Controlling Radio Network Controller (CRNC)
A role an RNC can take with respect to a specific set of Node B’s. This represents the RNC functions that deal with control of subtending Node Bs. There is only one Controlling RNC for any Node B. The Controlling RNC has the overall control of the logical resources of its node B’s.
Drift Radio Network Controller (DRNC)
This represents RNC functions that deal with control of functions during soft handover when the RNC is downstream from the serving RNC and has control over at least 1 Node B who has soft handover leg(s).
Generic Radio Network Controller (GRNC)
This represents the RNC functions that are not covered by any of the other three types. This also relates to global functions such as transit or ATM functions.
Hard Handover
This is a category of handover procedures where all the old radio links in the UE are abandoned before the new radio links are activated.
Iu
Interface reference point between the RNS and the Core Network. (See also Iu-CS and Iu-PS.)
Iu-CS
Interface between the RNC and the circuit switched side of the Core Network, typically the MSC.
Iu-PS
Interface between the RNC and the packet switched side of the Core Network, typically the SGSN.
Iub
Interface between the RNC and the Node B. It is considered as a reference point.
Iur
Interface between two RNSs. While this interface logically represents a point to point link between RNSs, the physical realisation may not be a direct link. It is also considered as a reference point.
Node B Application Part (NBAP)
NBAP is used for setting up Radio Access Bearers (RAB) in the Radio Network Layer over the Iub.
Radio Access Network Application Part (RANAP)
Radio Network Signalling over the Iu.
Radio Network Subsystem Application Part (RNSAP)
Radio Network Signalling over the Iur between the SRNC and DRNC.
Serving Radio Network Controller (SRNC)
This represents the RNC functions that are used during an active call or data session.
Soft Handover
Soft handover is a category of handover procedures where the radio links are added and abandoned in such manner that the UE always keeps at least one radio link to the UTRAN. This typically involves multiple Node Bs.
Softer Handover
This is a type of soft handover that involves one or more cells of the same Node B.
Universal Mobile Telephone System (UMTS)
This represents the third generation mobile phone system that incorporates both Wideband CDMA for the FDD mode in the paired spectrum and Time Division – CDMA for the TDD mode in the unpaired spectrum.
