Multichannel modulation as a technique for transmission in radio channels

Multichannel modulation (MCM) is proposed as a technique to combat the effects of multipath fading. The multichannel transmit signal is the sum of several independent subsignals or subchannels. Each subchannel carries a low bit rate, hence helping to solve the problem of intersymbol interference (ISI). Because of the time-varying nature of radio channels, bits cannot be assigned using the water-pouring approach of information theory. For radio transmission, an equal number of bits is allocated to each subchannel. This results in unequal subchannel error probabilities. An error control coding can be applied to improve error performance. By using a longer blocklength MCM, the SNR across each block can be improved enough on all subchannels to give a desirable performance. A study on the alternative of MCM transmission for radio channels, given a statistical characterization of the fading, is presented