Not only are LTE, UMB, and WiMAX based on OFDMA technology, all three will be based on IP-only services with no backwards compatibility for circuit-switched services. To this end, there is a real break"”a discrete change"”in technologies when moving to 4G; therefore, service providers don't necessarily have to select the evolution path of the 2G or 3G standard that they are currently using when they move up to 4G.
For example, it's true that UMTS service providers would most likely move up to LTE. Handsets will be backwards compatible to their existing 3G networks. The LTE radio network should connect seamlessly to their existing core network infrastructure and services. But there may be some providers that are willing to make a break and switch to WiMAX if they think they can gain a competitive advantage.
Some EVDO service providers don't see their evolutionary move"”UMB (EVDO rev. C)"”coming soon enough. To illustrate, a number of providers in
Consequently, backers of all three technologies have reason to push harder on their respective standards bodies, technology providers, and test-solution vendors to have answers ready for service providers in 2009.