This paper described a novel combination of OFDM with a standard convolutional code and an interleaver optimized for channels with narrowband and impulsive noise. The optimum interleaver efficiently separates error bursts that occur in the time and in the frequency domain. It can be characterized as a generalized block interleaver whose operation can be described intuitively. This design was implemented successfully in a medium voltage powerline carrier communication system.

A novel digital modulation scheme is proposed that uses coding to reduce the bandwidth of a signal. The schematic diagram of the transmitter is presented, and optimisation criteria are given and applied to the transmitter. The resulting new modulation schemes are described and compared with traditional schemes. Compared to uncoded M-ary quadrature amplitude modulation, the new modulation schemes allow an increase in the data rate by up to 0.5 bit/s/Hz for a given performance, or to reduce the signal power by about 1 dB for a given data rate.>