A method for signal transmission, characterized by comprising: a user equipment calculating a mean squared error of a first layer of signal and an MSE of a second layer of signal; the UE selecting a pre-coding matrix from a plurality of pre-coding matrices according to the sum of the MSE of the first layer of signal and the MSE of the second layer of signal; and the UE informing a base station to use the selected pre-coding matrix to transmit signals; wherein the UE selecting a pre-coding matrix from a plurality of pre-coding matrices according to the sum of the MSE of the first layer of signal and the MSE of the second layer of signal comprises: when c ( i) 00 + c ( i) 11 > t, the UE selecting a pre-coding matrix which enables the noise of a layer of signal with good channel to be minimized from the plurality of pre-coding matrices according to formula i=arg min (min (c (i) 00, c (i) 11)), wherein c ( i) 00 is the MSE of the first layer of signal when using the i th pre-coding matrix, c ( i) 11 is the MSE of the second layer of signal when using the i th pre-coding matrix, and t is a set threshold; when c ( i) 00 + c ( i) 11 < t, the UE selecting a pre-coding matrix which enables the noise of a layer of signal with poor channels in the two layers of signal to be minimized from the plurality of pre-coding matrices matrices according to formula i=arg min (max (c (i) 00, c (i) 11)), wherein c ( i) 00 is the MSE of the first layer of signal when using the ith pre-coding matrix, c ( i) 11 is the MSE of the second layer of signal when using the ith pre-coding matrix, and t is a set threshold. a user equipment calculating a mean squared error of a first layer of signal and an MSE of a second layer of signal; the UE selecting a pre-coding matrix from a plurality of pre-coding matrices according to the sum of the MSE of the first layer of signal and the MSE of the second layer of signal; and the UE informing a base station to use the selected pre-coding matrix to transmit signals; wherein the UE selecting a pre-coding matrix from a plurality of pre-coding matrices according to the sum of the MSE of the first layer of signal and the MSE of the second layer of signal comprises: when c ( i) 00 + c ( i) 11 > t, the UE selecting a pre-coding matrix which enables the noise of a layer of signal with good channel to be minimized from the plurality of pre-coding matrices according to formula i=arg min (min (c (i) 00, c (i) 11)), wherein c ( i) 00 is the MSE of the first layer of signal when using the i th pre-coding matrix, c ( i) 11 is the MSE of the second layer of signal when using the i th pre-coding matrix, and t is a set threshold; when c ( i) 00 + c ( i) 11 < t, the UE selecting a pre-coding matrix which enables the noise of a layer of signal with poor channels in the two layers of signal to be minimized from the plurality of pre-coding matrices matrices according to formula i=arg min (max (c (i) 00, c (i) 11)), wherein c ( i) 00 is the MSE of the first layer of signal when using the ith pre-coding matrix, c ( i) 11 is the MSE of the second layer of signal when using the ith pre-coding matrix, and t is a set threshold. when c ( i) 00 + c ( i) 11 > t, the UE selecting a pre-coding matrix which enables the noise of a layer of signal with good channel to be minimized from the plurality of pre-coding matrices according to formula i=arg min (min (c (i) 00, c (i) 11)), wherein c ( i) 00 is the MSE of the first layer of signal when using the i th pre-coding matrix, c ( i) 11 is the MSE of the second layer of signal when using the i th pre-coding matrix, and t is a set threshold; when c ( i) 00 + c ( i) 11 < t, the UE selecting a pre-coding matrix which enables the noise of a layer of signal with poor channels in the two layers of signal to be minimized from the plurality of pre-coding matrices matrices according to formula i=arg min (max (c (i) 00, c (i) 11)), wherein c ( i) 00 is the MSE of the first layer of signal when using the ith pre-coding matrix, c ( i) 11 is the MSE of the second layer of signal when using the ith pre-coding matrix, and t is a set threshold.