Post on 16-Aug-2015
transcript
GSM-Architecture (2)
MS Mobile StationSIM - Subscriber Identity Module
Basestation SubsystemBTS - Base Transceiving Station BSC - Base Station Controller
Network nodeMSC - Mobile Switching Center Registers
GMSC- Gateway Services Switching Center
GSM-Architecture (3)
RegistersHLR - Home Location Register VLR - Visitor Location Register AUC - Authentication Center EIR - Equipment Identity Register
Further IdentifiersTMSI – Temporary Mobile Subscriber IdentifierIMSI – International Mobile Subscriber Identifier...
GSM - Frequencies
GSM-900:Uplink: 890,2 MHz – 915 MHz (25 MHz)Downlink: 935,2 MHz – 960 MHz (25 MHz)Uplink-Downlink distance: 45 MHz
Frequency Division Multiple Access Channels are 200 kHz wide.124 pairs of channels
Time Division Multiple Access 8 connections each channelTheoretical 124*8 = 992 channel to use.
GSM - Frequencies (2)
GSM-1800:
Uplink: 1725,2 - 1780,4 MHz Downlink: 1820,2 - 1875,4 MHz Uplink-Downlink distance: 95 MHz384 pairs of channels
GSM-Link
Fullrate-Channel (Speech)13 kBit/s
Halfrate-Channel (Speech)6,5 kBit/s
GSM-Data-Channel9,6 kBit/s
GSM-Security
User Authentication(Challenge-Response-Method)
AUC generates RAND -> transfers to MSSIM of MS has secret Key and A3-AlgorithmSIM calculates SRES (signed response) fromRAND -> transfer to AUCAUC has secret Key and A3-AlgorithmAUC calculates SRES too -> compares it withresponseif identical AUC authorizes the network access
HSCSD
Enhancement of GSM StandardChanneloriented Data Service (Channelbundle)New Channelcoding: 14.4 kBit/s
HSCSD
Maximum speed: 57 kBit/sNetto speed: approx. 40kBit/s
Advantage: time based payment=> faster = cheaper
GPRS – Key features
GSM Infrastructure EnhancementPacketoriented Data ServiceAllows IP packets to be sent and received across mobile networksTheoretical maximum speed: 171.2 kbps using all 8 time slots
GPRS – Networking
Information is split into separate but related "packets“GPRS radio resources are used only when users are actually sending or receiving dataMore efficient for Networkoperator
GPRS – Networking (2)
Some time slots on some frequencies are reserved for packet trafficTime slots are dynamically managed by base stationTime slots are divided into several logical channels used for different purposes
GPRS – Networking (3)
GPRS provides QoSGPRS network has to check availability of sevicesAsymmetric channels possible (not for HSCSD)Coding shemes with 0-50% redundancy for error correction
GPRS - Limitations
GPRS does impact a network's existing cell capacity and vice versaLink quality depending on transmission channel (environment)Mobile has to provide channel combining abilities (30 multislot classes)
GPRS - Limitations (2)
Maximum speed can only be achieved if a single user would use all 8 time slots
GPRS - Applications
ChatTextual and visual informationWeb browsingDocument sharing/Collaborate workingEmail
EDGE-Standard
GSM/GPRS-Network EnhancementDatarate compareable to UMTS Network(384 kBit/s and more)Less efficient than WCDMA of UMTS
Based on GSM Multiplexmethod (TDMA/FDMA) Changing GSM Modulation from GPSK to 8PSKMuch cheaper than UMTS(existing network)
EDGE-Standard
GSM/GPRS-Network EnhancementDatarate compareable to UMTS Network(384 kBit/s and more)Less efficient than WCDMA of UMTS
Based on GSM Multiplexmethod (TDMA/FDMA) Changing GSM Modulation from GPSK to 8PSKMuch cheaper than UMTS(existing network)
IMT-2000
1992 ITU issued blueprint about 3rd generation mobile telephony called IMT-2000
2000 meant:Year it was supposed to go into serviceFrequency to operate in MHzBandwidth (up to 2MBit/s)
IMT-2000 (2)
Not ready until 2000 Basic services of IMT-2000 network:
High-quality voice transmissionMessaging (e-mail, fax, sms, chat…)Multimedia (playing music, videos,…)Internet access (surfing)
Standardisation of transmission modes (TD/CDMA)
MS Mobile StationUSIM – UMTS Subscriber Identity Module
UTRAN - UMTS Terrestrial Radio Access NetworkRNS - Radio Network Subsystem
RNC - Radio Network ControllerNode B - Base station
Network nodeUMSC - UMTS Mobile Switching CenterRegisters
GMSC- Gateway Services Switching Center
UMTS – Architecture (2)
UMTS - UTRAN
Complete new NetworkFunctionalities:
Access controlCongestion preventionSecurity relevant tasksHandoverConnection and channel control
UMTS – Radio
Each carrier can operate in one of the following modes:TDD
7 unpaired channels per carrier15 timeslots for optionally up- and/or downlink
FDD12 duplex channels pairs per carrier190 MHz carrier distance (up to downlink)
Dual mode
UMTS – Radio (2)
UMTS Modulation is 4PSKUMTS Multiplexing
Wideband CDMA for air interface.Orthogonal spreadingcode for each user (factor 1-16)Orthogonal scramblingcode between cells (OVSF Codes, Goldcode, Kasamicode)
5 MHz bandwidth
UMTS – Frequencies
Up/Downlink FrequencyUplink: 1920 - 1980MHzDownlink: 2110 - 2170MHz
Own subband for satellite service:Uplink: 1980 MHz to 2010 MHzDownlink: 2170 MHz to 2200 MHz
UMTS
Including QoSOffered data rate targets are:
144 kbits/s satellite and rural outdoor384 kbits/s urban outdoor2048 kbits/s indoor and low range outdoor
UMTS - Advantages
Broad offer of servicesSpeed, variety and user-friendliness of a service significantly improved compared with GSM.Only bearer services are standardizedActual application is called teleservice
UMTS - teleservices
Teleservice created individually by a service provider using bearer services.Only 4 teleservices standardized:
SpeechFaxSMSEmergency call
UMTS - Applications
Fast Internet / IntranetStreaming / Download (Video, Audio)VideoconferencesMultimedia-Messaging, E-MailMobile E-Commerce (M-Commerce)Location Based ServicesMobile Entertainment (Games,…)
References
GSM World:www.gsmworld.com
UMTS World:www.umtsworld.com
Vodafone:http://www.vodafone.de/askd2/D2-Netz/Ubertragungstechnik/Frequenzen_und_Kanaele/frequenzen_und_kanaele.html
TU-Wien:http://www.nt.tuwien.ac.at/mobile/projects/UMTS/en/
References (2)
Mobilfunksysteme [Christian Lüders]
Kommunikationstechnik[Jürgen Göbel]
Mobile Applications[Johannes Maucher]
Computer networks [Andrew S. Tanenbaum]