ultra wide band (uwb)

Ultra Wide Band (UWB)Mohammad DayehComputer and Communication Engineer

Outline

Outline

What is UWB?

Why UWB?

How it works?

Conclusion

What is UWB?Introduction & Definition

Definition – What is UWB?Ultra-Wide Band (UWB) is a communication technology used in wireless networking to achieve high bandwidth connections with low power spectral density.

high data throughput for communications devices

high precision for location and imaging devices

high resolution for sensing devices

ultra low power (microwatts)

limited interference with conventional radio systems

short signal pulses over a broad spectrum

high wireless data rates in excess of 100Mbit/s (480 Mbps up to 1.6 Gbps at distances up to a few meters)

data rates drop considerably at longer distances

FCC Definition

Fractional Bandwidth > 20% of fc

fH : higher 10dB down pointfL : lower 10db down pointfc : central frequency

Bandwidth > 500 MHz

Example:fL=1GHz and fH=3GHz → FB = 1 GHz

UWB Spectrum

UWB is a form of extremely wide spread spectrum where RF energy is spread over gigahertz of spectrum

UWB signals can be designed to look like imperceptible random noise to conventional radios

Narrowband (30kHz)

Wideband CDMA (5 MHz)

UWB (Several GHz)

Frequency

Part 15 Limit( -41.3dBm/Hz )

Unlicensed Spectrum

Although UWB technology operates at the same or lower power levels currently allowed for numerous applications under the FCC’s unlicensed Part 15 rules, a change of the rules is needed to accommodate this new form of wireless technology.

Basic requirement of Part 15: Thou shalt not create harmful interference.

1 2 3 4 5 6

Pow

er

Frequency (GHz)

Part 15

2.4 GHz UNII Bands

Unlicensed National Information Infrastructure

Principles of UWBTime Domain

Extremely short pulses

Very low duty cycle

Frequency Domain

Ultra wide spectrum Low power spectral density Acceptable interference with

other users

Why UWB?Advantages and Applications

Why UWB - Advantages Spectrum reuse

Use frequencies from 3.1 to 10.6 GHz coexist with other users (sharing spectrum)

High data rate in short range, high throughput 500 Mbps at 10 feet

Multipath immunity Path delay >> pulse width

Low power Baseband modulation (no carrier) Long battery life of portable devices

Low cost and single chip architecture Nearly all digital, simple analog module Silicon based, standards-based radios

Non-interfering to other communication systems It appears like noise for other systems

ThroughputUWB throughput between 802.11a and 802.11b

Low Power UWB Comparable to High Power Wireless Systems

Communications

Ultra Wide Band technology enable wide variety of applications

Intelligent Sensors

Radar Medical Applications

Ground Penetrating

RadarWireless PAN Telemetry

Replace cables between devices

Biofeedback-based

rehabilitation

Home Applications

Through-Wall Radar

Intelligent Transport System

Intelligent Driving and Parking Aids

Medical Imaging

Military Communicatio

ns

Share live multimedia

content between

devices at high data rate

Why UWB - Applications

Automotive Radar

Tank Level Probing Radar

High Speed Wireless USB

Wireless High Definition

Video

Position location and

tracking

Cable Free Environment

How UWB works?Multiple Access TechniquesModulation SchemesTransmitter and Receiver

Multiple Access Techniques

Time Hopping → TH-UWB

Direct Sequence → DS-UWB

Time Hopping: TH-UWB

Ns = 6 (6 frames per symbol) Time Hopping sequence = {2,1,2,3,1,0} Tf = 4Tc

Time Hopping: TH-UWB (continue)

Direct Sequence: DS-UWB

Modulation Schemes

Pulse Position Modulation (PPM)

Binary Phase Shift Keying (BPSK)

Bi-Orthogonal Keying (BOK)

Pulse Amplitude Modulation (PAM)

On/Off Keying (OOK)

Modulation ExamplesPulse Position Modulation (PPM) Usually used with TH-

UWB

Example: 4-ary PPM with data 01

Bipolar Signaling (BPSK) Very energy efficient Usually used in TH-UWB and

DS UWB

Example: BPSK with data 1

Bi-Orthogonal Keying (BOK) PPM + BPSK Used in Std 802.15.3

Example: 4-ary BOK with data 10

Modulation ExamplesPulse Amplitude Modulation (PAM) Poor energy efficiency

Example: 4-ary PAM with data sequence: 01, 11, 00, 10

On/Off Keying (OOK) Simple implementation Poor energy efficiency

Example: OOK with data sequence: 1, 0, 0, 1

Transmitter and Receiver

Standards: Range and Data rate

WLAN™IEEE 802.11

WPAN™IEEE 802.15

WMAN™IEEE 802.16

802.15.1“Bluetooth”

802.15.3“High Data Rate” MAC & 2.4 GHz PHY

Task Group 3aAlt PHY (UWB)

802.15.4“Zigbee” 2.4 GHz

LAN/MAN Standards Committee (Wireless Areas)

802.15.2Coexistence

MBWAIEEE 802.20

Regulatory TAGIEEE 802.18

Coexistence TAGIEEE 802.19

Study Group 4a(UWB?)

Standardization

Wireless Personal Area Networks using UWB as PHY options IEEE standard of 802.15.3a for high data rate IEEE standard of 802.15.4a for low data rate

IEEE 802.15.3ao DS-UWB vs. MB-OFDM-UWBo Proposal with drawn on Jan 2006o Market will decide the surviving technology

IEEE 802.15.4a (Draft)o Communicationso High precision ranging and locationo In progress

Conclusion

Conclusion

UWB is currently an interesting topic for researchers and is at the stage of development.

A radio platform that connects seamlessly with the existing networking protocols and cost effectively enables connectivity solutions between CE peripherals will shift the home entertainment environment. It will enable multiple usage models from cable replacement to the high data rate streaming of video and audio and other entertainment media.

Q & AAny Question? Comments? Suggestions?

The End