Training Gsm Basic[1]
Transcript of Training Gsm Basic[1]
-
7/31/2019 Training Gsm Basic[1]
1/176
1
-
7/31/2019 Training Gsm Basic[1]
2/176
2
GSM Foundation Course
Course Content Basic Telephony & Cellular
Principal of Cellular Communication
GSM Features
GSM Network ComponentsGSM Terrestrial Interfaces
Basic GSM Processes
GSM Air Interface
Radio Interface Optimization, Supplementary services &
Contemporary Networks
-
7/31/2019 Training Gsm Basic[1]
3/176
3
ESSAR Telecom
Telecom Service Provisions GSM Basic Internet
ESSAR GSM Service Provider in Punjab, Delhi,
Rajasthan, U.P (East) & Haryana Basic Service Provider in the state of Punjab.
-
7/31/2019 Training Gsm Basic[1]
4/176
4
Service Industry
Service Provider is not a Equipment
Manufacturer.
The Service Provider has a license to operate in a
geographical boundary (state/circle/ country).
It buys equipment from OEM Suppliers (Vendors).
Installs & commissions the equipment thus
making its own Network.
Provides the desired service to its subscribers.
-
7/31/2019 Training Gsm Basic[1]
5/176
ESSAR CELLPHONE
Punjab
Haryana
U.P (East)Rajasthan
Delhi
Coverage Area
-
7/31/2019 Training Gsm Basic[1]
6/176
6
ORGANISATION STRUCTURE
PROMOTERS
TECHNICALPLANNING
IMPLEMENTATION
OPERATIONS
OPERATIONS SYSTEM SUPPORT
BILLING
IT
ACTIVATIONS
MARKETING
CUSTOMER CARESALES
SUPPORT FUNCTIONS
HR, ADMIN, ACCOUNTS
-
7/31/2019 Training Gsm Basic[1]
7/1767
Basic Telephony
Off HookDial Tone
Dialing Digits
RBT
Conversation
Ring
Off Hook &Conversation
SignalingTraffic
SWITCH / EXCHANGE
-
7/31/2019 Training Gsm Basic[1]
8/1768
2 Mb E1 (PCM)
Sample Rate 8 kHz8 bits per sample 64 kbps
1
31
16
0
300 - 3400 Hz
1 st TCH
17 th TS
30 th TCH
15 th TCH
-
7/31/2019 Training Gsm Basic[1]
9/1769
Wireless Telephony
BSC
BTS BTS
Mobile Subscriber...
MSC
-
7/31/2019 Training Gsm Basic[1]
10/17610
Wireless Communication
Alternative means of wireless communication
Walkie - Talkie Pagers Trunked private radios
Mobile Phone - the magic technology that enableseveryone to communicate anywhere with anybody.
-
7/31/2019 Training Gsm Basic[1]
11/176
11
-
7/31/2019 Training Gsm Basic[1]
12/17612
Cellular Communication
A cellular system links Mobile subscribers to PublicTelephone System or to another Mobile subscribers.
It removes the fixed wiring used in a traditional
telephone installation.
Mobile subscriber is able to move around, perhaps
can travel in a vehicle or on foot & still make & receive
call.
-
7/31/2019 Training Gsm Basic[1]
13/17613
Advantage of Cellular Communication
Mobility
Flexibility
Convergence
Greater QOS Network Expansion
Revenue/Profit
-
7/31/2019 Training Gsm Basic[1]
14/176
WHAT IS CELLULAR TELEPHONY ?
CONSIDERATIONS -
FREQUENCY
SUBSCRIBERDENSITY
COVERAGE
Base Station
Base Station
Base Station
Base StationBase Station
Base Station
-
7/31/2019 Training Gsm Basic[1]
15/17615
The Cell
Cellular Radio involves dividing a large service area
into regions called cells.
Each cell has the equipment to switch, transmit and
receive calls.
Cells - Reduce the need of High powered transmission
Cells - Conventionally regarded as being hexagonal,
but in reality they are irregularly shaped.
Cell shape is determined by the nature of the
surrounding area e.g. Hills , tall building etc.
-
7/31/2019 Training Gsm Basic[1]
16/176
The CELL
What is a cell ?
A cell is a certain areathat can be reachedwith one transceiver
or A small collection oftransceivers ondifferent channels at asingle base site.
The hexagonal-shaped communication cells areartificial & are generated to simplify the planning &design of a cellular network.
BTS
-
7/31/2019 Training Gsm Basic[1]
17/17617
Coverage & Capacity
Coverage Percentage of the geographical area covered
by cellular service where mobile telephony isavailable
Capacity - Number of calls that can be handled in a
certain area within a certain period of time.
Capacity can also refer to the probability thatusers will be denied access to a system due tothe simple unavailability of radio channels.
-
7/31/2019 Training Gsm Basic[1]
18/17618
Cells
-
7/31/2019 Training Gsm Basic[1]
19/17619
Cell Size
Large Cells
35 Km
Remote Areas
High TransmissionPower
Few subscribers
Small Cells
Near about 1 KM
Urban Areas
Low TransmissionPower
Many Subscribers
-
7/31/2019 Training Gsm Basic[1]
20/17620
MICRO CELL
Below Rooftop ~ Railway Platforms, Airports,~ Busy Shopping Bazaar etc.
Low Tx Power~ 1 Watt max.
Limited Coverage~ 200m - 500m
Hotspot Solution
Special Algorithms for HO
-
7/31/2019 Training Gsm Basic[1]
21/17621
PICO CELLS
Pico Cell
Inside offices, Buildings
Very Low Tx Power~ Less than 1 Watt
Limited Coverage~ 50 -100m
Capacity Solution
Special Algorithms for HO
-
7/31/2019 Training Gsm Basic[1]
22/17622
Analog Mobile Telephony
End of 1980s Analog Systems unable tomeet continuing demands
Severely confined spectrum allocations
Interference in multipath fading environment
Incompatibility among various analog systems
Inability to substantially reduce the cost ofmobile terminals and infrastructure required
-
7/31/2019 Training Gsm Basic[1]
23/17623
Digital Mobile Telephony
Spectrum space - most limited and preciousresource
Solution - further multiplex traffic (time
domain)
Can be realized with Digital Techniques only.
-
7/31/2019 Training Gsm Basic[1]
24/17624
Different Standards Worldwide
Till 1982 Cellular Systems were exclusivelyAnalog Radio Technology.
Advanced Mobile Phone Service (AMPS)
U.S. standard on the 800 MHz Band
Total Access Communication System (TACS)
U.K. standard on 900 MHz band
Nordic Mobile Telephone System (NMT)
Scandinavian standard on the 450 & 900 MHzband
-
7/31/2019 Training Gsm Basic[1]
25/17625
GSM History and Organization
1979 Europe wide frequency band reserved for
Cellular 1982 Groupe Speciale Mobile created within
CEPT
1986 GSM had full time in Paris
1988 ETSI takes over GSM Committee
1990 The phase 1 GSM Recommendationsfrozen
1991 GSM Committee renamed Special MobileGroup and GSM renamed as GlobalSystem for Mobile Communication
1992 GSM is launched for commercial
operations
-
7/31/2019 Training Gsm Basic[1]
26/176
26
GSM - IN CELLULAR TELEPHONY
Each Cell in the Cellular Network consists of oneor more RF carriers.
An RF carrier is a pair of radio frequencies One used in upward direction by MS - Uplink Other used in downward direction by BTS -
Downlink The transmit and receive frequencies are
separated by a gap of 45 MHz in GSM of 75MHz in DCS.
There are 124 carries in GSM Band. With eachcarrier carrying 7 timeslots, only 124 x 7 = 868calls can be made!
Frequency Reuse is the solution
-
7/31/2019 Training Gsm Basic[1]
27/176
27
Uplink-Downlink
Downlink = 935 to 960 MHz
Uplink = 890 to 915 MHz
BTS Tx MS Rx
BTS Rx MS Tx
dl
ul
-
7/31/2019 Training Gsm Basic[1]
28/176
28
Frequency & ARFCN
Ful(n) = 890.0 + (0.2) *n MHz
Fdl(n) = F ul + 45 MHz
where n =ARFCN ; 1 n 124
-
7/31/2019 Training Gsm Basic[1]
29/176
29
0 7
3
0
5
0 1
2
0 7
3
0
5
0 1 2
TDMA & FDMA
F D M A
200KHz
Uplink - MS Tx890MHz to 915MHz
Downlink - BTS Tx935MHz to 960MHz
-
7/31/2019 Training Gsm Basic[1]
30/176
30
GSM Burst & TDMA Frame
0 1 2 3 4 5 6 7 2 4 5 6 730 1
FRAME 1 FRAME 2
Training sequence Information Information
GUARD PERIOD GUARD PERIOD
TAIL BITS TAIL BITS
-
7/31/2019 Training Gsm Basic[1]
31/176
31
Frequency Reuse Pattern
Three types of frequency reuse patterns
7 Cell reuse pattern
4 cell reuse pattern
3 cell reuse pattern
-
7/31/2019 Training Gsm Basic[1]
32/176
32
Cell Dia = R
FREQUENCY RE - USE
Frequency Re-use
7/21 cell cluster
1
23
45
6
7
Two re-use distances
D D/R = (3N) 1/2
where N is Cluster size
-
7/31/2019 Training Gsm Basic[1]
33/176
33
Principal Of Sectorization
Omni Directional Cells
120 degree Sectors 60 Degree sectors
Each Sector in a Site has its own allocation ofRadio Carriers.
Advantage
By frequent reuse of frequency morecapacity can be achieved .
-
7/31/2019 Training Gsm Basic[1]
34/176
34
a1 a2
a3 a3
a4a6
a5
Cell Sectorisation
OMNI CELL
1 ANTENNA
b1
b2
b3
120 O CELLS
3 ANTENNAS
60 O CELLS
6 ANTENNAS
-
7/31/2019 Training Gsm Basic[1]
35/176
35
3 Site Reuse Pattern
c2
c1c3
a1
a2
a3
b1
b2
b3
c1c2
c3Cell Re-use
-
7/31/2019 Training Gsm Basic[1]
36/176
36
Cellular 1Planning Steps
Cellular Topology Cell splitting & Cell Repeat Patterns
3 cluster site 3/9 cell cluster 4 cluster site 4/12 cell cluster
Sites in the middle
-
7/31/2019 Training Gsm Basic[1]
37/176
37
GSM Antennas
Directional Antennas Vertically Polarized.
Collinear Dipole Array with
8 to 12 elements. Beam Width 45 o, 60 o, 90 o.
High Gain Antennas with
gain of 16 to 18 dbi. Mechanically/Electrically
Downtiltable.
-
7/31/2019 Training Gsm Basic[1]
38/176
38
-
7/31/2019 Training Gsm Basic[1]
39/176
39
Features of GSM
Compatibility
Noise Robust
Increased Capacity & Flexibility
Use of Standard Open Interfaces
Improved Security & Confidentiality
Cleaner Handovers
Subscriber Identification
ISDN Compatibility
Enhanced Range of Services
-
7/31/2019 Training Gsm Basic[1]
40/176
40
Compatibility
With rapid Developments
there was a need for acommon Standard forMobile Communication.
With GSM, one coulddrive from Germany toSpain without a CallDrop.
Due to versatility of GSM,it was adopted by manycountries, even outsideEurope.
-
7/31/2019 Training Gsm Basic[1]
41/176
41
Noise Robust
To combat the problems
due to Noise-Digital Interface is used .
Digital Interface
Protect these errorsusing Error Detection &Correction Techniques.
Immune to higher levels
of noise and interference Improvements in Quality
as well as Efficiency-Robust Air Interface.
-
7/31/2019 Training Gsm Basic[1]
42/176
42
Increased Capacity and Flexibility
Analogue Air Interface
Every connection requires aseparate RF carrier and thusRF hardware.
System Expansion Time Consuming
Costly & Labor Intensive.
Intricate RF Planning.
Digital Interface
8 simultaneous conversationson one RF carrier.
-
7/31/2019 Training Gsm Basic[1]
43/176
43
Standardized Open Interfaces
Low Price
Uses standard interfaces like C7, X.25 etc.
Versatility to choose equipment from different
manufacturer thereby reducing the pricingmonopoly.
Flexibility
Great flexibility in situating Networkcomponents because of Standard Interfaces.
Efficient use of terrestrial links.
f
-
7/31/2019 Training Gsm Basic[1]
44/176
44
Better Security & Confidentiality
High Security risk for
Analogue System operators.
GSM
No Eavesdropping
High speech and data
confidentiality.
Digitized, Encoded and
Encrypted (A8 algorithm)
Subscriber Authentication
(A3 algorithm)
l d
-
7/31/2019 Training Gsm Basic[1]
45/176
45
Cleaner Handovers
The mobile measures up to 32 adjacent cells for
Signal Strength (RxLevel)
Signal Quality (RxQual)
updated every 480 mS and sends to BTS
Sophisticated Handover based on
RxLevel
Interference
RxQual
Timing Advance
Power Budget
d
-
7/31/2019 Training Gsm Basic[1]
46/176
46
Base Station 2
Base Station 3
Base Station 1
Handovers
ISDN C ibili
-
7/31/2019 Training Gsm Basic[1]
47/176
47
ISDN Compatibility
ISDN (Integrated Services Digital Network)
Advanced Telecom Network designed to carry
voice and user data over the standard
telephones lines. 2B+D Signalling and information on ISDN line.
The GSM Network is designed to operate within
the ISDN System.
GSM provides features compatible with ISDN.
-
7/31/2019 Training Gsm Basic[1]
48/176
48
-
7/31/2019 Training Gsm Basic[1]
49/176
49
GSM NETWORK ELEMENTS
-
7/31/2019 Training Gsm Basic[1]
50/176
50
GSM NETWORK ELEMENTS
PSTNEC
MSC
HLR
AUCVLR
EIRIWF
TRAU BSC
BTS
Network Switching System
BSS
SIM
ME
MS
GSM N t k C t
-
7/31/2019 Training Gsm Basic[1]
51/176
51
GSM Network Components
Mobile Station consists of two parts- Mobile Equipment (ME)
Subscriber Identity Module (SIM)
ME Hardware e.g. Telephone, Fax Machine,
Computer.
SIM
Smart Card which plugs into the ME. NETCOMP
M bil E i t (ME)
-
7/31/2019 Training Gsm Basic[1]
52/176
52
Mobile Equipment (ME)
ME are of three types- Vehicle Mounted
Portable Mobile Unit Handportable Unit
MEs have distinct features -Classmarks sent in
initial message to Network.
NETCOMP
ME (Cl k I f ti )
-
7/31/2019 Training Gsm Basic[1]
53/176
53
ME (Classmark Information)
Revision Level
Phase of the GSM specs ME comply with.
RF Power Capability
Max power ME is able to Transmit. Ciphering Algorithm Used
Presently A5
Phase 2 specifies Algorithms A5/0 to A5/7.
Frequency Capability
SMS Capability NETCOMP
M bil E i t
-
7/31/2019 Training Gsm Basic[1]
54/176
54
TypicalSettings
Mobile Equipment
Class Power O/p
1 20 W
2 8 W
3 5 W
4 2 W
5 0.8 W
NETCOMP
SIM
-
7/31/2019 Training Gsm Basic[1]
55/176
55
SIM
Subscriber Interface IdentityModule
The SIM stores
Subscriber Parameters
Personal Data for identifying
Subscriber to the Network.
IMSI,, MSISDN, PIN, PUK, Ki,A3, A8 (for Kc generation)
Space reserved for TMSI &
LAI
--------------
--------------
Small SIM
Full Size SIM Card
----------------------------
NETCOMP
SIM Internal Structure
-
7/31/2019 Training Gsm Basic[1]
56/176
56
SIM - Internal Structure
CPU
EEPROM
RAM
ROM
I/O8
User Data 16 kB
Basic Operating Syste16 to 24 kB
Working Area for CP256 to 512 bytes
NETCOMP
SIM(IMSI)
-
7/31/2019 Training Gsm Basic[1]
57/176
57
SIM(IMSI)
IMSI(International Mobile Subscriber Identity)
Transmitted over Air Interface on initialization
Permanently stored on SIM card
15 digit Decimal
MCC (3) MNC (2) MSIC (10)
NETCOMP
SIM (LAI)
-
7/31/2019 Training Gsm Basic[1]
58/176
58
LAI (Location Area Identity)
MCC 3 digit number (BCD), two Octets ( A & B)
MNC 2 digit number (BCD), one Octet LAC 3 digit number (Binary) , two Octets
0-65535
CI 5 digit number (Binary) , two Octets0-65535
SIM (LAI)
LACMCC MNC CI
NETCOMP
SIM
-
7/31/2019 Training Gsm Basic[1]
59/176
59
SIM
MSISDN
10 digit number to which a subscriber is beingcalled.
PIN (Personal Identification Number) Four digit PIN An internal security to Protect the SIM from
illegal use. Card blocks itself after three wrong entries
PUK (Personal Unblocking Key) 8 digit code to unblock the SIM Card
Ki (Authentication Key), A3 & A8 AlgorithmsNETCOMP
SIM (TMSI)
-
7/31/2019 Training Gsm Basic[1]
60/176
60
SIM (TMSI)
Temporary Mobile Subscriber Identity
Periodically changed by the SystemManagement on instances like location updateetc.
Reason for use of TMSI
To prevent a possible intruder from identifyingGSM users, TMSI is used
Management
Assignment, Administration & Updating isperformed by VLR.
NETCOMP
Transcoder
-
7/31/2019 Training Gsm Basic[1]
61/176
61
Transcoder
Converts 64 Kbps PCM circuits from MSC to 16
Kbps BSS circuits.
Each 30 channel 2 Mbps PCM link can carry 120GSM - specified voice channels.
NETCOMP
Transcoder
-
7/31/2019 Training Gsm Basic[1]
62/176
62
Transcoder
MSC BSS
XCDR120 GSM TCH
1 2 3 4
Transcoder Information from FOUR calls (4x16 KBPS put into ONE 64 KBPS timeslot
30 Channel PCM1234
NETCOMP
-
7/31/2019 Training Gsm Basic[1]
63/176
63
Base Station System (BSS)
-
7/31/2019 Training Gsm Basic[1]
64/176
64
Base Station System (BSS)
BSS (Base Station System) BSC (Base Site Controller) BTS (Base Transceiver Station)
XCDR (Transcoder)
NetworkSwitchingSystem(NSS)
XCDR
BSC
BTSNETCOMP
BTS
Base Station System (BSS)
-
7/31/2019 Training Gsm Basic[1]
65/176
65
Base Station System (BSS)
BSC
Controls upto 40 BTS Conveys information to/from BTS Connects terrestrial circuits & Air Interface
Channels Controls handovers between BTSs under itself
BTS Contains RF Hardware Limited control functionality 1 - 6 carriers in a BTS Cabinet 7 - 48 simultaneous calls per BTS
NETCOMP
BTS
A BTS Cabinet
-
7/31/2019 Training Gsm Basic[1]
66/176
66
A BTS Cabinet
OUTER VIEW INNER VIEW NETCOMP
BSS Configuration
-
7/31/2019 Training Gsm Basic[1]
67/176
67
BSS Configuration
Collocated BTS
Remote BTS
Daisy Chain BTS
Star Configuration
Loop Configuration
NETCOMP
BTS
Daisy Chain Configuration
-
7/31/2019 Training Gsm Basic[1]
68/176
68
Daisy Chain Configuration
BSC
BTS
BTS
BTS NETCOMP
A l l B T
S on1 E 1
Star Configuration
-
7/31/2019 Training Gsm Basic[1]
69/176
69
Star Configuration
BSC
BTS
BTS BTS
BTS
NETCOMP
Loop Configuration
-
7/31/2019 Training Gsm Basic[1]
70/176
70
Loop Configuration
BSC
BTS
BTS BTS
BTS
Loop Configuration
NETCOMP
Network Switching System(NSS)
-
7/31/2019 Training Gsm Basic[1]
71/176
71
Network Switching System(NSS)
NSS (Network Switching System)
MSC (Mobile Switching Centre)
HLR (Home Location Register)
VLR (Visitor Location Register)
EIR (Equipment Identity Register)
AUC (Authentication Centre)
IWF (Interworking Function) EC (Echo Canceller)
NETCOMP
MSC
MOBILE SWITCHING CENTRE
-
7/31/2019 Training Gsm Basic[1]
72/176
72
MOBILE SWITCHING CENTRE
NETCOMP
GSM Network Component
-
7/31/2019 Training Gsm Basic[1]
73/176
73
GSM Network Component
MSC
Call Switching
Operation & Management Support
Internetwork Interworking
Collects call billing data
Gateway MSC
MSC which provides interface between PSTN &BSSs in the GSM Network.
NETCOMP
Home Location Register (HLR)
-
7/31/2019 Training Gsm Basic[1]
74/176
74
Home Location Register (HLR)
Reference database for the Subscriber profiles -
Subscriber ID (IMSI & MSISDN)
Current VLR Address
Supplementary Services subscribed
Supplementary Service Information
Subscriber Status (Registered/deregistered)
Authentication Key and AUC functionality
TMSI
MSRNNETCOMP
Visitor Location Register (VLR)
-
7/31/2019 Training Gsm Basic[1]
75/176
75
Visitor Location Register (VLR)
Temporary Data , which exists as long as the
subscriber is active in a particular Coverage area. Contains the following-
Mobile Status (Busy/ Free/ No Answer/etc.)
Location Area Identity (LAI) TMSI
MSRN (Mobile Station Roaming Number)
NETCOMP
Equipment Identity Register (EIR)
-
7/31/2019 Training Gsm Basic[1]
76/176
76
qu p e t de t ty eg ste ( )
Contains Database for validating IMEI
White List (valid ME)
Black List (Stolen ME)
Grey List (Faulty ME)
NETCOMP
Inter Working Function
-
7/31/2019 Training Gsm Basic[1]
77/176
77
Provides function to enable the GSM
System to interface with Public/PrivateData Networks.
The basic feature of the IWF are Rate Conversion Protocol adaptation
IWF incorporates Modem Bank.e.g. GSM DTE PSTN DTE
IWF Analogue Modem
g
NETCOMP
Echo Canceller
-
7/31/2019 Training Gsm Basic[1]
78/176
78
Echo is apparent only in Mobile - Land
conversation & is generated at the 2 wire to 4 wireinterface.
To avoid it, Echo Canceller (EC) is used.
Echo is irritating to MS Subscriber Total Round Trip delay of 180 ms in the GSM
system
EC is placed on the PSTN side of the Switch Cancellation up to 68 ms with EC
NETCOMP
Operation & Maintenance Centre
-
7/31/2019 Training Gsm Basic[1]
79/176
79
p
Event & Alarm Management
Fault Management
Performance Management Configuration Management
Security Management
Operation & Maintenance Centre
-
7/31/2019 Training Gsm Basic[1]
80/176
o The OMC has access to the (G)MSC, BSC.o Handles error messages being reported from the
Networko Controls the traffic load of the BSC, and the BTS.
p
NETWORK MANAGEMENT CENTRE
-
7/31/2019 Training Gsm Basic[1]
81/176
o NETWORK MANAGEMENT CENTRE (NMC) Offers Hierarchical Regionalised Network
Management of a complete GSM system.
Functionality of the NMC Monitors Nodes on the Network
Monitors Network Element Statistics
Monitors OMC regions & provides
information to OMC staff Enables Long Term Planning for
entire Network
MMI RAM>MMI RAM>MMI RAM>
NETWORK MANAGEMENT CENTRE
-
7/31/2019 Training Gsm Basic[1]
82/176
NMC
OMC OMC
OMC
REGION 2 REGION 3
REGION 1
NETWORK
GSM Terrestrial Interfaces
-
7/31/2019 Training Gsm Basic[1]
83/176
83
Broadly classified into two types of interfaces-
Standard Interfaces
2 Mbps Trunks (E1)
Signalling System No. 7 SS7 ( CCS7)
X.25 (Packet Switched Mode)
GSM Interfaces
GSM Interfaces
-
7/31/2019 Training Gsm Basic[1]
84/176
84
Um MS - BTS Abis BTS - BSC
A BSC - MSC
B MSC - VLR
C MSC - HLR
D VLR - HLR
E MSC - MSC
F MSC - EIR
G VLR - VLR
H HLR - AUC
-
7/31/2019 Training Gsm Basic[1]
85/176
85
-
7/31/2019 Training Gsm Basic[1]
86/176
86
Basic Processes
-
7/31/2019 Training Gsm Basic[1]
87/176
87
AUTHENTICATION
CIPHERING
REGISTRATION
CALL ESTABLISHMENT
HANDOVER / HANDOFF
ROAMING
AUTHENTICATION ALGORITHM
-
7/31/2019 Training Gsm Basic[1]
88/176
88
NSS
MS
HLR
AUC
AUTH.ALGORITHMS
A3
SIM
MS
AUTH.ALGORITHMS
A3
Ki
RAND
RAND
COMPARE
SRES
SRES
Ki
AIR INTERFACE
Ciphering
-
7/31/2019 Training Gsm Basic[1]
89/176
89
Data protection is required on air interface.
A5 algorithm is used. A specific key called Ciphering Key (Kc) , is
generated from RAND and A8 algorithm . A8 is on the SIM.
A8
RANDKi
Kc
Ciphering
-
7/31/2019 Training Gsm Basic[1]
90/176
90
A5Data
Kc
Ciphered
Data A5
Kc
Data
ROAMING
-
7/31/2019 Training Gsm Basic[1]
91/176
MSC
ME
ME
PSTN
MSC
VLR
HLR
INDIA
UK
ROAMING
-
7/31/2019 Training Gsm Basic[1]
92/176
o The mobile roams to another country (UK) and requests a
Location Update when switched ON.o The VLR (UK) informs the home HLR (India) of the mobiles
new location (UK).
o The HLR updates its location information and sends the
subscriber information to the VLR (UK). o The HLR requests the subscriber information be removed
from the VLR (India).
o The VLR (India) acknowledges, and removes the subscriber
information from its database.
o After the mobiles registration is completed in UKs
MSC/VLR, the mobile is able to use network services (MOC,
MTC etc.)
Transmission Media
-
7/31/2019 Training Gsm Basic[1]
93/176
93
Access Network
Microwave 15 /23 GHz
Backbone Network
Microwave 7 GHz
Optical Fibers
Leased Line( From Dot or any other
service provider on any media)
Access Microwave ( 15 GHz)
-
7/31/2019 Training Gsm Basic[1]
94/176
94
14.250 to 14.500 MHz and14.400 to 15.350 MHz
4 QAM & 16 QAM Modulation
Split Mount Version with Hot
Standby Facility Bandwidth ranging from 1.25
MHz to 28 MHz dependingupon Data Rate andModulation type
4 E1 Radio with 3 spotfrequencies in our case
Backbone Microwave (7 GHz)
-
7/31/2019 Training Gsm Basic[1]
95/176
95
7.125 to 7.850 MHz and 7.725
to 8.500 MHz 4 QAM & 16 QAM Modulation
Split Mount Version with hot
standby facility Bandwidth ranging from 1.25
MHz to 28 MHz dependingupon Data Rate and
Modulation type 16 E1 Radio with 1 spot
frequencies in our case
Optical Fiber
-
7/31/2019 Training Gsm Basic[1]
96/176
96
Low Losses 0.5 dB/km & High Data Rates
Types of Fiber Step Index Graded Index
# Graded Index are better.Modes of Light in fiber
Mono Mode
Multi Mode# Mono Mode has less losses than Multi
Mode.
Optical Fiber
-
7/31/2019 Training Gsm Basic[1]
97/176
97
Different Possible Combinations Mono Mode Step Index 10 / 125 m
Mono Mode Graded index
Multi Mode Step Index 100 / 300 m
Multi Mode Graded Index 75 / 130 m Mono Mode Graded Index would have beenthe best but fabrication not possible
140 Mbps OLTE , Mono Mode Step Index in our case
-
7/31/2019 Training Gsm Basic[1]
98/176
98
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
99/176
99
Physical Channel
Logical Channel
Physical Channel
Physical channel is the medium over which theinformation is carried.
Logical Channel
Logical channels consists of the informationcarried over the Physical Channel.
TDMA & FDMA
-
7/31/2019 Training Gsm Basic[1]
100/176
100
0 7
3
0
5
0 1
2
0 7
3
0
5
0 1 2
F D M A 200KHz
Uplink - MS Tx 890MHz to 915MHz
Downlink - BTS Tx935MHz to 960MHz
LOGICAL CHANNELS
-
7/31/2019 Training Gsm Basic[1]
101/176
101
0 1 2 3 4 5 6 7
3
57encrypted
57encrypted
26training
1S
1S
3T
8.25GP
3T
577 S
577 S x 8 = 4.615mS
TDMA Frame
Normal Burst
26 Frame Multi-frame
BURST
-
7/31/2019 Training Gsm Basic[1]
102/176
102
Time is divided into discrete periods
called Timeslots
The Time Slots are arranged in a sequence, conventionally numbered 0 to 7.
Each repetition of this sequence is calleda TDMA Frame.
The information content carried in onetime slot is called a burst.
BURST
-
7/31/2019 Training Gsm Basic[1]
103/176
103
Information
Main Area where the Speech, Data or Control infois held Guard Period
To enable the burst to hit the time slot (0.031ms)
Stealing Flags 2 bits are set when TCH is to stolen by a FACCH
Training Sequence For estimation of transfer characteristics of
physical media Tail Bits
Used to indicate beginning and end of the burst.
Five Types of Burst
-
7/31/2019 Training Gsm Basic[1]
104/176
104
Normal Burst
Traffic & Control Channels Bi-directional Frequency Correction Burst
FCCH Downlink
Synchronization Burst SCH Downlink
Dummy Burst
BCCH Carrier Downlink Access Burst
RACH Uplink
GSM Logical Channels
-
7/31/2019 Training Gsm Basic[1]
105/176
105
TCH SACCH
FACCH
Control Channels BCCH
CCCH
ACCH
DCCH
LOGICAL CHANNELS
-
7/31/2019 Training Gsm Basic[1]
106/176
106
TDMA Frame
26 Frame Multi-frame
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
Frames & Multiframes
-
7/31/2019 Training Gsm Basic[1]
107/176
107
Several Logical channels share one time slot.
Individual channels are sequenced, & each
channel gets the time it requires.
Sequence is carried out using Multiframes. Traffic Channel occupy a 26-frame multiframe
(120 ms )
Control Channel occupy a 51-frame multiframe
(235 ms).
Traffic Channels - TCH
-
7/31/2019 Training Gsm Basic[1]
108/176
108
TCH
TCH
TCH / FS 9.6
DATA
TCH / HS
4.8
2.4
FACCHSAACH
BCCH Channel
-
7/31/2019 Training Gsm Basic[1]
109/176
109
CCH
BCCH
BCCHSynchronizing Channels
FCH SCH
Broadcast ControlChannel - Downlink only
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
110/176
110
BCCH Transmitted at all times & conveys information
about Cell Timing and Configuration
BCCH, FCCH, SCH
CCCH Used by BSS & MS when trying to initiate a
connection over the air
RACH, PCH, AGCH, CBCH
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
111/176
111
DCCH Used to convey signaling information during
call setup
SDCCH
ACCH Used to transmit signaling information when a
call is in progress
FACCH & SACCH
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
112/176
112
ACCH SAACH
Conveys Power Control & TimingInformation in the downlink direction.
RSSI and Quality reports in the uplinkdirection.
FACCH
To carry out user authentication andhandovers. It steals the TCH burst andinserts its own information.
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
113/176
113
Acronyms
BCCH Broadcast Control Channel
CCCH Common Control Channel
DCCH Dedicated Control Channel
ACCH Associated Control Channel
SDCCH Standalone Dedicated Control Channel
RACH Random Access Channel
PCH Paging Channel
AGCH Access Grant Channel
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
114/176
114
BCCH Location Area Identity List of neighbouring cells, to be monitored
List of frequencies used in the cell
Cell Identity Power Control Indicator
DTX permitted
Access Control (e.g emergency calls, callbarring)
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
115/176
115
Always transmitted at constant power at all
times Dummy burst are sent to ensure continuity
when no traffic information is sent.
FCCH Mobile corrects the frequency of its internal
time base by reading this logical channel.
Easily detected by the mobile.
After FCCH, mobile is able to detect SCHwhich contains timing information.
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
116/176
116
SCH Carries the information for mobile to
synchronize to the TDMA frame structure &know the timing of the individual timeslots.
Frame Number & BSIC (Base Station IdentityCode)
CCCH
RACH Transmitted by the Mobile when it wishes to
gain access to the system
Channels On Air Interface
-
7/31/2019 Training Gsm Basic[1]
117/176
117
PCH
Transmitted by the BTS when it wishes tocontact a specific mobile.
AGCH
Transmitted by the BTS to assign dedicatedresources to an MS such as SDCCH
CBCH
To transmit messages to all mobiles withina cell. CBCH will steal some time of anSDCCH to do this.
Channel Combinations
-
7/31/2019 Training Gsm Basic[1]
118/176
118
Full rate Traffic Channel Combination
TCH8/FACCH + SACCH
Broadcast Channel Combination
BCCH + CCCH
Dedicated Channel Combination
SDCCH8 + SACCH8
Combined Channel Combination BCCH + CCCH + SDCCH4 + SACCH4
Channel Combinations (Timeslots)
-
7/31/2019 Training Gsm Basic[1]
119/176
119
Traffic Channel Combination
TCH8/FACCH +SACCH Can be on any Time slot
Broadcast Channel Combination BCCH +CCCH
Can be on Timeslot 0, 2, 4, 6
Dedicated Channel Combination SDCCH8 + SACCH8 Any Time slot
Combined Channel Combination BCCH + CCCH +SDCCH4 + SACCH4 Can only be on 0 Timeslot
TCH Multiframe
-
7/31/2019 Training Gsm Basic[1]
120/176
120
0 5 10
SACCH
15 20
IDLE
Downlink & Uplink SACCH
BCCH/CCCH Multiframe
-
7/31/2019 Training Gsm Basic[1]
121/176
121
BCCH/CCCH
In Downlink direction the timeslot (physicalchannel) is shared by a different logicalchannels.
In the Uplink direction all timeslots areallocated to RACH.
BCCH/CCCH Multiframe
-
7/31/2019 Training Gsm Basic[1]
122/176
122
10 20 30 40 50
Downlink to MS
Uplink from MS
0 10 20 30 40 50
F S F S F S F S S I FCCCH8 TS
CCCH4 TS
BCCH CCCH8 TS
CCCH8 TS
CCCH8 TS
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 RR R R R RR R R R R R R R RR R R RR R R RRR
0
Combined Multiframe
-
7/31/2019 Training Gsm Basic[1]
123/176
123
BCCH and SDCCH share a common timeslot
Less No. of subscribers support (as only 4SDCCH)
102 frame structure
Superframes And Hyperframes
1326 TDMA frames (26*51) make asuperframe
2048 superframes make one hyperframe,after which ciphering and frequency
hopping algorithm are restarted.
Combined Multiframe
-
7/31/2019 Training Gsm Basic[1]
124/176
124
0 10 20 30 40 50
F
F
S
S
BCCH F
F
S
S F S F S
S
S A2
A0 A1
A3
I
I
F
FCCCH8 TS
F S F SCCCH8 TS
CCCH
4 TS
CCCH
4 TS
BCCH D2
D2 D3
D3
D0 D1
D0 D1
0 10 20 30 40
D3 R
R
R
R A2 A3D3
A0 A1 R
R
R
R D2
D2 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
R
R
R
R
R
R
R
D0 D1
D1D0
50
Downlink to MS
Uplink from MS
SDCCH Multiframe
-
7/31/2019 Training Gsm Basic[1]
125/176
125
0 10 20 30 40 50
I
I
Downlink to MS
Uplink from MS
I
I
I
I
D0 D1 D2 D3 D4 D5 D6 D7 A0 A1 A2 A3
D0 D1 D2 D3 D4 D5 D6 D7 A4 A5 A6 A7
0 10 20 30 40 50
I
I
I
I
I
I
D0 D1 D2 D3 D4 D5 D6 D7 A1 A2 A3 A0
D0 D1 D2 D3 D4 D5 D6 D7 A5 A6 A7 A4
Voice Coding
-
7/31/2019 Training Gsm Basic[1]
126/176
126
Block - 1 : 1, 5, 9 .. Samples
Block - 2 : 2, 6, 10, Samples
& so on for Block - 3 & Block - 4.
LPC
RPE
D i vi d
e d i n t o4 B l o
ck
s
of 4
0 S am pl e
s e a ch
LTP
Class Ia Class Ib Class II
50 bits 132 bits 78 bits
20 mS Sample Rate 8 kHz
13 bits per Sample 160 Samples
2080 bits
104 kbps
Reduction in Data Speech Encoder selects Blockwith Most Energy
Channel Coding
-
7/31/2019 Training Gsm Basic[1]
127/176
127
Error Protection And Detection
To protect the logical channel fromtransmission errors by the radio path, differentcoding schemes are used.
Coding & Interleaving Schemes dependent uponlogical channel to be encoded.
3 Coding Protection schemes Speech Channel Encoding
Control Channel Encoding Data Channel Encoding
Speech Channel Coding
-
7/31/2019 Training Gsm Basic[1]
128/176
128
Speech Information of 20 ms block is divided
over 8 GSM burst.
260 bits are grouped in three classes depending
upon the intelligible part of speech
After encoding 456 bits block is interleaved
Speech Channel Coding
-
7/31/2019 Training Gsm Basic[1]
129/176
129
ParityCheck
456 bits
Class 1b132 bits
Class 1a50 bits
Class 278 bits
50 1323 4
Convolutional Code
378 78
Tail Bits
378 78
Convolutional Coding
Control Channel Encoding
-
7/31/2019 Training Gsm Basic[1]
130/176
130
Control Channel Encoding
Block of 184 bits received by BTS Bits are protected by Cyclic Codes of Class
Fire Codes Adds 40 Parity Bits
4 Tail Bits are added Convolution Coding is done
O/p from 184 Signalling bits is 456 bits.
Control Channel Coding
-
7/31/2019 Training Gsm Basic[1]
131/176
131
184
Coding
184 40Parity Bits
Convolutional Coding
456
456 bits
4TB
Data Channel Coding
-
7/31/2019 Training Gsm Basic[1]
132/176
132
240
184
Convolutional Coding
488
4
Punctuate
456
Interleaving
-
7/31/2019 Training Gsm Basic[1]
133/176
133
Responsible for Robustness of the GSM air
interface 10 -20 % burst destroyed or corrupted on the air
interface.
Spreads the content of one information block
across several TDMA timeslots. Two types of Interleaving -
Diagonal Interleaving
Rectangular Interleaving
DIAGONAL INTERLEAVINGSPEECH
-
7/31/2019 Training Gsm Basic[1]
134/176
134
Speech Blocks
456 bits
EIGHT blocks of 57 bits,
Sent on 8 ALTERNATE timeslots
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
456 bits
RECTANGULAR INTERLEAVINGCONTROL CHANNEL
-
7/31/2019 Training Gsm Basic[1]
135/176
135
Data Blocks
456 bits
114Bits
Odd
114
BitsOdd
114
BitsEven
114
BitsEven
FOUR blocks of 114 bits,Sent on 4 timeslots
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
Interleaving
-
7/31/2019 Training Gsm Basic[1]
136/176
136
Interleaving Depths
Speech - 8 blocks Control - 4 blocks Data - 22 blocks
Speech & Data blocks are diagonally interleaved
Control block is rectagularly interleaved
Interleaving
-
7/31/2019 Training Gsm Basic[1]
137/176
137
TRAU Frame Type
Data
Control
Speech
Number of GSMBurst Spread Over
22
4
8
TRAU = Transcoder Rate Adaption Unit
-
7/31/2019 Training Gsm Basic[1]
138/176
138
-
7/31/2019 Training Gsm Basic[1]
139/176
139
MOBILE TO LAND
-
7/31/2019 Training Gsm Basic[1]
140/176
140
MSC
BSC
BTS
PSTN
Multiple Point of Interconnect
-
7/31/2019 Training Gsm Basic[1]
141/176
141
BSS TRAFIC POI TRAFIC
CITY A
CITY B
Call Scenarios
-
7/31/2019 Training Gsm Basic[1]
142/176
142
Mobile to Mobile
Intra-city Inter-city
Mobile to Land
Intra-city Inter-city
Land to Mobile
Intra-city
Inter-city
Mobile To Land Sequence
-
7/31/2019 Training Gsm Basic[1]
143/176
143
1
3
CHANNEL REQUEST
DCCH ASSIGN
SIGNALLING LINKESTABLISHED
REQUEST FOR SERVICE
SET CIPHER MODE
SET-UP
EQUIPMENT IDREQUEST
AUTHENTICATION
MS BSS MSC VLR HLR PSTN EIRRACH
AGCH
SDCCH
SDCCH
Call Info 7
4
6
5
2CR
CC
8 COMPLELTE CALL
CALL PROCEEDINGSDCCH
SDCCH ( i it)
MS BSS MSC VLR HLR PSTN EIR
-
7/31/2019 Training Gsm Basic[1]
144/176
144
9 ASSIGNMENT COMMAND
INITIAL & FINAL ADDRESS(IFAM)
ASSIGNMENT COMPLETE(ACM)
10
ANSWER(ANS)
11
CONNECT ACKNOWLEDGE
SDCCH
ASSIGNMENT COMPLELTE
MS HEARS RINGTONEFROM LAND PHONE
ALTERING
RING TONESTOPS
CONNECT
(channel)
(TCH)
FACCH
FACCH
FACCH
TCH
(circuit)
FAACH
BILLING STARTS
Hello!
Land to Mobile SequenceInitial & Final Address Msg.
(IFAM) MSISDN
MS BSS MSC VLR HLR GMSC PST
-
7/31/2019 Training Gsm Basic[1]
145/176
145
(IFAM)
Send Routing Information
Routing Information Ack
INITIAL & FINAL ADDRESS(IFAM)
Send Info for I/c Call Setup
Channel Request
Signalling Link Established
MSISDN
Paging Request
PAGE
DCCH Assign
PCH
AGCH
SDCCH
IMSI MSISDN
MSRN
MSRN
MSRN
TMSI
LAI &TMSI
TMSIRACH
Page ResponseSDCCH
TMSI
TMSI &
status
Status
Land to Mobile SequenceComplete Call
MS BSS MSC VLR HLR GMSC PST
-
7/31/2019 Training Gsm Basic[1]
146/176
146
SETUP
CALL Confirmation
ADDRESS COMPLETE
Assignment Command
Ring Toneat MS
Alert
Assignment Complete
Connect
TMSI
SDCCH
SDCCH
TCH
FACCH
Connect ACK
Channel Circuit
FACCH
SubscriberPicks Up
FACCH
ANSWER TCH
BILLING STARTSFACCH
Ringing Stops atLand Phone
RingTone atLand Phone
Hello
Mobile Initiated Call Clearing
MS BSS MSC VLR HLR PSTN FACCH
-
7/31/2019 Training Gsm Basic[1]
147/176
147
1 DISCONNECT
PSTN RELEASEMOBILE RELEASE
2 PSTN RELEASECOMPLETE
FACCH
FACCH
MOBILE RELEASE
COMPLETE
3 CLEAR COMMAND
CHANNEL RELEASE
5 RLSD
4UA
CLEAR COMPLETE
DISC
RELEASE COMPLETE
FACCH
FACCH
MS -MSC SignallingReleased
FACCH
FACCH
Inter-BSS Handover Sequence
-
7/31/2019 Training Gsm Basic[1]
148/176
148
1
3
Periodic MeasurementReports
Handover Required
Handover Request
Handover Req Ack
Information Interchange
Handover Complete
Clear Command
Handover Command
MS BSS BSS MSC HLR PSTN
SAACH
7
4
6
5
2 TMSI Cct.Code
HO ref No.
HO Ref No.
FACCH
FACCH
Periodic MeasurementsReports
SAACH
8
9
-
7/31/2019 Training Gsm Basic[1]
149/176
149
Radio Interface Optimization
-
7/31/2019 Training Gsm Basic[1]
150/176
150
Transmission Timing
Power Control
VAD and DTX
Multipath Fading
Equalization Diversity
Frequency Hopping
THREE TIMESLOT OFFSET
-
7/31/2019 Training Gsm Basic[1]
151/176
151
0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 7
Mobile Rx
Mobile Tx3 TS Offset
TIMING ADVANCE
-
7/31/2019 Training Gsm Basic[1]
152/176
152
6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5
BURST arrivesLATE
BURST arrivesIN TIME
BURST sent early
T = 3.69 S to 233 S
Cell Radius = 35km
Power Control
-
7/31/2019 Training Gsm Basic[1]
153/176
153
Cell Radius = 35km
In steps of 2dB
Enhances Battery Life
Reduces Interference
13 dBm (min)
33 dBm (max)
Dis-Continuos Transmission
-
7/31/2019 Training Gsm Basic[1]
154/176
154
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
VAD - Voice Activity Detection MS identifies presence/ absence of speech
Generates Comfort noise
DTX - Dis-Continuous TransmissionMS does not TX during silence period
MULTI-PATH PROPAGATION
-
7/31/2019 Training Gsm Basic[1]
155/176
155
DIVERSITY
-
7/31/2019 Training Gsm Basic[1]
156/176
156
Approx. 10 Wavelengths 3.3 meters
Diversity Receiver
FREQUENCY HOPPING
-
7/31/2019 Training Gsm Basic[1]
157/176
157
F0
F2
F3
F4
FN
F1
T I M E
F R E Q U E N C Y
FREQUENCY HOPPINGMobile Activity
-
7/31/2019 Training Gsm Basic[1]
158/176
158
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5
0 1 3 4 5 6 7 0 1 2 3 4 5 6 7
Mobile Rx
MONITORING Other Cell
6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5
Mobile Tx
Rx 1
Rx 2
Tx1
Tx2
-
7/31/2019 Training Gsm Basic[1]
159/176
159
Speech Services
Telephony (13 kbps full rate)
-
7/31/2019 Training Gsm Basic[1]
160/176
160
Telephony (13 kbps full rate)
Emergency Call (with/without SIM card in theMobile Station)
Short Message Services (SMS)
Point to Point (128 Byte Max.)
Cell Broadcast(75 bytes Max.)
Dual Personal and Business Numbers.
Allows calls to be made and billed, either tobusiness or personal numbers.
Data Services (Bearer Services)
D t t t d f t d
-
7/31/2019 Training Gsm Basic[1]
161/176
161
Data rates supported as of today are
2.4 Kbps
4.8 Kbps
9.6 Kbps
Supplementary Service - Call Waiting
-
7/31/2019 Training Gsm Basic[1]
162/176
162
Call in Progress
PSTN Phone
Supplementary Services - Call Hold
-
7/31/2019 Training Gsm Basic[1]
163/176
163
1. Call in Progress2. Put on Hold
3. Calls another Mobile
Supplementary Services -Call Forwarding
-
7/31/2019 Training Gsm Basic[1]
164/176
164
Incoming
Call
Voice Mail
System
PSTNPhone
AnotherMobile
Divert ifAll Calls
Busy
Not Reachable
No Answer
Supplementary Services
Calling Line Identification
-
7/31/2019 Training Gsm Basic[1]
165/176
165
Calling Line Identification Present Absent
Connect Line Identification
Present
Absent Closed User Group - CUG
Only incoming
Only outgoing Operator Controlled Barring
Voice Mail System
-
7/31/2019 Training Gsm Basic[1]
166/176
166
ANSWERING MACHINE
Voice Mail System
-
7/31/2019 Training Gsm Basic[1]
167/176
167
MSC
Short Message Service
-
7/31/2019 Training Gsm Basic[1]
168/176
168
SMSC
MSC
BTS
Short Message Service
-
7/31/2019 Training Gsm Basic[1]
169/176
169
SMSC
MSC
BTS
Point to Multipoint
Point to Point
PRE - PAID SYSTEM
SIM BASED
-
7/31/2019 Training Gsm Basic[1]
170/176
170
Data on SIM Decrements with use Over the air charging !!??
NETWORK BASED
Data secure on with the network Over the air re-charging Features
Inquiry Warnings ..
-
7/31/2019 Training Gsm Basic[1]
171/176
171
SEPARATE GSM & WLL INFRASTRUCTER
-
7/31/2019 Training Gsm Basic[1]
172/176
172
DUAL BAND / MODEHANDEST
MSC GSM BSC
GSM BTS
PSTN FIXED LINE SWITCH CDMA BSC
CDMA BTS
CDMA BTS
GSM BTS
SEPARATE GSM & WLL INFRASTRUCTER
-
7/31/2019 Training Gsm Basic[1]
173/176
173
GSM + CDMA
GSM GSM
CDMA
Call Drop.Toggle to GSM
Still on GSM.Toggle to WLL
GSM
On WLL
DUAL BAND / MODEHANDEST
GSMCoverage
CDMACoverage
Every individual is a WLL subscriberunder any and only one CDMA BTSand is a regular subscriber for the restof the GSM network in the whole ofPunjab.The subscriber also has the advantageof roaming within & outside thecountry.
COMMON GSM & CDMA INFRASTRUCTER
A - INTERFACE
-
7/31/2019 Training Gsm Basic[1]
174/176
174
DUAL BAND / MODEHANDEST
MSC
GSM BSCGSM BTS
PSTN
CDMA BSC CDMA BTS
A - INTERFACE
A - INTERFACE
IRRIDIUM
BTS in the Sky
-
7/31/2019 Training Gsm Basic[1]
175/176
175
LEO ~1400km Inter Satellite Links - 22.55GHz to 23.55GHz L-Band (1616MHz to 1626.5 MHz) Band Width - 10.5MHz
Use TDM/FDMA scheme World-Wide Coverage
60+ Now Operational Small Hand held terminals Dual Mobiles under development
-
7/31/2019 Training Gsm Basic[1]
176/176