Performance of nonlinear receivers in mobile communications

Nonlinear receivers have been used in mobile communication systems to simplify receiver structure. Digital receivers with bandpass hard-limiter nonlinearity in the frontend are considered in this work. Nonlinear operation on the received signal degrades the performance of some of the baseband processings such as equalization and diversity combining while improves some others such as synchronization. In this paper we discuss the effect of nonlinearity on receiver design. In particular, synchronization, diversity and optimum combining schemes are discussed. It is shown that the synchronization technique can be designed to benefit from hard-limiting, and with a two branch antenna diversity combining scheme based on the received signal strength measurements there is little or no loss of performance. In the absence of RSSI measurements, the fading channel response may be estimated from the phase error