Trends in Telecommunications Technology

1
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

2
Introduction

• Purpose

To provide non-engineers with an overview of
major trends in telecommunications technology
3
Outline

• Review of Basic Concepts
• Answer Seven Questions About Trends
• Analog versus Digital -- Why Digital?
• Voice versus Data -- Whats the Difference?
• Circuit Switching versus Packet Switching -- Why
  Packet Switching?
• Narrowband versus Broadband -- Why Broadband?

4
Outline

• Answer Seven Questions About Trends (Contd)
• 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

5
The Digital Revolution

• Analog Signal

Intensity
Time
6
The Digital Revolution

• Digital Signal

Intensity
Time
0 1 0 0 0 1 0 1 1 0 0
7
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
8
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
9
Analog vs. Digital Why Digital?

• Why Digital?
• Digital Regeneration

10
Analog vs. Digital -- Why Digital?

• Advantages
• Signal Regeneration
• Ease of Multiplexing
• Ease of Encryption
• Ease of Signaling
• Use of Modern Technology (Moores Law)
• Performance Monitorability
• Operability at Low Signal/Noise or
  Signal/Interference

11
Analog vs. Digital -- Why Digital?

• Advantages (Contd)
• 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
12
Voice vs. Data-- Whats 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

13
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
14
Circuit Switching vs. Packet Switching -- Why
Packet Switching?

• Traditional Circuit Switched Connection

IXC POP
IXC POP
Key LECLocal Exchange Carrier IXCInterexchange
Carrier CO Central Office POPPoint of Presence
LEC CO
LEC CO
15
Circuit Switching vs. Packet Switching -- Why
Packet Switching?

• Traditional Packet Switched Network

PS
Host Computer
PS
Dumb Terminal
PS
PS
"Dumb" Terminal
A
M
PS
A
M
PS
Addressed Packets
Dumb Terminal
(e.g. collection of
characters)
PS Packet Switch Functions Error Control,
Routing, Flow Control
16
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

17
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

18
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

19
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

20
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

21
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

22
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
23
Narrowband vs. Broadband-- Why Broadband?

• Illustration of the Importance of Bandwidth

Computer Monitor
24
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

25
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

26
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

27
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

28
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

29
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)

30
The Network of the Future

• Network Trends/Goals from a Technological
  Perspective (Contd)
• Extension of this platform using wireless
  technology to allow users to communicate
  anyplace, anytime, in any mode or combination of
  modes.

31
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
Backbone
Local/Regional
32
Contact Information
Dale N. Hatfield Adjunct Professor Interdisciplin
ary Telecommunications Program University of
Colorado at Boulder Engineering Center -
ECOT-311 Campus Box 530 Boulder, CO
80309-0530 Main Tel [phone] Direct Dial
1 303-492-6648 Fax [phone] Email
dale.hatfield_at_ieee.org or hatfield_at_spot.colorado.e
du