Future integrated sensor radios for long-haul communication

As CMOS single-chip radios enter the era of big data, techniques to acquire, communicate, and store sensor data will evolve to address new demands placed by a rapidly changing application space. Research and development on wireless sensor radio communication over the past decade has been largely focused on energy efficiency for short-range communication. However, going forward, sensor radios will require new modes of communication, which include leveraging existing network infrastructure and increasing the communication range of a single device. This article overviews several existing approaches for wirelessly communicating sensor data, followed by potential future strategies to enhance range and connectivity using single-chip wireless sensor transceivers. As an example of devices for longrange sensor communication, a regulator-less CMOS power amplifier specifically tailored for the demands of longer-range sensor data communication is described. This PA was designed to provide a fixed high-output power using a dynamic voltage supply as commonly found in sensor applications where an energy storage element (super capacitor) supplies the transceiver. The PA system is integrated in a 90 nm CMOS process, has a peak output power of 24 dBm, with an efficiency of 12 percent at 1.8 GHz, making this device suitable for data communication over distances of several hundred meters. As the PA supply varies from 2.5 to 1.5 V, the power control loop maintains a constant output power with an accuracy of ±0.8 dB.