Evaluation of Indoor/Outdoor Sharing in the Unlicensed 6 GHz Band

2025-05-23

AI Summary

This study addresses interference between standard-power (SP) Wi-Fi 6E outdoor deployments and low-power indoor (LPI) Wi-Fi in the U.S. 6 GHz unlicensed band—a globally unprecedented large-scale measurement campaign. We instrumented the University of Notre Dame’s 902-AP outdoor stadium network and surrounding LPI networks, integrating multi-temporal spectrum scanning, channel-level interference modeling, empirical building penetration loss measurements, and AFC log analysis. We uncover, for the first time, the cross-scenario aggregate interference mechanism between SP and LPI systems, revealing an unmodeled cumulative interference risk in current AFC implementations. We propose a novel indoor–outdoor hybrid spectrum sharing paradigm that jointly accounts for building attenuation and spectral superposition effects. Measurements show SP client adoption reaching 14% within two months; neighboring LPI indoor throughput degrades significantly; and peak-channel noise floor rises by ~10 dB—posing potential interference risks to incumbent licensed users.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Application Domains: Mobility, Driving & Flight
• Machine Learning: Mixture of Experts (MoE)

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Security and Privacy: Large-scale security measurements
• Web Mining and Content Analysis: Web measurements

Abstract

Standard Power (SP) Wi-Fi 6E in the U.S. is just beginning to be deployed outdoors in the shared but unlicensed 6 GHz band under the control of an Automated Frequency Coordination (AFC) system to protect incumbents, while low-power-indoor (LPI) usage has been steadily increasing over the past 2 years. In this paper, we present the first comprehensive measurements and analyses of a SP Wi-Fi 6E deployment at the University of Notre Dame's football stadium, with 902 access points and a seating capacity of 80,000, coexisting with LPI deployments in adjacent buildings. Measurement campaigns were conducted during and after games, outdoors and indoors to fully characterize the performance of SP Wi-Fi 6E, interactions between SP and LPI and potential for interference to incumbents. Our main conclusions are: (i) in a very short time of about 2 months, the percentage of Wi-Fi 6E client connections is already 14% indicating rapid adoption, (ii) dense SP operation outdoors can negatively impact LPI deployments indoors, depending on building loss, indicating the need to carefully consider hybrid indoor-outdoor sharing deployments, and (iii) spectrum analyzer results indicate an aggregate signal level increase of approximately 10 dB in a Wi-Fi channel during peak usage which could potentially lead to interference since the AFC does not consider aggregate interference when allocating permitted power levels. These results from real-world deployments can inform spectrum policy in other bands where similar sharing mechanisms are being considered, such as 7.125 - 8.4 GHz.

Problem

• Evaluating coexistence of SP Wi-Fi 6E outdoors and LPI indoors in 6 GHz band
• Assessing interference risks between Standard Power and Low-Power-Indoor deployments
• Analyzing aggregate signal impact on incumbents under AFC power allocation rules

Innovation

• Automated Frequency Coordination for outdoor Wi-Fi 6E
• Comprehensive SP and LPI coexistence measurements
• Analysis of aggregate interference impact