We conduct to our knowledge a first measurement study of commercial mmWave 5G performance on smartphones by closely examining 5G networks in two U.S. cities. We conduct extensive field tests on 5G performance under diverse conditions including different obstruction levels, phone-tower distances, and device orientations . We systematically analyze the handoff mechanisms in 5G and their impact on network performance. We also study app performance (web browsing and HTTP download) over 5G , and how Internet server selection affects the end-to-end performance for 5G users. Our experiments consume 10 TB of 5G data, conducted when 5G just made its debut in April 2019. These experiments provide a baseline for studying how 5G performance evolves, and identify key research directions on improving 5G users' experience in a cross-layer manner. 
We conduct to our knowledge a first measurement study of commercial 5G performance on smartphones by closely examining 5G networks of three carriers (two mmWave carriers, one mid-band carrier) in three U.S. cities. We conduct extensive field tests on 5G performance in diverse urban environments . We systematically analyze the handoff mechanisms in 5G and their impact on network performance. We explore the feasibility of using location and possibly other environmental information to predict the network performance. We also study the app performance (web browsing and HTTP download) over 5G . Our study consumes more than 15 TB of cellular data. Conducted when 5G just made its debut , it provides a "baseline" for studying how 5G performance evolves, and identifies key research directions on improving 5G users' experience in a cross-layer manner. We have released the data collected from our study (referred to as 5Gophers) at URL
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mmWave
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in two
of three carriers (two mmWave carriers, one mid-band carrier) in three
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under diverse conditions including different obstruction levels, phone-tower distances, and device orientations
in diverse urban environments
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also study
explore the feasibility of using location and possibly other environmental information to predict the network performance. We also study the
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, and how Internet server selection affects the end-to-end performance for 5G users. Our experiments consume 10 TB of 5G data, conducted
. Our study consumes more than 15 TB of cellular data. Conducted
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in April 2019. These experiments provide a baseline
, it provides a "baseline"
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identify
identifies
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We have released the data collected from our study (referred to as 5Gophers) at URL