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UMIACS/LTS Seminar March 17, 2004 Overview of Ultra Wide Band (UWB) Impulse Radio Dr. Jay Padgett Senior Research Scientist Telcordia Technologies/ Applied Research Wireless Systems and Networks [email protected]

Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

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Page 1: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

UMIACS/LTS SeminarMarch 17, 2004

Overview of Ultra Wide Band (UWB)Impulse Radio

Dr. Jay PadgettSenior Research Scientist

Telcordia Technologies/ Applied ResearchWireless Systems and Networks

[email protected]

Page 2: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

2 What is Ultra Wide Band?� FCC definition of UWB signal: bandwidth is at least 20% of

center frequency, or a bandwidth of at least 500 MHz� Bandwidths can exceed 1 GHz� Example: Pulsed UWB signal (pulse width: 0.5 ns).

f (GHz)0 1 2 3 4 5

Φ(f

) / Φ

max

(dB

)

-50

-40

-30

-20

-10

0

τ = 0.5 ns

Signal is a sequence of short pulsesPulse energy spectrum

� The large UWB passband spans the operating frequencies of many existing licensed services� Interference concerns: UWB to narrowband systems (main

concern of FCC, NTIA), narrowband-to-UWB interference (UWB design issue)

Page 3: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

3 Brief FCC / UWB History� FCC motivation: encourage development of potentially useful

new technology without causing harmful interference to existing services and devices� Sequence of FCC Notices and Orders

– Notice of Inquiry in September 1998– Notice of Proposed Rule Making, June 2000– First Report and Order, April 2002: made legal unlicensed operation

of UWB devices subject to certain restrictions– Reconsideration Order and Further NPRM, March 2003: responsive

to Petitions for Reconsideration filed in response to the first R&O

� FCC categorizes its approach to legalizing UWB “conservative” with respect to preventing harmful interference to other devicesand services. FCC has promised further evolution to UWB Rules� Allowed UWB emission levels are less than or equal to the level

allowed for unintentional radiators such as computers and other electronic devices (-41.3 dBm/MHz).

Page 4: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

4 FCC General UWB Emission Limits

Frequency in GHz

1 2 3 4 5 6 7 8 9 10 11 12

UW

B e

mis

sio

n li

mit

in d

Bm

/MH

z

-80

-70

-60

-50

-40

IndoorHandheld

UWB Passband (3.1 to 10.6 GHz)1.99 GHz

1.61 GHz

−75.3 dBm

−51.3 dBm−53.3 dBm

−61.3 dBm−63.3 dBm

−41.3 dBm

960MHz

Page 5: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

5 Applications: DARPA’s NETEX Program

� Phase I: Gain understanding of effects of UWB system operation on existing narrowband spectrum users– Testing (NAVAIR/Pax River): 16 legacy system, 39 modes, 1600

tests completed.– Modeling/Simulation (Telcordia) details below– UWB propagation and channel modeling (Virginia Tech)

� Phase II: (DARPA/ATO BAA 03-20, Industry Day April 7 ‘03)– Push UWB physical layer design to the point where it is capable of

reliably supporting advanced LPD, ranging, location and networking protocols

– Develop algorithms, protocols, and distributed control for robust, scalable ad hoc UWB networking

– Demonstrate 20-node hand held radios, 50-node video network, and 50-node radar sensor integrated into high data rate short range network.

Objective: Develop military UWB sensors and communications systems for operation in extreme environments

http://www.darpa.mil/ato/solicit/NETEX/documents.htm

Page 6: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

6 UWB: An Undesired Result

Page 7: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

7 UWB Interference Modeling

( )fG

( ) ( )∑∞

−∞=

−=k

kTtgtx ( )ty

victim receiver or measurement instrument (e.g., spectrum analyzer) impulse response (baseband equivalent)UWB impulse train receiver

response

( )thb

?t

( )tg

f

( )fH

f

tWhat is the effective interference power due to the UWB signal, as seen by the non-UWB receiver?

Page 8: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

8 Victim Receiver Model and Interference Filtering

f0 f−f0

Receiver Passband

UWB PulseEnergy Spectrum

RF IF1

~ LO1

f0 fIF1IF2

~ LO2

fIF2Detector/DemodulatorCircuitry

HIF(f )

UWB Pulse Sequence IF Impulse Response (envelope shown)

Page 9: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

9 Time Hopping PSD Example: Partial-Frame 2-ns Dithering

f0 (filter center frequency), GHz

0 1 2 3 4 5

filte

r out

put p

ower

, dB

m

-60

-50

-40

-30

-20

-10

M = 10 time hopping binsεc = 2 ns bin separationPuwb = 10 dBmR = 10 MHz pulse rateBIF = 1 MHz IF bandwidth

Page 10: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

10 Closeup – with Simulation Results

f0 (filter center frequency), GHz

1.4 1.5 1.6

filte

r out

put p

ower

, dB

m

-60

-50

-40

-30

-20

-10

ModelSimulation

M = 10εc = 2 nsPuwb = 10 dBmR = 10 MHzBIF = 1 MHz

Page 11: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

11 Simulation – Zero Span – 1.46 GHz

time in microseconds

0 20 40 60 80 100

filte

r out

put p

ower

in d

Bm

-60

-50

-40

-30

-20

-10

M = 10, εc = 2 ns, Puwb = 10 dBmR = 10 MHz, BIF = 1 MHzf0 = 1.46 GHz

f0 (filter center frequency), GHz

1.4 1.5 1.6

filte

r out

put p

ower

, dB

m

-60

-50

-40

-30

-20

-10

ModelSimulation

M = 10εc = 2 nsPuwb = 10 dBmR = 10 MHzBIF = 1 MHz

Page 12: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

12 Simulation – Zero Span – 1.47 GHz

time in microseconds

0 20 40 60 80 100

filte

r out

put p

ower

in d

Bm

-60

-50

-40

-30

-20

-10

M = 10, εc = 2 ns, Puwb = 10 dBmR = 10 MHz, BIF = 1 MHzf0 = 1.47 GHzf0 (filter center frequency), GHz

1.4 1.5 1.6

filte

r out

put p

ower

, dB

m

-60

-50

-40

-30

-20

-10

ModelSimulation

M = 10εc = 2 nsPuwb = 10 dBmR = 10 MHzBIF = 1 MHz

Page 13: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

13 Simulation – Zero Span – 1.48 GHz

time in microseconds

0 20 40 60 80 100

filte

r out

put p

ower

in d

Bm

-60

-50

-40

-30

-20

-10

M = 10, εc = 2 ns, Puwb = 10 dBmR = 10 MHz, BIF = 1 MHzf0 = 1.48 GHzf0 (filter center frequency), GHz

1.4 1.5 1.6

filte

r out

put p

ower

, dB

m

-60

-50

-40

-30

-20

-10

ModelSimulation

M = 10εc = 2 nsPuwb = 10 dBmR = 10 MHzBIF = 1 MHz

Page 14: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

14 Simulation – Zero Span – 1.5 GHz

time in microseconds

0 20 40 60 80 100

filte

r out

put p

ower

in d

Bm

-60

-50

-40

-30

-20

-10

M = 10, εc = 2 ns, Puwb = 10 dBmR = 10 MHz, BIF = 1 MHzf0 = 1.5 GHz

f0 (filter center frequency), GHz

1.4 1.5 1.6

filte

r out

put p

ower

, dB

m

-60

-50

-40

-30

-20

-10

ModelSimulation

M = 10εc = 2 nsPuwb = 10 dBmR = 10 MHzBIF = 1 MHz

Page 15: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

15 Example: PSD of a Swept-PRF Signal

t

r(t)

t

r(t)pulse rate

rd

2T

2T

r

( )22T

tT

atrtr ≤<−+=

Tra d2=

( ) ( )∑+−=

−=M

MnnTttv

1

δ

( )a

TnarrTn

42 22 +++−=

( ) ∑+−=

−=M

Mn

fTj nefV1

Page 16: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

16 Swept PRF PSD and Approximation

frequency (MHz)

0 200 400 600 800 1000

mill

iwat

ts

0

1

2

3

4

exactfirst-order analytic approximation

Swept PRF100 MHz average PRF100 kHz sweep rate4 MHz PRF span (98 to 102 MHz)1 watt total average power1.05 GHz pulse bandwidth (rectangular spectrum)

Page 17: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

17 Closeup of Swept PRF Spectrum

frequency (MHz)

580 590 600 610 620

mill

iwat

ts

0.0

0.2

0.4

0.6

0.8

1.0

exactfirst-order analytic approximation

Swept PRF100 MHz average PRF100 kHz sweep rate4 MHz PRF span (98 to 102 MHz)1 watt total average power1.05 GHz pulse bandwidth (rectangular spectrum)

Page 18: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

18 Individual Tones of the Swept PRF PSD

frequency (MHz)

585 586 587 588 589 590 591 592 593 594 595

mill

iwat

ts

0.0

0.2

0.4

0.6

0.8

1.0

exactfirst-order analytic approximation

Swept PRF100 MHz average PRF100 kHz sweep rate4 MHz PRF span (98 to 102 MHz)1 watt total average power1.05 GHz pulse bandwidth (rectangular spectrum)

Page 19: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

19 UWB Effects on Receiver Performance� is the ratio of the pulse rate to the IF bandwidth� There are 3 primary interference cases:

– , which gives pulsed interference to the detector– with constant pulse rate, which can give a tone

within the passband– with dithering or modulation, which can give a

noise-like signal� The first two cases were explored for fixed-frequency

digital communications receivers and for an analog FM receiver. The third case, in the limit, gives results similar to those of Gaussian noise, which are well-known.�With Nu > 1, there can also be a combination of a tone and

noise (as seen previously).� Results are calculated based on the average UWB

interference power within the receiver passband.

uN

1≤uN1>uN

1>uN

Page 20: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

20 Modeling the Test Procedure for an FM Receiver

Carrier-to-interference ratio (CIR), dB

-10 0 10 20 30

Bas

eban

d SI

NA

D (d

B)

0

10

20

30

40

Nu = 0.1

Nu = 1.0

Nu = 0.01

Gaussian noise

∆f = 2.4 kHzfm = 1 kHzBIF = 30 kHzBbb = 3 kHz

Nu = PRF ÷ IF bandwidth

Page 21: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

21 Analysis vs. dB-Average Test Results (FM)

Test Waveform (TW) Number

1 2 3 4 5 6

CIR

for

10 d

B S

INA

D r

ecei

ver

upse

t, dB

-5

0

5

10

15

20

dB average from measurementsanalysis

Gaussian noise

Page 22: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

22 UWB into a Noncoherent FSK Receiver

-20 -10 0 10 20 3010

-4

10-3

10-2

10-1

100

SIR (dB)

BE

RNu=0.01

Nu=0.02

Nu=0.05

Nu=0.10

Nu=1.00

2exp

21

BER AWGN Equivalent

SIR

-20 -10 0 10 20 3010

-4

10-3

10-2

10-1

100

SIR (dB)

BE

RNu=0.01

Nu=0.02

Nu=0.05

Nu=0.10

Nu=1.00

-20 -10 0 10 20 3010

-4

10-3

10-2

10-1

100

-20 -10 0 10 20 3010

-4

10-3

10-2

10-1

100

SIR (dB)

BE

RNu=0.01

Nu=0.02

Nu=0.05

Nu=0.10

Nu=1.00

2exp

21

BER AWGN Equivalent

SIR

Page 23: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

23 Coherent PSK – Comparison of Rates

-5 0 5 10 15 10

-6

10 -5

10 -4

10 -3

10 -2

10 -1

10 0

SINR (dB)

BE

R

I/N = -30 dB I/N = 0 dB I/N = 30 dB

25.0 :Red =uN

1.0 :Green =uN05.0 :Blue =uN

u

u

NN

log10 SINR BER, lowAt 2BER SINR, lowAt

−≅≅

Page 24: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

24 UWB/Legacy NB Coexistence Example

Rb

UWB data rate (kb/s)

1 10 100 1000

d uwb

Max

imum

UW

B p

ath

dist

ance

(met

ers)

0

200

400

600

800

1000

I/N = 0 dBI/N = 5 dBI/N = 10 dBI/N = 15 dBI/N = 20 dB

f0 = 300 MHzBuwb = 200 MHzdnb = 20 metersFnb = 10 dBFuwb = 1 dB(Eb/N0)uwb = 10 dBA(f0) = 0 dBGTX,uwb = 2 dBGRX,uwb = 2 dBGTX,uwb->nb = 2 dBGRX,nb = 2 dBLTX = LRX = 1 dBDithered pulses

Page 25: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

25 Aggregate Interference – Closed form CDF

( ) ( ) ( ) ( ) ( )∑∞

=

>−

−ΓΓ

−=<=1

0,1sin1

!1

1Prk

k

Z zkzk

kzZzF νπ

ννπ ν

( ) ( ) )interferer(nearest 0exp >−= − zzzFZν

10 log z

-10 0 10 20 30P

{ Z

< z

} [

perc

ent]

Dis

trib

utio

n of

nor

mal

ized

ag

greg

ate

inte

rfer

ence

pow

er

0.1

1

10

305070

90

99

Multiple interferers

Nearest single interferer

γ = 4.0γ = 3.5γ = 3.0

• Uniformly random distribution of interfering transmitters• Equal power• No exclusion zone

Page 26: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

26 IS-95 PCS Blocking vs. UWB Density

ρ (active UWB transmitters/m2)

0.00 0.05 0.10 0.15 0.20

Pb (

perc

ent)

blo

ckin

g pr

obab

ility

aver

aged

ove

r cel

l are

a an

d U

WB

-to-

PCS

dist

ance

0

20

40

60

80

100

Non-uniform distance distributionγ = 3.5

ΦTXuwb = −50 dBm/MHz

−55 dBm/MHz

−60 dBm/MHz

−65 dBm/MHz

ρ (active UWB transmitters/m2)

0.00 0.05 0.10 0.15 0.20

Pb (

perc

ent)

blo

ckin

g pr

obab

ility

aver

aged

ove

r cel

l are

a an

d U

WB

-to-

PCS

dist

ance

0

20

40

60

80

100

Uniform distance distributionγ = 3.5

ΦTXuwb = −50 dBm/MHz

−55 dBm/MHz

−60 dBm/MHz

−65 dBm/MHz

r (meters)

0 1 2 3 4 5 6

f d(r)

prob

abili

ty d

ensi

ty fu

nctio

n fo

rdi

stan

ce to

nea

rest

UW

B tr

ansm

itter

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

ρ = 0.1 active UWB transmitters/m2

Non-uniform

Uniform

Truncated uniform (d0 = 1 meter)

Probability density functions for minimum UWB to PCS handset distance

These curves show the average percentage of handsets blocked on the downlink as a function of UWB deployment density and transmit power spectral density

Page 27: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

27 C/I with Aggregate Interference� Desired signal to NB receiver Rayleigh-faded (terrestrial

multipath).� UWB transmitters uniformly randomly distributed spatially, no

fading of interfering signals (short distances).� May be an “exclusion zone” surrounding victim receiver within

which there will be no UWB transmitters.

Desired NB transmitter

Rayleigh-faded signal path

exclusion zone(no UWB transmitterswithin this area)

dmin

narrowband receiver

Page 28: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

28 C/I CDF with Aggregate UWB Interference and no Exclusion Zone

-40 -30 -20 -10 0 10 20

Pr( C

nb/ I

UW

B <

Λ),

perc

ent

0.1

1

10

30

50

70

90

99

99.9

99.99

γ = 2.5γ = 3γ = 3.5γ = 4

Monte Carlo, γ = 3Nearest interferer, γ = 3

dB , nbX

Λ

22

1exp1Pr

2

>

−Γ

Λ−−=

Λ< γ

γ

γ

nbUWB

nb

XIC

( ) 2 :ionnormalizat γπρα atx

nbnb P

CX =

Page 29: Overview of Ultra Wide Band (UWB) Impulse Radio · 19 UWB Effects on Receiver Performance is the ratio of the pulse rate to the IF bandwidth There are 3 primary interference cases:

29 The Larger Picture: UWB – Challenges, Questions, and Opportunities Going Forward

� Design of UWB radios that can operate adaptively in the presence of strong in-band narrowband signals.� UWB networking: MAC layer design, ad hoc routing protocols,

QoS management, especially with narrowband interference.� Applications – what is UWB best suited for (military and

commercial)?– Radar/localization– Data networking?– Sensors?– Integrated applications (e.g., localization + communications).

� Can UWB be used to provide high data rate hotspots with connectivity to CMRS networks?� Can UWB be used to increase the accuracy of E-911 indoors?