Transcript Lecture Slides - Stanford University

EE 104: Introduction to Communications
Professor Andrea Goldsmith
Outline
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Course Information and Policies
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Communication Systems Today
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Future Systems
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Design Challenges
Course Information
(see web or handout for more details)
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Instructor: Andrea Goldsmith, Packard 371, andrea@ee, Ext:
56932, OHs: W 11am-12pm, Th 5:30-6:30.
Class Homepage: www.stanford.edu/class/ee104
TAs:
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Jaron Charles, jcharles@stanford, OHs: Th 7-9pm, Email W 8:30-9:30pm
Nikola Stikov, nikola@stanford, OHs: F 11am-1pm, Email Th 6-7pm
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Class mailing list: ee104-students (automatic for registered
students), ee104-staff for instructor/TAs, guest list available
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Discussion Section: W 6:15-7:15pm; not televised
Book: An Introduction to Analog and Digital Communications
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Grading: HWs 30%, Midterm 30%, Final 40%
No Lectures Jan. 15 and Feb. 24
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Other lectures that week start at 12:50pm, or can schedule makeups
Class Policies
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Exam policy: Exams must be taken at their scheduled
times. Exceptions only in very rare circumstances.
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HW policy:
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Midterm: 2/12 from 12:30-2:05
Final: 3/20 from 8:30-11:30am.
Assigned Friday, due following Friday. Lose 25% credit per day
late.
Up to 3 students can collaborate on 1 writeup. All collaborators
must work out all problems.
SITN students:
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HWs must be faxed or postmarked by HW deadline for regular
students. Exceptions must be cleared in advance.
Exams must be taken at same time as for regular students.
Communication Systems
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Provide for electronic exchange of multimedia data
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Voice, data, video, music, email, web pages, etc.
Communication Systems Today
Radio and TV broadcasting (covered later in the course)
 Public Switched Telephone Network (voice,fax,modem)
 Cellular Phones
 Computer networks (LANs, WANs, and the Internet)
 Satellite systems (pagers, voice/data, movie broadcasts)
 Bluetooth
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PSTN Design
Local Switching
Office (Exchange)
Local Line
(Twisted Pair)
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Local Switching
Office (Exchange)
Long Distance Lines
(Fiber)
Fax
Modem
Local exchange
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Handles local calls
Routes long distance calls over high-speed lines
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Circuit switched network tailored for voice
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Faxes and modems modulate data for voice channel
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DSL uses advanced modulation to get 1.5 Mbps
Cellular System Basics
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Geographic region divided into cells
Frequencies/timeslots/codes reused at spatially-separated
locations (analog systems use FD, digital use TD or CD)
Co-channel interference between same color cells.
Handoff and control coordinated through cell base stations
BASE
STATION
Cell Phone Backbone Network
San Francisco
BS
BS
New York
MTSO
PSTN
MTSO
Internet
BS
Local Area Networks (LANs)
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1011
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LANs connect “local” computers
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Breaks data into packets
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Packet switching (no dedicated channels)
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Proprietary protocols (access,routing, etc.)
Wireless Local Area
Networks (WLANs)
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1011
Internet
Access
Point
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WLANs connect “local” computers (100m range)
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Breaks data into packets
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Channel access is shared (random access)
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Backbone Internet provides best-effort service
Wide Area Networks:
The Internet
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Internet
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LAN
Bridge
MAN
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Bridge
LAN
Satellite and
Fiber Lines
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Many LANs and MANs bridged together
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Universal protocol: TCP/IP (packet based).
Guaranteed rates or delays cannot be provided.
Hard to support user mobility.
Highly scalable and flexible topology
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Satellite Systems
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Cover very large areas
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Different orbit heights
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Optimized for one-way transmission
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Geosynchronous (GEO) versus low earth orbit
(LEO)
Paging, radio and movie broadcast
Most two-way systems struggling or bankrupt
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Expensive alternative to terrestrial system
Bluetooth
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Cable replacement for electronic devices
 Cell
phones, laptops, PDAs, etc.
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Short range connection (10-100 m)
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1 data (721 Kbps) and 3 voice (56 Kbps) channels
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Rudimentary networking capabilities
Future Systems
Ubiquitous Communication Among People and Devices
Nth Generation Cellular
Nth Generation WLANs
Nth Generation Internet
Wireless Entertainment
Sensor Networks
Smart Homes/Appliances
Automated Cars/Factories
Telemedicine/Learning
All this and more…
Design Challenges
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Hardware Design
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System Design
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Precise components
Small, lightweight, low power
Cheap
High frequency operation
Converting and transferring information
High data rates
Robust to noise and interference
Supports many users
Network Design
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Worldwide anywhere any-time connectivity
Speed
Main Points
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Communication systems send information
electronically over communication channels
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Many different types of systems which convey
many different types of information
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Design challenges include hardware, system, and
network issues
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Communication systems recreate transmitted
information at receiver with high fidelity
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Focus of this class is design and performance of
analog and digital communication systems