Bandwidth-efficient transmission using nonbinary CRSC turbo codes

Since power and bandwidth are limited resources in modern digital communications systems, the subject of this paper is the design of nonbinary circular recursive systematic convolutional (CRSC) turbo codes combined with high level modulation, such as 8PSK modulation. It includes how to choose and/or design the components in a turbo encoder, as well as the design of the interleaver and the puncturer, to get the best possible performance with simplified Max-Log-MAP algorithm and higher transmission rate. Several combination schemes of coding and modulation, and their complexity are discussed. A comprehensive study over AWGN channel is carried out to show the performance of the proposed coding schemes and their potential as an alternative for more effective and efficient transmission of data via satellites without increasing the required bandwidth.