Most of us don't put much stock into the claims of mobile carriers that unlimited data users slow down the network for everyone. We tend to think that the carriers are just using excuses to throttle our connections and charge us more money. But according to recent tests from OpenSignal, speeds at AT&T and Verizon are indeed slowing down thanks to unlimited data users.
OpenSignal writes, "Six months after reintroducing unlimited plans, Verizon and AT&T experienced a marked decline in 4G speeds in our tests. The impact appears to have hit Verizon the most. Its average LTE download test fell 2 Mbps to 14.9 Mbps in the six months between reports."
As speeds at AT&T and Verizon have declined, T-Mobile and Sprint have increased their network speeds. Both of these networks have offered unlimited data plans longer than AT&T or Verizon. OpenSignal says that T-Mobile and Sprint have seen no adverse effects on their network speeds from unlimited plans. In fact, OpenSignal found in its testing that T-Mobile had the fastest network speeds of all major carriers with average LTE download speeds of 17.5 Mbps and overall speeds of 16.1 Mbps.
As for what's causing the decline in speeds at some carriers, OpenSignal wrote, "What's causing this fall-off in experienced speeds? The answer is most likely congestion. Cellular networks are shared networks, meaning individual connection speeds are dictated by the total amount of demand for data at a particular cell site. If that demand increases — either through more customers or more data usage from existing customers — then average connection speed for all users starts dropping. We may well see this trend continue as more Verizon and AT&T customers take advantage of these new unlimited plans."
T-Mobile also beat Verizon in another metric, OpenSignal writes, "T-Mobile edged out Verizon in our 4G availability metric, but it was a very close call. Our testers were able to find a 4G signal on T-Mobile 90.9% of the time compared to 89.8% of the time on Verizon."
Tests to determine which network was the fastest in cities found that T-Mobile and Verizon were neck and neck. While T-Mobile was best in the nationwide metrics, the two operators ended up in a tie in some markets. One of the two carriers won or tied in all of the 32 markets OpenSignal examined.
To compile the report, OpenSignal analyzed over 5.07 billion data points collected form 172,919 OpenSignal users between March 31 and June 29. Slower data speeds on two major carriers aside we can thank T-Mobile for the resurgence in unlimited data plans. T-Mobile made unlimited data its only offering last year and other carriers were forced to follow suit. Verizon appears to be trying to control network congestion by throttling speeds on certain services. It admitted in July that it was testing network optimization with the throttling of Netflix and YouTube.