Impact of nonlinear amplifiers on the UMTS system

Abstract

We report on the impact of distortions caused by a nonlinear amplifier on the performance of a transmitter for the Universal Mobile Telecommunications System (UMTS). A system overview of the UMTS Terrestrial Radio Access (UTRA) physical layer is given. System simulations of an UMTS transmitter designed for commercial use are described. The degradation of the UMTS transmit signal in terms of error vector magnitude (EVM) and adjacent channel power ratio (ACPR) is discussed and related to the power amplifier (PA) characteristics like 3/sup rd/ order intercept point and 1 dB compression point. Furthermore the impact on the uncoded bit error rate is investigated.