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