Linearisation benefits for ultra-wideband amplifiers in SDR RF front-ends for reconfigurable radio environments

Software defined radio (SDR) technology foundation of reconfigurable radio networks will benefit greatly from having ultra-wideband RF high power amplifiers (HPA) which, for reasons of power efficiency and battery lifetime in mobile units, will have to be operated into nonlinear regions with the consequent deterioration in modulation fidelity. By assessing the capacity and benefits of linearisation schemes to offset this nonlinearity impairment initial insights are provided into ways of tackling this problem of quantifying modulation fidelity impairments and thus establishing means to dynamically, and smartly, configure linearisation schemes and HPA operating point matches for the different single and multicarrier modulation types expected in a future reconfigurable mobile radio environment The initial work undertaken in this field and described here is based on assessing various degrees of HPA linearisation in channels carrying pi/4 DQPSK signals with and without adjacent channel interference (ACI).