gsm network.ppt
DESCRIPTION
GSM network.pptTRANSCRIPT
Communication Engineering
Eng.Mohyee MikhemarAin Shams University
Aug 2002
GSM Network Mohyee Mikhemar 2002 2
Contents
Introduction
Cellular concepts
GSM network
GSM protocol
Circuit Realization
GSM Network Mohyee Mikhemar 2002 3
GSM Network Features:
Roaming. ISDN capability. Use of SIM card. Control of transmission power. Frequency hopping. Discontinuous transmission. Mobile-assisted handover
GSM Network Mohyee Mikhemar 2002 4
GSM Architecture
OMS
MS BSS SS
Operation and Maintenance subsystem
Switching Subsystem
Base Station subsystem
Mobile Station
GSM Network Mohyee Mikhemar 2002 5
Mobile Station Mobile Equipment
Handset Identity code (32 bit). SIM card: Subscriber Identity Module
IMSI: International Mobile Subscriber Identity (34 bit).
Ki: Identity and Authentication key Kc: Ciphering key A3 , A5 , A8: Ciphering Algorithms
GSM Network Mohyee Mikhemar 2002 6
Base Station Subsystem BTS: Base Transceiver station
3 Antennas: 2 Rx & 1 Tx. Microwave link with the network
BSC: Base station controller Control many (BTS) It handles many functions:
Channel Allocation Link quality Supervision
GSM Network Mohyee Mikhemar 2002 7
Base Station Subsystem Transmission of broadcast messages Controlling power level Controlling frequency hopping Error correction coding and decoding Hardware processing Data and signaling encryption Digital speech transcoding Data rate adaptation
GSM Network Mohyee Mikhemar 2002 8
Switching Subsystem
MSCHLR
VLR
GMSC
AUCEIR
GIWU
MSC:Mobile Service Switching center Co-ordinates call setup One MSC control several BSC
GSM Network Mohyee Mikhemar 2002 9
Switching Subsystem
MSCHLR
VLR
GMSC
AUCEIR
GIWU
HLR:Home Location Register Database of all subscribers information
GSM Network Mohyee Mikhemar 2002 10
Switching Subsystem
MSCHLR
VLR
GMSC
AUCEIR
GIWU
AUC:Authentication center Manage the security data for subscriber authentication
GSM Network Mohyee Mikhemar 2002 11
Switching Subsystem
MSCHLR
VLR
GMSC
AUCEIR
GIWU
EIR:Equipment Identity Register Database of all Mobile Equipments
GSM Network Mohyee Mikhemar 2002 12
Switching Subsystem
MSCHLR
VLR
GMSC
AUCEIR
GIWU
VLR:Home Location Register Database of all visitors information
GSM Network Mohyee Mikhemar 2002 13
Switching Subsystem
MSCHLR
VLR
GMSC
AUCEIR
GIWU
GMSC:Gateway MSC Gateway to the PSTN
GSM Network Mohyee Mikhemar 2002 14
Switching Subsystem
MSCHLR
VLR
GMSC
AUCEIR
GIWU
GIWU:Gateway Networking Unit For Communication with users outside GSM
GSM Network Mohyee Mikhemar 2002 15
OMS
Operation and Maintenance
Subsystem: Network operation and maintenance
Subscription management: charging
and billing.
Mobile equipment management
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Spectrum Sharing
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FDD
890 915 935 960
Uplink Downlink
MS
BS
MS
BS
MHz
Total Band=25 MHz
f Att.
Atteunation f
GSM Network Mohyee Mikhemar 2002 18
FDM
890 915 935 960Uplink Downlink
124 Carrier 200KHz apart
MHz
Ch1F=890M+100k
Ch2F=890M+300k
Ch124F=915M-100k
GSM Network Mohyee Mikhemar 2002 19
FDM
890 915 935 960Uplink Downlink
124 Carrier 200KHz apart
MHz
Ch1F=890M+100k
Ch2F=890M+300k
Ch124F=915M-100k
Channel Spacing 200 KHz
Guard Band 100 KHz
GSM Network Mohyee Mikhemar 2002 20
FDM
890 915 935 960Uplink Downlink
124 Carrier 200KHz apart
MHz
Ch1(up)F=890M+100k
Ch1(Down)F=935M+100k
GSM Network Mohyee Mikhemar 2002 21
TDMA
Every channel is shared among 8
users
There are 124 Carriers each
shared among 8 users.
A User is assigned a certain time
slot on a certain carrier (Cn,TSk)
GSM Network Mohyee Mikhemar 2002 22
(Cn,TSk)
C0
C1
C123
f
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 t
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 t
TS1 TS2 tTS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0
Frame
GSM Network Mohyee Mikhemar 2002 23
(Cn,TSk)
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 tC12
( C12,TS2 )
GSM Network Mohyee Mikhemar 2002 24
Channels Space (Copy Right)
Frame No
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
f
C0
C1
C2
C3
GSM Network Mohyee Mikhemar 2002 25
Channels
Physical Channel: It’s a time slot on any carrier (Cn,TSk).
Logical Chaneel: It’s a channel mapped on a physical
channel to do a certain job
GSM Network Mohyee Mikhemar 2002 26
Channel Types
Traffic Channels (TCH) Used after call setup for transmission
of speech.
Control Chaneels (CCH) Over head channels used for network
administration and SMS.
GSM Network Mohyee Mikhemar 2002 27
Control Channels
Broadcast Channels
Common Control Channels
Dedicated Channels
GSM Network Mohyee Mikhemar 2002 28
Control Channels
Broadcast Channels
Common Control Channels
Dedicated Channels
GSM Network Mohyee Mikhemar 2002 29
Control Channels
Broadcast Channels (FCCH): Frequency Correction Channel
No Data just pure carrier (SCH): Synchronization Channel
Broadcast Mobile Network Identity Code Broadcast Base Station Identity Code Broadcast Current frame number
(BCCH): Broadcast Control Channel Broadcast location area Identity Broadcast maximum output power Broadcast C0 of neighboring cells
GSM Network Mohyee Mikhemar 2002 30
Control Channels
Broadcast Channels
Common Control Channels
Dedicated Channels
GSM Network Mohyee Mikhemar 2002 31
Control Channels
Common Control Channels (PCH): Paging Control Channel
Declare a coming call (RACH): Random Access Channel
Used to initiate a call Used to respond to a paging
(AGCH): Access Grant Channel Used to assign a dedicated channel for
further communication
GSM Network Mohyee Mikhemar 2002 32
Control Channels
Broadcast Channels
Common Control Channels
Dedicated Channels
GSM Network Mohyee Mikhemar 2002 33
Control Channels
Dedicated Channels (SDCCH): Stand alone dedicated control
Channel Call setup procedure SMS
(SACCH): Slow Associated control Channel () Setup power level and time advance () Inform the BS about received power level
(FACCH): Fast Associated control Channel Stolen for urgent hardover
GSM Network Mohyee Mikhemar 2002 34
Burst
It’s the information contained in one
time slot
1 time slot = 0.577 m.sec.
I frame = 8 time slots = 4.615
m.sec.
GSM Network Mohyee Mikhemar 2002 35
Mapping
Frame No
F
D0
S
D0
B
D0
B
D0
C
D1
B
D1
B
D1
C
D1
C
D2
C
D2
F
D2
S
D2
C
D3
C
D3
C
D3
C
D3
T T T T TT T T T T T T TS T T
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
f
C0
C1
C2
C3
T T T T TT T T T T T T TS T T
T T T T TT T T T T T T TS T T
T T T T TT T T T T T T TS T T
T T T T TT T T T T T T TS T T
T T T T TT T T T T T T TS T T
Frequency CorrectionSynchronization
ChannelBroadcast ChannelCommon Control
Channel
GSM Network Mohyee Mikhemar 2002 36
Mapping
Frame No
F
D0
S
D0
B
D0
B
D0
C
D1
B
D1
B
D1
C
D1
C
D2
C
D2
F
D2
S
D2
C
D3
C
D3
C
D3
C
D3
T T T T TT T T T T T T TS T T
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
f
C0
C1
C2
C3
T T T T TT T T T T T T TS T T
T T T T TT T T T T T T TS T T
T T T T TT T T T T T T TS T T
T T T T TT T T T T T T TS T T
T T T T TT T T T T T T TS T T
Stand alone Control Channel
Traffic Channel
Slow Associated Control Channel
GSM Network Mohyee Mikhemar 2002 37
Traffic Multiframe (26 Frames)
It’s repeated on C0, TS2-7 and all TS’s on all other carriers
T T T T T T T T T T T T T T T T T T T T T T T T IS
12 Traffic bursts 12 Traffic bursts
Slow Associated:• Power Control• Time Advance
Idle:• Reserved for future use
GSM Network Mohyee Mikhemar 2002 38
Control Multiframe (51 frames)
C0, TS0:
B B B B C C C C
I
10 bursts
F S F S C C C C C C CC
10 bursts
F S C C C C C C CC
10 bursts
F S C C C C C C CC
10 bursts
F S C C C C C C CC
10 bursts Idle
GSM Network Mohyee Mikhemar 2002 39
Control Multiframe (51 frames)
C0, TS1:
48 bursts
D0 I
Idle
D1 D2 D3 D4 D5 D6 D7 S4 S5 S6 S7
3 bursts
48 bursts
D0 I
Idle
D1 D2 D3 D4 D5 D6 D7 S0 S1 S2 S3
3 bursts
D:Stand alone (Call setup – SMS )
S:Slow Associated (Power Level-Time Advance)
GSM Network Mohyee Mikhemar 2002 40
TDMA Frame Structure
1 time slot = 15/26 m.sec 1 frame = 8 time slots = 120/26 m.sec. 1 traffic multiframe= 26 frame= 120 m.sec 1 Control multiframe= 51 frame= 235 m.sec 1 Super frame= 51 traffic=26 Control
= 1326 frames = 6.12 sec 1 hyperframe= 2048 superframe
= 3 hours 28 minutes 53.76 sec
GSM Network Mohyee Mikhemar 2002 41
Bust Types
Normal burst
Frequency correction burst
Synchronization burst
Access burst
GSM Network Mohyee Mikhemar 2002 42
Bust Types Normal burst
Frequency correction burst
Synchronization burst
Access burst
26 1 57 3 8.251573
TailBits
Encrypted bits
Training Sequenc
e
Flag
Guard interv
al
GSM Network Mohyee Mikhemar 2002 43
Bust Types Normal burst
Frequency correction burst
Synchronization burst
Access burst
3 8.251423
TailBits
All ZeroPattern
Guard interv
al
GSM Network Mohyee Mikhemar 2002 44
Bust Types Normal burst
Frequency correction burst
Synchronization burst
Access burst
64 39 3 8.25393
TailBits
Encrypted bits
Training Sequenc
e
Guard interv
al
GSM Network Mohyee Mikhemar 2002 45
Bust Types Normal burst
Frequency correction burst
Synchronization burst
Access burst
36 3 68.25418
TailBits
Encrypted bits
Training Sequenc
e
Guard interv
al
GSM Network Mohyee Mikhemar 2002 46
Notes C0 is called the beacon and is transmitted with
the maximum available power in the cell. There is a 3 time slots time shift between the
uplink and the downlink, this simplify the circuits and enable using one antenna and a duplexer.
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7
TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7