The researching work of this thesis is mainly about the encoding and decoding schemes of the arrayed waveguide gratings and the bragg fiber gratings systems . firstly , the basic principle , system schemes and the key technologies are introduced in section one . the development , research status and trends of ocdma technologies are also summarized 本论文的第一章对ocdma系统进行了较为全面的综述,对光码分多址技术的基本原理和分类、编解码结构方案以及关键技术进行了介绍,并对光码分多址技术的发展和现状进行了概述。
Due to the advantages of ldpc codes , their applications in reliable communications have received great interests and have become one of most attractive field in channel coding community . now , the application of ldpc has been put on the agenda . this thesis investigates some aspects of ldpc codes with emphasis on message passing algorithms and quantization decoding schemes of ldpc codes 由于低密度校验码具有诸多优点,它在信息可靠传输中的良好应用前景已经引起学术界和it业界的高度重视,成为当今信道编码领域最受瞩目的研究热点之一,低密度校验码的应用也已经被提到日程上。