Patent ID: 7200164

Claim:
A complementary code keying (CCK) demodulator used in a RAKE receiver receiving CCK symbols in a multipath environment, the CCK demodulator comprising: multipath interference estimation means, using feedback and feed-forward tap weights as inputs to a modified Fast Walsh Transform (FWT) based CCK correlator for jointly calculating a plurality of post-correlation intra-codeword chip interference (ICI) bias during a preamble period; decoding means, using the same modified FWT based CCK correlator during a CCK data period for computing the correlation between the received CCK symbol and all possible CCK codewords, and then finding an index of a CCK codeword having the maximum correlation between the received CCK symbol and all possible CCK codewords, with the post-correlation ICI bias due to the received present (“to-be-decoded”) CCK symbol removed; and wherein the modified FWT based CCK correlator, using a Fast Multipath/Walsh Transform (FMWT) block as its basic building blocks, forms an optimum CCK demodulator in the absence of multipath propagation.