Motorola Corporation

Douglas I Averst

Stephen Rocco Carsello

Tony R Branch

Joseph C Liberti, Jr

Warren P Glotzbach

A method and apparatus diversity-combine radio signals received from a plurality of branches (108, 214). Each radio signal comprises a plurality of subchannels (806). The radio signal from each branch (108, 214) is digitized (904) into digital samples that are converted (908, 910) into frequency domain signals (702, 712). Each frequency domain signal (702, 712) corresponds to a subchannel and a branch (108, 214). A weighting factor is determined (916) for each branch (108, 214) and each subchannel (806) from instantaneous signal energy and noise power calculated (912, 914) from the frequency domain signals (702, 712). The frequency domain signal (702, 712) corresponding to each branch (108, 214) and each subchannel (806) is multiplied (918) by the weighting factor therefor to produce weighted frequency domain signals corredponding to each branch and each subchannel. The weighted frequency domain signals that correspond to all the branches (108, 214) of each subchannel (806) are then combined (920) to produce a diversity-combined frequency domain signal for each subchannel (806).

Method and apparatus for Fast Fourier Transform based maximal ratio

A frequency shift keyed receiver (214, 220, 218) estimates a carrier frequency and demodulates (1020) a symbol value associated with the carrier frequency. During symbol intervals, the receiver (214, 220, 218) receives a radio signal including symbol values (502-518) corresponding to predetermined frequency offsets (604, 606) from a carrier frequency. The radio signal is digitized (1008) during a symbol interval, and then converted (1010) into a frequency domain signal. The frequency domain signal is stored (1012), and additional symbol intervals are converted to obtain a plurality of frequency domain signals, which are processed to generate (1016) a composite frequency domain signal (702, 704). A windowing function (706) of predetermined shape is convolved (1018) with the composite frequency domain signal (702, 704) to locate a frequency distribution therein that corresponds to the predetermined frequency offsets (604, 606). The carrier frequency (708) is estimated from the location of the frequency distribution, and utilized to demodulate (1020) the symbol values.

Method and apparatus for carrier tracking and demodulation

A method for receiving and processing data in a portable transceiver (20) comprises the steps of receiving (320) at least one information signal and decoding (325) the at least one information signal to recover information included therein. The method further comprises the steps of generating (345) a pseudo-noise (PN) sequence in accordance with the information.

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Delray Beach, FL, United States of America

Douglas I Averst