Transcript Recent Developments in Telecommunications Technology

Trends in Telecommunications
Technology
Presentation by
Dale N. Hatfield
Adjunct Professor, University of Colorado at Boulder
at the
Institute for Regulatory Law and Economics (IRLE)
Aspen Colorado
May 21, 2006
Introduction
• Purpose:
To provide non-engineers with an overview of major trends in
telecommunications technology
Outline
• Review of Basic Concepts
• Answer Seven Questions About Trends
– Analog versus Digital -- Why Digital?
– Voice versus Data -- What’s the Difference?
– Circuit Switching versus Packet Switching -- Why
Packet Switching?
– Narrowband versus Broadband -- Why
Broadband?
Outline
• Answer Seven Questions About Trends
(Cont’d)
– High Latency versus Low Latency -- Why Low
Latency?
– Intelligence Interior to the Network versus at the
Edge of the Network -- Why at the Edge?
– Wired versus Wireless -- Why Wireless?
• The Network of the Future
The Digital Revolution
• Analog Signal
Intensity
Time
The Digital Revolution
• Digital Signal
Intensity
0 1 0 0 0 1 0 1 1 0 0
Time
The Digital Revolution
• Analog to Digital and Digital to
Analog Conversion
Sequence of Numbers (Transmitted as
a Sequence of Binary Numbers)
Analog Signal
Analog Signal
12.3 12.6 12.9 13.6 13.9 14.8 14.1 13.9
D/A
A/D
On and Off Pulses
Representing
Binary Numbers
Analog vs. Digital -- Why Digital?
• Analog Amplification vs. Digital Regeneration
AMP
AMP
AMP
OUTPUT
INPUT
Analog Amplification: Noise Accumulates
Repeater
Repeater
Repeater
INPUT
Digital Regeneration: “Perfect” Signal is Regenerated
Analog vs. Digital – Why Digital?
• Why Digital?
– Digital Regeneration
Repeater
Analog vs. Digital -- Why Digital?
• Advantages
–
–
–
–
–
–
–
Signal Regeneration
Ease of Multiplexing
Ease of Encryption
Ease of Signaling
Use of Modern Technology (“Moore’s Law”)
Performance Monitorability
Operability at Low Signal/Noise or
Signal/Interference
Analog vs. Digital -- Why Digital?
• Advantages (Cont’d)
– Integration of Switching and Transmission
– Accommodation of Other Services
• Disadvantages:
– Larger Bandwidth Requirements
– Critical Timing
– Need for Analog to Digital Converters
Source: Bellamy, Digital Telephony
Voice vs. Data
-- What’s the Difference?
• Voice
–
–
–
–
Information rate “constant”
Intolerant of delays and variations in delay
Tolerant of noise/distortion
Symmetrical
• Data
–
–
–
–
Information rate “bursty/fractal”
Tolerant of delay
Intolerant of noise/interference
Often asymmetrical
Circuit Switching vs. Packet Switching
-- Why Packet Switching?
• Types of Switching
Circuit Switching: The practice of establishing an end-to-end connection
between users of a network. The associated facilities are dedicated to the
particular connection for the duration of the call.
Message Switching: The practice of transporting complete messages from a
source to a destination in non-real time and without interaction between the
source and destination, usually in a store-and-forward fashion
Packet Switching: The practice of transporting messages through a network, in
which long messages are subdivided into short packets. The packets are then
transmitted as in message switching (i.e, in a store-and-forward fashion)
Source:
Circuit Switching vs. Packet
Switching -- Why Packet Switching?
• Traditional Circuit Switched Connection
IXC POP
IXC POP
Key:
LEC=Local Exchange Carrier
IXC=Interexchange Carrier
CO =Central Office
POP=Point of Presence
LEC CO
LEC CO
Circuit Switching vs. Packet Switching
-- Why Packet Switching?
• Traditional Packet Switched Network
PS
“Dumb” Terminal
Host Computer
PS
PS
PS
"Dumb" Terminal
PS
“Dumb” Terminal
PS
PS = Packet Switch
Functions: Error Control,
Routing, Flow Control
Addressed Packets
(e.g. collection of
characters)
Circuit Switching vs. Packet Switching
-- Why Packet Switching?
• Because of the differences between voice
and data, in the past:
– Circuit switching and time division
multiplexing were used in the public switched
telephone network (PSTN)
– Packet switching and statistical multiplexing
was used in public (and private) switched data
networks
Circuit Switching vs. Packet Switching
-- Why Packet Switching?
• Circuit Switching and Time Division
Multiplexing
– Advantages
• No transmission delay
– Disadvantages
• Only fixed increments of bandwidth provided
• Inefficient channel utilization for bursty traffic
• High call setup overhead
Circuit Switching vs. Packet Switching
-- Why Packet Switching?
• Packet Switching and Statistical
Multiplexing
– Advantages
• User does not consume network resources when no
information is being sent
• “Bandwidth on demand”
• Efficient utilization of transmission lines and ports
• Efficiently handle asymmetric traffic
• Offers “always on” connectivity
Circuit Switching vs. Packet Switching
-- Why Packet Switching?
• Packet Switching and Statistical
Multiplexing
– Advantages
• Provides the ability to handle different types of
signals -- voice, data, image, and video on common
transmission and switching platforms
– Disadvantages
• Delay (higher latency)
• Per packet overhead
Narrowband vs. Broadband
-- Why Broadband?
• In simple terms, bandwidth is just a measure
of how fast information can be transmitted
• The larger the bandwidth, the more
information that can be transmitted in a
given amount of time
Narrowband vs. Broadband
-- Why Broadband?
• In the digital world, bandwidth is measured
in bits per second
• Analogous measures: vehicles per hour or
gallons per minute
Narrowband vs. Broadband -Why Broadband?
• To over simplify:
– Voice requires only narrow
bandwidths (narrowband)
– Still images require wide bandwidths
(wideband)*
– Video requires broad bandwidths
(broadband)
*For transmission of the image in a reasonable amount of time
Narrowband vs. Broadband
-- Why Broadband?
• Illustration of the Importance of Bandwidth
Computer Monitor
High Latency vs. Low Latency
-- Why Low Latency?
• In simple terms, latency just refers to delay
• Latency is the amount of time it takes
information (e.g., a packet) to travel from
source to destination
• In combination, latency and bandwidth define
the speed and capacity of a network
• Low latency is critical in voice
communications and certain real-time data
communications applications
Intelligence Interior to the Network
versus at the Edge of the Network -Why at the Edge?
• Architecture of the Traditional Public
Switched Telephone Network
– Circuit switching
– “Dumb” terminals with limited capabilities
– “Intelligence” residing in switches, intelligent
peripherals, service control points, etc. interior
to the network
– Services created inside the network
Intelligence Interior to the Network
versus at the Edge of the Network -Why at the Edge?
• Architecture of Networks Based Upon the
Internet Protocol (IP)
– Packet switching
– “Dumb” network
– “Intelligent” terminals (e.g., PCs) with a rich
set of capabilities
– Services created in terminals/servers at the edge
of the network
Wired versus Wireless -- Why Wireless?
• Motivation for Wireless
– Increased mobility of the workforce and society
more generally
– Increased efficiency and convenience and
safety
– Potentially lower infrastructure costs for certain
fixed applications; more fungible investment
– Other
Wired versus Wireless -- Why Wireless?
• Evolution of Commercial Mobile Radio
Services
– First generation: analog, circuit switched,
narrowband
– Second generation: digital, circuit switched,
narrowband
– Third generation: digital, packet oriented,
wideband/broadband
The Network of the Future
• Network Trends/Goals from a
Technological Perspective:
– All applications -- voice, data, image, video,
multimedia -- conveyed on an all digital,
packet-switched, broadband, low latency
network or “platform”
– A “network of networks” platform that uses
common, open, non-proprietary standards
and protocols (e.g., the Internet Protocol -IP)
The Network of the Future
• Network Trends/Goals from a
Technological Perspective: (Cont’d)
– Extension of this platform using wireless
technology to allow users to communicate
anyplace, anytime, in any mode or combination
of modes.
The Network of the Future
• Integrated Network with
Integrated Access
Integrated End User Device
(Voice, Data, Video,
Multimedia)
Customer Node
Network Node
IP Based
Network
Access Network: DSL,
Cable Modem, Wireless
(Cellular, Wi-Fi, etc),
Satellite, Other
Customer Premises
Access
Local/Regional
Backbone
Contact Information
Dale N. Hatfield
Adjunct Professor
Interdisciplinary Telecommunications Program
University of Colorado at Boulder
Engineering Center - ECOT-311
Campus Box 530
Boulder, CO 80309-0530
Main Tel: +1 303-492-8916
Direct Dial: +1 303-492-6648
Fax: +1 303-492-1112
Email: [email protected]
or [email protected]