During the evolution from GSM/GPRS to 3GPP R99, brand UTRAN introduced includes such key technologies as WCDMA, power control, multipath Rake receiver.
In addition, four QoS service types are put forward and cell peak rate supports up to 2 Mbps. CN basically develops from GSM/GPRS CN.
It reduces the influence on GSM/GPRS CN caused by the introduction of UTRAN CN furthest. Most representative features of R4 from R99: Separation of CS domain control layer and transmission layer, convergence of transmission resources in CS and PS domains, and increase of resource transmission efficiency.
UTRAN in R4 version does not have substantive evolution and only performs some optimizations.
During the evolution from R4 to R5, IP multimedia subsystem is introduced into CN and the interface connecting GERAN is added.
There is great change in UTRAN: IP transmission technology and HSDPA are introduced, which makes peak rate of the cell up to about 10 Mbps, much greater than the peak bandwidth that R4 and R99 versions can support (in the field, WCDMA supporting HSDPA is called 3.5 G). R5 also supports Iu Flexible, allowing a RNC to access several MSCs or SGSNs simultaneously, which saves investment on access network resources for operators.
intercommunication of WLAN and UMTS. UTRAN evolution includes: MBMS, HSUPA, enhanced HSDPA, wave cluster figuration technology to increase coverage capacity, 3GPP RET and MOCN.
In R7 plans. WCDMA will be developing in total IP direction. In addition, intercommunication of UTMS with other networks (such as, VLAN) and enhanced MBMS will be increased.