Front end power dissipation minimization and optimal transmission rate for wireless receivers

Most wireless battery-operated devices spend more energy receiving than transmitting. Hence, minimizing the power dissipation in the receiver front end, which, in many cases, is the prominent power consuming part of the receiver, is an important challenge. This paper addresses this challenge by solving two closely related optimization problems. Firstly, we optimize the overall power dissipation in an RF front end consisting of a chain of building blocks to satisfy required overall specifications in gain, linearity and noise figure. We extend this into a second optimization problem, namely to maximize the transmission rate that the receiver can accommodate for a given available receiver battery power budget. In fact, the ratio of this transmission rate vs the available receiver power budget serves as the figure-of-merit that allows a formal optimization where, in particular, the (adjacent channel) interference is a critical factor. Our results include closed-form analytical solutions for certain cases. For high signal power, where the noise is limited by interference, the largest bit/s/Hz per nJ drawn from receiver is reached for a transmission rate of 2.3 bits/s/Hz, irrespective of interference power. Numerical results using practical circuit blocks with 90 nm and 65 nm technologies are in close agreement with the analytical results