receiving, by a terminal device, first signaling, wherein the first signaling comprises first modulation and coding scheme (MCS) information;

determining, by the terminal device, at least one parameter based on the first MCS information, wherein the at least one parameter indicates a first reference signal pattern, and the at least one parameter comprises a reference signal additional position, the reference signal additional position determined based on a correspondence between the first MCS information, reference signal sending period information, and the reference signal additional position; and

sending, by the terminal device, an uplink reference signal based on the first reference signal pattern.