Turbo joint source-channel coding of non-uniform memoryless sources in the bandwidth-limited regime

This letter proposes a novel one-layer coding/ shaping scheme with single-level codes and sigma-mapping for the bandwidth-limited regime. Specifically, we consider nonuniform memoryless sources sent over AWGN channels. At the transmitter, binary data are encoded by a Turbo code composed of two identical RSC (Recursive Systematic Convolutional) encoders. The encoded bits are randomly interleaved and modulated before entering the sigma-mapper. The modulation employed in this system follows the unequal energy allocation scheme first introduced in [1]. The receiver consists of an iterative demapping/decoding algorithm, which incorporates the a priori probabilities of the source symbols. To the authors knowledge, work in this area has only been done for the power-limited regime. In particular, the authors in [2] proposed a scheme based on a Turbo code with RSC encoders and unequal energy allocation. Therefore, it is reasonable to compare the performance with respect to the Shannon limit of our proposed bandwidthlimited regime scheme with this former power-limited regime scheme. Simulation results show that our performance is as good or slightly better than that of the system in [2].