gprs standards
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GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Standards Overview
By
Mohan Palat
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS in a GSM Network
BTS
BSC
MSC
PSTN
VoiceCalls
GSM
SGSN GGSN
PacketDataNetwork
GPRS
Packet DataCalls
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
Main Concepts
Packet-based transmission
1 to 8 timeslots can allocated on the air interface per carrier
Timeslots can be shared between active users
Interworking with external IP and X.25 networks
QoS - different QoS levels defined
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
Main Concepts - continued
No handovers in GPRS (on the RF interface) only cell reselection
Uplink and Downlink timeslots allocated independently
1 2 3 4
1 2
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
Point to Point Point to MultiPoint (PTM)
Types of Services
• Requires knowledge of the location of receivers
ServiceRequester
GPRS Network
ServiceRequester
GPRS Network
• Service Requester specifies Receiver, Geographic Area (for PTM calls)
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
PTM - Multicast PTM - Group Call
Types of MultiPoint (PTM) Service
Message may be targeted to specific group orto all subscribers within a geographic area(s)
NOTE: No subscription is required to receive a PTM-Multicast message
Defined GPRS Geographic Area(s)
ServiceRequester
Message transmitted to a specific receiver group - messages are transmitted only to cells containingreceiver group members
ServiceRequester
Cells
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
PTM - IP Multicast
GPRS Network
ServiceRequester
Types of PTM Services (cont.)
IP Network
• IP messages are sent between participants• Group can be internal to PLMN or distributed across internet• Messages are compliant with Internet Protocols
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Data Rates
Channel Coding Scheme Code Rate Data Rate
CS-1 1/2 9.05 Kbps
CS-2 2/3 13.4 Kbps
CS-3 3/4 15.6 Kbps
CS-4 1 21.4 Kbps
- Data Rates are per timeslot
- Maximum of 8 timeslots per carrier (shared among multiple users)
GPRS Data Rates
GPRS Sales Training 1999 - Greater China Network Solutions Division
Data Rate for Mobile Classes
Rate Timeslots
1 2 3 4 5 6 7 8
9.05 9.05 18.1 27.15 36.2 45.25 54.3 63.35 72.4
13.4 13.4 26.8 40.2 53.6 67 80.4 93.8 107.2
15.6 15.6 31.2 46.8 62.4 78 93.6 109.2 124.8
21.4 21.4 42.8 64.2 85.6 107 128.4 149.8 171.2
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
SGSN
Intra PLMNBackbone
GPRS Backbone Networks
SGSN
GGSN BG
Inter PLMNBackbone
SGSN
Intra PLMNBackbone
SGSN
BG GGSN
• Every intra-PLMN network is a private IP network• Inter-PLMN networks based on agreements between operators
PLMN PLMN
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
BTS
BSC
MSC
PSTN
GSM
GPRS Network Interfaces
SGSN GGSN
PacketDataNetwork
GPRSA
Abis
All the GPRS interfaces start with “G”
Current GSM interfaces
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Network Interfaces - Gb
SGSNGGSN
PacketDataNetwork
GPRS
BTS
BSC
MSC
PSTN
GSM
A
Abis
Gb• Used for both signalling and user data exchange• Based on Frame Relay link protocol• frame relay virtual circuits between BSS & SGSN• data (PDU) field: 1-600 octets in size
• Virtual circuits may be multi-hop• network of frame relay switching nodes
• Users multiplexed over the Gb link• Access rates can vary over the Gb link
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Network Interfaces - Gs
SGSNGGSN
PacketDataNetwork
GPRS
BTS
BSC
MSC
PSTN
GSM
A
Abis
Gs
• SS7 link between SGSN and MSC• Mainly for signalling (no data flow)
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Network Interfaces - Gr/Gc
SGSNGGSN
PacketDataNetwork
GPRS
BTS
BSC
MSC
PSTN
GSM
A
Abis
HLR
Gr
Gc
• SS7 link between SGSN/GGSN and HLR• Signalling link, no user data transfer• Primarily for
• lookup of GPRS subscriber info in HLR• GPRS mobile roaming (routing) information
•
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Network Interfaces - Gn
SGSN GGSN
PacketDataNetwork
GPRS
BTS
BSC
MSC
PSTN
GSM
A
Abis
Gn
• IP network protocol (UDP/IP, TCP/IP)• Used for signalling and data transfer• GPRS Tunnelling Protocol (GTP) operates over IP
• User data encapsulated with GTP• May be multi-hop
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Network Interfaces - Gi
SGSN GGSN
PacketDataNetwork
GPRS
BTS
BSC
MSC
PSTN
GSM
A
Abis
Gi
• IP or X.25 network protocol• Used for both signalling and data transfer• Main interconnection point between GPRS network and external packet data network
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Network Interfaces - Gp
SGSNGGSN
PacketDataNetwork
GPRS
BTS
BSC
MSC
PSTN
GSM
A
Abis
Gp
• IP network protocol • Can be an Inter-PLMN backbone (internet, leased line)• Provides Gn interface + security• Connects to an external GPRS network
GGSN
External PLMN
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Interfaces - Summary
GGSN
SGSN
Gb
MSC
Other Networks
Echo
XCDR
Voice
BSC
BTS BTSBTS
VLRA
Gs
Gi
Gn
Gp GPRS on adifferent PLMN
HLRGr
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
Packet Control Unit (PCU)
PCU
BTS BSC GSN
BTS BSC GSN
BTS BSC GSN
• Provides GPRS radio channel control functions
(1)
(2)
(3)
PCU
PCU
Circuit switched Packet switched
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
IMSI - same as GSM (Packet) TMSI -
local to an SGSN assigned both by MSC/VLR and SGSN MSC/VLR uses 00, 01, 10 & SGSN 11 as the two most
significant bits MS can be allocated 2 TMSIs simultaneously
PDP Address GPRS Mobile has one or more network layer addresses can be temporary or permanent (eg, IP address)
GPRS Mobile Identification
GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Subsystem Identities
GSN Address each SGSN and GGSN has an IP Address
GSN Number SGSN has a number for communication with HLR, etc.
TLLI (Temporary Logical Link Identity) identifies the logical link between MS and SGSN used for network layer routing
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
IMGI (International Group Mobile Identity) defines 2 levels of identification
Service provider
Application Level IMGI can be stored on SIM Card or on the ME 2 types of IMGIs: HPLMN IMGI or IMGIs that can be
used in multiple PLMNs IMSI used for authentication Subscriber Profile:
subscribed services (PTP, PTM-G etc) subscriber profile (priority, throughput, etc)
PTM Group Identification
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
Class A: supports both GPRS and Circuit-Switched (including SMS) user can make/receive calls on both services simultaneously mimimum of 1 timeslot available to each type of service
Class B: supports both GPRS and Circuit-Switched only one type of service at a time can be attached to both services
Class C: can be only attached to one service at a time can receive/make calls from default/manually selected
service
GPRS Mobile Classes
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
Type 1: Classes 1 through 12 Class 12: 4 consecutive ts receive, transmit on 3rd. ts OR 2
consecutive ts receive and transmit
Type 2: Classes 13 through 18 Can simultaneously transmit and receive on timeslots Classes 13 = 3 ts, Class 14 = 4 ts ….. Class 18 = 8 ts
Type 3: Half Duplex, power efficient mode Classes 19 through 28 Class 19-23 supports ts from 3-8 Classes 24-28 supports ts from 3-8
GPRS Mobile Types
Difference is thespacing of PACCH
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS must interwork with the following external data networks:
X.25 networks IP networks a. user’s IP address is allocated from a pool of unused IP
addresses upon activation of access to IP network
b. user’s IP address is permanently allocated
other GPRS PLMNs
GPRS Network Interworking
GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Support in Cells
A cell may or may not support GPRS
Non-GPRS Cells
GPRS Cells
GPRS Sales Training 1999 - Greater China Network Solutions Division
Tunnelling in GPRS
GPRS Tunnelling Protocol (GTP)
Point to Point path through one or more intermediate nodes
Data Packet add GPRS Tunnelling Protocol header
• contains endpoint identifiers insert this in a TCP or UDP packet data unit insert this in an IP packet data unit
SGSN GGSN
IP Backbone
PLMN 2PLMN 1
GPRS Sales Training 1999 - Greater China Network Solutions Division
“Anonymous Acess” concept
MS does not identify itself (IMSI) Authentication not required for Anonymous Access Temporary TLLI assigned to MS
Regular GPRS call: all GPRS activities can be traced to a GPRS subscriber
Anonymous GPRS call: all GPRS activities can be traced only to an auxiliary TLLI.
Mobile requests Anonymous Access, and a logical link to SGSN (TLLI) is established
Examples: Services where Service Provider pays for the call Services where user confidentiality is required
GPRS Sales Training 1999 - Greater China Network Solutions Division
Half Duplex Mode
Fixed vs Dynamic Allocation Dynamic: MS must continuously monitor downlink
(USF bits) Fixed: MS is given specific time to start and stop
transmitting
Fixed Allocation Mode is the Half Duplex Mode of operation
GPRS Sales Training 1999 - Greater China Network Solutions Division GPRS Sales Training 1999 - Greater China Network Solutions Division
GPRS Standards
GPRS Standards being done in phases
PHASE 1:
• PTP (TCP/IP, connectionless)• X.25 Support • Network Interfaces (Gn, Gb, Gr, Gp, Gs, Gi)• Security• Charging Issues (information to be collected)• SMS over GPRS• anonymous access
PHASE 1:
• PTP (TCP/IP, connectionless)• X.25 Support • Network Interfaces (Gn, Gb, Gr, Gp, Gs, Gi)• Security• Charging Issues (information to be collected)• SMS over GPRS• anonymous access
PHASE 2:
• PTM-Multicast• PTM-Group Call• Supplementary Services• Additional External Network Interfaces
GPRS Sales Training 1999 - Greater China Network Solutions Division
STAGE 1STAGE 1
STAGE 2STAGE 2
STAGE 3STAGE 3
02.60General GPRS Overview
03.60 03.64 03.61 03.62 General System Radio Arch. Point to MultiPoint Point to MultiPointDesc. & Network Description Multicast Group CallArchitecture
02.60 04.65 09.60 04.61 04.62 LLC SNDCP Gb Interface PTM-M Services PTM-G Services
08.64 07.60 09.60 04.60 BSSGP User External NetworkGb Interface Interworking Interworking
• Plus modifications to existing standards (Stage 3)
GPRS Standards Breakdown
Read 03.60 if you have time to read only one document !
GPRS Sales Training 1999 - Greater China Network Solutions Division
Air Interface - New Channels
PDTCH - Packet Data Traffic Channel PACCH - Packet Associated Control Channel
PBCCH - Packet Broadcast Control Channel
PCCCH PAGCH - Packet Access Grant Channel PPCH - Packet Paging Channel PNCH - Packet Notification Channel
PRACH - Packet Random Access Channel
Downlink Only
Uplink Only
Downlink Only
Uplink &Downlink
GPRS Sales Training 1999 - Greater China Network Solutions Division
Air Interface Timeslot Allocation
Upto 8 timeslots can be allocated for GPRS maximum one GPRS carrier per cell (initial release)
Air interface timeslot configuration: GPRS only timeslots GPRS and Circuit Switched timeslots Circuit Switched (GSM voice) timeslots
BCCHCarrier
0 .
.
7
Second Carrier
BCCHCarrier
0 .
.
7
Second Carrier
BCCHCarrier
0 .
.
7
Second Carrier
Switchable
TCH
BCCH/CCCHwith GPRS msg
GPRS only
GPRS Sales Training 1999 - Greater China Network Solutions Division
Mobile States and Transitions
IDLE
READY
STANDBY
GPRS Attach GPRS Detach
Packet DataTransmission
READY timer expiryorForce to STANDBY
STANDBYtimerexpiry
IDLE:
- not attached to GPRS
- MS, SGSN has no valid location routing information
- MS can only receive PTM-M STANDBY
- MS attached to GPRS network
- MS can receive pages for incoming data
- MS can receive CS pages READY
- MS sends and receives packet data
- MS remains in this state until it times out
GPRS Sales Training 1999 - Greater China Network Solutions Division
Basic Call Processing
MS turns on. MS initiates LOGON procedure with SGSN
GGSN gets location update of MS.
HLR assigns IP address to MS from its static pool of IP addresses
MS goes into standby mode
GPRS Sales Training 1999 - Greater China Network Solutions Division
Mobile Originated Call
Channel Request on PRACH or RACH
BSS assigns initial resources to MS (Timing Advance, Timeslots)
Data Blocks
Packet Acknowledge
Packet Data Channel
PACCH Channel
MS goes into STANDBY Mode
GPRS Sales Training 1999 - Greater China Network Solutions Division
Mobile Terminated Call
Paging Request from BSS
BSS assigns initial resources to MS (Timing Advance, Timeslots)
Data Blocks
Packet Acknowledge
Packet Data Channel
PACCH Channel
MS goes into STANDBY Mode
Channel Request on PRACH or RACH