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Presentation on theme: "GPRS/EDGE OVERVIEW."— Presentation transcript:


2 Course contents GPRS Background and Evolution GSM/GPRS network
GPRS Architecture IP Addressing in GPRS GPRS Air Interfaces MS types and Coding Schemes Mobility Management PDP Context Activation Sequence GPRS Roaming GPRS Charging Practical Demonstration of GPRS


4 GPRS BACK GROUND With Mobile penetration reaching its full potential, GPRS gives Mobile operators competitive edge and optimum use of the infrastructure. SMS is a good example of just how hungry users are for data services. The main Objective of GPRS is to offer the access to standard data networks, using protocols e.g. TCP/IP and X.25 Transactions such as Credit Card checks and a variety of telemetric applications benefit from the fast session set-ups. GPRS enables efficient use of radio resources by allowing many data users to share the same interface on a statistical basis. The main benefits of GPRS are that it reserves radio resources only when there is data to be sent Mobile users doesn’t have to connect to the network each time he wants to transfer the data, he can stay connected all day.

5 Evolution from GSM to 3G The GSM Growth Phases 3G EDGE GPRS 2.5G HSCSD

6 GSM Evolution 2G 2.5G 3G GSM GPRS EDGE UMTS UMTS 5 MHz carrier
2 Mbps peak data rates New IMT GHz spectrum GSM 200 KHz carrier 8 full-rate time slots 16 half-rate time slots GPRS 200 KHz carrier 115 Kbps peak data rates EDGE 200 KHz carrier Data rates up to 384 Kbps 8-PSK modulation Higher symbol rate HSCSD HSCSD Circuit-switched data 64 Kbps peak data rates

More Revenue : By providing more than a mobile connection. Also operator can charge on the basis of type and amount of content accessed. Huge Potential Market for Data Sevices : Mobile Phone and Internet, both are fastest growing technologies and GPRS is the merger of two. Fast Roll-out and Continuous Network Expansion : GPRS is an integral part of GSM. GPRS uses excess voice capacity for data : GPRS Packets are transmitted in short, free periods between busy hour calls.

8 Free GSM Capacity GPRS packets can be transmitted in
2 4 6 8 10 12 14 16 1:00 PM 1:15 PM 1:30 PM 1:45 PM TCH 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00 TC H GPRS packets can be transmitted in the short free periods between busy hour calls 2TRX = 14 Speech TS 2% blocking means 8 Erlang speech traffic Ø On average 6 TS free !

9 GPRS Vs GSM GPRS Vs GSM 1. SUPPORTS BOTH CKT. Only circuit switched.
SWITCHED as well as packet switched service. 2. MS Utilizes Automatic No re-transmission is retransmission (ARQ) at provided. data link layer to re-transmit error frames. 3. Multiple time slots can be Single time slot per user. allotted to a single user 4. One time slot can be allotted Single time slot per user. to several users. 5. Charging/ billing more complex Simple time-based billing. (Volume based, Q.O.S. based)

10 TYPICAL GPRS SERVICES * Communications- E-mail, fax,
intranet/ internet access. * Value added services Information services, games, e-commerce. * Location-based applications - Navigation, traffic conditions, airline/rail schedule, location finder. * Vertical applications Freight delivery, fleet management, sales-force automation * Location sensitive A user nearing a cinema hall or Advertising a restaurant receives flashes of advertisement


12 The Main elements of GSM are:
GSM NETWORK ELEMENTS The Main elements of GSM are: NSS : MSC VLR HLR (Includes Authentication Center and Equipment Identity Register) BSS : BSC BTS Transcoder NMS Fault Management Configuration Management Performance Management

13 GPRS Network Elements Network Element Software Hardware
SGSN SG1 DX Platform GGSN G1 IP650 Firewall Checkpoint IP650 Ethernet Switch N/A Cisco Catalyst DNS HP-UX HP 9000 A class CG HP-UX HP K class Border Gateway BGP IP650 DHCP HP-UX HP 9000 A class


15 GPRS Interface

16 SGSN Role Authentication, Authorization GTP tunneling to GGSN
Ciphering & compression Mobility Management Session Management Interaction with HLR, MSC/VLR Charging & statistics NMS interfaces

17 GGSN Role Interface to external data networks
Encapsulate in GTP and forwards end user data to right SGSN Routes mobile originated packets to right destination Filters end user traffic Collects charging and statistic information for data network usage


19 Different GPRS Capacity Types
Circuit Switched TRX 1 CCCH TS TS TS TS TS TS TS Territory TRX 2 Packet TS TS TS TS TS TS TS TS TS TS TS TS Switched Territory Additional Dedicated GPRS GPRS GPRS Capacity Capacity Capacity Territory border moves based on Circuit Switched traffic load


21 MS Class CLASS A: Supports simultaneous attach, simultaneous activation, simultaneous monitor, simultaneous invocation, and simultaneous traffic. CLASS B: Simultaneous traffic shall is not supported. The mobile user can make and/or receive calls on either of the two services sequentially but not simultaneously. The selection of the appropriate service is performed automatically CLASS C: Supports only non-simultaneous attach. Alternate use only. The status of the service which has not been selected is detached, that is, not reachable.

22 GPRS Channel Coding Schemes
GPRS can also increase the data rate in a single timeslot. The coding schemes listed above are based on the current scheme used for GSM signaling channels (notice a single slot rate of 9.05 in CS1 as opposed to the TCH data rate of 9.6 in GSM). To increase the data rate, some of the error detection and correction bits are removed from the burst. So CS2 has less C&D bits than CS1, and CS4 has no error protection at all. The consequences of this are that to maintain a call in CS4 it is necessary to have excellent signal quality. This can only be achieved at positions closer to the BTS. Therefore, the cell radius is greatly reduced when using CS3 and CS4. The BSS automatically upgrades and downgrades the connection among the coding schemes based on the number of erroneous packets it receives. In the first release of GPRS, only CS1 and CS2 are implemented. This is because CS3 and CS4 require structural changes to the Abis interface. These data rates will not fit into a 16kbit/s channel.


24 Mobility Management State
GPRS Attach / Detach Idle Ready READY Timer Expiry Packet Standby STANDBY TX/RX Timer Expiry MS location known to MS location known to cell level. MS location SGSN level. MS is transmitting or has not known. MS is capable of receiving just been transmitting. Subscriber is not Point-to-Multipoint data MS is capable of receiving reachable by the and being paged for Point-to-Point data and GPRS NW. Point-to-Point data Point-to-Multipoint data.

25 Routing Area RAI = MCC+MNC+LAC+RAC

26 GPRS Mobility Management
Routing Area : The RA is a new concept for tracing the MS location. Cell =< RA =< LA served by one SGSN RAI = MCC + MNC + LAC + RAC Every time the MS sees the new RAI is has to initiate the RA update procedure.

27 GPRS Mobility Management
Mobility Management States : The IDLE State is when the MS is not connected. The Standby State is when the MS is connected to the GPRS Network The Ready State is when the MS is ready to connect to the external IP Network. Changing between states can be initiated from the MS, from the network and from the timers set.


29 PDP Context Activation Accessing the HLR
(1) MS sends "Activate PDP Context Request" to SGSN Access Point Name PDP Type (IP) PDP Address (empty == dynamic) HLR 2. BTS BSC SS7 1. (2) SGSN checks against HLR Access Point Name Dynamic / static IP address APN= "" SGSN DNS GPRS Backbone IP Network Access Point Intranet GGSN Internet Access Point Name = Reference to an external packet data network the user wants to connect to

SECURITY IN GPRS GPRS SYSTEM HAS INHERITED THE GSM PH-2 SECURITY FUNCTIONS Authentication of the subscriber IMEI Checking User Identity Confidentiality (TMSI in GSM, P-TMSI in GPRS) Ciphering of the data traffic between MS and SGSN Private IP Addressing in the GPRS backbone. Ciphered links and authentication between nodes in the GPRS Backbone. Screening of packets coming from the external networks (Firewall). (P-TMSI is used to derive the Temp Logical Link Identity (TLLI)) ADDITIONAL GPRS SECURITY FEATURES ARE

31 EGPRS = GPRS + EDGE modulation
The Abbreviation GPRS = General Packet Radio System EGPRS = GPRS + EDGE modulation

32 EDGE – Provide 3G services today
Provide 3G services with existing licenses New modulation optimized for wireless data services Link adaptation: Take highest possible rate Covered by existing GSM licenses Same channel structure, network infrastructure, frequency planning and protocol as today’s GSM

Gd AUC M S BTS PUC BSC MSC/VLR Gr ISP Network Gs Gb EDGE TRU M S Gi SGSN GGSN Gn Gn CorporateNetwork Backbone Network

34 EDGE increases capacity
voice voice voice voice voice Standard GSM Transceiver voice voice voice voice voice Free TS Free TS Data EDGE Transceiver

35 System upgrade for EDGE
EDGE TRU B S C R B S BSC Software Upgrade EDGE enabled RBS

36 What EDGE would mean to subscribers
Streaming Applications Very high speed downloads Corporate Intranet connections Quicker MMS Video Phone Vertical corporate applications – Video Conference, Remote presentations

37 Thank You!

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