UWB (Ultra Wideband) Communication System 長庚電機通訊組 碩一 張晉銓 指導教授 : 黃文傑博士

Outline Introduction to UWB Application of UWB UWB Spectrum FCC UWB Emission Limit Avoiding Interfering With Other Users Conclusion

UWB and 60 GHz radios potentially extend the range of application of radio technology Carrier Frequency (GHz) Peak Data Rate (bps) 1 G 100 M 10 M 1 M 100 k 10 k HDTV motion picture, Pt.-to-Pt. links NTSC video; rapid file transfer MPEG video; PC file transfer Voice, Data Cellular 3G b 60 GHz Pt.-to-Pt. 60 GHz WLAN Bluetooth a ZigBee UWB

FF Introduction to UWB 1/4 Extremely short pulses in the time domain Large bandwidth in the frequency domain Fractional bandwidth=( f H - f L )/ f C > 25% or total bandwidth > 1,5 GHz time / s Amplitude frequency / Hz Amplitude S B - Technology -

Introduction to UWB 2/4 advantage High data rates Low transmission power (Bluetooth:1Mbps,10m,1mW UWB: 1Mbps,10m,10 ㎼ ) Multipath immunity Simple implementation, low cost High spatial capacity (bps/m 2 ) - Technology- disadvantage Short operating ranges Interference with other licensed, ”narrowband” systems

Introduction to UWB 3/4 FCC(Federal Communication Commission) approved the sale of UWB products in the United States under certain limits in February 2002 UWB devices are allowed to work on very low power levels to avoid interference - Regulations -

Introduction to UWB 4/4 Automotive collision-detection systems Medical imaging Through-wall imaging Ground-penetrating radar Communications devices - Applications -

Application Scenarios

UWB Spectrum FCC ruling permits UWB spectrum overlay Bluetooth, b Cordless Phones Microwave Ovens GPS PCS a -41 dBm/Mhz “Part 15 Limit” UWB Spectrum Frequency (Ghz) Emitted Signal Power  FCC ruling issued 2/14/2002 after ~4 years of study & public debate  FCC believes current ruling is conservative

FCC UWB Emission Limit for Outdoor Handheld Systems

FCC UWB Emission Limit For Indoor Systems

Information Modulation Pulse Position Modulation (PPM) Pulse Amplitude Modulation (PAM) On-Off Keying (OOK) Bi-Phase Modulation (BPSK) Pulse length <1ns; Energy concentrated in 2-6GHz band; Power < 10uW

Main data modulation schemes used for UWB systems Time hopping pulse position modulation (TH- PPM) Direct spread code division multiple access (DS-CDMA) Subband (SB) UWB (Intal)

Avoiding Interfering With Other Users Co-existence through very low power transmission: Operate so that aggregate Interference from UWB Transmissions is “Undetectable” (or Has Minimal Impact) to Narrow-Band Receivers. UWB Thermal (kT) Noise Floor

Conclusion 1.High spatial capacity (bps/m 2 ) 2.Low power (Bluetooth:1Mbps,10m,1mW UWB: 1Mbps,10m,10 ㎼ ) 3.Low cost, simple implementation 4.multi-user interference 5.multiple-access interference 6.Synchronization problems 7.The hardware problem of high frequency in unlicensed band EX:>5GHz GAIN TX CLK ADC DIGITAL

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