report on communication medium in modern tv

120970107021 Communication mediums in modern TV
Abstract
No other electronic media has created as much mass impact as the TV.TV is both a personal as well as
family/community device which makes it reach a large population. Obviously the immense popularity of TV
has resulted in an unprecedented growth of TV viewing as well as technology. From the simple TV, today one
can have a smart TV with varying features satisfying all sections of society. Not only have the TV signals
been converted from analog to digital, today one has high definition TV, the IPTV, the dbs TV available. This
gives an overview of the communication mediums in modern TV
With the development in compression techniques and bandwidth efficient modulation techniques digital
transmission has become a reality. Digital TV has removed the line of distinction between the computer and
TV and merged TV and computing because of the digital representation of image and video. Digital TV also
called as Direct Broadcast Satellite (DBS) TV and Direct to Home (DTH) TV. It is broadcasted using satellite
system, where before transmission the signals which may originate from various sources are converted to
digital, compressed, time division multiplexed and modulated before transmitting on uplink to the satellite
transponder. The receiver unit at home of the user has an important device called Digital Set top box which
provides the user the access to various digital content.
IPTV or Internet Protocol Television is a scheme that uses IP networking protocol to transport data. IPTV
differs from terrestrial broadcasting TV as IPTV is interactive that is two way user sends his requests and
based on that receives the services whereas terrestrial broadcasting TV is one way. Management in Terrestrial
broadcasting TV is almost nil whereas IPTV is fully managed including the billing, also the streaming in
terrestrial TV systems is simultaneous whereas in IPTV systems it is in bundles.
Marwadi Education Foundation i

Acknowledgment
It is needed a great pleasure to express my thanks and gratitude to all those who helped me. No serious and
lasting achievement or success, one can ever achieve without the help of friendly guidance and cooperation of
so many people involved in the report.
I am very thankful to my guide Prof. Hemang Kothari, the person who makes me to follow the right steps
during a seminar work. I express my deep sense of gratitude to for his guidance, suggestions and expertise at
every stage. Apart from that his valuable and expertise suggestion during documentation of my report indeed
help me a lot.
Thanks to my friend and colleague who have been a source of inspiration and motivation that helped to me
during my seminar work. I would heartily thankful to head of our computer department Prof. Jay Teraiya to
give me an opportunity to work over this topic and for their endless and great support. And to all other people
who directly or indirectly supported and help me to fulfill my task.
And at last but not least, I would be grateful towards my parents and friends who had supported a lot and
provided inspiration and motivation to go in this area.
HARSH MEHTA
120970107021
Marwadi Education Foundation ii

Table of Contents
Abstract.............................................................................................................................................................. i
Acknowledgment............................................................................................................................................... ii
List of Figure ......................................................................................................................................................iv
Chapter 1: INTRODUCTION ..................................................................................................................................1
Chapter 2: DIRECT BROADCAST SATELLITE ............................................................................................................2
2.1 What is dbs? ..................................................................................................................................................2
2.2 Components involved in dbs...........................................................................................................................3
2.3 Application ....................................................................................................................................................4
Chapter 3: MULTIPLE ACCESS ...............................................................................................................................5
3.1 FDMA............................................................................................................................................................5
3.2 TDMA............................................................................................................................................................5
3.3 Advantages of TDMA over FDMA: ...................................................................................................................5
3.4 Dama ............................................................................................................................................................6
Chapter 4: VIDEO COMPRESSION .........................................................................................................................8
4.1 MPEG ............................................................................................................................................................8
4.2 MPEG-1 .........................................................................................................................................................8
4.3 MPEG-2 .........................................................................................................................................................8
4.4 MPEG-4 .........................................................................................................................................................8
4.5 Mpeg-2 Video Compression............................................................................................................................8
Chapter 5: IPTV ................................................................................................................................................. 10
5.1 Triple Play Service ........................................................................................................................................ 10
5.2 Triple Play Setup Using ADSL Modem And Splitter ......................................................................................... 10
5.3 Features Does IPTV Offer.............................................................................................................................. 12
5.4 Advantages Of Iptv....................................................................................................................................... 15
5.5 Disadvantages Of Iptv.................................................................................................................................. 15
5.6 Future of Iptv............................................................................................................................................... 15
Marwadi Education Foundation iii

List of Figure
Figure 2.1 Direct broadcast satellites............................................................................................................... 2
Figure 2.2 Components involved in dbs .......................................................................................................... 3
Figure 3.4 Direct broadcast satellite television................................................................................................ 7
Figure 4.5 Mpeg-2 frames ............................................................................................................................... 9
Figure 5.0 Iptv ............................................................................................................................................... 10
Figure 5.2 Triple play setup using ADSL modem and splitter ...................................................................... 11
Figure 5.3 Feature of iptv .............................................................................................................................. 14
Figure 5.6 Future of iptv ................................................................................................................................ 16
List of
Marwadi Education Foundation iv

Chapter 1: INTRODUCTION
Direct broadcast satellite (DBS) and has experienced continual growth in capacity since its beginnings. Its
growth has been enabled by several core technologies, the capabilities of which increase over time. This
looks at DBS services in the globe, examines how system capacity has changed over time, and looks at how
some core technologies will likely evolve. It is found that there is no technical barrier to further capacity
increases being implemented over time in the services.
Video compression uses digital technology to reduce the number of bits needed to send a video program. The
more efficient the video compression technology, the fewer bits needed for each channel, and the more
channels that can be sent using a satellite transponder’s fixed bandwidth. Alternatively, more efficient video
compression allows the same bit rate to be used to send higher-resolution video.
IPTV describes a system capable of receiving and displaying a video stream encoded as a series of Internet
Protocol packets. If you've ever watched a video clip on your computer, you've used an IPTV system in its
broadest sense. Once known only as phone companies, they now want to turn a "triple play" of voice, data,
and video that will retire the side and put them securely in the batter's box. In this explain how IPTV works
and what the future holds for the technology. Though IP can (and will) be used to deliver video over all sorts
of networks.
Marwadi Education Foundation 1

Chapter 2: DIRECT BROADCAST SATELLITE
2.1 What is dbs?
DBS Satellite used to deliver TV programs to viewers all over the world; Ex “Nile-Sat”.The signals used by
broadcast TV satellites are typically digitally compressed. The provider selects programs and broadcasts
them to subscribers as a set package. DBS technology enables consumers to receive digitally modulated
television signals directly from satellites.
Figure 2.1 Direct broadcast satellites
Direct Broadcast Satellite is a communication link that transmits directly from the transmitter to the user. The
end user receives data from a high frequency satellite in geosynchronous orbit (GEO). The high power of
transmission from this satellite allows the user's receiving dish to be the size very small. By using video
compression and encoding in the transmission, hundreds of channels can be broadcast over the bandwidth
available.

2.2 Components involved in dbs
Figure 2.2 Components Involved In Dbs
Programming sources are simply the channels that provide programming for broadcast. The provider doesn't
create original programming itself. It pays other companies for the right to broadcast their content via
satellite. The broadcast center is the central hub of the system. At the broadcast center, the TV provider
receives signals from various programming sources and beams a broadcast signal to satellites in
geosynchronous orbit. The satellites receive the signals from the broadcast station and rebroadcast them to
Earth. The viewer's dish picks up the signal from the satellite and passes it on to the receiver in the viewer's
house. The receiver processes the signal and passes it on to a standard TV.

2.3 Application
 Subscription based TV
 Pay per view
 Digital video records
 Interactive services

Chapter 3: MULTIPLE ACCESS
3.1 FDMA
Frequency division multiple access, as the name suggests, operates by dividing the available bandwidth
between users on the basis of frequency. A group of users may be allotted a range of frequencies and each
individual user can use a limited frequency shifted channels, within that range. Earlier analogue FDMA used
FM waves with slightly different carrier frequencies to get the job done.
A method allowing multiple carriers to share a single satellite transponder or range of frequencies. The
transponder bandwidth is divided into sub-channels, each of which is allocated to a particular earth station
(carrier).The earth stations transmit continuously and the transponder conveys several carriers simultaneously
at different frequencies
FDMA can be performed in two ways:
 Fixed-assignment multiple access (FAMA): The sub-channel assignments are of a fixed allotment.
Ideal for broadcast satellite communication.
 Demand-assignment multiple access (DAMA): The sub-channel allotment changes based on demand.
Ideal for point to point communication.
3.2 TDMA
In TDMA, ideally, the whole bandwidth is used by a user for a fixed amount of time. All practical TDMA
signals are digital and hence are advantageous over traditional FDMA system. Problems of non-linearity are
not present here as at a time the whole bandwidth of a transponder is used only by a single .However, need
for higher bit rates (requires more energy) and presence of ISI can be a problem.
In Time Division Multiple Access (TDMA), it makes use of the same frequency spectrum but allows more
users on the same band of frequencies by dividing the time into “slots” and shares the channel between users
by assigning them different time slots.TDMA is utilized by Digital-Advanced Mobile Phone System (D-AMPS)
and Global System for Mobile communications (GSM).
However, each of these systems implements TDMA in a somewhat different and incompatible way.
3.3 Advantages of TDMA over FDMA:
 Digital equipment used in time division multiplexing is increasingly becoming cheaper.
 There are advantages in digital transmission techniques. Ex: error correction

 No need for precise narrowband filters.
 Easy for mobile or base stations to initiate.
 The most cost-effective technology for upgrading a current analog system to digital.
3.4 Dama
This technique is used when the link between the station and satellite is not a constant one. This helps assign
bandwidth according to demand. This can be implemented on TDMA or as a combination with FDMA and
TDMA.
DAMA is often used in military environments due to the relative simplicity of implementation and ease of
modelling. It can operate with bent pipe transponders and thus require no security on the satellite side. The
master and slave stations can upgrade compressions without expensive satellite replacements.Set of sub
channels in a channel is treated as a pool of available links .For full-duplex between two earth stations, a pair
of sub channels is dynamically assigned on demand.Demand assignment performed in a distributed fashion
by earth station using CSC.

Figure 3.4 Direct Broadcast Satellite Television

Chapter 4: VIDEO COMPRESSION
4.1 MPEG
MPEG stands for Moving Picture Coding Exports Group. At the same time it describes a whole family Of
international standards for the compression of audio-visual digital data. The most known are MPEG-1,
MPEG-2 and MPEG-4, which are also formally known as ISO/IEC-11172, ISO/IEC-13818 and ISO/IEC-
14496.
4.2 MPEG-1
Allowed to play a video in real time from a 1x CD-ROM. The frame rate in MPEG-1 is locked at 25 (PAL)
fps and 30 (NTSC) fps respectively. Further MPEG-1 was designed to allow a fast forward and backward
search and a synchronisation of audio and video. A stable behaviour, in cases of data loss, as well as low
computation times for encoding and decoding was reached, which is important for symmetric applications,
like video telephony.
4.3 MPEG-2
Which allowed a higher quality with a slightly higher bandwidth? MPEG-2 is compatible to MPEG-1. Later
it was also used for High Definition Television (HDTV) and DVD, which made the MPEG-3 standard
disappear completely. The frame rate is locked at 25 (PAL) fps and 30 (NTSC) fps respectively, just as in
MPEG-1. MPEG-2 is more scalable than MPEG-1 and is able to play the same video in different resolutions
and frame rates.
4.4 MPEG-4
It provided lower bit rates (10Kb/s to 1Mb/s) with a good quality. It was a major development from MPEG-
2 and was designed for the use in interactive environments, such as multimedia applications and video
communication. It enhances the MPEG family with tools to lower the bit-rate individually for certain
applications. It is therefore more adaptive to the specific area of the video usage.
4.5 Mpeg-2 Video Compression
Video and Audio, and sometimes Data elements are encoded into a sequence of frames. A frame is a single
image from a video or audio sequence. In most countries, one frame occurs every 33 milliseconds. Each
frame is encoded in one of three ways:
1. I – Frame
 Compressed directly from a raw (uncompressed) frame.

 Compression is based in the current raw frame only and inability of human eye to detect certain
changes in the image.
 I-frame is a reference frame and can be used to predict the P-frame immediately following it
2. P – Frame
 Compression is based on spatial redundancy (pixels) as well as on time based redundancy (frame).
 P-frame can be predicted by referring I-frame or P-frame immediately preceding it.
3. B - Frame
 Compression is similar to P-frame except that B-frame compression is done by referring previous as
well as I-frame and P-frame
Figure 4.5 Mpeg-2 Frames

Chapter 5: IPTV
IPTV stands for Internet Protocol Television. It is a digital television services that receives both TV or
multimedia services via Internet connection. IPTV will provide better quality of service than Internet
streaming video.IPTV has the potential to offer an interactive, customized experience.
Figure 5.0 Iptv
5.1 Triple Play Service
Triple Play service is a complete package that allows customers to watch TV, browse the internet and making
a long distance calls using the VoIP. This service is typically provided by a service provider using a closed
network infrastructure. Triple play services require a network that is scalable to deliver these services to the
mass market; reliable, to provide the optimal quality of experience for the subscriber; and flexible, to adapt to
service changes and new service opportunities.
5.2 Triple Play Setup Using ADSL Modem And Splitter
Broadband is an ‘always-on’ high speed internet service. The Broadband service “Triple Play” i.e. Voice,
Video and Data services all possible simultaneously on the same copper telephone line. MTNL is currently
offering Internet Services starting from 256 kbps going up to 2 Mbps. For extending these services the
telephone cable coming to the subscriber’s premises is connected to a Broadband Modem (ADSL2+ modem)
using a POTS Splitter. The Broadband Modem acts as an interface between telephone cable and computer.
The “POTS Splitter” is used to separate voice and data signals enabling both Voice and Internet

simultaneously on the same telephone line. One cable out of POTS Splitter is connected to the telephone
instrument.
Figure 5.2 Triple Play Setup Using ADSL Modem And Splitter
Broadband is an ‘always-on’ high speed internet service. The Broadband service “Triple Play” i.e. Voice,
Video and Data services all possible simultaneously on the same copper telephone line. MTNL is currently
offering Internet Services starting from 256 kbps going up to 2 Mbps. For extending these services the
telephone cable coming to the subscriber’s premises is connected to a Broadband Modem (ADSL2+ modem)
using a POTS Splitter. The Broadband Modem acts as an interface between telephone cable and computer.
The “POTS Splitter” is used to separate voice and data signals enabling both Voice and Internet
simultaneously on the same telephone line. One cable out of POTS Splitter is connected to the telephone
instrument.

The POT's splitter should be placed at a suitable point before any other device is connected to the telephone
line. This is important for proper working of the Broadband connection. The POT's splitter has three ports
which are to be connected as below –
 Line port – for connecting the telephone line from exchange.
 Phone port – for connecting the telephone instrument.
 DSL port for connecting the Broadband modem.
The interfaces are to be connected as follows –
 ADSL interface (RJ 11) for connecting the incoming DSL line from the POTS splitter.
 Ethernet interface (RJ45) for connecting the Ethernet cable from the PC.
 USB interface for connecting the USB cable from the PC.
5.3 Features Does IPTV Offer
1. Broadcast type
 Pay TV
 Electronic Programmed Guide (EPG)
 Live Streaming for VOD
 Progressive Downloads(Video, gaming, music downloads)
2. Interactive type
 Interactive TV
 Video Conferencing
 Interactive Online Network Gaming
 Interactive E-Learning
3. On Demand type
 Interactive VOD(video on demand)
 Client side Personal Video Recording
 Pay per View(PPV)
 Time Shifted TV

4. Internet and Voice types
 VoIP
 Browsing on TV
 E-mail/SMS/MMS from TV
 Caller ID Popup

Figure 5.3 Features of Iptv

5.4 Advantages Of Iptv
Other than wireless communication, another advantage of IPTV is that if the customer has quadruple play
(internet television, telephone, mobile phone service) with the same company, the cell phone can be used to
schedule the recording of a program. Excluding cell phone service and having only three services with a
company is referred to as triple play
5.5 Disadvantages Of Iptv
There are some limitations to IPTV. According to Wikipedia, because IPTV is based on the Internet Protocol,
it is sensitive to packet loss and delays if the IPTV connection is not fast enough and it also does not support
HDTV at the moment. AT&T is currently experimenting with HDTV and its U-Verse service in the Houston
area according to Cable Industry Insider.
5.6 Future of Iptv
IPTV is much different than the digital video accessed by millions of users on YouTube or other video
streaming websites, but it shares a lot of the same ubiquitous, pervasive nature. A single subscription can be
accessed by multiple television sets within a home, and Internet-based transmission allows for web-based
applications to enhance a viewer’s experience. Our goal today is to explore the the current state of IPTV and
Internet television technologies globally, as well as what the near future holds for these entertainment
systems.
With these new companies in the mix, competition for television subscribers will likely heat up in the coming
years. Companies’ currently offering web and television services could likely be enticed to open up their
regional basis and begin competing for customers across the country. Telecom companies that develop their
own IPTV services may be able to keep the complete price of their Internet and television bundle down the
most, but unless they offer both a wide selection and large degree of customization, but Internet-based
streaming services like Netflix, Hulu+ and Amazon Prime already enjoy a great number of customers without
providing Internet.

Figure 5.6 Future Of Iptv
The idea of the “second screen” is a recent concept growing quickly due to the development of IPTV
technologies. Customers will likely begin accessing broadcasted content through tablets and other Internet-connected
mobile electronic devices. These services will allow users to access video-on-demand and other
broadcast services through a device while outside of the home.

References:
1. Timothy Pratt, Charles bostian and Jeremy allnut, “satellite communications", john Wiley & sons, Inc.,
second edition, 2006.
2. http://en.wikipedia.org/wiki/direct-broadcast_satellite
3. http://www.maplenet.net/~trowbridge/dbsintro.htm
4. http://www.bretl.com/mpeghtml/mpegindex.htm
5. Directbroadcastsatellitetv-090723111626-phpapp02.slideshare
6. Directbroadcastsatellitetv-090723111626-phpapp02.slideshare
7. Iptv-121106124704-phpapp02.pptx.slideshare
8. Tiberius Artzi, “direct satellite communication", us patent no.6553009, issued on April 22, 2003.

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