Gprs

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Computer Network:
GPRS

Besar Dika 105088
Dashmir Istrefi 104827
Blerim Emruli 105571

CONTENT

ABSTRACT 2
INTRODUCTION 3
CHAPTER ONE (Overview) 5
First Generation System 5
Second Generation System 6
Third Generation System 7
CHAPTER TWO (GPRS Usage) 9
Ways To use GPRS 9
CHAPTER THREE (GPRS Network Protocols) 13
CHAPTER FOUR (Requirements, Functionality) 16
LIMITED RADIO RESOURCES 18
SPEEDS LOWER IN REALITY 18
NO SUPPORT OF MOBILE TERMINATED CALLS 18
SUBOPTIMAL MODULATION 18
TRANSIT DELAYS 18
NO STORE AND FORWARD 18
REQUIREMENTS USING GPRS 19
PACKET SWITCHING 20
SPECTRUM EFFICIENCY 20
INTERNET AWARE 20
SUPPORTS TDMA AND GSM 22
INDUSTRY PARTICIPATION 22
CHAPTER FIVE (SECURITY ISSUES) 25
EXPECTATIONS 25
Security & Vulnerabilities 26
Spam 29
Phishing 30
Viruses 30
Solving/Mitigating the Problem 31
Separation of Voice and Data 31
Rate Limitation 31
Significance 32
CHAPTER SIX (FEELING GPRS) 33
GPRS IN MACEDONIA 34
CONCLUSION 36
APPENDIXES 37
GLOSSARY 38

ABSTRACT

GPRS (general packet radio service) is a new nonvoice service that is being added to existing IS-136 TDMA (time division multiple access) networks. How does it bring Internet to the mobile phone? This could be one good question if the reader of this project has no idea how GPRS works. Well a short answer just for introduction is that it provides transmission of IP packets over cellular networks. So, Web browsing, chat and e-mail, all offered by Internet will be available from GSM and TDMA service providers via GPRS. It is an upgrade of existing cellular network, without requiring the dedication of new channels, but actually it grabs a short time slots allocated from channels dedicated to voice traffic. In other words channels used for voice can be used for sending IP packets. So basically this is the idea used for bringing internet to your mobile phones. It is a 2.5G technology. We will explain about the generations of mobile technology later but very shortly because that is not our topic. INTRODUCTION

Figure 1.
Channel Division
And how they are used

So how actually it manages with the channels?
Channels are divided into slots, exactly in 8 slots. The maximum data transmission of each one of them is 13.4Kbps[1]. One of this slots is reserved for control. So it means that other seven can be used for GPRS traffic but in normal allocation 2 slots are reserved for voice traffic. Then we have 8-1-2=5 slots available. One of this slots is used for upload, because the user spends most of the time downloading rather than uploading data. It receives more than it transmits. So the remaining 5 slots are used in 4+1 proportion. 4 for download and 1 for upload. If this is so, and according to the fact that each slot has a maximum of 13.4Kbps transmission then a GPRS maximum data rate expected from service operator is 4x13.4=53.6Kbps so this is pretty much compared with a 56K modem dial-up connection. So users that are used to dial-up speeds will be pleased using their cell phone as modem while traveling. Others that are used with high speed internet, GPRS won’t fulfill their expectations. They’d better try 3G or sooner wait for 4G tech.

|Type |Upload (Sending) |Download (Receiving) | |GPRS |14 Kbps |28-54 Kbps | |GSM CSD |9.6-14 Kbps |9.6-14 Kbps | |HSCSD |28 Kbps |28 Kbps | |Dial-UP |56 Kbps |56 Kbps | |ISDN Standard |64 Kbps |64 Kbps | |ADSL |256 Kbps |512 Kbps | |Broadband |2 Mbps |2 Mbps |

Figure.
A comparison table[2]...
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