Analysing Wi-Fi/LTE coexistence to demonstrate the value of risk-informed interference assessment

Effective interference evaluation methods are crucial when making regulatory decisions about whether new wireless technologies should be allowed to operate. Such decisions are highly relevant for both DSA technologies in licensed bands and for technologies coexisting in unlicensed bands. In this paper we demonstrate the benefit of risk-informed interference assessment as an effective method that aids spectrum regulators in making decisions, and readily conveys engineering insight. We apply risk assessment to a Wi-Fi/LTE coexistence study in the 5 GHz unlicensed band. Our contributions are: (i) we apply, for the first time, risk assessment to a real-life problem of inter-technology spectrum sharing; and (ii) we demonstrate that risk assessment comprehensively quantifies the effect of interference in an intuitive manner. We perform extensive Monte Carlo simulations and we consider throughput degradation and fairness metrics to assess the risk of co- and adjacent channel interference for different network densities, numbers of available channels, and deployment scenarios. Our risk assessment results show that no regulatory intervention is needed to ensure harmonious technical coexistence between Wi-Fi/LTE in the unlicensed band. As an engineering insight, Wi-Fi coexists better with itself in locally dense deployments, but better with LTE in sparse deployments. For the large number of available channels typically expected in practice in the 5 GHz band, the risk of interference for Wi-Fi coexisting with LTE is negligible, rendering policy and engineering concerns largely moot.