Research On Bandwidth Efficient Coding And Modulation

As technology advances, people are increasingly high performance requirements ofthe communication system. Wireless channel susceptible to the influence of noise,interference and other channel factors, but also due to the dynamic changes of the user’smobile channel, these factors are still with time changes randomly. Therefore, the channelis the key to ensure the correctness of the communicaton system in the complex channelenvironments. Now there is a lot of good channel coding scheme, such as Turbo codes,LDPC codes. The spectral efficiency of binary Turbo code based on the BPSK modulationmode is not high and the traditional channel coding by increasing the redundancy toimprove error correction capability, which will inevitably cause bandwidth expansion,taking up more spectrum resources. This is not allowed clearly in the environment ofresources more valuable.1982, Ungerboeck.G proposed the idea of trellis coded modulation(TCM) in hispaper. This way consider the modulation and coding as a whole module to achieve theoptimization of communication system performance. It obtain the channel gain byimproving the equipment complexity, not by reducing the bandwidth efficiency and powerefficiency. Trellis coded modulation techniques are applicable to the additive whiteGaussian noise channel. Later scholars have proposed that the bit-interleaved codedmodulation(BICM), the performance of the coded modulation schemes performance inRayleigh fading channel better than trellis coded modulation.In this paper, we proposed the Turbo-TCM coded modulation scheme by combiningthe Turbo code and Trellis Coded Modulation based on the above-mentioned mature. Onthis basis, we prosed the Turbo-MTCM coded modulation scheme, to enhance theperformance of the traditional Turbo-TCM coded modulation schemes in additive whiteGaussian noise channel. In the chapter4, we have combined the based on iterativedecoding of BICM and Turbo codes to form Turbo-BICM-ID coded modulation scheme.Meanwhile, we use double Binary Turbo code to instead of the traditional convolutionalcode encoder, to enhance the tradition of BICM-ID coded modulation schemes’sperformance under Rayleigh fading channel.