) system to mitigate communication disconnectivity in a simulated post-earthquake indoor environment. A ray-tracing-based simulation using a computer-aided design model was conducted in a typical office setting comprising 30 room scenarios (15 corner, 15 non-corner) across three Philippine Institute of Volcanology and Seismology (PHIVOLCS) Earthquake Intensity Levels (6, 7, and 8) and three subscriber-to-publisher cardinalities (1:1, 1:3, 1:5), yielding 90 simulation runs. Under the baseline in-room ceiling publisher, evaluated across 150 unique subscriber positions at 1:5 cardinality, only 114 nodes (76.0%) satisfied the −91 dBm receiver sensitivity threshold. In contrast, 36 nodes (24.0%) fell below it, with failed nodes exhibiting a median received power of −100.6 dBm against an all-node mean of −80.8 dBm. Failure rates increased with debris severity, from 18% at Intensity Level 6 to 34% at Level 8, and were marginally higher in corner rooms (25%) than in non-corner rooms (23%). Repositioning the ERP outside the room restored connectivity in 57% of affected rooms at nominal transmit power alone, with the remainder requiring incremental power increases of 10–30 dBm. Overall, ERP intervention restored all 36 previously disconnected nodes to at least −91 dBm, a 100% recovery rate, with a median power gain of 21.4 dBm. Power Delay Profile and Power Angular Profile analysis further showed that below-threshold subscribers consistently exhibited smaller delay and angular spreads, indicating fewer resolvable multipath components.