Interference canceller for CDMA

摘要

A code-orthogonalizing filter 101 performs inverse spread using an orthogonalizing coefficient, which is obtained through a constraint condition process on a code multiplexed received signal as an input with a desired spread code waveform and independent on transmission line variations, thus detecting a desired wave at a constant power level while suppressing interference waves. A carrier tracking circuit 102 effects carrier phase synchronization of the detected desired wave. A symbol decision unit 104 decides the output of the carrier tracking circuit 102 to be the most certain symbol. An adder 104 extracts as symbol decision error signal from the outputs of the symbol decision unit 103 and the carrier tracking circuit 102. A tap coefficient control means 105 adaptively updates the tap coefficient according to the input to the code-orthogonalizing filter 101, a reproduced carrier outputted from the carrier tracking circuit 102, a symbol decision error signal outputted from the adder 104 and the desired wave spread code waveform.