Signal transmission method and base station

A base station, comprising:

• a processor, configured to determine, based on whether an output power exceeds a threshold, whether to use a virtual antenna mapping (VAM) matrix to process baseband signals;
• a virtual antenna mapping (VAM) processor, configured to:
• in response to the processor determining to use the VAM matrix to process baseband signals, process a first baseband signal, a second baseband signal, a third baseband signal, and a fourth baseband signal by using a VAM matrix, to obtain four processed signals, wherein the four processed signals comprise a first processed signal, a second processed signal, a third processed signal, and a fourth processed signal, the first processed signal is the same as the third processed signal, the second processed signal is the same as the fourth processed signal, the first processed signal is obtained by performing superposition on the first baseband signal and the third baseband signal, and the second processed signal is obtained by performing superposition on the second baseband signal and the fourth baseband signal;
• a precoding processor, configured to perform precoding processing on the four processed signals obtained by the VAM processor, to obtain four coded signals;
• and
• a transmitter, configured to send, to a mobile terminal by using four radio frequency ports, the four coded signals obtained by the precoding processor, wherein the four radio frequency ports are in a one-to-one correspondence with the four coded signals.

A non-transitory computer readable medium, configured to store program code, and the program code includes an instruction for performing operations comprising:

• determining, by a base station and based on whether an output power exceeds a threshold, whether to use a virtual antenna mapping (VAM) matrix to process baseband signals;
• in response to determining to use the VAM matrix to process baseband signals, processing, by the base station, a first baseband signal, a second baseband signal, a third baseband signal, and a fourth baseband signal by using the VAM matrix, to obtain four processed signals, wherein the four processed signals comprise a first processed signal, a second processed signal, a third processed signal, and a fourth processed signal, the first processed signal is the same as the third processed signal, the second processed signal is the same as the fourth processed signal, the first processed signal is obtained by performing superposition on the first baseband signal and the third baseband signal, and the second processed signal is obtained by performing superposition on the second baseband signal and the fourth baseband signal;
• performing, by the base station, precoding processing on the four processed signals to obtain four coded signals;
• and
• sending, by the base station, the four coded signals to a mobile terminal by using four radio frequency ports, wherein the four radio frequency ports are in a one-to-one correspondence with the four coded signals.