5.11.3 Soft Handover between HNB and RNC via HNB-GW

25.4673GPPRelease 17Stage 2TSUTRAN architecture for 3G Home Node B (HNB)

5.11.3.1 Soft Handover from HNB to RNC

Mobility from HNB cells (hybrid or open access) to macro RNC using Soft Handover (SHO) follows the same principles as mobility between macro cells and uses an Iur interface established between HNB and macro RNC via the HNB-GW to support RNSAP signalling.

The HNB-GW acts as a single RNC towards the macro RNC (as it does towards the CN) and therefore acts as a concentrator for HNB-RNC connectivity via the HNB-GW.

For this case there is no involvement of the CN in the SHO operations, as there is no access control/membership verification needed for SHO to a macro RNC.

The HNB acts as a SRNC and requests resources from the macro RNC, however this may happen only in case of HNBs deployed in a secure and operator controlled way (coordinated deployment) and, in this case, it is managed by the CAC of the DRNC.

Figure 5.11.3.1-1 shows the sequence of messages involved.

Figure 5.11.3.1-1: Soft Handover HNB to RNC via HNB-GW.

1. HNB determines that a RL can be established to a macro RNC cell.

2-7. Normal RL setup procedure between HNB and RNC via the HNB-GW.

5.11.3.2 Soft Handover from RNC to Open or Hybrid Access HNB

Mobility from macro cells to Open or Hybrid Access HNB cells using Soft Handover follows the same principles as mobility between macro cells and uses an Iur interface established between the HNB and the macro RNC via the HNB-GW to support RNSAP signalling.

The HNB-GW acts as a single RNC towards the macro RNC (as it does towards the CN) and therefore acts as a concentrator for HNB-RNC connectivity via the HNB-GW.

For this case of open or hybrid access HNB, there is no involvement of the CN in the SHO operations. For the case of SHO to hybrid access HNB, if supported, the Radio Link is established assuming the UE is non-member.

The macro RNC acting as SRNC requests resources from the HNB, it is managed by the CAC of the HNB.

Figure 5.11.3.2-1 shows the sequence of messages involved.

Figure 5.11.3.2-1: Soft Handover from RNC to Open or Hybrid Access HNB via HNB-GW.

1. RNC determines that a RL can be established to a HNB cell.

2-7. Normal RL setup procedure between RNC and HNB via the HNB-GW. For Hybrid cells, if supported, the Radio Link is established assuming the UE is a non-member.