Diversity for direct-sequence spread spectrum systems

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United States of America Patent

PATENT NO 5394435
SERIAL NO

08200090

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Abstract

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An invention for providing diversity for direct sequence spread spectrum wireless communication systems is presented. The invention provides a transmitting technique for communicating a first signal comprising one or more segments to a receiver with use of a plurality of M antennas. The first signal includes one or more signal segments. The technique comprises forming M copies of the first signal; for a segment of a signal copy, weighting each of two or more sub-segments of the segment with a distinct signal, wherein a sequence of the distinct weighting signals for the segment is distinct from sequences of signals weighting the same segment of one or more other signal copies; and for each of M weighted signal copies, transmitting a signal to the receiver using a distinct antenna, the transmitted signal based on the weighted signal copy. Illustratively, the first signal is a spread spectrum signal. Moreover, the process of weighting comprises applying a phase shift to a sub-segment. The invention further provides a receiving technique which comprises, for a copy of a received signal, despreading a segment of the received signs, demodulating a plurality of sub-segments of the despread signal segment, wherein each sub-segment is demodulated with use of one or more estimated communication channel characteristics corresponding to the sub-segment, and forming a summation signal reflecting a summation of a plurality of demodulated sub-segments. The receiving technique further comprises forming a signal reflecting a signal segment value, the formed signal based on one or more summation signals. The step of demodulating may precede the step of despreading in some embodiments.

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Patent Owner(s)

Patent OwnerAddress
AMERICAN TELEPHONE AND TELEGRAPH COMPANY550 MADISON AVENUE NEW YORK NEW YORK 10022 UNITED STATES OF AMERICA

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Weerackody, Vijitha Springfield, NJ 22 1332

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