A demultiplexer for channel interleaving in communications systems with multiple carriers and/or transmitter diversity includes a distribution module that distributes data bits in succession to successive transmitter antennas, and a switching module coupled to the distribution module. The distribution module routes one data bit to each antenna such that no data bit is routed to the same antenna as the previous data bit. The switching module controls the distribution module to skip an antenna in the routing process once each time a predefined number of data bits have been routed. Alternatively, the switching module may control the distribution module to repeat an antenna in the routing process once each time a predefined number of data bits have been routed. The transmitter antennas may, in the alternative, be different carrier frequency bands.