ECEN5553 Telecom Systems
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Wireless

ECEN5553 Telecom SystemsDr. George ScheetsWeek 15Read [32] "The Picturephone is Here. Really."[33] "Perspective in Next-Generation Home Networks"[34a] "Is This the Moment for Broadband over Power Lines?"[34b] "Dish Network for the Enterprise"Exam #2 Final Results (90 points)Hi = 87.3, Low = 33.0, Average = 65.19Standard Deviation = 13.83A > 77, B > 62, C > 53, D > 44Final ExamFriday, 14 December, 1400 - 1550 (Live)Not later than 21 December (Async DL)


Wireless

Wireless

  • LAN

    • 802.11 WiFi

  • MAN

    • Cell Systems3GSM & CDMA2000 → LTE

    • Free Space Lasers

    • Point to Point Radio802.16 WiMax

  • WAN

    • Geosynchronous Satellites

    • Low Earth Orbiting Satellites


Mpeg 1

MPEG 1

  • Standard since 1992

  • Compression of motion video & audio at about 1.5 Mbps (VHS Quality)

  • Targeted at digital playback & storage

  • Has Random Access capabilities

  • Divides picture up into 8x8 pixel blocksConverts blocks to bit stream


Mpeg 2

MPEG 2

  • Targets higher quality compression,typically at 3-6 Mbps bit rates

  • Being used for Direct Broadcast TV

  • Large chunks of MPEG2 used inU.S. HDTV standard

  • Standard since 1994

MP3

  • Web audio clips

  • Uses audio compression from MPEG 1

    • 12-1 typical compression ratio


Mpeg 4

MPEG 4

  • Aimed at Multimedia Coding

  • Bit rates from 8 Kbps - 40+ Mbps

  • Can codes objects as opposed to NxN blocks

    • Ability to interact & manipulate objects

  • Standard in 1999

  • Used in Quicktime 6, Direct TV


H 261 h 263 h 264

H.261, H.263, & H.264

  • Target real time videoconferencing

  • Subset of MPEG

  • Wide variety of bit rates

    • 64 Kbps - 128 Kbps: Face shot (video phone)

    • 384 Kbps: considered to be minimum speed for decent full screen videoconferencing

      • We are using H.263/4, mostly @ 768 Kbps

  • H.264 quality > H.263 > H.261

    • Newer protocols require more processing power

    • H.261 less common today


Video delivery over the air

Video Delivery: Over the Air

300 m

ATSC

Digital FDM

Since June 2009(FCC edict)

40-50 miles


Video delivery systems

Video Delivery Systems

  • Geo-Synchronous SatelliteAnalog NTSC (Obsolete)

    • 1 channel per 6 MHZ of RF bandwidth

    • 10 foot satellite dish

      Newer Systems digital MPEG2

    • Can get 4-6 "NTSC quality" SDTV channels per 6 MHz of RF bandwidth (TDM)

    • 1 ATSC HDTV signal per 6 MHz RF bandwidth

    • 18 inch satellite dish

    • MPEG4 = same quality, fewer bps


Video delivery systems1

Video Delivery Systems

  • Cable TV

    • Tree configuration

    • Distribution systems originally all coax

    • Originally Analog NTSC

    • BW ≈ 700 MHz

AMP

...

AMP

Headend

...

AMP

...

Initially Simplex Copper Coax


Video delivery systems2

Video Delivery Systems

  • Cable TV

    • Tree configuration

    • Distribution systems originally all coax

    • Fiber deployed from Head End side movingout

AMP

...

AMP

Headend

...

2nd Generation

Hybrid Fiber Coax

a.k.a. FTTx

AMP

...

Copper Coax

Fiber


Video delivery systems3

Video Delivery Systems

  • Cable TV

    • Now mostly digital ATSC, MPEG2/4

      • Analog NTSC now uncommon

    • Cable Modems require 2-way commo

      • Some 6 MHz channels pulled from TV pool

AMP

...

AMP

Headend

...

2nd Generation

Hybrid Fiber Coax

FTT curb

AMP

...

Copper Coax

Fiber


Video delivery systems4

...

...

Splitter

Splitter

Video Delivery Systems

  • Cable TV

    • Ultimate Goal: Fiber to the Home (FTTH)

    • Passive Optical Network

      • No active electronics in access network

Headend

Splitter

...

3rd Generation

FTT home

Fiber


Representative video bit rates hi lo quality

Representative Video Bit Rates (Hi ↓ Lo Quality)

  • 1.2 Gbps Uncompressed HDTV

  • 19.4 Mbps ATSC ( ≈ HDTV quality)

  • 8 - 9 Mbps MPEG4 ( ≈ HDTV quality)

  • 90 Mbps Uncompressed NTSC (SDTV)

  • 3 - 6 Mbps MPEG2 ( ≈ SDTV quality)

  • 1.5 Mbps MPEG4 ( ≈ SDTV quality)

  • 1.5 Mbps MPEG1 ( ≈ VHS < SDTV quality)

  • Note: ATSC, MPEG2, & MPEG4 support a wide variety of formats (SDTV ↔ HDTV)


Representative video bit rates hi lo quality1

Representative Video Bit Rates (Hi ↓ Lo Quality)

  • 1.2 Gbps Uncompressed HDTV

  • 19.4 Mbps ATSC ( ≈ HDTV quality)

  • 8 - 9 Mbps MPEG4 ( ≈ HDTV quality)

  • 90 Mbps Uncompressed NTSC (SDTV)

  • 3 - 6 Mbps MPEG2 ( ≈ SDTV quality)

  • 1.5 Mbps MPEG4 ( ≈ SDTV quality)

  • 1.5 Mbps MPEG1 ( ≈ VHS < SDTV quality)

  • How Much More Compression is Still Possible?

    • H.264 uses 30% less bits than MPEG4

      • November 2008 IEEE Communications Magazine


Compression

Compression

  • Requires a Signal with Redundant information

    • Must be some predictability

  • Compressing a Signal

    • Makes Result Less Redundant

  • You Can't Compress Forever


Pstn 33 6 kbps dial up modem

PSTN 33.6 Kbps Dial-Up Modem

  • CO Input Line Card Low Pass Filter limits BW (3 - 3.5 KHZ)

    • M-Ary Signaling (256 QAM or something even more complex)

  • Channel Capacity says max transfer is around 35 Kbps

CO

CO

PC

Server

2 Wire

‘4 Wire’

2 Wire

Digital TDM (1's & 0's)

64 Kbps

Modem

Protocol

Modem

Protocol


56 kbps modem requires digital source

56 Kbps Modem requires Digital Source

Modem

Bank

ISP

CO

CO

PC

Server

Digital

StatMux

1's & 0's

Digital TDM

1's & 0's

(ISDN,

T Carrier,

SONET)

DiscreteVoltage

(256 possible values)

PC to Server traffic will be slower, similar to previous slide.


Dial up pc to isp connectivity

Dial Up: PC to ISP Connectivity

Voice

network

Voice

Switch

Local Loop

Modem

PC

CO

Home

This configuration used to cause

call blocking problems at some

CO switches due to longer than

designed-for call holding times.

ISP Modem Bank

To Internet


Wireless

  • Fine print indicates

    • Uses Acceleration (compression)

    • Some material won't be compressed

    • Actual data transmission rates = standard dial up rates


Last mile options to the home

Last Mile Options to the Home

  • Point-to- Point Microwave

    • Cellular type technology

    • Fixed sites using directional antennas


Last mile options to the home1

Last Mile Options to the Home

  • Geo-synchronous Satellite

    • High Speed down links (300+ Kbps)

    • Satellite or Phone Line ‘up link’

Server

ISP

Phone


Last mile options to the home2

RIP

Last Mile Options to the Home

  • Low Earth Orbiting Satellite

    • Teledesic 2004? 2005? Never!

    • 300+ Kbps

    • Cellular type technologyCells MoveEarth units ‘fixed’

  • Point-to-Point Laser

    • Currently proprietary. Up to 2.5 Gbps speeds.

    • Aimed at businesses

  • Power Lines

    • Not as currently configured.


Powerline han

Powerline HAN

10/100BaseT Ethernet: PC ↔ Adapter

500 Mbps: Adapter ↔ Adapter


Last mile options

Last Mile Options

  • Cable Modem Network (DOCSIS)

    • Simplex 6 MHz downstream channels

    • Simplex 200 KHz to 6+ MHz upstream channels

    • All traffic traverses the Headend

AMP

...

AMP

Headend

...

2nd Generation

Hybrid Fiber Coax

FTT curb

AMP

...

Copper Coax

Fiber


Cable networks

Cable Networks

  • Have a Lot of BW (XXX MHz)

  • Allocate 6 MHz channels for various services

    • FDM

  • 6 MHz Channel can carry

    • 2 MPEG4 HDTV signals

    • 2-6 MPEG2/4 SDTV signals

    • 30-40 Mbps Cable Modem TrafficDOCSIS (Data over Cable Service Interface Specification)

      • Internet

      • VoIP


Cable pc to isp connectivity

Cable: PC to ISP Connectivity

Voice

network

PC

Cable TV

Network

Voice

Switch

Headend

EthernetNIC

Voice

Data

Video

Cable

Modem

Mux

Voice

Data

Home

ISP Router

Cable Modem will use shared

bandwidth to get to Cable TV

Headend.

To Internet


Cable modems

Cable Modems

  • Use FDM 6 MHz channels

    • Ethernet Frame format mapped to QPSK or QAM RF signal

    • 30 - 40 Mbps downstream

    • 320 Kbps to 30 Mbps upstream

  • Downstream

    • Head End controls use

    • TDM time slots, possibly assigned for a very short duration

  • Upstream

    • Head End assigns frequency band to end users (FDM)

    • Head End assigns time slots (Vendor specific algorithms)

      • Long term assignments (TDMA-like)

      • Short term assignments (StatMux-like)


Last mile options1

Last Mile Options

  • Digital Subscriber Line (xDSL)

    • Rides on top of Telco access network

    • Runs over twisted pair cabling

    • Various flavors exist

CO

...


Adsl pc to isp connectivity

ADSL: PC to ISP Connectivity

PC

Voice

network

Voice

Switch

EthernetNIC

CO

Local Loop

Voice (analog)

Data (ATM)

Data

ADSL

Modem

Voice

DSLAM

Splitter

Voice

Data

Home

ISP Router

ADSL off loads data traffic from

CO voice switches, & provides

more CO↔Home bandwidth.

To Internet


Wireless

ADSL

  • Plain Vanilla ADSL

    • 384 Kbps - 8 Mbps downstream

    • 16 Kbps - 640 Kbps upstream

  • Uses FDM

    • POTS analog voice stays in 0 - 4 KHz band

    • Upstream and Downstream signals mappedto higher frequency bands

      • Uses OFDM

    • ATM or Ethernet frame formats


Some of the flavored versions

Some of the Flavored Versions

  • ADSL2

    • Needs higher SNR than ADSL

    • 8 -12 Mbps downstream

    • 800 Kbps - 3.5 Mbps upstream

  • ADSL2+

    • Doubles used Bandwidth & Bit Rates

    • Can also bond multiple twisted pairsInverse Multiplex

  • VDSL2

    • 4 - 8 MHz BW, Inverse Multiplexing

    • 100 Mbps over short distances


Asymmetric digital subscriber line

Asymmetric Digital Subscriber Line

  • Can carry

    • A handful of 1.5 Mbps SDTV signals

    • Internet traffic (in left over BW)

    • Standard voice call

    • 0 HDTV signals

  • ADSL2+ potentially can carry 2 HDTV channels

    • Two 9 Mbps MPEG4

  • To Support Triple Play Service

    • TelCo's need to drive fiber down towards homes

    • FTTH: Gbps speeds possible

    • VDSL2+ can support 100 Mbps on copper out to 0.5 KmLonger reach if FTTC in place


Dsl speeds

DSL Speeds

(Copper)

source: www.convergedigest.com/blueprints/ttp03/bp1.asp?ID=232&ctgy=Loop


Video delivery systems5

Video Delivery Systems

Telco Digital Subscriber Line

Ultimate Goal: Fiber to the Home (FTTH)

Passive Optical Network

No active electronics in access network

...

...

Splitter

Splitter

Central Office

Splitter

...

3rd Generation

FTT home

Fiber


Iptv isp backbones

IPTV & ISP Backbones

  • 150 HDTV MPEG4 TV channels

    • 1.45 Gbps of traffic to move

    • StatMux, need ≈ 2.9 Gbps trunk capacity

    • Two OC-48's

    • Not a show stopper

      • Especially using multicastOne video stream services many customers

  • Video on Demand

    • Could be a problem

    • One video stream may service one customer


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