Method for obtaining channel information and communications apparatus

A method for obtaining channel information, comprising:

• receiving, by a second device, a first reference signal from a first device, wherein a density of the first reference signal is less than or equal to a density of a second reference signal, and the second reference signal is a normal-density reference signal;
• and
• sending, by the second device, first channel state information (CSI) to the first device, wherein the first CSI is used to obtain second CSI using a first neural network model deployed on the first device, the second CSI is used to indicate channel information between the first device and the second device, wherein
• when the density of the first reference signal is less than the density of the second reference signal, the first CSI is obtained by the second device based on the first reference signal, and when the density of the first reference signal is equal to the density of the second reference signal, the first CSI is obtained by the second device based on a part of the first reference signal received on a resource used to receive a low-density reference signal, wherein the first neural network model is updated by the first device based on a preset trigger condition being met, wherein the preset trigger condition includes that a first timer expires, and the first timer is started when the first device sends the first reference signal,
• wherein before the receiving, by a second device, a first reference signal from a first device, the method further comprises:
• sending, by the second device, a second request message to the first device, wherein the second request message is used to request the first reference signal, and the second request message is further used to indicate the density of the first reference signal.

A communications apparatus, comprising a transceiver unit and a processor, wherein the communications apparatus is a first device in a network and wherein

• the transceiver unit is configured to send a first reference signal to a second device, wherein a density of the first reference signal is less than or equal to a density of a second reference signal, and the second reference signal is a normal-density reference signal;
• the transceiver unit is further configured to receive first channel state information (CSI) from the second device, wherein when the density of the first reference signal is less than the density of the second reference signal, the first CSI is obtained by the second device based on the first reference signal, and when the density of the first reference signal is equal to the density of the second reference signal, the first CSI is obtained by the second device based on a part of the first reference signal received on a resource used to receive a low-density reference signal;
• and
• the processor is configured to obtain second CSI based on the first CSI and a first neural network model deployed on the apparatus, wherein the second CSI is used to indicate channel information between the communications apparatus and the second device;
• and
• the processor is configured to update the first neural network model based on a preset trigger condition being met, wherein the preset trigger condition includes that a first timer expires, and the first timer is started when the transceiver unit sends the first reference signal to the second device,
• wherein the transceiver is further configured to, before sending the first reference signal to the second device, receive a second request message from the second device, wherein the second request message is used to request the first reference signal, and the second request message is further used to indicate the density of the first reference signal.