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

Contents GPRS overview GPRS System Arcitecture 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

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

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

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

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

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

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

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

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

PDP Context Activation 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

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

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

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

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

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

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

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