30-06-2012, 05:27 PM
Call Establishment
[attachment=26370]
Introduction
In AMPS ,many handshaking functions (BS,MS&MSC ) to complete the call setup
With N/w elements & databases of digital wireless n/w’s – introduced
Traffic cases: Various voice calls &data services
Depending –traffic situation- Mobility &
Connection Management –maintained the radio link
Management functions –Network layer
Messages b/w RBS,BS & MSC –Datalink layer
Type of radio signals,Modulation& timing specifications used by MS & RBS –Physical Layer
Mobile terminated call
#1: Any call from PSTN to mobile –routed –GMSC
#2: When Mobile system detects call at GMSC-
system –determine location of MS.
GMSC –check the MSISDN no –find out which HLR the subscriber reg. in
#3 Using SS7,MSISDN –forwarded-HLR –request for routing information –set up call
HLR -which MSC/VLR serves MS & HLR –messages to appr.MSC – temp. MSRN –route
MSRN –not stored in HLR
#4 MSRN –created –sent to HLR
#5 MSRN sent back – GMSC
#6 Using MSRN –GMSC routes –call to MSC/VLR
#7 When serving MSC receives call – uses MSRN to retrieve MSISDN no. Temp MSRN –released
#8 MSISDN – MSC/VLR –find LAI
#9 MS paged in all cells –have that have LAI
#10 When MS responds –auth.& encrp. –confirmed-call connected -MSC to BSC to RBS-TCH assigned.
[attachment=26370]
Introduction
In AMPS ,many handshaking functions (BS,MS&MSC ) to complete the call setup
With N/w elements & databases of digital wireless n/w’s – introduced
Traffic cases: Various voice calls &data services
Depending –traffic situation- Mobility &
Connection Management –maintained the radio link
Management functions –Network layer
Messages b/w RBS,BS & MSC –Datalink layer
Type of radio signals,Modulation& timing specifications used by MS & RBS –Physical Layer
Mobile terminated call
#1: Any call from PSTN to mobile –routed –GMSC
#2: When Mobile system detects call at GMSC-
system –determine location of MS.
GMSC –check the MSISDN no –find out which HLR the subscriber reg. in
#3 Using SS7,MSISDN –forwarded-HLR –request for routing information –set up call
HLR -which MSC/VLR serves MS & HLR –messages to appr.MSC – temp. MSRN –route
MSRN –not stored in HLR
#4 MSRN –created –sent to HLR
#5 MSRN sent back – GMSC
#6 Using MSRN –GMSC routes –call to MSC/VLR
#7 When serving MSC receives call – uses MSRN to retrieve MSISDN no. Temp MSRN –released
#8 MSISDN – MSC/VLR –find LAI
#9 MS paged in all cells –have that have LAI
#10 When MS responds –auth.& encrp. –confirmed-call connected -MSC to BSC to RBS-TCH assigned.