4G: Here It Comes, Ready or Not -- Part I
We said the 4G era had unofficially begun. There is contention over the meaning of the term. Some take a narrow view, some a broader interpretation. The latter group would say that Xohm, while it may be intriguing in a number of ways and certainly "next-gen," is in fact not a 4G service. According to Phillip Redman, a research vice president at Gartner, Xohm is not 4G because the underlying WiMAX technology it uses, 802.16e, fails to meet minimum objectives for 4G set out by the International Telecommunications Union(ITU), a United Nations agency. "They're the ones that decide what is 3G, what is 4G - what is 10G," Redman says of the ITU. "There is a misconception out there right now that 4G is WiMAX, and that is absolutely not true. There is in fact no definition of 4G yet, but there are goals [the ITU] is working towards." What are those goals? 4G networks will be based on Internet protocol (IP), the standard used for sending data over the Internet and other packet-switching networks.
This means that unlike today's 3G networks, which are circuit-switched with an overlay of data carrying capabilities, 4G networks will be entirely packet switched. Mobile voice will be carried as a stream of IP packets - VoIP in other words.4G networks will deliver data throughput to mobile users as high as 100 megabits per second (Mbps), with, it's hoped, an evolutionary path to gigabit speeds. They will feature a higher level of security than existing wireless technologies provide and better implementation of quality of service (QoS) techniques for ensuring smooth flow of time-sensitive data, such as video and voice. And they will use two key underlying technologies: Orthogonal Frequency-Division Multiple Access (OFDMA), a highly efficient digital radio modulation scheme, and MIMO (multiple input multiple output), a multi-antenna system that minimizes data errors and optimizes speed. Speed Matters
Both these last technologies, it's worth noting, are already used in WiMAX 16e, and in Wi-Fi 11n for that matter. Current networks based on 802.16e, including Xohm's, are also already pure IP networks. "The current WiMAX has good characteristics," Redman concedes. "But realistically, [WiMAX] carriers are saying they're going to support 2 to 4 Mbps [data speeds]. We expect 4G to be ten times that. So today, the actual capabilities of the WiMAX network aren't anywhere close to what we expect from 4G."
TAGS:wireless, carriers, Wimax, 4g, Long Term Evolution