Moving from GSM to 3G

The figure is from: dictionary.zdnet.com/definition/WCDMA.html

The evolution from GSM to 3G begins with an upgrade of the GSM network with packet-data capabilities by adding GPRS. This introduces end users to the “always connected” experience.

The next step is the introduction of 3G services, during which the GSM standard is developed in two ways: (1) WCDMA as the 3G radio access for the wideband spectrum and (2) EDGE as the 3G radio access for the existing GSM spectrum WCDMA is a new, highly efficient technology for both packet and circuit-switched traffic. It provides more capacity and higher data rates to enhance the user’s experience of existing voice and data services as well as new advanced mobile services beyond voice.

EDGE is a standardized set of improvements to the GSM radio interface that brings higher data rates and increased spectral efficiency for data services. With EDGE, the operator can have three times more subscribers than with GPRS or triple the data rate. EDGE provides in principle the same type of 3G services as WCDMA, but with lower data transfer rates. Implementing EDGE is fast and cost-efficient. EDGE uses the same channel structure, frequency planning, protocols and coverage as today’s GSM. Operators will be able to achieve more with the same physical resources.

Because the GSM frequency bands are a substantial part of an operator’s total spectrum assets, it will become increasingly important to be able to use the GSM spectrum for 3G services. The choice will not be between WCDMA and EDGE, but how to best utilize both WCDMA and EDGE.

In a word, there will be no revolution to 3G, but rather an evolution and, because of the practical need to re-use the existing infrastructure and to take advantage of new frequency bands as they become available, that evolution will look a bit different depending on where you are.