Energy-efficient networked sensor transceivers

The networked communications requirements for programs such as Future Combat Systems and others have spawned numerous developments in the area of low profile, low cost, yet high performance transceivers. A primary objective for these next-generation unattended devices is maximum mission life, hence the radios employ not only low power circuit designs, but also power-efficient routing protocols and fast acquisition waveforms to support duty cycling. The network architecture of the systems employing these transceivers is similarly optimized. In numerous scenarios, low power (< 1 watt transmitted output) transceivers compose the local network that interconnects relatively closely spaced nodes, typically front line sensors. A typically higher-powered, and higher data rate transceiver within the network provides the longer link (tens of kilometers) to a Command and Control Station. Operational considerations specific to each system, such as the number of nodes, anticipated traffic volume, latency requirements, forward error correction, encryption, etc., are used to determine the data rate for both the local and long haul links. Additional requirements for low probability of detection, low probability of intercept, and anti-jam protection provide the final input to the process of waveform selection or design. In many cases, unique transceivers are designed to satisfy the requirements for each of the two links. However, judicious trade-offs between the two can yield a single dual-mode device capable of operating in a low power, low rate mode for sensor interoperability while also offering higher layer communications. This paper outlines the design considerations for networked sensor system transceivers and presents performance data for prototype systems.