Broadband Access Networks and Services

1
Broadband Access Networks and Services
EE4541.759 Spring 2004

• Chapter 1
• INTRODUCTION
• Byeong Gi Lee
• Seoul National University

2
Core, Access Home Networks
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- The Scope of
Broadband Access Networks Services
-Streaming Video
BROADBAND SERVICES
-Conversational
Contents Provider
-Interactive Video
HOME NETWORK
-Other services
Service Processing
Service Processing
-TCP/IP -ATM -SDH/SONET -WDM/optics
Transport Processing
Transport Processing
Network Access
Network Access
-xDSL
ACCESS NETWORK (4541,759)
-Cable
CORE NETWORK (420.594)
-FTTx
-Wireless
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TABLE OF CONTENTS

• Chap 1. Introduction
• Chap 2. Twisted-pair based Access Network
• Chap 3. Cable based Access Network
• Chap 4. Fiber based Access Network
• Chap 5. Broadband Wireless Access Network
• Chap 6. Access Network Architecture
• Chap 7. Broadband Services

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I. INTRODUCTION

• Broadband Access Network (BAN)
• Broadband Services for BAN
• Conventional Subscriber Lines
• Multiplicity of Access Networks
• Structure of Broadband Access
• Evolution of Subscriber Lines
• Technical Foundation of BAN
• Access Network Standards
• Communication Environments

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Broadband Access Network (1)

• Subscriber loop is the transmission and
  signaling facility that connects the subscriber
  terminal equipment (NT) to the central office
  (AN).
• Access networks is a bridge that connects
  subscribers (i.e. users) to service providers
• Information services demand
• Conversational telecommunication (telephones)
• Broadband video distribution services (TV)
• Interactive data services (computers)
• Requires large bandwidth and high interactivity

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Broadband Access Network (2)
Reference model for BAN
A3
A2
A0
A1
A9
A4
Access
Network
A0A9 Interface
S1S3 Server
NIU Network Interface Unit
STU Set-Top Unit
NT Network Termination
TE Terminal
Equipment
RG Residential Gateway
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Broadband Services for BAN

• Television (analog, digital, interactive TV)
• Video on Demand (VoD)
• Near Video on Demand ( nVoD)
• World Wide Web
• Datacasting
• Video Streaming
• Games

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Conventional Subscriber Lines

• Central office (CO)access node(AN)- remote node
  (RN)- network termination (NT)Home network
• Feeder, distribution network
• Digital loop carrier(DLC), fiber loop carrier
  (FLC)
• Conventional subscriber lines
• enormous asset- 700 million subscriber lines
  worldwide
• twisted-pair (TP) dominant 90 of subscriber
  lines, 5 to 10-km of distance
• so far, mainly for POTS(plain ordinary telephone
  service)
• 4 kHz bandwidth

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Multiplicity of Access Networks

• Embedded base twisted pairs
• Different characteristics copper, coax, fiber,
  wireless
• Different applications point-to-pt,
  point-to-multipt
• Different population densities urban vs. rural
• Different geography ocean, hills, buildings,
  etc.
• Different business conditions infra, regulation
• Entrepreneurship investment, development
• gt Matter of trade-in between investment and
  performance (bandwidth, loss, delay)

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Structure of Broadband Access

• ADSL Asymmetric Digital Subscriber Line
• DBS Direct Broadcast Satellite
• FTTC Fiber To The Curb
• HFC Hybrid Fiber Coaxial
• LMDS Local Multipoint Distribution System
• MMDS Multi-channel Multipoint Distribution
  System
• MSO Multiple Service Operator

Digital DBS
Fiber or Wireless
MMDS/LMDS
LMDS only
Hub Station
DBS STB/ MMDS/LMDS STB
64Kbps
ISDN Adaptor
ISDN Line
MSO /CO
Analog Modem
56Kbps
ADSL Modem
6Mbps
Home Terminal
640Kbps
30Mbps
Coax
Cable Modem
Fiber
HFC
3Mbps
ONU
Coax or Copper
VDSL Modem
Fiber
52Mbps
FTTC/FTTO
3Mbps
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Evolution of Subscriber Lines

• Special treatments needed depending on
• the physical characteristics,
• the distance from the serving core network,
• the type of desired communication services.
• Three paths of evolution
• Apply advanced modulation techniques to TP- based
  transmission
• Replace TP-based subscriber loops with optical
  fibers
• Wireless-based supplement and renovation

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Evolution Paths

• TP-based evolution (1st stage of evolution)
• Mod Schemes QAM, CAP, DMT, DWMT
• HDSL, ADSL, SDSL, VDSL stages
• No requirement of any new deployments or changes
  to the loop other than attachment of the
  converters
• Fiber-based evolution (2nd stage of evolution)
• FTTO, FTTC, FTTH stages
• CATV network HFC enhanced with bi-directional
  capability for interactivity
• Wireless-based evolution (3nd stage of evolution)
• Limitation of bandwidth and security
• Economical alternative
• Mobility and network tractability

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TP-based Bandwidth Expansion

• Without modulation, 4kHz
• Digital Subscriber Line (DSL), 144kbps
• High-speed DSL (HDSL), 784kbps-1.5Mbps
• Asymmetric DSL (ADSL), 1.5-8Mbps/16-820kbps
  (5.4-3.6km)
• Very-high-speed DSL (VDSL), 13-52M/1.5-2.3M
  (300-1500m)

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Optical Fiber-based Evolution

• Fiber-in-the-loop (FITL)
• investment vs. demand, chicken-and-egg
• Fiber-to-the-office (FTTO) first
• Fiber-to-the-curb (FTTC) next
• Fiber-to-the-home (FTTH) final
• Hybrid-Fiber-Coaxial(HFC) contributes to
  evolution of CATV toward HTTH

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Wireless-based Evolution

• Advantages
• Complements wireline access networks
• Low initial investment, fast installation,
  flexibility
• Disadvantages
• Limited bandwidth, information security
• Narrow band services
• MPMP, cellular, cordless
• Broadband services
• MMDS, LMDS
• Fixed and mobile services

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Reference Architecture
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Access Networks and Standards (1)
Access Network
Telephony Standards
Data Standards
Video Standards
Analog TV
ATSC/DASE
Broadcast DTV
-
(NTSC, PAL, SECA
ATVEF
M), digital TV using
ATSC or DVB
Data Over Cable
Cable
Packet Cable
Open Cable SCTE DVS
Service Interface
Specification
(DOCSIS),
DAVIC/DVB
IP/PPP/ATM
Switched Digital
ADSL/G.Lite
Analog
(ADSL Forum)
Video (TBD)
Voice over ATM
Switched Digital
Various packet
Other DSLs
(VoATM) or Voice over IP
Video (TBD)
mode protocols
such as the
Point-to-Point
(VoIP)
Protocol Over
Ethernet
(PPPoE)
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Access Networks and Standards (2)
FSAN and other
Switched Digital
FTTx
VoATM/VoIP
initiatives
Video (TBD)
3G Wireless
IMT-2000
IMT-2000
-
LMDS
VoIP/VoATM
TBD
TBD
Analog TV, digital
MMDS
-
DOCSIS
TV using 8-VSB
High Altitude Long
TBD
TBD
-
Operation (HALO) aircraft
Blimps
TBD
TBD
-
Powerline, use of electric
TBD
TBD
-
power lines for data
transmission
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Modulation Techniques
Service
Modulation Techniques
ISDN (US)
2B1Q
US Direct Broadcast Satellite
QPSK
Vestigial Sideband (VSB)
US Digital Over-the-Air Broadcast
QAM-64, QAM-256
US Digital Cable Forward Channels
QPSK
US Digital Cable Return Channels
OFDM
European Digital Over-the-Air Broadcast
2B1Q
HDSL
DMT, CAP
ADSL
QAM, DMT
VDSL
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Communication Environment (1)

• Noise Mitigation Techniques
• Forward Error Correction
• Interleaving
• Spread Spectrum/Code Division Multiple Access
• Metallic Transmission Media
• Twisted-pair, Coaxial Cable
• Problems with High Frequency Attenuation,
  crosstalk
• External Impairments Leakage, impulse noise,
  loading coils, thermal noise, bridged taps

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Communication Environment (2)

• Fiber-Optic Transmission
• Modulation on/off keying (OOK), FM, AM
• Impairments attenuation, dispersion, handling
  problems, cuts and other damages, bending,
  clipping
• Improvements DWDM
• Wireless Transmission
• The higher frequency, the less distance
• Modulation QPSK, VSB, OFDM
• Impairments LOS, multipath, absorption,
  interference

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Transmission Media Summary
Modulation
Medium
Bit Rate
Bandwidth
Distance
Techniques
Coaxial cable in
QAM-64/
750 MHz
3.75 Gbps
lt 1.6 km
downstream
256
200kHz-
400Kbps-
Coaxial cable in upstream
QPSK
lt 1.6 km
3.2MHz
5Mbps
1 MHz
TP pair (ADSL)
DMT, CAP
6 Mbps
5 km
30 MHz
TP pair (VDSL)
52 Mbps
1.5 km
QAM, DMT
16 freq. of
Single-mode fiber
40 Gbps
500 km
OOK, DWDM
2.4 Gbps
each
Broadcast TV spectrum
8-VSB
19.39 Mbps
gt80 km
6 MHz
QPSK, OFDM
1.1 MHz
LMDS spectrum
2 Gbps
lt 5 km