HeNB Subsystem is defined in TS 23.401
. According to the definition, a HeNB Subsystem consists of a HeNB and optionally a HeNB GW. The HeNB Subsystem is connected by means of the standard S1 interface to the EPC (Evolved Packet Core), more specifically to the MME (Mobility Management Entity) by means of the S1-MME interface and to the Serving Gateway (S-GW) by means of the S1-U interface.
Detailed functions of HeNB and HeNB GW are described in TS 36.300
. To be more specific, HeNB is a Customer Premise Equipment that offers the LTE-Uu Interface to the UE. And it could discovery a suitable Serving HeNB GW over S1 interface. A HeNB GW can relay UE-associated S1 application part messages between the MME serving the UE and the HeNB serving the UE. It could terminate non-UE associated S1 application part procedures towards the HeNB and towards the MME and optionally terminate S1-U interface with the HeNB and with the S-GW.
Based on the above characteristics, this specification defines respective HeNS NRM IRP requirements.
The following general and high-level requirements apply for the present IRP:
The NRM defined by this IRP:
Shall support communications for telecommunication network management purposes, including management of converged networks.
Is a member of the Federated Network Information Model (FNIM)  and its information is derived from FNIM Umbrella Information Model (UIM) 
In addition to the above, the following more specific requirements apply:
The Network Resource Model defined by this IRP shall contain HeNB GW specific IOCs and related definitions.
The Network Resource Model defined by this IRP shall provide support for enabling consistency between HeNB GW, HeNB and related EPC nodes.