General Packet Radio Service An Overview Ashish Bansal

General Concepts Packet mode technique for xmitting high speed and low speed data and signaling New GPRS radio channels with flexible allocation Four different QoS levels are defined MS can operate in 3 different modes of operation Two new nodes - SGSN and GGSN

GSM and GPRS Architecture

GPRS Layers

GPRS Layers contd... GPRS Tunneling Protocol (GTP): for tunneling data and signaling between GSNs in the network. GPRS Mobility Management and Session Management (GMM/SM): for GPRS attach, GPRS detach, security, routeing area update, location update, PDP context activation and deactivation Subnetwork Dependent Convergence Protocol (SNDCP): Maps different packet data protocols (like IP, X.25) to a common level. Logical Link Control (LLC): provides highly reliable ciphered logical link. Relay: Exists on BSS and SGSN. Responsible for mapping LLC PDUs between Um and Gb interfaces. In SGSN maps between Gb and Gn interfaces. Base Station System GPRS Protocol (BSSGP): For conveying routing and QoS related information between BSS and SGSN. Network Service (NS): For transporting BSSGP PDUs. Based on frame relay. Radio Link Control/Medium Access Control (RLC/MAC): RLC provides radio-solution dependant reliable link. MAC controls request and grant procedures for the radio channel and mapping of LLC frames onto GSM channels..

GPRS Operation GPRS Attach PDP Context Activation Data transfer PDP Context Deactivation/GPRS Detach

GPRS Attach

GPRS Attach contd...

PDP Context Activation

GPRS Data Transfer

GPRS Detach

References C Bettstetter, H Vogel, J Eberspacher, “GSM Phase 2+ General Packet Radio Service GPRS: Architecture, Protocols, and Air Interface”, IEEE Communications Survey, vol. 2 no. 3, pp 2-14, IIIrd quarter GSM GPRS Service Description GSM BSS GPRS Protocol GSM Mobile radio interface Layer 3: General Aspects See