Wired Explains: What U.S. Carriers Mean by ‘4G’
In 2011, wireless carriers are banking on you going 4G with your next smartphone purchase.
Verizon says it will release 10 different 4G enabled handsets in the next year. AT&T says it will double that number, with 15 of its own offerings being Android OS-based devices. And T-Mobile, which offers a handful of 4G phones, claims its network is “America’s largest 4G network.”
But with all the wireless industry jargon being thrown around in marketing campaigns these days, it’s still unclear just what each carrier actually means when it touts its network as “4G.”
4G Technologies
Loosely defined, 4G stands for the the fourth generation of cellular wireless standards. In the narrow terms originally defined by International Telecommunication Union standards, it doesn’t count as 4G unless it offers download speeds of 100Mbps to 1Gbps. That’s about 100 times faster than any speeds we’re seeing on networks now.
If we were to judge the networks available to us now by this standard, none of them would be considered 4G.
Luckily for the carriers, we aren’t judging that way — at least, not any more. In December at the ITU World Radiocommunication Seminar in Geneva, the ITU allowed the term “4G” to “also be applied to the forerunners of these technologies, LTE and WiMax, and to other evolved 3G technologies providing a substantial level of improvement” compared to current 3G networks.
AT&T wasted no time embracing the new nomenclature, relabeling its network overnight.
And well it might, as rival T-Mobile has been using the same nomenclature for the same technology since early 2010.
Before we delve into each carrier’s offerings, let’s take a look at the competing technologies being used today.
WiMAX
Developed by the IEEE, WiMAX is one of two competing technologies to blaze the 4G trail. WiMAX, also known as 802.16, is in the same family of standards as Wi-Fi. Sprint and Clearwire own the biggest share of the 2.5GHz spectrum — “the most readily usable licensed spectrum in the United States,” according to information site WiMAX.com – across which WiMAX is carried.
Users can typically expect download speeds of 2-4Mbps, with upload speeds topping out around .4-.5Mbps.
LTE
LTE stands for long-term evolution, the leading competitor to WiMAX for next-generation wireless data. Instead of expending efforts deploying a new network infrastructure — like Sprint has done and continues to do with WiMAX — LTE proponents like AT&T update existing 3G networks. While the WiMAX network is more fully developed at the moment, LTE won’t be widely available until 2013, according to forecasts from both AT&T and Verizon.
But LTE has the advantage in speed. Users can typically expect download speeds of 5-12Mbps, with upload speeds ranging from 2-5Mbps.
HSPA+
This is where it gets a bit tricky. Evolved high-speed packet access, or HSPA+, has been widely considered 3.5G, until the ITU decision in December opened up those terms to a more liberal interpretation. Sprint, Verizon and AT&T weren’t happy. The technology is an incremental approach to upgrading existing HSPA networks,
Speed tests of smartphones on HSPA+ networks have varied greatly, but users can generally expect download speeds of 1-3Mbps, with upload speeds from 0.4-0.8Mbps.
Fuente: Gadget Lab
