1. 2.5 G Cellular Systems and Architecture

2. Introduction to GPRS and EDGE 2.5G System Architecture
2.5G Cellular System
Introduction to GPRS and EDGE
2.5G System Architecture

3. Evolution of Wireless

4. GPRS General Packet Radio Service
Value added service to 2G to connect users to IP (Internet Protocol) -based data networks
Forms basis of Packet Switched Network
Data rate up to 115 Kbps with GPRS and 384 Kbps with EDGE

5. Motivation for GPRS
Wireless access to internet and intranet

6. Circuit and Packet Switching
Circuit Switching
Dedicated resources to each user
Higher performance and higher cost
Packet Switching
Shares resources with multiple users
Lower performance and lower cost
Requires MAC (Medium Access Control)
Requires memory buffering

7. Circuit Switching Network

8. Packet Switching Network

9. EDGE Enhanced Data rate for Global Evolution
Also called as Enhanced GPRS or EGPRS
Improves efficiency of GPRS by use of advanced modulation technique- Octal PSK or 8 PSK Modulation

10. GPRS Network

11. GPRS Network Terms

12. Major functions of SGSN
Provides Packet Switching and routing for GPRS services- analogous to MSC in 2G
Contains a database of subscribers, including visitors (roamers) and home subscribers- analogous to VLR in 2G
Handles authentication and admission control – analogous to MSC/HLR/AuC

13. Major functions of GGSN
Provides Packet Switching and Routing for GPRS services
Provides interface to external Public Data Networks (PDNs) e.g. the Internet
First point of contact for packet session originating outside the PLMN

14. Major functions of GERAN
Handles admission control
Handles radio resource management
Performs packet relay and routing functions

15. Elements of Communication System

16. Typical Wireless Terminal

17. Typical 2.5G Wireless Terminal