ultra wide band radio technology (uwb)(b-tech seminar report)

A SEMINAR REPORT ON

RF transmission based on Microwave UWB

Submitted in partial fulfilment of the requirements for the

award of the degree of

BACHELOR OF TECHNOLOGY

In

ELECTRONICS AND COMMUNICATION ENGINEERING

Submitted by

VINOD V: 07402144

DEPARTMENT OF ELECTRONICS AND COMMUNICATION

ENGINEERING

SREE CHITRA THIRUNAL COLLEGE OF ENGINEERING,

THIRUVANANTHAPURAM 695 018.

NOVEMBER 2010

SREE CHITRA THIRUNAL COLLEGE OF ENGINEERING,

THIRUVANANTHAPURAM - 695 018.

DEPARTMENT OF ELECTRONICS AND COMMUNICATIONENGINEERING

CERTIFICATE

Certified that seminar work entitled “RF transmission based on Microwave UWB” is a

bonafide work carried out in the seventh semester by “VINOD V (07402144)” in partial

fulfilment for the award of Bachelor of Technology in “ELECTRONICS AND

COMMUNICATION ENGINEERING” from University of Kerala during the

academic year 2010-2011, who carried out the seminar work under the guidance and no

part of this work has been submitted or published any where earlier for the award of any

degree.

SEMINAR CO-ORDINATOR HEAD OF THE DEPARTMENT SUBHA V S.VAIDYANATHAN Lecturer, Professor, Department of ECE Department of ECE SCT College of Engineering SCT College of Engineering Thiruvananthapuram-18 Thiruvananthapuram-18

ACKNOWLEDGEMENT

I owe a great many thanks to a great many people who helped and supported

us during the making of this seminar. My deepest thanks to Ms Subha.V, lecturer in

Electronics and Communication Engineering, Sree Chitra Thirunal College of

Engineering, Trivandrum, the seminar co-ordinator for guiding and correcting various

documents with attention and care. They have taken pain to go through the seminar and

make necessary corrections as and when needed.

I gratefully obliged to thank Prof. S.Balachandran, Principal, Sree Chitra

Thirunal College of Engineering, Trivandrum and Prof. S.Vaidyanathan, Head of the

Department, Department of Electronics & Communication Engineering for their timely

assistance during the course of this seminar.

I would like to thank our institution and our faculty members without whom

this seminar would have been a distant reality. I also extend our heartfelt thanks to our

families and well wishers. Last but not the least I would like to express our gratitude to

God almighty.

Vinod V

ABSTRACT

Ultra-wideband (UWB) transmission has recently received great attention in both academia

and industry for applications in wireless communications. It was among the CNN’s top

10 technologies to watch in 2004. A UWB system is defined as any radio system that

has a 10-dB bandwidth larger than 20% of its center frequency, or has a 10-dB band-

width equal to or larger than 500 MHz. The recent approval of UWB technology by

Federal Communications Commission (FCC) of the United States reserves the unlicensed

frequency band between 3.1 and 10.6 GHz (7.5 GHz) for indoor UWB wireless commu-

nication systems. It is expected that many conventional principles and approaches used

for short-range wireless communications will be reevaluated and a new industrial sector

in short-range (e.g., 10 m) wireless communications with high data rate (e.g., 400 Mbps)

will be formed. Further, industrial standards IEEE 802.15.3a (high data rate) and IEEE

802.15.4a (very low data rate) based on UWB technology have been introduced.

CONTENTS

SECTION Page No:

List of TABLES i

1. INTRODUCTION 1

1.1. History and Background 2

1.2. FCC Emission limits 4

1.3. UWB Concepts 6

1.4. UWB Signals 9

2. Why UWB 11

3. Bandpass UWB 18

3.1 Filter Technologies 18

4. Multiband-OFDM Approach 21

5. IR-UWB Vs. MB-OFDM 29

6. LNA Architecture 30

7. UWB Antennas 32

8. UWB Vs. Spread Spectrum 35

9. UWB Applications 37

9.1 UWB Outdoor peer-to-peer network (OPPN) 40

9.2 UWB Radar 41

9.2.1 Measuring method 42

9.2.2 UWB radar over NB radar 45

9.2.3 Position Estimation Techniques 46

9.2.4 UWB radar Detection of people in an open area 49

9.2.5 UWB radar monitoring of the level of a liquid 50

9.2.6 GPR- Ground Penetrating Radar 51

9.2.7 guarding of objects 53

9.2.8 Precision Asset Location (PAL) System 54

9.2.9 Vehicular collision avoidance 55

9.2.10 UWB Radars in Medicine 56

9.2.11 Optical UWB RADAR 61

9.3 HDR WPAN 62

9.4 LDR WSN 64

9.5 LDR WBAN 65

10. UWB Network Extension 66

11. UWB ECG Monitoring 68

12. UWB-MIMO 69

13. UWB Endoscope 71

14. BToUWB 72

15. Wireless USB 73

16. UWB SATCOM 74

17. Related Technologies 75

18. Challenges to UWB 78

19. Conclusion 79

References 80

Appendix- UWB transceiver examples 82

i

LIST OF TABLES

TABLE Page No:

TABLE.1.3 6

TABLE.4 27

TABLE.5 29

TABLE.7 34

TABLE.17 75

TABLE.19 78

UWB- Seminar Report 2010 Dept. Of Electronics & Communication

SCT Engineering College, TVM 1

1. INTRODUCTION

Every radio technology allocates a specific part of the spectrum; for example, the signals

for TVs, radios, cell phones, and so on are sent on different frequencies to avoid

interference to each other. As a result, the constraints on the availability of the

RF spectrum becomes more and more strict with the introduction of new radio services.

Ultra-wideband (UWB) technology offers a promising solution to the RF spectrum

drought by allowing new services to coexist with current radio systems with minimal or no

interference. This coexistence brings the advantage of avoiding the expensive spectrum

licensing fees that providers of all other radio services must pay.

This seminar provides a comprehensive overview of ultra-wideband Communications.



1.1 HISTORY AND BACKGROUND

Ultra-wideband communications is not a new technology; in fact, it was first

employed by Guglielmo Marconi in 1901 to transmit Morse code sequences across the

Atlantic Ocean using spark gap radio transmitters. However, the benefit of a large

bandwidth and the capability of implementing multiuser systems provided by

electromagnetic pulses were never considered at that time. Approximately fifty years after

Marconi, modern pulse-based transmission gained momentum in military applications

in the form of impulse radars. Some of the pioneers of modern UWB communications in the

United States from the late 1960s are Henning Harmuth of Catholic University of America

and Gerald Ross and K. W. Robins of Sperry Rand Corporation .

FIG. 1.1



From the 1960s to the 1990s, this technology was restricted to military and Department of

Defense (DoD) applications under classified programs such as highly secure

communications. However, the recent advancement in microprocessing and fast switching

in semiconductor technology has made UWB ready for commercial applications. Therefore,

it is more appropriate to consider UWB as a new name for a long-existing technology. As

interest in the commercialization of UWB has increased over the past several years,

developers of UWB systems began pressuring the FCC to approve UWB for commercial use.

In February 2002, the FCC approved the First Report and Order (R&O) for commercial

use of UWB technology under strict power emission limits for various devices.



1.2 FCC EMISSION LIMITS

In order to protect existing radio services from UWB interference, the FCC has

assigned conservative emission masks between 3.1 GHz and 10.6 GHz for commercial

UWB devices. The maximum allowed power spectral density for these devices—that is,

–41.3 dBm/MHz, or 75 nW/MHz—places them at the same level as un-intentional

radiators (FCC Part 15 class) such as televisions and computer monitors.

FIG. 1.2



The spectral mask for outdoor devices is 10 dB lower than that for indoor devices,

between 1.61 GHz and 3.1 GHz, as shown in above Figure.

According to FCC regulations, indoor UWB devices must consist of handheld equipment,

and their activities should be restricted to peer-to-peer operations inside buildings.

The FCC’s rule dictates that no fixed infrastructure can be used for UWB communications

in outdoor environments. Therefore, outdoor UWB communications are restricted to

handheld devices that can send information only to their associated receivers.



1.3 UWB CONCEPTS

Narrow band, Wide band, UWB

FIG. 1.3

TABLE.1.3



Traditional narrowband communications systems modulate continuous waveform (CW)

RF signals with a specific carrier frequency to transmit and receive information.

A continuous waveform has a well-defined signal energy in a narrow frequency band that

makes it very vulnerable to detection and interception. Above Figure represents both

narrowband & wideband signals in the time and frequency domains.

UWB systems use carrierless, short-duration (picosecond to nanosecond) pulses with a

very low duty cycle (less than 0.5 percent) for transmission and reception of the

information.

Low duty cycle offers a very low average transmission power in UWB

communications systems. The average transmission power of a UWB system is on the

order of microwatts, which is a thousand times less than the transmission power of a cell-

phone! However, the peak or instantaneous power of individual UWB pulses can be

relatively large, but because they are transmitted for only a very short time, the aver-

age power becomes considerably lower. Consequently, UWB devices require low transmit

power due to this control over the duty cycle, which directly translates to longer battery

life for handheld equipment. Since frequency is inversely related to time, the



short-duration UWB pulses spread their energy across a wide range of frequencies—

from near DC several gigahertz (GHz)—with very low power spectral density (PSD).

The wide instantaneous bandwidth results from the time-scaling property of theoretical

Fourier transforms.



1.4 UWB SIGNALS

UWB modulates an impulse-like waveform (WAVELET) with Data. A typical baseband UWB

pulse, also called monopulse, such as the Gaussian first derivative pulse can be used.

UWB signals must have bandwidths of greater than 500 MHz or a fractional bandwidth

larger than 20 percent at all times of transmission. Fractional (relative) bandwidth is a

factor used to classify signals as narrowband, wideband, or ultra-wideband and is defined

by the ratio of bandwidth at –10 dB points to center frequency.

FIG. 1.4(a)



where fh and f1 are the highest and lowest cutoff frequencies (at the –10 dB

point) of a UWB pulse spectrum, respectively. A UWB signal can be any one of a variety of

wideband signals, such as Gaussian, chirp, wavelet, or Hermite-based short-duration

pulses. Above Figure represents a Gaussian monocycle as an example of a UWB pulse.

WAVELET Generation

The development of laser-actuated semiconductor fast-acting switches that can

produce impulses or short duration waveforms of one or several cycles has been of

interest for UWB. The traveling wave tube (TWT) can be used. It can be excited with

a narrow impulse, but its energy is limited by the peak power of the TWT.

FIG. 1.4(b)



2. Why UWB?

The nature of the short-duration pulses used in UWB technology offers several

advantages over narrowband communications systems. Next, we discuss some of the key

benefits that UWB brings to wireless communications.

2.1 Ability to share the Frequency Spectrum

UWB systems reside below the noise floor of a typical narrow-band receiver and

enables UWB signals to coexist with current radio services with minimal or no interference.

FIG. 2.1



2.2 Large Channel Capacity

One of the major advantages of the large bandwidth for UWB pulses is improved

channel capacity. Channel capacity, or data rate, is defined as the maximum amount of

data that can be transmitted per second over a communications channel. The large channel

capacity of UWB communications systems is evident from Hartley-Shannon’s capacity

formula shown above. Where C represents the maximum channel capacity,

B is the bandwidth, and SNR is the signal-to-noise power ratio. As shown in Equation,

channel capacity C linearly increases with bandwidth B. Therefore, having several

gigahertz of bandwidth available for UWB signals, a data rate of gigabits per second

(Gbps) can be expected.

However, due to the FCC’s current power limitation on UWB transmissions, such a

high data rate is available only for short ranges, up to 10 meters. This makes UWB systems

perfect candidates for short-range, high-data-rate wireless applications such as wireless

personal area networks (WPANs). The trade-off between the range and the data rate



makes UWB technology ideal for a wide array of applications in military, civil, and

commercial sectors.

2.3 Ability to work with Low Signal-to-Noise ratios

The Hartley-Shannon formula for maximum capacity also indicates that the channel

capacity is only logarithmically dependent on signal-to-noise ratio (SNR). Therefore, UWB

communications systems are capable of working in harsh communication channels

with low SNRs and still offer a large channel capacity as a result of their large bandwidth.

2.4 Low probability of intercept and detection

Because of their low average transmission power,UWB communications systems

have an inherent immunity to detection and intercept. With such low transmission power,

the eaves-dropper has to be very close to the transmitter (about 1 meter) to be able

to detect the transmitted information. In addition, UWB pulses are time modulated

with codes unique to each transmitter/receiver pair. The time modulation of extremely

narrow pulses adds more security to UWB transmission, because detecting picosecond



pulses without knowing when they will arrive is next to impossible. Therefore, UWB

systems hold significant promise of achieving highly secure, low probability of inter-

cept and detection (LPI/D) communications that is a critical need for military operations.

2.5 Resistance to Jamming

Processing gain (PG) is a measure of a radio system’s resistance to jamming and is

defined as the ratio of the RF bandwidth to the information bandwidth of a signal. The

frequency diversity caused by high processing gain makes UWB signals relatively resistant

to intentional and unintentional jamming, because no jammer can jam every frequency

in the UWB spectrum at once. Therefore, if some of the frequencies are jammed,

there is still a large range of frequencies that remains untouched. However, this resis-

tance to jamming is only in comparison to narrowband and wideband systems. Hence, the

performance of a UWB communications system can still be degraded, depending on its

modulation scheme, by strong narrow-band interference from traditional radio transmitters

coexisting in the UWB receiver’s frequency band.



2.6 High performance in multipath channels

The phenomenon known as multipath is unavoidable in wireless communications

channels. It is caused by multiple reflections of the transmitted signal from various

surfaces such as buildings, trees, and people. The straight line between a transmitter

and a receiver is the line of sight (LOS); the reflected signals from surfaces are

non-line of sight (NLOS).

The effect of multipath is rather severe for narrowband signals; it can cause signal

degradation up to –40 dB due to the out-of-phase addition of LOS and NLOS continuous

waveforms. On the other hand, the very short duration of UWB pulses makes them less

sensitive to the multipath effect. Because the transmission duration of a UWB pulse is

shorter than a nanosecond in most cases, the reflected pulse has an extremely short

window of opportunity to collide with the LOS pulse and cause signal degradation.



2.7 Superior penetration properties

Unlike narrowband technology, UWB systems can penetrate effectively

through different materials. The low frequencies included in the broad range of the UWB

frequency spectrum have long wavelengths, which allows UWB signals to penetrate a

variety of materials, including walls. This property makes UWB technology viable for

through-the-wall communications and ground-penetrating radars (GPRs). However, the

material penetration capability of UWB signals is useful only when they are allowed to

occupy the low-frequency portion of the radio spectrum.

2.8 Simple transceiver architecture

UWB transmission is carrierless, meaning that data is not modulated on a continous

waveform with a specific carrier frequency, as in narrowband and wideband technologies.

Carrierless transmission requires fewer RF components than carrier-based transmission.

For this reason UWB transceiver architecture is significantly simpler and thus cheaper

to build.



The transmission of low-powered pulses eliminates the need for a power amplifier

(PA) in UWB transmitters. Also, because UWB transmission is carrier-less, there is no

need for mixers and local oscillators to translate the carrier frequency to the required

frequency band; consequently there is no need for a carrier recovery stage at the

receiver end. In general, the analog front end of a UWB transceiver is noticeably less

complicated than that of a narrowband transceiver. This simplicity makes an all-CMOS

implementation of UWB transceivers possible, which translates to smaller form

factors and lower production costs.

FIG. 2.8



3. Bandpas UWB

Low energy, short duration UWB pulses modulates Input data.Microwave Spectrum

controlled by BPF impulse response. Modulation scheme may be among PPM, OOK, or

BPSK.

3.1 Filter Technologies

UWB bandpass filter is a key component of UWB system. It must have an ultra wide

passband, but also needs high selectivity to reject signals from existing systems such as

1.6 GHz global positioning systems (GPS) and 2.4 GHz Blu-etooth systems. In addition, in

some cases, the UWB bandpass filter needs to introduce steeply notched frequency bands

FIG. 3



in order to reduce interference from existing NB radio systems located within the UWB

pass-band. These requirements increase the challenges for the UWB filter designer.

However, since conventional filter theory is based on the narrowband assumption and

cannot be used to design UWB bandpass filters , novel techniques and technologies need

to be developed for UWB bandpass filter design.

FIG. 3.1(a)



Microstrip Filter

microstrip filters ony become practical above 300MHz. It is a size issue. the inductance and

capacitance of the the microstrip line PCB traces to form the filter, rather then discrete

inductors and capacitors.

FIG. 3.1(b)

FIG. 3.1(c)



4. Multiband-OFDM Approach

The ability of UWB technology to provide very high data rates for short

ranges (less than 10 meters) has made it an excellent candidate for the physical layer of

the IEEE 802.15.3a standard for wireless personal area networks (WPANs). However, two

opposing groups of UWB developers are battling over the IEEE standard. The two

competing technologies are single band and multiband. The single-band technique,

backed by Motorola/XtremeSpectrum, supports the idea of impulse radio that is the

original approach to UWB by using narrow pulses that occupy a large portion of the

spectrum. The multiband approach divides the available UWB frequency spectrum

(3.1 GHz to 10.6 GHz) into multiple smaller and nonoverlapping bands with bandwidths

greater than 500 MHz to obey the FCC’s definition of UWB signals. The multiband

approach is supported by several companies, including Staccato Communications,

Intel, Texas Instruments, General Atomics, and Time Domain Corporation.

To date, several proposals from both groups have been submitted to the

IEEE 802.15.3a working group, and the decision is yet to be made because



both technologies are impressive and have technical credibility. The following subsections

discuss the two leading candidates for the 802.15.3a standard: direct-sequence UWB

(DS-UWB) and multiband orthogonal frequency division multiplexing (OFDM)

DIRECT-SEQUENCE UWB

Above figure shows DS-UWB with 3.1-to 5-GHz range band plan.

FIG. 4(a)



And the below figure shows DS-UWB with 6-to 10.6-GHz band plan

Direct-sequence UWB is a single-band approach that uses narrow UWB pulses and

time-domain signal processing combined with well-understood DSSS techniques to

transmit and receive information. Data representation in this approach is based on

simple bi-phase shift keying (BPSK) modulation, and rake receivers are used to

capture the signal energy from multiple paths in a multipath channel.

FIG. 4(b)



According to the proposals sent to the IEEE 802.15.3a standardization committee by

the proponents of this technology, the DS-UWB technique is scalable and can achieve

data rates in excess of 1 Gbps. The technical reason behind using DS-UWB is the

propagation benefits of ultra-wideband pulses, which experience no Rayleigh fading. In

contrast, narrowband transmissions degrade significantly due to fading.

MULTIBAND OFDM

FIG. 4(c)



The multiband UWB approach uses the 7500 MHz of the RF spectrum

available to UWB communications in a way that differs from traditional UWB techniques.

The UWB frequency band is divided into multiple smaller bands with bandwidths greater

than 500 MHz.

This approach is similar to the narrowband frequency-hopping technique.

Dividing the UWB spectrum into multiple frequency bands offers the advantage of avoiding

transmission over certain bands, such as 802.11a at 5 GHz, to prevent potential

interference. In the multiband approach, UWB pulses are not as narrow as in traditional

UWB techniques; therefore, synchronization requirements are more relaxed. A variety of

modulation techniques have been proposed by industry leaders for the multiband

approach; however, OFDM, which was initially proposed by Texas Instruments, offers

improved performance for high-data-rate applications. Infact, both technologies are

technically valid and impressive. Supporters of DS-UWB criticize the multiband OFDM

systems for their complexity, which results from using complex Fast Fourier Trans-

forms (FFTs). On the other side, advocates of multiband OFDM believe that their technique

offers better coexistence with other radio services, and they disapprove of DS-UWB



because of possible interference concerns. The debate will likely continue until the IEEE

802.15.3a standardization committee reaches a decision.

MB-OFDM generation method

PLL provides center frequencies for first three Group “A” bands.

FIG. 4(d)



Integration of Multiband and cognitive radio (CR)

Cognitive Radio(CR) is an emerging approach for a more flexible usage of the precious radio

spectrum resources. By investigations on the radio spectrum usage, it has been observed

that some frequency bands are largely unoccupied most of the time, some other frequency

TABLE.4

FIG. 4(e)



bands are only partially occupied, and the remaining frequency bands are heavily used.

A CR terminal can sense its environment and location and then adapt some of its features

allowing to dynamically reuse valuable spectrum. This could lead to a multidimensional

reuse (dynamical usage) of spectrum in space, frequency and time, exceeding the severe

limitations in the spectrum and bandwidth allocations.



5. IR-UWB Vs. MB-OFDM

TABLE.5



6. LNA architecture

Due to the wide bandwidth, classical narrow band LNA design techniques cannot be used.

Feedback amplifier architecture, described in Figure, has been considered as a good

candidate for wideband amplification due to its relative simplicity to provide flat gain and

good 50 Ohms matching with respect to low noise.

Wideband input impedance matching

The main challenge in UWB designs is to extend matching to the wide frequency range of

3.1-10.6 GHz. The LNA has to exhibit good input impedance.

FIG. 6(a)



NB Interference suppression

A tunable center frequency RF “roofing filter” applied to the UWB NB interference

mitigation problem. This filter will introduce significant group delay distortion in the

passband, and so spectral shaping of the transmitted waveform out of the interference

band will also be required to minimize the resulting degradation in system performance.

In the second case, an accurate estimation of the frequency, phase, and amplitude of the

jammer is required to significantly reduce the interference level.

FIG. 6(b)

FIG. 6(c)



7. UWB Antennas

Antennas are particularly challenging aspect of UWB. If an impulse is fed to an antenna,

it tends to ring, severely distorting the pulse and spreading it out in time. Poor matching

and large reflections. Conventional wideband antennas such as the log-periodic and

the spiral are wideband in amplitude, but not in phase; they distort the UWB signal.

The best antennas for UWB are arrays of TEM horns. The higher the frequency the antennas

can be equally small.

In UWB systems, antenna design is one of key technologies and has been widely

investigated by both academia and industry. The antenna design considerations are

strongly dependent on the modulation scheme, which the UWB systems are using, and

applications.



In general, MB-OFDM UWB wireless communication systems require the antennas which

should have broadband response in terms of return loss, gain at the directions of

interest, and /or polarization. Such requirements are almost the same as the designs for

conventional broadband wireless systems but a required extremely broad bandwidth of

50% to 100% with a consistent gain response.

However, additional attention must be paid for pulse-based UWB systems where the UWB

antenna usually function as a bandpass filter and tailor the spectra of the radiated/

received pulses so that the waveforms of radiated/received pulses are distorted.



TABLE.7

FIG. 7



8. UWB Vs. SPREAD SPECTRUM

Although UWB and spread-spectrum techniques share the same advantage

of expanded bandwidth, the method of achieving the large bandwidth is the main

distinction between the two technologies. In conventional spread-spectrum techniques,

the signals are continuous-wave sinusoids that are modulated with a fixed carrier

frequency.

FIG. 8



In UWB communications, on the other hand, there is no carrier frequency; the short

duration of UWB pulses directly generates an extremely wide bandwidth. Another

distinguishing factor in UWB is the very large bandwidth. Spread-spectrum techniques can

offer megahertz of bandwidth, while UWB pulses provide several gigahertz of bandwidth.

Above figure shows the time and frequency domain representation of narrowband,

wideband, and UWB signals.

The low transmission power could be a disadvantage for UWB systems, because the

information can travel only short distances. Therefore, for long-range applications, spread-

spectrum techniques are still more appropriate.



9. UWB APPLICATIONS

The trade-off between data rate and range in UWB systems holds great

promise for a wide variety of applications in military, civilian, and commercial sectors.

The FCC categorizes UWB applications as either radar, imaging, or communications devices.

Radar is considered one of the most powerful applications of UWB technology. The

fine positioning characteristics of narrow UWB pulses enables them to offer high-resolution

radar (within centimeters) for military and civilian applications. Also, because of the very

wide frequency spectrum band, UWB signals can easily penetrate various obstacles. This

property makes UWB-based ground-penetrating radar (GPR) a useful asset for rescue

and disaster recovery teams for detecting survivors buried under rubble

in disaster situations.

In the commercial sector, such radar systems can be used on construction

sites to locate pipes, studs, and electrical wiring. The same technology under different

regulations can be used for various types of medical imaging, such as remote heart

monitoring systems. In addition, UWB radar is used in the automotive industry for collision



avoidance systems. Moreover, the low transmission power of UWB pulses makes them

ideal candidates for covert military communications. UWB pulses are extremely difficult to

detect or intercept; therefore, unauthorized parties will not get access to secure military

information. Also, because UWB devices have simpler transceiver circuitry than

narrowband transceivers, they can be manufactured in small sizes at a lower price than

narrowband systems.

Small and inexpensive UWB transceivers are excellent candidates for

wireless sensor network applications for both military and civilian use. Such sensor

networks are used to detect a physical phenomenon in an inaccessible area and transfer

the information to a destination. A military application could be the detection of biological

agents or enemy tracking on the battlefield. Civilian applications might include habitat

monitoring, environment observation, health monitoring, and home automation.

The precise location-finding ability of UWB systems can be used in inventory

control and asset management applications, such as tagging and identification systems—

for example, RFID tags. Also, the good performance of UWB devices in multipath channels



can provide accurate geolocation capability for indoor and obscured environments where

GPS receivers won’t work.

The high-data-rate capability of UWB systems for short distances has

numerous applications for home networking and multimedia-rich communications in the

form of WPAN applications. UWB systems could replace cables connecting camcorders and

VCRs, as well as other consumer electronics applications, such as laptops, DVDs, digital

cameras, and portable HDTV monitors. No other available wireless technologies—

such as Bluetooth or 802.11a/b—are capable of transferring streaming video.



9.1 UWB Outdoor peer-to-peer network (OPPN)

Downloading of video movie purchase or rental, for example, is a very data-intensive

activity that could be enabled by UWB.

FIG. 9.1



9.2 UWB radar (Short-range radar (SRR))

The wide bandwidth of UWB signals implies a fine time resolution that gives them a

potential for high-resolution positioning applications /Localization and tracking (LT)/

ranging, provided that the multipaths are dealt with.

As of Short Pulse Width we can Resolve Multipath Components .

FIG. 9.2



Above Figure demonstrates external views of this UWB radar model.

The major specifications of the prototype are given be

• Operation range 8 m;

• Pulse power 10 mW;

• Average power 80 ~W;

• Width of the antenna 's pattern: 8° x 8°; and

• Duration of radiated radio pulses 2 ns.

9.2.1 THE MEASURING METHOD OF UWB RADAR

While constructing UWB radars, as with constructing conventional narrow-band radars,

we use the property of electromagnetic waves to be scattered from a boundary of

two media with different parameters. The short electromagnetic pulses radiated by radar

are scattered by a moving object. The oscillation frequency within the pulse and the

repetition frequency ofpulses are changed owing to the Doppler effect. The sign of these

variations depends on the direction of target movement relative to the radar and the

variation value depends on the object's radial velocity. According to this direction, the signal

spectrum is going wider or narrower and moves toward high or low frequency areas.



The radars work in conditions of high level of passive noise - the signals, reflected from

walls and stationary objects, which will have large amplitude and will disguise useful signals.

Time slots, opening the receiver at the moment of input of signal reflected from object at

distance defined are formed in receiving path to eliminate interfering pulses. This task in

radar design is executed by a time discriminator, being gated. It consists of fast-acting

electronic switches. The switching time is on the order of 200-300 picoseconds. The

switches connect the receiving antenna to the UWB amplifier at the moment of signal input.

These moments are defined by a delay magnitude of the control signal at a software-

controlled delay line. All of the rest of the time, the receiver is closed. The signals received

at time slots are detected and amplified in integrating amplifier and the signal, carrying

data of target motion is selected at its output.

The time constant of integration of integrating amplifier is chosen independently of the

bandwidth of the desired signal. For example, measuring a person's vital signs, the

bandwidth of the desired signal is near 40 - 50 Hz, that corresponds to an accumulation of



10 - 30 thousands of pulses, approximately. The accumulation permits us to decrease the

average radiated power of the transmitter and increase the signal-to-noise ratio at the

input of the amplifier.

The selected and amplified low-frequency signal enters the analog-digital converter (ADC) .

The microprocessor-controlled unit directs the work of the radar on given algorithms,

monitors the state of major units and modules, and provides data output for further digital

processing in the computer. The selection of moving targets, fast Fourier transform, and

digital filtration are software-programmable at the computer.



9.2.2 UWB radar over NB radar

• Higher range resolution and accuracy .Ultra High Range Resolution (UHRR)

• enhanced target recognition

• immunity to passive “interference”

• immunity to co-located radar transmissions

• signals scattered by separate target elements do not interfere

• operational security because of the extremely large spectral spreading

• ability to detect very slowly moving or stationary targets

• Multiple targets can be resolved

• With a long pulse NB radar waveform, changes in the target aspect cause a

change only in the amplitude of the echo signal. With UWB signals, the echo

signal will change, which makes efficient signal processing.

• NB signal processing in radar almost always utilizes the envelope. With UWB

waveforms, either the envelope or the RF signal can be used.

• In indoor and dense urban environments the GPS signal is typically unavailable.



9.2.3 POSITION ESTIMATION TECHNIQUES

FIG. 9.2.3(a)



In the below set-up Short-pulse RF emissions from the tags are subsequently received by

either all, or a subset, of these sensors and processed by the central hub CPU.

A set of three or more receivers (four receivers are typically used) are positioned at

known coordinates within, or about the periphery of, the area to be monitored.

FIG. 9.2.3(b)



In order to comprehend the high-precision positioning capability of UWB signals,

position estimation techniques should be investigated first. Position estimation of a node

in a wireless network involves signal exchanges between that node

(called the target_ node; i.e., the node to be located) and a number of reference nodes.

A central unit that gathers position information from the reference nodes and then

estimates the position based on those signal parameters. Signal parameters, such as

TOA (time-of-arrival), angle-of-arrival (AOA), TDOA (Time Difference of Arrival),

RTD (Round Trip Delay) and/or received signal strength (RSS), are estimated.

Short-pulse RF emissions from the tags are subsequently received by receivers and

processed by the central hub CPU. A typical tag emission consists of a short burst, which

includes synchronization preamble, tag identification (ID), optional data field (e.g., tag

battery indicator), and FEC bits. Time differences of arrival (TDOA) of the tag burst at the

various receiver sites are measured and sent back to the central processing hub for

processing. Calibration is performed at system startup by monitoring data from a reference

tag, which has been placed at a known location.



9.2.4 UWB radar Detection of people in an open area

Detection was made on two persons moving a distance 50 meters from the edge of a forest.

The results of measurements are shown in below waveform.

FIG. 9.2.4(a)

FIG. 9.2.4(b)



9.2.5 UWB radar monitoring of the level of a liquid

This radar provides measurements of a liquid's level in tankage which can have a depth

from I to 20 meters. Accuracy of measurements is 5mm. The radar transfers the data of

measurements via wireless communication line to a control panel with a rate of 5c.

FIG. 9.2.5



9.2.6 GPR- Ground Penetrating Radar

(Through-wall detection UWB radar)

Radar cross section (RCS) - An example of total propagation losses and reflection losses in a

simplified through-wall detection scenario

Here strongest clutter signal occurs by reflection from a wall and the weakest expected

reflection from a target at the maximal range. As key functional requirements to the radar

we select the separation of a breathing target from a stationary clutter.

FIG. 9.2.6(a)

FIG. 9.2.6(b)



SPIDER

GPR was deployed as a backup sensor for a large mining vehicle.

GPR system block diagram

FIG. 9.2.6(c)

FIG. 9.2.6(d)



9.2.7 guarding of objects

QUick response Perimeter Intrusion Detection –QUPID

The UWB radar is also used for guarding of objects in the medicine storage room.

The UWB electromagnetic wave is just like defense sphere detecting any moving objects

crossing the guarded perimeter line. Fig. demonstrates the scheme of guarding of objects.

Waveform shows output radar signals which fluctuate corresponding to something

crossing of the secured perimeter line. Thus can be used to protect a perimeter from

unauthorized intruders.

FIG. 9.2.7



9.2.8 Precision Asset Location (PAL) System

For detection of on-board items inside vehicles

In an automotive environment, the localization of a wireless key, inside or

outside a car and its distance from the car, could be estimated by UWB radar technique.

FIG. 9.2.8



9.2.9 Vehicular collision avoidance

In this application, an approaching car is detected by using SRR as well as delivery of

warning messages by wireless communication from the approaching car.

Smart highways- UWB devices placed inside the vehicles enable them to communicate and,

thus, provide real time local intelligence in order to avoid accidents.

The 2006 Mercedes S-Class uses 24 GHz short range UWB radar as part of its driver assistant

systems. Elapsed time of pulsed signals is used to detect objects within 0.2 to 30 m. It can

detect and track up to 10 objects with a range accuracy of 7.5 cm.

FIG. 9.2.9



9.2.10 UWB Radars in Medicine

Discrete pulses emitted from the UWB transmitter travel to the human body and incidence

it. The pulses comprising the information reflected from the human body travel back to the

UWB receiver and then the result is recorded. Signal processing is performed through

obtaining the pulses response with the shape and electrical properties of pulse.

Electromagnetic pulses coming from a UWB radar are able to probe the human body.

A UWB radar was able to detect, non-invasively, the movements of the heart wall.

This is because there exists a definite difference in reflection magnitude between the

heart muscle and the blood it pushes into the vascular tree.

This evidence opens up a whole new area for non-invasive measures and monitoring of

human body functions. In practice, any object of adequate size can be monitored. Vocal

FIG. 9.2.10(a)



cords, vessels, bowels, heart, lung, chest, bladder and fetus are good candidates for UWB

radar probing. Radar monitoring of human physiologic functions was considered as

early as the 1970s , but any further development was impeded by the cumbersome and

expensive technology of those times.

As long as human body monitoring is concerned, it has to be recognized that no other

technology is using the same physical principle as UWBs. Further, no other system or

methodology lets one monitor the movements of internal organs without direct skin

contact or using a radiated, instead of induced electromagnetic field. Functional

magnetic resonance imaging (fMRI) is actually providing images of moving internal organ

but, as it uses an induced field, the patient has to be confined UWB radar, using a radiated

field, lets the patient be absolutely free in space. No other direct comparison is to be

made between UWB radar and MRI, as the purpose and final clinical target of the two

methodologies are far too different.

AS the UWB electromagnetic signal is not influenced by clothes or blankets, and the

useful range is in the order of a few meters, a through-clothing heart rate monitor is

viable so that interesting potential applications can be envisioned. Home



health care, emergency rooms, intensive care units, hospitals, pediatric clinics (to alert

for the Sudden Infant Death Syndrome, SIDS), rescue operations (to look for some

heart beating under ruins, or soil, or snow) or law enforcement are some potential areas

of application.

UWB pulse-echo delay times in the human body

UWB Radar emits (W tc) a short packet of electromagnetic waves whose echoes (W

echo) are sampled using “conventional” UWB receiver.

FIG. 9.2.10(b)



A straightforward application of UWB radar-based heart and breath activities

is shown for intensive care units (IU) and conventional hospital beds as well

UWB radar-based exploration of arteries

A UWB radar could replace presently used fetal monitors which use ultrasound (to detect

placentary blood flow) and pressure sensors (to detect uterine contractions): the UWB

FIG. 9.2.10(c)

FIG. 9.2.10(d)



radar signal contains data about maternal heart rate, maternal breath rate, fetal heart rate,

fetal movements, and uterine contractions. Furthermore the remote, non-contact,

non-invasive operation permits conventional, uninterrupted mother and child care.

UWB radar emissions are safe and, therefore, the system is well suited for a

chronically positioned equipment to monitor the last period of pregnancy.

FIG. 9.2.10(e)



9.2.11 OPTICAL UWB RADAR

Instead of emitting a short electromagnetic pulse, a short train-wave of light

(Electromagnetic energy as well) is emitted (IR laser diode is used as the antenna) and the

echoes detected by a very fast PIN photodiode (UWB receiver equipped with a PIN

Photodiode). Resulting biomedical applications are quite interesting.



9.3 High Data Rate(HDR) WPAN (IEEE 802.15.3a)

AWICS (Aircraft Inter communications system), is specifically designed for use in extremely

high multipath environments such as those commonly encountered inside helicopters and

aircraft. As such, its audio data rate and packet structure was selected to permit operation

in the presence of severe signal reverberation.

However, with spread spectrum, multipath signal degradation was prevalent within

the confines of the aircraft fuselage. Deleterious multipath effects were also encountered in

communications between an internal base unit and a remote user standing outside of the

aircraft while the rotor system was engaged and turning. In the latter case, the degradation

was found to be caused by multipath

FIG. 9.3



reflections from the large rotor system. The receiver essentially encountered a

self-jamming situation from its own signal reflections. After an initial exploration of

spread-spectrum signaling, UWB eventually emerged as a leading candidate technology

for AWICS applications.

As shown, both pilot and copilot remain tethered, whereas crewmen are permitted to be

mobile. UWB AWICS support eight simultaneously transmitting (i.e., “party line”) mobile

users.

The AWICS system operates at -band with an instantaneous 3-dB RF bandwidth of

approximately 400 MHz and an effective isotropic radiated power (EIRP) of approximately

26 dBm.



9.4 Sensor, positioning, and identification network (SPIN)

LDR WSN (IEEE 802.15.4a) for precision automobile parking

To identify whether a particular slot in parking area has been occupied. Sensors produce

LDR pulses to indicate slot occupancy. Pulses are guided to Master AP at security cabin,

through Slave APs. Master AP will display exact vacant slot, thus security person can guide

the incoming vehicles to the correct direction.

FIG. 9.4



9.5 Wearable LDR WBAN (IEEE 802.15.6)

Wearable WBAN for telemedicine

The sensing devices are connected to a central node that is able to transmit data over the

wider area network to alert the physician.

FIG. 9.5



10. UWB NETWORK EXTENSION

The network is extended to cover wider area. IEEE 1394 can operate over both copper

and fiber single cable. IEEE 1394 is an international standard for high performance serial

bus that will enable simple, low-cost, and high-bandwidth isochronous/asynchronous data

interfacing between UWB buses.

The convergence of UWB and optical fiber distribution techniques, or UWB over fiber

(UROOF), offers the availability of undisrupted service across different networks and

eventually achieves high-data-rate access at any time and from any place. UWB pulses are

generated and encoded in the central office (CO) and distributed to the access points (APs)

via the optical fiber.

FIG. 10(a)



UROOF

(UWB Radio Over Optical Fiber) for broadband indoor wireless access

Another technique for UWB Network extension

To recover the information that is carried by the optical phase, we have to convert

a phase-modulated signal to an intensity-modulated signal (PM-IM). A dispersive

Device (single-mode fiber (SMF)) is used to change the phase relationship between the two

first-order sidebands from out of phase to partially or fully in phase. The electrical signal is

obtained at the output of a PD, which is ready to radiate to the space via an UWB antenna.

FIG. 10(b)

FIG. 10(c)



11. LDR UWB ECG Monitoring System

UWB in Biotelemetry

THE emergence of low power and robust wireless biotelemetry devices has increased

patient mobility and the efficiency of medical staff. Monitoring vital signs for patients

that require long term care can now be performed remotely in the patient’s comfort,

allowing medical staff to monitor several patients simultaneously. UWB is one of the

potential candidates for the body area network.

ECG signals recovered

FIG. 11(a)

FIG. 11(b)



12. UWB-MIMO

MIMO (multiple-input multiple Output) techniques provide better spatial diversity and

higher system capacity. With the development of mobile communication, MIMO

techniques will be widely applied into B3G or 4G mobile communications in the future.

But, most of mobile terminals（MTs）still utilize single antenna/antenna arrays, so the

advantages of MIMO systems can’t be fully exhibited.To exhibit MIMO, MT with multiple-

antenna needed.For that, UWB-based Virtual-MIMO system for cellular network is

proposed. Each AP has a total 9 antennas/antenna arrays and servers the same area of 9

FIG. 12



traditional cells. There are 3 Group Cells connected with AP1, which are GT1 consisting of

MT1 and MT2 antenna arrays connect with each other by UWB GT2 consisting of MT3 and

MT4 one or multiple antennas connect with each other by UWB GT3 consisting of MT5 and

MT6 hybrid antennas composed by antennas/antenna arrays connect with each other by

UWB One MT can directly communicate with some other MTs nearby without AP’s relaying.

Each MT in GT is able to not only directly communicate with AP, but also connect with AP

by sharing the antennas of other MTs in the same GT. Ultra-wide-band (UWB) technology

combined with multiple transmit and receive antennas (MIMO) is a viable way to achieve

data rates of more than 1 Gb/s for wireless communications. MIMO systems allow for a

substantial increase of spectral efficiency by exploiting the inherent array gain and spatial

multiplexing gain of the systems. It is shown that the spectral efficiency is increased

logarithmically and linearly, respectively, for single transmit and multiple receive antennas

(SIMO) and MIMO systems. For multiple transmit and single receive antenna (MISO)

systems, a threshold for the data transmission rate exists such that the spatial multiplexing

gain can be obtained if the data rate is lower than this threshold. Two STC

(Space Time Coding) schemes for UWB-MIMO are 1S/2A and 2S/2A.



13. UWB Endoscope

Endoscope means real-time diagnosis with high resolution images.

A wireless endoscope system is comprised of a capsule endoscope for image capturing, an

external unit for data recording, analysis and diagnosis of syndrome in the gastrointestinal

tract. The capsule endoscope is compose of a miniaturized camera, light-emitting diodes,

CMOS imager, system controller, radio transceiver and battery. And implemented in

0.18µm digital CMOS. High data transmission afforded by UWB.

FIG. 13



14. Bluetooth over Ultra Wideband (BToUWB)

BToUWB is modeled by channeling an existing compliant Bluetooth connection’s data over

a software implemented UWB Medium Access Control (MAC) and simulated Physical (PHY)

layer radio channel. The simulated UWB link may closely resemble a real life UWB

connection. Utilizing the UWB physical layer may provide even more advantages in terms of

connection setup speed and device power saving.

FIG. 14



15. Wireless USB

Under the WiMedia umbrella, industry incorporated UWB as the technology to achieve high

data rates up to 480 Mbps for Wireless USB. Affordable commercial UWB hardware has

become readily available in the form of WUSB dongles as of 2011. It will replace the USB

cable by providing secure high speed, short range communications, like USB but without the

cables.

Belkin CableFree USB

Certified Wireless USB

FIG. 15



16. UWB SATCOM

The UWB signals can be overlaid on the existing narrowband spectrum. This is expected to

contribute to increasing spectrum efficiency of the satellite systems.

UWB signals for Ku-band downlink with 500 MHz bandwidth. UWB signals are radiated

from satellites to the earth by which new satellite applications can be developed.



17. RELATED TECHNOLOGIES

TABLE.17



It is clear from the figure that UWB is far superior in terms of spatial capacity (bits/sec/sq.

meter) because of larger available bandwidth.

FIG. 17(a)

FIG. 17(b)



Normalized energy consumption for each protocol

FIG. 17(c)

FIG. 17(d)



18. CHALLENGES TO UWB

► suspicious about the NB interference

► extreme antenna bandwidth requirements

► very accurate timing synchronization need for correlator -based receiver

► Cplx RAKE-type receiver to cope with significant amount of energy in the multipath

► filter matching accuracy

► timely approval from the regulatory bodies

► lack of an universal standard

Systems Possibly Degraded by Ultra

Wideband

TABLE.19



19. CONCLUSION

With the recent advances in semiconductor device technology and the

FCC’s approval of the unlicensed use of ultra-wideband systems, UWB development has

moved from research labs and classified military projects to the commercial sector. UWB

technology brings many opportunities as well as challenges to the world of wireless

communications. UWB is a promising technology for the Next Generation Wireless

Systems!

Home audio systems and PCs without the confusing and messy cables and even more

tech savvy cell phones are the promise of UWB. Some people question whether UWB really

will impact consumer life. A better question is when? There is a definite demand for the

applications that can be developed using UWB. UWB also has a unique edge over

competing technologies in its low cost and low power model. Unfortunately early

regulatory division has split UWB implementers down the middle. Countries around the

world have been reluctant to release radio spectrum for UWB use. The consequential lack

of an universal standard must be addressed so consumers can reap the benefits of UWB.



REFERENCES



Ø UWB Systems for Wireless Sensor Networks- Zhang, Sahinoglu- IEEE Proceedings

Ø Why UWB? A Review of Ultra wideband Technology- Miller – DARPA

Ø Semiconductor Technology Choices for UWB Systems- Harame- IEEE

Ø UWB Radars in Medicine -Staderini -IEEE AESS Systems Magazine

Ø Photonic Generation of UWB Signals- Yao-Journal of Lightwave Technology

Ø UWB Localization Techniques for Precision Automobile Parking System –Mary-IEEE

Ø UWB Communications Systems :An Overview- Tommy- IEEE

Ø Overview of Research and Development Activities in NICT UWB Consortium- Kohno

Ø Comparative Evaluation of Different Modulation Schemes in UWB - Sharda Mungale

Ø An introduction to UWB communication systems- Rakesh- IEEE

Ø UWB Filter technologies- Hao-IEEE Microwave magazine

Ø Recent System Applications of Short-Pulse UWB Technology-Fontana

Ø Performance of Coherent and Non-coherent Receivers of UWB Communication-IEEE

Ø Practical Applications of UWB Technology- Immoreev- IEEE A&E Systems Magazine

Ø Introduction to Ultra-Wideband Communications- Nekoogar

Ø Essentials of UWB- Wood, Aiello- Cambridge

Ø UWB Radio technology- Siwiak- Wiley

Ø http://www.timedomain.com/

Ø http://mtlweb.mit.edu/researchgroups/icsystems/uwb/



Appendix



UWB TRANSCEIVER EXAMPLES

• DRACO UWB Network Transceiver

A DRACO transceiver node can be operated as an unattended communications relay,

originating sensor (e.g., video, seismic, acoustic, etc.) communications node, reach back

satellite packet node, or destination terminal. DRACO is a proof-of-concept high-speed

multichannel UWB network incorporating both communications security (COMSEC) and

transmission security (TRANSEC) capabilities. COMSEC is achieved through the use of

Type-1 encryption, while TRANSEC is accomplished through the use of UWB waveform.

DRACO UWB electronics include a VHF/UHF multichannel UWB transmitter, companion

multichannel UWB Receiver, and digital processor.

FIG. 18(a)



• ORIONUWB Network and Ground Wave Non-LOS Transceiver

ORION, was designed for small infantry and platoon operations with both a short-range

(1 km) and long-range (50–60 km) back-haul capability. ORION was designed to be modular

in construction and consists of a motherboard and three plug-in daughter cards

including UWB transmitter and transmit/receive (T/R) module, UWB receiver module, and

digital processor module. The modular architecture was selected to permit ORION

operation in several different frequency bands. The ORION digital processor module is also

implemented in a single FPGA and performs a number of tasks including clock and timing

recovery, RF gain control (AGC), RS-232 data generation and recovery, FEC encoding and

de-coding, burst interleaving and randomization, etc.

FIG. 18(b)

ultra wide band radio technology (uwb)(b-tech seminar report)

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