Patent ID: 7400608
Filing Date: 2008-07-15
Classification: H04B

Abstract:
1. An interference cancellation circuit for use in a spread spectrum code division multiple access (CDMA) receiver, the interference cancellation circuit comprising: a first despreader circuit for despreading a received spread spectrum signal for each path of each CDMA code in the received spread spectrum signal; a first decision circuit coupled to the despreader circuit for performing a decision for each information symbol of each CDMA code in the received spread spectrum signal; a channel estimation circuit coupled to the despreader circuit for obtaining an estimate of the channel medium for each path of each CDMA code in the received spread spectrum signal; a regeneration circuit coupled to the decision circuit and channel estimation circuit for providing a regenerated spread spectrum signal estimate by regenerating and summing the received signals for each signal path of each CDMA code in the received spread spectrum signal; a multiplier circuit coupled to the decision circuit and channel estimation circuit, for providing an interference-free estimate for each despread signal path of each CDMA code in the received spread spectrum signal; a second despreader circuit coupled to the regeneration circuit, for despreading the regenerated signal estimate for each path of each CDMA code in the received spread spectrum signal; an adder circuit coupled to the first despreader circuit for adding the estimate of the interference-free despread signal path to the corresponding despread received signal path for each path of each CDMA code in the received spread spectrum signal; a subtractor circuit coupled to the adder circuit for subtracting the despread regenerated signal estimate from an output of the adder for each path of each CDMA code in the received spread spectrum signal; and a second decision circuit coupled to the subtractor circuit for performing a decision for the information symbol of each CDMA code in the received spread spectrum signal.