S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Electrical Electrical Communications SystemsCommunications Systems
0909.331.010909.331.01 Spring 2005Spring 2005
Shreekanth MandayamECE Department
Rowan University
http://engineering.rowan.edu/~shreek/spring05/ecomms/
Lecture 1aLecture 1aJanuary 18, 2005January 18, 2005
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
PlanPlan• Why are we studying ECOMMS?
• Technology successes, Trends and Decisions
• What is a communications system?• Objectives• Block diagram • What limits our ability to communicate?• Fundamental limits - Shannon’s Theorem
• Wireless comm evolution• What are we studying in this course?• Course logistics
• ECOMMS Readiness QUIZ, next Monday!
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Telecomm TrendsTelecomm Trends
http://money.cnn.com/2003/12/23/markets/yir_bigwinners03/index.htm
http://money.cnn.com/2003/12/12/markets/yir_biglosers03/index.htm
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Telecomm Trends (continued)Telecomm Trends (continued)
http://money.cnn.com/2004/12/17/markets/yir04_markets/
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Motorola V710
Basic Features1.2 megapixel camera with flash
Record and Send 15 second videos Connectivity via Bluetooth
500 Phone Book Entries Speakerphone
Personal Organizer Voice Activated Dialing
Meets FCC SAR limit. Manufacturer's highest FCC reported SAR 1.40 at ear, 1.07 on body. Actual SAR
may vary. Supported Optional Features
Video & PIX Messaging GET IT NOW
TXT Messaging Picture Messaging
Internet Ready NationalAccess
http://www.verizonwireless.com/
Tech SuccessTech Success
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
http://www.esa.int/SPECIALS/Cassini-Huygens/
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Decisions, decisions…..Decisions, decisions…..
• I live in the Philadelphia metro area. What cell-phone carrier should I choose?• Verizon wireless, Cingular, Spring PCS, AT&T……?
• I’m designing the next generation microprocessor. It’s going to be connected to Internet2. How do I design the right size the memory buffer?
• I’m designing the remote navigation for the Mars Rover. What’s the right bandwidth/data rate for control signal transmission?
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
What is a communications What is a communications system?system?
• Communications Systems: Systems designed to transmit and receive information
Info Source
Info Source
Info Sink
Info Sink
CommSystem
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Block DiagramBlock Diagram
ReceiverRx
receivedmessage
tosink
)(~ tm
TransmitterTx s(t)
transmittedsignal
Channelr(t)
receivedsignal
m(t)message
from source
Info Source
Info Source
Info Sink
Info Sink
n(t)noise
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
What limits our ability to What limits our ability to communicate?communicate?
• NOISE!!!!!• Noise: an unwanted, random fluctuation in the
signal• Without the effects of noise, a message with
infinitesimally small power could be transmitted over infinitely large distances
• ALL advances in communications technology are advances to combat the effects of noise
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Fundamental Limit: Fundamental Limit: Shannon’s Theorem Shannon’s Theorem (1948,1949)(1948,1949)
• Theoretical limit for error-free transmission in a communications system in the presence of noise
• Source Data Rate: R [bits/sec]
• Channel Capacity:
C = B log2(1 + S/N) [bits/sec]
• R < C: No Error!!!http://www.bell-labs.com/news/2001/february/26/1.html
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Wireless Comm Evolution:Wireless Comm Evolution: UMTS (3G) UMTS (3G)
http://www.3g-generation.com/http://www.nttdocomo.com/reports/010902_ir_presentation_january.pdf
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
Evo
luti
on
Evo
luti
on
TECHNOLOGY FEATURES
1-GLate 1970’s, early 1980’s
AMPS Advanced Mobile Phone Service
-Analog voice service
- No data service
2-G1990’s
CDMA Code Division Multiple Access
TDMA Time Division Multiple Access
GSM Global System for Mobile Communications
PDC Personal digital cellular
Digital voice service
- 9.6K to 14.4K bit/sec.
- CDMA, TDMA and PDC offer one-way data transmissions only
- Enhanced calling features like caller ID
- No always-on data connection
3-G2000 and beyond
W-CDMA Wide-band Code Division Multiple Access
CDMA-2000 Based on the Interim Standard-95 CDMA standard
TD-SCDMA Time-division synchronous CDMA
- Superior voice quality
- Up to 2M bit/sec. always-on data
- Broadband data services like video and multimedia
- Enhanced roaming
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
And there’s more….And there’s more….
3
A View of 4GA View of 4GA View of 4G
• Domain of 4G extends beyond 1G, 2G, and 3G• > 2 Mbps in a wide-area mobile system (> 20 Mbps peak)
• Could coexist with 2G and 3G
• 4G is not necessarily defined by the bit rate, but by a significant advance in system capability beyond what can be achieved with 3G
Data Rate
Coverage Area,
Mobility
Macrocell,High Mobility
Microcell,Limited Mobility
Fixed Access
64kbps 2Mbps 200Mbps
P-MP (LMDS)Milli-wave LAN
2G2G
WLAN
4G4G3G3G
Joseph M. Nowack, http://www.jacksons.net/~tac/
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
ECOMMS: What are we studying?ECOMMS: What are we studying?
Electrical Communications Systems
•Measures of information and noise•Capacities for information transmission
•Design of communications systems•Measures of performance
•Communications circuits
•Communications protocols
HardwareINdependent
Hardwaredependent
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
ECOMMS: TopicsECOMMS: Topics
ReceiverRx
)(~ tmTransmitterTx s(t)
Channelr(t)
m(t)
Modulation circuits and systems
DSP
Demodulation circuits and systems
DSP
Noise
Wire/wirelessAntennas/Coupling
Antennas/Coupling
Analog/digital
Protocols
Fundamental limits
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
ECOMMS: DetailsECOMMS: Details
Probability
Inform ation
Entropy
Channel Capacity
Discrete
Pow er & Energy S ignals
Continuous Fourier T ransform
Discrete Fourier T ransform
Baseband and Bandpass S ignals
Com plex Envelope
G aussian Noise & SNR
Random VariablesNoise Calculations
Continuous
Signals
AMSw itching M odulator
Envelop Detector
DSB-SCProduct M odulatorCoherent Detector
Costas Loop
SSBW eaver's M ethodPhasing M ethod
Frequency M ethod
Frequency & Phase M odulationNarrow band/W idebandVCO & S lope Detector
PLL
Analog
Source EncodingHuffm an codes
Error-control EncodingHam m ing Codes
Sam plingPAM
QuantizationPCM
Line Encoding
T im e Division M uxT 1 (DS1) Standards
Packet Sw itchingEthernet
ISO 7-Layer Protocol
BasebandCODEC
ASKPSKFSK
BPSK
QPSK
M -ary PSK
QAM
BandpassM ODEM
DigitalDigita l Com m T ransceiver
System s
Electrical Com m unication System s
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
ECOMMS: Course LogisticsECOMMS: Course Logistics
http://engineering.rowan.edu/~shreek/spring05/ecomms/
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
ECOMMS Readiness QuizECOMMS Readiness QuizNEXT MONDAY, Jan 24, 12:40 PM
Room 204/206
CLOSED Book and Notes
Topics:
Complex algebra, Phasors, Fourier Series, AC Circuits
BRING YOUR CALCULATOR!
S. Mandayam/ ECOMMS/ECE Dept./Rowan University
SummarySummary