Spread spectrum transmitter and spread spectrum receiver

A spread spectrum receiver comprising:

• a partial correlation calculating unit that holds partial spreading codes obtained by dividing spreading codes employed in a spread spectrum transmitter by a bit number J of orthogonal code sequences, and calculates partial correlation values between a transmission multiplex spread spectrum signal transmitted from the spread spectrum transmitter and the partial spreading codes, the spread spectrum transmitter including
• a serial-parallel converting unit that inputs an information signal, sequentially converts the information signal into parallel data sequences of a prescribed data length, and sequentially distributes the parallel data sequences to N channels, where N is 2 or greater natural number,
• an orthogonal sequence encoding unit that sequentially converts the parallel data sequences into prescribed orthogonal code sequences,
• a spreading modulating unit that performs a spectrum spreading modulation process by respectively multiplying the orthogonal code sequences by prescribed spreading codes to output N spread spectrum signals,
• a delay unit that provides delays having different magnitudes to the N spread spectrum signals,
• a multiplexing unit that multiplexes the N spread spectrum signals in a prescribed manner to generate a transmission multiplex spread spectrum signal, and
• a transmitting unit that performs prescribed signal processing for transmitting the transmission multiplex spread spectrum signal;
• an inverse matrix multiplying unit that holds an inverse matrix of an orthogonal code matrix having the orthogonal code sequences employed in the spread spectrum transmitter as row elements of the orthogonal code sequences, and multiplies the inverse matrix by a column vector consisting of the partial correlation values to calculate orthogonal correlation values respectively corresponding to the orthogonal code sequences;
• a most-likelihood deciding/demodulating unit that identifies an orthogonal code sequence having an orthogonal correlation value as a maximum, to output a parallel data sequence related in advance to the orthogonal code sequence, as a demodulated parallel data sequence, to a respective one of N channels;
• a delay difference correcting unit that corrects delay differences of the demodulated parallel data sequences of the channels depending on delay amounts provided to the spread spectrum signals in the channels of the spread spectrum transmitter;
• and
• a demodulation data converting unit that samples the demodulated parallel data sequences after delay difference correction depending on a reproduced symbol clock synchronized to a cyclic period of spreading code of the transmission multiplex spread spectrum signal, and parallel-serial converts the sampled data of the channels to obtain a serial demodulated data sequence.