Transmitter and receiver

A receiver comprising:

• a correlation processor to find a correlation between a plurality of orthogonal signals that are mutually orthogonal and an input signal obtained from a signal received from an opposing transmitter;
• and
• a determiner to:
• determine, based on the correlation found by the correlation processor, which of the orthogonal signals has been transmitted by the opposing transmitter, and
• restore an information word corresponding to a determined orthogonal signal based on an association between the information words and the orthogonal signals determined based on a size of differences between a plurality of mutually different information words and an inter-signal point distance between the orthogonal signals;
• wherein
• the association between the information words and the orthogonal signals is determined by at least one of the following:
• among the combinations of the information words, associating combinations for which the size of the difference is maximum with, among combinations of the orthogonal signals, combinations for which the inter-signal point distance is maximum;
• and
• among the combinations of the information words, associating combinations for which the size of the difference is minimum with, among the combinations of orthogonal signals, combinations for which the inter-signal point distance is minimum.

A receiver, comprising:

• a correlation processor to find a correlation between a plurality of orthogonal signals that are mutually orthogonal and an input signal obtained from a signal received from an opposing transmitter;
• and
• a determiner to:
• determine, based on the correlation found by the correlation processor, which of the orthogonal signals has been transmitted by the opposing transmitter, and
• restore an information word corresponding to a determined orthogonal signal based on an association between the information words and the orthogonal signals determined based on a size of differences between a plurality of mutually different information words and a probability of occurrence of determination errors between the orthogonal signals;
• wherein
• the orthogonal signals are bi-orthogonally modulated;
• the signal received from the opposing transmitter is a signal transmitted by the transmitter after rotating phase of modulation symbols by phase rotation amounts that differ from one another according to a transmission timing of the modulation symbols;
• and
• the receiver further comprises a phase rotator that rotates phase of the input signal obtained from the signal received from the opposing transmitter to cancel the phase rotated in the transmitter, and that inputs the phase-rotation-canceled signal to the correlation processor.