CCDF and Monte Carlo Analysis of a Digital Polar Transmitter for Ultra-Wideband System

Polar modulation has been adopted by modern wireless systems due to its high power efficiency. In this paper, a novel behavioral model for a digital polar transmitter is presented. The polar transmitter contains an array of amplifiers, which are controlled digitally. A system level simulator is used to model each amplifier. The effects of different number of stages on the mandatory data rates are studied with respect to the error vector magnitude, in conformance to the ultra-wideband standard. Next the complementary cumulative distribution function is studied for a four-stage digital polar transmitter in order to gain an understanding of when each individual stage is turned on. Lastly, nonlinearity, modeled as gain variation for the different parallel stages, is included for a four-stage digital polar transmitter when the data rate is 480 Mbps. Results demonstrate the feasibility of obtaining high efficiency using digital polar transmitters for multiband OFDM UWB systems.