A communication method and apparatus, a network device, a terminal device, and a system. The method includes: a network device sends a first reference signal to a terminal device through a first port in a first preset subframe corresponding to a first antenna and sends a second reference signal to the terminal device through the first port in a second preset subframe corresponding to a second antenna. Then, the network device receives first measurement information and second measurement information that are sent by the terminal device, where the first measurement information is measurement information of the first reference signal, and the second measurement information is measurement information of the second reference signal. The network device may determine an antenna weight based on the first measurement information and the second measurement information.