This document summarizes two modern communication mediums: Direct Broadcast Satellite (DBS) television and Internet Protocol Television (IP-TV). It describes how DBS uses satellites to deliver digitally compressed TV programs to viewers worldwide. It also explains the components of a DBS system, including programming sources, broadcast centers, satellites, dishes, and receivers. For IP-TV, it defines it as digital television services delivered via internet and outlines the technologies used like broadband and digital subscriber lines. It provides examples of content and services offered by IP-TV like video on demand, interactive TV, and voice calls.

1. Communication mediums in
modern TV
PRESENTED BY,
HARSH MEHTA

2. 1)Direct Broadcast Satellite TV(DBS -TV)
2)Internet Protocol Television(IP -TV)

3. References:
• Timothy Pratt, Charles Bostian and Jeremy Allnut,
“Satellite Communications", John Wiley & Sons,Inc,Second Edition,2006.
• http://en.wikipedia.org/wiki/Direct-broadcast_satellite
• http://www.maplenet.net/~trowbridge/DBSintro.htm
• http://www.bretl.com/mpeghtml/MPEGindex.htm

4. • directbroadcastsatellitetv-090723111626-phpapp02.slideshare
• HiSeasNet Training Courses, August 2009.doc
• iptv-121106124704-phpapp02.pptx.slideshare
• Tiberius Artzi, ”Direct Satellite Communication", US Patent
No.6553009,Issued on April 22,2003.

5. 1)Direct Broadcast Satellite(DBS) television

6. DBS Television

7. Overview of the 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.

8. • This is a large GEO DBS TV Satellite.

9. Need of Multiple Access
• Satellites are usually built and employed for the common good of one or more
regions.
• For this purpose, one of the several multiple access techniques, Mentioned
are FDMA, TDMA and DAMA.

10. FDMA
• Satellite frequency is already broken into bands, and is broken in to smaller
channels in Frequency Division Multiple Access (FDMA).
• Overall bandwidth within a frequency band is increased due to frequency
reuse.
• The number of sub-channels is limited by three factors:
1. Thermal noise (a signal will be effected by background noise).
2. Intermodulation noise ( a signal will cause noise).
3. Crosstalk (cause by excessive frequency reusing).

11. 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 .

12. TDMA
• TDMA (Time Division Multiple Access) breaks a transmission into multiple time
slots, each one dedicated to a different transmitter.
• TDMA is increasingly becoming more widespread in satellite communication.
• TDMA uses the same techniques (FAMA and DAMA) as FDMA does.

13. 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.

14. Demand Assigned Multiple Access (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.

15. Components involved in a DBS system

16. • 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.

17. Application
• Subscription-based TV
• Pay per-view (PPV)
• Digital video recorders (DVR)
• Interactive services

18. VIDEO COMPRESSION BASICS
(MPEG-2)

19. Overview
• A video comprises of a sequence of frames.
Frame 1 Frame 2 Frame 3 Frame 4
• A video, of the duration of 1 second, generated by a TV camera usually
contains 24 frames or 30 frames.
• Each pixel in a frame is represented by three attributes (each 8 bits long) –
One luminance attribute and two chrominance attributes. (i.e. YCbCr)
Luminance(Y): Describes the brightness of the pixel.
Chrominance(CbCr):Describes the color of the pixel.
{Y, Cb,Cr}
Frame

20. YCbCr encoding
• converts block’s RGB data into YCbCr color space.
Raw Frame R G B
• RGB color space contains mutual redundancies, so it requires large space for
storage and high bandwidth for transmission.
• Encoding RGB into YCbCr color space reduces the mutual redundancies
Raw Frame Cr y Cb
example:

21. Video Scheme
Types of video schemes used for transmission -
1. Interlaced Video Scanning
• In this, a frame is divided into two separate fields – Top Fields and Bottom
fields. Frame
Bottom
Even numbered
rows in a frame.
Top Fields
Odd numbered rows
in a frame.
Field 1
Field 2
• The two successive fields (field 1 & field 2) are called a frame.
• Both the fields are sent one after another and display puts them back together
before displaying the full frame.
• Maximum frame rate is 60 frames/ second.

22. 2.Progressive Video Scanning
• In this, complete frame is send to display.
• Bandwidth requirement is twice as compared to Interlaced video scanning.
• Quality is good as frames come in sync and image is much sharper.
• Maximum frame rate is 30 frames/ second.

23. • MPEG stands for Motion Picture Experts Group established in 1988 as a
working group within ISO/IEC that has defined standards for digital
compression of audio & video signals. Such as-
1. MPEG-1 : It was the very first project of this group and published in 1993
• MPEG-1 defines coding methods to compress the progressively scanned
video.
• Commonly used in CD-i and Video CD systems.
• It supports coding bit rate of 1.5 Mbit/s.
2. MPEG-2: is an extension of mpeg-1 and published in 1995
• Commonly used in broadcast format, such as – Standard Definition TV (SDT)
and High Definition TV (HDT).
• It supports coding bit rate of 3 - 15 Mbit/s for SDT and 15 – 20 Mbit/s for HDT.

24. 3. MPEG-4 : introduced in 1998 and still in development ..
• MPEG-4 defines object based coding methods for mixed media data and
provides new features, such as – 3D rendering, animation graphics, various
types of interactivity etc.
• Commonly used in web based streaming media, CD, videophone, etc. .
• It supports bit rate of few Kbit/s of Mbit/s.

25. MPEG-2 Video Compression
MPEG-2 compresses a raw frame into three different kind of frames –
Raw Frame
I-Frame P-Frame B-Frame
• Intra coded frames (I-frames),
• Predictive coded frames (P-frames)
• Bi-directionally predictive coded frames (B-frames)
• Compressed frames (I, P & B frames) are organized in a sequence to form Group of Pictures
(GOP).
(GOP 1)
I B P B P B P B I
B
Group of
pictures

26. I MPEG-2 Frames
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.
Reference
P
Next
I
Reference
Previous
P
Next
P
Compressed
Raw Frame

27. 3. B - Frame
• Compression is similar to P-frame except that B-frame compression is done by referring
previous as well as following I-frame and or P frame.
References
I B P
Previous Future
References
P B I
Previous Future
References
P B P
Previous Future

28. INTERNET
PROTOCOL
TELEVISION
(IP-TV)

29. • 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.
29
What is IPTV?

30. Technology used in IP-TV
1.Broadband –the key element
• As Per The Telecom Regulatory Authority of India (TRAI):
“An always-on data connection that is able to support interactive services, and
has the capability of minimum download speed of 256 kbps”.

31. 2. DSL – DIGITAL SUBSCRIBER LINES
• DSL Family Tree
1. Symmetric DSL
• Provide identical data rates upstream & downstream
2. Asymmetric DSL
• Provide relatively lower rates upstream but higher rates
downstream

32. User Experience
Recommendations, Rating,
Guides etc.

33. IP-TV
CABLE
(VIDEO)
MEDIA
TELCO
(VOICE)
TELECOM
ISP
(DATA)
IT
Triple Play Service

34. Triple play setup using ADSL modem and
splitter
ADSL Modem
ADSL
Splitter
Video
IPTV Set Top Box (STB)
Internet
Voice service
Landline

35. Content Services in IP - TV Triple Play
1. Broadcast type
• IPTV
• Pay TV
• Electronic Programme Guide
(EPG)
• Live Streaming for VOD
• Progressive Downloads(Video,
gaming, music downloads)
3. On Demand type
• Interactive VOD(video on
demand)
• Client side Personal Video
Recording
• Pay per View(PPV)
• Time Shifted TV
• Others ( Music Download,
Music on Demand, TV based
internet access, caller ID pop
2. Interactive type up)
• Interactive TV
• Video Conferencing
• Interactive Online Network
Gaming
• Interactive E-Learning
4. Internet and Voice types
• VoIP
• Browsing on TV
• E-mail/SMS/MMS from TV
• Caller ID Popup
35

36. Future of ip-tv
• Replace the PC for entertainment (Limit it for programming, documenting)
• Everything (e-mail reading, FB, answering calls) from TV remote controller.

37. Thank You