High efficiency digital polar transmitter for cellular handsets

In this paper, the architecture of a digital polar transmitter system for cellular multi-mode handset is presented with hardware implementation emphasis on 2/2.5G systems (GSM/EDGE). The most prominent feature of this architecture is it's ability to employ a highly nonlinear PA, this highly efficient. This is accomplished via our novel real-time nonlinear closed-loop predictive calibration for correcting the PA's nonlinearity. In addition, our architecture makes it possible to eliminate or minimize the need for extensive factory calibration since our predictive realtime auto-calibration scheme does not require much prior knowledge of the system characteristics.