Practical Residual Interference After Cancellation for Constant Envelope Modulation With Data-Aided Synchronization

Abstract

Interference cancellation (IC) is a well-known technique for improving bandwidth utilization in wireless networks. In this paper, we evaluate the practical residual interference of IC with constant envelope modulation in a flat fading environment for a low-power wide area wireless sensor network application, both analytically and experimentally. We propose a new model for the residual interference power, which is the power of the packet being canceled times a random variable. We derive the mean, variance, and distribution of the random variable considering the arbitrary overlapping scenario between two packets with one-time IC. Then, we show how the method can be applied recursively to model the residual interference power when multiple packets are canceled in ordered successive IC. In contrast to the conventional model, we find that this factor varies for different overlapping scenarios and is a function of the signal-to-interference-and-noise ratio of the preamble of the packet being canceled and of the overlapping degree. The theoretical statistics of the residual interference assume maximum likelihood estimation of synchronization offsets.