Date post: | 16-Dec-2015 |
Category: |
Documents |
Upload: | miles-owens |
View: | 326 times |
Download: | 24 times |
GPRS/EDGE
OVERVIEW
Course contents• GPRS Background and Evolution
• GSM/GPRS network
• GPRS Architecture
• IP Addressing in GPRS
• GPRS Air Interfaces
• MS types and Coding Schemes
• Mobility Management
• PDP Context Activation Sequence
• GPRS Roaming
• GPRS Charging
• Practical Demonstration of GPRS
GPRS
BACKGROUND AND
EVOLUTION
GPRS BACK GROUND• With Mobile penetration reaching its full potential, GPRS gives Mobile operators competitive edge and optimum use of the infrastructure.
•SMS is a good example of just how hungry users are for data services.
• The main Objective of GPRS is to offer the access to standard data networks, using protocols e.g. TCP/IP and X.25
• Transactions such as Credit Card checks and a variety of telemetric applications benefit from the fast session set-ups.
• GPRS enables efficient use of radio resources by allowing many data users to share the same interface on a statistical basis.•The main benefits of GPRS are that it reserves radio resources only when there is data to be sent
• Mobile users doesn’t have to connect to the network each time he wants to transfer the data, he can stay connected all day.
Evolution from GSM to 3G
The GSM Growth Phases
GSM2G
HSCSD
GPRS2.5G
EDGE
3G
GSM Evolution
GPRS200 KHz carrier115 Kbps peak data rates
EDGE200 KHz carrierData rates up to 384 Kbps8-PSK modulationHigher symbol rate
UMTS5 MHz carrier2 Mbps peak data ratesNew IMT-2000 2 GHz spectrum
GSM200 KHz carrier8 full-rate time slots16 half-rate time slots
GSM GPRS EDGE UMTS
3G2.5G2G
HSCSD
HSCSDCircuit-switched data64 Kbps peak data rates
MAIN ADVANTAGES FOR OPERATORS
• More Revenue :
By providing more than a mobile connection.
Also operator can charge on the basis of type and amount of content accessed.
• Huge Potential Market for Data Sevices :
Mobile Phone and Internet, both are fastest growing technologies and GPRS is the merger of two.
• Fast Roll-out and Continuous Network Expansion :
GPRS is an integral part of GSM.
• GPRS uses excess voice capacity for data :
GPRS Packets are transmitted in short, free periods between busy hour calls.
Free GSM Capacity
0
2
4
6
8
10
12
14
16
1:00 PM 1:15 PM 1:30 PM 1:45 PM
TCH
0
2
4
6
8
10
12
14
16
03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00
TC
H
GPRS packets can be transmitted in
the short free periods between busy
hour calls
2TRX = 14 Speech TS
2% blocking means
8 Erlang speech traffic
On average 6 TS free !
GPRS Vs GSM1. SUPPORTS BOTH CKT. Only circuit switched. SWITCHED as well as packet switched service.
2. MS Utilizes Automatic No re-transmission is retransmission (ARQ) at provided. data link layer to re-transmit error frames.
3. Multiple time slots can be Single time slot per user. allotted to a single user
4. One time slot can be allotted Single time slot per user. to several users.
5. Charging/ billing more complex Simple time-based billing. (Volume based, Q.O.S. based)
GPRS Vs GSM
* Communications- E-mail, fax, intranet/ internet access.
* Value added services - Information services, games, e-commerce.
* Location-based applications - Navigation, traffic conditions, airline/rail schedule, location finder.
* Vertical applications - Freight delivery, fleet management, sales-force automation
* Location sensitive A user nearing a cinema hall or Advertising - a restaurant receives flashes of advertisement
TYPICAL GPRS SERVICES
GPRS
NETWORK ELEMENTS
GSM NETWORK ELEMENTS
The Main elements of GSM are:
• NSS :•MSC•VLR•HLR (Includes Authentication Center and Equipment Identity Register)
• BSS :•BSC•BTS•Transcoder
• NMS•Fault Management•Configuration Management•Performance Management
• Network Element Software Hardware• SGSN SG1 DX Platform • GGSN G1 IP650• Firewall Checkpoint IP650• Ethernet Switch N/A Cisco Catalyst • DNS HP-UX 11.00 HP 9000 A class• CG HP-UX 10.20 HP K class• Border Gateway BGP4 IP650• DHCP HP-UX 11.00 HP 9000 A class
GPRS Network Elements
GPRS
ARCHITECTURE
GPRS Interface
HLR
Air (Um)
Gb
Gs Gr Gf
Gn
Gn Inter-PLMN
GPRS Backbone
Gp
External packet network
Gi
SGSN
EIR
BSC
MSC/ VLR
SMS- GMSC
Gd
GGSN
GGSN
Signalling and data
Signalling
• Authentication, Authorization
• GTP tunneling to GGSN
• Ciphering & compression
• Mobility Management
• Session Management
• Interaction with HLR, MSC/VLR
• Charging & statistics
• NMS interfaces
SGSN Role
GGSN Role
• Interface to external data networks• Encapsulate in GTP and forwards end user
data to right SGSN• Routes mobile originated packets to right
destination• Filters end user traffic• Collects charging and statistic information
for data network usage
GPRS
AIR INTERFACES
Different GPRS Capacity Types
TRX 1
TRX 2
CCCH TS TS TS TS TS TS TS
TS TS TS TS TS TS TSTS
CircuitSwitchedTerritory
PacketSwitchedTerritory
Territory border moves basedon Circuit Switched traffic load
GPRSCapacity
DedicatedGPRS
Capacity
TS TS
AdditionalGPRS
Capacity
TS TS
GPRS
MS CLASS &
CODING SCEMES
MS Class• CLASS A:
Supports simultaneous attach, simultaneous activation, simultaneous monitor, simultaneous invocation, and simultaneous traffic.
• CLASS B: Simultaneous traffic shall is not supported. The mobile user can make and/or receive calls on either of the two services sequentially but not simultaneously. The selection of the appropriate service is performed automatically
• CLASS C: Supports only non-simultaneous attach. Alternate use only.
• The status of the service which has not been selected is detached, that is, not reachable.
GPRS Channel Coding Schemes
GPRS
MOBILITY MANAGEMENT
Mobility Management State
Idle
Standby
Ready
PacketTX/RXSTANDBY
Timer Expiry
GPRSAttach / Detach
READYTimer Expiry
MS location known to SGSN level.
MS is capable of receiving Point-to-Multipoint data and being paged for Point-to-Point data
MS location not known.
Subscriber is notreachable by the GPRS NW.
MS location known to cell level.
MS is transmitting or has just been transmitting. MS is capable of receiving Point-to-Point data and Point-to-Multipoint data.
Routing Area
RAI = MCC+MNC+LAC+RAC
GPRS Mobility Management
Routing Area :
The RA is a new concept for tracing the MS location.
Cell =< RA =< LA served by one SGSN
RAI = MCC + MNC + LAC + RAC
Every time the MS sees the new RAI is has to initiate the RAupdate procedure.
Mobility Management States :
•The IDLE State is when the MS is not connected.
•The Standby State is when the MS is connected to the GPRS Network
•The Ready State is when the MS is ready to connect to the external IP Network.
Changing between states can be initiated from the MS, from the network and from the timers set.
GPRS Mobility Management
PDP CONTEXT
ACTIVATION
BTS BSC
SGSN
GGSN
Intranet
GPRS Backbone IP Network
SS7
HLR
DNS
• (1) MS sends "Activate PDP Context Request" to SGSN
•Access Point Name•PDP Type (IP)•PDP Address (empty == dynamic)
• Access Point Name = Reference to an external packet data network the user wants to connect to
Internet
APN="Intranet.Ltd.com"
1.
2.
AccessPoint
• (2) SGSN checks against HLR•Access Point Name•Dynamic / static IP address
PDP Context ActivationAccessing the HLR
SECURITY IN GPRS
• Authentication of the subscriber
• IMEI Checking
• User Identity Confidentiality (TMSI in GSM, P-TMSI in GPRS)
• Ciphering of the data traffic between MS and SGSN
• Private IP Addressing in the GPRS backbone.
• Ciphered links and authentication between nodes in the GPRS Backbone.
• Screening of packets coming from the external networks (Firewall).
(P-TMSI is used to derive the Temp Logical Link Identity (TLLI))
GPRS SYSTEM HAS INHERITED THE GSM PH-2 SECURITY FUNCTIONS
ADDITIONAL GPRS SECURITY FEATURES ARE
The Abbreviation
GPRS = General Packet Radio System
EGPRS = GPRS + EDGE modulation
EDGE – Provide 3G services today
• Provide 3G services with existing licenses
• New modulation optimized for wireless data services
• Link adaptation: Take highest possible rate
• Covered by existing GSM licenses
• Same channel structure, network infrastructure, frequency
planning and protocol as today’s GSM
M
SBTS
PUC
BSC MSC/VLR
HLR
SGSN GGSN
Backbone Network
ISP Network
CorporateNetwork
AUC
SMS G/IW MSC
Gb
Gd
Gs
Gn
Gr
Gn
GiEDGE TRU
M
S
Evolution to EDGE
voice voice voice voice voice
voice voicevoicevoice voice Free TS
DataFree TS
Standard GSM Transceiver
EDGE Transceiver
EDGE increases capacity
System upgrade for EDGE
B
S
C
BSC Software Upgrade
R
B
S
EDGE TRU
EDGE enabled RBS
What EDGE would mean to subscribers
• Streaming Applications
• Very high speed downloads
• Corporate Intranet connections
• Quicker MMS
• Video Phone
• Vertical corporate applications – Video
Conference, Remote presentations
Thank You!