A communication apparatus for communicating data conveyed by a plurality of transport channels, the data of the transport channels being multiplexed into at least one multiplexing frame, includes a processing unit. The processing unit transforms an input data block of an initial size into an output data block of a final size in accordance with a rate matching ratio of the final size to the initial size, transmits information on a maximum payload of the at least one multiplexing frame the communication apparatus can send, receives a first parameter relative to the rate matching ratio, and calculates the final size, according to the initial size of the input data block, the first parameter, a second parameter and the maximum payload of the at least one multiplexing frame. The second parameter is representative of a maximum puncture rate and is a predefined parameter for calculating the final size.