Download - Basic of Telecom
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Basics Of TelecomInduction Program
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Mobile technology
What is GSM/CDMA/TDMA or difference between Tata indicom,reliance and Airtel, Hutch, !dea
Various mobility technologies GSM / GPRS / UMTS
CDMA CDMA-95, 1xRTT, 1xEVDO
Mostly different on the Radio Interface (how the handset talks overair)
Core network and its components follow similar framework
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You will also learn about
Network Architecture Air interface and core network
GSM network HLR
VLR
MSC (GMSC)
SMSC
EIR
Billing
IN
VAS
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Roaming
Roaming links
Network Architecture
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Telecom Technology Fundamentals
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Basic Telecom Network 2 subscribers
Customer premiseEquipment (Telephone)
Transmission media
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Basic Telecom Network Speech conversion
Speech
Electrical signal
Equivalent to
speech
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Basic Telecom Network7 Subscribers
A mess ?
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Mesh Connection of LEs
LE
LE LE
LE
LE LE
LE
LE Messy !
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Connection of LEs thru Tandem
LE
LE LE
LE
LE LE
LE
LE
Tandem
Exchange
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Switching Network
What is a Switching NW?
That part of a Telecom Network which connects to the Access network
and switches calls to the desired destination (in Access NW) as perdialed digits..
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Switching- Numbering plan
L.E
101
102
103
104
105106
107
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Architecture of a Telecom Network
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Local Exchange Network- Two Exchanges
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L.E
101
102
103
104
105106
10721
L.E
104
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Local Exchange NetworkEight Exchanges
LE
20
LE
21
LE
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LE
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LE
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LE
24
LE
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LE
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Tandem
Exchange
Exch. code
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Local Exchange Network
A Network where calls within its boundary are all charged at a Local
call rate is a Short Distance Charging Area (SDCA)
For eg. Pune City is an SDCA
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National Long Distance Network
TAX
TAX
TAX
TAX
LE
LE
LELE
LE
Mumbai
Delhi
Chennai
Kolkott
11
22
33
44
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International Longdistance Network
LE
TAX
TAX TAX
TAX
LE
LE
LE
International Gateway (IGY)
Mumbai
PuneNagpur
Mumbai
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International Telephone Numbering scheme
+ 91 20 6523138
International
Prefix
Country code
(India)
Area code
(Pune)
Subscriber
Number
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GSM- History
1970s- Bell labs invents Cellular Mobile Telephony
1980s- Nordic PTTs implement NMT 450 Cellular systems
1980s- UK implements TACS Cellular Mobile System
1980s- Germany implements C Netz Mobile system
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GSM History- cond
1990- GSM phase 1 specifications frozen
1991- GSM 1800 Mhz specs. Frozen
1992- January - First GSM Operator in Finland
1992 December- 13 Networks in operation
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Mobile Network
Mobile
Switching
Centre (MSC) Home LocationRegister (HLR)
Visitor Location
Register (VLR)
Radio
Base-station
Sub-system
(BSS)
MSC/VLR
MSC/VLR
Radio Network Core Network
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Network Architecture
PSTN
Data Terminal
HLR/
VLR
MSCBSC
OMC(Operation & Maintenance
Center)
OperationTerminal
BTS
HandsetAX.25
A-bis SS7
Network sub-system PSTNRadio
sub-system
Mobile
station
UM
SIMcard
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GSM Building Blocks- Description
DATA Bases
HLR- Home Location Register All Subscriber information
Services, Authentication parameters Location of MS (Mobile Station) MS sends this info vis MSC/VLR to HLR
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GSM Building Blocks- Description
VLR- Visitor Location Register Contains info about all MSs in MSC area As soon as MS roams into a new MSC area, VLR requests its HLR for
subscription data. Also its (MSs) HLR is informed about MSs currentlocation
AUC- Authentication Centre AUC provides Authentication parameters & ciphering keys to HLR
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GSM Building Blocks- Description
EIR- Equipment Identity Register Contains unique Hardware identity of Mobile equipment (IMEI) EIR checks whether the validity of the equipment.. Type approved, stolen etc..
Stolen and non type approved can be barred
MS- Mobile Station Mobile equipment + SIM (Subscriber Identity Module) SIM contains subscription, Authentication key and other details
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Some Terminology
HPMN Home Public Mobile Network VPMN Visited Public Mobile Network SMSC Short Message Service Center
BSS/OSS Business/Operations Support System GPRS General Packet Radio Service IN Intelligent Network Customers/Subscribers, Out-Roamers, In-Roamers IOT Inter Operator Tariff TAP Transferred Accounting Procedure
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HLR Home Location Register
A master database which stores permanent information onsubscriber irrespective of their location, including
Individual Subscriber Authentication Key (Ki) for each SubscriberIdentity Module (SIM)
Location (VLR)
Services subscribed to
Each IMSI is attached to MSISDN
Integrated and Standalone HLR
Authentication Center (AUC) - Computes auth. triplets
Revenue Leakage?
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VLR Visitor Location Register
Temporarily stores information for mobile subscribers/roamers whoare served/attached to a cell served by a MSC managed by this
VLR
Standalone VLR and Integrated VLR
Stores Location Area of subscriber
Data related to supplementary services Call forwarding, Call barring etc.
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MSC Mobile Switching Center
Also called the Switch
Controls multiple Base Stations; handles voice trunks
Responsible for setting up, routing and supervising calls to and fromthe mobile subscriber
GMSC is a MSC with a capability to: Interface between mobile and other networks
Query the HLR to terminate a call to a subscriber (which MSC/VLR isthe subscriber attached to?)
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GPRS General Packet Radio System
GGSN, SGSN are two network entities SGSN: Similar to VLR
GGSN: Similar to HLR
GRX GPRS Roaming Exchange Similar to SS7 Signaling Interconnect providers
Nearly 30 GRX providers in the world
Peering with each other in Amsterdam
APN Access Point Name Type of URL
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