Patent ID: 6678310
Filing Date: 2004-01-13
Classification: H04B,H04L,H04W

Abstract:
A spread spectrum radio transceiver comprising:a baseband processor and a radio circuit connected thereto, said baseband processor comprising a demodulator for spread spectrum phase shift keying (PSK) demodulating an information signal received from the radio circuit, wherein said information signal includes data symbols formed from a plurality of high rate mode chips forming a spread spectrum information signal, said demodulator further comprising a signal input for receiving said information signal; an input mixer circuit for receiving said signal input; at least one predetermined code function correlator in line with the input mixer circuit for decoding the information signal according to a predetermined code; an automatic gain control/carrier loop circuit for phase and frequency tracking the information signal and having an output to the input mixer circuit; a chip decision circuit and logical mixer operative in a feedback loop with the automatic gain control/carrier loop circuit for outputting an error signal to the automatic gain control/carrier loop circuit for tracking high rate mode chips; an equalizer circuit comprising: a feed forward finite impulse response filter positioned in line to said code function correlator and receiving an output from said input mixer circuit, and having a plurality of feed forward taps, wherein at least one feed forward tap is selected for logical multiply operations to aid in reducing multipath signal echoes, such as caused by multipath, and a logical mixer in-line with said code function correlator and receiving an output from said feed forward finite impulse response filter; a feedback finite impulse response filter operative in a feedback loop with said chip decision circuit and outputting a signal to said logical mixer that also receives the output of the feed forward finite impulse response filter, and having a plurality of feedback taps, wherein at least one feedback tap is selected for logical add/subtract operations to aid in canceling multipath signal echoes; wherein the carrier loop circuit is operative for processing the error signal from the chip decision circuit and logical mixer and operative with said feed forward finite impulse response filter such that maximum phase channel components are processed by the feed forward finite impulse response filter to determine channel impulse response and minimum phase channel components are processed by the feedback finite impulse response filter by convolving channel impulse response with feed-forward weights; and a modulator for spread spectrum PSK modulating information for transmission via the radio circuit, said modulator comprising at least one code function encoder for encoding information according to an orthogonal code sequence.