A channel monitor for emergency wireless networks

This work describes the design and development of a radio spectrum analysis tool for monitoring the spectrum occupied by a wireless system operating in the unlicensed 2.4 GHz ISM frequency band. Based on the open GNU radio library, the tool makes use of a USRP (Universal Software Radio Peripheral) generic hardware. The design is scalable to other frequency bands for compatibility with other IEEE wireless standards such as the 802.11a. Whereas existing network monitors are based on the idea of measuring the RSSI level, the packet error rate or the Interference Temperature to establish radio occupancy, our approach considers the spectrum level (at the physical layer) in discrete frequencies as its main measurement parameter. Therefore, our analyzer can also monitor other technologies working in the same frequency band. This module was tested within our Laboratory´s ad hoc network and the results have demonstrated its ability to discover and suggest the best channel for communication in real time. The current developments is part of our wider research effort into the design of solutions for communication support among emergency rescue teams.