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GPRS Overview

GPRS Overview. Kwak Min Seok Samsung Electronics R & D 3Group Mobile Communication Division. Contents. GPRS overview Features Applications GPRS System Arcitecture Overview GPRS Mobile Operation Attach/Dettach PDP Context Activation GPRS Mobile States GPRS Mobile Class

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GPRS Overview

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  1. GPRS Overview Kwak Min Seok Samsung Electronics R & D 3Group Mobile Communication Division GPRS Overview

  2. Contents • GPRS overview • Features • Applications • GPRS System Arcitecture Overview • GPRS Mobile Operation • Attach/Dettach • PDP Context Activation • GPRS Mobile States • GPRS Mobile Class • S/W architecture GPRS Overview

  3. GPRS Features • Sits on existing GSM network • Many users – Multiflexing • Packet Switched • Uses a packet mode technique • Fast switching of Resources • Interworking compatible with other Data networks • TCP/IP, X.25, etc • High data rates – 171.2kbps • Supports a wide range of Applications • Quality of Service • Charging is based on the amount of data transferred GPRS Overview

  4. GPRS Applications • Mobile office Applications • Internet • Web browsing, File transfer,… • Online banking • Moving or still images • Upload, Download • Traffic information • Vehicle positioning • GPS • Information Services • News,Ticketing,… GPRS Overview

  5. BTS HLR VLR AUC MS BTS BSC PSTN BTS ISDN MSC CSPDN A MS BTS PSPDN BTS BSC OMC Abis TE BTS Um Basic GSM System Architecture GPRS Overview

  6. MS MSC/VLR HLR Gs Gr BTS BSC PCU IP SGSN GGSN Gb Gn MS X.25 BTS BSC PCU Um TE BSS Basic GPRS System Architecture GPRS Overview

  7. BTS BSC PCU SGSN GGSN Gn Gb MS Application IP / X.25 IP / X.25 Relay SNDCP GTP SNDCP GTP LLC LLC UDP / UDP / TCP TCP Relay RLC BSSGP RLC BSSGP IP IP MAC MAC Network Network L2 L2 Service Service GSM RF GSM RF L1bis L1bis L1 L1 Gb Gn Um Gi MS BSS SGSN GGSN GPRS Transmission Plane MS GPRS Overview

  8. Basic GPRS System Architecture • SGSN : The Serving GPRS Support Node (SGSN) • Same hierarchical level as the MSC • Serves attached mobiles • keeps track of the individual MSs' location and performs security functions and access control. • Connected to the BSS with Frame Relay(in future, ATM) • Data/packet Counting(for charging) GPRS Overview

  9. Basic GPRS System Architecture • GGSN : The Gateway GPRS Support Node • Interworking with external packet-switched networks • Connected with SGSNs via an IP-based GPRS backbone network. • The HLR is enhanced with GPRS subscriber information • Enhanced MSC/VLR : co-ordination of GPRS and non-GPRS services (paging , LA) • PCU : Packet Control Unit • Packet Segmentation • Radio Channel Allocation • QoS measurements GPRS Overview

  10. GPRS Attach/Dettach • Establishes a logical link between the MS and the SGSN • Performed when a mobile indicates its presence to the network, for the purpose of using the services provided by the network • Dependent upon the class of the mobile • IMSI attach for GSM circuit switched(CS) services • GPRS attach • Combined IMSI/GPRS attach GPRS Overview

  11. PDP Context Activation • PDP Context • Contains mapping and routing information btw. MS & GGSN • Activation • Allocation of PDP Address • Access point name(APN) • Quality of service required(QoS) • Priority (for packet transfer) • Reliability (of connection, I.e. loss of data) • Delay (within the network) • Throughput (data/time) GPRS Overview

  12. Idle GPRS Attach GPRS Dettach Ready Ready timer expiry or Force to Standby PDU Transmission Standby GPRS Mobile States GPRS Overview

  13. Mode Attached to Support Class A Both GPRS and GSM services Simultaneous attach • monitor • traffic Class B Both GPRS and GSM services Only operate one set of services at a time Class C Either GPRS or GSM services Alternate use only GPRS Mobile Class • Modes of operation GPRS Overview

  14. GPRS Attach makes the MS known in the corresponding GGSN Encapsulation & Tunneling data Packets are equipped with GPRS-specific protocol information and transferred between MS and GGSN BTS BSC PCU SGSN GGSN PDNs Gn Gb 1. GPRS Attach 2. PDP Activation 3. Data Transfer Encapsulation & Tunneling PDP Activation establishes a logical link between MS and SGSN GPRS Operation GPRS Overview

  15. GPRS Logical Channel Logical Channel Signaling Channels Traffic Channels Packet Traffic Channel Packet Broadcast Control Channel Packet Common Control Channel Downlink Uplink PDTCH PBCCH PRACH Downlink & Uplink Downlink PACCH PPCH Downlink PAGCH Downlink PNCH GPRS Overview

  16. Packet Signaling Channels – control • Packet Broadcast Control Channel (PBCCH) • Broadcasts in the downlink direction packet data System Info’s. • If not allocated, the info’s are broadcasted on the BCCH. • Packet Common Control Channel (PCCCH) • Comprises of the following packet logical channels for common control signaling : • PCCCH=PPCH+PRACH+PAGCH+PNCH • Packet Paging Channel (PPCH) • Used to page a mobile prior to downlink packet transfer. • Uses paging groups in order to allow usage of DRX mode. • Can be used for paging of both circuit switched and packet data services. GPRS Overview

  17. Packet Signaling Channels – control • Packet Access Grant Channel (PAGCH) • Used in the packet transfer establishment phase (downlink only) to send resource assignment to a mobile prior to packet transfer. • Packet Notification Channel (PNCH) • Used to send a PTM-M (Point To Multipoint - Multicast) notification to a group of mobiles prior to a PTM-M packet transfer. • Packet Random Access Channel (PRACH) • Used by the mobile to initiate uplink transfer for sending data or signaling information. • Packet access and extended packet access bursts are used on the PRACH. GPRS Overview

  18. Packet Traffic Channels • Packet Data Traffic Channel (PDTCH) • Allocated for data transfer. In multislot operation, one MS may use multiple PDTCHs in parallel for individual packet transfer. • All packet data traffic channels are uni-directional, either uplink (PDTCH/U), for a mobile originated packet transfer or downlink (PDTCH/D) for a mobile terminated packet transfer. • Packet Associated Control Channel (PACCH) • Conveys signaling information related to a given mobile. • Shares resources with PDTCHs that are currently assigned to the mobile. • A mobile that is currently involved in packet transfer can be paged for circuit switched services on the PACCH. GPRS Overview

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