5.1 What Is 2.5G?

As the question implies, just what is 2.5 Generation (2.5G)? Well, 2.5G, or the next generation transitional technology, is the method or methodology from which existing cellular and Personal Communications Service (PCS) operators are migrating to the next generation wireless technology referenced in the International Mobile Telecommunications-2000 (IMT-2000) specification. 2.5G enables the wireless operators whether they utilize in cellular, PCS, or Universal Mobile Telecommunications System (UMTS) spectrum to deploy digital packet services prior to the availability of 3G platforms. The specific technology and implementation path that each operator must make or has made follows a similar decision path. The decision path that is followed is driven largely based on the existing infrastructure that has been previously deployed, the spectrum that is available and will be available, the growth rate, and of course the expected services being offered.

Obviously, the decision on which platform to utilize involves guesswork and decisions based on a fundamental belief that particular technology platforms will enable services that are yet to be developed. The 2.5G platforms are meant to provide the bridge between the existing 2G systems that have already been deployed and those envisioned for 3G.

Several platforms are leading the 2.5G effort; they are as follows:

• General Packet Radio Service (GPRS)/ High Speed Circuit Switched Data (HSCSD)

• Enhanced Data Rates for Global Evolution (EDGE)

• Code Division Multiple Access (CDMA2000) (phase 1)

The 2.5G platform chosen for the operating system needs to involve...