Controlled Interference Generation for Wireless Coexistence Research

Abstract

In recent years, we have witnessed a proliferation of wireless technologies and devices operating in the unlicensed bands. The resulting escalation of wireless demand has put enormous pressure on available spectrum. This raises a unique set of communication challenges, notably co-existence, Cross Technology Interference (CTI), and fairness amidst high uncertainty and scarcity of interference-free channels. Consequently, there is a strong need for understanding and debugging the performance of existing wireless protocols and systems under various patterns of interference. Therefore, we need to augment testbeds with tools that can enable repeatable generation of realistic interference patterns. This would primarily facilitate wireless coexistence research experimentation. The heterogeneity of the existing wireless devices and protocols operating in the unlicensed bands makes interference hard to model. Meanwhile, researchers working on wireless coexistence generally use interference generated from various radio appliances. The lack of a systematic way of controlling these appliances makes it inconvenient to run experiments, particularly in remote testbeds. In this paper, we present a Controlled Interference Generator (CIG) framework for wireless networks. In the design of CIG, we consider a unified approach that incorporates a careful selection of interferer technologies (implemented in software), to expose networks to realistic interference patterns. We validate the resemblance of interference generated by CIG and interference from represented RF devices, by showing the accuracy in temporal and spectral domains.