Transmission system and transmission method

A method implemented by a sending apparatus, wherein the method comprises:

• obtaining N to-be-transmitted signals and an encoding coefficient group, wherein the N to-be-transmitted signals are represented as an N×1 signal matrix (X), wherein the encoding coefficient group is represented as an N×N encoding matrix (T), wherein first positive/negative signs of elements in a column of T are the same, wherein second positive/negative signs of elements in remaining N−1 columns of T satisfy a first relationship, and wherein the first relationship comprises:
• when N is an even number:
• a first quantity of elements with positive signs in a column of the remaining N−1 columns is N/2;
• and
• a second quantity of elements with negative signs in a column of the remaining N−1 columns is N/2;
• and
• when N is an odd number, the first quantity is (N−1)/2 and the second quantity is (N+1)/2, and
• wherein N is an integer ≥2;
• processing, based on the encoding coefficient group, the N to-be-transmitted signals to generate N encoded first signals, wherein the N encoded first signals are represented as a signal matrix (Y), and wherein Y=T×X;
• and
• sending, to N signal channels, the N encoded first signals, wherein a signal on each of the N signal channels corresponds to an element in a row of Y.

A method implemented by a receiving apparatus, wherein the method comprises:

• receiving N second signals that are obtained after N encoded first signals pass through N signal channels, wherein the N encoded first signals are based on N to-be-transmitted signals and an encoding coefficient group, wherein the encoding coefficient group is represented as an N× N orthogonal encoding matrix (T), wherein first positive/negative signs of elements in a column of T are the same, wherein second positive/negative signs of elements in remaining N−1 columns in T satisfy a first relationship:
• when N is an even number:
• a first quantity of elements with positive signs in a column of the remaining N−1 columns is N/2;
• and
• a second quantity of elements with negative signs in a column of the remaining N−1 columns is N/2;
• and
• when N is an odd number, the first quantity is (N+1)/2 and the second quantity is (N−1)/2;
• and
• processing the N second signals to obtain signals corresponding to the N to-be-transmitted signals.