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2 MAR | Re |08/00 |
1 1 GPRS General Packet Radio ServicesAir interface aspects
1MAT | 09.09.02 |
GPRSGeneral Packet Radio Services
(Placeholder for a cover picture; this picture should alwayscover the whole slide width as shown here)
GPRS Air Interface aspects
GPRS General Packet Radio ServicesAir interface aspects
1MAT | 09.09.02 |
GPRSPhysical resource
GPRSLogical channels
GPRSAllocation ofphysical resource
2
Your Lecturer is:
Reiner StuhlfauthRohde&Schwarz
Training Center, Munich
GPRS General Packet Radio ServicesAir interface aspects
1MAT | 09.09.02 |
GPRSPhysical resource
GPRSLogical channels
GPRSAllocation ofphysical resource
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Structure of presentation
�GPRS - Physical resource
�GPRS - Logical channels
�GPRS - Allocation of physical resource
Outline of Presentation
GPRS General Packet Radio ServicesAir interface aspects
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GPRSPhysical resource
GPRSLogical channels
GPRSAllocation ofphysical resource
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GPRS Radio Interface GPRS-Burst-Types
Abbreviations :T=Tail Bit (3 Bits/ 8 Bits in leading part of Access BurstF=Flag (1 Bit)G=Guard Period (8,25 Bits/ 68,25 Bits in Access Burst)
T3
T3
T3
T3
T3
T3
T3
T3
T8
57 data bits 57 data bits 26 BitsTraining Sequence
F1
F1 G
8,25
G8,25
G8,25
G8,25
G68,25
142 fixed Bits
64 BitsExtended Training Sequence39 data bits 39 data bits
142 fixed Bits
36 data bits T3
41 BitsTraining Sequence
Normal Burst
Frequency Correction Burst
Synchronisation Burst
Dummy Burst
Access Burst
GPRS uses thesame Burst types asknown from GSM
GPRS General Packet Radio ServicesAir interface aspects
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GPRS Radio Interface: Common Features to GSM
•GPRS needs Circuit Switched Signalling:FCCH, SCH and BCCH
•GPRS uses GSM Normal Burst for data transport:
•GPRS uses same Modulation: GMSK
TInformation F GInformationFTrainings- sequence
3 57 1 26 31 57 8,25T
T = Tailbits F = Flagbits G = Guardtime
GPRS Radio Interface
GPRS General Packet Radio ServicesAir interface aspects
Capacity on demand: Provides circuit switchedchannels and packet switched channels in a dynamicmanner
Example: Cell with 1 Frequency channel: 1 physical channel for signalling, 4 physical channels for circuit switched TCHand 3 physical channels for packet switched PDCH
GPRS Capacity on Demand
GPRS General Packet Radio ServicesAir interface aspects
1 Radio Blockis the smallesttransport unitin GPRS!
2 Radio Blocksmay belong to 2 different users!=> sharing of physical resources
Radio Block transmits signalling or data
GPRS General Packet Radio ServicesAir interface aspects
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GSMPhysical resource = 1 Timeslot on 1 Frequency Channel
e.g. ARFCN + TN
GPRS, using Temporary Block Flow to identify radio resourcePhysical resource = N Radio Blocks (=4 Normal Bursts) on 1 or more Timeslots. Temporary Block Flow, TBF identifies allocated physical resource
Allocation of physicalresource
Downlink Uplink
Symmetric data transfer
Downlink Uplink Downlink Uplink
Symmetric data transfer Asymmetric data transfer
fixed
dynamic
Extended dynamic
or
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4
downlink
uplink
GPRS Physical Resource
GPRS General Packet Radio ServicesAir interface aspects
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GPRS Physical Resource
TBF:A Temporary Block Flow is a physical connection usedby two entities to transport Packet Data Units on a packet data physical channel.
TFI:A Temporary Flow Identifier is assigned to every TBF. The TBF is identified by the TFI together with the direction.
TBF = TFI + Direction
GPRS General Packet Radio ServicesAir interface aspects
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GPRS: Additional Logical Channels
PBCCH
Signallingand Control
PacketTraffic Channels
PCCCH
PPCH
PRACH MS initiates uplink transfer
PAGCH Resource assignment to an MS
PNCH Notifying PtM Packet Transfer
Broadcast of packet dataspecific information
PDTCH Packet Data Transfer; (multislot)
PACCH
DL
UL
DL
DL
DL
DL & ULPTCH
Signalling: resource allocation,acknowledgements, PC, TA, etc.
Paging MSs for packet dataand circuit switched services
PDCH: Packet Data Channel:
GPRS General Packet Radio ServicesAir interface aspects
FCCH No Direct EquivalentSCH No Direct EquivalentBCCH PBCCHPCH PPCHRACH PRACHAGCH PAGCHNCH PNCHSDCCH PCCCH/PACCHTCH PDTCHSACCH PACCHSACCH PTCCHFACCH PACCH
CCCH PCCCH
PDCH
GPRS General Packet Radio ServicesAir interface aspects
Network transmits Timing Advance ControlMessage with length of 4 Normal Burs ts
on PTCCH/Downlink
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GPRS Allocation of physical resource
Allocation of physicalresource
fixed
dynamic
Extended dynamic
Allocation of physical resources can be done belonging3 different modes. Fixed and dynamic allocation is mandatory, extended dynamic allocation is optional.
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downlink
USFRadio Block B(n)
USF = R1
USF = R2
USF = R3
USF =R4
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)
GPRS Dynamic AssignmentUSF = Uplink State Flag
USF sent in downlink Radio Blockpoints to the user of the next
uplink Radio Block (or the next 4 Radio Blocks, if USF Granularity bit is set)
GPRS General Packet Radio ServicesAir interface aspects
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downlink
USFRadio Block B(n)
USF = R1
USF = R2
USF = R3
USF =R4
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)
GPRS Extended Dynamic AllocationUSF = Uplink State Flag
USF allowing to transmit 1 or 4 Radio Blocks on that PDCH and on all higher
numbered assigned PDCH’s
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B0 - B11 = Radio Blocks T = Frame used for PTCCH X = Idle frame
Matrix with Nx12 elements: 12 lines, corresponding to the12 Radio Blocks within the 52 Multiframe.N columns, depending on theN assigned timeslots withthe Timeslot Allocation Vector
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Mobile Originated Packet TransferMobile Originated Packet Transfer
MS Net-work
Packet Channel Request1
2 Packet Immediate Assignment
Packet Resource Request3
4 Packet Resource Assignment
PAGCH or AGCH
PRACH or RACH
PACCH
PACCH
Phase One Access
Phase Two Access
(optional)
Packet Channel Request1
2 Packet Immediate Assignment
Packet Resource Request3
4 Packet Resource Assignment
PAGCH or AGCH
PRACH or RACH
PACCH
PACCH
Phase OneAccess
Phase Two Access(optional)
GPRS Packet Data Transfer
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GPRS Packet Data Transfer
Mobile originated data transfer: GPRS channel request
Channel request via RACH
Packet Channel requestvia PRACH
Single block establishment
One phase access request
One phase access request
or
Short access request
Two phase access request
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GPRS Packet Data Transfer
Network originated data transfer
Common Control Channels
Common Control Channels
Packet Common Control Channels
Packet switched paging
Circuit switched paging
Circuit switched paging
Packet switched paging
or
GPRS General Packet Radio ServicesAir interface aspects