Enabling mobile operators to embrace the cost and performance advantages of broadband access networks.
At the request of mobile operators around the world, 3GPP (the international organization responsible for developing and maintaining technical specifications for 2G, 3G and 4G mobile networks) has developed a number of standards to enable mobile operators to deploy Smart Offload and Voice over LTE services.
3GPP GAN STANDARD Originally ratified into 3GPP Release 6, the Generic Access Network, or GAN, specification defines how all mobile circuit, packet and IMS-based services are extended over generic IP access networks like DSL and cable.
The GAN standard defines a network element called the GAN Controller (or GAN-C), which is deployed in the mobile operator's network. On one side, the GAN-C connects to an existing mobile core network as a standard BSC or RNC, through the well-defined 2G (A/Gb) and 3G (Iu-CS, Iu-PS) core network interfaces. On the other side, the GAN-C connects to the fixed broadband access network (e.g. the Internet). The interface between the GAN-C and a device with the GAN application software over the Internet is referred to as the "Up" interface. The Up interface, which is at the heart of the GAN standard, provides a secure, scalable method for transporting mobile signaling and bearer traffic over the Internet.
3GPP HNB (Femtocell) STANDARD Originally ratified into 3GPP Release 8, the Home NodeB (HNB) standard defines how 3G femtocells can be integrated back into the core mobile network. The standard is architecturally similar to the 3GPP GAN standard.
The HNB standard is based upon a network element call the HNB Gateway (HNB-GW), which is deployed in the mobile operator's network. On one side, the HNB-GW connects to an existing mobile core network as a standard RNC, through the well-defined 3G (Iu-CS and Iu-PS) core network interfaces. On the other side, the HNB-GW connects to the Internet. The interface between the HNB-GW and the HNB (or femtocell) over the Internet is referred to as the "Iu-h" interface. The Iu-h interface, which is at the heart of the upcoming HNB standard, defines a secure, scalable method for transporting mobile signaling and bearer traffic over the Internet.
VoLGA (Voice over LTE) SPECIFICATION In 2009, a number of leading mobile operators and equipment suppliers developed a set of specifications for delivering voice and SMS services over LTE. This effort, known as VoLGA (Voice over LTE Via Generic Access), is currently supported by the VoLGA Forum. VoLGA is a simplified version of the 3GPP GAN specification applied to an LTE access network.
VoLGA defines a network element called the VoLGA Network Controller (VANC), which is deployed in the mobile operator's network. On one side, the VANC connects to an existing mobile circuit core network as a standard BSC or RNC through the well-defined 2G (A) and 3G (Iu-CS) network interfaces. On the other side, the VANC connects to the mobile broadband (LTE) access network.
The interface between the VANC and the UE (handset...) over LTE is known as the "Z1" interface. The Z1 interface, which is at the heart of the VoLGA specification, defines a secure, scalable method for transporting mobile signaling and circuit bearer traffic over LTE. The Z1 interface is simply an "LTE optimized" version of the existing "Up" interface defined in GAN.
