R adio S - pudn.comread.pudn.com/downloads161/ebook/733566/GPRS/cd... · : Medium Access Control Convergence Protocol GTP: GPRS Tunnelling Protocol RLC: Radio Link Control TCP: Transmission

GPRS General Packet Radio ServicesProtocol layers inside the mobile station

1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

1

General Packet Radio ServicesGPRS

Protocol layers inside the MS


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

2

Your Lecturer is:

Reiner StuhlfauthRohde&Schwarz

Training Center, Munich


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

3

Structure of presentation

� GPRS - Transmission Plane

� GPRS - protocol: SNDCP

� GPRS - protocol: LLC

� GPRS - protocol: RLC/MAC

� Protocol aspects

Outline of Presentation


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

4

GPRS - ProtocolsWhy protocols?

Signalling plane:• Communication between network elements

• Establish, maintain and terminate a connection

Transmission plane:Packet data transport

Segmentation + concatenationEncapsulationError protection + correctionCipheringData flow + sequence control


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

5

GPRS Transmission Planes

MAC

GSMRF

RLC

LLC

SNDCP

IP/X.25

MAC

GSMRF

RLC

FR

L1bis

BSSGP

Relay

FR

L1bis

BSSGP

LLC

SNDCP

L1

L2 L2

IP IP

UDP /TCP

UDP /TCP

GTP GTPRelay

IP/ X.25

MS BSS SGSN GGSNUm Gb Gn Gi

L1

BSSGP : BSS GPRS Protocol LLC : Logical Link Control SNDCP : SubNetwork DependentFR: Frame Relay MAC : Medium Access Control Convergence ProtocolGTP : GPRS Tunnelling Protocol RLC : Radio Link Control TCP : Transmission Control Protocol IP: Internet Protocol UDP : User Datagram Protocol

L2‘

IP/ X.25

L1‘

Relay

L2‘

IP/ X.25

L1‘

L2‘

IP/ X.25

L1‘

Relay

Application/ Higher level protocols

Rou-ter

GPRS Protocol Planes


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

6

GPRS Transmission Planes

MAC

GSMRF

RLC

LLC

SNDCP

IP/X.25

MAC

GSMRF

RLC

FR

L1bis

BSSGP

Relay

FR

L1bis

BSSGP

LLC

SNDCP

L1

L2 L2

IP IP

UDP /TCP

UDP /TCP

GTP GTPRelay

IP/ X.25

MS BSS SGSN GGSNUm Gb Gn Gi

L1


L2‘

IP/ X.25

L1‘

Relay

L2‘

IP/ X.25

L1‘

L2‘

IP/ X.25

L1‘

Relay


Rou-ter

GPRS Protocol Planes

GPRS specifies acomplete IP-basedbackbone network


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

7

Relay

NetworkService

GTP

Application

IP

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

Relay

L2

L1

IP

L2

L1

IP

GTP

IP

Um Gb GnMS BSS SGSN GGSN

NetworkService

UDP /TCP

UDP /TCP

GPRS-Transmission PlaneGPRS = Bearer Service for IP-based data

Inside the mobile station, the highest layerInternet Protocol forms the interface to allof the applications

PDN


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

8

MAC

GSMRF

RLC

LLC

SNDCP

IP/X.25

MAC

GSMRF

RLC

FR

L1bis

BSSGP

Relay

FR

L1bis

BSSGP

LLC

SNDCP

L1

L2 L2

IP IP

UDP /TCP

UDP /TCP

GTP GTPRelay

IP/ X.25

MS BSS SGSN GGSNGb Gn Gi

L1


L2‘

IP/ X.25

L1‘

Relay

L2‘

IP/ X.25

L1‘

L2‘

IP/ X.25

L1‘

Relay


Rou-ter

GPRS Protocol PlanesProtocol layers insidethe mobile station


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

9

SNDCP = SubNetwork Dependent Convergence Protocol LLC = Logical Link Control

Um

Network

SNDCP

LLC(Note)

RLC

MAC

Phys. Link

Phys. RF

SNDCP

LLC

RLC

MAC

Phys. Link

Phys. RF

MS

Maps network level characteristics onto

characteristics ofunderlying protocols

Logical Link between MS and SGSN. Data transportindependentfrom the Radio Interface

RLCReliable link + Radio Link Controlfunctions

MACAccess Control signalling+Mapping of LLC-Framesonto physical channels

Data Coding, Burst Forming,Interleaving, ConvolutionalCoding = Error protection

Modulation, Timingand RF-Generation

RLC = Radio Link ControlMAC = Medium Access Control

GPRS Protocol Planes inside MS


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

10


NetworkMSRLC = Radio Link ControlMAC = Medium Access Control


Um

SNDCP

LLC(Note)

RLC

MAC

Phys . Link

Phys . RF

SNDCP

LLC

RLC

MAC

Phys . Link

Phys . RF


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

11

GPRS-Protocols: SNDCP

RLC

MAC

Relay

NetworkService

GTP

Application

IP / X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bisGSM RF

BSSGP

L1bis

Relay

L2

L1

IP

Um GbMS BSS SGSN

NetworkService

UDP /TCP

Subnetwork Dependent Convergence Protocol, SNDCPPosition of SNDCP in the protocol stack


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

12

SNDCP - Functions:

•Compression

•Segmentation and Concatenation

•Multiplexing



1MAT | 10.09.02 |

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SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

13

LL 5 LL 9LL 3 LL 11

5 6

LLC

15NSAPI

SAPI

. . .

Protocolcompr.

7

Datacompr.

Datacompr.

8

PDP

Protocolcompr.

Datacompr.

Protocolcompr.

SNDCP users

SNDCP: Compression of Protocol header and/or Data

Various waysof compression

PDPPDPPDP

SNDCP



1MAT | 10.09.02 |

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SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

14

NSAPI:Identifies Application SNDCP

Packet DataProtocol

LLC

NSAPI N-PDU

SAPISN-PDU

Packet DataProtocol

Packet DataProtocol

. . .

Subnetwork Dependent Convergence Protocol, SNDCP

- Multiplexing- Segmentation + Concatenation- Data Compression

Multiplexing of different applications:


Corresponding to thevarious applications


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

15


NetworkMSRLC = Radio Link ControlMAC = Medium Access Control


Um

SNDCP

RLC

MAC

Phys . Link

Phys . RF

SNDCP

LLCRLC

MAC

Phys . Link

Phys . RF

LLC


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

16

Logical Link Control, LLC: Characteristics

•Data transfer to different MS‘s

•Provides data transport for different Layer-3 sublevels

•Provides one or more logical links to 1 MS

•Sequence Control

•Error protection and error correction

•Data Flow Control

•Ciphering

GPRS-Protocols: LLC


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

17

GPRS-Protocols: LLCLogical Link Control: LLC

Um GbMS SGSN

SNDCP SMSGMM

LLC

RLC

MAC

GSM RF

LLC

BSSGP

NetworkService

L1

TOM SNDCP SMSGMMTOM

Data transport for various protocol layers between MS and SGSN

BSS

Relay

RLC

MAC

GSM RF

BSSGP

NetworkService

L1


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

18

GPRS-Protocols: LLC

SGSNMS

GPRS Mobility Management SNDCP SMS

RLC/MACRLC/MAC layerLLC layer

Layer 3

LLC layer

BSSGPBSSGP layer

TOM

Logical Link Control, LLC: Interfaces to other protocol layers

LLGMM LLGMM LL3 LL5 LL9 LL11 TOM1 TOM2 LLSMS

GRR BSSGP

LLC protocol entity

Layer 3 signaling formobility management

and session management

User data applications

Tunneling offoreign signaling

SMS viaGPRS


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

19

GPRS-Protocols: LLCLogical Link Control, LLC: Frame Format

8 7 6 5 4 3 2 1Bit

Address Field

Control Field

Information Field

Frame CheckSequence

1 octet

Max. 36 octets

Max N201octets

3 octets

Contains SAP

Identifies U, S, Iand UI-Frames

Contains dataof upperlayer protocols

Used for Error detection


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

20

GPRS-Protocols: LLC

GPRS Mobility Management SNDCP SMSLayer 3

LLC layer

TOM

LLGMM LLGMM LL3 LL5 LL9 LL11 TOM1 TOM2 LLSMS

LLC protocol entity

LLC Frame: Address FieldOctet

1

8 7 6 5 4 3 2 1

SAPI

Bit

PD C/R X X

Used to define the Service AccessPoints between LLC and higher layers


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

21

GPRS-Protocols: LLC

I-format N(S) XA

N(R) S1 S2

0 N(S)X

N(R)

123

Control Field Bits2 14 3568 7 Octet

1 A

N(R)

0

S2S1

X X N(R) 1

2S-format


1 0

N(U)

1

PME

X X N(U) 1

2UI-format


1 11 M1M2P/F M4 1U-format


M3

LLC: Control Field Format

Information framefor acknowledged data transfer

Supervisory framefor acknowledgement andlink status information

Unnumbered Information frame for unacknowledged data transfer

Unnumbered framefor signalling between LLC entities


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

22

BSS = Base Station Subsystem

Um

BSS

RLCMAC

Phys. Link

Phys. RF

SNDCP

LLC

RLCMAC

Phys. Link

Phys. RF

MS

RLCReliable link + Radio Link Controlfunctions

MACAccess Control signalling+Mapping of LLC-Framesonto physical channels

Data Coding, Burst Forming,Interleaving, ConvolutionalCoding = Error protection

Modulation, Timingand RF-Generation

RLC = Radio Link ControlMAC = Medium Access Control

GPRS Protocol Planes inside MSLower layer protocols: RLC/MAC + Physical Interface


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

23

GPRS Physical LayerPhysical Link Layer - tasks:

•Block Coding•Forward Error Correction, FEC•Interleaving•Congestion Control on Air interface•Synchronisation, Timing Advance•Signal Quality Estimation•Signal Level Estimation•Transmitting Power Control•Burst Generation

=> No bigdifferences to GSM-physical layer!


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

24

LLClayer

RLC/MAClayer

Physicallayer

RLCblocks

LLCframe FH Informationfield FCS

Normal burst Normal burst Normal burst Normal burst

Primary

block

Following

block

BHInfo field

BH BCS Info field

BCS Info field

BH BCS

FH = Frame HeaderFCS = Frame Check Sequence

BH =BCS = Block Check Sequence

Block Header

LLC-Frame, RLC/MAC-Block and Burst Forming

GPRS Protocols: RLC/MAC


1MAT | 10.09.02 |

TransmissionPlane

SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

25

Channel Coding

Scheme Code rate

USF Pre-coded USF

Radio Block

USF and BCS

BCS Tail Codedbits

Puncturedbits

Data ratekb/s

CS-1 1/2 3 3 181 40 4 456 0 9.05

CS-2 ≈≈≈≈2/3 3 6 268 16 4 588 132 13.4

CS-3 ≈≈≈≈3/4 3 6 312 16 4 676 220 15.6

CS-4 1 3 12 428 16 - 456 - 21.4

GPRS: Coding Schemes CS-1 up to CS-4

excl.


1MAT | 10.09.02 |

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LLC-protocol

RLC/MAC-protocol

Protocol aspects

26

Channel Coding

Scheme Code rate USF Pre-codedUSF

RadioBlock

excl. USFand BCS

BCS Tail Codedbits

Puncturedbits

Data ratekb/s

CS-1 1/2 3 3 181 40 4 456 0 9.05CS-2 ≈2/3 3 6 268 16 4 588 132 13.4

CS-3 ≈3/4 3 6 312 16 4 676 220 15.6

CS-4 1 3 12 428 16 - 456 - 21.4

Total bits with CS-1: 3 + 181 + 40 +4 = 228bit

228 bit with code rate 1/2 => 456 bit


1MAT | 10.09.02 |

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SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

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Channel Coding

Scheme Code rate USF Pre-codedUSF

RadioBlock

excl. USFand BCS

BCS Tail Codedbits

Puncturedbits

Data ratekb/s

CS-1 1/2 3 3 181 40 4 456 0 9.05

CS-2 ≈≈≈≈2/3 3 6 268 16 4 588 132 13.4CS-3 ≈3/4 3 6 312 16 4 676 220 15.6

CS-4 1 3 12 428 16 - 456 - 21.4

Total bits with CS-2: 6 + 268 + 16 +4 = 294bit

294 bit with code rate 1/2 => 588 bitBut 588 bits do not fit into 1 Radio Block (size = 456 bit)=> Puncturing of 132 bits


1MAT | 10.09.02 |

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SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

28

RLC DataRLCHeader BCSUSF

MAC-HeaderUSF

Convolutional Coding

Puncturing

456 Bit

57 Bit 57 Bit 57 Bit 57 Bit 57 Bit 57 Bit 57 Bit 57 Bit

Burst Forming

Radio Blocknetto

Channelcoding

Radio Block= 4 Bursts

GPRS Radio Block Construction


1MAT | 10.09.02 |

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LLC-protocol

RLC/MAC-protocol

Protocol aspects

29

downlink

USFRadio Block B(n)

USF = R1

USF = R2

USF = R3

USF = Free

USF = FreeMonitoring Paging ChannelSend Access Burst

uplink

Radio Block B(n+1)

Monitoring USF in Block B(n)Sends in Block B(n+1) or in Blocks B(n+1) - B(n+4)

Fixed Allocation = Fixed number of Radio Blocks to be transmitted in N bundled Timeslots

Dynamic Allocation = USF points to next Radio Blockon uplink RF-Channel for use by MS

Extended Dynamic Allocation = USF allows the usage of Radio Blocks on all higher timeslots

GPRS Dynamic Assignment with USFUSF = Uplink State Flag


1MAT | 10.09.02 |

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SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

30

RLC/MAC Block Structure

RLC DataMACHeader

RLCHeader BCS

RLC/MAC block structureRLC/MAC block structure

Radio Block structure for data transfer

RLC/MAC Control MessageMACHeader BCS

Radio Block structure for control message


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LLC-protocol

RLC/MAC-protocol

Protocol aspects

31

RLC/MAC Block Structure

Differences in Block Structure

RLC/MAC - Block

Data Transfer Signalling

Downlink Uplink Downlink Uplink

•MAC-Header•RLC-Data Block

•MAC-Header•RLC-Data Block

•MAC-Header•RLC/MAC - Control Block

•MAC-Header•RLC/MAC-Control Block

1 Radio Block is the smallest Data Transport Unit in GPRS!


1MAT | 10.09.02 |

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LLC-protocol

RLC/MAC-protocol

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32

GPRS protocols: RLC/MAC

Bit

Payload Type RRBP USFS/P MAC Header

12345678

MAC-Header data transfer in downlink direction

Distinguishesbetween dataor signaling

Points to next user of uplink

resources

Polling of uplink signaling

messages

SwitchesRRBP field

on or off


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Octet N

Payload Type Countdown Value SI MAC Header

Bit

12345678

R

MAC-Header data transfer in uplink direction

Distinguishesbetween dataor signaling

Indication ofuplink

termination by counting down


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Data or SignallingMACHeader

RLCHeader BCS

Contains:Temporary Flow Identifier, TFIBlock Sequence NumberLength field,etc.

RLC-Header format


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35


RLC/MAC Control MessageMACHeader

Radio Block structure for control message

RLC/MAC block

RLC control block

Control Header

RLC/MAC - Block for Signalling


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LLC-protocol

RLC/MAC-protocol

Protocol aspects

36


GRR Signalling Messages on Downlink(Via RLC/MAC)

Downlink Messages

• Packet Access Reject• Packet Cell Change Order• Packet Downlink Assignment• Packet Paging Request• Packet PDCH Release• Packet Polling Request• Packet Power Control/Timing Advance• Packet PRACH Parameters• Packet Queuing Notification• Packet Timeslot Reconfigure

•Packet TBF Release•Packet Uplink Ack/ Nack•Packet Uplink Assignment•Packet Downlink Dummy Control Block•Packet System Information Type 1•Packet System Information Type 2•Packet System Information Type 3

•Packet System Information Type 4•Packet System Information Type 5•Packet System Information Type 13


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37


GRR Signalling Messages on Uplink (Via RLC/MAC)

• Packet Cell Change Failure• Packet Control Acknowledgement• Packet Downlink Ack/Nack

•Packet UplinkDummy Control Block• Packet Measurement Report• Packet Resource Request• Packet Mobile TBF Status (SMG #30+)• Packet PSI Status (SMG #30+)

•


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LLC-protocol

RLC/MAC-protocol

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38

GPRS protocols: General aspects

Identification of a logical link between network and MS

DLCI = SAP + TLLI

Temporary Logical Link Identifier

Service Access Point

Identifies upper or lower layer , i.e.:

GMM , SNDCP , TOM,SMS, RLC/MAC, BSSGP

Data Link Connection Identifier

Identifiespeer to peerconnection

In LLCheader

Identifies MSIncluded in RLC/MACheader


1MAT | 10.09.02 |

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39

GPRS protocols: General aspects

TLLI orTFI

SAPI NSAPIRF

RLC/MAC

LLC

SNDCPTOM SMS SM/GMM

SAPI

PDP PDP PDP

NSAPI

IdentifiesMS

Identifies Layer 3 Protocol

Identifies PDP - context

Cascaded identifiers


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LLC-protocol

RLC/MAC-protocol

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40

Protocol layers inside MS:Data

TCP/IP

SNDCP

Information fieldLLC FCS

Data fieldRLC/MAC BCS

456 bit

Max length = 1600 octets

184 - 440 bit, depending on CS-1 - CS-4

Application

IP

SNDCP

LLC

RLC/MAC = new data

= previouslayerRF

Convolutional encoding

GPRS Protocols: General aspects

16 or 40 bit, depending on CS

CS = Coding Scheme, BCS = Block Check Sequence, FCS = Frame Check Sequence


1MAT | 10.09.02 |

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SNDCP-protocol

LLC-protocol

RLC/MAC-protocol

Protocol aspects

41

Thank you for your attention

??

http://www.rohde-schwarz.comor

[email protected]

Further questions:

?

Documents

R adio S - pudn.comread.pudn.com/downloads161/ebook/733566/GPRS/cd... · : Medium Access Control Convergence Protocol GTP: GPRS Tunnelling Protocol RLC: Radio Link Control TCP: Transmission