Multi-carrier transmission system utilizing channels with different error rates

摘要

A communication system for transmitting data comprising first and second data streams on a communication link having a communication channel of fixed bandwidth. The first and second data streams have first and second error tolerances, respectively, the first error tolerance being greater than the second error tolerance. The communication system includes a transmitter and a receiver, the transmitter transmitting data on the communication link for receipt by the receiver. The transmitter includes circuitry for dividing the communication channel into a plurality of sub-bands. In the preferred embodiment of the present invention, each sub-band has a bandwidth chosen such that distortions introduced by the communication link in the sub-band may be represented by an attenuation coefficient and phase shift. The present invention generates a signal which is the sum of a plurality of carriers, one per sub-band, in which the amplitude of carrier in the sum signal is determined by a symbol set having a plurality of symbols. A portion of the data is transmitted in each of the sub-bands by selecting symbols from the symbol set associated with that sub-band. The number of symbols in the symbol set is chosen to provide an error rate for data transmitted in the sub-band, the error rate for a first one of the sub- bands being greater than the error rate for a second one of the sub- bands.