Environment and Process Adaptive Low Power Wireless Baseband Signal Processing Using Dual Real-Time Feedback

Abstract

As technology scales below the 45 nm CMOS technology node, RF front ends and baseband processors will need to be aggressively overdesigned to work reliably under worst case channel (environment) conditions as well as worst case manufacturing variations. In this paper, a new dual feedback based design approach is proposed that allows the baseband unit of a wireless OFDM system to adapt dynamically to channel conditions as well as manufacturing process variations. Two nested feedback control loops are used. The first allows the baseband SNR to increase when channel conditions are good and vice versa by modulating system wordlength. The second modulates the system supply voltage in response to the resulting changing wordlength values. Both feedback loops are designed to allow the processor to operate at the minimum power consumption possible without exceeding a specified overall bit error rate across process variability conditions and dynamically changing noise conditions.