Intro to UWB

8/3/2019 Intro to UWB

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5th Winter School Jan 12-15, 2003UCSD/UCLA/Stanford MURI/ARO

Introduction to UWB

Gian Mario Maggio

CWC/UCSD & STMicroelectronics

Collaborators: David Laney, Lawrence Larson,Luca Reggiani and Larry Milstein

Sources: CWC, Time Domain, Intel, Discrete Time

Communications, STMicroelectronics, INFOCOM


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Outline

What is UWB?

FCC regulatory issues

Advantages/challenges of UWB

Applications of UWB:

Communication

Radar

Tracking/positioning

UWB impulse radio Spread-time UWB

Networking with UWB

UWB industry standards


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What is UWB?

Definition: A signal whose bandwidth is greater

than 500 MHz, or such that its fractional bandwidth:

Note: At Part 15 (a few tens of microwatts total, acrossseveral GHz), powers cannot be reliably measured below

10 dB down points

fh-fl

fh+fl2 0.25where:

fh= upper 10 dB down point

fl = lower 10 dB down point


4/455th Winter School Jan 12-15, 2003UCSD/UCLA/Stanford MURI/ARO

Why UWB?

The motivation for UWB can be understood by looking at the

capacity equation for a Gaussian channel. More bang-for-the-

buck by increasing bandwidth, than increasing power.

Where:

C= Maximum Channel Capacity (bits/sec)B = Channel Bandwidth (Hz)

S= Signal Power (watts)

N= Noise Power (watts)

+=N

SBC 12log

Cgrows linearly with B,

but only logarithmically with S/N

Capacity of a Gaussian Channel:



UWB vs. Current Radios

Power

GPSPCS

ovens, phones

Bluetooth802.11b

HomeRF 802.11a

UWB signal

UWB overlays traditional

radios

Part 15

noise

limit

Frequency GHz

1.0 1.6 1.9 2.4 3.13.1 4 5 6 7 8 9 10.110.1

Other names and brands may be claimed as theproperty of others.



Imperceptible UWB

Co-existence with Licensed Operators:Aggregate interference from

UWB transmissions is undetectable (or has minimal impact) to narrowbandreceivers, i.e. Power Spectral Density is below the thermal noise floor:

UWB 5MHz Noise Floor



UWB vs. 802.11

UWB offers high data rate at close range:

Current industry statusCurrent industry status



Spatial Capacity (1/3)



Brief History of UWB

1969-1984 - Harmuth [Catholic University of America]:

Nonsinusoidal waves for radar and radio communication

1972-1987 - Ross and Robbins [Sperry Rand Corporation]: UWB forradar and communication, tunnel diodes;Van Etten [Rome Air ForceLab]: antenna design, pulse and chirp systems

1980-2000: Fullerton [Time Domain]: Avalanche transistor based systems, antennas, etc.

McEwan [Lawrence Livermore Lab]: Avalanche based systems, receivers,samplers

Morey [Geophysical Survey Systems]: Avalanche based commercial GPR systems

Young et al. [OSU]: GPR systems, Big Ear, antennas, etc.

Beckner et al. [Power Spectra]: Bulk GaAs semiconductor switch


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UWB Companies


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FCC - Regulatory Process


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FCC Limits Indoor (3.1-10.6 GHz)


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Challenges of UWB

Data rate: What are the limitations in throughput for this technology

(can we achieve Gigabits per second)? Interference from NB transmitters: How to alleviate interference

while maximizing efficient use of the spectrum (notch filtering, spreadspectrum, adaptive filtering, etc.)?

Interference to NB receivers: How does UWB waveforms affect otherco-located wireless systems (Bluetooth, WLAN, FWA, 3G cellular)?

Antenna design: Is the RF signal processing well understood?

Multipath: How to capture efficiently the energy from multipath(Rake receivers)?


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Broadband to the Home

POTS

CATV

MMDS

Satellite

Optical DSL

Cable Modem

FTTH


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Applications of UWB (1/3)

Communications: High-speed (~100 Mb/s) and high-

performance wireless networks

High-speed wireless networks (home, office, schools,telemedicine)

Wireless broadband internet access (ultra low power, anywhere,anytime, all the time)

Private radio

Indoor broadband cellular phone Military applications (tactical handheld & network LPI/D radios,

non-LOS LPI/D groundwave communications)


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Radar: High-resolution radar systems

Through-wall imaging and motion sensing radar

Security systems for alarming and tracking movement

Underground imaging

Automotive collision-avoidance sensors

Precision measurement devices

Robotic sensors Aviation safety improvements

Military applications (intrusion detection radars, proximity fuzes,unmanned ground and aerial vehicles)


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Tracking: Ultra-precise positioning systems for seamlessindoor and outdoor tracking

People tracking (tags, smart appliances)

Asset tracking

In-building tracking

Aviation ground tracking

Ultra precise positioning systems (precision navigation, precisionfarming)

Military applications (facility and personnel security, logistics)


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Radar/Tracking (Time Domain)

Proposed TimeTagTM

Design for

Precision Tracking


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UWB Impulse Radio

Sinusoidal, Narrowband

Frequency

Time

Time

Frequency

Impulse, Ultra-Wideband


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Multipath Fading

Short impulse (< 1 nsec typically) prevents destructive interference

Multipath components can be individually resolved Carrier-less nature of waveform results in less fading, even when

pulses overlap

10 meters

5.22 m 5.22 m

Main Path

Reflected Path

t1

- t0

= 1.47 nsec

1.5 m

(floor)


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Transceiver Architecture

Example "narrowband" Transceiver Architecture

Example UWB Transceiver Architecture

Modulator X BPFPA LNA X X LPF Demod.RF

Filter

RF IFRF

Modulator

Pulse

Generator

PA

(optional)

LNA RF

FilterX LPF

Sampler/

Detector

(correlator based receiver)

Pulse

Generator

Data

in

Data

out

Amplitude or position

modulate the pulseDemodulator

Data

in

Data

out

PRF

PRF


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UWB Multiple Access

( ) ( ) ( )( )=

+

=

=

=U

k i

Ns

j

k

ic

k

jfb bTcjTiTtgts1

1

0

t

C(1)=[1 0 0 2] b1=0

C(2)=[0 1 2 0] b2=1

C(3)=[2 2 1 0] b3=0

s(t)

When the number of users is U, the transmitted signal is:


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Spread-Time UWB (1/3)

Where: g(t) is the UWB monopulse (with Fourier transform G(w)), PN(w) is the

pseudo-random sequence, and pA(t) is defined by: ( )

=otherwise,0

AtA-,1tp

A

Achieve multiple-access capability and interference

suppression using spectral encoding.


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Monopulse

Spectrum

Pseudo-random

Sequence

Product

(transmitted signal)

Optical Communications context: Coherent ultrashort light pulse code-divisionmultiple access communication systems, Salehi, Weiner, and Heritage: J.Lightwave Tech., Mar 1990.


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Monopulse

Spectrum

Pseudo-random

Sequence

Product

(transmitted signal)


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Interference Analysis

Interference model: Tone ( ) ( ) += twtI 0cos

where is a random phase uniformly distributed between 0 and .2

Networking with UWB


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Networking with UWB

What UWB offers to wireless networking:

Precise ranging (localization with distributed processing) High robustness for indoor applications

What UWB requires:

Fine power tuning in order to meet power limits

Efficient synchronization algorithms to reduce link set-uptime and synchronization overhead

Optimal solution for UWB networks:

power-efficient, location-based routing strategy


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Reference Model (1/2)

Coverage area: all nodes are within reach of each other:


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Reference Model (2/2)

multi-hop link (3 hops)

terminal

2

3

1

direct link

destination

terminal

source

Connection between a source and destination terminal through a

direct path i.e. one hop link, and a multi-hop link made of3 hops

P th S l ti St t i


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Path Selection Strategies

Absolute minimization of unitary cost function:

Metrics = Number of hops

Absolute minimization of power-related cost function:

Metrics = CostNew approaches:

Constrained minimization of number of hops :

Metrics = f (Number of hops, Cost)

Constrained minimization of Network Cost Function:

Metrics = f (Cost, Number of hops)

N t k T l


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Network Topology

Resulting network topology strictly depends on the adopted

path selection strategy

We expect network topology to resemble one of the threefollowing models:

Regular network: each node is connected mainly with its short-distanceneighbours

Random network: each node is connected with nodes positioned allover the network, at any distance

Small world network: intermediate between the two previous models -

combines their properties

Wh S ll W ld?


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Why Small-World?

Short path length

Each node is efficiently connected to all possibledestinations in the network

High cliquishness

Robustness to local link failure, thanks to high number

of alternative local links

Al ith f P th S l ti


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Algorithms for Path Selection

SingleHop algorithm Set-up a connection only if a direct link is possible, i.e. if adding the

cost of the direct link does not violate the maximum NCF

MultiHop algorithm

Selects the path at lower cost considering all possible paths in thenetwork

Constrained-MultiHop algorithm Selects the path at lower cost in a subset of all possible paths in the

network

Small-World algorithm Set-up a direct link if possible, otherwise use a multi-hop path


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IEEE 802 Organization


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IEEE 802 Organization

VICE CHAIR

Paul Nikolich

RECORDING SEC

Howard Frazier

EXEC SEC

Buzz Rigsbee

TREASURER

Bob Grow

802.1

BRIDGING/ARCH

Bill Lidinsky

802.2

LLC

Dave Carlson

802.3

CSMA/CD

Geoff Thompson

802.4

TOKEN BUS

Paul Eastman

802.5

TOKEN RING

Bob Love

802.6

DQDB WAN

Jim Mollenauer

802.7

BROADBAND

(802.14 Res)

802.8

FIBER TAG

Chip Benson

802.9

ISLAN

Dhad. Varnen

802.10

SECURITY

Ken Alonge

802.11

WIRELESS LAN

Stuart Kerry

802.12

DEMAND PRIORITY

Pat Thaler

802.14

CABLE-TV

Robert Russell

802.15

WIRELESS PAN(TM)

Bob Heile

802.16

WIRELESS MAN

Roger Marks

ECSG

RPRSG

CHAIR

Jim Carlo

Executive Officers

= Active

= Hibernation

= Disbanded

= Wireless

WorkingGroupOfficers

802 15


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802.15

Standards for Wireless Personal Area Networks (WPANs):

Short-range, Low Power, Low Cost, Small networks (e.g. 8-16 nodes) 802.15.1 (Standard)

IEEE Standard of Bluetooth Specification

802.15.2 (Recommended Practice)

Model and Facilitate Coexistence of WPAN & WLAN devices

802.15.3 (Standard)

A High-Rate (> 20 Mbps) WPAN

Radio2 Study Group

Track Bluetooth2 and recommend an action.

Low Rate Study Group

Raw Data Rate = 2Kb/sec to 200Kb/sec

IEEE802.15.SG3a


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An Alternate PHY for the IEEE802.15.3 MAC

Applications:

i. Video Conferencing

ii. Home Theater

iii. Interactive Applications

iv. Content Downloading

MAC is the IEEE802.15.3 MAC

i. Time slotted TDMA with QoS guarantees

ii. Piconet centralized controller with

peer-to-peer communications

IEEE802 15 SG3a Specs (1/2)


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IEEE802.15.SG3a Specs (1/2)

110 Mbps @ 10 meters

200 Mbps @ 4 meters

i. 8% PER for 1024 octet frames

ii. Measured at PHY SAP (above PLCP)

4 piconet co-operation in close proximity

i. Minor degradation allowed

Coexistence and Interference Rejection

i. Both required for usual list of IEEE802 PHYs

Channel Model for UWB

i. S-V model (work still in progress)

IEEE802 15 SG3a Specs (2/2)


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IEEE802.15.SG3a Specs (2/2)

Power Consumption:

i. 100 mW at 110 Mbpsii. 250 mW at 200 Mbps

iii. Power Save

Emphasis on QoS - target corrected error rate of 10e-9 Form factors

i. Small!

Cost and complexity are concern Supplements to the 802.15.3 MAC to support unique

functionality induced by the alternate PHY

Consideration given to regulatory issues

Web Resources


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Web Resources

www.aetherwire.com/CDROM/Welcome1.html - Papers, book chapters,

patents, and a large bibliography www.multispectral.com/UWBFAQ.html - Ultra-Wideband FAQ

www.multispectral.com/history.html - UWB history

ultra.usc.edu/ulab/ - UltraLab at USC (by Bob Scholtz)

cwc.ucsd.edu Center for Wireless Communications at UCSD www.uwb.org - UWB Working Group

www.uwb.org/Conference/Proceedings.htm - UWB Conference,

Washington, DC, Sept 1999

www.uwb.org/standards.htm - FCC Notice of Inquiry (comments andreplies)

grouper.ieee.org/groups/802/15/ - IEEE802.15 Web Site

Intro to UWB

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