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 is a step towards 3G & is often referred to as 2.5G


👉Benefits of GPRS

  • New Data Services
  • High Speed (Data Rate 14.4 – 115 kbps)
  • Efficient use of radio bandwidth  
  • Circuit switching & Packet Switching can be used in parallel
  • Constant connectivity

👉Salient Features of GPRS

  • Important step on the path to 3G
  • GPRS is an overlay network over the GSM
  • Provides Data Packet delivery service 
  • Billing based on volume of data transferred 

👉GPRS Terminals or Classes 

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 be active in either GPRS or GSM mode, but not at the same time


👉GPRS Network Elements

GPRS Architecture is same as GSM except few hardware modifications :
  • GPRS includes GSNs
  1. SGSN  : Serving GPRS Support Node
  2. GGSN : Gateway GPRS Support Node
  • GPRS Register

👉GPRS Architecture





👉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

👉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 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  

👉Applications of GPRS

  • Web browsing
  • Corporate & Internet Email 
  • Vehicle Positioning
  • Remote LAN Access
  • Home Automation
  • Document Sharing/Collaborative working

👉Comparison of GSM & GPRS





👉Enhanced Data Rate for GSM Evolution (EDGE)

  • EDGE is a technology that gives GSM Networks the capacity to handle services for 3G. 
  • EDGE was developed to enable the transmission of large amounts of data at peak rates of up to 472kbps.
  • Users can experience average speeds of 80 kbps to 130 kbps. 
  • EDGE devices are backwards compatible with GPRS and will be able to operate on GPRS networks where EDGE has not yet been deployed.

👉EDGE

  • In 1st G AMPS(Advanced Mobile system ) developed in U.S in 1983
  • In 2ndG there was introduction of CDMA,TDMA and GSM
  • Between 2nd and 2.5thG of GPRS 
  • Between 2.5th and 3thG there was an introduction EDGE technology
  • EDGE- Enhanced Data  rate for GSM Evolution
  • Developed to increase the BW of GPRS technology
  • EDGE increases the BW from 144 Kbps to 384 Kbps


GSM


  • Global System for Mobile (GSM)
  • GSM is a 2G cellular standard developed to provide voice & data services using digital modulation.
  • Commonly used frequency bands are 900MHz & 1800 MHz
  • Uplink 890-915 MHz
  • Downlink 935-960 MHz

👉GSM Services

  • Tele-services: provide mobile telephony & emergency calling
  • Bearer services or data services: includes SMS, voice mailbox
  • Supplementary services: Call waiting, call hold, call barring, call forwarding, multi party call conferencing

👉GSM Network Architecture


GSM architecture is mainly divided into three 
Subsystems

  1. Base Station Subsystem (BSS)
  2. Network & Switching Subsystem (NSS)
  3. Operations & Support Subsystem (OSS)

  • Mobile Station (MS)

  1.           Mobile Equipment (ME)
  2.           Subscriber Identity Module (SIM)

  • Base Station Subsystem

  1.            Base Transceiver Station (BTS)
  2.            Base Station Controller (BSC)
  3. Network Switching Subsystem (NSS)
           MSC
           HLR
           VLR
           AUC
           EIR

👉Mobile Station

  • ME is a portable handheld device uniquely identified by IMEI
  • SIM contains the IMSI, It allows the users to send & receive calls

👉Base Station Subsystem

  • BSS handles  traffic and signalling between a mobile phone and the network switching subsystem.
  • BTS, contains the equipment for transmitting and receiving radio signals (TRX unit). It encodes, encrypts, multiplexes, modulates & feeds the RF signal to antenna. It communicates with MS and BSC

👉Base Station Controller

  • Typically a BSC has tens or even hundreds of BTSs under its control.
  • The BSC handles allocation of radio channels, receives measurements from the mobile phones, and controls handovers from BTS to BTS 

👉Network Switching Subsystem (NSS

  • NSS carries out telephone exchange and mobility management functions (where the subscribers are, allowing calls)
  • MSC is  responsible for routing voice calls and SMS as well as other services (such as conference calls, FAX, and circuit-switched data). The MSC sets up and releases the end-to-end connection, handles mobility and hand-over requirements during the call and takes care of charging
  • HLR: Stores information about each subscriber that belongs to its MSC. As soon as the mobile subscriber leaves its current local area, the information in HLR is updated.
  • VLR: Temporary database which updates whenever new MS enters its area, by HLR database. It assigns a TMSI to each MS entering the VLR area which keep on changing. It also controls those mobiles roaming in its area
  • Authentication center (AuC): Contains the algorithims for authentication as well as the keys for encryption. It also protects network operator from fraud
  • Equipment identity register (EIR): Stores all devices identification registered for this network. It handles real-time requests to check the IMEI of mobile devices that come from the switching equipment (MSC)

👉Operation & Maintenance Centre

They support management functions such as network inventory, network configuration and fault management, Storage of system software & data


Comparison b/w GSM & CDMA system