This document provides an overview of GPRS architecture and 3G cellular systems. It defines GPRS as a new bearer service for GSM that improves wireless access to packet data networks. Key benefits of GPRS include new data services, higher speeds up to 115 kbps, efficient use of bandwidth through statistical multiplexing, and constant connectivity. The document then describes statistical multiplexing and the network elements of GPRS such as SGSN, GGSN, and the GPRS register. It concludes with an overview of 3G technologies like UMTS and CDMA2000, their network architectures and frequency spectrums.

1. BY – NAVJOT KAUR
LECTURE-10
GPRS Architecture & 3 G CELLULAR
SYSTEMS

2. What is GPRS ?
 General Packet Radio Service (GPRS) is a new
bearer service for GSM that greatly improves and
simplifies wireless access to packet data networks
 GPRS applies packet radio principal to transfer user
data packets in an efficient way b/w MS & external
packet data network.

3. Benefits of GPRS
 New Data Services
 High Speed (Data Rate 14.4 – 115 kbps)
 Efficient use of radio bandwidth (Statistical
Multiplexing)
 Circuit switching & Packet Switching can be used in
parallel
 Constant connectivity

4. Statistical Multiplexing

5. Statistical Multiplexing …
 Statistical multiplexing is facilitated through packet
mode or packet oriented communication, which
amongst others is utilized in packet switched
computer networks. Each stream is divided into
packets that normally are delivered asynchronously in
a first-come first-serve fashion. Alternatively, the
packets may be delivered according to some
scheduling discipline for fair queuing or differentiated
and/or guaranteed quality of service.
 Statistical multiplexing of an analog channel, for
example a wireless channel, is also facilitated through
the following schemes:

6. Statistical Multiplexing …
 Random frequency-hopping orthogonal frequency
division multiple access (RFH-OFDMA)
 Code-division multiple access (CDMA), where
different amount of spreading codes or spreading
factors can be assigned to different users.
 Statistical multiplexing normally implies "on-demand"
service rather than one that pre-allocates resources
for each data stream. Statistical multiplexing schemes
do not control user data transmissions.

7. Salient Features of GPRS
 Important step on the path to 3G
 Standardized by ETSI (European Telecommunications
Standards Institute)
 GPRS is an overlay network over the GSM
 Provides Data Packet delivery service
 Support for leading internet communication protocols
 Billing based on volume of data transferred
 Utilizes existing GSM authentication and privacy
procedures.

8. GPRS Terminals
 Class A
 MS supports simultaneous operation of GPRS and
GSM services
 Class B
 MS able to register with the n/w for both GPRS &
GSM services simultaneously. It can only use one
of the two services at a given time.
 Class C
- MS can attach for either GPRS or GSM services

9. GPRS Network Elements
GPRS Architecture is same as GSM except
few hardware modifications :
 GPRS includes GSNs
 SGSN : Serving GPRS Support
Node
 GGSN : Gateway GPRS Support
Node
 GPRS Register

10. GPRS System Architecture
Other
GPRS
PLMN
PDN

11. Interfaces
 Gb – Connects BSC with SGSN
 Gn – SGSN – SGSN/GGSN (in the same network)
 Gp – SGSN –GGSN (in different networks)
 Gf – For equipment querying at registering time
 Gi – Connects PLMN with external Packet Data
Networks (PDNs)
 Gr – To exchange User profile between HLR & SGSN
 Gs – To exchange Database between SGSN & MSC
 Gd – Interface between SMS & GPRS

12. SGSN – Serving GPRS Support
Node
• Delivers data packets to mobile stations & vice-
versa
• Detect and Register new GPRS MS in its serving
area
• Packet Routing, Transfer & Mobility Management
• Authentication, Maintaining user profiles
• Its location register stores location info. & user
profiles

13. GGSN – Gateway GPRS Support
Node
• Interfaces GPRS backbone network & external
packet data networks
• Converts the GPRS packets from SGSN to the PDP
format
• Converts PDP addresses change to GSM
addresses of the destination user
• Stores the current SGSN address and profile of the
user in its location register
• Performs authentication
• Many-to- many relations among SGSNs & GGSNs

14. GPRS Register
 GPRS Register is integrated with GSM-HLR.
 Maintains the GPRS subscriber data and Routing
information.
 Stores current SGSN address

15. GPRS Backbone Network
 GSNs are connected through IP based backbone
 Two Backbones:
 Intra PLMN backbone networks that connects
GSNs of the same PLMN & are private IP networks
 Inter PLMN backbone networks that connects
GSNs of the different PLMN. Roaming agreement is
necessary
 GPRS Tunneling protocol (GTP)
 PLMN- Inter PLMN interconnect are called Border
gateways (performs security functions to protect Intra-
PLMN backbone against unauthorized users and
attacks).

16. Attachment & Detachment
Procedure
 GPRS attach
- User is registered in SGSN, after authentication
check from HLR
- SGSN assigns P-TMSI to MS
•GPRS detach
- Disconnection of MS from GPRS network is called
GPRS detach
- It can be initiated by MS or by network(SGSN or
HLR)

17. Third Generation Vision
 Common spectrum worldwide
– 1920-1980 MHz and 2110-2170 MHz
 Wide range of new services
– Data centric (e..g.. Internet) and multimedia oriented
– Data bit rates up to 2 Mb/s
 Seamless global roaming
 Improved security and performance
 Support a variety of terminal (from PDA to desktop)
 Intensive use of Intelligent Network (IN) technology

18. Why 3G?
 Higher bandwidth enables a range of new
applications!!
 For the consumer
 Video streaming, TV broadcast
 Video calls, video clips – news, music, sports
 Enhanced gaming, chat, location services…
 For business
 High speed teleworking / VPN access
 Sales force automation
 Video conferencing
 Real-time financial information

19. Upgrade paths for 2G
Technologies
IS-95 IS-136 & PDC
GSM-
EDGE
GPRS
HSCSD
IS-95B
Cdma2000-1xRTT
Cdma2000-1xEV,DV,DO
Cdma2000-3xRTT
W-CDMA
EDGE
TD-SCDMA
2G
3G
2.5G
3GPP
3GPP2

20. UMTS
 UMTS is the European vision of 3G.
 UMTS is an upgrade from GSM via GPRS or EDGE.
 The standardization work for UMTS is carried out by Third
Generation Partnership Project (3GPP).
 Data rates of UMTS are:
 144 kbps for rural
 384 kbps for urban outdoor
 2048 kbps for indoor and low range outdoor
 Virtual Home Environment (VHE)

21. UMTS Network Architecture
SD
Mobile Station
MSC/
VLR
Base Station
Subsystem
GMSC
Network Subsystem
AUC
EIR HLR
Other Networks
Note: Interfaces have been omitted for clarity purposes.
GGSN
SGSN
BTS
BSC
Node
B
RNC
RNS
UTRAN
SIM
ME
USIM
ME
+
PSTN
PLMN
Internet

22. UMTS Network Architecture
 UMTS network architecture consists of three
domains:
 Core Network (CN) : To provide switching, routing and
transit for user traffic.
 UMTS Terrestrial Radio Access Network (UTRAN) :
Provides the air interface access method for User
Equipment.
 User Equipment (UE) : Terminals work as air interface
counterpart for Node B. The various identities are:
IMSI, TMSI, P-TMSI, TLLI, MSISDN, IMEI, IMEISV.

23. UMTS Frequency Spectrum
• UMTS Band : 1900-2025 MHz and 2110-2200
MHz for 3G transmission.
• Terrestrial UMTS (UTRAN) : 1900-1980 MHz,
2010-2025 MHz, and 2110-2170 MHz bands

24. CDMA2000 evolution to 3G
IS-95B
IS-95B
Uses multiple code channels
Data rates up to 64kbps
Many operators gone direct to
1xRTT
1xRTT
CDMA2000 1xRTT: single carrier RTT
First phase in CDMA2000 evolution
Easy co-existence with IS-95A air
interface
Release 0 - max 144 kbps
Release A – max 384 kbps
Same core network as IS-95
1xEV-DO
CDMA2000 1xEV-DO: Evolved Data Optimised
Third phase in CDMA2000 evolution
Standardised version of Qualcomm High Data Rate
(HDR)
Adds TDMA components beneath code components
Good for highly asymmetric high speed data apps
Speeds to 2Mbps +, classed as a “3G” system
Use new or existing spectrum
1xEV-DV
CDMA2000
3xRTT
CDMA2000 1x Evolved DV
Fourth phase in CDMA2000 evolution
Still under development
Speeds to 5Mbps+ (more than
3xRTT!)
Possible end game.
CDMA
IS-95A
IS-95A
14.4 kbps
Core
network re-
used in
CDMA2000

25. CDMA 2000 1X
• Supports theoretical data rates of up to 307 kbps, with generally
experienced rates of 144 kbps.
• The newly introduced Q-PCH of CDMA 2000 enables the mobile
to be informed about when it needs to monitor F-CCCH and the
Paging Channel, thus improving on the battery life
• Introduction of Radio Configurations – Transmission formats
characterized by physical layer parameters such as data rates,
modulation characteristics, and spreading rate. RCs help in
providing for additional data rates.
• Quality and Erasure indicator bits (QIB and EIB) on the reverse
power control sub channel. These help in indicating to the BS
about bad frames or lost frames received at the mobile station, so
that they can be retransmitted
• Code channels are transmitted at full data rates during a data
burst
• Convolutional and Turbo coding techniques used
• Modulation technique used is QPSK

26. CDMA 2000 3X
• Offering data speeds up to 2 Mbps
• Using three standard 1.25 MHz channels within
a 5 MHz band
• Leveraging deployment experiences, and
manufacturers’ learning curves of today’s widely
adopted, commercially available CDMA systems
• Using Convolutional and Turbo coding
techniques
• Using QPSK as the Modulation technique