Today you can surf the Web, stream music, and download e-mail attachments on the go at a decent clip. Tomorrow you’ll be able to stream high-quality video anywhere, make VoIP calls without a hiccup, and upload huge files without a second thought. That’s the difference between third-generation mobile data networks—known as 3G—and the fourth-generation (4G), and two technologies have emerged that will vie to become the standard of choice for demanding mobile workers. So how far away is this wireless utopia, what is the difference between these two 4G flavors, and how did we get here?
The four largest U.S. wireless carriers have upgraded their networks to offer 3G data. AT&T and T-Mobile have deployed HSDPA networks (or High-Speed Downlink Packet Access). Sprint and Verizon Wireless use EV-DO Rev. A, which stands for Evolved Data Optimized. Typical download speeds for each range from 600 Kbps to 1.4 Mbps, and upload speeds are between 500 and 800 Kbps. To give you an idea of what these speeds mean, you could download an average-size MP3 file (3.5 MB) in as little as 28 seconds, and upload a 2MB PowerPoint presentation in 25.2 seconds.
But 3G just isn’t fast enough for the warp-speed pace of the average road warrior’s life.
For instance, most people wouldn’t dream of carrying on a video chat over today’s mobile broadband. 4G networks will make this and much more possible by dramatically increasing speeds. Over Mobile WiMAX, for example, you’ll be able to download that same MP3 in 5 seconds and upload that PowerPoint in 6.4 seconds. LTE, the other 4G contender, will perhaps offer even faster data rates, but it’s not nearly as far along in development. Here’s how the two technologies stack up.
Industry Support
Mobile WiMAX: In May, Sprint and Clearwire agreed to combine their existing Mobile WiMAX initiatives to form a new company, which will also be named Clearwire. The new Clearwire will receive $3.2 billion in funding from Bright House Networks, Comcast, Google, Intel, and Time Warner Cable. Mobile WiMAX is also supported by more than 100 infrastructure and device vendors including Alcatel, Beceem, Motorola, Nokia, Samsung, and Texas Instruments.
LTE: LTE is part of the third-generation membership project (or 3GPP), and it’s backed by such major wireless carriers as AT&T, China Mobile, Verizon Wireless, and Vodafone. Handset manufacturers are on board, too. NTT DoCoMo recently demonstrated its first LTE-based handsets. On the infrastructure side, both Ericsson and Nokia-Siemens have expressed their support for LTE.
How the Technologies Work
Mobile WiMAX: This 4G technology operates in the 2.3-GHz, 2.5-GHz, 3.5-GHz, and 5.8-GHz frequency bands. Clearwire has 30 to 50 MHz of available spectrum inside the 2.5-GHz band it needs to launch a mobile broadband network. The available spectrum is important for allowing multiple users online at once to consume large amounts of data. However, Mobile WiMAX doesn’t have quite the range and indoor coverage that LTE will likely offer. This is only because it uses the 2.5 GHz band. Clearwire claims that cell site densities will be increased in urban areas and in regions with more hills and trees than in flatter parts of the country. Experts claim that indoor base stations using wired broadband connections will help alleviate issues of interference on both LTE and Mobile WiMAX networks.
LTE: LTE, like Mobile WiMAX, is a new air interface that will require new hardware and software. It will require the new 700-MHz spectrum, which AT&T and Verizon Wireless recently acquired parts of through the FCC’s spectrum auction. The unique advantage of the low frequency is that it is better suited for passing through office buildings and walls in urban environments. LTE in 700-MHz can also cover longer distances than the Mobile WiMAX in 2.5 GHz, but it is believed that more cell sites will be required to match the capacity of 2.5 GHz.
How Fast Will It Be?
Mobile WiMAX: Clearwire’s CTO, John Saw, told us that he has seen real-world speeds for Mobile WiMAX at 5 to 6 Mbps on the downlink and 2 to 3 Mbps on the uplink. The Xohm network, which is backed by Sprint and has entered into an agreement to merge with Clearwire, has claimed speeds ranging from 2 to 4 Mbps on the downlink and 1 to 2 Mbps on the uplink.
LTE: Verizon Wireless expects its LTE data speeds to be nearly identical to that of Mobile WiMAX: 5 to 6 Mbps downloads and 2 to 3 Mbps uploads. However, AT&T president Ralph de la Vega and 3G Americas’ president Chris Pearson believe that HSPA+ will compete with WiMAX first, with a network that offers 3 to 5 Mbps on the downlink and 1 to 3 Mbps on the uplink. Verizon Wireless claims that AT&T’s LTE solution will use the same technology as its own, and the only speed differences will be the result of deployment techniques.
When Can I Get It?
Mobile WiMAX: Mobile WiMAX is up and running now in select markets. It’s been tested in Baltimore, Chicago, and Washington, D.C., and in May, Sprint and Samsung declared that Mobile WiMAX was ready for commercial use in Baltimore and Washington, D.C. Clearwire is testing in Seattle and Portland, and it expects to cover 23 million points of presence (POPs) by the end of the year in Atlanta; Grand Rapids, Mich.; Las Vegas; and Portland, Ore.
The new Clearwire expects 60 to 80 million new POPs by the end of 2009. The Clearwire/Xohm transaction is expected to be complete by the fourth quarter of this year, after it receives regulatory approval. However, Xohm users will become integrated with Clearwire as soon as the markets open. By 2010, Clearwire is targeting a network that will cover between 120 and 140 million people in the U.S. Although devices will likely be only Mobile WiMAX–enabled at first, it’s expected that handset and consumer electronics manufacturers will offer dual-band support, offering the ability to fall back to EV-DO (or HSPA) in areas where Mobile WiMAX isn’t available.
LTE: Verizon Wireless and Vodafone currently have an ongoing trial. Verizon expects its network to be ready in 2009, but the commercial launch will be paced by device availability and the demand for applications that LTE will enable. For that reason, Verizon Wireless claims it may not hold a commercial launch until 2010 or later. AT&T doesn’t have any ongoing trials, but it will offer HSPA networks in 350 markets by the end of the year, and the carrier plans to roll out LTE by 2010 or 2011.
