Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via code word channels
Patent
1997-12-01
1999-06-29
Vu, Huy D.
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via code word channels
H04J 1300
Patent
active
059178299
ABSTRACT:
Method and apparatus for optimally decoding messages from CDMA signal sent by a plurality of users and received asynchronously at one receiver, using a minimal number of computations and minimal memory and processing resources. It is based on a novel approach to signal correlation, as well as to subsequent decoding by decorrelation, that requires a correlation period of only one symbol length, by providing for each user a pair of partial signatures sequences, with which the signal is correlated, deccorelating the results with the inverse of the cross-correlation matrix of all partial sequences, and combining the resultant partial symbol estimates--to obtain final estimated symbol values. The partial sequences are formed by separating each original sequence at a point corresponding to the estimated symbol boundary time, relative to an arbitrary correlation window, of one symbol length. The method can be modified to also apply to the case that any of the signals is received over multiple paths, any path possibly undergoing Doppler shift.
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Greenberger Harvey J.
Hertz David
Boakye Alexander
Friedman Mark M.
State of Israel-Ministry of Defense, Rafael - Armament Developme
Vu Huy D.
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