Ultra-Wideband Technology Micro-Electronics Center Sharif University of Technology UWB Ultra-Wideband Technology Ali Fotowat-Ahmady Sharif University of Technology UWB Group: Ali Medi Hajir Hedayati Vahid Mir Moghtadaie Iman Khajenasiri

Outline UWB Introduction UWB Applications and Industries Micro-Electronics Center Sharif University of Technology UWB Outline UWB Introduction UWB Applications and Industries Interference challenges in UWB systems and UWB Transmitter UWB Receivers

Introduction(Definition) Micro-Electronics Center Sharif University of Technology UWB Introduction(Definition) UWB transmitter signal BW: Or, BW ≥ 500 MHz regardless of fractional BW fu-fl ≥ 0.20 ) fu+fl( Where: fu= upper 10 dB down point fl = lower 10 dB down point 2

Micro-Electronics Center Sharif University of Technology UWB FCC Regulations 3.1 10.6 [1] Lic.Tech. Matti Hämäläinen, ”Introduction to existing ultra wideband (UWB) technologies”, UWB_070406.ppt. Since the UWB occupies a large bandwidth, it introduces interference to the coexisting communication systems. The FCC has set strict regulation on the UWB trsmission power, to maintain the interfernce at an acceptable level. So, the first reason to perform spectrum shaping is to fit the PSD of UWB signal with the FCC mask. 0.96

UWB Signals Micro-Electronics Center Sharif University of Technology Impulse Radio (IR) or narrow time-duration pulses multi-band orthogonal frequency-division multiplexing (MB-OFDM)

The key attributes of UWB technology Micro-Electronics Center Sharif University of Technology UWB The key attributes of UWB technology High data rates communication and high-precision ranging applications High multipath and jamming immunity Extremely difficult to detect by unintended users Co-existence capability Low cost, low power and single chip architecture

Pulsed UWB applications Micro-Electronics Center Sharif University of Technology UWB Pulsed UWB applications Communications Short/medium Range Communications Links Radar Ground penetrating radars Through wall radars Imaging and ranging Intelligent Sensors Telemetry Motion Detectors Intelligent Transport Systems Next generation RFIDs Other Medical Applications Indoor localization (GPS assisted)

FCC UWB Device Classifications Micro-Electronics Center Sharif University of Technology UWB FCC UWB Device Classifications Report and Order authorizes 5 classes of devices with different limits for each: Imaging Systems Ground penetrating radars, wall imaging, medical imaging Thru-wall Imaging & Surveillance Systems Communication and Measurement Systems Indoor Systems Hand-held Systems Vehicular Radar Systems collision avoidance, improved airbag activation, suspension systems, etc RTLS

Security and Air force Applications Micro-Electronics Center Sharif University of Technology UWB Security and Air force Applications Preventing the air units from striking each other Micro Air Vehicles (MAV), Each side 15 cm, for security operations

Sensor Networks Applications Micro-Electronics Center Sharif University of Technology UWB Sensor Networks Applications Un-Detectable Control of Borders and Gas &Oil pipelines By using UWB Over Fiber (UOF), extending the range

4-UWB for Localization & Tracking Micro-Electronics Center Sharif University of Technology UWB 4-UWB for Localization & Tracking Medium Bit rate Long Communication Links (>100m) Ranging/Localization in indoor/urban environments Robust against jamming/detection

Localization Micro-Electronics Center Sharif University of Technology UWB Localization Localisation / ticketing / logistics systems for control / safety / navigation in public environments and transportations Communications must be very robust and reliable as the positioning and the data transfer can be related to payment operations

Three Principles of Positioning Micro-Electronics Center Sharif University of Technology UWB Three Principles of Positioning TOA (Time of Arrival) & RTD (Round Trip Delay) TDOA (Time Difference of Arrival) AOA (Angle of arrival)

UWB RFID/ RLTS Technical Attributes Micro-Electronics Center Sharif University of Technology UWB UWB RFID/ RLTS Technical Attributes There are seven key technical attributes that UWB RTLS offers the customer the ability to control their most critical business processes and high-value assets. Small Tag Size Down to 1” x 1” x1” or smaller Long Tag Life Up to 7+ years @ 1Hz Blink Rate High Resolution/ Accuracy Real-time location accuracies of <1 ft with line of sight High Tag Throughput Up to 5000+ tags/ second presence and 2500+ tags/ second locate (in a typical four receiver set-up) High Tag Transmission Rate Up to 200 times/ second possible Excellent Performance in Pulse response operates well in high multipath environments Metallic Environments Long Range Up to 600+ ft line-of-sight with high-gain antenna presence and up to 300 ft between receivers locate

Micro-Electronics Center Sharif University of Technology UWB UWB RFID Advantages Communication and Tracking at same time Security Simple and Low Cost tag

UWB RELATED INDUSTRIES Micro-Electronics Center Sharif University of Technology UWB UWB RELATED INDUSTRIES XtremeSpectrum Time Domain General Atomics AetherWire & Location Multispectral Solutions (MSSI) Pulse-Link Appairent Technologies Pulsicom Staccato communications Intel TI Motorola Perimeter players Sony Fujitsu Philips Mitsubishi Broadcom Sharps Samsung Panasonic

Outline Interference challenges in UWB systems Conventional UWB pulses Micro-Electronics Center Sharif University of Technology UWB Outline Interference challenges in UWB systems Conventional UWB pulses Hermite and proposed UWB pulse Proposed circuit for pulse implementation Simulation results Conclusion

Possible interferers in UWB systems Micro-Electronics Center Sharif University of Technology UWB Possible interferers in UWB systems Most significant interferer 802.11a (5GHz WLAN) Avoiding 802.11a MB-OFDM Eliminating Band #2 IR-UWB & DS-UWB Using UWB lower Band Using UWB upper Band

Effects of Narrowband interferers on UWB system Micro-Electronics Center Sharif University of Technology UWB Effects of Narrowband interferers on UWB system SNR (dB) of UWB in the presence of 802.11a interferer dUWB- (m) in LOS d802.11a 1 3 6 10 15 7 2 -1 5 28 19 14 32 24 20 16 None 51 42 37 33 dUWB- (m) in NLOS d802.11a 1 3 6 10 -6 -17 -25 5 22 -5 -13 37 -8 None 46 29 19 11

Effects of Narrowband interferers on UWB circuit Micro-Electronics Center Sharif University of Technology UWB Effects of Narrowband interferers on UWB circuit IR-UWB covering the whole band → the interferer is in-band → no pre-filtering → corrupted signal!! Easier in MB-OFDM →the interferer is out of band → pre-filter 2nd and 3rd order modulation of interferer UWB receiver desensitization due to large interferer

Effects of UWB on Narrowband system Micro-Electronics Center Sharif University of Technology UWB Effects of UWB on Narrowband system Data rate in the presence of UWB interferer SNR in the presence of UWB interferer d802.11a- (m) in NLOS dUWB 1 3 6 10 31 14 4 -3 5 42 25 15 7 47 30 20 12 None 52 36 26 18 d802.11a- (Mbps) in NLOS dUWB 1 3 6 10 54 9 5 36 48 18 None 12

Solution for In-Band interferers of IR-UWB Micro-Electronics Center Sharif University of Technology UWB Solution for In-Band interferers of IR-UWB Intended UWB pulse IR-UWB, low power, low complexity compare with MB-OFDM Of great interest Covering the whole spectrum can be done by designing such a pulse featuring frequency nulls

Frequency Domain(GHz) Micro-Electronics Center Sharif University of Technology UWB Applicable UWB pulses Time Domain Gaussian derived pulse : Frequency Domain(GHz) All Cosine Functions Without 5 GHz Cosine

Modified Hermite Pulses Micro-Electronics Center Sharif University of Technology UWB Modified Hermite Pulses Hermite polynomials are the finite sum of terms like To be orthogonal Modified Hermite pulse Inherent nulls in the power spectrum of this pulse the main motivation behind this work Complete Coexistence of UWB and the NB system located in the null

2nd order Modified Hermite Micro-Electronics Center Sharif University of Technology UWB 2nd order Modified Hermite Time Domain Frequency Domain(GHz) Modified Hermite Pulse Up-Converted One

Micro-Electronics Center Sharif University of Technology UWB Designed Pulse Designed UWB Pulse The major problem is 5 GHz WLAN, 2nd order Hermit is OK! 2nd order Hermit pulse modified to be implementable in analog circuits

Micro-Electronics Center Sharif University of Technology UWB Circuit Analysis 6 blocks needed: Square function MOS device square law Trans-linear circuits Exponential function Bipolar device MOS device in sub-threshold region Multiplier for mathematical multiplication Mixer for up converting VCO for cosine function An input ramp stage

Micro-Electronics Center Sharif University of Technology UWB Quadratic Function For a fully quadratic function two long channel MOS devices used, each switches in its cycle

Micro-Electronics Center Sharif University of Technology UWB Overall Circuit

Important parameters The input DC biasing determines the current Micro-Electronics Center Sharif University of Technology UWB Important parameters The input DC biasing determines the current R value chosen to keep MOS in saturation The Cosine function determines the null frequency The tuning circuit is placed for fine tuning due to process variation The input ramp determines the BW of the pulse and the number of the nulls in the spectrum

Micro-Electronics Center Sharif University of Technology UWB Simulation results Time domain response Frequency domain response FCC Indoor Mask

Fine tuning of the nulls by the gain of the tuning circuit Micro-Electronics Center Sharif University of Technology UWB Fine tuning of the nulls by the gain of the tuning circuit 20 dB gain increase of tuning circuit Tuning circuit normal gain Input ramp for both

Pulse Characteristics Micro-Electronics Center Sharif University of Technology UWB Pulse Characteristics Pulse Properties Pulse Bandwidth Up to 12 GHz Number of the nulls 2 to 6 nulls in the UWB spectrum Null depth Up to 50 dB Coarse tuning Cosine for up-converting Fine tuning Input ramp voltage, Tuning circuit gain Power consumption Quadratic and exponential functions- 4 mA Multiplier and Mixer- 15 mA

Micro-Electronics Center Sharif University of Technology UWB Conclusion The proposed UWB pulse features frequency nulls in the UWB spectrum The pulse can be coarse or fine tuned by the input ramp voltage, frequency of the cosine function and gain of the tuning circuit As a result no SNR degradation would occur for the NB system located in the null, and the NB system wouldn’t be disturbed

Micro-Electronics Center Sharif University of Technology UWB Conclusion No SNR degradation in UWB system will occur because of no overlapping with NB system NB system in the null would be considered out of band and pre-filtering can be done without any loss of data On chip filtering of the NB system can be done since the Q of the filter is relaxed due to the null existence An IR-UWB transceiver covering the whole spectrum can be accomplished

Future Works Major UWB Limitation Short distance communications Micro-Electronics Center Sharif University of Technology UWB Future Works Major UWB Limitation Short distance communications UWB over Fiber UWB pulse design with notches in Optics

New Design of UWB Receiver Micro-Electronics Center Sharif University of Technology UWB New Design of UWB Receiver

Micro-Electronics Center Sharif University of Technology UWB TX and RX Block Diagram Main challenge in UWB is in Rx: large bandwidth, high required timing precision difficult signal synchronization Main difference of all RX topologies Location of ADC ( in A , B or C in RX Block Diagram) Matched filter correlation (coherent or incoherent) Pulse template

Receiver topologies Fully digital (FD) Transmitted reference (TR) Micro-Electronics Center Sharif University of Technology UWB Receiver topologies Fully digital (FD) 4 bit : high power 1 bit : low power but bad performance when interference Transmitted reference (TR) Energy detector(ED) Data pulse as its own reference Self-mixing of the noisy input signal Impossible BPSK (PPM) Flashing high SNR low interference environments Quadrature Analog correlation (QAC)

Micro-Electronics Center Sharif University of Technology UWB

Micro-Electronics Center Sharif University of Technology UWB Flashing Receiver topology

Quadrature Analog correlation (QAC) Micro-Electronics Center Sharif University of Technology UWB Quadrature Analog correlation (QAC) Quadrature Analog correlation receiver (QAC) Windowed sine wave as a template in matched filter to avoid complexity (Loss  1dB) (Input)(LO)+(windowed integration) = Correlation with windowed sine wave( template)

Micro-Electronics Center Sharif University of Technology UWB Simulation Results Bad performance of 1 bit FD in the strong interferer increasing loss of the QAC in more dense multipath channels, due to its simplified channel compensation the excellent performance of the QAC receiver in interference dominated environments

Comparison between Different Topologies Micro-Electronics Center Sharif University of Technology UWB Comparison between Different Topologies Figure of Merit: “Energy/Useful Bit” or EPUB (the best parameter to tare-off between power and performance) Four channel models 1 path: LOS G: Gaussian Noise i: Interference QAC receiver has excellent EPUB.

Implementation challenges Micro-Electronics Center Sharif University of Technology UWB Implementation challenges Template misalignment and clock offset Low Sensitivity and jitter up to 300ps Compensation of Clock offset by tracking the rotation of (I,Q) constellation vector in digital IQ imbalance up to 10 degree can be tolerated Phase noise out-of-band interferers to be mixed inside band Dither around the ideal point in the constellation (noise for tracking loop) ADC resolution

Design Considerations Micro-Electronics Center Sharif University of Technology UWB Design Considerations Flexibility in operation Operation with a 0-960MHz and 3-5GHz front-end Pulses with a bandwidth from 500MHz to 2GHz Pulse period from 20nsec to 200nsec PN code 1 to 63 pulses per bit(PG:0dB to 18dB) Data-rates from 80kbps to 50Mbps Operation phases Acquisition Phase: Channel estimation, Synchronization , RX-TX Clock-offset estimation. Detection Phase: detect the data, clock-offset and tracking

Micro-Electronics Center Sharif University of Technology UWB Measurement Results Implementation of QAC receiver in 0.18µm

Acquisition Phase QAC in multipath Micro-Electronics Center Sharif University of Technology UWB Acquisition Phase Search for the best window position Search for the correct code phase for this window only QAC in multipath Performance loss in multipath channels Loss Compensation by multi-window integration

Communication and Sub-cm Ranging Micro-Electronics Center Sharif University of Technology UWB Communication and Sub-cm Ranging

Thanks for your attention Micro-Electronics Center Sharif University of Technology UWB Thanks for your attention