GSM Call Setup Communication Engineering GSM Call Setup

GSM Call Setup Communication Engineering

GSM Call Setup

AUC HLR • • BSC VMS EIR Pre. Paid Node MSC IN PSTN Fixed network SMSC INTERNET PSTN International PABX MSC • • BSC MS BTS BSC HLR MSC VLR AUC Mobile Station = phone + SIM card Base Transceiver Station Base Station Controller Home Location Register Mobile services Switching Centre Visitor Location Register Authentication Centre Stand-alone or integrated in HLR EIR Equipment Identity Register For blacklisting stolen and unwanted equipment SMSC Short Message Service ”Support” Centre VMS Voice Messaging System Pre. Paid Node Hosting prepaid service system IN Intelligent Network services PSTN Public Switched Telephone Network PABX Private Automatic Branch Exchange

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

BSC Base Station Controller • The call request reaches the BSC from the BTS and is forwarded to MSC. • After call is established, the BSC will perform decoding of the call (in typical config. )

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• Checks A number. • To whom is A subscriber calling? (Checks B number) • Example : A subscriber has GP prepaid. MSC Mobile Switching Centre

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

BSC VMS HLR EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• Does the A subscriber have money left on his/her account? • When the call is established and on-going the subscriber’s account is decremented accordingly. Pre. Paid Node

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail Pre. Paid MSC IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• • Where is the B subscriber? MSC interrogates in HLR. (HLR = Home Location Register) MSC Mobile Switching Centre

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• HLR says ’I am the home of the B subscriber and I know where he/she is right now’ (i. e. which VLR) • Tells this VLR ’Give me a visitor address for this subscriber’ (Roaming Number) HLR Home Location Register

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• Hosting MSC/VLR returns B subscriber’s assigned visitor address. MSC Mobile Switching Centre

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• ’Thanks for the visitor address!’ • ’I will send this address to the MSC that requested for it. ’ HLR Home Location Register

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• ’Thank you, HLR!’ • Speech connection is set up towards the MSC/VLR where the B subscriber is residing. MSC Mobile Switching Centre

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• Setting up a speech connection towards BSC. MSC Mobile Switching Centre

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• BSC will now send a paging signal to all the BTSs that it covers. • Coding of speech when call is established. BSC Base Station Controller

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

• The B subscriber has now many choices: • • • He/she may answer. He/she may be busy. The mobile (MS) may be forwarded. The mobile may be turned off or outside coverage area. And more. . . • What happens next depends on the B subscriber’s condition and what he/she chooses to do.

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC

HLR BSC VMS EIR Voicemail MSC Pre. Paid IN SMSC INTERNET MSC PSTN Fixed Network International PABX BSC