The speed crown today, however, goes to New Zealand, which first launched LTE just two years ago (for more details on how we calculate our country averages see the methodology section). Though LTE-Advanced hasn’t yet taken hold in New Zealand, Spark and Vodafone have launched LTE on two frequency bands each, delivering an awful lot of 4G capacity. As for individual performance goes (based on the operators where we had a large enough data sample), Singapore’s StarHub clocked the fastest average speeds of any global operator at 38 Mbps.
OpenSignal notes that while part of the reason the U.S. is slipping is due to its huge base of subscribers, it hasn't matched the capacity that countries like South Korea and Singapore have put into their networks. The United States has also been slowing in moving to LTE-Advanced.
Within the U.S., T-Mobile was found to deliver the fastest speeds with average of about 12 Mbps, followed by Verizon at 12 Mbps, C Spire and AT&T at 8Mbps, and then U.S. Cellular and Sprint at 6 Mpbs.
Check out the chart below for more details...
Read More [via MacWorld]