In our prior work, a Body Sensor Network (BSN) system aimed at increasing safety of bomb disposal operatives during missions has been developed. Although this system served well the application at hand in terms of the on-line data processing capabilities, not all of the design constraints have been catered for. One of the critical requirements of such a safety-critical system is that the messages, including useful data, information and alerts, be reported to the remote station reliably and timely. However, the wireless link, in a bomb disposal environment, suffers from intermittent disruption due to the common use of signal jammers during missions, and frequent temporary obstruction of the radio signal as the user moves about. In order to minimize the safety-critical information reporting loss and delay, in this paper, a priority based message transmission protocol is proposed which features message prioritization, wireless link quality aware message store and priority based message transmission, rule based message filtering, and messages transmission rate automatic adaptation. The protocol has been implemented, and integrated within the BSN prototype. The evaluation of the system was performed with volunteers following mission like regimes in a controlled environment.
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