gsm training engineer
DESCRIPTION
Just share :DTRANSCRIPT
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prepared by: Engr. Aris Condino 2
ObjectivesObjectivesName the three subsystems of GSM.Explain the mobility concept ( handover, location update, paging ).Describe how mobile originated and mobile terminated calls are handled in GSM.Explain the concept of security.
prepared by: Engr. Aris Condino 3
MobileStation
Air Interface
BaseTransceiverStation
A‐bisInterface
A Interface
Mobile Switching Center
Base StationController
Home LocationRegister
Gateway MSCVisitorLocationRegister
NetworkManagement Subsystem
Base Station Subsystem
Network Switching Subsystem
ShortMessageService Center
prepared by: Engr. Aris Condino 4
GSM subsystemsGSM subsystems
BSC
MSCVLR
GMSCHLR
NMS
MS
BSS
NSS
Air
A
O&M
A-bis
NSS Functions:1. Mobility Management2. Subscriber Data Handling3. Signalling ( towards other network elements )4. Call Control5. Charging6. Locating a subs for mobile terminated calls.
prepared by: Engr. Aris Condino 5
BSC
MSCVLR
GMSCHLR
NMS
MS
BSS
NSS
Air
A
O&M
A-bis
BSS Functions:1. Radio Path Control, BTS and TC control, Sync with MSC.2. Air and A interface signalling, Connection establishment.3. Mobility management, Speech Transcoding4. Collection of Statistical data
GSM subsystemsGSM subsystems
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BSC
MSCVLR
GMSCHLR
NMS
MS
BSS
NSS
Air
A
O&M
A-bis
NMS Functions:1. Fault Management2. Configuration Management3. Performance Management
GSM subsystemsGSM subsystems
prepared by: Engr. Aris Condino 7
Mobile StationWhat is a mobile station?
A device able to access services in a GSM network via the Air interface.
+ =
MobileEquipment
SubscriberIdentityModule Mobile
StationGSM
Network
AirInterface
prepared by: Engr. Aris Condino 8
Mobile EquipmentIMEI (International Mobile Equipment Identification)
prepared by: Engr. Aris Condino 9
Subscriber Identification ModuleIMSI
International Mobile Subscriber IdentityICCID
International Compact Card Identification Unique SIM manufacturing number
prepared by: Engr. Aris Condino 10
MSISDN = CC +NDC +SN
CC = Country CodeNDC = National Destination CodeSN = Subscriber #
IMSI = MCC + MNC + MSIN ( fixed 15 digits )
MCC = Mobile Country CodeMNC = Mobile Network CodeMSIN = Mobile Subscriber Identification #
LAI = MCC + MNC + LAC
MCC = Mobile Country Code (of visiting country)MNC = Mobile Network Code(of serving PLMN)LAC = Location Area Code
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BTS1BSC
1
MSC
VLR1
MSCVLR2
LAI 1
MSB
Loc Up
First time Location Update (1)
HLR
IMSI RequestIMSI
HLR DBMSISDN IMSI VLR Address Sub. Data62+898+8983725 310+02+1234567890 vlr2 services
Loc Up + TMSI
Authen
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MS BSS MSC VLR HLR
LOCATION UPDATE REQUEST
REQUEST SUBS ID
SEND SUBS IDREQUEST SUBS INFO
SEND SUBS INFO
AUTHENTICATION
AUTHENTICATION RESPONSE
HLR UPDATE
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PSTN BTS1BSC
1
MSC
VLR1
MSCVLR2
HLRHLR Enquiry
HLR DBMSISDN IMSI VLR Address Sub. Data62+898+8983725 310+02+1234567890 vlr2 services
VLR DBIMSI MSRN LAI DATA310+02+1234567890 1 services
LAI 1
MSRNPOOL
MSB
IMSI
A
B
Call Establishment (PSTNO‐MT)
MSISDN
MSISDN (B)CC+ NDC + SN63 918 9499247
IMSI = MCC+MNC+MSIN
MSRN = CC+NDC+SN
MSISDN
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PSTN BTS1BSC
1
MSC
VLR1
MSCVLR2
LAI 1
MS
A
B
MSISDN
Call Establishment (MO‐PSTNT)
MSISDN (A)CC+ NDC + SN63 2 5113580HLR
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VLR DBIMSI MSRN LAI Services
2 Speech
BTS1
BTS2BSC
2
BSC1
MSC
VLR1
MSCVLR2
HLR
HLR Enquiry
LAI 1
LAI2
MSRNMS
MSB
IMSIB
C
MSISDN
Call Establishment (MO‐MT)
MSISDN (C)CC+ NDC + SN63 918 9499247
IMSI = MCC+MNC+MSIN
MSRN = CC+NDC+SN
MSISDN
HLR DBMSISDN IMSI VLR Address Sub. Data62+898+8983725 310+02+1234567890 vlr1 services
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BTS1BSC
1
MSC
VLR1MSC
VLR2
LAI 1
MSB
Generic Location Update
TMSI + LAIHLR
Loc Up + new TMSI
TMSI
IMSISecurity Info
Subscriber Info
UpdateDel olddata
Authentication
prepared by: Engr. Aris Condino 17
Handover (1)
MSC/VLR 1 MSC/VLR 2
BSC1 BSC2 BSC3
BTS4BTS3BTS2BTS1
PSTN
HLR
A
BMeasurement Report
prepared by: Engr. Aris Condino 18
Handover (2)
MSC/VLR 1 MSC/VLR 2
BSC1 BSC2 BSC3
BTS4BTS3BTS2BTS1
PSTN
HLR
BI am OK
A
prepared by: Engr. Aris Condino 19
Handover (3)
MSC/VLR 1 MSC/VLR 2
BSC1 BSC2 BSC3
BTS4BTS3BTS2BTS1
PSTN
HLR
B
A
Measurement Report
prepared by: Engr. Aris Condino 20
Handover (4)
MSC/VLR 1 MSC/VLR 2
BSC1 BSC2 BSC3
BTS4BTS3BTS2BTS1
PSTN
HLR
BI am OK
A
prepared by: Engr. Aris Condino 21
Handover (5)
MSC/VLR 1 MSC/VLR 2
BSC1 BSC2 BSC3
BTS4BTS3BTS2BTS1
PSTN
HLR
B
A
Measurement Report
prepared by: Engr. Aris Condino 22
Handover (6)
MSC/VLR 1 MSC/VLR 2
BSC1 BSC2 BSC3
BTS4BTS3BTS2BTS1
PSTN
HLR
BI am OK
A
prepared by: Engr. Aris Condino 23
Handover (7)
MSC/VLR 1 MSC/VLR 2
BSC1 BSC2 BSC3
BTS4BTS3BTS2BTS1
PSTN
HLR
B
A
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AC VLR BTS Air Interface ME SIM
A3
A8A8 A5 A5
A3Authentication
EIR MEIMEI Checking
Ciphering
COMPARINGKi SRES SRES
RAND
KiA3A3
A8Kc Kc
Traffic Traffic
TDMA FN TDMA FN
A8A5 A5
Request of IMEI
Provide IMEI
Encrypted DataEncrypted Data
prepared by: Engr. Aris Condino 25
ObjectivesObjectivesDifferentiate between physical and logical channels.List and describe the twelve different types of logical channels and their functions.Describe how air interface properties affect the transmission of speech between MS and network and explain GSM solutions to these problems.List 3 BSC/BTS connections.
prepared by: Engr. Aris Condino 26
FRAME STRUCTURE1 TDMA Frame = 8 TDMA Time Slots
0 1 2 3 4 5 6 7
4.615 ms
Tail Data F Training DataF TailOr Speech
Flag
3000
57 1 26 1 57 3
Burst 148 bits
156.25 bits 0.577 ms
Basic TDMA frame, timeslot and burst structure
prepared by: Engr. Aris Condino 27
LOGICAL CHANNELSOn every physical channel, a number oflogical channels are mapped. Each logical channel is used for a specific purpose.
11 Logical Channels in the GSM system:
2 are used for Traffic9 are used for Control Signaling
prepared by: Engr. Aris Condino 28
LOGICAL CHANNELSTRAFFIC CHANNELS (TCH)
Full Rate ChannelHalf Rate Channel
CONTROL CHANNELS (with horrible abbreviations!)Broadcast Channels (BCH)
Frequency Correction Channel (FCCH)Synchronization Channel (SCH)Broadcast Control Channel (BCCH)
Common Control Channels (CCCH)Paging Channel (PCH)Random Access Channel (RACH)Access Grant Channel (AGCH)
Dedicated Control Channels (DCCH)Stand alone Dedicated Control Channel (SDCCH)Slow Associated Control Channel (SACCH)Fast Associated Control Channel (FACCH)
prepared by: Engr. Aris Condino 29
CHANNEL CONFIGURATION :
0 7
0 1 2 24 25 0 1 2 49 50
Time Slots and Frames:
Hyperframe = 2048 Superframes
Superframe=26X51 or 51X26 Multiframes
26 Multiframe =120 ms 51 Multiframe =235 ms
TDMA frame = 4.615 ms
prepared by: Engr. Aris Condino 30
Logical Channels, DOWNLINK
COMMON CHANNELS
FCCHSCHBCCH
PCHAGCH
BCH
CCCH
SDCCHSACCHFACCH
TCHTCH
DCCH
TCH
DEDICATED CHANNELS
CHANNEL CONFIGURATION :
prepared by: Engr. Aris Condino 31
Logical Channels, UPLINK
COMMON CHANNELS
RACH CCCH
SDCCHSACCHFACCH
TCHTCH
DCCH
TCH
DEDICATED CHANNELS
CHANNEL CONFIGURATION :
prepared by: Engr. Aris Condino 32
Hey! Don’t shoutat me, lower your
power...
BROADCAST CHANNELSall downlink!
FCCH
SCH TDMA#…BSIC...
BCCH
Hey. I’m aGSM xmitter!
GSM?
GSM!!!
LA…neigbors…cell info…max power...
Ok…ok
prepared by: Engr. Aris Condino 33
COMMON CONTROL CHANNELS
PCH downlink only
Hello! You have a call.
RACH uplink only
Hello! I have to setup a call.
I need SDCCH.
AGCH downlink only
Ok. Use SDCCH.
prepared by: Engr. Aris Condino 34
DEDICATED CONTROL CHANNELSuplink and downlink
SDCCH
SACCHtiming advanceMS power
FACCH
handover
On SDCCH:-call set up signaling-location updating-periodic registration-IMSI attach/detach-SMS-facsimileetc…..
On SACCH-mobile transmits signalstrength on ncell quality
“Don’t shout at me”“I can’t hear you “
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F D T T T T T TS D T T T T T TB D T T T T T TB D T T T T T TB D T T T T T TB D T T T T T TC D T T T T T TC D T T T T T TC D T T T T T TC D T T T T T TF D T T T T T TS D T T T T T TC D A T A T A TC D T T T T T TC D T T T T T TC D T T T T T T
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS74.615 ms
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1 Frame (Downlink ‐ BTS transmit)
1 carrier = 200 kHz
F = FCCHS = SCHB = BCCHC = PCH or
AGCHD = SDCCHA = SACCHT = TCH
R D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D T T T T T TR D A I A I A IR D T T T T T TR D T T T T T TR D T T T T T T
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS74.615 ms
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1 Frame(Uplink ‐Mobile transmit)
1 carrier = 200 kHz
R = RACHA = SACCHT = TCH
prepared by: Engr. Aris Condino 36
0 1 2 3 4 5 6 7
.577 ms
200 KHz
4.615 ms
FCCHSCHBCCHPCHRACHAGCH
SDCCHSACCHCBCH
TCHSACCHFACCH
TCHSACCHFACCH
TCHSACCHFACCH
TCHSACCHFACCH
TCHSACCHFACCH
TCHSACCHFACCH
CHANNEL CONFIGURATION :
prepared by: Engr. Aris Condino 37
Configuration of Signaling Channels:
0 7
Combined Configuration
RTSL 0 = BCCH, SDCCH/4, PCH, AGCH
0 7
Separated Configuration
RTSL 0 = BCCH, PCH, AGCH
RTSL 1 = SDCCH/8
CHANNEL CONFIGURATION :
prepared by: Engr. Aris Condino 38
CHANNEL CONFIGURATION :
f s b b bb f s c c c c c c c c f s t t t t t t t t f s t t t t t t t t f s s s s s s s s sc c c c i
t
0
Downlink
Combined CCCH/SDCCH/4 Multiframe:
t t t rr s s s s r r r r r r r r r r r r r r r r r r r r r r r t t t t t t t t r r t t ts s s s t
50
Uplink
51 TDMA Frame = 235 ms
Channels:
f = FCCH b = BCCH r = RACH i = idles = SCH/SACCH c = CCCH ( either PCH or AGCH )
prepared by: Engr. Aris Condino 39
CHANNEL CONFIGURATION :
0
BCCH/CCCH Multiframe:
f s b b bb f s c c c c c c c c f s c c c c c c c c f s c c c c c c c c f s c c c c c c c cc c c c i
r r r r rr r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r r rr r r r r
50
Downlink
Uplink
51 TDMA Frame = 235 ms
Channels:
f = FCCH b = BCCH r = RACH i = idles = SCH c = CCCH ( either PCH or AGCH )
prepared by: Engr. Aris Condino 40
0 50
Downlink
SDCCH/8 Multiframe:
51 TDMA Frame = 235 ms
t t t t s s s s s s s s s s s s s s s s i it t t t tt t t t t t t t t t t t t t t t t t tt t t t i
1 2 3 4 5 6 7 8
tt tti i is s s s s s s s s s s t t t t tt t t t t t t t t t t t t t t t t t tt t t ts t t t t
Uplink
Channels:
t = SDCCH s = SACCH i = idle
CHANNEL CONFIGURATION :
prepared by: Engr. Aris Condino 41
CHANNEL CONFIGURATION :
Full Rate Traffic Channel ( TCH ) Multiframe:
t t tt t t t t s t t t t t t t t t t t t it t t tt
26 TDMA Frame = 120 ms
Downlink and Uplink
t = TCH s = SACCH i = idle
Channels:
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prepared by: Engr. Aris Condino 43
Idle Mode Task
• PLMN selection
• Cell selection
• Cell reselection
• Location updating.
prepared by: Engr. Aris Condino 44
IDLE MODE
prepared by: Engr. Aris Condino 45
Automatic Mode
• PLMN selection
• Cell selection
• Cell reselection
• Location updating.
prepared by: Engr. Aris Condino 46
Normal Cell Reselection
Cell is consider Suitable if:
• It belong to the same selected PLMN
• Cell is not barred
• It does not belong to location area included in the list of forbidden LA for roaming
prepared by: Engr. Aris Condino 47
Search All RF Channels
Tune to the carrier w/ highest signal strength
Get info (BSIC, BCCH) ‐> ex. BA List
Cell Selection
Cell Selection
3‐5 sec to get the list
prepared by: Engr. Aris Condino 48
Continuous Make Measurement(Neighboring BCCH)
Cell Reselection
BSIC BCCH data
Serving cell ‐ at least every 30 s
Six neighbours at least every 30 s at least every 5 min
Reselect to the best Cell
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