A signal sending method, comprising: grouping orthogonal frequency division multiplexing, OFDM, subcarriers in a spectrum into edge subcarriers of the spectrum and non-edge subcarriers of the spectrum according to user requirement of flexible adjustment between outband interference suppression intensity and data throughput; precoding data to be sent to obtain modulated symbols of the data on the subcarriers, wherein the precoding makes every two adjacent edge subcarriers of the spectrum in the edge subcarriers of the spectrum carry a pair of modulated symbols with opposite polarities, and makes each of the non-edge subcarriers of the spectrum carry a modulated symbol with no polarity, wherein the pair of modulated symbols with opposite polarities is obtained from one single symbol, and a first modulated symbol of the pair is equal to the single symbol, while a second symbol of the pair is equal to the single symbol affected by a -1 factor, and the modulated symbol with no polarity is a modulated symbol without being affected by a -1 factor; and sending the modulated symbols of the data on the subcarriers; wherein the grouping the OFDM subcarriers in the spectrum into the edge subcarriers of the spectrum and the non-edge subcarriers of the spectrum according to user requirement of flexible adjustment between the outband interference suppression intensity and the data throughput comprises: grouping the OFDM subcarriers in the spectrum into the edge subcarriers of the spectrum and the non-edge subcarriers of the spectrum based on a predefined first number; if it is required to accomplish a tradeoff between data throughput and outband interference suppression intensity, letting the first number of subcarriers at edge of the spectrum be the edge subcarriers of the spectrum, and letting subcarriers other than the edge subcarriers in the spectrum be the non-edge subcarriers of the spectrum; if it is required to increase the data throughput, letting less than the first number of subcarriers at the edge of the spectrum be the edge subcarriers of the spectrum; if it is required to enhance the outband interference suppression intensity, letting more than the first number of subcarriers at the edge of the spectrum be the edge subcarriers of the spectrum. grouping orthogonal frequency division multiplexing, OFDM, subcarriers in a spectrum into edge subcarriers of the spectrum and non-edge subcarriers of the spectrum according to user requirement of flexible adjustment between outband interference suppression intensity and data throughput; precoding data to be sent to obtain modulated symbols of the data on the subcarriers, wherein the precoding makes every two adjacent edge subcarriers of the spectrum in the edge subcarriers of the spectrum carry a pair of modulated symbols with opposite polarities, and makes each of the non-edge subcarriers of the spectrum carry a modulated symbol with no polarity, wherein the pair of modulated symbols with opposite polarities is obtained from one single symbol, and a first modulated symbol of the pair is equal to the single symbol, while a second symbol of the pair is equal to the single symbol affected by a -1 factor, and the modulated symbol with no polarity is a modulated symbol without being affected by a -1 factor; and sending the modulated symbols of the data on the subcarriers; wherein the grouping the OFDM subcarriers in the spectrum into the edge subcarriers of the spectrum and the non-edge subcarriers of the spectrum according to user requirement of flexible adjustment between the outband interference suppression intensity and the data throughput comprises: grouping the OFDM subcarriers in the spectrum into the edge subcarriers of the spectrum and the non-edge subcarriers of the spectrum based on a predefined first number; if it is required to accomplish a tradeoff between data throughput and outband interference suppression intensity, letting the first number of subcarriers at edge of the spectrum be the edge subcarriers of the spectrum, and letting subcarriers other than the edge subcarriers in the spectrum be the non-edge subcarriers of the spectrum; if it is required to increase the data throughput, letting less than the first number of subcarriers at the edge of the spectrum be the edge subcarriers of the spectrum; if it is required to enhance the outband interference suppression intensity, letting more than the first number of subcarriers at the edge of the spectrum be the edge subcarriers of the spectrum. grouping the OFDM subcarriers in the spectrum into the edge subcarriers of the spectrum and the non-edge subcarriers of the spectrum based on a predefined first number; if it is required to accomplish a tradeoff between data throughput and outband interference suppression intensity, letting the first number of subcarriers at edge of the spectrum be the edge subcarriers of the spectrum, and letting subcarriers other than the edge subcarriers in the spectrum be the non-edge subcarriers of the spectrum; if it is required to increase the data throughput, letting less than the first number of subcarriers at the edge of the spectrum be the edge subcarriers of the spectrum; if it is required to enhance the outband interference suppression intensity, letting more than the first number of subcarriers at the edge of the spectrum be the edge subcarriers of the spectrum.