Data multiplexing method and data multiplexer, and data transmitting method and data transmitter

A method for interleaving multiplexed symbols and for transmitting a frame including slots, each of said slots holding at least a portion of the interleaved symbols, the method comprising steps of: storing the multiplexed symbols in groups in a memory, each group having F symbols, wherein F is N times a number of the slots in said frame and N is an integer larger than 1; reading out the stored symbols from the memory arid arranging the symbols read out from the memory into said slots, wherein the reading out step includes reading out a symbol from a same predetermined position in each group, and repeating the reading out step until all of the stored symbols are read out from the memory; and transmitting said slots on a physical channel.