Here's an interesting report from PC World about this years state of mobile networks in the US with a bunch of measurements and comparisons of previous years. By and large, improvements are impressive but there are a number of things I haven't quite figured out.
First, the round trip delay times they are quoting. In all networks, even including Verizon's new LTE network, latency values beyond 100 ms are given. When I compare that to HSPA+ networks here in Europe, same technology as that of AT&T and T-Mobile US and the typical latency values of 60 ms, I don't quite know where the extra delay comes from!?
And second, the data speeds. Good to see that all carriers have now left the sub-1 MBit/s average speed range and moved up significantly up the ladder. The 6+ MBit/s measured in downlink direction for Verizon's LTE network (in 10 MHz bandwidth) and around 3.5 MBit/s for T-Mobile US's network (in 5 MHz bandwidth) compare very well to the 4.5 MBit/s measured in German networks in comparable measurement campaigns. But what about maximum achievable speeds in the network?
And by that I don't mean theoretical peaks, those can be taken from the standards documents. What I mean is maximum speeds that can be reached in the live networks under very good signal conditions. In Germany, networks go as far as 12 MBit/s today on one carrier or 24 Mbit/s if you take the second 5 MHz carrier into account that is deployed in bigger cities for additional capacity (sorry, no reference here, as the values are from the print version of a magazine, my personal record is 11 MBit/s). The article seams to dance around those values but quite never mentioning them.
Agreed, average speeds also take overall load in the networks into account, but the article does not say at which times of the day (or night?) the measurements were taken. So one has to be a bit careful here but by and large it's a good indicator, especially for smartphone use. But maximum achievable speeds are just as important, as some people using the network for connecting their notebooks to the Internet benefit from maximum speeds if they are clever enough to look for a good place when using their device at home or in public, i.e. be close to a window, have a look at the number of signal bars, etc.
So again, a good article, but some interesting details are unfortunately missing.
Just a thought on the higher delays in comparison to Europe you mentioned:
Since PC World definitely would have measured End-to-End RTTs, maybe US Wireless Carrier’s infrastructure that’s necessary to enforce fair use policies, metered billing, lawful interception and whatnot is even more bloated than in Europe.
Also, maybe they already have some kind of Deep Packet Inspection in place and on every packet, a lookup in the whitelist tables has to be performed (whitelist currently might only contain “*/*” so every packet gets a ‘do not inspect’).
It’s not only about speed and RTT:
http://www.bgr.com/2011/03/28/htc-thunderbolt-review/