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INTRODUCTION
What is GPRS• GPRS is a new set of GSM-bearer services
that provide packet mode transmission within the GSM network & interconnects with external packet data networks.
NEED FOR GPRS
• Existing Cellular networks have problems:• Data Rates too slow – about 9.6 kbps• Connections setup too long & complicated• Proves expensive for bursty traffic utilization• Inefficient resource utilization for bursty
traffic• No efficient method for packet transfers
GPRS (General Packet Radio Service ) :
• Reuse the existing GSM infrastructure• Introduce packet-switched routing functionality• Better data transfer rates• Low cost and connectivity-oriented• Migration Path to 4G Networks• “Always on” / always connected• After initial ‘log-on’, user is permanently connected to
end service• Network resources only used when information ready to
be exchanged
How Does GPRS Work?
When a user turns on a GPRS device, typically it will automatically scan for a local GPRS channel. If an appropriate channel is detected, the device will attempt to attach to the network. The SGSN receives the attach request, fetches subscriber profile information from the subscriber’s HLR node, and authenticates the user. Ciphering may be established at this point.
GPRS Architecture
• GPRS = GSM + packet switching. GPRS has the features of a real data network.
• Speeds up to 190 kbps (theoretical maximum)• No dial-up modems needed, but direct connections.• Billing based on sended/received bits, no telephone
ticks.• All applications available (www, e-mail, ftp,..)• The setup time is negligible – less than a second
GPRS Architecture Continue….
• How is the high speed of GPRS realized? Dynamic assignment of bursts to a user. In GSM 1
burst per user. In GPRS theoretical maximum of 8 bursts per user.
• 1 GSM-burst .In 1 burst 114 databits• So in 8 bursts 8*114=912 databits.• As We know that a GSM-frame takes 4,615 ms.
The maximum speed for gprs is then (912)/(4,615.10-3) = 197617 bits per second. Division by1024 because 1 kbit=1024 bits. So (197617)/(1024) = 192 kbit/s.
Applications of GPRS
• CHAT• TEXTUAL AND VISUAL INFORMATION • STILL IMAGES • MOVING IMAGES • DOCUMENT SHARING/ COLLABORATIVE
WORKING• AUDIO• JOB DISPATCH • CORPORATE EMAIL• INTERNET EMAIL• VEHICLE POSITIONING
Advantages of GPRS
• Always-On Connection• Faster Data Transfer Rates• Robust Connectivity• Broad Application Support• Security Support
PACKET TRANSFER -GGSN decapsulates and sends to PDNs.
-A laptop connects with a GPRS-capable handset.
-The handset communicates with GSM base station.
-Base station sends the GPRS packets to SGSN.
-SGSN encapsulates packets
-Handset location information is updated in other GSM components, such as HLR.
-SGSN sends encaps. packets to GGSN.
CONCLUSIONThe GPRS should cost uses less than circuit-switched
services since communication channels are being used on a shared basis and also the packets are need-based rather than dedicated only to one user.
The next stepping stone would be moving towards 4G by implementing EDGE (Enhanced Data rates for Global Evolution),
The GPRS is the key transition phase and is a fundamental requirement for Third Generation Mobile Communications.