Wednesday, October 01, 2008

Different industrial viewpoints in standardization of UWB technology

Multiband-OFDM Alliance (MBOA)
• Initially led by Intel, later on many big players like Microsoft, Panasonic, Samsung, Texas Instruments
formed alliance to propose Multiband-OFDM based UWB standard. The multiband approach takes
7.5 GHz of unlicensed UWB spectrum and divides it into 15 non-overlapping frequency bands. It
complies with the FCC regulation by ensuring that the individual bands occupy between 500MHz and
700MHz. The Multiband approach based on OFDM is supported by a QPSK modulation pushed by
Texas Instruments.
• The multi-band approach adds technical complexity, requires more power and increase upfront costs.
Also, the aggregate power of all the different pulse streams would have to fall within strict FCC
regulations, meaning the tradeoff with range/data transfer will be an issue.
• Multiband systems have improved multi-path energy collection that increases the potential range of
transmissions however this introduces increased receiver complexity (i.e. multiple RF receive chains),
power consumption, analog die size and increased design time. The multi-band system using
orthogonal frequency division multiplexing (OFDM) proposed by the MBOA has several advantages.
Transmitting information on each of the sub-bands increases the high spectral efficiency, inherent
resilience to RF interference, robustness to multi-path, and the ability to efficiently capture multi-path
energy.
DS-CDMA UWB
• Led by XtremeSpectrum/Motorola, nine companies formed the Alliance. The founding member
companies include Appairent Technologies, Inc., Eastman Kodak Company, Hewlett Packard,
Motorola, Inc., Royal Philips Electronics, Samsung Electronics Co. Ltd., Sharp Laboratories of
America, Inc., Time Domain Corporation and XtremeSpectrum, Inc.
• These companies are proposing direct sequence based CDMA modulation for UWB signals which is
very different from the MBOA proposal. The International Telecommunications Union's radio branch is
likely to endorse the XtremeSpectrum/Motorola direct-sequence CDMA ultra-wideband proposal now
before the IEEE 802.15.3a study group.

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