Practical Residual Error of Interference Cancellation for Spread MSK with a Pseudo-Noise Preamble

Abstract

Interference cancellation (IC) has been proposed to improve bandwidth utilization for the majority of modern wireless networks. We claim that the conventional model for IC residual error, which is that the residual error power is simply a fraction of the power of the packet being cancelled, is overly simplified. In this paper, we evaluate the practical residual error of IC with spread MSK modulation in a flat fading environment for a low power wide area (LPWA) wireless sensor network application. In particular, we address the two-packets-overlapping scenario as a function of the signal to noise ratio (SNR) of each packet and the overlapping degree. Using software-defined radios, we demonstrate that the average realistic residual error power based on packet transmission with a single pseudo-noise preamble is not a constant fraction of the power of the packet being canceled. Rather, it depends on the synchronization and channel estimation errors, which in turn, depend on the SINR of the stronger packet preamble.