A Home Node B, or HNB, is the 3GPP's term for a 3G femtocell.
A Node B is an element of a 3G macro Radio Access Network, or RAN. A femtocell performs many of the function of a Node B, but is optimized for deployment in the home.
The following 3GPP documents are currently available:
Within an HNB Access Network there are three new network elements: the Home Node B (or femtocell), the Security Gateway (SeGW) and the Home Node B Gateway, or HNB-GW.
Between the HNB and the HNB-GW is a new interface known as Iu-h.
Home Node B (HNB) – Connected to an existing residential broadband service, an HNB provides 3G radio coverage for 3G handsets within a home. HNBs incorporate the capabilities of a standard Node B as well as the radio resource management functions of a standard Radio Network Controller RNC.
Home eNode B (HeNB) - Connected to an existing residential broadband service, an HeNB provides LTE radio coverage for LTE handsets within a home. HeNBs incorporate the capabilities of a standard eNodeB.
Security Gateway (SeGW) - Installed in an operator’s network, the Security Gateway establishes IPsec tunnels with HNBs using IKEv2 signaling for IPsec tunnel management. IPsec tunnels are responsible for delivering all voice, messaging and packet data services between HNB and the core network. The SeGW forwards traffic to HNB-GW.
HNB Gateway (HNB-GW) - Installed within an operator’s network, the HNB Gateway aggregates traffic from a large number of HNBs back into an existing core service network through the standard Iu-cs and Iu-ps interfaces.
Iu-h Interface - Residing between an HNB and HNB-GW, the Iu-h interface defines the security architecture used to provide a secure, scalable communications over the Internet. The Iu-h interface also defines an efficient, reliable method for transporting Iu-based traffic as well as a new protocol (HNBAP) for enabling highly scalable ad-hoc HNB deployment.