4 General description

23.1953GPPProvision of User Equipment Specific Behaviour Information (UESBI) to network entitiesRelease 5TS

4.1 UESBI

Due to the potential problems that may happen in the standard or in its implementation by different types of UE, it may be needed to transfer to the RAN "information on the specific behavior of particular sets of UE" with regard to some 3GPP features. This aims at helping the infrastructure to handle UE(s) already in the field that are facing problems to support some 3GPP features. This "information on the specific behavior of particular sets of UE" is called UE Specific Behavior Information (UESBI).

UESBI actually corresponds to 2 different sets of information:

  • UESBI-Uu which is sent from UE to RAN using signalling specified in the RRC protocol (TS 25.331 [6])
  • UESBI-Iu which is sent by CN to UTRAN/GERAN over the Iu interface and is derived from IMEISV retrieved by CN from UE.

UESBI-Uu and UESBI-Iu may have a different nature, their coding is defined in RRC and RANAP respectively, and have different handling within the network. Whether or not UESBI-Uu or UESBI-Iu is used to describe an inter-operability issue will be determined on a case by case basis and all uses should be documented in TRs such as 25.994 [13] and 25.995 [14]. As a result of this process, RAN nodes should not receive conflicting information in UESBI-Uu and UESBI-Iu.

The SRNC uses both UESBI-Iu and UESBI-Uu to derive the specific behaviour of the UE.

In the context of this specification, the terms RNS and RNC refer also to a GERAN BSS or BSC (respectively) when serving UE in Iu mode.

4.2 UESBI-Uu

UESBI-Uu information is sent:

– (at RRC connection establishment from idle mode) directly by UE to Serving RNC at RRC connection establishment

– (at SRNS relocation) from Serving RNC to Target RNC in the RRC: SRNS RELOCATION INFO message carried through CN during SRNS relocation in the RANAP: Source RNC to Target RNC Transparent Container IE.

– (at RRC connection establishment for an UE coming from another Radio Access Technology e.g. in case of 2G to 3G Hand-Over) from UE to Serving RNC via "Inter RAT Hand-Over" Information. This "Inter RAT Hand-Over Information" is sent to the source RAN (e.g. BSS), and at handover copied by the source RAN into a transparent container that is carried through the CN towards the Target RNC.

– (at RR connection establishment) the UE can directly send the "Inter RAT Handover Information" which contains the UESBI-Uu to the GERAN BSS. However, if control of GERAN BSS functions using the UESBI-Uu is needed, then new functionality will be required within the BSS to decode the ASN.1 PER information contained in the Inter-RAT Handover Information IE.

4.3 UESBI-Iu

When the UE attaches to the VLR or SGSN or makes its first Location Update in the VLR, the IMEISV information is retrieved from the UE and stored in the VLR or SGSN.

At each subsequent Iu interface connection establishment (eg for a CS domain voice call or a PS domain data transfer), the IMEISV is retrieved from the VLR or from the MM context in the SGSN and, the UESBI-Iu is derived. The UESBI-Iu is then sent to the SRNC. The UESBI-Iu is normally sent in the Common Id procedure (the same procedure that currently carries the IMSI) or by the UESBI-Iu Information procedure. This is summarised in figure 4.3-1.

Figure 4.3-1: UESBI–Iu architecture

If the UE state is changed from RRC Connected to RRC Idle, all information derived from the received UESBI is released in the RNS. Thus if the UE state is changed afterwards back to RRC Connected the delivery of the UESBI-Iu from MSC or SGSN to SRNC shall be repeated.

At inter-SRNS relocation or at inter-system handover, the anchor MSC (and not the source RAN node) sends the UESBI-Iu to the target RAN node.

4.4 UESBI-Iu on A interface

With GERAN, usage of UESBI is aimed to only solve issues related to CS domain GERAN to UTRAN handover. To smooth rollout of features, a Handover Reject cause is defined to provide minimal functionality (see clause 5.1.4.2).

Note: Currently no study has been performed on any need to influence the GPRS Cell Change Order to UTRAN procedure.