Interference

Evaluation

of

Bluetooth

and

IEEE

b

Systems

Abstract

The

emergence

of

several

radio

technologies

such

as

Bluetooth

and

IEEE

operating

in

the

GHz

unlicensed

ISM

frequency

band

may

lead

to

signal

interference

and

result

in

significant

performance

degradation

when

devices

are

colocated

in

the

same

environment

The

main

goal

of

this

paper

is

to

evaluate

the

effect

of

mutual

interference

on

the

performance

of

Bluetooth

and

IEEE

b

systems

We

develop

a

simulation

framework

for

modeling

interference

based

on

detailed

MAC

and

PHY

models

First

we

use

a

simple

simulation

scenario

to

highlight

the

effects

of

parameters

such

as

transmission

power

offered

load

and

traffic

type

We

then

turn

to

more

complex

scenarios

involving

multiple

Bluetooth

piconets

and

WLAN

devices

The

proliferation

of

mobile

computing

devices

including

laptops

personal

digital

assistants

-LRB-

PDAs

-RRB-

and

wearable

computers

has

created

a

demand

for

wireless

personal

area

networks

-LRB-

WPANs

-RRB-

WPANs

allow

closely

located

devices

to

share

information

and

resources

A

key

challenge

in

the

design

of

WPANs

is

adapting

to

a

hostile

radio

environment

that

includes

noise

time-varying

channels

and

abundant

electromagnetic

interference

Today

most

radio

technologies

considered

by

WPANs

-LRB-

Bluetooth

Special

Interest

Group

-LSB-

-RSB-

and

IEEE

-RRB-

employ

the

GHz

ISM

frequency

band

which

is

also

used

by

Local

Area

Network

-LRB-

WLAN

-RRB-

devices

implementing

the

IEEE

b

standard

specifications

-LSB-

-RSB-

It

is

anticipated

that

some

interference

will

result

from

all

these

technologies

operating

in

the

same

environment

WLAN

devices

operating

in

proximity

to

WPAN

devices

may

significantly

impact

the

performance

of

WPAN

and

vice

versa

The

main

goal

of

this

paper

is

to

present

our

findings

on

the

performance

of

these

systems

when

operating

in

close

proximity

to

each

other

Our

results

are

based

on

detailed

models

for

the

MAC

PHY

and

wireless

channel

Recently

a

number

of

research

activities

has

led

to

the

development

of

tools

for

wireless

network

simulation

-LSB-

-RSB-

While

some

of

these

tools

include

a

PHY

layer

implementation

it

is

often

abstracted

to

a

discrete

channel

model

that

does

not

implement

interference

per

se

Therefore

in

order

to

model

interference

and

capture

the

time

and

frequency

collisions

we

chose

to

implement

an

integrated

MAC-PHY

module

Efforts

to

study

interference

in

the

GHz

band

are

relatively

recent

For

example

interference

caused

by

microwave

ovens

operating

in

the

vicinity

of

a

WLAN

network

has

been

investigated

-LSB-

-RSB-

and

requirements

on

the

signal-to-noise

ratio

-LRB-

SNR

-RRB-

are

presented

by

Kamerman

and

Erkocevic

-LSB-

-RSB-

Corresponding

author

E-mail

nada.golmie@nist.gov

In

addition

there

has

been

several

attempts

at

quantifying

the

impact

of

interference

on

both

the

WLAN

and

Bluetooth

performance

Published

results

can

be

classified

into

at

least

three

categories

depending

on

whether

they

rely

on

analysis

simulation

or

experimental

measurements

Analytical

results

based

on

probability

of

packet

collision

were

obtained

by

Shellhammer

-LSB-

-RSB-

Ennis

-LSB-

-RSB-

and

Zyren

-LSB-

-RSB-

for

the

WLAN

packet

error

and

by

Golmie

-LSB-

-RSB-

for

the

Bluetooth

packet

error

In

all

these

cases

the

probability

of

packet

error

is

computed

based

on

the

probability

of

packet

collision

in

time

and

frequency

Although

these

analytical

results

can

often

give

a

first

order

approximation

on

the

impact

of

interference

and

the

resulting

performance

degradation

they

often

make

assumptions

concerning

the

traffic

distributions

and

the

operation

of

the

media

access

protocol

which

can

make

them

less

realistic

More

importantly

in

order

for

the

analysis

to

be

tractable

mutual

interference

that

can

change

the

traffic

distribution

for

each

system

is

often

ig-nored

On

the

other

hand

experimental

results

such

as

the

ones

obtained

by

Kamerman

-LSB-

-RSB-

Howitt

et

al.

-LSB-

-RSB-

and

Fumolari

-LSB-

-RSB-

for

a

two-node

WLAN

system

and

a

two-node

Bluetooth

piconet

can

be

considered

more

accurate

at

the

cost

of

being

too

specific

to

the

implementation

tested

Thus

a

third

alternative

consists

of

using

modeling

and

simulation

to

evaluate

the

impact

of

interference

This

third

approach

can

provide

a

more

flexible

framework

Zurbes

et

al.

-LSB-

-RSB-

present

simulation

results

for

a

number

of

Bluetooth

devices

located

in

a

single

large

room

They

show

that

for

concurrent

web

sessions

performance

is

degraded

by

only

Golmie

et

al.

-LSB-

-RSB-

use

a

detailed

MAC

and

PHY

simulation

framework

to

evaluate

the

impact

of

interference

for

a

pair

of

WLAN

devices

and

a

pair

of

Bluetooth

devices

Similar

results

have

been

obtained

by

Lansford

et

al.

-LSB-

-RSB-

for

the

case

of

colocated

WLAN

and

Bluetooth

devices

on

the

same

laptop

Their

simulation

models

are

based

on

a

link

budget

analysis

and

a

theoretical

calculation

of

the

BER

-LRB-

Q

function

calculation

-RRB-

The

work

in

this

paper

is

an

extension

of

-LSB-

-RSB-

GOLMIE

ET

AL.

Figure

Master

TX/RX

hopping

sequence

This

paper

is

organized

as

follows

In

section

we

give

some

general

insights

on

the

Bluetooth

and

IEEE

protocol

operation

In

section

we

describe

in

great

detail

our

modeling

approach

for

the

MAC

PHY

and

wireless

channel

In

section

we

evaluate

the

impact

of

interference

on

both

Bluetooth

and

WLAN

performance

and

present

simulation

results

Concluding

remarks

are

offered

in

section

In

this

section

we

give

a

brief

overview

of

the

Bluetooth

technology

-LSB-

-RSB-

and

discuss

the

main

functionality

of

its

protocol

specifications

Bluetooth

is

a

short

range

-LRB-

m

-RRB-

wireless

link

technology

aimed

at

replacing

non-interoperable

proprietary

cables

that

connect

phones

laptops

PDAs

and

other

portable

devices

together

Bluetooth

operates

in

the

ISM

frequency

band

starting

at

GHz

and

ending

at

GHz

in

the

USA

and

Europe

RF

channels

of

MHz

width

are

defined

The

air

interface

is

based

on

an

antenna

power

of

mW

with

an

antenna

gain

of

dB

The

signal

is

modulated

using

binary

Gaussian

Frequency

Shift

Keying

-LRB-

GFSK

-RRB-

The

raw

data

rate

is

defined

at

Mbit/s

A

Time

Division

Multiplexing

-LRB-

TDM

-RRB-

technique

divides

the

channel

into

s

slots

Transmission

occurs

in

packets

that

occupy

an

odd

number

of

slots

-LRB-

up

to

-RRB-

Each

packet

is

transmitted

on

a

different

hop

frequency

with

a

maximum

frequency

hopping

rate

of

hops/s

Two

or

more

units

communicating

on

the

same

channel

form

a

piconet

where

one

unit

operates

as

a

master

and

the

others

-LRB-

a

maximum

of

seven

active

at

the

same

time

-RRB-

act

as

slaves

A

channel

is

defined

as

a

unique

pseudo-random

frequency

hopping

sequence

derived

from

the

master

device

's

address

and

its

Bluetooth

clock

value

Slaves

in

the

piconet

synchronize

their

timing

and

frequency

hopping

to

the

master

upon

connection

establishment

In

the

connection

mode

the

master

controls

the

access

to

the

channel

using

a

polling

scheme

where

master

and

slave

transmissions

alternate

A

slave

packet

always

follows

a

master

packet

transmission

as

illustrated

in

figure

which

depicts

the

master

's

view

of

the

slotted

TX/RX

channel

There

are

two

types

of

link

connections

that

can

be

established

between

a

master

and

a

slave

the

Synchronous

Connection-Oriented

-LRB-

SCO

-RRB-

and

the

Asynchronous

Connection-Less

-LRB-

ACL

-RRB-

link

The

SCO

link

is

a

symmetric

point-to-point

connection

between

a

master

and

a

slave

where

the

master

sends

an

SCO

packet

in

one

TX

slot

at

regular

time

intervals

defined

by

T

SCO

time

slots

The

slave

responds

with

an

SCO

packet

in

the

next

TX

opportunity

T

SCO

is

set

to

either

or

time

slots

for

or

packet

formats

respectively

All

three

formats

of

SCO

packets

are

defined

to

carry

Kbit/s

of

voice

traffic

and

are

never

retransmitted

in

case

of

packet

loss

or

error

The

ACL

link

is

an

asymmetric

point-to-point

connection

between

a

master

and

active

slaves

in

the

piconet

An

Automatic

Repeat

Request

-LRB-

ARQ

-RRB-

procedure

is

applied

to

ACL

packets

where

packets

are

retransmitted

in

case

of

loss

until

a

positive

acknowledgement

-LRB-

ACK

-RRB-

is

received

at

the

source

The

ACK

is

piggy-backed

in

the

header

of

the

returned

packet

where

an

ARQN

bit

is

set

to

either

or

depending

on

whether

or

not

the

previous

packet

was

successfully

received

In

addition

a

sequence

number

-LRB-

SEQN

-RRB-

bit

is

used

in

the

packet

header

in

order

to

provide

a

sequential

ordering

of

data

packets

in

a

stream

and

filter

out

retransmissions

at

the

destination

Forward

Error

Correction

-LRB-

FEC

-RRB-

is

used

on

some

SCO

and

ACL

packets

in

order

to

correct

errors

and

reduce

the

number

of

ACL

retransmissions

Both

ACL

and

SCO

packets

have

the

same

packet

format

It

consists

of

a

access

code

used

for

message

identification

and

synchronization

a

header

and

a

variable

length

payload

that

contains

either

a

voice

or

a

data

packet

depending

on

the

type

of

link

connection

that

is

established

between

a

master

and

a

slave

A

repetition

code

of

rate

is

applied

to

the

header

and

a

block

code

with

minimum

distance

d

min

equal

to

is

applied

to

the

access

code

so

that

up

to

errors

are

detected

and

-LRB-

d

min

-RRB-

can

be

corrected

Note

that

uncorrected

errors

in

the

header

and

the

access

code

lead

to

a

packet

drop

Voice

packets

have

a

total

packet

length

of

bits

including

the

access

code

and

header

A

repetition

code

of

is

used

for

packet

payload

On

the

other

hand

DM

and

packet

payloads

use

a

block

code

where

every

bits

of

information

are

encoded

with

bits

DH

and

packets

do

not

have

any

encoding

on

their

payload

HV

packets

do

INTERFERENCE

EVALUATION

OF

BLUETOOTH

AND

IEEE

b

SYSTEMS

Figure

WLAN

frame

transmission

scheme

Table

Summary

of

error

occurrences

in

the

packet

and

actions

taken

in

case

errors

are

not

corrected

Error

location

Error

correction

Action

taken

Access

code

d

min

Packet

dropped

Packet

header

repetition

Packet

dropped

payload

repetition

Packet

accepted

payload

block

code

Packet

accepted

payload

No

FEC

Packet

accepted

payload

block

code

Packet

dropped

payload

No

FEC

Packet

accepted

not

have

a

CRC

in

the

payload

In

case

of

an

error

occurrence

in

the

payload

the

packet

is

never

dropped

Uncorrected

errors

for

DM

and

DH

packets

lead

to

dropped

packets

and

the

application

of

the

ARQ

and

SEQN

schemes

Table

summarizes

the

error

occurrences

in

the

packet

and

the

actions

taken

by

the

protocol

IEEE

b

The

IEEE

standard

-LSB-

-RSB-

defines

both

the

physical

-LRB-

PHY

-RRB-

and

medium

access

control

-LRB-

MAC

-RRB-

layer

protocols

for

WLANs

In

this

sequel

we

shall

be

using

WLAN

and

b

interchangeably

The

IEEE

standard

calls

for

three

different

PHY

specifications

frequency

hopping

-LRB-

FH

-RRB-

spread

spectrum

direct

sequence

-LRB-

DS

-RRB-

spread

spectrum

and

infrared

-LRB-

IR

-RRB-

The

transmit

power

for

DS

and

FH

devices

is

defined

at

a

maximum

of

W

and

the

receiver

sensitivity

is

set

to

dBmW

Antenna

gain

is

limited

to

dB

maximum

In

this

work

we

focus

on

the

b

specification

-LRB-

DS

spread

spectrum

-RRB-

since

it

is

in

the

same

frequency

band

as

Bluetooth

and

the

most

commonly

deployed

The

basic

data

rate

for

the

DS

system

is

Mbit/s

encoded

with

differential

binary

phase

shift

keying

-LRB-

DBPSK

-RRB-

Similarly

a

Mbit/s

rate

is

provided

using

differential

quadrature

phase

shift

keying

-LRB-

DQPSK

-RRB-

at

the

same

chip

rate

of

chips/s

Higher

rates

of

and

Mbit/s

are

also

available

using

techniques

combining

quadrature

phase

shift

keying

and

complementary

code

keying

-LRB-

CCK

-RRB-

all

of

these

systems

use

MHz

channels

The

IEEE

MAC

layer

specifications

common

to

all

PHYs

and

data

rates

coordinate

the

communication

between

stations

and

control

the

behavior

of

users

who

want

to

access

the

network

The

Distributed

Coordination

Function

-LRB-

DCF

-RRB-

which

describes

the

default

MAC

protocol

operation

is

based

on

a

scheme

known

as

carrier-sense

multiple

access

collision

avoidance

-LRB-

CSMA/CA

-RRB-

Both

the

MAC

and

PHY

layers

cooperate

in

order

to

implement

collision

avoidance

procedures

The

PHY

layer

samples

the

received

energy

over

the

medium

transmitting

data

and

uses

a

clear

channel

assessment

-LRB-

CCA

-RRB-

algorithm

to

determine

if

the

channel

is

clear

This

is

accomplished

by

measuring

the

RF

energy

at

the

antenna

and

determining

the

strength

of

the

received

signal

commonly

known

as

RSSI

or

received

signal

strength

indicator

In

addition

carrier

sense

can

be

used

to

determine

if

the

channel

is

available

This

technique

is

more

selective

since

it

verifies

that

the

signal

is

the

same

carrier

type

as

transmitters

In

all

of

our

simulations

we

use

carrier

sense

and

not

RSSI

to

determine

if

the

channel

is

busy

Thus

a

Bluetooth

signal

will

corrupt

WLAN

packets

but

it

will

not

cause

the

WLAN

to

defer

transmission

A

virtual

carrier

sense

mechanism

is

also

provided

at

the

MAC

layer

It

uses

the

request-to-send

-LRB-

RTS

-RRB-

and

clear-to-send

-LRB-

CTS

-RRB-

message

exchange

to

make

predictions

of

future

traffic

on

the

medium

and

updates

the

network

allocation

vector

-LRB-

NAV

-RRB-

available

in

stations

Communication

is

established

when

one

of

the

wireless

nodes

sends

a

short

RTS

frame

The

receiving

station

issues

a

CTS

frame

that

echoes

the

sender

's

address

If

the

CTS

frame

is

not

received

it

is

assumed

that

a

collision

occurred

and

the

RTS

process

starts

over

Regardless

of

whether

the

virtual

carrier

sense

routine

is

used

or

not

the

MAC

is

required

to

implement

a

basic

access

procedure

-LRB-

depicted

in

figure

-RRB-

as

follows

If

a

station

has

data

to

send

it

waits

for

the

channel

to

be

idle

through

the

use

of

the

CSMA/CA

algorithm

If

the

medium

is

sensed

idle

for

a

period

greater

than

a

DCF

interframe

space

-LRB-

DIFS

-RRB-

the

station

goes

into

a

backoff

procedure

before

it

sends

its

frame

Upon

the

successful

reception

of

a

frame

the

destination

station

returns

an

ACK

frame

after

a

Short

interframe

space

-LRB-

SIFS

-RRB-

The

backoff

window

is

based

on

a

random

value

uniformly

distributed

in

the

interval

-LSB-

CW

min

CW

max

-RSB-

where

CW

min

and

CW

max

represent

the

Contention

Window

parameters

If

the

medium

is

determined

busy

at

any

time

during

the

backoff

slot

the

backoff

procedure

is

suspended

It

is

resumed

after

the

medium

has

been

idle

for

the

duration

of

the

DIFS

period

If

an

ACK

is

not

received

within

an

ACK

timeout

interval

the

station

assumes

that

either

the

data

frame

or

the

ACK

was

lost

GOLMIE

ET

AL.

and

needs

to

retransmit

its

data

frame

by

repeating

the

basic

access

procedure

Errors

are

detected

by

checking

the

Frame

Check

Sequence

-LRB-

FCS

-RRB-

that

is

appended

to

the

packet

payload

In

case

an

error

is

found

the

packet

is

dropped

and

is

then

later

retransmitted

In

this

section

we

describe

the

methodology

and

platform

used

to

conduct

the

performance

evaluation

The

simulation

environment

consists

of

detailed

models

for

the

RF

channel

the

PHY

and

MAC

layers

developed

in

C

and

OPNET

-LRB-

for

the

MAC

layer

-RRB-

These

detailed

simulation

models

constitute

an

evaluation

framework

that

is

critical

to

studying

the

various

intricate

effects

between

the

MAC

and

PHY

layers

Although

interference

is

typically

associated

with

the

RF

channel

modeling

and

measured

at

the

PHY

layer

it

can

significantly

impact

the

performance

of

higher

layer

applications

including

the

MAC

layer

Similarly

changes

in

the

behavior

of

the

MAC

layer

protocol

and

the

associated

data

traffic

distribution

can

play

an

important

factor

in

the

interference

scenario

and

affect

the

overall

system

performance

Figure

shows

a

packet

being

potentially

corrupted

by

two

interference

packets

Consider

that

the

desired

packet

is

from

the

WLAN

and

the

interference

packets

are

Bluetooth

-LRB-

the

figure

is

equally

valid

if

the

roles

are

reversed

except

that

the

frequencies

of

the

packets

will

be

different

-RRB-

For

interference

to

occur

the

packets

must

overlap

in

both

time

and

frequency

That

is

the

interference

packets

must

be

within

the

MHz

bandwidth

of

the

WLAN

In

a

system

with

many

Bluetooth

piconets

there

may

be

interference

from

more

than

one

packet

at

any

given

time

We

define

a

period

of

stationarity

-LRB-

POS

-RRB-

as

the

time

during

which

the

interference

is

constant

For

example

t

i

t

t

i

is

such

a

period

as

is

t

i

t

t

i

Even

during

a

POS

where

there

is

one

or

more

interferers

the

number

and

location

of

bit

errors

in

the

desired

packet

depends

on

a

number

of

factors

-LRB-

-RRB-

the

signal-to-interference

ratio

-LRB-

SIR

-RRB-

and

the

signal-to-noise

ratio

at

the

receiver

-LRB-

-RRB-

the

type

of

modulation

used

by

the

transmitter

and

the

interferer

and

-LRB-

-RRB-

the

channel

model

For

this

reason

it

is

essential

to

use

accurate

models

of

the

PHY

and

channel

as

described

below

Just

because

two

packets

overlap

in

time

and

frequency

does

not

necessary

lead

to

bit

errors

and

the

consequent

packet

loss

While

one

can

use

-LRB-

semi

-RRB-

analytic

models

instead

such

as

approximating

Bluetooth

interference

on

WLAN

as

a

narrowband

tone

jammer

the

use

of

detailed

signal

processing-based

models

better

allows

one

to

handle

multiple

simultaneous

interferers

In

order

to

simulate

the

overall

system

an

interface

module

was

created

that

allows

the

MAC

models

to

use

the

physical

layer

and

channel

models

This

interface

module

captures

all

changes

in

the

channel

state

-LRB-

mainly

in

the

energy

level

-RRB-

Consider

the

Bluetooth

transmitter

channel

receiver

chain

of

processes

For

a

given

packet

the

transmitter

creates

a

set

of

Figure

Packet

collision

and

placement

of

errors

The

bit

error

rate

-LRB-

BER

-RRB-

is

roughly

constant

during

each

of

the

three

indicated

periods

signal

samples

that

are

corrupted

by

the

channel

and

input

to

the

receiver

interference

may

be

present

for

all

or

only

specific

periods

of

stationarity

as

shown

in

figure

A

similar

chain

of

processing

occurs

for

an

b

packet

The

interface

module

is

designed

to

process

a

packet

at

a

time

At

the

end

of

each

packet

transmission

the

MAC

layer

generates

a

data

structure

that

contains

all

the

information

required

to

process

the

packet

This

structure

includes

a

list

of

all

the

interfering

packets

with

their

respective

duration

timing

offset

frequency

and

transmitted

power

The

topology

of

the

scenario

is

also

included

The

data

structure

is

then

passed

to

the

physical

layer

along

with

a

stream

of

bits

representing

the

packet

being

transmitted

The

physical

layer

returns

the

bit

stream

after

placing

the

errors

resulting

from

the

interference

MAC

model

We

used

OPNET

to

develop

a

simulation

model

for

the

Bluetooth

and

IEEE

protocols

For

Bluetooth

we

implemented

the

access

protocol

according

to

the

specifications

-LSB-

-RSB-

We

assume

that

a

connection

is

already

established

between

the

master

and

the

slave

and

that

the

synchronization

process

is

complete

The

Bluetooth

hopping

pattern

algorithm

is

implemented

Details

of

the

algorithm

are

provided

in

section

A

pseudo-random

number

generator

is

used

instead

of

the

implementation

specific

circuitry

that

uses

the

master

's

clock

and

address

to

derive

a

random

number

For

the

IEEE

protocol

we

used

the

model

available

in

the

OPNET

library

and

modified

it

to

bypass

the

OPNET

radio

model

and

to

use

our

MAC/PHY

interface

module

We

focus

in

this

study

on

the

Direct

Sequence

mode

which

uses

a

fixed

frequency

that

occupies

MHz

of

the

frequency

band

The

center

frequency

is

set

to

GHz

At

the

MAC

layer

a

set

of

performance

metrics

are

defined

including

probability

of

packet

loss

Packet

loss

measures

the

number

of

packets

discarded

at

the

MAC

layer

due

to

errors

in

the

bit

stream

This

measure

is

calculated

after

performing

error

correction

PHY

model

The

transmitters

channel

and

receivers

are

implemented

at

complex

baseband

For

a

given

transmitter

inphase

INTERFERENCE

EVALUATION

OF

BLUETOOTH

AND

IEEE

b

SYSTEMS

and

quadrature

samples

are

generated

at

a

sampling

rate

of

per

second

This

rate

provides

four

samples/symbol

for

the

Mbit/s

mode

enough

to

implement

a

good

receiver

It

is

also

high

enough

to

allow

digital

modulation

of

the

Bluetooth

signal

to

account

for

its

frequency

hopping

Specifically

since

the

Bluetooth

signal

is

approximately

MHz

wide

it

can

be

modulated

up

to

almost

MHz

which

is

more

than

enough

to

cover

the

MHz

bandwidth

-LRB-

one-sided

-RRB-

of

the

signal

The

received

complex

samples

from

both

the

desired

transmitter

and

the

interferer

-LRB-

s

-RRB-

are

added

together

at

the

receiver

While

there

are

a

number

of

possible

Bluetooth

receiver

designs

we

chose

to

implement

the

noncoherent

limiter-discriminator

-LRB-

LD

-RRB-

receiver

-LSB-

-RSB-

Its

simplicity

and

relatively

low

cost

should

make

it

the

most

common

type

for

many

consumer

applications

Details

of

the

actual

design

are

given

in

-LSB-

-RSB-

In

the

b

CCK

receiver

each

group

of

eight

information

bits

chooses

a

sequence

of

eight

consecutive

chips

that

forms

a

symbol

As

before

the

inphase

and

quadrature

components

of

these

chips

are

transmitted

The

receiver

looks

at

the

received

symbol

and

decides

which

was

the

most

likely

transmitted

one

While

one

can

implement

this

decoding

procedure

by

correlating

against

all

possible

symbols

we

chose

a

slightly

sub-optimal

but

considerably

faster

architecture

similar

to

the

Walsh

Hadamard

transform

again

details

can

be

found

in

-LSB-

-RSB-

Channel

model

The

channel

model

consists

of

a

geometry-based

propagation

model

for

the

signals

as

well

as

a

noise

model

For

the

indoor

channel

we

apply

a

propagation

model

consisting

of

two

parts

-LRB-

-RRB-

line-of-sight

propagation

-LRB-

free-space

-RRB-

for

the

first

m

and

-LRB-

-RRB-

a

propagation

exponent

of

for

distances

over

m.

Consequently

the

path

loss

in

dB

is

given

by

L

p

log

-LRB-

f

d

-RRB-

if

d

m

log

otherwise

-LRB-

-RRB-

where

f

is

the

frequency

in

GHz

and

d

is

the

distance

in

meters

This

model

is

similar

to

the

one

used

by

Kamerman

-LSB-

-RSB-

Assuming

unit

gain

for

the

transmitter

and

receiver

antennas

and

ignoring

additional

losses

the

received

power

in

dBmW

is

P

R

P

T

L

p

-LRB-

-RRB-

where

P

T

is

the

transmitted

power

also

in

dBmW

Equation

-LRB-

-RRB-

is

used

for

calculating

the

power

received

at

a

given

point

due

to

either

a

Bluetooth

or

an

transmitter

since

this

equation

does

not

depend

on

the

modulation

method

The

main

parameter

that

drives

the

PHY

layer

performance

is

the

signal-to-interference

ratio

between

the

desired

signal

and

the

interfering

signal

This

ratio

is

given

in

dB

by

SIR

P

R

P

I

-LRB-

-RRB-

where

P

I

is

the

interference

power

at

the

receiver

In

the

absence

of

interference

the

bit

error

rate

for

either

the

Bluetooth

or

WLAN

system

is

almost

negligible

for

the

transmitter

powers

and

ranges

under

consideration

To

complete

the

channel

model

noise

is

added

to

the

received

samples

according

to

the

specified

SNR

In

decibels

the

signal-to-noise

ratio

is

defined

by

SNR

P

R

S

R

where

P

R

is

the

received

signal

power

and

S

R

is

the

receiver

's

sensitivity

in

dBmW

this

latter

value

is

dependent

on

the

receiver

model

and

so

is

an

input

parameter

Additive

white

Gaussian

noise

-LRB-

AWGN

-RRB-

is

used

to

model

the

noise

at

the

receivers

Model

validation

The

results

obtained

from

the

simulation

models

were

validated

against

experimental

and

analytical

results

Since

the

implementation

of

the

PHY

layer

required

choosing

a

number

of

design

parameters

the

first

step

in

the

validation

process

is

comparing

the

PHY

results

against

theoretical

results

Complete

BER

curves

of

the

Bluetooth

and

b

systems

are

given

in

-LSB-

-RSB-

for

the

AWGN

and

flat

Rician

channels

without

interference

all

the

results

match

very

closely

to

analytical

bounds

and

other

simulation

results

Also

the

simulation

results

for

both

the

MAC

and

PHY

models

were

compared

and

validated

against

analytical

results

for

packet

loss

given

different

traffic

scenarios

-LSB-

-RSB-

For

the

experimental

testing

we

use

the

topology

in

figure

and

compare

the

packet

loss

observed

for

Bluetooth

voice

and

WLAN

data

with

the

simulation

results

in

figure

The

experimental

and

simulation

results

are

in

good

agreement

We

present

simulation

results

to

evaluate

the

performance

of

Bluetooth

in

the

presence

of

WLAN

interference

and

vice

versa

First

we

consider

the

effects

of

parameters

such

as

transmitted

power

offered

load

hop

rate

and

traffic

type

on

interference

Second

we

look

at

two

realistic

interference

scenarios

to

quantify

the

severity

of

the

performance

degradation

for

the

Bluetooth

and

WLAN

systems

Factors

effecting

interference

We

first

consider

a

four

node

topology

consisting

of

two

WLAN

devices

and

two

Bluetooth

devices

-LRB-

one

master

and

one

slave

-RRB-

as

shown

in

figure

The

WLAN

access

point

-LRB-

AP

-RRB-

is

located

at

-LRB-

-RRB-

m

and

the

WLAN

mobile

is

fixed

at

-LRB-

-RRB-

m

The

Bluetooth

slave

device

is

fixed

at

-LRB-

-RRB-

m

and

the

master

is

fixed

at

-LRB-

-RRB-

m

In

an

effort

to

control

the

interference

on

Bluetooth

and

WLAN

we

define

two

scenarios

In

the

first

scenario

we

let

the

mobile

be

the

generator

of

data

while

the

AP

is

the

sink

In

this

case

the

interference

is

from

the

mobile

sending

data

packets

to

the

AP

and

receiving

acknowledgments

-LRB-

ACKs

-RRB-

from

it

Since

most

of

the

WLAN

traffic

is

GOLMIE

ET

AL.

Figure

Topology

Two

WLAN

devices

and

one

Bluetooth

piconet

Table

Summary

of

the

scenarios

Scenario

Desired

Interferer

WLAN

WLAN

signal

signal

AP

mobile

Bluetooth

WLAN

Sink

Source

WLAN

Bluetooth

Source

Sink

originating

close

to

the

Bluetooth

piconet

both

the

master

and

the

slave

may

suffer

from

serious

interference

In

the

second

scenario

the

traffic

is

generated

at

the

AP

and

received

at

the

WLAN

mobile

Because

the

data

packets

are

generally

longer

then

the

ACKs

this

is

a

more

critical

scenario

for

the

WLAN

then

when

the

mobile

is

the

source

Table

summarizes

the

two

scenarios

For

Bluetooth

we

consider

two

types

of

applications

voice

and

data

For

voice

we

assume

a

symmetric

stream

of

Kbit/s

each

way

using

packet

encapsulation

For

data

traffic

we

consider

a

source

that

generates

packets

The

packet

interarrival

time

is

exponentially

distributed

and

its

mean

in

seconds

is

computed

according

to

t

B

n

s

T

s

-LRB-

-RRB-

where

is

the

offered

load

n

s

is

the

number

of

slots

occupied

by

a

packet

For

n

s

T

s

is

the

slot

size

equal

to

s.

For

WLAN

we

use

the

Mbit/s

mode

and

consider

a

data

application

Typical

applications

for

WLAN

could

be

ftp

or

http

However

since

we

are

mainly

interested

in

the

MAC

layer

performance

we

abstract

the

parameters

for

the

application

model

to

packet

size

and

offered

load

and

do

not

model

the

entire

TCP/IP

stack

We

fix

the

packet

payload

to

bits

which

is

the

maximum

size

for

the

MAC

payload

data

unit

and

vary

The

packet

interarrival

time

in

seconds

t

W

is

exponentially

distributed

and

its

mean

is

computed

acTable

Simulation

parameters

Simulation

parameters

Values

Propagation

delay

s/km

Length

of

simulation

run

s

Bluetooth

parameters

ACL

Baseband

Packet

Encapsulation

SCO

Baseband

Packet

Encapsulation

Transmitted

Power

mW

WLAN

parameters

Transmitted

power

mW

Packet

header

bits

Packet

payload

bits

cording

to

t

W

-LRB-

-RRB-

where

the

PLCP

header

is

sent

at

Mbit/s

and

the

payload

at

Mbit/s

Unless

specified

otherwise

we

use

the

configuration

and

system

parameters

shown

in

table

For

scenarios

and

we

run

trials

using

a

different

random

seed

for

each

trial

In

addition

to

plotting

the

mean

value

confidence

intervals

showing

plus

and

minus

two

standard

deviations

are

also

included

From

figures

and

one

sees

that

the

statistical

variation

around

the

mean

values

are

very

small

In

addition

to

the

comparisons

with

analytical

and

experimental

results

described

in

section

this

fact

provides

further

validation

for

the

results

WLAN

transmission

power

First

we

look

at

the

effect

on

Bluetooth

of

increasing

the

WLAN

transmission

power

in

scenario

that

is

increasing

the

interferer

transmission

power

on

the

victim

signal

Since

power

control

algorithms

exist

in

many

WLAN

implementa-tions

it

is

important

to

consider

how

varying

the

transmitted

power

changes

the

interference

However

since

Bluetooth

was

designed

as

a

low

power

device

we

fix

its

transmitter

power

at

mW

for

all

simulations

We

fix

WLAN

to

for

different

Bluetooth

traffic

types

and

values

of

In

figure

-LRB-

a

-RRB-

we

note

a

saturation

effect

around

mW

A

threshold

which

is

close

to

corresponds

to

the

probability

that

Bluetooth

is

hopping

in

the

WLAN

occupied

band

Thus

increasing

the

WLAN

transmission

power

beyond

mW

does

not

affect

the

Bluetooth

packet

loss

Between

and

mW

a

small

change

in

the

WLAN

transmitted

power

triples

the

Bluetooth

packet

loss

Please

note

the

relative

positions

of

the

packet

loss

curves

for

different

values

of

between

and

mW

as

increases

the

packet

loss

is

higher

Also

note

that

Bluetooth

voice

has

the

lowest

packet

loss

partly

due

to

its

short

packet

size

A

second

reason

for

the

low

loss

probability

is

that

voice

packets

are

rejected

only

if

there

are

errors

in

the

access

code

or

packet

headers

cf.

table

A

packet

may

be

accepted

with

a

relatively

large

number

of

bit

errors

in

the

payload

which

may

lead

to

a

substantial

reduction

in

subjective

voice

quality

Figure

-LRB-

b

-RRB-

shows

the

probability

of

packet

loss

for

the

WLAN

mobile

device

This

corresponds

to

ACKs

being

INTERFERENCE

EVALUATION

OF

BLUETOOTH

AND

IEEE

b

SYSTEMS

-LRB-

a

-RRB-

-LRB-

b

-RRB-

-LRB-

c

-RRB-

Figure

WLAN

-LRB-

a

-RRB-

Scenario

Probability

of

packet

loss

for

the

Bluetooth

slave

-LRB-

b

-RRB-

Scenario

Probability

of

packet

loss

for

the

WLAN

mobile

-LRB-

c

-RRB-

Scenario

Probability

of

packet

loss

for

the

WLAN

mobile

dropped

at

the

WLAN

source

The

general

trend

is

that

the

packet

loss

decreases

as

the

WLAN

transmitted

power

increases

However

we

notice

a

slight

bump

between

and

mW

This

is

due

to

the

effect

of

closed-loop

interference

The

WLAN

source

increases

its

transmitted

power

and

causes

more

interference

on

the

Bluetooth

devices

as

a

result

there

are

more

retransmissions

in

both

the

Bluetooth

and

WLAN

piconets

which

causes

more

lost

ACKs

at

the

WLAN

source

Next

we

consider

the

effect

of

increasing

the

WLAN

transmission

power

on

the

WLAN

performance

in

scenario

From

figure

-LRB-

c

-RRB-

we

observe

that

even

if

the

WLAN

transmission

power

is

fifty

times

more

than

the

Bluetooth

transmission

power

-LRB-

fixed

at

mW

-RRB-

the

packet

loss

for

the

WLAN

does

not

change

This

leads

us

to

an

interesting

observation

on

power

control

Basically

we

note

that

increasing

the

transmission

power

does

not

necessarily

improve

the

performance

However

decreasing

the

transmission

power

is

usu-ally

a

good

neighbor

strategy

that

may

help

reduce

the

interference

on

other

devices

Offered

load

The

offered

load

also

referred

to

in

some

cases

as

duty

cycle

is

an

interesting

parameter

to

track

Consider

scenario

where

Bluetooth

is

the

interferer

and

fix

the

WLAN

transmission

power

to

mW

We

observe

that

for

the

WLAN

the

packet

loss

is

proportional

to

the

Bluetooth

offered

load

as

shown

in

figure

For

equal

and

the

packet

loss

is

and

respectively

This

observation

has

been

confirmed

analytically

in

-LSB-

-RSB-

where

the

packet

error

is

shown

to

depend

not

only

on

the

offered

load

of

the

interferer

system

but

also

on

the

packet

sizes

of

both

systems

Also

note

that

the

probability

of

loss

for

the

WLAN

GOLMIE

ET

AL.

Figure

Scenario

Probability

of

packet

loss

for

the

WLAN

mobile

fered

load

is

slightly

higher

than

for

the

WLAN

offered

load

However

this

difference

is

statistically

insignificant

The

significance

of

the

packet

size

is

apparent

in

figures

-LRB-

a

-RRB-

and

-LRB-

c

-RRB-

where

short

Bluetooth

voice

packets

lead

to

less

packet

loss

for

Bluetooth

but

cause

more

interference

for

WLAN

However

for

the

WLAN

Mbit/s

rate

the

effect

of

changing

the

WLAN

packet

size

over

the

range

to

bits

has

very

little

effect

on

the

performance

of

both

the

WLAN

and

Bluetooth

and

that

is

due

to

the

relatively

short

transmission

time

of

the

WLAN

packet

At

the

Mbit/s

rate

WLAN

packets

of

the

same

bit

lengths

take

considerably

longer

to

transmit

and

the

effect

of

packet

size

is

somewhat

more

pronounced

For

a

further

discussion

of

the

Mbit/s

case

please

see

-LSB-

-RSB-

Bluetooth

hop

rate

In

order

to

highlight

the

effect

of

the

Bluetooth

hop

rate

on

WLAN

we

use

different

packet

types

and

these

packets

occupy

and

time

slots

respectively

The

Bluetooth

hop

rate

is

determined

by

the

number

of

time

slots

occupied

by

a

packet

Thus

the

hop

rate

is

and

hops/s

for

and

packets

respectively

The

offered

load

for

Bluetooth

is

set

to

The

results

in

table

clearly

indicate

that

a

faster

hop

rate

leads

to

higher

packet

losses

-LRB-

and

for

and

respectively

-RRB-

Note

that

the

results

are

rather

insensitive

to

the

WLAN

offered

load

Bluetooth

traffic

type

The

question

here

is

whether

Bluetooth

voice

effects

WLAN

more

than

Bluetooth

data

and

vice

versa

We

use

three

types

of

packets

for

voice

encapsulation

namely

and

represents

the

worst

case

of

interference

for

WLAN

as

shown

in

table

with

packet

loss

and

which

contain

less

error

correction

and

more

user

information

are

sent

less

often

and

therefore

interfer

less

with

WLAN

-LRB-

and

for

and

respectively

-RRB-

The

Table

Scenario

Probability

of

WLAN

packet

loss

versus

Bluetooth

hop

rate

BT

WLAN

WLAN

Table

Scenario

Probability

of

WLAN

packet

loss

versus

Bluetooth

traffic

type

BT

WLAN

WLAN

Voice

Data

Table

Scenario

Probability

of

Bluetooth

packet

loss

versus

Bluetooth

traffic

type

BT

WLAN

WLAN

Voice

Data

WLAN

packet

loss

with

Bluetooth

data

interference

is

Please

note

that

the

results

do

not

depend

on

the

WLAN

offered

load

On

the

other

hand

the

probability

of

packet

loss

for

Bluetooth

data

-LRB-

-RRB-

is

higher

than

for

Bluetooth

voice

-LRB-

-RRB-

as

shown

in

table

Note

that

doubling

the

WLAN

offered

load

to

doubles

the

Bluetooth

voice

packet

loss

Also

since

all

three

types

of

voice

packets

suffer

the

same

packet

loss

it

is

preferable

to

use

which

causes

less

interference

on

the

WLAN

The

error

correction

coding

in

and

packets

may

provide

greater

range

in

a

noise-limited

environment

but

this

coding

is

far

too

weak

to

protect

the

packets

from

interference

Instead

it

is

the

frequency

hopping

ability

of

Bluetooth

that

limits

the

damage

done

by

the

WLAN

Bluetooth

transmission

power

While

most

Bluetooth

devices

will

be

operating

at

mW

the

specification

also

allows

higher

transmitter

powers

Table

shows

the

probability

of

packet

loss

for

both

Bluetooth

and

the

WLAN

for

three

values

of

the

BT

transmitter

power

and

two

types

of

Bluetooth

traffic

As

expected

higher

transmitter

powers

lead

to

more

lost

WLAN

packets

regardless

of

the

BT

traffic

type

Increasing

the

power

from

to

mW

leads

to

approximately

a

increase

in

WLAN

loss

Conversely

the

Bluetooth

packet

error

rate

decreases

It

still

not

clear

how

beneficial

this

decrease

is

for

Bluetooth

even

a

loss

probability

of

may

lead

to

unacceptable

voice

quality

Bluetooth

packet

error

correction

So

far

the

results

shown

for

the

Bluetooth

data

are

with

packets

which

use

a

block

code

on

the

packet

payload

In

order

to

show

the

effect

of

error

correction

on

the

probabil-INTERFERENCE

EVALUATION

OF

BLUETOOTH

AND

IEEE

b

SYSTEMS

Figure

Scenario

Probability

of

packet

loss

for

the

Bluetooth

slave

Table

Scenario

Probability

of

packet

loss

versus

Bluetooth

transmission

power

-LRB-

mW

-RRB-

WLAN

BT

traffic

BT

power

BT

loss

WLAN

loss

-LRB-

mW

-RRB-

probability

probability

Voice

ity

of

packet

loss

we

repeat

scenario

and

compare

the

results

given

in

figures

-LRB-

a

-RRB-

and

obtained

with

and

packets

respectively

As

expected

the

probability

of

packet

loss

for

packets

-LRB-

figure

-LRB-

a

-RRB-

-RRB-

is

slightly

less

than

for

packets

-LRB-

figure

-RRB-

for

WLAN

transmission

powers

less

than

mW

Thus

for

low

levels

of

interference

a

block

code

can

reduce

the

probability

of

loss

by

However

for

WLAN

transmission

powers

above

mW

the

probability

of

packet

loss

is

the

same

for

both

and

packets

Realistic

interference

topologies

In

this

section

we

consider

two

practical

interference

topologies

While

they

appear

to

be

somewhat

different

they

actually

complement

each

other

The

first

one

has

the

WLAN

device

in

the

midst

of

the

Bluetooth

piconets

acting

at

the

source

while

the

second

one

has

the

WLAN

access

point

acting

as

the

source

Topology

We

first

look

at

the

topology

illustrated

in

figure

It

consists

of

one

WLAN

AP

located

at

-LRB-

-RRB-

m

and

one

WLAN

mobile

at

-LRB-

-RRB-

m

The

WLAN

traffic

is

generated

at

the

mobile

while

the

AP

returns

acknowledgments

The

distance

between

the

WLAN

AP

and

mobile

is

d

W

m

There

Figure

Topology

Two

WLAN

devices

and

ten

Bluetooth

piconets

Table

Experiment

results

BT

traffic

WLAN

BT

loss

WLAN

loss

d

B

m

d

B

m

Voice

are

ten

Bluetooth

piconets

randomly

placed

covering

a

disk

The

center

of

the

disk

is

located

at

-LRB-

-RRB-

and

its

radius

is

r

m

We

define

d

B

as

the

distance

between

a

Bluetooth

master

and

slave

pair

d

B

m

for

half

of

the

master

and

slave

pairs

while

d

B

m

for

the

other

half

of

the

master

and

slave

pairs

In

this

case

the

main

interference

on

Bluetooth

is

caused

by

the

WLAN

source

located

in

the

center

of

the

disk

the

aggregation

of

the

ten

piconets

affects

the

WLAN

source

We

found

that

when

the

WLAN

system

is

not

operating

the

Bluetooth

packet

loss

is

negligible

-LRB-

less

than

-RRB-

Table

gives

the

packet

loss

for

the

Bluetooth

and

WLAN

devices

The

packet

loss

for

the

Bluetooth

devices

is

averaged

over

the

master

and

slave

devices

and

split

into

two

groups

piconets

with

d

B

m

and

piconets

with

d

B

m.

For

WLAN

the

packet

loss

is

measured

at

the

source

It

is

effectively

zero

at

the

sink

We

observe

that

the

WLAN

packet

loss

depends

on

the

Bluetooth

traffic

load

value

As

is

varied

from

to

the

WLAN

packet

loss

is

significantly

changed

from

to

However

the

WLAN

packet

loss

is

insensitive

to

the

WLAN

offered

load

Consistent

with

previous

results

Bluetooth

voice

represents

the

worst

case

interference

scenario

for

WLAN

GOLMIE

ET

AL.

In

general

the

Bluetooth

packet

loss

for

d

B

m

is

less

than

for

d

B

m

The

reason

is

that

when

the

Bluetooth

signal

is

stronger

-LRB-

over

a

shorter

distance

-RRB-

the

impact

of

interference

is

less

significant

Topology

We

next

consider

the

topology

given

in

figure

It

includes

one

WLAN

AP

and

four

WLAN

mobile

devices

The

WLAN

AP

is

located

at

-LRB-

-RRB-

m

and

it

is

the

source

of

the

traffic

generation

The

four

WLAN

mobile

devices

are

placed

on

a

two-dimensional

grid

at

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

and

-LRB-

-RRB-

m

In

this

topology

there

are

four

Bluetooth

piconets

each

consisting

of

a

master

slave

device

pair

The

placement

of

the

Bluetooth

devices

is

as

shown

in

the

figure

In

this

case

we

are

looking

at

the

effect

of

Bluetooth

piconets

on

the

four

WLAN

sink

devices

The

packet

loss

measure

for

WLAN

is

averaged

over

the

four

devices

As

shown

in

table

the

impact

of

WLAN

interference

on

Bluetooth

is

minimal

given

that

the

WLAN

source

is

far

from

the

Bluetooth

piconets

As

expected

the

WLAN

packet

loss

depends

on

the

Bluetooth

traffic

conditions

and

it

is

rather

insensitive

to

the

WLAN

traffic

activity

With

Bluetooth

voice

the

WLAN

packet

loss

is

close

to

It

is

for

Bluetooth

data

with

WLAN

loads

of

We

presented

results

on

the

performance

of

Bluetooth

and

WLAN

operating

in

the

GHz

ISM

band

based

on

detailed

channel

MAC

and

PHY

layer

models

for

both

systems

The

evaluation

framework

used

allows

us

to

study

the

impact

of

interference

in

a

closed

loop

environment

where

two

systems

are

affecting

each

other

and

explore

the

MAC

and

PHY

layer

interactions

in

each

system

We

are

able

to

draw

some

useful

conclusions

based

on

our

results

First

we

note

that

power

control

may

have

limited

benefits

in

this

environment

Increasing

the

WLAN

transmission

power

to

even

fifty

times

the

power

of

Bluetooth

is

not

sufficient

to

reduce

the

WLAN

packet

loss

On

the

other

hand

limiting

the

WLAN

power

may

help

avoid

interference

to

Bluetooth

Second

using

a

slower

hop

rate

for

Bluetooth

-LRB-

i.e.

longer

packet

sizes

-RRB-

may

cause

less

interference

to

WLAN

Third

Bluetooth

voice

represents

the

worst

type

of

interference

for

WLAN

In

addition

the

WLAN

performance

seems

to

degrade

as

the

Bluetooth

offered

load

is

increased

Finally

the

use

of

error

correcting

block

codes

in

the

Bluetooth

payload

does

not

improve

performance

The

errors

caused

by

interference

are

often

too

many

to

correct

Overall

the

results

are

dependent

on

the

traffic

distribution

Yet

there

may

be

little

room

for

parameter

optimization

especially

for

the

practical

scenarios

Not

only

does

the

complexity

of

the

interactions

and

the

number

of

parameters

to

adjust

make

the

optimization

problem

intractable

but

choosing

an

objective

function

is

very

dependent

on

the

applications

and

the

scenario

Thus

achieving

acceptable

performance

for

Figure

Topology

Five

WLAN

devices

and

four

Bluetooth

piconets

Table

Experiment

results

BT

traffic

WLAN

BT

loss

WLAN

loss

Voice

a

particular

system

comes

at

the

expense

of

the

other

system

's

throughput

Therefore

we

believe

that

the

primary

solutions

to

this

problem

lie

in

the

development

of

coexistence

mechanisms

-LSB-

-RSB-

BlueHoc

Bluetooth

Performance

Evaluation

Tool

Open-Source

-LRB-

-RRB-

opensource

bluehoc

-LSB-

-RSB-

Bluetooth

Special

Interest

Group

Specifications

of

the

Bluetooth

system

Vol

v.

B

Core

and

Vol

B

Profiles

-LRB-

December

-RRB-

-LSB-

-RSB-

T.

Ekvetchavit

and

Z.

Zvonar

Performance

of

phase-locked

loop

receiver

in

digital

FM

systems

in

Ninth

IEEE

International

Symposium

on

Personal

Indoor

and

Mobile

Radio

Communications

Vol

-LRB-

-RRB-

pp.

-LSB-

-RSB-

G.

Ennis

Impact

of

Bluetooth

on

direct

sequence

IEEE

Working

Group

Contribution

IEEE

-LRB-

September

-RRB-

-LSB-

-RSB-

D.

Fumolari

Link

performance

of

an

embedded

Bluetooth

personal

area

network

in

Proceedings

of

IEEE

ICC

Helsinki

Finland

-LRB-

June

-RRB-

-LSB-

-RSB-

N.

Golmie

and

F.

Mouveaux

Interference

in

the

GHz

ISM

band

Impact

on

the

Bluetooth

access

control

performance

in

Proceedings

of

IEEE

ICC

Helsinki

Finland

-LRB-

June

-RRB-

INTERFERENCE

EVALUATION

OF

BLUETOOTH

AND

IEEE

b

SYSTEMS

-LSB-

-RSB-

N.

Golmie

R.E.

Van

Dyck

and

A.

Soltanian

Interference

of

Bluetooth

and

IEEE

Simulation

modeling

and

performance

evaluation

in

Proceedings

of

the

Fourth

ACM

International

Workshop

on

Modeling

Analysis

and

Simulation

of

Wireless

and

Mobile

Systems

MSWIM

Rome

Italy

-LRB-

July

-RRB-

-LSB-

-RSB-

I.

Howitt

V.

Mitter

and

J.

Gutierrez

Empirical

study

for

IEEE

and

Bluetooth

interoperability

in

Proceedings

of

IEEE

Vehicular

Technology

Conference

-LRB-

VTC

-RRB-

-LRB-

Spring

-RRB-

-LSB-

-RSB-

IEEE

Standard

IEEE

standard

for

wireless

LAN

Medium

Access

Control

-LRB-

MAC

-RRB-

and

Physical

Layer

-LRB-

PHY

-RRB-

specification

-LRB-

June

-RRB-

-LSB-

-RSB-

A.

Kamerman

Coexistence

between

Bluetooth

and

IEEE

CCK

Solutions

to

avoid

mutual

interference

IEEE

Working

Group

Contribution

IEEE

-LRB-

July

-RRB-

-LSB-

-RSB-

A.

Kamerman

and

N.

Erkocevic

Microwave

oven

interference

on

wireless

LANs

operating

in

the

GHz

ISM

band

in

Proceedings

of

the

IEEE

International

Symposium

on

Personal

Indoor

and

Mobile

Radio

Communications

Vol

-LRB-

-RRB-

pp.

-LSB-

-RSB-

J.

Lansford

A.

Stephens

and

R.

Nevo

Wi-Fi

-LRB-

b

-RRB-

and

Bluetooth

Enabling

coexistence

IEEE

Network

Magazine

-LRB-

September/October

-RRB-

-LSB-

-RSB-

S.

Shellhammer

Packet

error

rate

of

an

IEEE

WLAN

in

the

presence

of

Bluetooth

IEEE

Working

Group

Contribution

IEEE

-LRB-

May

-RRB-

-LSB-

-RSB-

M.K.

Simon

and

C.C.

Wang

Differential

versus

limiter-discriminator

detection

of

narrow-band

FM

IEEE

Transactions

on

Communications

-LRB-

-RRB-

-LRB-

November

-RRB-

-LSB-

-RSB-

A.

Soltanian

and

R.E.

Van

Dyck

Physical

layer

performance

for

coexistence

of

Bluetooth

and

IEEE

b

in

Virginia

Tech

Symposium

on

Wireless

Personal

Communications

-LRB-

June

-RRB-

-LSB-

-RSB-

M.

Takai

R.

Bagrodia

A.

Lee

and

M.

Gerla

Impact

of

channel

models

on

simulation

of

large

scale

wireless

networks

in

Proceedings

of

ACM/IEEE

MSWIM

Seattle

WA

-LRB-

August

-RRB-

-LSB-

-RSB-

S.

Unawong

S.

Miyamoto

and

N.

Morinaga

Techniques

to

improve

the

performance

of

wireless

LAN

under

ISM

interference

environments

in

Fifth

Asia-Pacific

Conference

on

Communications

and

Fourth

Optoelectronics

and

Communications

Conference

Vol

-LRB-

-RRB-

pp.

-LSB-

-RSB-

J.

Zyren

Reliability

of

IEEE

WLANs

in

presence

of

Bluetooth

radios

IEEE

Working

Group

Contribution

IEEE

-LRB-

September

-RRB-

-LSB-

-RSB-

S.

Zurbes

W.

Stahl

K.

Matheus

and

J.

Haartsen

Radio

network

performance

of

Bluetooth

in

Proceedings

of

IEEE

International

Conference

on

Communications

ICC

New

Orleans

LA

Vol

-LRB-

June

-RRB-

pp.

Nada

Golmie

received

the

M.S.E

degree

in

computer

engineering

from

Syracuse

University

Syracuse

NY

in

and

the

Ph.D.

degree

in

computer

science

from

University

of

Maryland

College

Park

MD

in

Since

she

has

been

a

research

engineer

at

the

advanced

networking

technologies

division

at

the

National

Institute

of

Standards

and

Technology

-LRB-

NIST

-RRB-

Her

research

in

traffic

management

and

flow

control

led

to

several

papers

presented

at

professional

conferences

journals

and

numerous

contributions

to

international

standard

organizations

and

industry

led

consor-tia

Her

current

work

is

focused

on

the

performance

evaluation

of

protocols

for

Wireless

Personal

Area

Networks

Her

research

interests

include

modeling

and

performance

analysis

of

network

protocols

media

access

control

and

Quality

of

Service

for

IP

and

wireless

network

technologies

She

is

the

vice-chair

of

the

IEEE

Coexistence

Task

Group

E-mail

nada.golmie@nist.gov

Robert

E.

Van

Dyck

received

the

B.E

and

M.E.E

degrees

from

Stevens

Institute

of

Technology

Hoboken

NJ

in

and

respectively

and

the

Ph.D.

degree

in

electrical

engineering

from

the

North

Carolina

State

University

at

Raleigh

in

Since

June

he

has

been

a

member

of

the

Advanced

Network

Technologies

Division

of

the

National

Institute

of

Standards

and

Technology

Gaithersburg

MD.

Prior

to

that

he

was

an

Assistant

Professor

in

the

Department

of

Electrical

Engineering

the

Pennsylvania

State

University

University

Park

PA.

During

he

was

a

Summer

Faculty

Research

Fellow

at

Rome

Laboratory

His

other

previous

affiliations

include

GEC-Marconi

Electronic

Systems

Wayne

NJ

-LRB-

-RRB-

the

Center

for

Computer

Aids

for

Industrial

Productivity

Rutgers

University

Piscataway

NJ

-LRB-

-RRB-

the

Computer

Science

Corporation

Research

Triangle

Park

NC

-LRB-

-RRB-

and

the

Communications

Laboratory

Raytheon

Co.

Marlborough

MA

-LRB-

-RRB-

His

present

research

interests

are

in

self-organization

of

sensor

networks

multimedia

communications

and

networking

and

source

and

channel

coding

for

wireless

communications

Amir

Soltanian

received

his

M.S.

degree

from

Sharif

University

of

Technology

Tehran

Iran

in

He

has

been

working

in

the

industry

for

years

doing

research

on

GSM

receivers

Currently

he

is

a

guest

researcher

at

National

Institute

of

Standards

and

Technology

His

current

research

is

the

study

of

the

interference

cancellation

methods

for

the

physical

layer

of

the

Bluetooth

and

WLAN

Arnaud

Tonnerre

is

a

graduate

student

at

the

cole

Nationale

Sup

rieure

des

Telecommunications

-LRB-

ENST

-RRB-

in

Bretagne

France

He

is

currently

doing

an

internship

at

the

National

Institute

of

Standards

and

Technology

-LRB-

NIST

-RRB-

in

Gaithersburg

MD.

He

will

receive

the

Diplome

d'Ingenieur

in

June

His

research

interests

are

in

wireless

personal

area

networks

Olivier

R

bala

received

a

computer

science

degree

from

the

Institut

sup

rieur

d'informatique

de

mod

lisation

et

de

leurs

applications

-LRB-

ISIMA

-RRB-

in

Clermont-Ferrand

France

in

September

He

is

currently

a

Guest

Researcher

at

the

National

Institute

of

Standards

and

Technology

-LRB-

NIST

-RRB-

in

the

advanced

networking

technologies

division

His

research

interests

includes

the

performance

evaluation

of

wireless

networking

protocols

B B O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O B I O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O B I O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O B O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O B O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B O O O O O O B I O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B B O O O O O O O O O O O O O O O O O B I O B I O O O O O B O O O O O O O O B O O O O O O O B I O O B O B O O O O O O B O O O O O O B O O O B O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O B O O O B O O O O O O O O O O O O B B O O O O O B B O O O B B O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O B O O O O O O O O O B B I O O O O O O O O O O O O B O O O O B B I O O O O O O O O B I O O O O O O O O O O O O O O O B I O O O O O O O B O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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O O O O O O O O O O O O O O O O B B I O B O B O O O O O O O O O O O O O O B B I O O O O O O O O O B I O B O O O O O O O O O B O O O O O O O O O O O O O O O B B I O O O O O B O B I O O O O O O O O O O O O O B I O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O B O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O B I O O B O O B O O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O B I O O B O O O O O O O O O B I O B O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B 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O B B I O O O O B B I O O O O O O B O O O O O B O O B O O O O O O O O O O B B I O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B O O O O O O B O O O O O B O O O O O O O O B O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O B O O O O B I O O B O O O O O O O O O O O O O O O O B B O B O O O O O O B O O O O O B O O O O O O B B I O O O B O O O O O O O O O O B O O O O B O O O B B I O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O B B I O O O O O O O O B O O O O O B O B O O O O O O B I O B O O O O O O O O O B O B O O O B O O O O O O B O B O O O O O B O O O O O O B 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O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O

interference
wlan
bluetooth
simulation framework
evaluation
hop rate
topology
wpans
performance degradation
packet loss
offered load