ULTRA WIDE BAND By JALAL ABD ALI

Title and Content• What is UWB?

• Principles of UWB

• Advantages of UWB

• Applications of UWB

• UWB Characteristics

• Comparison With Other Technologies

• UWB Technologies

• Information Modulation

• Challenges

• Conclusion

• References

What is UWB?

• UWB is a wireless technology developed to transfer data at high rates over very short distances at very low power densities and an area of immense current interest, with Numerous potential applications.

• UWB short-range radio technology complements other longer-range radio technologies such as Wi-Fi, WiMAX, and cellular wide area communications. It is used to relay data from a host device to other devices in the immediate area (up to 10 m or 30 feet).

• Has the ability to carry signals through doors and other obstacles that tend to reflect signals at more limited bandwidths and at higher power levels.

What is UWB? Radio technology that modulates impulse based waveforms instead of

continuous carrier waves

FrequencyModulation

2.4 GHz

Nar

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band

Com

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ion

0 1 0 1

ImpulseModulation

3 10 GHzfrequencyUlt

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ide

band

Co

mm

unic

atio

n Time-domain behavior Frequency-domain behavior

time

1 0 1

(FCC Min=500Mhz)

Principles of UWB

• US FCC defined a UWB signal as any signal with a bandwidth at the

10 dB attenuation points ( 90% spectral power bandwidth) ; Most

narrowband Systems occupy less than 10% of the center frequency

bandwidth, and are transmitted at far greater power levels

greater than 20% of the modulation frequency.

• In Time Domain : very narrow pulses on the order of nanoseconds

(Very low duty cycle )

• In frequency domain :very wide bandwidth in the frequency domain at

at very low power spectral density

Advantages of UWB

• Spectrum Reuse (3.1-10.6 GHz, coexist with other users)• High data rate as hundreds of Mbps or even several Gbps with distances

of 1 to 10 meters• Multipath immunity (Path delay >> pulse width)• Low power {Baseband modulation (no carrier)}• Low cost (Almost “all digital”, simple analog module )• Interference Immunity .UWB systems operate at extremely low power

transmission levels. • High Security

Applications of UWB

Communications - High Speed WLANs, Mobile Ad-Hoc wireless networks, Ground wave Communications, Handheld and Network Radios, Intra-home and Intra-office communication. Stealthy communications provide significant potential for military, law enforcement, and commercial applications.

Sensor Networks - Ground penetrating Radar that detects and identifies targets hidden in foliage, buildings or beneath the ground. Intrusion Detection Radars, Obstacle Avoidance Radars, and Short-range motion sensing.

Tracking/Positioning - Precision Geolocation Systems ( PGS ) and high-resolution imaging. Indoor and outdoor tracking down to less than a centimeter. Good for emergency services, inventory tracking, and asset safety and security.

UWB Characteristics

• Extremely difficult to detect by unintended users• Highly Secured

• Non-interfering to other communication systems• It appears like noise for other systems

• Both Line of Sight and non-Line of Sight operation• Can pass through walls and doors

• High multipath immunity• Common architecture for communications, radar & positioning (software re-

definable)• Low cost, low power, nearly all-digital and single chip architecture

Comparison With Other Technologies• Faster than Bluetooth, Wi Fi• Data rate of 450Mbps instead of 1Mbps• Complementary to existing radio technologies like 802.11

Comparison With Other Technologies

UWB Technologies

• Carrier free direct sequence (DS-UWB)transmits a series of impulses. In view of the very short duration of the pulses, the spectrum of the signal occupies a very wide bandwidth.

• Multi-Band OFDM (MBOFDM) uses a wide band or multiband OFDM

(MBOFDM) signal that is effectively

a 500 MHz wide OFDM signal

This is 500 MHz signal is then hopped

in frequency to enable it to occupy

a sufficiently high bandwidth.

fi

Frequency Subcarrier(not delta function) To Time

DomainSignal

TD Signal into Freq.Domain

Frequency Subcarrier(not delta function) To Time

DomainSignal

TD Signal into Freq.Domain

f1 f2 fN

UWB Technologies Band Plan for MB OFDM

• Group the 528 MHz bands into 4 distinct groups

• Group A: Intended for 1st generation devices (3.1 – 4.9 GHz)

• Group B: Reserved for future use (4.9 – 6.0 GHz)

• Group C: Intended for devices with improved SOP performance (6.0 – 8.1 GHz)

• Group D: Reserved for future use (8.1 – 10.6 GHz)

f3432MHz

3960MHz

4488MHz

5016MHz

5808MHz

6336MHz

6864MHz

7392MHz

7920MHz

8448MHz

8976MHz

9504MHz

10032MHz

Band#1

Band#2

Band#3

Band#4

Band#5

Band#6

Band#7

Band#8

Band#9

Band#10

Band#11

Band#12

Band#13

GROUP A GROUP B GROUP C GROUP D

Ultra Wideband Technologies

• Complex Signal Processing the carrier less system must rely on relatively complex and sophisticated signal processing techniques to recover the communications data from this noisy environment.[2]

• Inapplicability of super-resolution beam forming Since the theory of beam forming and super resolution beam forming is based on the phase relationships among sinusoidal waveforms, it does not directly apply to UWB systems using pulses

• Antenna Form Factor UWB antennas are relatively small and use various emissions techniques, not necessarily optimal. The “disadvantage” of antenna form factor in connection with UWB consists of the fact that it is largely unknown due to

• the relative novelty of UWB transmission for most communication applications.

Disadvantages of Carrier less Transmission

Information Modulation

• Pulse Position Modulation (PPM)

• Pulse Amplitude Modulation (PAM)

• On-Off Keying (OOK)

• Bi-Phase Modulation (BPSK)

Pulse length ~ 200ps; Energy concentrated in 2-6GHz band;

Voltage swing ~100mV; Power ~ 10uW

15

Challenges

• Main challenge is in the standardization. Different countries allocated different spectral regions for unlicensed use.

• Interference with other licensed bands

• Tradeoffs with noise.

• Design of antenna

• Due to power limit set by FCC, the high data rate is available only in short range ( <10 m)

• Well suited for high speed, short range WPAN.

• Supports multimedia data rates, and offers inherent data security.

• There's a possibility that UWB will become the "next best" technology for all types of wireless networks, including wireless LANs.

• UWB technology has very high potential in real life applications, due to its high bandwidth and low power.

• Very interesting application in wireless content transfer, especially for HD videos.

CONCLUSION

REFRENCES

• Rahman,T.A ,Ngah,R,Hall,P.S. Wireless and Optical Communications Networks, 2009. WOCN '09. 5th IFIP International Conference : 5-7 May 2009

• Liuqing Yang; Giannakis, G.B..”Ultra Wideband communications, An idea whose Time has come.”Signal Processing Magazine, IEEE.Volume 21, Issue 6, Date: Nov. 2007.

• Dr. Jeffrey Reed, Dr. R. Michael Buehrer, Dr. Dong S. Ha, “Introduction to UWB:Impulse Radio for Radar and Wireless Communications”.

• M.Ghavami,L.B. Michael,R.Kohno, “Ultra wideband signals and systems in communication engineering”,2nd Edition.

• Ryuji Kohno and Kenichi Takizawa, “Overview of Research and Development Activities in NICT UWB Consortium,” 2005 IEEE International Conference on Ultra-Wideband, Zurich, Switzerland, pp. 735-740, September 5-8, 2005.

• L.E.Miller , “A Review of Ultra wideband Technology”, Wireless Communication Technologies Group, National Institute of Standards and Technology, Gaithersburg, Maryland.