Spread spectrum communication method and system using diversity correlation and multi-user detection

Abstract

A communication system transmits and receives a plurality of spread-spectrum signals having differences in at least one diversity parameter. The signals are highly correlated when their diversity parameters are similar, and the signals are uncorrelated when at least one diversity parameter is different Any combination of a transmitter, a receiver, and a communication channel may diversity-encode the signals to effect differences in their diversity parameters. A receiver diversity-decoder compensates for differences in a diversity-parameter of at least one received signal to make the signal highly correlated with at least one other received signal. A correlator combines at least two of the received signals to recover an embedded information signal. The communication system enables the use of true-noise signals for spreading information signals, provides simplified receiver designs, and enables antenna arrays to spatially process spread-spectrum signals.

1 .- 13 . (canceled) 
     
     
         14 . A method of extracting information signals from a plurality of received spread-spectrum signals, the method comprising:
 receiving the spread-spectrum signals, at least one of the spread-spectrum signals being a diversity-encoded spread-spectrum signal,   decoding at least one of the diversity-encoded spread-spectrum signals to obtain a decoded signal, and   correlating the decoded signal with at least one of the spread-spectrum signals to produce a correlation signal that is indicative of information encoded in the spread-spectrum signals.   
     
     
         15 . A method of extracting information signals from a plurality of received spread-spectrum signals, the method comprising:
 receiving the spread-spectrum signals and at least one spectrum-decoding signal, at least one of the spread-spectrum signals or the spectrum-decoding signal being a diversity-encoded spread-spectrum signal,   decoding at least one of the diversity-encoded signals to provide at least one diversity-decoded signal, and   correlating the diversity-decoded signal with at least one of the spread-spectrum signals or the spectrum-decoding signal to produce a correlation signal that is indicative of information encoded in the spread-spectrum signals.   
     
     
         16 .- 17 . (canceled) 
     
     
         18 . A spread-spectrum receiver for extracting an information signal from a plurality of spectrum-coded, diversity-coded signals, the receiver comprising:
 a receiving system to receive the spectrum-coded, diversity-coded signals,   a diversity processor coupled to the receiving system to diversity decode at least one of the received signals to provide a plurality of signals that are highly correlated, and   a signal combiner coupled to the diversity processor or otherwise combine the plurality of highly correlated signals to generate a correlation signal indicative of the information signal.   
     
     
         19 . A spread-spectrum receiver for extracting an information signal from at least one spectrum-coded, diversity-coded signal, the receiver comprising:
 a receiving system to receive the at least one spectrum-coded, diversity-coded signal and to receive at least one despreading signal, the received despreading signal being separable from the at least one spectrum-coded signal,   a diversity processor coupled to the receiving system to diversity decode at least one of the received signals to generate a plurality of signals that are highly correlated, and   a signal combiner coupled to the diversity processor or otherwise combine the plurality of highly correlated signals to generate a correlation signal indicative of the information signal.   
     
     
         20 . The method according to  claim 15 , wherein said spectrum-decoding signal is received distinctly from the spread-spectrum signals. 
     
     
         21 . The receiver according to  claim 19 , wherein said despreading signal is received distinctly from the at least one spectrum-coded, diversity-coded signal. 
     
     
         22 . The receiver according to  claim 18 , wherein said receiving system comprises an array of receiving elements. 
     
     
         23 . The receiver according to  claim 19 , wherein said receiving system comprises an array of receiving elements. 
     
     
         24 . The receiver according to  claim 18 , wherein said signal combiner comprises a multi-user detector. 
     
     
         25 . The receiver according to  claim 24 , wherein said multi-user detector comprises a weight-and-sum canceller. 
     
     
         26 . The receiver according to  claim 19 , wherein said signal combiner comprises a multi-user detector. 
     
     
         27 . The receiver according to  claim 26 , wherein said multi-user detector comprises a weight-and-sum canceller. 
     
     
         28 . The method according to  claim 14 , wherein said correlating comprises performing multi-user detection. 
     
     
         29 . The method according to  claim 28 , wherein said multi-user detection comprises weight-and-sum cancellation. 
     
     
         30 . The method according to  claim 14 , further comprising:
 generating a set of weighting factors to be used in said combining.   
     
     
         31 . The method according to  claim 30 , wherein said generating a set of weighting factors is performed based on a received training sequence of reference symbols. 
     
     
         32 . The method according to  claim 15 , wherein said correlating comprises performing multi-user detection. 
     
     
         33 . The method according to  claim 30 , wherein said multi-user detection comprises weight-and-sum cancellation. 
     
     
         34 . The method according to  claim 15 , further comprising:
 generating a set of weighting factors to be used in said combining.   
     
     
         35 . The method according to  claim 34 , wherein said generating a set of weighting factors is performed based on a received training sequence of reference symbols.