Term Project: ULTRA WIDE-BAND COMMUNICATIONS

April 04, 2007 ECE Dept. – University of Windsor

Ultra Wide-Band Communications

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Term Project:

ULTRA WIDE-BAND COMMUNICATIONS

Prepared and Presented by

Alain Eid



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Contents

• Introduction to UWB• Definition of UWB• IEEE 802.15.3a Standard• Wireless Alternatives• Multi-Bands Design• UWB Transceivers• Technology Challenges• Conclusion



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Chronology Research on UWB

• Is it a New Technology?

The first impulse system patent was awarded in 1954 The basic concept was first described in 1960 The first landmark patent of UWB was awarded in 1973 It has been used since 1980 in military Radar applications The term UWB was first used in 1989 by DoD Up to 1994, all UWB studies were classified A substantial change occurred in 2002 when UWB was made public (by

FCC)

• The Answer is NO



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Definition of UWB

UWB spectral mask for indoor communications systems



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Definition of UWB (Continued)

US Spectrum Allocation for Unlicensed Use



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IEEE 802.15.3a Standard

IEEE 802.15.3a Summary Requirements



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Wireless Alternatives

In order to understand where UWB fits in with the current trends in wireless communications, we need to consider the general problem that communications systems try to solve. Specifically, if wireless were an ideal medium, we could use it to send:

1. a lot of data

2. very far

3. very fast

4. for many users

5. all at once



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Wireless Alternatives (Continued)

• Unfortunately, it is impossible to achieve all five attributes simultaneously for systems supporting unique, private, two-way communication streams.

• One or more have to be given up if the others are to do well. Original wireless systems were built to bridge large distances in order to link two parties together.

• However, recent history of radio shows a clear trend toward improving on the other four attributes at the expense of distance.



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Four trends are driving short-range wireless in general and ultra-wideband in particular:

1. The growing demand for wireless data capability in portable devices at higher bandwidth but lower in cost and power consumption than currently available.

2. Crowding in the spectrum that is segmented and licensed by regulatory authorities in traditional ways.

3. The growth of high-speed wired access to the Internet in enterprises, homes, and public spaces.

4. Shrinking semiconductor cost and power consumption for signal processing.



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Spatial Capacity Comparison Between IEEE 802.11, Bluetooth and UWB



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Channel Capacity for Additive, White Gaussian Noise



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Multi-Bands Design• UWB has been defined in the past as a method to encode

information using impulses.• These impulses can be modulated either with position, or with

amplitude or with phase. • The transmitter feeds these impulses to a very large

bandwidth, non-resonating antenna, or sometimes the antenna itself shapes the impulses to the required frequency of operation.

• UWB companies have developed proprietary techniques to generate and detect such impulses, using non-resonating components.

• These impulses are especially effective for radar systems, where the resolution is proportional to the bandwidth, but have proven difficult to realize in CMOS so far.



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Multi-Bands (Continued)

Multi-Band Signals Sequence



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Multi-Bands (Continued)

Multi-Band Signal Reference



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UWB Transceivers

Multi-Bands Transceiver Block Diagram



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UWB Transceivers (Continued)

UWB Transceiver’s Typical Performance



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UWB Applications

• Desktops and Laptop PCs High resolution printers, scanners, storage devices… Connectivity to mobile and CE devices

• Mobile Devices Multimedia files, MP3, games, video Personal connectivity

• CE Devices Cameras, DVD, HDTV Personal connectivity

• Military Communications• Radars and Sensing



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Technology Challenges

• Short-range wireless systems based on narrowband carrier modulation VS High data rates to transmit video over air.

• Spatial capacity VS System performance and spectral efficiency of UWB radio devices.



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Technology Challenges (Continued)

• Mutual interference between UWB devices VS Level of QoS.

• Modulation and channel coding VS Multi-User capacity.

• Peak power VS Optimization of transmission techniques.

• Excessive clock speed, synchronization, power consumption VS MEMS and SOI



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Conclusion

• The recently FCC frequency allocation for UWB has generated a lot of interest in UWB technologies.

• 7500MHz of spectrum for unlicensed use.• Transmit signal must occupy at least 500MHz at whole

times.• UWB is the most promising technology to support the

rigorous requirements: 110, 200 and 480Mbps.• The new UWB technology emerging today, mostly as a

consequence of the recent FCC spectrum allocation, is based on multi-bands.

• There are still many technology’s challenges ahead, mostly around the high level of integration that UWB products requires: they need to be developed at low cost and low power to meet the vision of integrated connectivity for PAN.

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Term Project: ULTRA WIDE-BAND COMMUNICATIONS