Software Defined Radio
Wireless Sensor Networks
Short Range Devices (SRD) are increasingly employed in urban sensor networks using different communication protocols. That becomes a key problem in the gateway design, since its cost and energy consumption increase with the number of implemented technologies. This cost and energy can be reduced by using a reconfigurable gateway to perform the biggest part of signal processing digitally, as it is done in Software-Defined Radio (SDR).
As several received signals should be simultaneously digitized, Analog-to-Digital Converter (ADC) must be able to treat the whole frequency band used by SRD. These signals can be received with a big difference of power, thus the ADC must have a high enough resolution to be able to properly demodulate each of them. The ADC requirements must then be described, taking into account the urban sensor networks constraints. To demodulate each signal, a required resolution of 21 bits is obtained from an exemple based on the SmartSantander deployment. As this resolution can't be achieved with the SRD bandwidth constraints, another way must be found to digitize the signals.