3G Protocol Stack - V2 26-08

3G – Protocol Architecture Amal Chandran

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

UMTS – Universal Mobile Telecom System PS Domain

3G-SGSN

3G-GGSN Gs

Inter-PLMN Backbone Network Iu-PS

3G-MSC CS Domain

Iu-CS

RNC Iur Node B Iub

Uu WCDMA

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

UTRAN

GSM/WCDMA Network Architecture

NAS 3G/WCDMA

MSC – Mobile Services Switching Centre GMSC – Gateway MSC HLR – Home Location Register RNC – Radio Network Controller Node B – WCDMA Base Station UTRAN – UMTS Radio Access Network 3

© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

2G/GSM

SGSN – Serving GPRS Support Node GGSN – Gateway GPRS Support Node BSC – Base Station Controller BTS – GSM Base Transceiver Station GERAN –GSM/EDGE Radio Access Network

Network Components • Node – B (BTS) : Physical Layer Device • RNC: Radio Network Controller • Controls the Node-B’s • MSC/GMSC: Mobile Switching Centre, Gateway MSC • Circuit Switched Services • VLR: Visitor Location Register • Database of Active Users in the area • HLR: Home Location Register • Subscriber Information • SGSN/GGSN: Serving GPRS Support Node, Gateway GSN • Packet Switched Services 4

© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

Protocol Stack – Review of Concepts • Software Architecture for enabling Communication • Each Layer has specific function Layer 3 message

Layer 2 Header L1 = Layer 1 Header

L1

L1

L1

Spreading, Scrambling, Modulation… 101010101000010101000010101010111010110101010......

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

Layer 1: The Physical Layer • Connects Node-B to UE • Cell Searching • Spreading • Scrambling • Modulation • Power Control • Measurements • Physical Channels of WCDMA

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

3G Network

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

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

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

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

Layer 3: RRC – The Brain 3G Network

• 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

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

Layer 3: Non Access Stratum • Mobility Management • Keeps track of Location Area • Call Management • Everything related to calls • Session Management • Data Connection management • SMS Services

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

User Data • PDCP • Packet Data Convergence Protocol • Header Compression • BMC • Broadcast and Multicast Control • Broadcast of information – Like “Tsunami Warnings”, “Traffic Alerts”

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

Powering up a mobile, in 3G • Search for cells • Find out the parameters of the cell from the information broadcast • Identify the Network ID (PLMN ID) of the network • Check the quality of the cell • Cell is good? • Setup a connection • Authenticate • Update the network with UE’s location information • Ready to go…

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

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

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

Change of Cells – Hand Over • Current cell quality is low • Move to another cell • Simultaneous reception from two (or more) Node-Bs • Soft Hand Over • Softer Handover

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

Soft/Softer handover RNC 2

RNC 1 (SRNC ) BTS 1

Sector 1

Setup call

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Sector 2

(DRN C)

Call transferred
Via SRNS relocation BTS 2

Sector 3

Sector 4

BTS 3

Sector 5

Sector 6

Add sector 6, Add SectorAdd 2 : Sector 3Add remove Sector : Sector 4,Add Sector 5, Softer 3 Soft Handover, remove Sector Remove sector remove Sector Handover same RNC 14, 2

© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

Triggers SRNS relocation

Overall Architecture TCP/IP Data – User Data

SM

MM

SMS

CM

SNDCP

User Data Non Access Stratum L3 GSM/GPRS

WCDMA

GPRS LLC RRC RR

L2

PDCP

GPRS RLC

GSM L2 WCDMA RLC

GPRS MAC L1

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WCDMA MAC GSM L1

© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

WCDMA L1

Interested in Reading Further? • Web: • http://www.3gpp.org/ • Look for Specification number 25.301 • http://www.etsi.org/

• Print Media • WCDMA For UMTS : Antti Toskala, Harri Holma

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© 2008 Nokia 3G Protocol Stack.ppt / 2009-08-26 / AC

THANK YOU ☺ Q&A? discussion.forum.nokia.com/vtuedusat

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