13.1 What Is 4G?

Technology keeps progressing. Perhaps in 10 to 20 years from now, today's 3G mobile systems will be perceived as using old technology, unable to provide the services needed by new and upcoming applications. Such perceptions drove the move from 2G to 3G systems and from 1G to 2G systems before that. There are many different views of what the fourth generation (4G) of mobile systems should look like. There are some characteristics that are common to many of these visions, including the following:

• Order-of-magnitude bandwidth increases. 4G systems probably will have data rates higher than those of 3G systems, by an order of magnitude or more. Since 3G systems in theory can provide data rates up to the order of 2 Mbps, and proposed incremental improvements go up to 10 Mbps, 4G bandwidth may need to provide tens of Mbps or hundreds of Mbps. However, there is a lot of debate about the need for such kind of bandwidth on wireless systems. Proponents of such data rates could point to similar increases in the memory storage required for PCs. Memory requirements always go up, and similarly, communications bandwidth requirements always go up. That new applications will need higher data rates is an evolutionary force that cannot be stopped. The new multimedia applications will demand high data rates. On the other hand, conservative skeptics claim that the costs of providing the additional bandwidth will not justify moving in that direction. Most of the time, when one...