文档介绍：G Mobile technologies
HSCSD - High Speed Circuit Switched Data
GPRS - General Packet Radio Service
EDGE - Enhanced Data Rates for GSM Evolution
HSCSD
HSCSD is circuit switched technology
All today's works are circuit switched
A physical channel is assigned for the duration of the call
Physical channel connection is maintained even if data is not veing transferred
GPRS
GPRS is a packed switched technology
This is very different to today's work architectures
A physical channel is only assigned when data needs to ve transmitted or received
Physical channels can be shared between different mobile users
GPRS User & Network Operator benefits
User benefits
171Kbps theoretical maximum data transfer rate
Users can transfer data on more than one timeslot
Multiple users share timeslots
Users have an IP address
On-line, all the time
Pay only for data transferred
Network operator benefits
More efficient - every burst can be filled with data
Cleaner air interface - new power contril capabilities
Ability to offer high-speed data over GSM
1 GSM/GPRS Frame
PBCH
PDTCH
Downlink
Uplink
GPRS technology
Packed-based, wireless data service
Uses existing GSM air interface
Adds two s:
Serving GPRS Support Node (SGSN)
Gateway GPRS Support Node (GGSN)
GPRS Interface
s and Links
Ga Charging data collection interface between a CDR transmitting unit (., an SGSN or a GGSN) and a CDR receiving functionality (a CGF).
Gb Interface between an SGSN and a BSS.
Gc Interface between a GGSN and an HLR.
Gd Interface between a SMS-GMSC and an SGSN, and between a SMS-IWMSC and an SGSN.
Gf Interface between an SGSN and an EIR.
Gi Reference point between GPRS and an external packet work.
Gn Interface between two GSNs within the same PLMN.
Gp Interface between two GSNs in different PLMNs. The Gp interface allows support of work services across areas served by the co-operating GPRS PLMNs.
Gr Interface between an SGSN and an HLR.
Gs Interface between an SGSN and an M