A method for supporting a robust channel, RC, coding and modulation performed by an apparatus, wherein the method comprises: forming, on an interface between a physical media dependent, PMD, layer and a physical media specific transmission convergence, PMS-TC, layer, a data frame by using bit data to be carried in a discrete multi-tone, DMT, symbol, wherein the bit data to be carried in the DMT symbol comprises RC bit data that is obtained from an RC channel and service bit data that is obtained from a service data channel; determining first-part bit data in the data frame as uncoded bit data on the interface between the PMD layer and the PMS-TC layer, wherein the first-part bit data comprises the RC bit data, and coding second-part bit data in the data frame to obtain coded bit data, wherein the data frame comprises the first-part bit data and the second-part bit data; and mapping, at the PMD layer, the uncoded bit data and the coded bit data onto multiple subcarriers corresponding to the data frame, and performing modulation to obtain modulated subcarriers, wherein the multiple subcarriers corresponding to the data frame comprise at least one RC subcarrier, and the RC bit data is mapped onto the at least one RC subcarrier; characterized in that: the coded bit data and the uncoded bit data are mapped respectively onto a first portion and a second portion of bits of each subcarrier in the multiple subcarriers, and the second portion of bits is the more significant bits than the first portion of bits; wherein the determining first-part bit data in the data frame as uncoded bit data comprises: obtaining an amount of uncoded bit data carried in each subcarrier of the multiple subcarriers corresponding to the data frame; and calculating a sum of amounts of uncoded bit data carried in the multiple subcarriers, and using the sum as an amount of the first-part bit data in the data frame. forming, on an interface between a physical media dependent, PMD, layer and a physical media specific transmission convergence, PMS-TC, layer, a data frame by using bit data to be carried in a discrete multi-tone, DMT, symbol, wherein the bit data to be carried in the DMT symbol comprises RC bit data that is obtained from an RC channel and service bit data that is obtained from a service data channel; determining first-part bit data in the data frame as uncoded bit data on the interface between the PMD layer and the PMS-TC layer, wherein the first-part bit data comprises the RC bit data, and coding second-part bit data in the data frame to obtain coded bit data, wherein the data frame comprises the first-part bit data and the second-part bit data; and mapping, at the PMD layer, the uncoded bit data and the coded bit data onto multiple subcarriers corresponding to the data frame, and performing modulation to obtain modulated subcarriers, wherein the multiple subcarriers corresponding to the data frame comprise at least one RC subcarrier, and the RC bit data is mapped onto the at least one RC subcarrier; characterized in that: the coded bit data and the uncoded bit data are mapped respectively onto a first portion and a second portion of bits of each subcarrier in the multiple subcarriers, and the second portion of bits is the more significant bits than the first portion of bits; wherein the determining first-part bit data in the data frame as uncoded bit data comprises: obtaining an amount of uncoded bit data carried in each subcarrier of the multiple subcarriers corresponding to the data frame; and calculating a sum of amounts of uncoded bit data carried in the multiple subcarriers, and using the sum as an amount of the first-part bit data in the data frame. the coded bit data and the uncoded bit data are mapped respectively onto a first portion and a second portion of bits of each subcarrier in the multiple subcarriers, and the second portion of bits is the more significant bits than the first portion of bits; wherein the determining first-part bit data in the data frame as uncoded bit data comprises: obtaining an amount of uncoded bit data carried in each subcarrier of the multiple subcarriers corresponding to the data frame; and calculating a sum of amounts of uncoded bit data carried in the multiple subcarriers, and using the sum as an amount of the first-part bit data in the data frame. obtaining an amount of uncoded bit data carried in each subcarrier of the multiple subcarriers corresponding to the data frame; and calculating a sum of amounts of uncoded bit data carried in the multiple subcarriers, and using the sum as an amount of the first-part bit data in the data frame.