Sensors Deployed in RF-Hostile Environments Using Acoustic Communications and GNU Radio

Abstract

Sensor networks are increasingly required in environments where conventional radio-frequency communication is unreliable, attenuated, or unavailable. Examples include dense metallic structures, liquids, enclosed industrial assets, and high-multipath environments where RF propagation is constrained. This paper presents a GNU Radio-based acoustic communication approach for connecting low-data-rate sensors in RF-hostile environments using orthogonal frequency division multiplexing (OFDM) with packet framing based on preamble and postamble detection. The proposed system targets short text and sensor-status messages rather than high-throughput data transfer, reflecting monitoring applications where reliability, repeatability, and environmental tolerance are more important than bandwidth. Implemented in GNU Radio, the acoustic modem can be developed, tested, and modified using SDR principles. OFDM improves robustness in multipath acoustic channels by distributing data across multiple subcarriers and using a cyclic prefix to reduce inter-symbol interference. A preamble supports packet acquisition and synchronisation, while a postamble assists message-boundary detection and validation. Experimental work demonstrates that acoustic signalling can provide an alternative communication path where RF links are limited or unavailable. The paper discusses system architecture, GNU Radio implementation, framing, acoustic channel challenges, and intended sensor-networking applications, contributing a practical SDR-based framework for short-message acoustic sensor communication in difficult physical environments.