Trading Digital Accuracy for Power in an RSSI Computation of a Sensor Network Transceiver

To handle the rigid power and energy constraints in the Digital BaseBand (DBB) of Wireless Sensor Networks (WSN)s, we introduce approximate computing as a new power reduction method. The Received Signal Strength Indicator (RSSI) computation is a key element in DBB processing. We evaluate the trade-off in RSSI computation between Quality-of-Service (QoS) and power consumption through circuit-level approximation. RSSI elements are approximated in such a way that error propagation is minimized. In an industrial 40-nm CMOS technology, substantial energy savings up to 24% are achieved for every successfully transferred bit in DBB processing in a low- power listening WSN scenario.