Network testing showed both performance and availability of advanced LTE features like carrier aggregation
If you’re hitting the road this holiday weekend, cellular coverage on the nation’s highways is a good thing to know before you go, with Thanksgiving weekend road travel predicted to be at the highest volume in more than a decade and an estimated 51 million Americans traveling 50 miles or more from home according to AAA. But most cell network testing focuses on metro area markets, not on the highways that run between them, according to Paul Carter, CEO of network benchmarking company Global Wireless Solution.
So GWS spent time this summer drive-testing the coverage of the four national carriers on American’s highways in 49 states (the 48 contiguous states plus Alaska), with a total of 52,000 miles driven while active testing was underway.
The data resulting from conducting nearly 703,000 controlled voice and data tasks on the same devices across the country’s highways paints a different picture than other testing methods, Carter noted. Crowd-sourced data, he said, relies on information from a wide variety of devices with different operating system versions and capabilities — so it reflects the capabilities of a given carrier’s device base more than the networks themselves and can put carriers with an older device base at a disadvantage. GWS used Rohde & Schwarz’ Diversity Benchmarker II test equipment with Samsung Galaxy S7 devices and its own Mobistat platform for data evaluation and reporting, with testing conducted between March and July of this year.
Among GWS’ findings:
-There were big variations in data speeds. AT&T had the fastest download speeds for tests that mimicked watching video clips on a site like YouTube and was about 33% faster than second-place finisher Verizon.
-AT&T and Verizon tied for upload speeds in tasks like posting to social media and also for data connection reliability, with more than 99% of tasks able to be completed successfully.
-T-Mobile US had the worst reliability rating, with a call success rate of 89% (compared to top performer Verizon at 97% and 96% call completion for AT&T). Those numbers were for their LTE networks; on 2G/3G circuit-switched calls, T-Mobile US had a 90% call completion rate while all the other carriers had better rates, with AT&T and Verizon coming in at 97%.
-Sprint had the worst overall numbers for task completion, with only 85% of tasks able to be completed. Download speeds on Sprint’s network “were closer to that of AT&T’s 3G network than they were to any of its’ competitors LTE network capabilities,” GWS said.
Above and beyond performance statistics, though, GWS was able to assess what LTE network features were in play and how often – something that crowd-sourced data can’t provide, Carter noted. GWS found that carrier aggregation was available on AT&T’s network about 30% of the time during testing, with a similar figure for Verizon, Carter said. The other two national carriers had carrier aggregation available about 16% of the time, he told RCR Wireless News. The 256 QAM modulation scheme, meanwhile, had very limited availability and was available less than 3% of the time on AT&T’s network and less than 1% of the time on the others, Carter said.
GWS also found that AT&T was able to devote the most resource blocks, as a percentage, to its active users. GWS measured physical resource block utilization rate, or PRB, which “measures the amount of resources allocated to an active user for data tasks in relation to the total amount of network resources available,” according to GWS. Carter said that Verizon – which has been rumored to be impacted by its introduction of unlimited data plans – had the lowest PRB rate among the four carriers, which is an indicator of higher network loading. Still, he pointed out, Verizon had LTE available 97% of the time, including carrier aggregation availability about 30% of the time, and either beat or tied AT&T in speed and successful task completion – so even if it’s network is more heavily loaded, Carter said, performance is still good.
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