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A THREE DAYS WORKSHOP ON
ADVANCE MOBILE TECHNOLOGY (GSM)
ICIT GOMAL UNIVERSITY
D.I.KHAN
Resource Person: ASIF QAYUM
MS (Telecom & Networks)
Organized By: M.KHALID HAMID
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
START WITH THE NAME OF START WITH THE NAME OF ALLAHALLAH THE MOST MERCIFULL & MIGHTY THE MOST MERCIFULL & MIGHTY
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Day 1 (section 1)Day 1 (section 1)
Cellular Networks Cellular Networks Cell shapeCell shapeHexagonal CellHexagonal CellCell areaCell areaFrequency spectrumFrequency spectrumFrequency spectrum divisionFrequency spectrum divisionNew standardNew standardFrequency Re-UseFrequency Re-UseCell clusterCell clusterAny QuestionAny Question
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Cellular NetworksCellular Networks
The essential difference between a The essential difference between a cellular and fixed telephony network is cellular and fixed telephony network is that the subscriber’s terminal (the that the subscriber’s terminal (the Mobile Station - MS) is not linked by a Mobile Station - MS) is not linked by a fixed physical connection to the networkfixed physical connection to the network Connection is a radio based wireless Connection is a radio based wireless
connectionconnection
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Cell shapeCell shapeEach cell is serviced by a fixed radio Each cell is serviced by a fixed radio transmitter\receiver known as a “base station” transmitter\receiver known as a “base station” (BS) which is commonly located in the centre (BS) which is commonly located in the centre or corner of a cellor corner of a cell
While often drawn as hexagonal in shape, While often drawn as hexagonal in shape, real cells have no defined shape. The actual real cells have no defined shape. The actual area a cell covers depends on many area a cell covers depends on many parameters:parameters: Transmitter powerTransmitter power WeatherWeather Antenna directivityAntenna directivity
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Hexagonal Cell Cell
2
1
2
3
4
5
6
7
7(Site)X 1(Cell) Re-use
Hexagonal cell
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Cell areaCell area
The area a cell covers typically varies from The area a cell covers typically varies from a very small region in urban areas to quite a very small region in urban areas to quite large regions (around 35 km radius in GSM) large regions (around 35 km radius in GSM) in rural areasin rural areas
Cells are often classified as being:Cells are often classified as being: MicrocellsMicrocells MacrocellsMacrocells Umbrella cellsUmbrella cells Selective (directional) cellsSelective (directional) cells
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Frequency SpectrumFrequency Spectrum
Cellular networks operate within defined Cellular networks operate within defined frequency bands of the spectrumfrequency bands of the spectrum
For example, GSM-900 utilises two 25 MHz For example, GSM-900 utilises two 25 MHz bandsbands 890-915 MHz (Uplink - MS to BS)890-915 MHz (Uplink - MS to BS) 935-960 MHz (Downlink - BS to MS)935-960 MHz (Downlink - BS to MS)
These 25 MHz bands are subdivided into These 25 MHz bands are subdivided into 124 carrier frequencies each spaced at 124 carrier frequencies each spaced at approximately 200 kHz (FDMA)approximately 200 kHz (FDMA)
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Frequency Spectrum divisionFrequency Spectrum division
Not all countries utilise the full 25 MHz and Not all countries utilise the full 25 MHz and within a country the full GSM band must be within a country the full GSM band must be subdivided among several network operatorssubdivided among several network operators
Additional frequency spectrum is allocated in Additional frequency spectrum is allocated in most countries around 1800 MHz (GSM-most countries around 1800 MHz (GSM-1800)1800)
In US, certain operators implement GSM In US, certain operators implement GSM standard on a frequency band around 1900 standard on a frequency band around 1900 MHz (GSM-1900)MHz (GSM-1900)
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
New standardNew standardGSM 900
876 880 890 915 921 925 935 960
GSM 900EGSM RGSM RGSM EGSM
EGSM – Extra 10MHz, therefore total available ARFCN become 174.
RGSM – Extra 15MHz, therefore total available ARFCN become 199.
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Frequency Re-useFrequency Re-use
In a given country with, say, two different In a given country with, say, two different GSM networks will each use half the 124 GSM networks will each use half the 124 (i.e. 62) GSM-900 carriers(i.e. 62) GSM-900 carriers
Clearly, even using TDMA technology this Clearly, even using TDMA technology this is an extremely small number of carrier is an extremely small number of carrier frequencies to support a GSM network in a frequencies to support a GSM network in a complete countrycomplete country
All cellular networks address this problem All cellular networks address this problem by what is termed “frequency re-use”by what is termed “frequency re-use”
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Frequency Re-useFrequency Re-useFrequency re-use means that the same set of Frequency re-use means that the same set of carrier frequencies being used in one cell can be carrier frequencies being used in one cell can be re-used in the network in a different cellre-used in the network in a different cell
However, the cells re-using the same carriers However, the cells re-using the same carriers must not be adjacent as they would interfere with must not be adjacent as they would interfere with one anotherone another
In practice, these cell must be distant from one In practice, these cell must be distant from one another another Typical “re-use distance” is 2.5 to 3 times the cell Typical “re-use distance” is 2.5 to 3 times the cell
“radius”“radius”
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Frequency ReuseFrequency ReuseHow can we reuse frequency?How can we reuse frequency?
1
3
2
1
3
2
1
3
2
1
3
2
1
3
2
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Cell ClustersCell Clusters
Cells in a cellular network are generally Cells in a cellular network are generally “grouped” together into cell clusters“grouped” together into cell clusters
Cellular networks are generally designed as Cellular networks are generally designed as a repeated cluster patterna repeated cluster pattern
The number of cells in a cluster (typically 4,7, The number of cells in a cluster (typically 4,7, 12 or 21) is a trade-off between the traffic 12 or 21) is a trade-off between the traffic capacity in the cluster and its interference capacity in the cluster and its interference with the adjacent cluster of cells (where the with the adjacent cluster of cells (where the same frequencies will be re-used)same frequencies will be re-used)
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Cluster Cluster Cluster of 3,4,7,9 & 12Cluster of 3,4,7,9 & 12
Larger cluster size
Longer distance between interferers
13
42 1
342
13
42
13
42
13
42
k=4
15
4
367
2
15
4
367
2
15
4
367
2
15
4
367
2
k=7
15
4
367
28
9 15
4
367
28
9
15
4
367
28
9
15
4
367
28
9 k=9
15
4
367
28
910
1112 1
54
367
28
910
1112
15
4
367
28
910
1112
k=12
13
2
13
213
2
13
213
2
k=3
Less interferenceBUT
Reduced capacity
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
ANY QUESTIONANY QUESTION
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
DAY1 (SECTION 2)DAY1 (SECTION 2)GSM Cellular StandardGSM Cellular StandardJustification for GSMJustification for GSMMeeting these CriteriaMeeting these CriteriaGSM Network ArchitectureGSM Network ArchitectureMobile Station (MS)Mobile Station (MS)Base station subsystem (BSS)Base station subsystem (BSS)Network Subsystem (NSS)Network Subsystem (NSS)HLR & VLRHLR & VLRAuC & EIRAuC & EIROther Network functionOther Network functionGSM Air InterfaceGSM Air Interface
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
GSM Cellular StandardGSM Cellular StandardAll GSM networks and equipment conform to a All GSM networks and equipment conform to a defined GSM standard issued by ETSI (European defined GSM standard issued by ETSI (European Telecommunications Standard Institute)Telecommunications Standard Institute)
GSM is a second generation or digital cellular GSM is a second generation or digital cellular technologytechnology All transmissions (signalling as well as traffic - speech) All transmissions (signalling as well as traffic - speech)
between MS and BS is by digital modulation of between MS and BS is by digital modulation of frequency carrierfrequency carrier
Currently, the most widely used of several second Currently, the most widely used of several second generation digital cellular telephony standardsgeneration digital cellular telephony standards
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Justification for GSMJustification for GSM
GSM development started in the early 1980s GSM development started in the early 1980s to replace first generation (analogue) cellular to replace first generation (analogue) cellular technologytechnology
The proposed system had to meet certain The proposed system had to meet certain criteriacriteria Good subjective speech qualityGood subjective speech quality Low terminal and network equipment costsLow terminal and network equipment costs Support of international roamingSupport of international roaming Efficient use of available spectrumEfficient use of available spectrum
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Meeting these CriteriaMeeting these CriteriaGSM has been very successful in meeting all of GSM has been very successful in meeting all of these criteriathese criteria Widely used in well over 100 countriesWidely used in well over 100 countries Equipment costs are lowEquipment costs are low Voice, data and new services availableVoice, data and new services available
However,However, Still not a single “global” standardStill not a single “global” standard MS to BS bearer rates are still very slow for non-MS to BS bearer rates are still very slow for non-
voice servicesvoice services
Third generation “global” standard UMTSThird generation “global” standard UMTS
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Air
Internet
PSTN
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BSC
BSC
BSC
BSC
BSC
MSC
IWF
GSM Network ArchitectureGSM Network Architecture
- PPP session termination (learn wireless-specific info. while establishing PPP session. Security and policy are linked.- QoS management - wireless-TCP- Personalization of Content Services depending on the device- PUSH and PULL services for Wireless advertisements- Wireless-Specific Policy Gateway- Wireless-VPNs
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
AUCAUC
MEME SIMSIM
OMCOMC
HLRHLR
MSC/VLRMSC/VLR
BTSBTS BSCBSC
PSTN
MS
NSS
BSS
EIREIR
GSM Network ComponentsGSM Network Components
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Mobile Station—MSMobile Station—MS
ME = Mobile EquipmentME = Mobile Equipment
MS=ME+SIMMS=ME+SIM
SIM = Subscriber SIM = Subscriber Identity Identity
ModuleModule
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Subscriber Identity Module – Subscriber Identity Module – SIMSIM
• International Mobile International Mobile Subscriber Identity (IMSI)Subscriber Identity (IMSI)
• Temporary Mobile Temporary Mobile Subscriber Identity Subscriber Identity (TMSI)(TMSI)
• Authentication Key (Ki)Authentication Key (Ki)• Algorithms A3,A5,A8Algorithms A3,A5,A8
• International Mobile International Mobile Subscriber Identity (IMSI)Subscriber Identity (IMSI)
• Temporary Mobile Temporary Mobile Subscriber Identity Subscriber Identity (TMSI)(TMSI)
• Authentication Key (Ki)Authentication Key (Ki)• Algorithms A3,A5,A8Algorithms A3,A5,A8
GS
M
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
The Base Station
Controller – BSC The Base Transceiver
Station – BTS TRAU
The Base Station
Controller – BSC The Base Transceiver
Station – BTS TRAU
BTSBTS
BSCBSC
TRAUTRAUBSS
MSC
Base Station Subsystem – BSSBase Station Subsystem – BSS
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
BTSBTS
The BTS provide the physical connection The BTS provide the physical connection of an MS to the Network inform of Air of an MS to the Network inform of Air interface “Uinterface “Um m
On the other side towards NSS ,the BTS is On the other side towards NSS ,the BTS is connected to the BSC via the Air interface connected to the BSC via the Air interface “Abis” “Abis” Size of BTS = Today the size is Size of BTS = Today the size is comparable to a mailbox comparable to a mailbox
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
BTS Block DiagramBTS Block Diagram
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Base Station Controller (BSC)Base Station Controller (BSC)BSC forms the center of BSSBSC forms the center of BSS
BSC connect to many BTSs over Abis BSC connect to many BTSs over Abis interfaceinterface
Technically BSC is a small digital Technically BSC is a small digital exchange with mobile-specific extensionexchange with mobile-specific extension
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Architecture of BSCArchitecture of BSC
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Switch MatrixSwitch MatrixIts function is to switch the incoming traffic Its function is to switch the incoming traffic channels (A-interface from MSC) to the channels (A-interface from MSC) to the correct Abis-interface channelscorrect Abis-interface channels
It take care of the relay functionalityIt take care of the relay functionality
It is also used as the internal control bussIt is also used as the internal control buss
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Terminal Control Elements (TCE)Terminal Control Elements (TCE)Abis- interfaceAbis- interface
The connection to the BTSs is establish The connection to the BTSs is establish via the TCEsvia the TCEs
The connection is establish independently The connection is establish independently from BSC central Unitfrom BSC central Unit
The number of TCE depends on the The number of TCE depends on the number of BTSs connected with BSCnumber of BTSs connected with BSC
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
A-interface Terminal Control A-interface Terminal Control ElementsElements
The connection of a BSC to the MSC is The connection of a BSC to the MSC is establish via the A-TCEsestablish via the A-TCEsRemember that every BSC is connected Remember that every BSC is connected to only one MSCto only one MSCSo large number of A-TCEs is needed to So large number of A-TCEs is needed to support the A-interface becoz all the support the A-interface becoz all the payload and signaling data of the entire payload and signaling data of the entire BSC have to be conveyed over this BSC have to be conveyed over this interface interface
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Data Base (DB)Data Base (DB)
The BSC database contain the The BSC database contain the maintenance status of the whole BSSmaintenance status of the whole BSS
It contain the complete BTS operations It contain the complete BTS operations software for all attached BTSs software for all attached BTSs
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Central Module (CM)Central Module (CM)The main task of CM is the Handover The main task of CM is the Handover decisiondecisionIt decide when a Handover should take It decide when a Handover should take placeplaceFor both intra BTS and intra BSC For both intra BTS and intra BSC Handover decision BSC do not required Handover decision BSC do not required the permission of MSCthe permission of MSCOnly for external Handover BSC needs to Only for external Handover BSC needs to involve of MSCinvolve of MSCPower control is also the main task of CM Power control is also the main task of CM
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
TRAUTRAU
The task of TRAU is to compress or The task of TRAU is to compress or decompress speechdecompress speech
It compress speech from 64kbps to It compress speech from 64kbps to 16kbps16kbps
Typically it is located between the BSC Typically it is located between the BSC and MSC but it can be placed between and MSC but it can be placed between BTS and BSCBTS and BSC
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Possible installation site of Possible installation site of TRAUTRAU
The speech compression is intended The speech compression is intended mainly to save resources over the Air-mainly to save resources over the Air-interfaceinterface
It is also suitable to save line costIt is also suitable to save line cost
So to get the most benefit from the So to get the most benefit from the compression,the TRAU would be install at compression,the TRAU would be install at the site of the MSC.the site of the MSC.
The GSM specification also allow the The GSM specification also allow the installation of TRAU b/w the BTS & BSC installation of TRAU b/w the BTS & BSC
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Mobile Switching Center – MSC Home Location Register – HLR Visitor Location Register – VLR Equipment Identity Register – EIR Authentication Center – AUC Inter-Working Function – IWFEcho Cancellor – EC
Mobile Switching Center – MSC Home Location Register – HLR Visitor Location Register – VLR Equipment Identity Register – EIR Authentication Center – AUC Inter-Working Function – IWFEcho Cancellor – EC
AUCAUCHLRHLR
MSC/VLRMSC/VLR
PSTN
NSS
EIREIROMC
BSS
ECEC
IWFIWF
The Network Switching SystemThe Network Switching System
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
NSS HierarchyNSS Hierarchy
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
NSS ArchitectureNSS Architecture
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Mobile Service Switching Mobile Service Switching Center – MSC Center – MSC
Call ProcessingCall Processing Operations and Operations and
Maintenance SupportMaintenance Support Inter-network & Inter-Inter-network & Inter-
workingworking BillingBilling
Call ProcessingCall Processing Operations and Operations and
Maintenance SupportMaintenance Support Inter-network & Inter-Inter-network & Inter-
workingworking BillingBilling
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Home Location Register – HLR Home Location Register – HLR
Subscriber ID (IMSI and Subscriber ID (IMSI and MSISDN)MSISDN)
Current subscriber VLR (current Current subscriber VLR (current location)location)
Supplementary service Supplementary service informationinformation
Subscriber status Subscriber status (registered/deregistered)(registered/deregistered)
Authentication key and AuC Authentication key and AuC functionalityfunctionality
Subscriber ID (IMSI and Subscriber ID (IMSI and MSISDN)MSISDN)
Current subscriber VLR (current Current subscriber VLR (current location)location)
Supplementary service Supplementary service informationinformation
Subscriber status Subscriber status (registered/deregistered)(registered/deregistered)
Authentication key and AuC Authentication key and AuC functionalityfunctionality
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Visitor Location Register – VLR Visitor Location Register – VLR
Mobile Status(IMSI detached/ Mobile Status(IMSI detached/
attached)attached)
Location Area Identity(LAI)Location Area Identity(LAI)
Temporary Mobile Subscriber Temporary Mobile Subscriber
Identity(TMSI)Identity(TMSI)
Mobile Station Roaming Mobile Station Roaming
Number(MSRN)Number(MSRN)
Mobile Status(IMSI detached/ Mobile Status(IMSI detached/
attached)attached)
Location Area Identity(LAI)Location Area Identity(LAI)
Temporary Mobile Subscriber Temporary Mobile Subscriber
Identity(TMSI)Identity(TMSI)
Mobile Station Roaming Mobile Station Roaming
Number(MSRN)Number(MSRN)
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
IMEIIs Checked against White List
IMEIIs Checked against Black/Grey List
If NOT found, checked against Grey/Black List
Equipment Identity Register – Equipment Identity Register – EIR EIR
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
AuthenticationAuthentication
A3A3
=?=?
A3A3
RANDRANDKi Ki
MSMS NetworkNetworkUm interface
Accept / reject?
SRES
SRES
Ki = authentication key
RAND = random number
SRES = Signal Response
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Any QuestionAny Question
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Day1 (section 3)Day1 (section 3)
GSM ChannelsGSM Channels
GSM BurstGSM Burst
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
The physical channel is the medium over which the information is carriedThe logical channels consist of the information carried over the physical channel
The physical channel is the medium over which the information is carriedThe logical channels consist of the information carried over the physical channel
00 1 2 3 4 5 6 7
TDMA FRAME
Timeslot
The information carried in one time slot is called a “burst”
The information carried in one time slot is called a “burst”
Physical and Logical ChannelsPhysical and Logical Channels
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Traffic ChannelTraffic Channel
TCHTraffic Channels
Speech
TCH/FS
Data
TCH/HSTCH/9.6 TCH/2.4
TCH/4.8
Normal Burst
TCH Traffic ChannelTCH/FS Full rate Speech Channel TCH/HS Half rate Speech Channel TCH/9.6 Data Channel 9.6kb/sTCH/4.8 Data Channel 4.8kb/sTCH/2.4 Data Channel 2.4Kb/s
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
FCCHSCH
CCH Control Channels
DCCH
SDCCH
BCCH
BCCH Synch. CH.ACCH
SACCHFACCH CCCH
RACHCBCH
PCH/AGCH
Broadcast Control Channel – BCCHCommon Control Channel – CCCHDedicated Control Channel – DCCHAssociated Control Channel – ACCH
Control ChannelControl Channel
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
GSM MultiframeGSM MultiframeTDMA Frames
0 1
0 1 2 43 21 22 23 2524
26 – Frame Multiframe (120ms)
0 1 10
TRAFFIC CHANNELS
2 3 4 5 6 7 2 3 5 764
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
TDMA Frames
0 1
0 1 2 43 46 47 48 5049
51 – Frame Multiframes (235.3ms)
0 1 10
CONTROL CHANNELS
2 3 4 5 6 7 2 3 5 764
GSM MultiframeGSM Multiframe
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Timeslots and TDMA FramesTimeslots and TDMA Frames
Higher Capacity Cell
Broadcast TrafficDedicated
Traffic00 1 2 3 4 5 6 7
00 1 2 3 4 5 6 7
Low Capacity Cell
Combined Traffic00 1 2 3 4 5 6 7
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
GSM BurstGSM BurstThe timeslots are termed burst periods The timeslots are termed burst periods because the GSM transmitter must transmit because the GSM transmitter must transmit its data in a short “burst” within the time slotits data in a short “burst” within the time slot
Random Access burst (RACH): Used in MS Random Access burst (RACH): Used in MS initial accessinitial accessFrequency correction burst (FCH): Used in Frequency correction burst (FCH): Used in frequency synchronization between MS and frequency synchronization between MS and BTSBTS
• Synchronous burst (SCH): Used in timing Synchronous burst (SCH): Used in timing synchronization between MS and BTSsynchronization between MS and BTS
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
BURST Frame FormatBURST Frame Format
8bit 41 synchronous bits
36 encrypted bits 3bit 68.25bit
Tail bit Tail bit Guard intervalData
• Random Access burst (RACH): Used in MS initial access
Guard interval
3bit 142bit 3bit 8.25bit
Tail bit Tail bitData
• Frequency correction burst (FCH): Used in frequency synchronization between MS and BTS
3bit 39 encrypted bits
39 encrypted bits
3bit 8.25bit
Tail bit Tail bit Guard intervalDataData
64 synchronous bits
• Synchronous burst (SCH): Used in timing synchronization between MS and BTS
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Burst Mapping on physical Burst Mapping on physical channelchannel
Burst (148 bits)Burst (148 bits)Guard
Interval
(8.25 bits)
Guard
Interval
(8.25 bits)
0 7
TDMA frame = 4.615 ms
0
f s7 0
s7
577µs (156.25 bits)
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Any QuestionAny Question
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Day 1 (Section 4)Day 1 (Section 4)
GSM ModulationGSM Modulation
Battery Life Battery Life
IMSIIMSI
TMSITMSI
IMEIIMEI
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Modulation TechniquesModulation Techniques
Amplitude Modulation (AM)
Frequency Modulation (FM)
Phase Modulation (PM)
Phase modulation can be implemented easily
for digital signals, this is the method which is
Used for the GSM air interfaces. Phase
Modulation is known as Phase Shift Keying when
applied to Digital signals.
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Gaussian Minimum Shift Keying (GMSKGaussian Minimum Shift Keying (GMSK))
1 0 0 1 1
Gaussian Digital Filter
GMSK Modulator
Gaussian Minimum Shift Keying
(GMSK)
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
Battery LifeBattery Life
Power Power ControlControl
Power Power ControlControl
Voice Activity Detection – VAD
Discontinuous Transmission – DTX
Discontinuous Reception – DRX
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
MCC : Mobile Country Code , It consists of 3 digits . For example: The MCC of China is "460"。MNC : Mobile Network Code , It consists of 2 digits . For example: The MNC of China Telecom is "00"。MSIN : Mobile Subscriber Identification Number. H1H2H3 S ABCDEF For example: 666-9777001NMSI : National Mobile Subscriber Identification , MNC and MSIN form it
together. For Example of IMSI : 460-00-666-9777001
MCC : Mobile Country Code , It consists of 3 digits . For example: The MCC of China is "460"。MNC : Mobile Network Code , It consists of 2 digits . For example: The MNC of China Telecom is "00"。MSIN : Mobile Subscriber Identification Number. H1H2H3 S ABCDEF For example: 666-9777001NMSI : National Mobile Subscriber Identification , MNC and MSIN form it
together. For Example of IMSI : 460-00-666-9777001
Not more than 15 digits
3 digits 2 digits
IMSI
MCC MNC MSIN
NMSI
IMSI IMSI
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
The TMSI is assigned only after successful The TMSI is assigned only after successful subscriber authentication. subscriber authentication.
The VLR controls the allocation of new TMSI The VLR controls the allocation of new TMSI numbers and notifies them to the HLR.numbers and notifies them to the HLR.
TMSI is used to ensure that the identity of the TMSI is used to ensure that the identity of the mobile subscriber on the air interface is kept mobile subscriber on the air interface is kept secret.secret.
The TMSI consists of 4 bytes( 8 HEX numbers) The TMSI consists of 4 bytes( 8 HEX numbers) and determined by the telecom operator.and determined by the telecom operator.
The TMSI is assigned only after successful The TMSI is assigned only after successful subscriber authentication. subscriber authentication.
The VLR controls the allocation of new TMSI The VLR controls the allocation of new TMSI numbers and notifies them to the HLR.numbers and notifies them to the HLR.
TMSI is used to ensure that the identity of the TMSI is used to ensure that the identity of the mobile subscriber on the air interface is kept mobile subscriber on the air interface is kept secret.secret.
The TMSI consists of 4 bytes( 8 HEX numbers) The TMSI consists of 4 bytes( 8 HEX numbers) and determined by the telecom operator.and determined by the telecom operator.
TMSITMSI
TMSI: Temporary Mobile Subscriber Identification)
A.Q.Khan aA.Q.Khan [email protected]@gu.edu.pk
IMEI (15 digits)IMEI (15 digits)
TAC FAC SNR SP
IMEI
TAC : Type approval code. It is administered by the type approval center.
FAC : Final assembly code.It is administered by the manufacturer.
SNR : Serial number.It is issued by the manufacturer of the MS.SP : Not used.
TAC : Type approval code. It is administered by the type approval center.
FAC : Final assembly code.It is administered by the manufacturer.
SNR : Serial number.It is issued by the manufacturer of the MS.SP : Not used.
IMEI: International Mobile Station Equipment Identification