Designing Wireless Communication System

DESIGNING WIRELESS COMMUNICATION SYSTEM

Troy Lynn Bullock – Reagan High School Houston Independent School District

Faculty Mentor : Dr. Tie Liu Information Theory and Coding for Wireless Broadcast Networks Electrical Electronics & Communications Engineering Graduate Assistant: Neeharika Marukala

Communication Communication is a term that comes

from Greek, it means, ‘communicating at a distance’ through signals of varied nature coming from a transmitter to a receiver.

Communication In ancient time communication began with the use of

visual signals such as; smoke, semaphore telegraphs, and

signal flags, and audio signals such as; drumbeats, lung blown horns,

or loud whistles.

Communication In the modern age, the true ‘jump’ in terms of quality

came with the advent of electricity. Electromagnetic energy, in fact, is able to transport information in an extremely fast way (ideally to the speed of light), in a way that previously had no equals in terms of costs and reliability.

Wireless Communication Wireless communication is the transfer of

information over a distance without the use of wires.

Some examples of wireless technology:- Security Systems- Television remote control- Cellular telephone (phones and modems)

- Wi-Fi

- Wireless energy transfer

Bandwidth Wireless communication uses electromagnetic

transmission.

Electromagnetic transmission operates over a range of spectrum called, bandwidth.

Bandwidth is a highly regulated commodity.

Bandwidth is extremely expensive.

Bandwidth Bandwidth is a valuable and limited resource.

For example, an FM radio receiver’s tuner spans a limited range of frequencies (87.5 – 108 MHz)

A government agency, the FCC (Federal Communications Commission) in the United States may apportion the regionally available bandwidth to licensed broadcasters so that their signals do not mutually interfere.

Each transmitter owns a slice of bandwidth, a valuable (if intangible) commodity.

Impact of Bandwidth Basic Communication Setup

Pulse –shaping Filters

Basic Communication SetupInformation

sourceDestination

Modulator Demodulator

Physical Medium

bits

transmittervoltage

s

bits

voltages

waveforms waveform

s

DACDigital Analog

Converter

ADCAnalog Digital

Converter

receiver

distortion

channel

Pulse Shaping Filter The voltages are converted into

waveforms using a pulse shaping filter.

This is where bandwidth comes into play.

Its purpose is to make the transmitted signal better suited to the communication channel by limiting the effective bandwidth of the transmission.

Sinc Pulse Shaping Filter

Time Domain Frequency Domain

Raised Cosine Pulse Shaping Filter

Time Domain Frequency Domain

Research Activities Given a bandwidth, the number of

channel uses per second is fixed.

The goal of transmitter/receiver design is to maximize the number of bits that can be reliably communicated per channel use.

Reliable communication in the presence of noise.

Design Objectives Energy efficient: The energy spent

on transmission is proportional to the number of bits transmitted.

Bandwidth efficient: The number of bits transmitted is proportional to the channel uses.

Reliable: The probability of error decreases as a function of the number of bits transmitted.