In a communication method, data from a plurality of channels is combined into a composite channel by writing data from the plurality of channels as one-bit symbols to a memory, and reading out the data from memory to form the composite channel. The combining of radio frames from the channels forms a coded composite transport channel for transmitting the data in the downlink. To form the coded composite transport channel, an input process is initiated to write data for each radio frame of a transport channel as one bit symbols to a memory of an interleaver. On an output side of the interleaver, an output process to read out the data stored in the memory is performed to form the coded composite transport channel.