A signal processing method, applied to a transmitter device, wherein the method comprises: sending m training signals in parallel using m transmit antenna groups, wherein m is an integer greater than or equal to 1; receiving a first mixed signal obtained by superimposing the m training signals in space, wherein: a phase difference between the first mixed signal and a second mixed signal falls within a preset range, implemented by: adjusting a phase of a k th training signal of the m training signals to a target phase ξ k, so that the phase difference between the first mixed signal and the second mixed signal falls within the preset range, wherein k=1,2,...,m is traversed, and k is an integer; and obtaining the target phase ξ k based on φ k and γ k, wherein φ k is a phase when the k th training signal arrives at the receiver device through space transmission, and γ k is a difference between a phase of the k th training signal and a phase when the k th training signal arrives, through space transmission, at a target feedback antenna that is in the transmitter device and that is configured to receive the first mixed signal, wherein the obtaining the target phase ξ k based on φ k and γ k comprises obtaining the target phase ξ k according to a formula ξ k = φ k - γ k; and the second mixed signal is a signal received by a receiver device and obtained by superimposing the m training signals in space; performing digital pre-distortion, DPD, parameter estimation based on the first mixed signal to obtain a DPD parameter, and performing pre-distortion processing on a to-be-sent signal based on the DPD parameter; and sending the to-be-sent signal on which pre-distortion processing has been performed. sending m training signals in parallel using m transmit antenna groups, wherein m is an integer greater than or equal to 1; receiving a first mixed signal obtained by superimposing the m training signals in space, wherein: a phase difference between the first mixed signal and a second mixed signal falls within a preset range, implemented by: adjusting a phase of a k th training signal of the m training signals to a target phase ξ k, so that the phase difference between the first mixed signal and the second mixed signal falls within the preset range, wherein k=1,2,...,m is traversed, and k is an integer; and obtaining the target phase ξ k based on φ k and γ k, wherein φ k is a phase when the k th training signal arrives at the receiver device through space transmission, and γ k is a difference between a phase of the k th training signal and a phase when the k th training signal arrives, through space transmission, at a target feedback antenna that is in the transmitter device and that is configured to receive the first mixed signal, wherein the obtaining the target phase ξ k based on φ k and γ k comprises obtaining the target phase ξ k according to a formula ξ k = φ k - γ k; and the second mixed signal is a signal received by a receiver device and obtained by superimposing the m training signals in space; a phase difference between the first mixed signal and a second mixed signal falls within a preset range, implemented by: adjusting a phase of a k th training signal of the m training signals to a target phase ξ k, so that the phase difference between the first mixed signal and the second mixed signal falls within the preset range, wherein k=1,2,...,m is traversed, and k is an integer; and obtaining the target phase ξ k based on φ k and γ k, wherein φ k is a phase when the k th training signal arrives at the receiver device through space transmission, and γ k is a difference between a phase of the k th training signal and a phase when the k th training signal arrives, through space transmission, at a target feedback antenna that is in the transmitter device and that is configured to receive the first mixed signal, wherein the obtaining the target phase ξ k based on φ k and γ k comprises obtaining the target phase ξ k according to a formula ξ k = φ k - γ k; and adjusting a phase of a k th training signal of the m training signals to a target phase ξ k, so that the phase difference between the first mixed signal and the second mixed signal falls within the preset range, wherein k=1,2,...,m is traversed, and k is an integer; and obtaining the target phase ξ k based on φ k and γ k, wherein φ k is a phase when the k th training signal arrives at the receiver device through space transmission, and γ k is a difference between a phase of the k th training signal and a phase when the k th training signal arrives, through space transmission, at a target feedback antenna that is in the transmitter device and that is configured to receive the first mixed signal, wherein the obtaining the target phase ξ k based on φ k and γ k comprises obtaining the target phase ξ k according to a formula ξ k = φ k - γ k; and the second mixed signal is a signal received by a receiver device and obtained by superimposing the m training signals in space; performing digital pre-distortion, DPD, parameter estimation based on the first mixed signal to obtain a DPD parameter, and performing pre-distortion processing on a to-be-sent signal based on the DPD parameter; and sending the to-be-sent signal on which pre-distortion processing has been performed.