BTS: Base Transceiver Station

BSC: Base Station Controller

MSC: Mobile Switching Center

DMH: Data Message Handler

OMC: Operation Maintenance center

LWF: Interworking Function

HLR: Home Location Register

VLR: Visitor Location Register

AUC: Authentication Center

ELR: Equipment Identity Register

Other than radio interface the remaining network is similar to GSM

MS: Mobile unit with user

BSS: Manages radio interface b/w mobile stations and MSC consists of BTS and BSC.

MSC: Central unit equivalent to telephone exchange in a fixed network.

Functions:

1. Anchor MSC: Radio contact
2. Border MSC: Control BTS adjacent to location of mobile station
3. HLR: maintains all subscriber related info and is responsible for managing mobile subscribers. Multiple MSCs are served by HLR
4. DMH: collecting billing data
5. VLR: linked to one or more MSCs. Dynamically stores subscriber information obtained from subscribers HLR data. During roaming MS enters a new service area covered by MSC. MSC informs associated VLR about the MS querying the HLR after MS goes through a registration process.

6. AUC: manages Authentication

7. ELR: Provides information about mobile device for record purposes

8. OMC: overall management of wireless network

9. LWF: enables msc to communicate with other networks.