PDF of this tutorial
There are multiple "paths" to 3G as shown in Figure 2. In addition, TD-SCDMA is a 3G technology being considered mainly within the Chinese market.
igure 2. Paths to 3G.
This white paper will focus on the UMTS path to 3G. UMTS is synonymous with W-CDMA and 3GSM.
The standards body for UMTS is the 3G Partnership Project (3GPP). There are currently four releases of UMTS defined by 3GPP.
Release 99
These specifications relate to the addition of the UMTS Radio Access Network (UTRAN), which is typically added to circuit-switched voice infrastructure and GPRS "Internet access".
Release 00 was abandoned in favor of Release 4 and Release 5, hence the inconsistency in the release numbering.
Release 4
These specifications relate to the migration of the circuit-switched voice network to an ATM or IP core network.
Release 5
These specifications relate to the addition of IP Multimedia Services (IMS), which effectively enable person-to-person multimedia sessions.
Release 6
These specifications imply no change to the overall network architecture. Release 6 will add more IMS capabilities, speech recognition, Wi-Fi/UMTS inter-working, radio optimization, etc.
Subsequent sections will provide more detail on Release 99 and Release 4 as these will be the releases utilized for the next few years by the majority of WSPs.
