Wilamowski B.M., Irwin J.D. The Industrial Electronics Handbook. Second Edition: Industrial Communication Systems

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Ad Hoc Networks 7-3

rapid.deployment.of.these.systems.at.a.lower.cost,.without.having.to.lay.cables.to.each.sensor..To.sum.up,.

ad.hoc.netw

orks

.and.alte

rnative

.techn

ologies

.are.enab

ling

.direc

.inte

lligent

.comm

unication

.betw

een

.enti

ties.

. is.new.para

digm

.is.poised.to.chan

.the.way.we.inte

ract

.with.the.worl

.and.perf

orm

.die

rent

.task

7.1.3 ad Hoc Network Characteristic

One.of.the.key.characteristics.of.ad.hoc.networks.is.mobility.due.to.rapid.repositioning.of.nodes.. ese.

node

.can.eith

.move.inde

pendently

.or.are.grou

ped

.toget

her

.whil

.thei

.move

ment

.can.be.rand

or.alon

.prep

lanned

.rout

es.

. ese.mobi

lity

.mode

.can.have.major.impa

.on.sele

cting

.an.appr

opriate

rout

ing

.sche

me,

.whic

.may.inu

ence

.the.perf

ormance

.of.the.netw

ork.

.Anot

her

.char

acteristic

.of.ad.hoc.

netw

orks

.is.mult

ihopping

.wher

.the.path.from.the.sour

.to.dest

ination

.incl

udes

.seve

ral

.othe

.inte

rme-

diate

.node

.Wide-

area

.ad.hoc.netw

orks

.oen.exhi

bit

.mult

iple

.hops.for.obst

acle

.nego

tiation,

.spec

trum

reus

.and.ener

.cons

ervation.

.Besid

es,

.an.ad.hoc.netw

ork

.must.eec

tively

.hand

.prob

lems

.pert

aining

to.add

ressing,

.rou

ting,

.clu

stering,

.posi

tion

.ide

ntication,

.and.pow

.con

trol,

.jus

.to.nam

.a.few

Another

.impo

rtant

.feat

ure

.of.the.ad.hoc.netw

orks

.is.ener

.cons

ervation.

.Desig

ning

.ener

gy-ecient

proto

col

.is.crit

ical

.for.prol

onged

.oper

ation

.since.most.ad.hoc.node

.have.limi

ted

.powe

. e.ad.hoc.

netw

orks

.can.some

times

.grow.up.to.seve

ral

.thou

sand

.node

.all.movi

.in.an.unpr

edictable

.mann

er.

Alth

ough

.it.may.be.possi

ble

.to.nd.an.ad.hoc.solu

tion

.for.a.few.fast.node

.or.for.a.very.larg

.num-

.of.stat

.node

.the.prob

lem

.aris

.when.a.larg

.numbe

.of.hete

rogeneous

.node

.move.in.rand

dire

ction

.with.die

rent

.spee

.over.an.unpr

edictable

.terr

ain.

. us,.mult

ihop,

.mobi

lity,

.and.larg

.net-

ork

.size.combi

ned

.with.vary

ing

.devi

.char

acteristics

.(het

erogeneity,

.band

width,

.and.batt

ery

.powe

cons

traints)

.make.the.desig

.of.adeq

uate

.rout

ing

.proto

col

.a.major.chal

lenge.

.Besid

es,

.ad.hoc.netw

ork

shou

.be.able.to.prev

ent

.any.atte

mpt

.from.intr

uders

.to.eave

sdrop

.and.jam.the.chan

nel.

.Due.to.open.

P2P.netw

ork

.arch

itecture,

.the.ad.hoc.netw

orks

.are.more.vuln

erable

.agai

nst

.mali

cious

.atta

cks

.than.the.

infr

astructured

.coun

terparts.

. ese.atta

cks

.can.be.acti

.or.passi

ve;

.eith

.an.atta

cker

.acti

vely

.disru

pts

network.operations.or.simply.monitors.data,.controls.trac.patterns,.and.relays.this.information.to.

the.enem

.head

quarters.

. e.secu

rity

.for.ad.hoc.netw

orks,

.ther

efore,

.invo

lves

.key.esta

blishment,

.trus

setu

.secu

.rout

ing,

.auth

entication,

.data.aggr

ession,

.etc.,.and.is.ther

efore

.a.lot.more.chal

lenging

.than.

in.con

ventional

.net

works.

7.1.4 Enabling technologies

IEEE. 802.11. WLAN. [802.11]. is. the. most. popular. technology. for. ad. hoc. networks.. ere. are. vari-

ous

. work

ing

. grou

. for. the. stan

dards

. oer

ing

. high

est

. data. rate. up. to. 54.Mbps. and. enha

ncing

FIGURE 7.2 Vehicular.ad.hoc.networks.

7-4 Industrial Communication Systems

quality-of-service.(QoS).parameters..It.supports.dynamic.frequency.selection,.transmit.power.control,.

and.spec

trum

.and.ener

.mana

gement.

.Besid

.enha

nced

.secu

rity

.meas

ures,

.radi

.reso

urce

.mana

ge-

ment

.is.als

.inc

orporated.

Bluetooth

.[B04

]

.is.a.low-

power

.shor

t-range

.comm

unication

.tech

nology

.desig

ned

.to.conn

ect

.por-

able

.elec

tronic

.devi

ces

.like.phon

es,

.PDAs

.and.keyb

oards.

.When

ever

.two.Blue

tooth-enabled

.devi

ces

come.with

.rang

.of.one.anot

her,

.they.seam

lessly

.esta

blish

.a.smal

.netw

ork.

.Alth

ough

.the.maxi

mum

possi

ble

.data.rate.is.only.1.Mbps

.low-

cost

.and.low-

power

.capa

bilities

.of.Blue

tooth

.have.stim

ulated

.its.

pene

tration

.in.the.mar

ket.

Infrared

.is.a.poin

t-to-point,

.ultr

.low-

power,

.ad.hoc.data.tran

smission

.stan

dard

.desig

ned

.to.oper

ate

over.a.dist

ance

.of.1.m.and.is.exte

ndable

.to.2.m.with.high.powe

.It.can.achi

eve

.data.rate

.up.to.16.Mbps

Infr

ared

.is.chea

per

.than.Blue

tooth

.tech

nology,

.and.both.have.thei

.own.adva

ntages

.and.disa

dvantages.

HomeRF

.is.a.shor

t-range

.comm

unication

.tech

nology

.inte

nded

.for.smal

.area.such.as.home

.or.smal

buil

dings.

.Home

.uses.freq

uency

.hopp

ing

.spre

.spec

trum

.(FHS

.whil

.oper

ating

.at.2.4.GHz.and.

oer

.dat

.rat

.up.to.10.Mbps

ZigBee

.stan

dard

.is.a.shor

t-range

.wire

less

.comm

unication

.stan

dard

.for.PANs

.It.oer

.data.rate.up.

to.250.kbps.at.2.4.GHz,.40.kbps.at.915.MHz,.and.20.kbps.at.868.MHz.with.a.rang

.of.10–1

.m..ZigB

uses.IEEE.802.

15.4

.as.physi

cal

.and.medi

.acce

.cont

rol

.(MAC

)

.laye

rs.

.Uppe

.laye

.as.well.as.ZigB

secu

rity

.arc

hitecture

.are.de

ned

.by.the.Zig

Bee

.sta

ndard.

7.2 Protocol Stack

7.2.1 transport Layer

Transport.layer.protocols.are.responsible.for.end-to-end.delivery.of.data..Transmission.control.protocol.

(TCP

)

.is.a.domin

ant

.tran

sport

.laye

.prot

ocol

.for.wire

.netw

orks.

.TCP.is.resp

onsible

.for.cong

estion

.and.ow.

cont

rol,

.and.reli

able

.and.in-o

rder

.deli

very

.of.pack

ets.

. e.uniq

.char

acteristics

.of.wire

less

.ad.hoc.netw

orks

such.as.lack.of.infra

structure,

.mobi

lity,

.shar

.band

width

.[SAH

S03],

.cont

ention,

.and.high.bit.erro

.rate.

(BER

)

.as.well.as.the.desi

.prin

ciples

.of.TCP.moti

vate

.to.desi

.cust

omized

.tran

sport

.laye

.prot

ocols.

7.2.1.1

Why tCP Doe

s Not Suit

ad Hoc Ne

tworks?

.fai

lure

.of.TCP.to.wor

.wel

.in.ad.hoc.net

works

.is.bec

ause

.of.the.fol

lowing

.kno

.pro

blems:

•

. In. laye

red

.arch

itectures,

. TCP. impl

icitly

.assu

mes

.that. pack

. loss. is.caus

. due. to.coll

isions.

Whereas,.collisions.in.ad.hoc.wireless.networks.are.one.of.the.possible.causes.of.packet.loss,.

alth

ough

.ther

.are.also.othe

.pote

ntial

.caus

.such.as.fadi

ng,

.vary

ing

.link.qual

ity

.[CZW

F04],

inte

rference,

.and.noi

se.

•

. Two.comm

unicating

.node

.as.well.as.othe

.node

.shar

ing

.the.same.medi

.cont

end

.for.the.medi

um.

•

. e.pack

.loss.in.wire

less

.netw

orks

.is.comp

aratively

.high

er,

.and.loss.of.retr

ansmitted

.pack

furt

her

.deg

rades

.the.per

formance.

7.2.1.2

trans

port Layer Protocols for

ad Hoc Ne

tworks

Transport

.laye

.proto

cols

.for.ad.hoc.netw

orks

.can.broa

dly

.be.clas

sied

.into.two.major.appr

oaches

[MK0

4];

.TCP.var

iants

.and.non

-TCP

.var

iants.

.basic.idea.of.TCP.vari

ants

.is.to.reta

.TCP.as.a.tran

sport

.laye

.proto

col,

.beca

use

.of.its.glob

exis

tence,

.and.to.sugg

est

.modi

cations

.in.orde

.to.over

come

.the.prob

lems

.asso

ciated

.with.wire

less

.link

and.mobi

lity.

.TCP.feed

back

.(TCP

-f)

.[F94

]

.is.custo

mized

.in.such.a.way.that.the.send

.is.able.to.die

entiate

.betw

een

.cong

estion

.and.a.lost.link

.In.this.way,.the.invo

cation

.of.cong

estion

.cont

rol

.algo

rithm

is.rest

ricted,

.whic

.in.turn.stops.perf

ormance

.degr

adation.

.In.case.of.link.fail

ure,

.the.send

.node.is.

expl

icitly

.noti

ed

.by.the.netw

ork

.laye

.of.the.neig

hbor

.node

. e.send

.stops.send

ing

.furt

her

.pack

ets,

whil

.all.othe

.node

.list

ening

.to.thes

.noti

cations

.inva

lidate

.thes

.rout

.to.avoi

.pack

.loss

.Expl

icit

Ad Hoc Networks 7-5

link.failure.notication.(ELFN).is.a.technique.similar.to.TCP-f.where.route.failures.are.notied.to.

dow

nstream

.nod

.in.ELF

.mes

sage

.sen

.by.ups

tream

.nod

.of.the.fai

led

.lin

.Ano

ther

.TCP.var

iant

.is.

ad.hoc.TCP.[LS

01]

.whi

.req

uires

.net

work

.lay

.fee

dback

.and.spl

.TCP.[KK

FT02]

.to.dea

.wit

.con

ges-

tion

.co

ntrol

.an

.en

d-to-end

.re

liability

.se

parately.

.the.non

-TCP

.var

iant

.app

roach,

.the.tra

nsport

.lay

.is.bui

.fro

.scr

atch

.whi

.con

sidering

.the.

lim

itations

.of.wir

eless

.ad.hoc.net

works.

.Alt

hough

.thi

.app

roach

.out

performs

.TCP.var

iants

.app

roach

in.a.sta

nd-alone

.env

ironment

.[MK

04,

.p..130

.it.pos

.man

.cha

llenges

.whe

.the.mac

hines

.wit

.suc

tra

nsport

.lay

.hav

.to.tal

.to.the.glo

bal

.Int

ernet.

.Ad.hoc.tra

nsport

.pro

tocol

.(AT

P),

.one.of.the.non

-TCP

var

iants,

.is.spe

cically

.bui

.for.ad.hoc.net

works.

.ATP.exp

loits

.syn

ergies

.bet

ween

.di

erent

.lay

ers

.to.

enh

ance

.per

formance.

.As.men

tioned

.ear

lier,

.one.of.the.dis

advantages

.of.ATP.is.its.inc

ompatibility

.wit

sys

tems

.th

.ar

.ru

nning

.pl

ain

.TC

.rel

iable

.tra

nsport

.pro

tocol

.for.ad.hoc.net

works

.is.sti

.nee

ded.

.Whi

.desi

gning

.a.tra

nsport

.lay

pro

tocol,

.th

.ke

.tr

ade-o

.is.be

tween

.co

mpatibility

.an

.pe

rformance

.of.th

.ne

twork.

7.2.2 Network Layer

Routing.is.used.to.send.the.data.from.source.to.destination.. e.easiest.way.is.to.broadcast.the.data.in.

the.net

work

.tha

.is.was

teful

.of.the.ban

dwidth

.res

ource.

.A.mor

.ec

ient

.way.is.to.com

pute

.rou

.fro

sou

rce

.to.des

tination

.and.sen

.dat

.in.a.mul

tihop

.fas

hion.

. er

.are.di

erent

.way

.to.cla

ssify

.rou

ting

pro

tocols.

. e.rou

ting

.pro

tocols

.can.be.cla

ssied

.on.the.basi

.of.(a).the.way.the.rou

ting

.inf

ormation

.is.

upd

ated,

.(b).net

work

.str

ucture

.(a

.and.hie

rarchical),

.and.(c).posi

tion

.and.non

position-based

.rou

ting

pro

tocols.

. e.di

erent

.ca

tegories

.ar

.di

scussed

.in.th

.fo

llowing

.se

ctions.

7.2.2.1

Pro

active,

react

ive, and Hybrid

rout

ing Protocols

Proactive

.rou

ting

.pro

tocols

.are.als

.kno

.as.tab

le-driven

.pro

tocols.

. e.con

sistent

.and.up-

to-date

rou

ting

.tab

les

.are.com

puted

.ahe

.of.tra

nsmission

.tim

.Whe

never

.topo

logy

.cha

nges,

.upd

ate

.mes

sages

.are.tri

ggered

.to.ass

ure

.con

sistency

.of.net

work

.map.bei

.mai

ntained

.at.eac

.nod

.Des

tination-

sequenced

.dis

tance

.vec

tor

.(DS

DV)

.[PP

94]

.is.a.pro

active

.rou

ting

.pro

tocol,

.whi

.use

.Bel

lman

.For

alg

orithm

.to.com

pute

.the.sho

rtest

.pat

.and.ens

ures

.loo

p-free

.rou

ting

.tab

les.

.Wire

less

.rou

ting

.pro

tocols

(WR

.[MS

GJ96],

.bas

.on.imp

roved

.Bel

lman

.For

.res

trict

.rou

.upd

ates

.to.imm

ediate

.nei

ghbors

onl

. e.clu

ster

.gat

eway

.swi

tch

.rou

ting

.(CG

SR)

.red

uces

.rou

ting

.tab

.size.and.rou

ting

.inf

ormation

exc

hange

.by.emp

loying

.a.clu

stering

.hie

rarchy

.whe

.onl

.the.clu

ster

.hea

.com

municate

.amo

.the

selves.

.Opti

mized

.lin

.sta

.rou

ting

.(OL

SR)

.is.a.dis

tributed,

.tab

le-driven,

.and.pro

active

.rou

ting

.pro

to-

col

.for.mob

ile

.ad.hoc.net

works

.tha

.wor

.on.the.pri

nciple

.of.“mu

ltipoint

.rel

ays,”

.whi

.mea

.sel

ecting

a.set.of.nod

.fro

.wit

hin

.one

-hop

.nei

ghbor

.to.pro

vide

.abi

lity

.to.rea

.all.the.two

-hop

.nei

ghbors.

.OLS

works.well.in.large-scale.and.high-density.network.but.incurs.large.routing.overhead.

Overhead

.of.per

iodic

.upd

ates,

.slo

.rou

.rep

air,

.and.mai

ntenance

.of.unu

sed

.rou

ting

.inf

ormation

are.few.of.the.pro

blems

.of.the.pro

active

.rou

ting

.pro

tocols.

.To.ove

rcome

.the

.iss

ues,

.rea

ctive

.rou

ting

pro

tocols

.ha

.be

.de

signed.

Unlike

.the.pro

active

.rou

ting

.pro

tocols,

.the.rea

ctive

.rou

ting

.pro

tocols

.do.not.mai

ntain

.rou

ting

.tab

les

and.com

pute

.rou

tes

.whe

never

.req

uired.

. es

.are.als

.kno

.as.“on

-demand”

.rou

ting

.pro

tocols.

.Rou

dis

covery

.is.acc

omplished

.by.oo

ding

.req

uest

.in.the.net

work.

.Alt

hough,

.les

.con

trol

.ove

rhead

.mak

the

.sca

lable,

.lar

ger

.del

ays

.are.inc

urred

.whi

.dis

covering

.rou

.whe

never

.nee

ded.

.Dyn

amic

.sou

rce

rou

ting

.(DS

.[DD

96]

.and.ad.hoc.on-

demand

.dis

tance

.vec

tor

.(AO

DV)

.[PR

99]

.are.two.exa

mples

.of.

rea

ctive

.pro

tocols.

.AOD

.is.bas

.on.DSD

.but.is.rea

ctive

.and.loo

.fre

.Tem

porally

.ord

ered

.rou

ting

alg

orithm

.(TOR

.[PC

97]

.is.a.rea

ctive

.sch

eme

.and.is.uni

quely

.fea

tured

.by.mai

ntaining

.mul

tiple

.pat

bet

ween

.gi

ven

.pa

.of.so

urce

.an

.de

stination

.no

des.

 ere

.are.di

erent

.rou

ting

.pro

tocols

.whi

.exh

ibit

.a.hyb

rid

.app

roach

.for.rou

ting,

.for.exa

mple,

.zon

based

.rou

ting

.(ZB

.[DH

Y03].

.ZBR.is.mor

.sui

table

.for.lar

.net

works

.whe

.the.net

work

.is.div

ided

.into.

clusters..Intracluster.routing.is.proactive.while.intercluster.routing.is.reactive.in.ZBR..Other.protocols.

7-6 Industrial Communication Systems

in.this.category.comprise.core.extraction.distributed.ad.hoc.routing.(CEDAR).protocol.[SSB99].and.

zone-based.hierarchical.link.state.(ZHLS).routing.protocol.

7.2.2.2

Flat and Hierarchical routing Protocols

Hierarchical

.routing.protocols.arrange.nodes.in.the.form.of.clusters.or.trees.where.every.cluster.has.a.clus-

ter

.head..Cluster.heads.may.also.aggregate.data.from.cluster.nodes.to.reduce.the.number.of.packet.trans-

missions

.and.hence.conserve.energy.[CPF05].or.may.provide.gateway.to.external.networks..Advantages.

of.hierarchical.routing.protocols.include.scalability.and.ecient.communication.[AK04]..AODV,.DSDV,.

and.DSR.are.examples.of.at.routing.protocols,.while.CGSR.is.an.example.of.hierarchical.routing.scheme.

7.2.2.3

Position- and Nonposition-Based routing Protocols

.is.experimentally.veried.that.reactive.and.proactive.routing.protocols,.including.AODV,.DSDV,.and.DSR.

that.do.not.use.location.information.in.routing.decisions,.face.scalability.issues.as.opposed.to.location-based.

routing.strategies.[S02]..Location-based.routing.depends.upon.the.physical.position.of.the.nodes.in.the.net-

work

.to.take.routing.decisions.[MWH01]..To.get.location/position.information,.the.node.may.use.a.low-

power

.global.positioning.system.(GPS).if.the.nodes.are.outdoor.or.may.rely.on.relative.positioning.techniques.

based.on.the.signal.strength.or.manual.registration.process..Several.position-based.routing.schemes.[SL01].

have.already.been.presented.by.the.research.community..Position-based.routing.algorithms.are.classied.into.

greedy.and.restricted.directional.ooding..In.greedy.approaches,.the.distance.toward.the.sink.node.is.either.

maximized.or.minimized.depending.upon.forwarding.strategy,.while.in.directional.ooding,.the.data.are.

always.ooded.toward.the.nodes.which.are.in.the.direction.of.the.destination.node..Greedy.perimeter.state-

less

.routing.(GPSR).[KK00].and.geographic.distance.routing.(GEDIR).[SL01].are.examples.of.position-based.

routing.protocols.working.on.the.principle.of.greedy.forwarding.approach.

7.2.3 MaC Layer

MAC.schemes.are.used.to.dene.policy.for.accessing.the.shared.medium.in.ad.hoc.networks..Limited.

spectrum,. multiple.access,. node.mobility,. error-prone. environment,. and. characteristics. of. wireless.

medium.like.noise,.fading,.and.interference.compel.to.design.MAC.schemes.customized.for.wireless.

environments.. e.MAC.schemes.for.ad.hoc.networks.can.be.classied.into.contention-free.and.con-

tention-based

.protocols..Contention-free.protocols.work.better.in.infrastructure-driven.networks.with.

a.master.node.controlling.the.medium.access..Contention-based.protocols.work.in.a.decentralized.fash-

ion

.and.can.be.divided.into.random.access.and.controlled.access.(scheduling-.and.reservation-based).

protocols.. e.performance.of.such.protocols.is.deteriorated.by.hidden.and.exposed.terminal.problems.

and.requires.special.attention.

Let

.us.assume.that.node-1.is.sending.data.to.node-2,.as.shown.in.Figure.7.3..Furthermore,.assume.

that.node-3.is.also.about.to.send.data.to.node-2..As.node-3.is.out.of.the.transmission.range.of.node-1,.

Range of 1 Range of 2 Range of 3

1 2 3 4

FIGURE 7.3 Hidden.and.exposed.terminal.problem.

Ad Hoc Networks 7-7

it.will.sense.the.medium.as.free.and.sends.data.to.node-2.which.will.result.in.a.collision.. is.is.known.as.

hid

den

.ter

minal

.pro

blem;

.nod

e-1

.and.nod

e-3

.are.hid

den

.fro

.eac

.oth

er.

. is.iss

.is.sol

ved

.by.req

uest-

to-send/clear-to-send

.(RT

S/CTS)

.mec

hanism.

.Now

.ass

ume

.tha

.nod

e-3

.kno

.by.RTS

/CTS

.mec

hanism

tha

.nod

e-1

.and.nod

e-2

.are.com

municating;

.it.wil

.ref

rain

.fro

.com

municating

.wit

.nod

e-4

.as.wel

tho

ugh

.nod

e-4

.is.bey

ond

.the.ran

.of.nod

e-2

.and.thu

.cha

nnel

.cap

acity

.wil

.be.unn

ecessarily

.was

ted.

 is.is.kn

own

.as.ex

posed

.te

rminal

.pr

oblem.

7.2.3.1

and

acce

ss Schemes

.ran

dom

.acc

ess

.sch

emes

.(al

.kno

.as.con

tention-based

.sch

eme),

.nod

.con

tend

.for.the.sha

red

cha

nnel

.wit

.the.nei

ghboring

.nod

.(no

des

.wit

hin

.int

erference

.ran

ge)

.and.the.win

ning

.nod

.get.

hol

.of.the.med

ium.

.Suc

.sch

emes

.can

not

.gua

rantee

.QoS.bec

ause

.acc

ess

.to.the.cha

nnel

.is.not.gua

anteed

.and.is.ran

dom.

.In.ALO

.[N7

0],

.a.nod

.sim

ply

.sen

.dat

.as.soo

.as.it.is.ava

ilable.

.Slo

tted

ALO

.int

roduces

.tim

.div

ision

.mul

tiple

.acc

ess

.(TD

MA)–like

.tim

e-slots

.to.red

uce

.the.num

ber

.of.

col

lisions.

.Car

rier

.sen

.mul

tiple

.acc

ess

.(CS

MA)–based

.sch

emes

.fur

ther

.enh

ance

.the.per

formance

.by.

car

rier

.sen

.mec

hanism.

. e.per

formance

.of.all.suc

.sch

emes

.is.adv

ersely

.ae

cted

.by.hid

den

.and.

exp

osed

.ter

minal

.pro

blem.

7.2.3.2

ese

rvation-Driven Contention-Based

acce

.ord

.to.ove

rcome

.the.pro

blems

.of.hid

den

.and.exp

osed

.ter

minal

.pro

blems,

.dyn

amic

.rese

rvation-based

protocols.are.designed,.which.operates.on.the.basis.of.RTS/CTS.mechanism..In.such.protocols,.a.node.

ini

tiates

.the.rese

rvation

.pro

cess

.if.it.has.some.dat

.to.send

. e.send

ing

.nod

.send

.an.RTS.pac

ket

.to.the.

nex

.hop

. e.nex

.hop.in.tur

.rep

lies

.by.a.CTS.mes

sage.

.Suc

.a.CTS.is.hea

.by.oth

.nod

.in.the.vic

in-

ity,

.and.the

.kee

.qui

.unl

ess

.the.dat

.are.act

ually

.sent.by.the.ini

tiating

.nod

.MAC.lay

.de

ned

.by.IEE

802

.11

.sta

ndard

.inc

ludes

.dis

tributed

.coo

rdination

.fun

ction

.(DCF

)

.and.poi

.coo

rdination

.fun

ction

.(PC

F).

DCF.is.based.on.CSM

A/CA

.and.uses.RTS

-CTS-DATA-ACK

.mech

anism

.for.dat

.tra

nsmission,

.whi

.PCF.

is.des

igned

.for.inf

rastructure-based

.net

works.

.Oth

.imp

ortant

.pro

tocols

.in.thi

.cat

egory

.inc

ludes

.mul

tiple

.acce

.col

lision

.avo

idance

.(MA

CA)

.[K9

0],

.MAC

.for.wir

eless

.LAN

.(MA

CAW)

.[BD

SZ94],

.and.oo

acq

uisition

.mul

tiple

.acce

.(FA

MA)

.[FG

95],

.whi

.are.all.based.on.CSM

A/CA.

7.2.3.3

Sch

eduling-Driven Contention-Based

acce

Such

.pro

tocols

.are.desi

gned

.to.pro

vide

.a.cer

tain

.lev

.of.QoS

.Sch

eduling

.can.be.a.fun

ction

.of.di

erent

par

ameters,

.for.exa

mple,

.rem

aining

.nod

.ene

rgy,

.tra

c

.loa

ds,

.and

/or

.bou

.on.pac

ket

.del

ays.

.Som

of.the.sch

eduling-driven

.MAC.sch

emes

.inc

lude

.dis

tributed

.pri

ority

.sch

eduling

.and.med

ium

.acc

ess

[KL

SSK02]

.an

.di

stributed

.la

xity-based

.pr

iority

.sc

heduling

.sc

heme

.[K

MS05].

7.2.4 Physical Layer

Physical.layer.translates.communication.requests.from.the.upper.layers.into.hardware-specic.opera-

tions

.to.ena

ble

.tra

nsmission

.or.rec

eption

.of.sign

als.

. es

.ope

rations

.nor

mally

.inv

olve

.tim

.and.fre

quency

.syn

chronization

.whi

.als

.dea

ling

.wit

.har

.tim

.var

iant

.and.fre

quency-selective

.wir

eless

cha

nnels.

.Besi

des,

.the.per

formances

.can.be.sev

erely

.com

promised

.by.int

erference

.ori

ginating

.fro

oth

.ter

minals

.ope

rating

.on.non

orthogonal

.res

ources,

.the

reby

.req

uiring

.ec

ient

.rec

eive

.str

ategies

whi

.giv

.goo

.com

plexity

.per

formance

.tra

de-o.

.Her

.we.giv

.an.ove

rview

.of.phy

sical

.lay

.spe

ci-

cation

.for.onl

.two.mai

.sta

ndards

.sup

porting

.ad.hoc.wir

eless

.net

works,

.i.e

.the.IEE

.802

.11

.sta

dard

.for.WLA

.[80

2.11]

.and.the.Blu

etooth

.spe

cications

.for.sho

rt-range

.wir

eless

.com

munications

[B0

1,FBP98].

. e.rs

.one.not.onl

.all

ows

.sin

gle-hop

.WLA

.ad.hoc.net

work

.but.can.also.be.ext

ended

.to.

mul

tihop

.net

works

.cov

ering

.are

.of.sev

eral

.squ

are

.kil

ometers,

.whi

.the.sec

ond

.one.can.onl

.be.use

to.bu

ild

.sm

aller

.sc

ale

.ad.ho

.wi

reless

.bo

.an

.PA

Ns.

IEEE

.802

.11

.is.the.rs

.wir

eless

.loc

.are

.net

work

.sta

ndard

.wit

.dat

.rat

.of.up.to.2.Mbp

.[80

2.11].

 e.ori

ginal

.sta

ndard

.has.the

.bee

.ext

ended

.to.802

.11b,

.802

.11a,

.and.802

.11g

.whi

.ope

rate

.in.the.

7-8 Industrial Communication Systems

2.4.and.5.GHz.unlicensed.band.. e.peak.data.rates.of.11.Mbps.are.supported.by.802.11b.and.54.Mbps.

for.802.

11a

.and.802.

11g.

.Die

rent

.tran

smission

.tech

nologies

.such.as.infr

ared,

.orth

ogonal

.freq

uency

doma

.mult

iplexing

.(OFD

M),

.FHSS

.and.dire

.sequ

ence

.spre

.spec

trum

.(DSS

.can.be.empl

oyed.

For.any.give

.band

width,

.thes

.stan

dards

.supp

ort

.die

rent

.data.rate

.by.sele

cting

.die

rent

.modu

la-

tion

.sche

mes,

.i.e.,.DBPS

.DQPS

.16-Q

AM,

.etc..Besid

es,

.half.rate.conv

olution

.code

.are.used.with.

punc

turing

.to.ensu

.reli

able

.data.tran

sfer

.for.a.give

.QoS..Sync

hronization

.is.achi

eved

.by.send

ing

.a.

pred

ened

.sequ

ence

.whic

.aler

.the.rece

iver

.that.a.signa

.is.pres

ent.

. is.is.foll

owed

.by.star

.fram

deli

miter

.whic

.den

.the.begi

nning

.of.a.fram

. e.next.gene

ration

.for.802.

.is.802.

11n,

.whic

.is.

desig

ned

.to.ee

ctively

.rep

lace

.all.the.pre

vious

.802

.11

.sta

ndards

.and.ena

bles

.spe

.up.to.540.Mbps

.Blue

tooth

.tech

nology

.is.the.comm

only

.adopt

.stan

dard

.for.low-

cost,

.shor

t-range

.radi

.link

betw

een

.die

rent

.port

able

.devi

ces

.[MB0

0].

.Also

.base

.on.the.port

ions

.of.the.Blue

tooth

.spec

ication,

the.IEEE.802.

.has.been.put.forw

ard

.as.a.WPAN.stan

dard.

.Like.802.

11,

.the.Blue

tooth

.syst

.is.oper

ating

.in.the.2.4.GHz.indu

strial,

.scie

ntic,

.and.medi

cine

.band.(ISM

. e.modu

lation

.uses.Gaus

sian

freq

uency

.shi.keyi

.(GFS

.with.a.maxi

mum

.freq

uency

.devi

ation

.of.140–

175

.kHz.. e.tran

smission

tech

nology

.adopt

.is.FHSS

.wher

.hopp

ing

.at.up.to.1600.hops

.amon

.79.chan

nels,

.whic

.are.spac

at.1.MHz.sepa

ration.

. e.maxi

mum

.tran

smission

.powe

.depe

nds

.upon.whic

.of.the.thre

.powe

.clas

ses

(as.den

.by.the.stan

dard)

.are.supp

orted

.and.rang

.from.1.to.100.mW..A.maxi

mum

.base

-band

.data.

rate.of.723.

.kbps.is.supp

orted

.for.each.link

.with.optio

.for.1/3.rate.repe

tition

.and.2/3.rate.Hamm

ing

forw

ard

.err

.cor

rection

.cod

es.

7.3 Performance Evaluation

Traditionally,.the.performance.evaluation.of.ad.hoc.networks.has.been.done.on.a.layer-by-layer.basis..

New.proto

cols

.are.prop

osed

.at.a.cert

ain

.laye

.and.perf

ormance

.stud

ies

.comp

are

.them.with.one.anot

her

for.a.numbe

.of.scen

arios

.and.vary

ing

.cond

itions.

. e.key.issu

.in.the.desig

.and.perf

ormance

.of.

MANE

.are.comp

rehensively

.pres

ented

.in.the.auth

oritative

.refe

rence

.[CCL

03].

.Scor

.of.stud

ies

.com-

are

.MAC.proto

cols

.for.both.rand

.acce

.and.rese

rvation-based

.sche

mes

.for.use.in.ad.hoc.wire

less

netw

orks

.pres

enting

.nove

.idea

.Simi

larly

.at.the.netw

ork

.laye

.the.perf

ormance

.eval

uation

.of.a.numbe

of.rout

ing

.prot

ocols

.for.a.vari

ety

.of.work

load

.scen

arios

.has.been.simu

lated

.[B04

.More.rece

.and.

comp

rehensive

.simul

ation

.resu

lts

.using.OPNE

.Mode

ler

.10.5.[IR1

]

.have.been.carr

ied

.out.for.the.most.

comm

only

.used.rout

ing

.proto

cols,

.for.inst

ance

.AODV

.DSR,.and.TORA.[AA0

6].

.Simi

larly,

.the.per-

ormance

.of.tran

sport

.laye

.proto

cols

.over.MANE

.has.been.consi

dered

.in.a.numbe

.of.stud

ies

.and.

sche

mes

.such.as.dela

ying

.ACKs.[CGL

S08]

.or.using.a.frac

tional

.wind

.incr

ement

.(FeW

)

.have.been.

rece

ntly

.pres

ented

.[WHX

09].

.In.the.same.vein

.the.impa

.of.P2P.tra

.on.vari

ous

.rout

ing

.proto

cols

in.MANE

.has.been.eval

uated

.in.[OSL

05].

.A.consi

deration

.that.cuts.acro

.all.stud

ies

.is.the.choi

of.the.mobi

lity

.mode

.Most.stud

ies

.assu

.a.rand

.way.poin

.mobi

lity

.mode

.whic

.may.not.be.the.

most.appr

opriate

.mode

.for.ad.hoc.netw

orks.

.A.comp

rehensive

.fram

ework

.for.eval

uating

.the.impa

.of.

mobi

lity

.in.ad.hoc.netw

orks

.is.pres

ented

.in.[BSH

03],

.and.more.rece

.stud

ies

.have.eval

uated

.the.impa

of.the.mobi

lity

.mode

.on.rout

ing

.proto

cols

.[TBD

07].

.A.furt

her

.consi

deration

.espe

cially

.for.sens

.net-

orks

.is.ener

.eci

ency,

.and.a.numbe

.of.stud

ies

.pres

ent

.ener

gy-ecient

.sche

mes

.both.at.the.MAC.

and.at.the.net

work

.lay

.in.ord

.to.inc

rease

.nod

.lif

.performance.modeling.of.ad.hoc.networks.is.a.complex.problem,.primarily.due.to.the.fact.that.

the.rese

arch

.comm

unity

.does.not.have.a.uni

.fram

ework

.for.unde

rstanding

.the.inte

raction

.of.MAC.

laye

.cong

estion,

.inte

rference,

.netw

ork

.codi

ng,

.and.reli

ability

.[KHP

08].

. e.perf

ormance

.eval

uation

of.ad.hoc.netw

orks

.is.furt

her

.comp

ounded

.by.the.choi

.of.the.mobi

lity

.mode

.as.well.as.by.the.traf

c

.patt

erns

.[PDH

07],

.wher

ein

.it.has.been.demo

nstrated

.that.the.choi

.of.more.repr

esentative

.tra

patt

erns

.migh

.prod

uce

.resu

lts

.that.are.die

rent

.than.trad

itional

.choi

ces

.of.tra

.sour

ces.

.Cros

s-layer

desig

.have.been.a.major.them

.and.nove

.stac

.have.been.prop

osed

.to.impr

ove

.the.perf

ormance

.of.

ad.hoc.and.sens

.netw

orks.

.Unde

rstanding

.the.role.and.inte

ractions

.betw

een

.each.subc

omponent

.will.

impr

ove

.our.und

erstanding

.of.the

.com

plex

.dis

tributed

.sys

tems.

Ad Hoc Networks 7-9

7.4 Challenges and Issues

7.4.1 Quality-of-Service

With.the.increase.in.portable.computing.devices.and.demand.for.multimedia.applications,.the.impor-

tance

.of.prov

iding

.QoS.in.ad.hoc.netw

orks

.will.cert

ainly

.grow

. ere.are.two.key.chal

lenges

.in.prov

id-

ing

.QoS.over.ad.hoc.netw

orks:

.the.ckl

.natu

.of.the.radi

.chan

nel

.and.the.mobi

lity

.of.the.node

 e.vary

ing

.qual

ity

.of.the.tran

smission

.chan

nel

.due.to.inte

rference

.and.fadi

.resu

lts

.in.dyna

mically

chan

ging

.BERs.and.band

width

.thro

ughput

.as.well.as.prob

lems

.for.the.netw

ork

.laye

.in.dist

inguishing

betw

een

.cong

estion

.or.link

-layer

.loss

.Furt

hermore,

.it.is.dic

ult

.to.appl

.conv

entional

.tech

niques

.that.

esti

mate

.the.eec

tive

.band

width

.at.a.node.for.prov

iding

.QoS.in.orde

.to.ensu

.band

width

.rese

rvation,

admi

ssion

.cont

rol,

.poli

cing,

.and.ow.cont

rol

.in.ad.hoc.netw

orks.

. e.surv

.pape

.by.[KRD

06]

.and.

[RKM

M06]

.prov

ide

.an.exce

llent

.over

view

.to.the.issu

.and.chal

lenges

.by.prov

iding

.a.laye

r-wise

.clas

sication

.and.QoS.fram

eworks

.for.ad.hoc.netw

orks.

.QoS.over.mult

ihop

.netw

orks

.pose

.furt

her

.chal

lenges

.as.each.node.may.be.forw

arding

.mult

iple

.ows.of.vary

ing

.dema

nds

.[MRV

09].

.Rece

.adva

nces

.in.

mult

iple

.inpu

.mult

iple

.outp

.(MIM

.tech

nology

.have.led.to.a.grow

ing

.inte

rest

.in.mult

iantenna

.wire

less

.ad.hoc.netw

orks

.wher

.each.node.has.more.than.one.ante

nna.

. e.adva

nces

.in.MIMO.tech

nology

resu

.in.signi

cant

.gain

.in.link.capa

city

.whil

.comba

ting

.mult

iple

.path.inte

rference

.and.mult

iple-user

inte

rference,

.mak

ing

.cro

ss-layer

.app

roaches

.to.pro

viding

.QoS.att

ractive

.[GL

B09].

7.4.2 Energy Management

Since. ad. hoc.wireless. networks. are.mostly.collection. of. battery-operated. portable. devices,. ecient.

ener

.mana

gement

.is.crit

ical.

. ese.netw

orks

.oer.comm

unication

.using.inte

rmediate

.mobi

.host

.to.

rout

.info

rmation,

.seve

rely

.stra

ining

.thei

.alre

ady

.limi

ted

.powe

.Addi

tionally,

.in.wire

less

.sens

.net-

orks,

.many.devi

ces

.are.oper

ated

.by.batt

eries

.that.cann

.be.repl

aced

.at.all.. ere

fore,

.ener

gy-ecient

desig

.are.requ

ired

.for.thes

.devi

ces

.to.enab

.them.to.oper

ate

.for.prol

onged

.peri

.of.time.with

out

.repl

acing

.batt

eries.

. e.powe

r-conservative

.sche

mes

.are.clas

sied

.into.tran

smitter

.powe

r-control

mech

anisms

.and.pow

er-management

.alg

orithms.

Power

. cont

rol

. invo

lves

. cont

rolling

. the. host. tran

smission

. powe

. in. acco

rdance

. with. dist

ances

betw

een

.the.term

inals

.so.that.any.requ

ired

.crit

erion

.for.the.rece

ived

.powe

.can.be.sati

sed.

.In.[RR0

0],

two.cent

ralized

.algo

rithms

.are.prop

osed

.whic

.outp

.the.tran

smission

.powe

.of.each.host.by.con-

tructing

.eith

.a.uni-

connected

.netw

ork

.or.a.bi-c

onnected

.netw

ork.

.Alth

ough

.thes

.algo

rithms

.are.

desig

ned

.for.stat

.netw

orks

.wher

.loca

tion

.of.all.host

.is.know

.they.allo

.a.cont

inuous

.adju

stment

of.the.host.tran

smission

.powe

.to.main

tain

.a.cert

ain

.QoS.. ese.algo

rithms,

.howe

ver,

.requ

ire

.a.guar

anteed

.know

ledge

.of.glob

.conn

ectivity

.with

out

.whic

.they.may.lead.to.a.disc

onnected

.netw

ork.

. is.

glob

.netw

ork

.conn

ectivity

.is.ensu

red

.in.[WLB

W01],

.whic

.assu

mes

.that.each.rece

iver

.is.able.to.dete

mine

.the.dir

ection

.of.the.sen

der

.whe

.rec

eiving

.a.mes

sage.

Power-management

.stra

tegies

.are.appl

ied

.to.MAC.or.high

.laye

.of.OSI.mode

. e.powe

.cons

ump-

tion

.of.host

.in.ad.hoc.netw

orks

.stro

ngly

.depe

nds

.on.the.MAC.poli

.[WES

W98].

.In.[BCD

99,BCD01],

the.auth

ors

.prop

ose

.a.dist

ributed

.cont

ention

.cont

rol

.(DCC

)

.prot

ocol,

.whic

.preem

ptively

.esti

mates

.the.

probability.of.successful.transmission.before.transmitting.each.frame.and.defers.transmission.if.

the.prob

ability

.of.succ

ess

.is.too.low.. us,.batt

ery

.ener

.is.save

.by.avoi

ding

.unne

cessary

.retr

ansmis-

sions,

.whic

.cons

ume

.signi

cant

.powe

.In.[RS9

8],

.a.powe

r-aware

.mult

iaccess

.proto

col

.with.signa

ling

(PAM

AS)

.is.intr

oduced

.for.powe

.cons

ervation

.in.ad.hoc.netw

orks,

.whic

.prop

oses

.sepa

rate

.data.and.

signa

ling

.chan

nels.

. e.signa

ling

.chan

nel

.is.used.for.exch

anging

.RTS/

CTS

.pack

ets

.whic

.enab

les

.a.host.

to.dete

rmine

.when.and.for.how.long.to.powe

.its.ante

nna

.o..Simi

larly,

.seve

ral

.powe

r-saving

.tech

niques

are.prop

osed

.[CT0

0,SL01]

.for.the.netw

ork

.laye

.for.ad.hoc.netw

orks.

.For.rout

.sele

ction,

.thes

.proto

cols

not.only.take.into.acco

unt

.the.trad

itional

.rout

ing

.proto

col

.metr

ics

.such.as.hop-

count,

.link.qual

ity,

.and.

congestion.but.also.consider.battery.power.levels..Power-management.protocols.are.also.implemented.

7-10 Industrial Communication Systems

for.transport.layer.where.the.TCP.is.modied.to.respond.appropriately.to.unreliable.wireless.environ-

ment

.by.avo

iding

.ret

ransmission

.and.ee

ctive

.con

gestion

.con

trol

.[KK

98].

.In.add

ition,

.pow

er-ecient

str

ategies

.are.als

.sug

gested

.for.the.app

lication

.lay

.whe

.the.ope

rating

.sys

tem

.(OS

)

.is.mod

ied

.to.

han

dle

.th

.ha

rdware

.an

.so

ware

.mo

.e

ciently

.[L

S98].

7.4.3 topology and Connectivity

In.most.of.the.ad.hoc.networks,.P2P.communication.topology.is.required,.which.means.each.node.in.

the.net

work

.mus

.be.abl

.to.com

municate

.wit

.any.oth

.nod

.in.the.sam

.net

work.

.To.att

ain

.thi

con

nectivity

.bet

ween

.the.ent

ire

.net

works

.mus

.be.pro

vided

.all.the.tim

es.

.But.the.lim

ited

.res

ources,

unc

ontrolled

.mob

ility

.of.nod

es,

.and.the.cha

racteristics

.of.wir

eless

.com

munication

.cha

nnels

.mak

.it.a.

cha

llenging

.iss

ue.

.Top

ology

.and.con

nectivity

.con

trol

.can.hav

.a.sign

icant

.imp

act

.on.the.per

formance

of.wir

eless

.net

works.

.Suc

.alg

orithms

.are.use

.to.enh

ance

.ene

rgy

.ec

iency,

.min

imize

.int

erference,

.and.

inc

rease

.e

ective

.ra

.by.ad

justing

.tr

ansmission

.po

wer.

Topology

.con

trol

.alg

orithms

.can.be.cat

egorized

.into.cen

tralized

.and.dis

tributed

.[SB

C03].

.Cen

tralized

app

roach

.nee

.to.hav

.the.glo

bal

.kno

wledge

.of.the.net

work

.and.wor

.wel

.in.sta

tic

.net

works.

.Dis

tributed

app

roach

.use

.loc

alized

.inf

ormation

.onl

.and.wor

.wel

.in.mob

ile

.net

works.

. er

.are.man

.iss

ues

wit

.topo

logy

.con

trol

.alg

orithms.

.Opti

mal

.tra

nsmit

.pow

.com

putation

.is.one.of.the.mai

.cha

llenges.

If.hig

.tra

nsmit

.pow

.is.use

.int

erference

./co

ntention

.ran

.is.inc

reased.

.If.low

.pow

.is.use

.it.may.

res

ult

.in.a.dis

connected

.net

work.

.Fur

thermore,

.adj

usting

.pow

.lev

.may.int

roduce

.add

itional

.lat

ency.

In.cen

tralized

.app

roach,

.whe

.all.the.inf

ormation

.is.sen

.to.a.cen

tral

.aut

hority,

.red

ucing

.pro

cessing

.and.

com

munication

.ove

rhead

.is.a.cha

llenging

.tas

.Ec

ient

.topo

logy

.con

trol

.alg

orithms

.whi

.tak

.nod

mob

ility

.in

.ac

count

.st

ill

.re

quire

.a.gr

eat

.de

.of.at

tention.

7.4.4 Security

Security.is.required.for.secure.communication.and.to.maintain.desired.network.performance.in.ad.

hoc.net

work

.[YL

YLZ04].

.Sec

urity

.iss

ues

.in.ad.hoc.net

works

.are.mor

.cha

llenging

.tha

.in.con

ven-

tional

.net

works

.bec

ause

.of.ope

.acc

ess

.mec

hanism

.and.P2P.arc

hitecture,

.no.inf

rastructure,

.hig

hly

dyn

amic

.net

work

.top

ology,

.pub

licly

.kno

.pro

tocols,

.str

ingent

.res

ource

.con

straints,

.and.una

ttended

ope

ration.

Security

.for.ad.hoc.net

works

.ent

ails

.key.est

ablishment

.and.tru

.set

up,

.sec

recy

.and.aut

hentication,

pri

vacy,

.sec

ure

.rou

ting,

.int

rusion,

.and.sec

ure

.dat

.agg

regation

.[PS

W04].

. re

.mai

.goa

.of.sec

urity

as.dis

cussed

.in.[DP

T03]

.are.to.mai

ntain

.con

dentiality

.(da

.pro

tection),

.int

egrity

.(un

authorized

.dat

tam

pering),

.and.ava

ilability

.(se

rvice

.ava

ilability

.any

where

.and.any

time).

.Com

mon

.sec

urity

.thr

eats

.out

lined

.in.[PS

S00]

.and.dis

cussed

.in.[DP

T03]

.inc

lude

.“st

ealing

.con

dential

.inf

ormation,

.tam

pering

.inf

or-

mation,

.re

source

.st

ealing,

.an

.de

nial-of-

.se

rvice

.at

tacks.”

Following

.is.the.sum

mary

.of.the.ope

.res

earch

.opp

ortunities

.and.cha

llenges

.in.the.sec

urity

.imp

le-

mentation

.for.ad.hoc.net

works,

.whi

.are.dis

cussed

.in.[ZF

Z08,R96,RFLW96].

.Bec

ause

.of.the.wir

eless

env

ironment

.and.lac

.of.re

wall-like

.dev

ices,

.the.eav

esdroppers

.can.spo

.the.ong

oing

.com

munica-

tion

.tha

.com

promises

.con

dentiality,

.pri

vacy,

.and.int

egrity

.of.dat

.On.the.net

work

.lay

er,

.mal

icious

nod

.can.int

roduce

.den

ial-of-service

.att

acks,

.hol

es,

.and.tam

per

.inf

ormation

.com

promising

.bas

sec

urity

.pri

mitives,

.for.exa

mple,

.ava

ilability

.and.int

egrity

.of.dat

. er

efore,

.des

igning

.sec

ure

.rou

ing

.pro

tocols

.is.one.of.the.cha

llenging

.are

.in.ad.hoc.net

works.

.[T9

.and.[SM

G97]

.are.a.few.eo

rts

in.thi

.dir

ection.

. e.maj

.cha

llenge

.is.the.aut

hentication

.of.the.pub

lic

.key

.whi

.can.be.sol

ved

.by.

using.identity-based.cryptography..As.the.security.operations.are.very.frequent.in.ad.hoc.networks,.

it.req

uires

.an.ec

ient

.sym

metric

.key.alg

orithm

.for.aut

hentication

.and.enc

ryption.

.Key.rev

ocation

sho

uld

.hap

pen

.whe

.a.nod

.is.dec

lared

.as.mal

icious

.or.whe

.it.is.und

.com

promise

.nod

.att

ack.

Alt

hough

.di

erent

.key.rev

ocation

.sch

emes

.are.wor

king,

.sti

.the

.is.a.dem

and

.for.uni

versal

.key.

rev

ocation

.sch

eme

.[ZF

Z08].

Ad Hoc Networks 7-11

references

[802.11].IEEE standard for Wireless LAN Meduim Access Control: MAC and PHY Specications,.ISO/IEC.

8802-11,.1999(E),.1999.

[AA06]

.S..Ahme

.and.M..S..Ala

.Perf

ormance

.eval

uation

.of.impo

rtant

.ad-hoc.netw

ork

.pro

tocols,

EURAS

IP Journal on Wireless Communications and Networking,

.1–11,.2006.

[AK04]

.J..N..Al-Ka

raki

.and.A..E..Kam

al,

.Rou

ting

.tec

hniques

.in.wire

less

.sens

.netw

orks:

.A.surv

ey,

.IEEE

Wir

eless Communications,

.11,.6–28,.2004.

[B01]

.C..Bis

dikian,

.An.over

view

.of.the.bluet

ooth

.wire

less

.tec

hnology,

.IEEE Co

mmunication Magazine,

Decem

ber

.2001.

[B04]

.A..Bou

kerche,

.Perf

ormance

.eval

uation

.of.rou

ting

.pro

tocols

.for.ad-hoc.wire

less

.netw

orks,

.Jou

rnal of

Mobile Networks and Applications,

.9,.333–342,.2004.

CD01]

.L..Bon

oni,

.M..Con

ti,

.and.L..Don

atiello,

.A.dis

tributed

.mec

hanism

.for.pow

.sav

ing

.in.IEE

.802

.11

Wir

eless

.LAN

.ACM

Journal of Mobile Networks and Applications (MONET),

.6,.211

–222,

.200

[BCD99]

.L..Bon

oni,

.M..Con

ti,

.and.L..Don

atiello,

.A.dis

tributed

.con

tention

.con

trol

.mec

hanism

.for.pow

sav

ing

.in.ran

dom-access

.ad-

hoc

.wir

eless

.loc

.are

.net

works,

.in.IEE

E International Workshop on

Mobile Multimedia Communications (MoMuC),

.San.Die

go,

.CA,.pp..114

–123,

.Nov

ember

.15–

17,

.199

[BDSZ94]

.V..Bha

rgavan,

.A..Demer

.S..Shen

ker,

.and.L..Zhan

.MACAW

.A.medi

.access.pro

tocol

.for.

wire

less

.LAN

.ACM S

IGCOMM Computer Communication Review,

.24(4),.212–225,.1994.

[BSH03]

.F..Bai

.N..Sadag

opan,

.and.A..Helm

. e.IMPORT

ANT

.fram

ework

.for.ana

lyzing

.the.Imp

act

.of.

Mob

ility

.on.Perf

ormance

.Of.RouT

ing

.pro

tocols

.for.Adh

.NeTw

orks,

.Jou

rnal of Ad-Hoc Networks,

1,.383–403,.2003.

[CCL03]

.I..Chl

amtac,

.M..Con

ti,

.and.J..J.-N..Liu

.Mob

ile

.ad-hoc.netw

orking:

.Imp

eratives

.and.cha

llenges,

Jou

rnal of Ad-Hoc Networks,

.1,.13–64,.2003.

[CGLS08]

.J..Chen,.M..Gerl

.Y..Z..Lee

.and.M..Y..Sanadidi

.TCP.wit

.dela

yed

.ACK.for.wire

less

.netw

orks,

Jou

rnal of Ad-Hoc Networks,

.6,.1098–1116,.2008.

[CPF05]

.K..S..Cha

.H..Pis

hro-Nik,

.and.F..Fek

ri,

.Ana

lysis

.of.hierarc

hical

.algo

rithms

.for.wire

less

.sens

netw

ork

.rou

ting

.pro

tocols,

.IEEE Wi

reless Communications and Networking Conference,

.3,.13–17,.

Mar

.2005.

[CT00]

.J.-H..Cha

.and.L..Tas

siulas,

.Energ

.cons

erving

.rou

ting

.in.wire

less

.ad-hoc.netw

orks,

.in.19th

nual Joint Conference of the IEEE Computer and Communications Societies (INFOCOM),

.vol

.1,.

Tel-A

viv,

.Israe

.pp

.22–31,.Ma

rch

.2000.

[CZWF04]

.X..Chen,.H..Zhai

.J..Wan

.and.Y..Fan

.TCP.perf

ormance

.over.mob

ile

.ad-hoc.netw

orks,

Can

adian Journal of Electrical and Computer Engineering,

.29,.129–134,.2004.

[DD96]

.D..B..John

son

.and.D..A..Mal

tz,

.Dyn

amic

.sour

.rou

ting

.in.ad.hoc.wire

less

.netw

orks,

.in.Mob

ile

Computing,

.Kl

uwer,

.Bos

ton,

.MA,.1996.

PT03]

.D..Die

trich,

.P..Pal

ensky,

.and.A..Tre

ytl,

.Com

munication

.in.aut

omation

.wit

.the.emp

hasis

.on.sec

rity,

.in.EUSAS (European Society for Automatic Alarm Systems) Workshop,.Rome,.Italy,.pp..89–104,.

Jun

.16–

17,

.200

[F94]

. S.. Floyd

. TCP. and. explicit. cong

estion

. not

ication,

. ACM J

ournal of SIGCOMM Computer

Communication Review,

.24,.8–23,.1994.

[FBP98]

.M..Falo

utsos,

.A..Ban

erjea,

.and.R..Pan

kaj,

.QoSMI

.Qua

lity

.of.serv

ice

.sensi

tive

.mul

ticast

.Int

ernet

Pro

tocol,

.SI

GCOMM Computer Communication Rev.

.28(4),.144–153,.1998.

[FG95]

.C..L..Fu

llmer

.an

.J..J..Gar

cia-Luna-Aceves,

.Floo

.acqui

sition

.mu

ltiple

.access.(FAMA).fo

.pac

ket-

radio

.net

works,

.ACM S

IGCOMM Computer Communication Review,

.25,.262–273,.1995.

[GLB09]

.R..Guima

rães,

.L..Cerd

à,

.J..M..Bar

celó,

.J..Garcí

.M..Voo

rhaen,

.and.C..Blon

dia,

.Qua

lity

.of.ser-

ice

.thro

ugh

.ban

dwidth

.reser

vation

.on.mul

tirate

.ad-hoc.wire

less

.netw

orks,

.Ad-ho

c Networks,

.7(2),.

388–400,.Ma

rch

.2009.

[IR1]

. OPNE

Mode

ler

. versio

. 10.5,. OPNE

. Tec

hnologies,

. Inc.,. avai

lable

. at. htt

p://www.opnet.com,

accessed.on.December.13,.2009.

7-12 Industrial Communication Systems

[KHP08].D..Koutsonikolas1,.Y..C..Hu,.and.K..Papagiannaki,.How.to.evaluate.exotic.wireless.routing.protocols?.

in.Pro

ceedings ACM HotNets,

.Cal

gary,

.Can

ada,

.Oct

ober

.200

[KK00]

.B..Kar

.and.H..T..Kung

.GPSR:.Gre

edy

.perim

eter

.sta

teless

.rou

ting

.for.wire

less

.netw

orks,

.in.

Pro

ceedings of the 6th Annual international Conference on Mobile Computing and Networking,

Bost

on,

.MA,.Augu

.2000.

[KK98]

.R..Krav

ets

.and.P..Kri

shnan,

.Pow

.man

agement

.tec

hniques

.for.mob

ile

.communic

ation,

.in.ACM

ternational Conference on Mobile Computing and Networking (MobiCom),

.New.Yor

.pp..157–168,.

Oct

ober

.1998.

[KKFT02]

.S..Kop

party,

.S..Kri

shnamurthy,

.M..Falo

utsos,

.and.S..K..Tri

pathi,

.Spli

.TCP.for.mob

ile

.ad-hoc.

net

works,

.IEE

E Global Telecommunications Conference GLOBECOM ‘02,

.vol

.1,.Tai

pei,

.Tai

wan,

pp..138–142,.No

vember

.2002.

[KLSSK02]

.V..Kan

odia,

.C..Li,.A..Sabh

arwal,

.B..Sadeghi,.and.E..Knigh

tly,

.Dist

ributed

.prio

rity

.sch

eduling

and.me

dium

.access.in.ad-ho

.net

works,

.ACM J

ournal of Wireless Networks,

.8,.455–466,.2002.

MS05]

.I..Kar

thigeyan,

.B..S..Man

oj,

.and.C..Siv

.Ram.Mur

thy,

.A.dis

tributed

.lax

ity-based

.pri

ority

.sch

eduling

sch

eme

.for.tim

e-sensitive

.tra

c

.in.mob

ile

.ad-

hoc

.net

works,

.Jou

rnal of Ad-hoc Networks,

.3,.27–

50,

.200

[KRD06]

.S..Kuma

.V..S..Rag

havan,

.and.J..Deng

.Medi

.access.cont

rol

.pro

tocols

.for.ad-hoc.wire

less

netw

orks:

.A.sur

vey,

.Ad H

oc Networks,

.4(3),.326–358,.Ma

.2006.

[LS01]

.J..Liu.and.S..Sing

.ATCP

.TCP.for.mob

ile

.ad-hoc.netw

orks,

.IEEE Jo

urnal on Selected Areas in

Communications,

.19,.1300–1315,.2001.

[LS98]

.J..R..Lorch.and.A..J..Smith,.Soware.strategies.for.portable.computer.energy.management,.IEEE

Jou

rnal of Personal Communications,

.5,.60–73,.1998.

[MB00]

.B..A..Mi

ller

.an

.C..Bi

sdikian,

.Bl

uetooth Revealed,

.Pr

entice

.Ha

ll,

.Ne

.Yo

rk,

.2000.

K04]

.P..Moh

apatra

.and.S..Kri

shnamurthy,

.Ad-

hoc Networks: Technologies and Protocols,

.Spr

inger,

New.Yor

.2005.

RV09]

.J..C..Mun

darath,

.P..Ram

anathan,

.and.B..D..Van.Vee

.A.qua

lity

.of.ser

vice

.awa

.cro

ss-layer

.app

roach

for.wir

eless

.ad-

hoc

.net

works

.wit

.sma

.ant

ennas,

.Ad

Hoc Networks,

.7(5

.891

–903,

.Jul

.200

[MSGJ96]

.S..Murt

.and.J..J..Gar

cia-Luna-Aceves,

.An.ec

ient

.rou

ting

.pro

tocol

.for.wir

eless

.net

works,

Jou

rnal of Mobile Networks and Applications,

.1,.183

–197,

.199

.htt

p://dx.doi.org/10.1007/BF01193336

[MWH01]

.M..Mau

ve,

.J..Widmer

.and.H..Har

tenstein,

.A.surv

.on.posit

ion-based

.rou

ting

.in.mob

ile

.ad-

hoc

.net

works,

.IEEE Ne

twork Magazine,

.15,.30–39,.2001.

[N70]

.N..Abra

mson,

. e.ALOH

.system:.Ano

ther

.alt

ernative

.for.comp

uter

.communic

ations,

.AFIPS Jo

int

Computer Conferences,

.Vo

.37,.Ho

uston,

.TX,.pp

.281–285,.No

vember

.17–19,.1970.

SL05]

.L..B..Oli

veira,

.I..G..Siq

ueira,

.and.A..A..F..Lou

reiro,

.On.the.perf

ormance

.of.ad-

hoc

.rou

ting

.pro

tocols

und

.a.pee

r-to-peer

.app

lication,

.Jou

rnal of Parallel and Distributed Computing,

.65,.133

7–1347,

.200

[PC97]

.V..Par

.and.S..Cor

son,

.Temp

orally-ordered

.rou

ting

.algo

rithm

.(TOR

A),

.vers

ion 1 functional speci-

cation, ETF Internet dra, IETF MANET Working Group,

.Flar

ion

.Tec

hnologies,

.Inc..Bridg

ewater,

NJ,.1997.

[PD

H07]

.H..Pucha,.S..M..Das,.and.Y..C..Hu,. e.perf

ormance

.impac

.of.trac.pat

terns

.on.rou

ting

.pro-

ocols

.in.mob

ile

.ad-hoc.netw

orks,

.Com

puter Networks: e International Journal of Computer and

Telecommunications Networking,

.51,.3595–3616,.2007.

[PP94]

.C..E..Perk

ins

.and.P..Bha

gwat,

.High

.dyn

amic

.destin

ation

.seq

uenced

.dist

ance

.vec

tor

.rou

ting

(DSDV

)

.fo

.mo

bile

.com

puters,

.Co

mputer Communication Review,

.234–244,.Oc

tober

.1994.

[PR99]

.C..Perk

ins

.and.E..Roy

er,

.Ad-ho

.on.deman

.dist

ance

.vec

tor

.rou

ting,

.in.Pro

ceedings of the 2nd

IEEE Workshop on Mobile Computing Systems & Applications,

.Ne

.Orle

ans,

.LA,.Fe

bruary

.1999.

[PSS00]

.P..Palen

sky,

.T..Saut

er,

.and.C..Sch

waiger,

.Sec

urity

.und.Feld

busse—ein

.Widers

pruch,

.Jou

rnal of

Information Technology,

.42,.31–37,.2000.

[PSW04]

.A..Perr

ig,

.J..Sta

nkovic,

.and.D..Wag

ner,

.Sec

urity

.in.wire

less

.sens

.netw

orks,

.Com

munications of

the ACM,

.47,.53–57,.2004.

[R96]

.M..K..Reit

er,

.Dist

ributing

.tru

.wit

.the.Ram

part

.too

lkit,

.Com

munications of the ACM,

.39(4),.

71–74,.1996.