In the quest to implement a network of low-power, reconfigurable sensor nodes, it is necessary to aggressively scale the amount of energy each block requires while maintaining full functionality, network connectivity, and data throughput. The RF transceiver block is crucial, as the power dissipation of this block could easily eclipse the entire sensor node power budget if not properly designed. This research focuses on the implementation of an energy efficient RF transceiver for PicoRadio.
There are three key requirements of the RF transceiver. To facilitate low-power communication of bursty sensor node data, the chosen performance metric of the transceiver is the energy required to transmit each bit of data (energy/bit). Second, in order to achieve a low-cost and small form-factor sensor node, high integration of the RF transceiver is important. Finally, because indoor sensor-node environments typically present narrowband fading (varying degrees of attenuation of narrow frequency bands), some mechanism of fading immunity is required.
To meet these requirements, a break from the traditional low-power, narrowband radio design paradigm is necessary. Some key enablers are recent developments in microelectromechanical (MEMs) technology. By utilizing MEMs resonators, it is possible to perform passive frequency translation and filtering. Traditionally, these operations are accomplished with active circuitry (i.e., mixers), consuming large amounts of power in the process. Secondly, the ultimate goal of this MEMs technology is the full integration with active circuitry. Additionally, they allow detection of widely spaced frequency bands, facilitating the design of a fading resistant architecture.
The ultimate goal of this research is a fully integrated, ultra low-power RF transceiver suitable for wireless sensor node applications.