Signal transmission method and apparatus

A signal transmission method, wherein the method comprises:

• receiving signals on M subcarriers, wherein the signals are signals modulated according to π/2-binary phase shift keying (π/2-BPSK), and M is a quantity of subcarriers comprised in a scheduling bandwidth;
• and
• determining an m1th signal and an m2th signal, wherein the m1th signal is determined based on an m1th received signal and an m2th received signal, the m2th signal is determined based on the myth received signal and the m2th received signal, and the m1th signal is equal to a complex conjugate of the m2th signal;
• and
• the myth received signal is a signal received on an m1th subcarrier in the M subcarriers, the m2th received signal is a signal received on an m2th subcarrier in the M subcarriers, the m1th signal is a signal recovered on the m1th subcarrier, and the m2th signal is a signal recovered on the m2th subcarrier.

An apparatus, comprising:

• a processor;
• and
• a computer-readable storage medium storing a program to be executed by the processor, the program including instructions to cause the processor to:
• precode N streams of signals based on a first codebook, to obtain N1 precoded signals,
• wherein a quantity of non-zero elements in each row of the first codebook is 1, the first codebook causes a phase difference between signals sent on two transmit antenna ports, and N and N1 are integers greater than 1;
• and
• send the N1 precoded signals,
• wherein the first codebook belongs to a codebook set, a quantity of non-zero elements in each row of each codebook in the codebook set is 1, and each codebook in the codebook set causes a phase difference between signals sent on two transmit antenna ports;
• when a quantity of transmit antenna ports is 2, each codebook in the codebook set is:
• θ is a phase difference between signals sent on the two transmit antenna ports.