Abstract: A novel turbo-DFH-coded modulation method is proposed,which combines turbo coding with the differental frequency hopping(DFH) technology.The turbo-DFH encoder consists of two frequency transition functions parrallely concatenated via a random interleaver.An iterative structure is adopted to decode the codes at the decoder.A modified Log-MAP algorithm is presented,that is used to compute the soft output of the component decoders.Simulation results showed that as the ideas of random coding and iterative decoding are used,the bit error rate performance of the turbo-DFH system is significantly better than that of the DFH system with the conventional error correction code and missed hop correction algorithm.