The document compares the call flow processes in GSM and UMTS networks. In GSM, call setup involves locating the mobile station, initiating the call on control channels, performing measurements and filtering, assigning radio channels, and network functions like handover and call supervision on traffic channels. In UMTS, call setup activates power control algorithms on signaling channels, establishes a radio access bearer through predefined signaling and measurements, assigns dedicated channels, and uses soft handover and power control functions on those channels for call supervision.

1. Call Flow
A comparison between the call
flow in GSM and UMTS

2. GSM Call Flow Call to a MS Call from a MS
Locating
on (Paging Perf.)
Initiations
CCCH/ Paging on
PCH (Random Access) RACH
Filtering MEASUREMENTS
•Immediate
(SDDCH Perform.)
Channel Administration
on Assignment
Urgency Immediate Immediate assignment on TCH
CCCH/ Assignment •ACLC
AGCH of SDCCH
Basic Ranking
Aux Radio (Available TCH) •ASSOC
Network
on Assignment / •AW
SDCCH Assignment of TCH
Function Eval Change of •CLS
(HCS) (Assignment Fail.) •DHRA
Mode
Organizing List (Traffic Erlangs)
on (Call Quality)
Sending List TCH
Supervision
Handover
•Inter cell/BSC
•Intra cell/BSC
Allocation Reply (Handover Perf.) •OL/UL
•Bad Quality
Handover/Clear (Dropped Calls) •Urgency
•HCS

3. UMTS Call Flow Call to a MS Call from a MS
Activate
Algorithms on (Paging Perf.)
PICH/ Paging on Open Loop
SCCPCH (Random Access) RACH Power Control
Power Ctrl.
•Directed Retry
(RRC Connect. Perform.)
on FACH/ RRC
Code Ctrl. Predefined Signaling
Inner Loop/Outer Loop
SCCPCH Connection
RAB Selected
Admission Ctrl.
MEASUREMENTS
(Available TCH) •Load Sharing
on FACH/
RAB Selection SCCPCH RAB Assignment of DPDCH
Power Control
Assignment (RAB Establish. Fail.)
(Traffic Erlangs)
on (Call Quality)
DPDCH
Supervision
Soft Handover
(Throughput) •Inter cell/BSC
•Intra cell/BSC
(Handover Perf.) •OL/UL
Soft/Softer •Bad Quality
Handover/Clear (Dropped Calls) •Urgency
•HCS

5. Open Loop on Access Channel