A Public Land Mobile Network (PLMN) is uniquely identified by the combination of a mobile country code and a mobile network code (the PLMN-Id). Sharing of radio resource and network nodes requires a PLMN network to support more than one than one PLMN-Id.
GPP defines two different configurations for supporting network sharing based on the resources being shared.
Gate Core Network (GWCN) Configuration
In this configuration, the radio access network and some core network services are shared among different operators. Each operator has its own network node for GGSN, HLR etc, while sharing SGSN and MSC with the rest of the radio network. The figure below depicts a GWCN configuration.
Multi Operator Core Network (MOCN) Configuration
In this configuration, the radio network is shared among different operators, while each operator maintains its separate core network. The figure below depicts a MOCN configuration.
Relationships to Other Features
SGSN supports both MOCN and GWCN in 3G. GPRS. The MOCN feature can work with 3G network sharing. Inter-RAT from 3G to 2G in shared to non-shared area, and non-shared area to shared are supported.
To enable GPRS MOCN, the BSC also needs to support the GPRS MOCN. For "Supporting-MS", the MS shall have the capability to select the network from the PLMN details shared by the BSC. Currently, the SGSN supports only "non-supporting MS", thus the MS always selects the common PLMN.