Mobile communication - GSM/CDMA/WIMAX Technologies

MOBILE COMMUNICATION
A communication which does not depend on physical connection needed between two
communicating entities and have flexibility to move anywhere during communication is
called Mobile Communication. Currently, GSM and CDMA technology offers Mobile
Communication. Mobile Communication is one of the fastest growing telecommunication
industries which may never suffer from economics of the world.
Before discussing more about mobile communication, it is mandatory to know about mobile
handset and SIM.
MOBILE HANDSET (PHONE) - A mobile phone or cell phone is a device that can make and
receive telephone calls over a radio link while moving around a wide geographic area. A
mobile phone operator connects the mobile phone to a cellular network and then to the
public telephone network as well. It consists of a battery, keypad, SIM card, control unit, a
transceiver and an antenna system. Nowadays, mobile phones also provide other services
other than the principal service of telephony such as text messaging (SMS), Internet access,
MMS, camera, Bluetooth, Infrared, gaming, business applications, email, etc. The credit goes
to John F. Mitchell for demonstrating the first mobile phone.
SIM CARD- A smart card called SIM (Subscriber Identification Module) is an integrated
circuit used to identify the subscriber to the system, a secret key for authentication. By
inserting SIM card into a mobile handset, a user can receive and make calls and receive
other subscribed services as well. A SIM circuit is embedded into a removable plastic.
TERMINOLOGIES IN MOBILE COMMUNICATION
CELL- It is the smallest geographical area considered for mobile communication.
SUBSCRIBER- A mobile phone user who pays subscription charges for using a mobile
communication system.
MOBILE STATION- It is basically a mobile phone intended for use while moving anywhere.
BASE STATION- It provides connection between mobile unit and Mobile Switching Centre. It
is located in each cell.
CELL SPLITTING- In high cellular traffic regions, a larger cell is divided into smaller cells to
have complete radio coverage. This is called Cell Splitting.
HANDOFF- The handing over of call in progress from one base transreceiver to another one
when mobile unit moves from one cell to another so that continuity of call is maintained is
called Handoff Mechanism.

CLUSTER- A group of cells is called cluster. Generally, a cluster of 7 cells is preferred.
CELLULAR FREQUENCIES and SPECTRUM- All cellular phone networks worldwide use a
portion of the radio frequency spectrum for the transmission and reception of their signals.
This is also shared with television, Wi-Fi and Bluetooth transmission. The cellular
frequencies are the sets of frequency ranges within the ultra high frequency band that have
been allocated for cellular phone use. Radio Frequency Spectrum refers to the full frequency
range from 3 kHz to 300 GHz that may be used for wireless communication. RF spectrum is a
national resource. Each telecom company is allocated a specific frequency spectrum for
enabling communication to its subscribers. They have to pay a huge amount in order to buy
a specific frequency band or spectrum. For a GSM system, two frequency bands of 25 MHz
each are allocated as,
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890-915 MHz for the uplink (Mobile station to Base Station)
935-960 MHz for the downlink (Base Station to Mobile Station)
The allocated frequency spectrum for BSNL lies in the 2.5 GHz frequency band.

FREQUENCY REUSE- The process of using the same set of frequencies allocated to more
than one cell is called Frequency Reuse. This concept is followed for the efficient spectrum
utilization. Frequency reuse is applied between the cells of different cell clusters.
TRAFFIC CHANNELS and CONTROL CHANNELS- A frequency channel consists of a pair of
frequency bands (one band is in low band and other is in high band). Traffic Channels are
used for carrying data or voice connections between different users while Control Channels
are for necessary exchange of information related to setting up and establishing cell base
stations and the mobile units.
FORWARD CHANNEL and REVERSE CHANNEL- Forward Channel is a radio channel used for
transmission of information from base station to the mobile unit, while Reverse Channel
transmits the information from the mobile unit to base station.
ROAMER- It is a mobile station that operates in a service area other than the subscribed
service area is called Roamer.
SIMPLEX, HALF DUPLEX and FULL DUPLEX SYSTEMS- Communication systems providing
only one way of communication are called Simplex Systems, those allowing two way
communication but only one at a time by using same radio channel for transmission and
reception are called Half Duplex Systems. The systems using two different radio channels for
transmission and reception and allowing two ways communication is called Full Duplex
System.

OPERATION of CELLULAR MOBILE SYSTEM
Operation of a cellular mobile system is completed into five stepsMOBILE UNIT INITIALIZATION- When a subscriber activates mobile unit, the receiver scans
21 set-up channels among 416 channels. The strongest channel is selected and locks on the
for certain time. This strongest channel is from the nearest cell site and it is in idle stage.
This feature is called self location scheme. The self location scheme is user independent.
This eliminates the load on transmission at cell site for locating mobile unit. No location
information of idle mobile units appears at each cell sites. Hence, the paging process is
longer when call initiates from land line to mobile unit.
MOBILE ORIGINATED CALL-A mobile subscriber enters the called number into originating
register of mobile unit where it is checked to see that number is correct or not on pressing
send button. If the number is correct a request for service is sent on setup channel obtained
from self-location scheme. The cell site receives this request and selects the best directional
antenna for voice channel to use. Simultaneously cell site sends a request to mobile
telephone switching office (MTSO) on high speed data link. MTSO selects an appropriate
channel for the call and cell site directs to mobile unit.
NETWORK ORIGINATED CALL-A land line subscriber dials a mobile unit number. Telephone
office recognizes it as mobile number and forwards the call to MTSO. The MTSO sends a
paging message to few cell sites depending on mobile number and search algorithm. Each
cell transmits the page on its set up channel. The mobile unit recognizes its own ID on a
strong setup channel and responds to cell site. The mobile unit follows the instruction to
tune to assigned voice channel and initiate user alert to respond to the call of the user.
CALL TERMINATION-When mobile user turns off mobile unit, a particular signal is
transmitted to cell site. Then both sides free the voice channel. The mobile unit resumes
monitoring pages through the strongest channel.
HANDOFF PROCEDURE-As mobile moves out of cell coverage area the reception becomes
weak. The cell site calls for handoff i.e. system switches the call to a new frequency channel
in new cell site without interrupting and knowing the user. The call continues without
interruption.
GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS (GSM)
GSM is a feature rich, digital wireless technology. GSM provides subscribers with highquality digital wireless phone service and clarity, as well as enhanced call security and
privacy. This technique is most widely used for digital cellular radio. A GSM system has

maximum 200 full duplex channels per cell. Each channel has different uplink and downlink
frequencies. GSM handles channel access using a combination of slotted ALOHA, TDM and
FDM.
Developed in Europe, GSM is a second generation (2 G) cellular system which uses
digital modulation and network level architectures and services. Commercial services of
GSM started in mid-1991. It can handle both, voice and data traffic, the voice waveform
being digitally encoded before transmission. GSM transmission is done within frequency
bands of 900 MHz, 1800 MHz and 1900 MHz.
FEATURES of GSM
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Ability to use same phone in different networks.
Data transmission and reception at 9600 bps speed.
SMS (Short Message Service) facility allowing sending and receiving 126 character
text message
FAX transmission and reception
Rapid call setup
More subscriber capacity in the given spectrum
Smaller handsets
Encrypted conversions that cannot be tapped
Number identification services
Call forwarding, call holding and conference facility
Call restriction services
Videotext and teletext transmission
Emergency services by notifying nearest emergency-service provider by dialling
three digits
Access to users on POTS (Plain Old Telephone Service)
GSM RADIO LINK ASPECT

The 25 MHz bandwidth is further divided into 124 carrier frequency channels each 200 kHz
apart called ‘Absolute Radio Frequency Channel Numbers’ (ARFCN). The ARFCN indicates a
pair of channel which isseparated by 45 MHz. Each channel is time shared between 8
subscribers in TDMA scheme with frame duration of 4.615 milisecond. Radio transmission
on both forward and reverse link are made at channel data rate of 270.833 kbps, using BT=
0.3 GMSK modulation. Therefore, signalling bit period= 3.692 microsecond and effective
transmission rate per user is 33.854 kbps. But, user data is sent at a maximum rate of 24.7
kbps because of GSM overload.

Every time slot (TS) has 4156.25 bits, out of which 8.25 bits are used for guard time and 6
bits are used for start and stop bits to prevent overlap with adjacent time slots. Each time
slot has duration of 576.92 micro second.
Bits= 3

ST

57

1

26

DATA

S

T

1

57

S

DATA

TS4

TS5

3

8.25

SP

G

TIME SLOT
Total number of bits= 156.25
ST= Start bits
SP= Stop bits
S= Stealing bits
T= Training bits
G= Guard bits
TS0

TS1

TS2

TS3

TS6

TS7

GSM FRAME
8 time slots of 0.577 ms each
GSM ARCHITECTURE
A GSM network consists of several functional entities, whose functions and interfaces are
specified.

MOBILE STATION (MS)- Mobile Station consists of a mobile unit and SIM card discussed
earlier. Each mobile equipment or unit is uniquely identified by the International Mobile

Equipment Identity (IMEI) number. SIM card is uniquely identified by the International
Mobile Subscriber Identity (IMSI) number. The IMEI and IMSI are independent, thereby
allowing personal mobility. The SIM may be protected against unauthorized use by a
password or Personal Identity Number (PIN).
The power levels supported by GSM MS currently range from 0.8 to 8.0 W.
BASE STATION SUBSYSTEM (BSS) – It is called access network. The BSS comprises of,

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Base Transceiver System (BTS)
Base Station Controller (BSC)

Abis interface exists between BTS and BSC, while Um interface is present between MS and
BTS. The interface comprises of traffic and control channels. Um interface is also called radio
or air interface.Abis interface may be a modem, radio or optical fibre. This interface is
defined by GSM equipment manufacturer. The equipment is manufactured by ALCATEL for
BSNL. The function of BTS and BSC is given asBTS
It handles radio link protocols with MS.
It performs interleaving and deinterleaving.
It enables full duplex communication to
MS.
It contains Transcoder Rate Adapter Unit
(TRAU), in which GSM specific speech
encoding and decoding is carried out.

BSC
It manages the radio resources of one or
more BTSs.
It handles radio-channel setup, frequency
hopping and handoffs.
It connects MS and MSC.
It controls the operation of BTSs.

NETWORK and SWITCHING SUBSYSTEM (NSS) – It is called core network. NSS includes data
bases required for subscribers and mobility management as well as switching and routing.
The main components of NSS are

MOBILE SWITCHING CENTER – MSC performs the function of switching. It connects
the subscriber with another subscriber or PSTN. It also performs the function of call
setup, supervision and release along with digit collection, translation, billing
information collection, registration, echo cancellation and local updating.
Any call made by subscriber first comes to MSC and then it is routed to the
desired subscriber.
In Madhya Pradesh, BSNL has four MSCs operating at Indore, Bhopal, Gwalior and
Jabalpur.

Bhopal has two MSCs of BSNL, Arera MSC and Saket Nagar MSC. ‘A’ interface is
used between MSC and BSC. These are physically connected by leased lines or
microwave links. The physical layer of is a 2 Mbps CCITT digital connection. The ‘A’
interface allows a service provider to use base stations and switching equipment
made by different manufacturers.
HOME LOCATION REGISTER (HLR)-HLR contains all the administrative information
of each subscriber registered in the corresponding GSM network, along with
current location of MS. The HLR database maintains IMSI of each subscriber and
VLR address. There is logically one HLR per GSM network. HLR database is of two
types- Dynamic and Permanent.
VISITOR LOCATION REGISTER (VLR) – VLR is a temporary database that stores the
IMSI and customer information for each roaming subscriber who is visiting the
coverage area of a particular MSC. When a roaming mobile enters in MSC area, the
MSC informs the associated VLR about the mobile and this information is
registered.
The temporary subscriber information in VLR includes IMSI
 Features currently activated
 Temporary mobile subscriber identity (TMSI)
 Current location information about MS
 Location where mobile is registered
 Copy of subscriber data from HLR.
 MS ISDN number

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EQUIPMENT IDENTITY REGISTER (EIR) – EIR is a database that contains a list of
all valid mobile equipments on the network identified by IMEI numbers. An IMEI
is marked as invalid if it has been reported stolen or is not approved.
White list
Valid IMEI numbers
Grey list
IMEI under suspicion
Black list
Prohibited IMEI numbers



AUTHENTICATION CENTER (AuC) – AuC is a protected database that stores a
copy of the secret key stored in each subscriber’s SIM card, which is used for
authentication and encryption over radio channel.

OPERATION and SUPPORT SUBSYSTEM (OSS) – OSS is the command centre used to monitor
and control GSM system. Main functions of OSS are
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Network support and maintenance
Subscription management (charging and billing)

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Mobile equipment and BTS management.
If any emergency occurs at BTS, the OSS determines the location of the BTS, and
the failure occurred.
COMPONENTS OF BTS

BTS is a set of equipments that facilitates wireless communication. A BTS in general consists
of Trans-receiver module, Antenna Network Combiner, Controller (SUMA) and Alarm
Extension System (XIBM). It is a self contained unit for transmitting and receiving signal for
mobile communication.
Types of BTS:
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Indoor BTS
Outdoor BTS
Dual Band BTS
Twin TRX BTS
Indoor BTS is placed in a shelter and Air condition is a must as it is very
sensitive to temperature. On the other hand, no shelter is required for
outdoor BTS and Air condition is also not a must.

BSNL uses the equipments manufactured by ALCATEL.
BTS SHELTER- Shelter is a portable sealed cabin made up of sandwiched insulated panels
with polyurethane as filler material between galvanized pre-coated steel sheets. Floor is
made up of 19mm thick marine plywood and is covered with PVC antistatic flooring. MS
tube is reinforced inside floor panel for higher floor load capacity.Secondary slanting roof is
provided to protect primary roof from direct sunlight and rainwater. Door is fixed with
heavy-duty hinges, and is equipped with hydraulic closer and three way locking
arrangement.

ROOF TOP TOWER- This is manufactured into Square Lattice Type and Triangular type. All

members of RTT are made up of structural steel as per IS2062 Grade A & hot dip Zinc
galvanized as per IS 4759.
It can carry 6 numbers of GSM/WLL Antenna and 3 numbers of 0.6 diameter Microwave
Antenna. It can survive wind velocity up to 210 km/h for short duration.

TRANSCEIVER- Alcatel’s new Twin TRX radio transceiver doubles the capacity of existing
equipment, while occupying the same space in the rack. The new Twin TRX is particularly
adapted for densely populated urban areas, with a maximum capacity of 24 TRX per Base
Station cabinet.Twin TRX transceivers can be installed in the full range of Alcatel’s indoor
and outdoor BTS.

ANTENNA NETWORK COMBINERANC performs combination of signal from multiple
antennas or amplifiers. These are high quality coaxial combiners available in various
configurations covering full octave bands from 700MHz to 2.5 GHz. These units are ideally
suited for use in Cellular PCS and Wi-Fi systems. All have N female terminations, can handle
10 watts of power and provides 20dB of isolation between ports.

Antenna Network Combiner ensures the combiner and duplex functions.
TRANSCODER and RATE ADAPTATION UNIT
Transcoder and Rate Adaptation Unit (TRAU), performs transcoding function for speech
channels and Rate Adaptation for data channels in the GSM network. TRAU is a data rate
conversion unit. The PSTN/ISDN switch is a switch for 64 kbps voice. Current technology
permits to decrease the bit-rate (in GSM radio interface it is 13kbit/s for full rate and
6.5kbit/s for half rate). Since MSC is basically a PSTN/ISDN switch its bit-rate is still 64kbit/s.
That is why a rate conversion is required in between the BSC and MSC
Transcoding is the compression of speech data from 64kbit/s to 13/12.2/5.6kbit/s in case
FR/EFR/HR (respectively) speech coding.For an MS-to-MS call, the transmission path covers
the radio access network (RAN) as well as the core network (CN). Since the transmission
modes and coding standards are different for RAN and CN, speech data is converted at the
transition points from RAN to CN. This conversion is performed in the TRAU network
element which connects RAN and CN.
13kbit/s for FR (Full Rate), Redundancy (Channel Coding) = 9.8kbit/s
=> Gross data rate after adding redundancy = 22.8kbit/s
= 12.2kbit/s for EFR (Enhanced Full Rate),
Redundancy (Channel Coding) = 10.6kbit/s
TRAU changes the bit rate of 16kbit/s of the BSS side to 64kbit/s of NSS side.
= 5.6kbit/s for HR (Half Rate), Redundancy (Channel Coding) = 5.8kbit/s

3G TECHNOLOGY
3G stands for third generation is the third generation of mobile telecommunications
technology. 3G telecommunication networks support services that provide an information
transfer rate of at least 2Mb/s. However, many services advertised as 3G provide higher
speed than the minimum technical requirements for a 3G service. Recent 3G releases, often
denoted 3.5G and 3.75G, also provide mobile broadband access of several Mb/s to smart
phones and mobile modems in laptop computers. 3G is also called Wideband CDMA or WCDMA.
3G finds application in wireless voice telephony, mobile Internet access, wireless Internet
access, video calls and mobile TV.Services advertised as 3G are required to meet IMT-2000
technical standards, including standards for reliability and speed (data transfer rates).
FEATURES of 3G

DATA RATE-ITU has not provided a clear definition of the data rate users can expect

from 3G equipment or providers. Thus users sold 3G service may not be able to point
to a standard and say that the rates it specifies are not being met. It is expected that
IMT-2000 will provide higher transmission rates: a minimum data rate of 2Mb/s for
stationary or walking users, and 384kb/s in a moving vehicle, the ITU does not
actually clearly specify minimum or average rates or what modes of the interfaces
qualify as 3G, so various rates are sold as 3G intended to meet customers’
expectations of broadband data.
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SECURITY-3G networks offer greater security than their 2G predecessors. By

allowing the User Equipment to authenticate the network it is attaching to, the
user can be sure the network is the intended one and not an impersonator. 3G
networks use theKASUMI block cipher instead of the older A5/1 stream cipher.
However, a number of serious weaknesses in the KASUMI cipher have been
identified.
In addition to the 3G network infrastructure security, end-to-end security is offered
when application frameworks such as IMS are accessed, although this is not strictly a
3G property.
GPRS
General packet radio service (GPRS) is a packet oriented mobile data service on
the2G and 3G cellular communication system's global system for mobile
communications (GSM). GPRS was originally standardized by European Telecommunications
Standards Institute (ETSI). It is now maintained by the 3rd Generation Partnership
Project (3GPP). It provides services midway between 2G and 3G. Hence, it is also termed as
2.5G. The data transfer takes place at the rate of 128 kbps. GPRS usage is typically charged
based on volume of data transferred, contrasting with circuit switched data, which is usually
billed per minute of connection time.
GPRS extends the GSM Packet circuit switched data capabilities and makes the following
services possible-

1. "Always on" internet access
2. Multimedia messaging service (MMS)
3. Internet applications for smart devices through wireless application
protocol (WAP)
4. Point-to-point (P2P) service: inter-networking with the Internet (IP)
5. SMS messaging and broadcasting
If SMS over GPRS is used, an SMS transmission speed of about 30 SMS messages per minute
may be achieved. This is much faster than using the ordinary SMS over GSM, whose SMS
transmission speed is about 6 to 10 SMS messages per minute.
GPRS supports the following protocols:
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Internet protocol (IP).
 Point-to-point protocol
 X.25 connections
When TCP/IP is used, each phone can have one or more IP addresses allocated. GPRS will
store and forward the IP packets to the phone even during handover. The TCP handles any
packet loss (e.g. due to a radio noise induced pause). A GPRS connection is established by
reference to its access point name (APN). The APN defines the services such as wireless
application protocol(WAP) access, short message service (SMS), multimedia messaging
service (MMS), and for Internet communication services such as email and World Wide
Web access.
EDGE
EDGE (also known as Enhanced GPRS or EGPRS) is a data system used on top of GSM
networks. It provides nearly three times faster speeds than the outdated GPRS system. The
theoretical maximum speed is 473 kbps for 8 timeslots but it is typically limited to 135 kbps
in order to conserve spectrum resources. Both phone and network must support EDGE;
otherwise the phone will revert automatically to GPRS.
EDGE meets the requirements for a 3G network but is usually classified as 2.75G. EDGE is
standardized also by 3GPP as part of the GSM family. EDGE delivers higher bit-rates per
radio channel, resulting in a threefold increase in capacity and performance compared with
an ordinary GSM/GPRS connection. EDGE can be used for any packet switched application,
such as an Internet connection. EDGE is a superset to GPRS and can function on any network
with GPRS deployed on it, provided the carrier implements the necessary upgrade. EDGE
requires no hardware or software changes to be made in GSM core networks. EDGEcompatible transceiver units must be installed and the base station subsystem needs to be
upgraded to support EDGE. If the operator already has this in place, which is often the case
today, the network can be upgraded to EDGE by activating an optional software feature.
Today EDGE is supported by all major chip vendors for both GSM and WCDMA/HSPA.
In addition to Gaussian minimum-shift keying (GMSK), EDGE uses higher-order PSK/8
phase shift keying (8PSK) for the upper five of its nine modulation and coding schemes.
EDGE produces a 3-bit word for every change in carrier phase. This effectively triples the

gross data rate offered by GSM. EDGE, like GPRS, uses a rate adaptation algorithm that
adapts the modulation and coding scheme (MCS) according to the quality of the radio
channel, and thus the bit rate and robustness of data transmission. It introduces a new
technology not found in GPRS, Incremental Redundancy, which, instead of retransmitting
disturbed packets, sends more redundancy information to be combined in the receiver. This
increases the probability of correct decoding.
EDGE can carry a bandwidth up to 236kb/s (with end-to-end latency of less than 150 ms)
for 4 timeslots (theoretical maximum is 473.6kb/s for 8 timeslots) in packet mode. This
means it can handle four times as much traffic as standard GPRS. EDGE meets
the International Telecommunications Union's requirement for a 3G network, and has been
accepted by the ITU as part of the IMT-2000 family of 3G standards. It also enhances the
circuit data mode called HSCSD, increasing the data rate of this service.
UNIVERSAL MOBILE TELECOMMUNICATIONS SYSTEM
Commonly abbreviated as UMTS, Universal Mobile Telecommunications Systemis a third
generationmobile cellular system for networks based on the GSM standard. Developed and
maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of
the International Telecommunications Union IMT-2000 standard set and compares with the
CDMA2000 standard set for networks based on the competing CDMA Onetechnology. UMTS
uses (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth
to mobile network operators.UMTS includes the original W-CDMA scheme using paired or
unpaired 5 MHz wide channels in globally agreed bandwidth around 2 GHz, though
subsequently, further bandwidth has been allocated by the ITU on a regional basis.

The UMTS Radio Access Network (UTRAN) technology is specified in the 3GPPTM TS 25.series specifications. The specifications cater for Frequency Division Duplex (FDD) and Time
Division Duplex (TDD) forms, with high (3.84 Mc/s) and low (1.28 Mc/s) chip rate flavours.
AS a development of the original radio scheme, a high speed download packet access
(HSDPA, offering download speeds potentially in excess of 10 Mb/s), and an uplink
equivalent (HSUPA, called as EDCH) were developed. Collectively, the pair called HSPA
permits the reception of multimedia broadcast/multicast, fixed-line broadband internet
access, interactive gaming and business applications. The radio frames are divided into 2ms
sub frames of 3 slots, and gross channel transmission rates are around 14Mb/s.
NODE B
Node B is a term used in UMTS (Universal Mobile Telecommunications System) equivalent
to BTS in GSM. It can be coined as ‘BTS of 3G’. It is the hardware that is connected to the
mobile phone network that communicates directly with mobile handsets. In contrast with
GSM base stations, Node B uses WCDMA/TD-SCDMA as the air interface technology. As in

all cellular systems, such as UMTS and GSM, the Node B contains radio
frequency transmitter/s and the receiver/s used to communicate directly with mobile
devices, which move freely around it. In this type of cellular network, the mobile devices
cannot communicate directly with each other but have to communicate with the Node
B.WCDMA technology enables the cells of same or different Node Bs and those controlled
by different RNC to overlap and still use the same frequency pair. Soft handovers make use
of this effect. Power requirements on Node Bs and user equipment (UE) are much lower. It
is connected to RNC of UMTS network through IUB interface. A full cell site has a cabinet, an
antenna mast and actual antenna. An equipment cabinet contains e.g. power
amplifiers, digital signal processors and backup batteries. A Node B can serve several cells,
also called sectors, depending on the configuration and type of antenna. Common
configuration include Omni cell (360°), 3 sectors (3x120°) or 6 sectors (3 sectors 120° wide
overlapping with 3 sectors of different frequency).

RADIO NETWORK CONTROLLER
The Radio Network Controller (RNC) is a governing element in the UMTS radio access
network (UTRAN) and is responsible for controlling the Node Bs that are connected to it.
The RNC carries out radio resource management, some of the mobility
management functions and is the point where encryption is done before user data is sent to
and from the mobile. The RNC connects to the Circuit Switched Core Network through
Media Gateway (MGW) and to the SGSN (Serving GPRS Support Node) in the Packet
Switched Core Network.In a relationship to a UE (in a soft handover situation) an RNC can
play two different roles. These are:
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D-RNC: Drift RNC
S-RNC: Serving RNC

However, as far as the Node B is concerned, the RNC may play a third role:


C-RNC: Controlling RNC

One RNC can assume more than one role at any time. An RNC also control the power of a

NODE B.The logical connections between the network elements are known as interfaces. The
interface between the RNC and the Circuit Switched Core Network (CS-CN) is called Iu-CS
and between the RNC and the Packet Switched Core Network is called Iu-PS. Other
interfaces include Iub (between the RNC and the Node B) and Iur (between RNCs in the
same network). Iu interfaces carry user traffic (such as voice or data) as well as control
information (see Protocols), and Iur interface is mainly needed for soft handovers involving 2
RNCs though not required as the absence of Iur will cause these handovers to become hard
handovers.

RADIO NETWORK CONTROLLER (NODE B)

LUB Interface
Iub interface connects Node B and RNC.The physical interface to a base station will be such
that the Iub capacityfrom a given base station has some discreet value.Because of signalling,
O&M, and ATM overhead, the Iub interfaceshould be sized to a bandwidth that is almost
twice that of the actual rawuser traffic. Of course, the user traffic is likely to be
asymmetrical, and weare likely to find that the downlink traffic is greater than the uplink
traffic. The actual Iub transmission facilities, however, will be symmetrical. Inother words, if
there are 2 Mbps capacity on one direction, there is also 2Mbps in the other direction.
Therefore, when dimensioning the Iub, we needonly to consider the user traffic in one
direction—the direction of greaterdemand. This will usually be the downlink direction.

OPERATIONS and MAINTENENCE CENTRE
Operations and Maintenance Centre (OMC) is the central location to
operate and maintain the network. There are various types of OMCs
depending on the functionality:

i.
ii.
iii.
iv.
v.
vi.

OMC-B (for maintaining Node B)
OMC-R (radio for maintaining RNC)
UMTS OMC-U
GPRS OMC-G
OMC-DO
OMC-IP
PLANNING and OPTIMISATION

GSM Radio Network Planning and Optimization provides a solid understanding of how to
design and plan a high quality GSM radio network. This includes expansion of network,
techniques to boost capacity, lowering interference and increasing quality in the network.
Macro cell planning is emphasised.Planning is the process of assigning frequencies,
transmitter locations and parameters of a wireless communications system to provide
sufficient coverage and capacity for the services required. The RF plan of a cellular
communication system has two objectives: coverage and capacity. Coverage relates to the
geographical footprint within the system that has sufficient RF signal strength to provide for
a call/data session. Capacity relates to the capability of the system to sustain a given
number of subscribers. Capacity and coverage are interrelated. To improve coverage,
capacity has to be sacrificed, while to improve capacity, coverage will have to be sacrificed.
Planning consists of four stages1.INITIAL RADIO LINK BUDGETING- The first level of the RF planning process is a budgetary
level. It uses the RF Link Budget along with a statistical propagation model. The statistical
propagation model does not include terrain effects and has a slope and intercept value for
each type of environment. This fairly simplistic approach allows for a quick analysis of the
number of sites that may be required to cover a certain area. Estimated Number of Sites is
the output produced at this stage.
2.DETAILED RF PROPAGATION MODELLING- The second level of the RF Planning process
relies a more detailed propagation model. Automatic planning tools are often employed in

this phase to perform detailed predictions. The propagation model takes into account the
characteristics of the selected antenna, the terrain, and the land use and land clutter
surrounding each site. Since these factors are considered, this propagation model provides a
better estimate of the coverage of the sites than the initial statistical propagation model.
3.FINE TUNING and OPTIMISATION-This stage includes items such as collecting drive data
to be used to tune or calibrate the propagation prediction model, predicting the available
data throughput at each site, fine tuning of parameter settings (e.g. antenna orientation,
down tilting, frequency plan). This process is required in the deployment of the system or in
determining service contract based coverage. Following is a typical list of outputs produced
at this stage:




A final List of Sites and Site Locations (and Height)
Optimised Antenna Directions and Down tilts
An optimised Neighbour Cell Lists for each site





Mobility (Handover and Cell Reselection) Parameters for each site
An optimised Frequency Plan
Detailed Coverage Predictions (e.g. Signal Strength (RSRP), Signal Quality (RSRQ)
Best CINR, Best Server Areas, Uplink and Downlink Throughput

4. CONTINOUS OPTIMISATION-The final phase of the RF planning process involves
continuous optimisation of the RF plan to accommodate for changes in the environment or
additional service requirements (e.g. additional coverage or capacity). This phase starts from
initial network deployment and involves collecting measurement data on a regular basis
that could be via drive testing or centralised collection. The data is then used to plan new
sites or to optimize the parameter settings (e.g. antenna orientation, down tilting,
frequency plan) of existing sites.
Radio Frequency Optimization is a process through which different soft (Cell Reselect
Offset, BTS power) and hard (e.g. Electrical Tilt, Mechanical Tilt, Azimuth etc.) parameters of
the Base transceiver stations are changed in order to improve the coverage area and
improve quality of signal. Besides that there are various key performance indicators which
have to be constantly monitored and necessary changes proposed in order to keep KPIs in
agreed limits with the mobile operator.
OVERVIEW of MOBILE TECHNOLOGIES
Mobile technology makes living life on the go easier. Gone are the days of being tied to a
desk or staying close to a landline phone to avoid a missed call. Communication,
entertainment, exercising and travel are merely a few lifestyle improvements made possible
with mobile technology.

Mobile phones are the most obvious mobile devices and are available to millions and
millions of people. Callers are almost instantly connected to each other through a series of
cellular connections that reach even to the most remote areas of the world. These cellular
connections are not only for mobile phones. Laptops and PDAs share data across the cellular
system. In fact, some Smart phones act as modems for laptops. Expensive connection to the
internet or to a network is not always necessary. Small MP3 players store hundreds of
songs. PDAs take the place of bulky day planner systems, address books and photo albums.
Portable handheld televisions pickup broadcasts of sports events, news shows and soap
operas.
GPS Receivers have gained tremendous popularity replacing those hard to refold paper
maps. Long battery life and tiny footprints make finding your direction easier in your vehicle.
Whether you need to plan a route across the county or whether you need to find a good

restaurant a GPS device offers a helping hand.
MOBILE TECHNOLOGY DEVICES

Cell phones



Smartphones/PDA phones



Laptop computers



PDAs



MP3 players



Handheld televisions



GPS (Global Positioning System)

INSIDE A MOBILE PHONE-Mobile phones are some of the most intricate devices people play
with on a daily basis. Modern digital mobile phones can process millions of calculations per
second. An amazing circuit board containing the brains of the phone







An antenna
A liquid crystal display (LCD)
A keyboard (not unlike the one you find in a TV remote control
A microphone
A speaker
A battery

The circuit board is the heart of the system. Here is one from a typical Nokia digital phone:

The front of the circuit board The back of the circuit board

The analog-to-digital and digital-to-analog conversion chips translate the
outgoing audio signal from analog to digital and the incoming signal from digital
back to analog. The digital signal processor (DSP) is a highly customized

processor designed to perform signal-manipulation calculations at high
speed.The microprocessor handles all of the housekeeping chores for the
keyboard and display, deals with command and control signalling with the base
station and also coordinates the rest of the functions on the board.
The ROM and Flash memory chips provide storage for the phone's operating
system and customizable features, such as the phone directory. The radio
frequency (RF) and power section handles power management and recharging,
and also deals with the hundreds of FM channels. Finally, the RF
amplifiers handle signals travelling to and from the antenna.

Microprocessor

CONNECTION of MOBILE DEVICES with NETWORK or INTERNET-









Bluetooth
Wi-Fi (Local Area) - Hot Spots
Broadband (Wide Area) - Air Card
VPN
3G Cell phone
Dial Up
Satellite

UPSIDES OF MOBILE TECHNOLOGY-








Time saving
Information sharing
Freedom of movement
Safety
Improved customer service
Improved productivity

DOWNSIDES OF MOBILE TECHNOLOGY

Cost



Distraction



Security threats



Theft



Short battery life



Disposal of spent batteries



Data loss

INFRASTRUCTURE
Telecommunications infrastructure refers to telecommunications spaces (e.g. rooms) and
pathways (e.g. conduit, cable tray), cables and related components such as jacks, crossconnection hardware, etc. When a telecommunications infrastructure is designed following
a holistic approach, the designer has created a single integrated infrastructure serving the
entire building.
In contrast, when a telecommunications infrastructure is designed following a non-holistic
or legacy approach, the building's telecommunications infrastructure is a piece-meal
collection of separate telecommunications infrastructures, each serving the specific space
occupied by an individual tenant or department.
Telecom Infrastructure is classified into two types-

ACTIVE INFRASTRUCTURE- Active infrastructure compares the core clement of cellular
telephony in the form of a network and contiguous radio cells providing coverage through
operating on dedicated set of radio channels of defined frequency. Elements of the active
infrastructure are the basic transceiver station (BTS), the base station controller (BSC), the
mobile switching centre (MSC), and microwave and GSM antenna along with telecom
equipments and routers. The antenna enables both the transmission and reception of the
radio signal, enabling the cellular telephony to proceed interrupted as the subscriber is
mobile.
PASSIVE INFRASTRUCTURE- Passive infrastructure comprises of the elements which enable
the active infra to operate as described above .The telecom towers are used for hosting the
antenna to predetermined and technically viable heights for optimum coverage of cellular
network. The towers are typically elected at site themselves and also comprise poles for
mounting the antennas, shelters and house for electrical and telecom equipment.
Passive infrastructure can be divided as1. Air Conditioners- Air Conditioners are used to prevent the components and
hardwares from high temperature and heat so that they may not be
damaged and the temperature of the room where components are placed
should remain moderate.
Freon is an element used in air conditioners. The temperature is maintained
at (22+3)0 C to (22-3)0C.
2. Tower- A cell site or Tower is a cellular telephone site where antennas and
electronic communications equipment are placed, usually on radio mast or
other high place, to create a cell in a cellular network. The elevated structure
typically supports antennas, and one or more sets of transmitter
/receivers transceivers, digital signal processors, control electronics, a GPS
receiver for timing (for CDMA2000/IS-95 or GSM systems), primary
and backup electrical power sources, and sheltering.
3. Power Supply- Power Supply is a must for any instrument to work in
Telecom. Two types of Power Supplies are used DC Power Supply- This is also called uninterrupted power
supply. It is used for the operation of BTS, BSC, MSC,etc and
providing power to media gateways and recharge the battery
as well.
 AC Power Supply- This power supply is taken from the main
line. Any telecom operator has to pay a huge amount (above
10lacs) to the power supplying company in order to use the
power needed for air conditioners, components and telecom
equipments, electricity, etc. This supply is needed to feed
servers, routers and switches.

The AC power coming from the transmission line feeder is given to step down transformer
to reduce its voltage level as all telecom equipments in exchanges, MSCs, BTSs, etc operate
on -48V DC supply. This alternating voltage is then passed through rectifiers to get
converted into pulsating DC voltage, and then to filter to get pure DC supply. To get
regulated DC power supply, Regulator is also used.
The unused DC power supply is converted into AC by invertor to act as Backup or UPS.
TRANSMISSION MEDIA
MULTI LABEL PROTOCOL SWITCHING
It is a part of Data Communication. Multiprotocol Label Switching (MPLS) is a mechanism in
high performance telecommunications networks that directs data from one network node
to the next based on short path labels rather than long network addresses, avoiding
complex lookups in a routing table. The labels identify virtual links (paths) between distant
nodes rather than endpoints. MPLS can encapsulate packets of various network protocols.
MPLS supports a range of access technologies, including T1/E1, ATM, Frame Relay, and DSL.
Packet-forwarding decisions are made solely on the contents of this label, without the
need to examine the packet itself. This allows one to create end-to-end circuits across any
type of transport medium, using any protocol. The primary benefit is to eliminate
dependence on a particular OSI model data link layertechnology, such as Asynchronous
Transfer Mode (ATM), Frame Relay, Synchronous Optical Networking (SONET) or Ethernet,
and eliminate the need for multiple layer-2 networks to satisfy different types of traffic.
MPLS belongs to the family of packet-switched networks.MPLS operates at a layer that is
generally considered to lie between traditional definitions of layer 2 (data link layer) and
layer 3 (network layer), and thus is often referred to as a "layer 2.5" protocol. MPLS
attempts to preserve the traffic engineering and out-of-band control that made Frame Relay
and ATM attractive for deploying large-scale networks.
While the traffic management benefits of migrating to MPLS are quite valuable (better
reliability, increased performance), there is a significant loss of visibility and access into the
MPLS cloud for IT departments. MPLS works by prefixing packets with an MPLS header,
containing one or more labels. This is called a label stack. Each label stack entry contains
four fields:


A 20-bit label value.



A 3-bit Traffic Class field for QoS (quality of service) priority (experimental) and ECN

(Explicit Congestion Notification).


A 1-bit bottom of stack flag. If this is set, it signifies that the current label is the last
in the stack.



An 8-bit TTL (time to live) field.

These MPLS-labelled packets are switched after a label lookup/switch instead of a lookup
into the IP table. As mentioned above, when MPLS was conceived, label lookup and label
switching were faster than a routing table or RIB (Routing Information Base) lookup because
they could take place directly within the switched fabric and not the CPU.
Routers that perform routing based only on the label are called label switch routers (LSRs).
The entry and exit points of an MPLS network are called label edge routers (LERs), which,
respectively, push an MPLS label onto an incoming packetand pop it off the outgoing packet.
Alternatively, under penultimate hop popping this function may instead be performed by
the LSR directly connected to the LER. MPLS technology has two routers- code router and
edge router. The format of the information provided by the router is-

Device ID

Local Interface

Hold time

Capability

Platform

Port ID

DATA CENTRE OF BILLING
It consists of databases for storing data.A data centre or computer centre is a facility used to
house computer systems and associated components, such as telecommunications and
storage systems. It generally includes redundant or backup power supplies, redundant data
communications connections, environmental controls (e.g., air conditioning, fire
suppression) and security devices. Large data centres are industrial scale operations using as
much electricity as a small townand sometimes are a significant source of air pollution in the
form of diesel exhaust. The Data Centres are always placed on a large raised platform.
Below the platform air conditioning is provided to prevent the equipments from getting
damaged owing to high temperature. The main data centre of BSNL WEST is located in
Pune, which houses a large database of the subscribers of the entire WEST Zone. The
backup of the data centre resides in the MSC Saket Nagar, Bhopal, which in case of any fault
occurred in the main data centre of Pune, will automatically take the entire database so that
it may not be lost. Data Centre uses the servers of ‘hp’.
A data centre keeps high standards for assuring the integrity and functionality of its hosted
computer environment. This is accomplished through redundancy of both fibre optic cables
and power, which includes emergency backup power generation. The Telecommunications
Industry Association's TIA-942 Telecommunications Infrastructure Standard for Data
Centres, specifies the minimum requirements for telecommunications infrastructure of data
centres and computer rooms including single tenant enterprise data centres and multitenant Internet hosting data centres.

Racks of Telecommunications equipments as part of Data Centre

Effective data centre operation requires a balanced investment in both the facility and the
housed equipment. The first step is to establish a baseline facility environment suitable for
equipment installation. Standardization and modularity can yield savings and efficiencies in
the design and construction of telecommunications data centres. Standardization means
integrated building and equipment engineering. Modularity has the benefits of scalability
and easier growth, even when planning forecasts are less than optimal. For these reasons,
telecommunications data centres should be planned in repetitive building blocks of
equipment, and associated power and support (conditioning) equipment when practical.
The "lights-out" data centre, also known as a darkened or a dark data centre, is a data
centre that, ideally, has all but eliminated the need for direct access by personnel, except
under extraordinary circumstances. Because of the lack of need for staff to enter the data
centre, it can be operated without lighting. All of the devices are accessed and managed by
remote systems, with automation programs used to perform unattended operations. In
addition to the energy savings, reduction in staffing costs and the ability to locate the site
further from population centres, implementing a lights-out data centre reduces the threat
of malicious attacks upon the infrastructure.
A data centre can occupy one room of a building, one or more floors, or an entire building.
Most of the equipment is often in the form of servers mounted in 19 inch rack cabinets,
which are usually placed in single rows forming corridors (so-called aisles) between them.
This allows people access to the front and rear of each cabinet. Servers differ greatly in size
from 1U servers to large freestanding storage silos which occupy many square feet of floor
space. Some equipment such as mainframe computers and storage devices are often as big
as the racks themselves, and are placed alongside them. Very large data centres may
use shipping containers packed with 1,000 or more servers each;when repairs or upgrades
are needed, whole containers are replaced (rather than repairing individual servers). Local
building codes may govern the minimum ceiling heights.The physical environment of a data
centre is rigorously controlled. Air conditioning is used to control the temperature and
humidity in the data centre. ASHRAE's "Thermal Guidelines for Data Processing
Environments"recommends a temperature range of 16–24 °C (61–75 °F) and humidity range
of 40–55% with a maximum dew point of 15 °C as optimal for data centre conditions. The
temperature in a data centre will naturally rise because the electrical power used heats the
air.
Unless the heat is removed, the ambient temperature will rise, resulting in electronic
equipment malfunction. By controlling the air temperature, the server components at the
board level are kept within the manufacturer's specified temperature/humidity range. Air
conditioning systems help control humidity by cooling the return space air below the dew.
Too much humidity and water may begin to condense on internal components. In case of a

dry atmosphere, ancillary humidification systems may add water vapour if the humidity is
too low, which can result in static electricity discharge problems which may damage
components. Subterranean data centres may keep computer equipment cool while
expending less energy than conventional designs.To prevent single points of failure, all
elements of the electrical systems, including backup systems, are typically fully duplicated,
and critical servers are connected to both the "A-side" and "B-side" power feeds. Data
centres typically have raised flooringmade up of 60 cm (2 ft) removable square tiles. The
trend is towards 80–100 cm (31–39 in) void to cater for better and uniform air distribution.
These provide a plenum for air to circulate below the floor, as part of the air conditioning
system, as well as providing space for power cabling.

A back up of batteries in a data centre providing power until diesel generators can start

BILLING-The billing centre is responsible for processing the toll tickets generated by the
VLRs and HLRs and generating a bill for each subscriber. It is also responsible for generating
billing data of roaming subscriber. It is a part of NSS (Network and Switching Subsystem).
Dotsoft is in-house developed software, integrating software, integrating the Commercial
Activities, Telecom Billing& Accounting, FRS and Directory Enquiry. It has been implemented
in 171 SSAs across the country. All the SSAs of Andhra Pradesh, Tamil Nadu, Karnataka,
Assam, Punjab, Chhattisgarh and Gujarat Circles have implemented it. Rest of SSAs are from
Maharashtra, Madhya Pradesh, Uttar Pradesh, Rajasthan, J&K and Haryana. Dotsoft is
transferred to IT Project Circle from AP Circle from July 2007 onwards.Dotsoft package was
initially implemented at Guntur in 1997 making it the first
Telecom District in BSNL to have an integrated customer care and billing
Software.
• Dotsoft is integrated with other systems such as call centre, BSNL portal
(www.bsnl.in). BSNL portal enables online bill payments and availability of
Duplicate bills for its customers.
• In addition, Dotsoft, AP has a tie-up with e-seva, the most popular e-governance
Project of Andhra Pradesh government.
• BSNL portal - www.bsnl.in, provides customers with a complete online delivery,
review and payment solution all at a single mouse click.
• It has been conceptualized, designed and developed entirely by the core group of
the Software Development Centre at Hyderabad of IT project Circle, Pune.
• Dotsoft is implemented in Computer Network in Client / Server mode.

• Now a day’s Central server concept is used in Dotsoft wherein a single server will
be available for 13 to 15 SSA’a in a Circle.There is a Dotsoft server available
at Nagpur , Aurangabad & Pune covering Maharashtra Circle..
Important features /utility /advantage of dotsoft
• Every subscriber is identified by a unique identification number called
Unique_Id_No
• Bill generation is absolutely easy and totally secure.
• Payments are faster and completely hassle free for the customer and the counter
personnel because of the use of bill scanners.
• Online enquiry is available for supervision and queries
• All the work is done online which results in excellent customer service, nonduplication
of work, total supervision, complete transparency, better planning.
• Complete history of subscriber’s activities available online.

• Outstanding details can be taken for any month on any given date.
• Directory Enquiry shows the status at the moment of enquiry. It can query on any of the
subscriber’s details.
Some Circles like MP circle have adopted SSANet DQ system integrated with Trichur
billing system. The Billing and Customer Care Subsystem [BCCS] of BSNL has been sourced
from CSGSystems, and is referred to as the Kenan BP/OM or Arbor. This is a powerful
platform forbilling and customer care, and can be configured to suit organizational and
customerneeds.This application is client-server based where the data or information is
contained in oneor more centralized database on servers and the user interfaces reside in
the workstation.The application can be used in a local area network (LAN) environment or
WANNetworkBCCS BSNL Billing Zones
In BSNL there is four Billing zones namely BSNL West, BSNL East, BSNL South, and
BSNL North. For BSNL west Zone the billing centre is at Pune.
INTELLIGENT NETWORK
The Intelligent Network (IN) is the standard network architecture specified in the ITU-T
Q.1200 series recommendations. It is intended for fixed as well as mobile telecom networks.
It allows operators to differentiate themselves by providing value-added services in addition
to the standard telecom services such as PSTN, ISDN and GSM services on mobile phones.
The intelligence is provided by network nodes on the service layer, distinct from
theswitching layer of the core network, as opposed to solutions based on intelligence in the
core switches or telephone equipment. The IN nodes are typically owned
bytelecommunications operators (telecommunications service providers).IN is supported by
the Signalling System #7 (SS7) protocol between telephone network switching centres and
other network nodes owned by network operators. Services provided by IN are


Televoting
Call screening





















Telephone number portability
Toll free calls/Free phone
Prepaid calling
Account card calling
Virtual private networks (such as family group calling)
Centrex service (Virtual PBX)
Private-number plans (with numbers remaining unpublished in directories)
Universal Personal Telecommunication service (a universal personal telephone number)
Mass-calling service
Prefix free dialling from cell phones abroad
Seamless MMS message access from abroad.
Reverse charging
Home Area Discount
Call distribution based on various criteria associated with the call
Location Based Routing
Time-based routing
Proportional call distribution (such as between two or more call centres or offices).
Call queuing
Call transfer

The initial use of IN technology was for number translation services, e.g. when translating
toll free numbers to regular PSTN numbers. But much more complex services have since

been built on IN, such as Custom Local Area Signalling Services (CLASS) and prepaid
telephone calls. The Intelligent Network of BSNL WEST is located in Pune.
PREPAID CONNECTIONS
A prepaid mobile connection is a facility for which credit is purchased in advance of service
use. The purchased credit is used to pay formobile phone services at the point the service is
accessed or consumed. If there is no available credit then access to the requested service is
denied by the mobile phone network. Users are able to top up their credit at any time using
a variety of payment mechanisms. A prepaid mobile phone has access to most if not all of
the services offered by amobile phone operator, although the charges for these services
may differ from customers with the same operator who have a postpaid contract.
In addition, a prepaid phone has a balance which can be queried at any time, and also
topped up periodically. Examples of ways in which the balance can be topped up are the
following:




A credit card or debit card
Direct from a bank account using an ATM
In a retail store by purchasing a "top-up" or "refill" card at retail. These cards are
stamped with a unique code (often under a scratch-off panel) which must be entered
into the phone in order to add the credit onto the balance.







In a retail store using a swipe card where the balance is credited automatically to the
phone after the retailer accepts payment.
From other mobile phones on certain networks which provide international top-up
services, where the initiator of the top up is often a migrant worker wanting to add
minutes to the prepaid mobile phone of a family member back home.
Direct from some open-loop prepaid cards featuring a mobile refill service.
Through electronic reloading where a specially designed SIM card (Retailer's SIM card as
used to define in the Philippines and India) is used to reload a mobile phone by entering
the mobile number and choosing the amount to be loaded. This process is widely
implemented in the Philippines and India so that any person can be a prepaid load
retailer creating a nationwide availability of reloading stations, even in remote areas. To
free up resources on the network for new customers, an operator will periodically
delete prepaid SIM cards which have not been used for some time, at which point their
service (and its associated phone number) is discontinued. The rules for when this
deletion happens vary from operator to operator
POST PAID CONNECTIONS

The post-paid connection is a facility for which service is provided by a prior arrangement
with a carriage service provider (CSP). The user in this situation is billed after the fact
according to their use of mobile services at the end of each month. Typically, the customer's
contract specifies a limit or "allowance" of minutes, text messages etc., and the customer
will be billed at a flat rate for any usage equal to or less than that allowance. Any usage

above that limit incurs extra charges. Theoretically, a user in this situation has no limit on
use of mobile services and, as a consequence, unlimited credit. This service is better for
people with a secured income.
Postpaid service mobile phone typically requires two essential components in order to make
the 'post-usage' model viable:



Credit history/Contractual commitment: This is the basis on which the service
provider is able to trust the customer with paying their bill when it’s due and to
have legal resource in case of non-payment
Service tenure: Most post paid providers require customers to sign long term (13 year) contracts committing to use of the service. Failure to complete the term
would make the customer liable for early termination fees.

The bill itself is an important component of the services which acts as an ambassador of the
service provider and at times as an evidence of the service itself. The bill needs to be
readable; comprehensible as well as aesthetically attractive for the subscriber to be
interested enough to see details other than the bill amount.
When a call through a pre paid mobile phone is made, the call is first routed to Intelligent
Network (IN) and then to HLR, while in case of a post paid mobile phone, the call is routed
directly to HLR.
BSNL CUSTOMER CARE CENTRE

Several Steps have been taken at BSNL to augment the quality of customer care to
international standards.
 Access round the clock help at following toll free numbers
1. Dataone Broadband '1600-424-1600'
2. PSTN Call Centre '1500' (in select states)
3. Sancharnet Help Desk '1957'
4. Cell One all India Help '9400024365'
 All BSNL Customer Service Centres (CSCs) now remain open on all seven days from 8.00
AM to 8.00 PM without any break for all activities.



Cheque deposit machines have also been installed in many cities, so that customers can
make payments 24X7 at their convenience.
 Customers can also make payments by cheque/Demand Draft to BSNL franchisees all
over the country.
 Establishing call centres across the nation to provide single window solutions and
convenience to customers.
Customer Care Centre caters to the requests and complaints lodged by the subscribers. A
Customer Care Centre works in four domainsRequests- Subscribers can make following requests to the centre Block SIM Card, in case of loss of mobile phone
 Deactivate Value Added Services (VAS)
 Shift telephone
Queries-Customers can seek information regarding new plans, vouchers and services
provided by BSNL, Mobile Number Portability from Call Centres.
Complaints-Customers can lodge complaints to the Call Centres regarding Billing problem
 Network problem
 Unwanted balance deduction
 Call drop
 No Internet Connectivity
Facilities-Facility of Value Added Services (VASs) is provided by call centres.
Call Centres too hold the data bases of the customers and maintain their call detail
records. When a customer takes a connection in BSNL, he has to submit his documents to
the retailer. This information is received and stored in HLR, but the services do not start
except one toll free number. The Customer Care verifies the information given by the
customer and after getting matched provides the connection and services to the customer.
BSNL provides following toll free numbers for catering the customersFor GSM Pre paid customers- 1503
For GSM Post paid- 1502
For 3GC- Top up- 1501
For tele verification- 1507
For Blackberry customers- 1505

For contacting BSNL Customer Care Centre from the number of any other operator,
1800180 has to be dialled before any of the above numbers.
Canon FX- It is the software for prepaid, post paid orders
IN- It is used for billing of Pre paid numbers (It contains one day data)
CDR- It stands for Call Detail Record. It holds the data of 15 days.
Sanchar Soft- This service is used for activating new number, tele verification, etc.
Value Added Services in BSNLThe Value Added Services are available through the STK (SIM TOOL KIT) Menu option and
through the short codes. The STK services form part of the Menu, which you can browse on
your handset. Such VASs are listed as SERVICES in the Menu. The detailed service portfolio
under
STK
is
as
under:
1
List
of
services
for
STK
with
16K
SIM
card
2
List of services for STK with 32K SIM card
The
easy
way
to
go
about
availing
the
above
services
is:
(a) Browse the Menu on your CELLONE to see the SERVICES menu.
(b) Browse the Menu further down to select the service as per above details to select the
option as per the service you want to avail and press "Send/yes" depending upon your
handset to avail that service.In addition, BSNL also has signed agreements with
various companies for providing VAS to its GSM mobile subscribers, these are:
Code
8888
6678
9090
7333
6388
2424
4545
---@
5050

Franchisee
IndiaTimes
COMPUCOM
SAHARA
REDIFF.com
NDTV
Aajtak
Sify
Pti
Bharat matrimony

Zones
Agreement Term :1 yr
All four
Nov-Dec ‘02
North only April'03
All four
Aug'03
- do Sept'03
- do Oct 03
- do Nov'03#
- do Nov'03#
- do Nov'03
- do Nov'03#

# Services are being activated in BSNL's SMSCs.
@ Short code yet to be allotted
The procedure to avail these services is different from that in STK based services, as in case
of STK based services there is no need to input any SHORT CODE or any TEXT message.
The procedure for availing short code based VAS is as follows:
a) Browse the menu in your cell phone, select MESSAGE & then go to WRITE /SEND NEW
(Menu may vary with the handset).
b) Enter the keyword applicable to the service you want to avail

c) Proceed further by pressing "Yes" and enter the applicable short code as the NUMBER.
E.g. if you want to get the NEWS from AAJTAK then the short code will be "2424".
e) After entering the short code, use "Send"/ "Yes",for sending the SMS to the SMSC.
After a short time, you will get the response SMS in your INBOX.
MOBILE NUMBER PORTABILITY
Mobile number portability (MNP) enables mobile telephone users to retain their
mobile telephone numbers when changing from one mobile network operator to another.
MNP (Mobile number portability) is implemented in different ways across the globe. The
International and European standard is for a customer wishing to port his/her number to
contact the new network (Recipient), which then sends the number portability request
(NPR) to the current network (Donor). This is known as 'Recipient-Led' porting.
The UK & India are the only exceptions to implement the Donor-Led system. The customer
wishing to port his/her number is required to contact the Donor to obtain a Porting
Authorisation Code (PAC), which is then showed to the recipient network to proceed. Once
having received the PAC the Recipient continues the port process by contacting the Donor.
This form of porting is known as 'Donor-Led' and has been criticised by some industry
analysts as being inefficient, though prevents MNP scams. It has also been observed that it
may act as a customer deterrent as well as allowing the Donor an opportunity of 'winningback' the customer. This might lead to distortion of competition, especially in the markets
with new entrants that are yet to achieve scalability of operation. A significant technical
aspect of MNP is related to the routing of calls or mobile messages (SMS, MMS) to a number
once it has been ported. There are various flavours of call routing implementation across
the globe. For India, the details of the porting operation is given asImplementation Date
20.01.2011

Time to port
7 days

Price
Rs. 19

Procedure
Customers can port
between prepaid and
postpaid options.
The master database
will be managed by a
third party firm. For
zone I, Syniverse has
been appointed with
the MNP and related
issues while for zone
II, it isTelcordia. The
customer should
have completed a
period of 90 days
(from the date of
activation of the
mobile connection)
with the current
operator, to be

eligible for porting to
another operator.
To shift your mobile
number from one
operator to another,
a customer shall
send PORT <your
Mobile Number> to
1900. You will
receive a unique
alphanumeric UPC
(Unique Porting
Code) as a SMS from
1901 giving 8 digit
alphanumeric
Unique Porting Code
(UPC) and UPC expiry
date in MM/DD/YYYY
format. Visit the
office of your new
mobile operator and
give them this UPC
Code.

Mobile communication - GSM/CDMA/WIMAX Technologies

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