DL - 4G Americas

Figure B.14. E-UTRAN HeNB Logical Architecture (based on 3GPP TS 23.830).
The first variant shown in Figure B.15 has a dedicated Home eNodeB Gateway (HeNB GW) and is very
similar to the Home NodeB architecture for UMTS-HSPA. The second variant shown in Figure B.16 does
not have a HeNB GW but assumes the concentration functions and SeGW functions are either in
separate physical entities or co-located with existing entities (e.g. the MME and/or SGW). The third
variant shown in Figure B.17 is a hybrid of the first two where there is a HeNB GW but only for the control
plane.
Rel-8 focused mainly on defining idle mode mobility procedures related with Closed Subscriber Group
(CSG, i.e. a group of users authorized to access a particular HNB or HeNB). In particular, Rel-8
addressed CSG reselection and manual CSG selection. The main objectives for work on HNBs and
HeNBs in Rel-9 is to build on the foundations from Rel-8 and add further functionalities that will enable
the mobile operators to provide more advanced services as well as improving the user experience. Of
particular focus are enhancements to the existing Rel-8 idle mode mobility mechanisms, to provide active
mode mobility support, specifically in the following features:
� LTE Macro to UTRA HNB Handover
� LTE Macro to HeNB Handover
� Inter-PLMN Manual CSG Selection
� Hybrid/Open Access Mode
The Rel-9 enhancements will be defined as such that legacy mechanisms coexist with the concepts
introduced to ensure pre-Rel-9 mobiles will be supported.
www.4gamericas.org February 2011 Page 140