ecen5553 telecom systems dr. george scheets week #14 [33] "huge growth for video telephony?...

ECEN5553 Telecom SystemsDr. George ScheetsWeek #14[33] "Huge Growth for Video Telephony? Skeptics Wary of

Predicted Data Crunch"[34] "The Picturephone is Here. Really."[35] "Perspective in Next-Generation Home

Networks: Toward Optical Solutions?"Final Exam

Friday, 11 December, 1400 – 1550 (Live)< 18 December (Distance Learning)

Exam #2 (90 points) final resultsHi = 88.1, Low = 50.4, Ave = 78.84, σ = 8.46A > 81, B > 70, C > 61, D > 52

ECEN5553 Telecom SystemsDr. George ScheetsWeek #14[33] "Huge Growth for Video Telephony? Skeptics Wary of

Predicted Data Crunch"[34] "The Picturephone is Here. Really."[35] "Perspective in Next-Generation Home

Networks: Toward Optical Solutions?"Final Exam

Friday, 11 December, 1400 – 1550 (Live)< 18 December (Distance Learning)

Exam #2 (90 points) final resultsHi = 88.1, Low = 50.4, Ave = 78.84, σ = 8.46A > 81, B > 70, C > 61, D > 52

INMARSAT PhonesINMARSAT Phones

Recently smallerphones have become

available for usewith latest satellites.

Parabolic AntennasParabolic Antennas

Geosynchronous Satellite vs Sun, Mid-day, Northern Hemisphere

Geosynchronous Satellite vs Sun, Mid-day, Northern Hemisphere

x

WinterSun is belowsatelliteorbital plane.

x

Fall Sun → sameplane assatellite.

x

Spring Sun→ sameplane asSatellite.

x

SummerSun is abovesatelliteorbital plane.

2013 Fall Sun Outage, Microspace's AMC-12013 Fall Sun Outage, Microspace's AMC-1

Source: www.ses.com/4551568/sun-outage-data

x

Market Split for Backhaul GearMarket Split for Backhaul Gear

Source: "High-Capacity Ethernet Backhaul Radio Systems for Advanced Mobile Data Networks", IEEE Microwave Magazine, August 2009.

Cell Towerwith

Point-to-Point RF link

Cell Towerwith

Point-to-Point RF link

ProtocolsProtocols ProprietaryProprietary 802.16802.16 802.11802.11

Free Space LasersFree Space Lasers

Sources: www.fsona.comwww.engadget.com/media/2006/02/gigabeam.jpg

Comparison: Optical vs RF BackhaulComparison: Optical vs RF Backhaul

Source:"The Next Challenge for Cellular Networks: Backhaul", IEEE Microwave Magazine, August 2009 .

194,000 GHz XX GHz

5.3 minutes downtime/year

8.8 hours downtime/year

Hughes Net (2013)Hughes Net (2013)

IridiumIridium

6 Low Earth orbits, 11 satellites per polar orbit

Not-so-miniature phone.image sources: Wikipedia& www.iridium.com

Iridium in AntarcticaIridium in Antarctica

Source: wikipedia

1

2 34

5

7

6

8

GlobalstarGlobalstar

image source: www.globalstar.com

The TCom Systems final is in three weeks Chief. I need some time off to study. Dick

TracywithWristRadio

DickTracywithWristRadio

Image Source:Wikipedia

You too could have had a Wrist RadioYou too could have had a Wrist Radio

Touchscreen GSM Cell Phone/

PDA/ Wristwatch

formerlyavailable at

www.thinkgeek.com

Stick-on Smart PhoneStick-on Smart Phone

NTSC TVNTSC TV Analog video Analog video

Obsolete as of June 2009Obsolete as of June 2009 30 frames/second30 frames/second 525 Scan Lines in a Frame, 525 Scan Lines in a Frame, ≈ ≈ 485 Active485 Active Resolution ≈ 640 x 480 pixelsResolution ≈ 640 x 480 pixels Video Bandwidth 4.2 MHzVideo Bandwidth 4.2 MHz RF Bandwidth 6.0 MHzRF Bandwidth 6.0 MHz

AM modulated VideoAM modulated VideoFM Modulated VoiceFM Modulated VoiceGuard BandGuard Band

Red, Green, & Blue used on MonitorsRed, Green, & Blue used on Monitors

Color VideoColor Video

Ele

ctro

nic

s

3 Pick-Up Elements

CCD’s

R

G

B

Camera

Ele

ctro

nic

s R

G

B

3 drivesignals

Monitor

Receiver electronics generate 3 signals withstrength proportional to light falling on the 3 camera pick-up elements.

Paints are SubtractivePaints are Subtractive

24 bit color 224 = 16.78 M colors24 bit color 224 = 16.78 M colors

256 Colors256 Colors

16 Colors16 Colors

MPEG Employs...MPEG Employs... Motion Estimation Algorithms

Tracks groups of NxN pixels... ...imperfectly if small and fast moving

Discrete Cosine Transforms Maps NxN pixel block spatial characteristics to

frequency domain Values Quantized

Some high frequency components zero'd out Gets rid of very fine detail Other values rounded off Causes some distortion (smearing)

Example of High Frequency FilteringExample of High Frequency Filtering

0 20 40 60 80 100 120 140

0

22

1

1270 i

Scan Line (Time Domain)

Monitor Image

FilteringFiltering

0 10 20 30 40 50 60 700

2

44

Xj

640 j

Scan Line (Frequency Domain)

Scan Line (Frequency Domain after zeroing)

0 10 20 30 40 50 60 700

2

44

0

Yj

640 j

1/2 the points thrown out (values < .1)

FilteringFilteringReconstructed Scan Lines (Time Domain after filtering)

0 20 40 60 80 100 120 1401

0

1

22

0.086

yi

1270 i

y

Monitor Image

Using NxNpixel blockslocalizesdistortion to NxN area,unlike thisexample.

Note Edges Aren't As SharpNote Edges Aren't As Sharp

y

Compare

Dick Tracy with Wrist RadioDick Tracy with Wrist RadioThis is a small JPEG imagethat's been enlarged.

With a good contrast monitor, you should be able to see evidence of theblocks, and should alsonote that the distortion tends to be localized to areas where the picture is changing.

JPEG DistortionJPEG Distortion

Note the fuzzygray 'cloud'.

MPEG Employs...MPEG Employs... Huffman Coding

Used to map DCT results to a bit streamUses unequal length code wordsHigh probability outputs get shorter words G.711: equal length code words (8 bits/sample) Morse Code: unequal length

Morse Code:An UnequalLength Code

Average bit rate is < fixed length code= 5 bits/character for the alphabet,

or 6 bits/characterfor alphabet &

numbers 0-9

Morse Code:An UnequalLength Code

Average bit rate is < fixed length code= 5 bits/character for the alphabet,

or 6 bits/characterfor alphabet &

numbers 0-9

Image Source: Wikipedia

Huffman CoderUnequal Length Code Words

High Probability? Assign Small Word.

Huffman CoderUnequal Length Code Words

High Probability? Assign Small Word. Suppose have 4 voltages to move:Suppose have 4 voltages to move:

-3 v-3 v 25%25%-1 v-1 v 5% 5%+1 v+1 v 40%40%+3 v+3 v 30%30%

2 bit code word11100001

Huffman Code111110

010

1,000,000 voltages/sec → 2,000,000 bps (2 bit code)1,000,000 voltages/sec → 1,900,000 bps (Huffman)

.25(3) +.05(3) + .40(1) + .30(2) = 1.9 bits/word on averageUniquely Decodable: 1110010110 = ?

MPEG Video Frame SequenceMPEG Video Frame Sequence1/30th second

Intrapictures (JPEG Still)

Bi-directional PicturesMostly

Motion EstimationTechniques

Predicted PicturesMostly changesince previousI or P frame