Tackling timing offsets when separating co-channel signals

Abstract

In this paper, we propose a method for obtaining a resynchronized symbol rate sampled co-channel signal from a sum of suitably oversampled co-channel signals which have the same data clock but are not necessarily exactly time-aligned. The method works by estimating the relative timing offsets of the data clocks of the different up-link signals and using them to design a bank of filters operating at symbol rate whose outputs can be added to give a resynchronized signal. The filters can be designed to minimize the noise gain as well as force this signal to adhere to a signal model used very often in co-channel signal separation methods.