Ultra-wide-band transmitter for low-power wireless body area networks: design and evaluation

The successful realization of a wireless body area network (WBAN) requires innovative solutions to meet the energy consumption budget of the autonomous sensor nodes. The radio interface is a major challenge, since its power consumption must be reduced below 100 μW (energy scavenging limit). The emerging ultra-wide-band (UWB) technology shows strong advantages in reaching this target. First, most of the complexity of an UWB system is in the receiver, which is a perfect scenario in the WBAN context. Second, the very little hardware complexity of a UWB transmitter offers the potential for low-cost and highly integrated solutions. Finally, in a pulse-based UWB scheme, the transmitter can be duty-cycled at the pulse rate, thereby reducing the baseline power consumption. We present a low-power UWB transmitter that can be fully integrated in standard CMOS technology. Measured performances of a fully integrated pulse generator are provided, showing the potential of UWB for low power and low cost implementations. Finally, using a WBAN channel model, we present a comparison between our UWB solution and state-of-the-art low-power narrow-band implementations. This paper shows that UWB performs better in the short range due to a reduced baseline power consumption.