Ultra WideBand Paul Solecki

History of UWB  1962 – Study in time-domain electromagnetics (Ross)  Short Pulse Radar and Communications Systems conceived  1973 – First UWB patent issued  1978 – Developed SPR and CS  1984 – LPI/D developed  1989 – DoD refers to it as UWB  1994 to present – Most work done without classified government restriction

Ultra WideBand  Also referred to as impulse, baseband or zero-carrier technology  Pulses instead of continuous waves  Pulse length on order of sub-nanoseconds in time domain  Result is that it uses a wide swath of bandwidth in frequency domain

Pulse vs. Continuous Wave

Benefits  Mbps rate  Ideal for short range WPANs, < 10m  Virtually NO Multi-path interference  Very low power emission UWB radio – 75nW/GHz,.26mW aggregateUWB radio – 75nW/GHz,.26mW aggregate b radio - 30 – 100mW802.11b radio - 30 – 100mW Bluetooth radio – 1mW-1WBluetooth radio – 1mW-1W  Shannons equation becomes linear with respect to Bandwidth and Power  Simplified architecture, nearly all digital  Small silicon space usage

UWB – Disadvantages  Bad for > 10 Gbps Due to FCC limit of power emissionDue to FCC limit of power emission

UWB - Applications  Wireless Networks – WPANs  Wireless home systems ComputerComputer Entertainment centerEntertainment center  Covert communication  Radar fine resolutionfine resolution AutomotiveAutomotive Ground penetratingGround penetrating  Streaming A/V for PDAsPDAs Digital cameraDigital camera MP3 playersMP3 players  Electronic measuring devices  Electronic positioning devices See through walls etc.See through walls etc.

UWB Standard  IEEE a Task Force  FCC set aside 7500MHz of spectrum for unlicensed use  3.1 GHz GHz  100/200/400 Mbps at 10/4/2m  OFDM vs. DS-CDMA  TI/Intel vs. Motorola/XtremeSpectrum  4.8 GHz is perceived to be the upper band due to current CMOS technology

UWB  FCC spectral mask UWB signals must not exceed threshold of spectral maskUWB signals must not exceed threshold of spectral mask

UWB vs. WiFi

a Debate  Sept – IEEE conference results in 60% approval for OFDM  OFDM vs. DS-CDMA  TI/Intel vs. Motorola/XtremeSpectrum  75% needed for acceptance  Compatibility issues

UWB-OFDM  Multiple Bands in 3.1 GHz – 4.8 GHz  500 MHz slices  Interleave signals

UWB-OFDM Advantages  Cost  Power consumption  Complexity of device  Proven in a

UWB – OFDM Disadvantages  Interference  Time synchronization needed

UWB – DS-CDMA   Direct Sequence Spread Spectrum In a direct sequence system, the transmitted baseband signal is multiplied by a pseudonoise code digital stream.

UWB - DS-CDMA

UWB – DS-CDMA Advantages  Very low interference along ENTIRE spectrum  Avoids potential cross-border interference

UWB – DS-CDMA Disadvantages  Complexity of device  Power use  Cost

UWB vs. Competing Technologies

UWB – Bi-phase Radio system  All Digital !!  No Power Amplifier needed