4G? What's 4G?Monday, July 14, 2008
This industry really amazes me sometimes-people standing in line for the latest iPhone, people wanting to build out a nationwide network with free Internet access at 2100 MHz and now the rush to fourth-generation technologies.
The push is coming from the equipment vendors and those who believe that data speeds faster than we already have will be the holy grail of bringing the Internet to the wireless world. The fact remains that today's broadband wireless speeds are higher than 1 Mbps, yet the percentage of monthly revenue being driven to the network operators is only in the 20% range and there is still a lot of capacity going unused.
Add to this that the WiMAX folks, who only recently received word that the ITU now considers WiMAX to be an approved 3G technology, are trying to make us all believe that WiMAX is really the first of the 4G technologies and that it will arrive on the scene several years before LTE or UMB, the other two contenders. At the moment, I don't know of any organization, including the ITU, that has come up with a definition of 4G. We know it will be IP-based and it will make use of OFDMA instead of or in conjunction with CDMA, but beyond that we don't know what it is.
Looking at the specifications published by the 3GPP (LTE) and 3GPP (UMB), we can see some of the characteristics that most of today's network equipment manufacturers, network operators and handset vendors have included in the standards. First, both LTE and UMB are designed to be spectrum efficient, capable of operating in a band as small as 1.25 MHz out to 20 MHz. This makes both of them ideally suited for the 700-MHz band where spectrum allocations are 5X5 and 6X6 for the most part.
The high data speeds being bandied about are theoretical in nature and based on a system deployed in a full 20 MHz of spectrum. This is one of the issues with comparing WiMAX and existing 3G networks-unless you compare their capacity, data speeds and other perimeters in the same amount of spectrum, you can get some very skewed numbers in favor of WiMAX. WiMAX systems that are planned and underway at 2.5 MHz have more bandwidth available to them than existing 3G (HSPA and EV-DO) networks, so of course WiMAX numbers appear to be better. But in my book, just because these folks are using more spectrum and claiming to be obtaining higher data rates does not make WiMAX a 4G technology. In fact, the realists in the WiMAX community admit that a single WiMAX carrier will be capable of providing 5 Mbps down to a device and 1 Mbps up. These speeds are good, but they are also available with both HSPA and EV-DO Rev A for the most part, and both are quickly being enhanced to increase both their throughput and capacity.
If you live in or near the Silicon Valley, you might want to attend the WCA's panel on Tuesday afternoon, July 15, entitled, "Next-Generation Mobile Broadband-The 4G Summit." Iain Gillott, founder and president of iGR and a well known and respected analyst will moderate a distinguished panel made up of Jack MacLeod, principal vice president and CTO of Bechtel, Barry Dave, executive director of products and services at Clearwire, Jim Orr, principal network architect, Fujitsu Network Communications, Jon Hambridge, EVP and CMO, NextWave Communications, Samir Khazaka, senior director technical marketing Qualcomm, Gennady Sirota, VP of product management, Starent, and Lee Tjio, director of advanced technology and strategy for Verizon Wireless.
Sounds like a very interesting panel and I am sure Iain will keep it lively and keep things in perspective. Perhaps the most interesting panelist to me will be Jack MacLeod from Bechtel. In addition to building thousands of cell sites, Bechtel now has a test lab where it runs technologies through their paces. I do wonder if Barry Davis from Clearwire will have any real-world speed and capacity data available. Clearwire isn't talking much about performance, could it be that even with all of that bandwidth it is on a par with the rest of the 3G community?
Andrew M. Seybold.