Ultra-wideband (UWB) Signals

for Communications and Localization

Sinan GeziciAssistant Professor

Dept. of Electrical and Electronics Eng.

Bilkent Universitygezici@ee.bilkent.edu.tr

Ultra-wideband (UWB)• Definition

– (Absolute) bandwidth ≥ 500 MHz

Babs = fH– fL

– Fractional bandwidth ≥ 0.2Bfrac = (fH– fL) / fC ≥ 0.2

Regulations for UWB • FCC in the US allows transmission in 3.1-10.6 GHz

band• Coexists with incumbent systems

– Low power spectral density (-41.3 dBm/MHz)

– Large spreading factors

UWB

UWB Signals• 3 common signaling formats:

– OFDM UWB

– DS-CDMA UWB

– Impulse radio (IR) UWBA train of short duration (sub-nanosecond) pulses with a low

duty cycle

One information symbol

Advantages of UWB (1/2)• High data rate: Large bandwidth increases capacity

• Low power/cost: Simple transceiver architectures with low power consumption are possible

For AWGN channels

Advantages of UWB (2/2)• Precise position estimation (localization): High time

resolutionTransmitted Signal

Reflected Signal

Time=T1

Range = 0.5(T2-T1)c c : Speed of light15 m

Radar Transceiver

Object

Device

• Penetration through obstacles: Large frequency band facilitates penetration through objects

• Low probability of detection: Similar to white noise for other systems

http://www.radarvision.com

Time=T2

Object

Applications (1/2)• Communications

– High data rate: e.g. wireless USB, WPAN

– Low data rate: IEEE 802.15.4a, wireless sensor networks

http://www.soumu.go.jp

Applications (2/2)• Radar and localization

http://www.radarvision.com

Medical applications:

e.g., non-invasive patient monitoring, respiration and heartbeat rate estimation

Other applications:

e.g., thru-wall monitoring, rescue operations after an earthquake.

[E. M. Staderini 2002]