Cellular communication has experienced tremendous improvement in performance and efficiency over the past few decades. The high-power consumption of conventional low-power wide area network receivers employed in applications such as smart meters, environmental sensors, threat monitors, and other Internet of Things (IoT) applications, often dictates overall device battery life. Even though many such applications communicate at low-average throughputs, the power of the radio can be high due to the need for frequent network synchronization.
Typically, sensitivity, frequency and power consumption are tradeoffs, so the design of wake-up receivers (WuRX) that simultaneously achieve both has been a challenge. Interference resilience is also an important metric for WuRXs since false alarms cause unwanted power dissipation in sensor nodes, while missed detections result in sensor network malfunctions.
To reduce the power consumption, Northeastern University inventors present a novel Ultra Low Power Wake up Radio (WUR) design which detects the incoming RF signal independent of the interference in the channel. The power of the received signal is detected with a novel design of the Receiver Signal Strength Indicator (RSSI). Based on the power of the incoming signal, this RSSI circuit generates a unique code and subsequent processing can be based on the code received. Hence the power of the received signal maps to a code which improves the bit error rate (BER) of the RF receiver. The entire code for the Wake Up Radio can be received with extremely low power consumption (few nWs)
Self-powered ubiquitous IoT devices can leverage WUR capability to enable low power communication, significantly increasing their operational lifetime. Battery replacement or deployment will not be needed which can in turn reduce cost and weight of many IoT devices. Also, interestingly, noise and interference can improve FOM of the Receiver. The presence of ambient noise in the channel aids to improve the sensitivity of the design.