随着物联网的快速发展和低功耗移动设备的密集部署，基于多中继的无线通信技术受到了学术界的广泛关注。实现可靠高效的数据传输是多中继系统的一个重要设计目标。虽然信道编码和扩频调制可显著改善无线通信的数据传输质量，但如何在多中继系统中设计优秀的编码与扩频调制方案仍是一个极具挑战性的问题。. 本项目拟在多径衰落信道中对多中继系统的原模图码、混沌扩频调制及其相关技术展开深入研究：1）开发高效的编码协作协议和基于格雷映射的M元差分混沌键控，并推导多中继协作系统的性能极限；2）完善原模图码的外信息转移函数理论，分析其渐近收敛与纠错性能；3）优化M元差分混沌键控的信号结构，设计低复杂度的分层准循环原模图码，获得靠近系统极限的性能；4）提出全新的Turbo迭代检测算法和基于动态调度机制的联合信度传播译码算法，以提升系统的整体性能。相关研究成果可为新一代无线通信应用提供一种更可靠更高效的数据传输方案。

With the rapid development of internet of things (IoT) and dense deployment of low-power mobile devices, the multi-relay-based wireless-communication techniques have drawn a great deal of attention from the academic community. Realizing reliable and efficient data transmission is a critical design objective of multi-relay systems. Although channel coding and spread-spectrum (SS) modulation can be utilized to significantly improve the quality of data transmission in wireless-communication scenarios, how to design excellent coding and SS modulation schemes for multi-relay systems is still a very challenging problem.. To address the aforementioned problem, this project plans to conduct an in-depth research on the design of protograph codes, chaos-based SS modulation, and their related techniques for multi-relay systems over multipath fading channels. To be specific, 1）we develop several efficient coded cooperative protocols as well as a Gray-mapped M-ary differential-chaos-shift-keying (DCSK) modulation, and derive their corresponding performance limits；2）we extend the theory of protograph extrinsic-information-transfer (PEXIT) function and analyze the asymptotic convergence and error performance of protograph codes；3）we optimize the structure of M-ary DCSK signal and design a family of multi-layer quasi-cyclic (QC) protograph codes to achieve fundamental-limit-approaching performance；4）we propose a new Turbo iterative detection algorithm and a dynamic-scheduling-mechanism-based joint belief-propagation (BP) decoding algorithm to boost the overall system performance. The expected results of this project can offer a more reliable and efficient data-transmission scheme for the next-generation wireless-communication applications.