The Emperor has No Problem: Is Wi-Fi Spectrum Really Congested?

Abstract

“Wi-Fi congestion is a very real and growing problem.” So said then-Chairman of the FCC Genachowski in a recent proceeding, and this sentiment is widely heard. However, we are aware of very few engineering studies that have a bearing on this matter, and their conclusions are equivocal. Beyond this, evidence for “congestion problems” in the 2.4 GHz ISM band is anecdotal at best.

While some users no doubt sometimes have service difficulties they ascribe to congestion, that is not sufficient to prove that there is a policy problem. In order to provide a basis for policy decisions, we offer an analysis of congestion metrics and results in the engineering literature. We conclude that there is little consensus on how to measure congestion, and that network metrics are difficult to correlate with user experience.

We therefore propose a list of user experience-oriented service impairment criteria that, if met, would demonstrate that congestion exists to a degree that justifies regulatory intervention: For more than one key scenarios that are provided by an operator or technology there is a significant increase in the percentage of users who can’t complete a valuable task on a persistent, ubiquitous basis in spite of the use of state-of-the-art engineering/deployment best practices, and users’ willingness to pay the market rate for the best available service level.

Based on our assessment of public reports and experimental data, we conclude that there is currently no evidence for pervasive Wi-Fi congestion. We do not claim that the absence of evidence of congestion amounts to evidence for the absence of congestion. However, we do question the argument that congestion occurring somewhere, sometimes is a justification for regulatory intervention.

Keywords: Wi-Fi, spectrum, congestion, regulation, TPRC