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 Time Intensity Analog Signal

Digital Signal The Digital Revolution Time Intensity

The Digital Revolution Analog to Digital and Digital to Analog Conversion Analog Signal A/D D/A Sequence of Numbers (Transmitted as a Sequence of Binary Numbers) On and Off Pulses Representing Binary Numbers

Analog vs. Digital -- Why Digital? Analog Amplification vs. Digital Regeneration AMP INPUT OUTPUT Digital Regeneration: “Perfect” Signal is Regenerated Analog Amplification: Noise Accumulates INPUT Repeater

Analog vs. Digital – Why Digital? Why Digital? –Digital Regeneration

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

Source: Bellamy, Digital Telephony 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

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: 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) Circuit Switching vs. Packet Switching -- Why Packet Switching? Types of Switching Source:

Circuit Switching vs. Packet Switching -- Why Packet Switching? Traditional Circuit Switched Connection LEC CO IXC POP Key: LEC=Local Exchange Carrier IXC=Interexchange Carrier CO =Central Office POP=Point of Presence

Circuit Switching vs. Packet Switching -- Why Packet Switching? "Dumb" Terminal “Dumb” Terminal Addressed Packets (e.g. collection of characters) Host Computer PS M M A A Traditional Packet Switched Network PS = Packet Switch Functions: Error Control, Routing, Flow Control

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 Customer Premises Access Backbone Local/Regional Customer NodeNetwork Node IP Based Network Integrated Network with Integrated Access Access Network: DSL, Cable Modem, Wireless (Cellular, Wi-Fi, etc), Satellite, Other Integrated End User Device (Voice, Data, Video, Multimedia)

Contact Information Dale N. Hatfield Adjunct Professor Interdisciplinary Telecommunications Program University of Colorado at Boulder Engineering Center - ECOT-311 Campus Box 530 Boulder, CO Main Tel: Direct Dial: Fax: or