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General Packet Radio Service

Presented By: Kusum Bharti 082112103. General Packet Radio Service. Maulana Azad National Institute of Technology,Bhopal Department of Computer Science & Engineering. Guided By: Mrs. NAMITA TIWARI. Topics covered. GPRS introduction Goals of GPRS Goals of GPRS Network Elements

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General Packet Radio Service

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  1. Presented By: Kusum Bharti 082112103 General Packet Radio Service Maulana Azad National Institute of Technology,BhopalDepartment of Computer Science & Engineering Guided By: Mrs. NAMITA TIWARI

  2. Topics covered • GPRS introduction • Goals of GPRS • Goals of GPRS • Network Elements • Protocol Stack • Data Packet Routing • Quality of service • Data Packet Routing • GPRS - Network Processes • Applications of GPRS • Benefits of GPRS • Limitation of GPRS • Conclusion

  3. Constraints with existing network • Data Rates too slow – about 9.6 kbps. • Connection setup time too long. • Inefficient resource utilization for bursty traffic. • Proves expensive for bursty traffic utilization. • No efficient method for packet transfers

  4. What is 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 applies packet radio principal to transfer user data packets in an efficient way b/w MS & external packet data network .

  5. Comparison of GSM & GPRS

  6. Goals of GPRS • Open architecture • Consistent IP service. • Same infrastructure for different air interface. • Integrated telephony and internet infrastructure . • Service innovation independent of infrastructure.

  7. GPRS Classes • Class A • Class B • Class c

  8. GSM to GPRS

  9. HLR (Home location Register) • Shared database with GSM • Is enhanced with GPRS subscriber data and routing information • For all users registered with the network,HLR keep user profile, current SGSN and packet data protocol(PDP) addresses information • SGSN exchanges information with HLR e.g. inform HLR of the current location of the MS. • When MS register with a new SGSN,the HLR sends the profile to the new SGSN

  10. VLR(Visitor Location Register) • VLR is responsible for a group of location areas. It stores data of only those users in its area of responsibility. • MSC/VLR can be enhanced with function and register entries that allow efficient coordination between GPRS and GSM services combine location updates combine attachment procedures

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

  12. 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 change 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

  13. 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

  14. GPRS Register • Maintains the GPRS subscriber data and Routing information. • Stores current SGSN address. • GPRS Register is integrated with GSM-HLR

  15. Interfaces • Gn – SGSN – SGSN/GGSN (in the same network). • Gp – SGSN –GGSN (in different networks). • Gi – Connects PLMN with external Packet Data Networks (PDNs). • Gf – For equipment querying at registering time • Gr – To exchange User profile between HLR & SGSN • Gs – To exchange Database between SGSN & MSC • Gd – Interface between SMS & GPRS • Gb – Connects BSC with SGSN.

  16. GPRS architecture reference model SGSN Gn Gb Gn PDN MS BSC SGSN GGSN UM Gi Gc Gs Gr MSC HLR Gf VLR EIR

  17. Protocol Stack IP / X.25 SNDCP GTP GTP UDP/ TCP UDP/ TCP LLC LLC LLC RLC RLC BSSGP BSSGP IP IP Frame Relay Frame Relay MAC MAC L2 L2 GSM RF L1bis L1bis L1 L1 MS BSS (PCU) SGSN GGSN Gi Application IP / X.25 SNDCP GSM RF Gb Gn Um

  18. Data Link layer • Divided into two sub layers : • LLC layer (between MS-SGSN) • RLC/MAC (between MS-BSS)

  19. LLC-Logical Link Control • Establishes highly reliable logical link between MS & its assigned SGSN • Works either in acknowledged or unacknowledged modes • Data confidentiality is ensured by ciphering functions

  20. RLC/MAC Layer • Radio Link Control(RLC) • Establish a reliable link between MS & BSS Medium Access Control(MAC) • Segmentation and reassembly of LLC frames into RLC data blocks • Medium Access Control(MAC) • Controls access attempts of an MS on radio channels shared by several MSs • Both ack and unpack. Modes of operation are supported in RLC/MAC layer

  21. Physical Layer • Divided into two sub layers : 1. Physical Link Layer (PLL) 2. Physical RF Layer (RFL) • PLL – Provides a physical channel between MS and BSS • RFL - Operates below PLL

  22. SNDCP-Sub Network DependentConvergence Protocol • Used to transfer data packets between SGSN and MS. • Multiplexing of several connection of network layer onto one logical connection of underlying LLC layer. • Compression and decompression of user data and header information

  23. BSSGP-(BSS GPRS Application Protocol) • Delivers routing & Quality of Service related information between BSS and SGSN

  24. Data Packet Routing • Mobile oriented message • Network initiated message when MS is in home • Network initiated message when MS roam to another GPRS network

  25. When MS is transmitting • At MS,IP datagram is compressed and encapsulated into an SNDCP ,that is sent through LLC,RLC/MAC and RF to the serving GSN. • When SGSN receives the data, it tunnels the packet to the reference GGSN through the GPRS backbone. • GGSN removes the tunneling and forward the IP datagram to the internet that delivers the data to final destination.

  26. When MS is receiving • The corresponding host sends the IP datagram to a GPRS MS using the MS’IP address. • Internet routing protocols are used to route data to MS’ subnetwork. • GGSN extracts MS’s IP address and maps it to MS’s current location. • GGSN tunnels the packet through the GPRS backbone to the SGSN serving the MS.

  27. Contd. • SGSN removes the tunneling,encapsultes the IP datagram into an SNDCP and forwards it to BSS. • Packet is sent to MS through LLC,RLC/MAC and RF

  28. When MS is in roaming • MS from PLMN-2 is visiting PLMN-1 • IP address prefix of MS is the same as GGSN-2 • Incoming packets to MS are routed to GGSN-2 • GGSN-2 queries HLR and find that MS is currently in PLMN-1 • It encapsulates the IP packets and tunnels them through the GPRS backbone to the appropriated SGSN of PLMN-1 • SGSN decapsulates and delivers to MS.

  29. DATA CALL ROUTING BSC BSC BTS BTS MS inter-PLMN GPRS backbone Gn SGSN Gp SGSN Border gateway intra-PLMN GPRS backbone Border gateway Intra-PLMN GPRS backbone PLMN1 Gn Gn PLMN2 Gi GGSN GGSN External Packet data network(PDN) Host SGSN Router LAN

  30. SESSION MANAGEMENT IN GPRS

  31. Attachment & Detachment Procedure • GPRS attach • User is registered in SGSN, after authentication check from HLR • GPRS detach • Disconnection of MS from GPRS network is called GPRS detach • It can be initiated by MS or by network(SGSN or HLR)

  32. Session Management • Mobile Station applies for PDP address • For each session PDP context is created & it contains • PDP type • PDP address assigned to MS • Requested QoS • Access point • With active PDP context MS able to send or receive data packets • Allocation of PDP address can be static or dynamic

  33. PDP Context Activation MS SGSN GGSN Activate PDP Context Request PDP type,PDP Address QoS Requested,Access Point,… Security Functions Create PDP Context Request PDP type,PDP Address QoS Negotiated,Access Point,… Create PDP Context Response Activate PDP Context Accept PDP type,QoS Negotiated,… PDP type,PDP Address QoS Negotiated,…

  34. LOCATION MANAGEMENT IN GPRS

  35. State Model of GPRS MS

  36. GPRS - Network Processes • Attach process: • Authentication process: • PDP activation process: • Detach process: • Network-initiated PDP request for static IP address: • Network-initiated PDP request for dynamic IP address:

  37. Quality of service • Service Precedence: • Reliability: • Probability of loss • Duplication • Mis-sequencing • Corruption of packet

  38. Delay • Throughput

  39. Applications of GPRS • Web browsing • Corporate & Internet Email • Still Images • Remote LAN Access • Home Automation • Document Sharing/Collaborative working • Mobility • Immediacy • Localization

  40. GPRS in INDIA • Hutchison Essar • Idea Cellular • Hutchison Max • Bharti Cellular • BPL Mobile • Reliance Mobile

  41. 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. • Easy Billing.

  42. Limitation of GPRS • Limited cell capacity for all users • Speed much lower in reality • Transit delays • No store and forward

  43. To sum up, GPRS improves the utilization of the radio resources, offers volume-based billing, higher transfer rates, shorter access times, and simplifies the access to packet data networks. Conclusion

  44. What is Next ? • Enhanced Data rate for GSM Evolution (EDGE): • Universal Mobile Telecommunication System (UMTS):

  45. Thank you

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