Download GPRS in BSS overview

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
3G
EDGE
GPRS
2.5G
HSCSD
GSM
2G
GSM Evolution
2G
2.5G
GSM
GPRS
GSM
200 KHz carrier
8 full-rate time slots
16 half-rate time slots
GPRS
200 KHz carrier
115 Kbps peak data rates
HSCSD
HSCSD
Circuit-switched data
64 Kbps peak data rates
3G
EDGE
EDGE
200 KHz carrier
Data rates up to 384 Kbps
8-PSK modulation
Higher symbol rate
UMTS
UMTS
5 MHz carrier
2 Mbps peak data rates
New IMT-2000 2 GHz spectrum
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
GPRS packets can be transmitted in
16
the short free periods between busy
hour calls
14
12
2TRX = 14 Speech TS
2% blocking means
10
8 Erlang speech traffic

TCH
On average 6 TS free !
8
6
4
16
2
14
12
10
TC
H
0
8
6
1:00 PM
4
2
0
03:00
06:00
09:00
12:00
15:00
18:00
21:00
00:00
1:15 PM
1:30 PM
1:45 PM
GPRS Vs GSM
GPRS
1. SUPPORTS BOTH CKT.
SWITCHED as well as
packet switched service.
Vs
GSM
Only circuit switched.
2. MS Utilizes Automatic
retransmission (ARQ) at
data link layer to re-transmit
error frames.
No re-transmission is
provided.
3. Multiple time slots can be
allotted to a single user
Single time slot per user.
4. One time slot can be allotted
to several users.
Single time slot per user.
5. Charging/ billing more complex
(Volume based, Q.O.S. based)
Simple time-based billing.
TYPICAL GPRS SERVICES
* 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
Advertising -
A user nearing a cinema hall or
a restaurant receives flashes of
advertisement
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
GPRS Network Elements
•
•
•
•
•
•
•
•
•
Network Element Software
SGSN
SG1
GGSN
G1
Firewall
Checkpoint
Ethernet Switch
N/A
DNS
HP-UX 11.00
CG
HP-UX 10.20
Border Gateway
BGP4
DHCP
HP-UX 11.00
Hardware
DX Platform
IP650
IP650
Cisco Catalyst
HP 9000 A class
HP K class
IP650
HP 9000 A class
GPRS
ARCHITECTURE
GPRS Interface
MSC/
VLR
HLR
SMSGMSC
EIR
Signalling and data
Gr
Gs
Gd
Gf
Signalling
SGSN
BSC
GGSN
Gb
Air (Um)
Gn
Gn
GGSN
Gp
Gi
External
packet
network
Inter-PLMN
GPRS
Backbone
SGSN Role
• Authentication, Authorization
• GTP tunneling to GGSN
• Ciphering & compression
• Mobility Management
• Session Management
• Interaction with HLR, MSC/VLR
• Charging & statistics
• NMS interfaces
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 CCCH
TS
TS
TS
TS
TS
TS
TS
TRX 2
TS
TS
TS
TS
TS
TS
TS
TS
TS
TS
Additional
GPRS
Capacity
Dedicated
GPRS
GPRS
Capacity Capacity
Territory border moves based
on Circuit Switched traffic load
Circuit
Switched
Territory
Packet
Switched
Territory
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
GPRS
Attach / Detach
Idle
READY
Timer Expiry
STANDBY
Timer Expiry
MS location
not known.
Subscriber is not
reachable by the
GPRS NW.
Standby
MS location known to
SGSN level.
MS is capable of receiving
Point-to-Multipoint data
and being paged for
Point-to-Point data
Ready
Packet
TX/RX
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 RA
update procedure.
GPRS Mobility Management
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.
PDP CONTEXT
ACTIVATION
PDP Context Activation
Accessing the HLR
•
(1) MS sends "Activate PDP Context
Request" to SGSN
•Access Point Name
•PDP Type (IP)
•PDP Address (empty == dynamic)
•
(2) SGSN checks against HLR
•Access Point Name
•Dynamic / static IP address
HLR
2.
BSC
BTS
SS7
1.
APN=
"Intranet.Ltd.com"
SGSN
DNS
GPRS
Backbone
IP Network
Access
Point
Intranet
GGSN
Internet
•
Access Point Name = Reference to an external packet data network the
user wants to connect to
SECURITY IN GPRS
GPRS SYSTEM HAS INHERITED THE GSM PH-2 SECURITY FUNCTIONS
• 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
ADDITIONAL GPRS SECURITY FEATURES ARE
• 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))
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
Evolution to EDGE
SMS G/IW MSC
HLR
Gd
M
S
BTS
P
U
C
BSC
MSC/VLR
Gr
S
EDGE
TRU
ISP Network
Gs
Gb
M
AUC
SGSN
GGSN
Gn
Gn
Backbone
Network
Gi
Corporate
Network
EDGE increases capacity
voice
voice
voice
voice
voice
Standard GSM Transceiver
voice
voice
voice
EDGE Transceiver
voice
voice
Free
TS
Free
TS
Data
System upgrade for EDGE
EDGE TRU
B
R
S
B
C
S
BSC Software Upgrade
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!