Biased-corrected rake receiver for direct sequence spread spectrum waveform

摘要

The performance of a RAKE receiver for indoor multipath WLAN applications on direct sequence spread spectrum signals having relatively short codeword lengths comprises a channel-matched filter and codeword correlator front end, plus a signal combiner to which the codeword correlation component is applied. The signal combiner is supplied with a bias-corrected input calculated by a distorted codeword signature (power) generator, which is operative to generate and store a set of N codeword power correction values. The signal combiner combines correction values into the codeword correlation for each potentially transmitted codeword S_k. This serves to correct each correlation codeword metric by a de-biasing power component S_k² for the unequal multipath-based distortions of the codeword energies. The output of the signal combiner is coupled to a peak detector, which selects a minimum distance-based de-biased output as the transmitted codeword.