Radio access network

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A radio access network (RAN) is part of a mobile telecommunication system. It implements a radio access technology. Conceptually, it sits between the mobile phone, and the core network (CN). The mobile phone is varyingly known as user equipment (UE), terminal equipment, mobile station (MS), etc., depending on the standard. See the following diagram:

     CN
    /  \
   /    \
 RAN    RAN
 / \    / \
UE UE  UE UE

Examples of radio access network types are:

• GRAN - GSM radio access network
• GERAN - GERAN radio access network, essentially the same as GRAN but specifiying the inclusion of EDGE packet radio services
• UTRAN - UMTS radio access network

The term RAN is typically used in regards to the GSM, UMTS, and associated family of standards. While there is no direct equivalent in TIA standards such as IS-136 and IS-95, the equivalent would be the air interface of that network, coupled with those components governing the networking of base stations and their connection to the core network.

Note that it is also possible for a single handset/phone to be simultaneously connected to multiple radio access networks. Handsets capable of this are sometimes called dual-mode handsets. For instance it is common today (2006) for handsets to support both GSM and UMTS (a.k.a. "3G") radio access technologies. It is then possible to seamlessly transfer an ongoing call between different radio access networks without the user noticing any disruption in service.