Download - Intro to gsm
Introduction To GSM Network Design
- Shaun Roberts
What is GSM?
• Global System for Mobile Communications • Standard for Second Generation Cellular Networks • Introduced in 1990 by European Telecommunications
Stanards Institue • By 2009 GSM technologies accounted for 3.38 billion
subscribers globally and 83.5 percent of the mobile market share.
Overview
• 850Mhz, 950Mhz, 1800Mhz, and 1900Mhz • Conceived for full duplex voice telephony, the design of
the network was circuit switched. • General Packet Radio Services added packet switching for
data services such as text and internet usage.
Mobile Stations
• Most familiar component • SIM holds International Mobile Subscriber
ID, Auth. Key, User Contacts etc. • Mobile Device + SIM = Mobile Station
Keyboard
Control
Display
Transmit AudioSignal
Processing
Receive AudioSignal
Processing
ChannelDecoding
DeinterleavingMessage
Regenerator
ChannelEncoding
InterleavingMessageGenerator
Ciphering
Ciphering
RFProcessing
RFProcessing
SIMDuplexer
Antenna
ANTENNAASSEMBLY
TRANSMITTER
RECEIVER
TRANSCEIVER UNITCONTROLSECTION
Multiple Access
• Frequency Division Multiple Access • Radio Bands split into Frequency
Channels
Multiple Access (cont.)
• Time Division Multiple Access • Splits each Frequency Channel Into 8
Timeslots
BSS – Base Station Subsystem
• Large number of Base Transceiver Stations connected to Base Station Controllers
• Connect Mobile Station to Network
BTS – Base Transeiver Station • Controls
Transceivers and Antennas
• Each BTS can have 16 TX/RX
• 8 Users per TX/RX
BSC – Base Station Controller
• Manages multiple BTS’s
• Essentially small exchange
NSS – Network and Switching Subsystem
• Mobile Switching Centers and Subscriber Databases
• Manages communication and services
MSC – Mobile services Switching Center • Switches Calls • Provides connection to other
networks • Processing of service
features
HLR/VLR/AuC
• Home Location Register • Visitor Location Register • Authentication Center
GPRS Core Network
• Added packet switching to GSM
• Packet Control Unit, Serving GPRS Support Node, Gateway GPRS Support Node
SGSN – Serving GRPS Support Node GGSN – Gateway GRPS Support Node
Sources
• Eberspacher, J; Bettstetter, Christian; Vogel, Hans-Joerg; Hartmann, Christian. (2009). GSM - Architecture, Protocols and Services. Wiley. Heine, Gunnar. (2003). GPRS : Gateway to Third Generation Mobile Networks (Second Edition). Artech House.
• ETSI TS 100 910 V8.20.0 Technical Specification