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

TL;DR

This study documents the first comprehensive real-world measurements of a dense outdoor SP Wi‑Fi 6E deployment coexisting with indoor LPI Wi‑Fi 6E in a stadium setting. Using 902 SP outdoor APs and ~400 indoor LPI APs at Notre Dame, along with SigCap-enabled smartphones and a spectrum analyzer, the authors quantify usage patterns, cross‑environment interference, and aggregate interference under game-day and post-game-day conditions. Key findings show rapid 6 GHz adoption among clients (about 14%), significant indoor-outdoor coexistence effects especially near windows, and a notable ~10 dB increase in aggregate interference during peak outdoor usage that AFC calculations do not account for. The results inform spectrum policy and highlight practical considerations for hybrid sharing in the upper 6 GHz and related bands, with implications for deployment strategies, channel planning, and potential regulatory updates to account for aggregate interference in dense environments.

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.

Figures (17)

• Figure 1: Spectrum Bands in 6 GHz.
• Figure 2: Measurement locations.
• Figure 3: Wi-Fi 6E deployment at Notre Dame stadium bowl.
• Figure 4: Fixed links.
• Figure 5: AFC plot from Cambium. Yellow bars are the receive frequencies of the three fixed links in the vicinity.