04-07-2012, 11:40 AM
3G – Protocol Architecture
3G – Protocol.pdf (Size: 713.02 KB / Downloads: 223)
Layer 1: The Physical Layer
• Connects Node-B to UE
• Cell Searching
• Spreading
• Scrambling
• Modulation
• Power Control
• Measurements
• Physical Channels of WCDMA
Layer 2: MAC
• Medium Access Control
• Provides Access to Layer 1.
• Priority Handling between the data flows of the UE
• Multiplexing of Logical Data (Logical Channels)
• Traffic Volume Monitoring
• Identification of UE on common channels
• Ciphering of Voice Data
Layer 2: RLC
• Radio Link Control
• Segmentation and Re-Assembly of data
• In-sequence delivery
• Error detection and recovery
• Flow control
• Ciphering of Control Data
• Three modes: Acknowledged, Unacknowledged, and Transparent
Layer 3: RRC – The Brain
• RRC : Radio Resource Control
•Management of Radio Resources
• Connection Management
• Setup, Maintenance, Release.
•Monitor the connection states
• Transfer of control messages
• Called “Signalling Messages”
• Control of 3G measurements
Incoming Call?
• Paging message
• UE’s ID is registered with the network now.
• Send out paging request to UE
• Identify the UE ID, and respond to the paging.
• Exchange call information –
• Codec to use, Quality (Data Rate) of the call etc.
• Setup the call
• Establish a dedicated connection