卫星调制解调器E1接口设计及信道编译码技术研究

【作者】 吴清兰；

【导师】 张忠培；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2009， 硕士

【摘要】 卫星通信自问世以来,就不断面临竞争和挑战。但是由于它独特的优势,卫星通信已成为国家信息基础设施不可缺少的组成部分。其中,调制解调器技术是一个非常重要的方面。E1是我国和欧洲使用的电信网一次群传输标准,主要提供2M的话音通信服务。由于其悠久的历史和良好的性能,在世界范围内已经有非常丰富的E1信道资源。为了支持电信网的数据传输,在几乎所有的卫星调制解调器产品中,都提供有符合G.703标准的E1数据接口。E1技术虽然已经很成熟,但是为卫星调制解调器设备提供E1数据接口却非常有实际应用上的需求。另外,卫星信道环境复杂,具有较高的信道误码率及信号衰落特性,为了使通信的误比特率尽量的低,除了选择合适的调制/解调方式以外,还应采用性能良好的信道编译码技术。因此,先进的差错编码处理技术是卫星调制解调器的一个主攻方向。在几乎所有的卫星调制解调器产品中,都提供有卷积码、Turbo乘积码等多种编码方式。这些码有比较好的性能,但是也有一定的不足。不断研究实现性能优异的新的编译码方案,是非常有前景的。本文针对上述问题,以E1和信道编译码为研究对象,主要设计了卫星调制解调器的E1接口,对E1网络数据进行了提取插入处理,并仿真验证了一种新的分组卷积码--LTC码的优异性能。本文的主要内容有:(1)研究了E1网络的基本知识,包括网络起源、优势和帧结构等。(2)通过配置E1单片收发器DS21354的寄存器和引脚,设计实现了E1数据接口,包括数据的编解码、成帧、同步等操作。(3)基于FPGA实现了E1数据的提取插入功能,实现了数据速率的可调节。(4)利用Matlab仿真了LTC码的优异性能,并将其与相对应的SCCC码和Turbo码进行了比较,突出了LTC的性能优势。接着,又仿真比较了分组长度对LTC码性能的影响。更多还原

【Abstract】 Satellite communication has become more and more important because of its particular advantages. And satellite modem is one of the most important fields.As the base group standard of telecommunication network in China and Europe, E1 network is widely and maturely used. Because of its early use and good reliability, there are full of E1 channel resources all over the world now. Almost all satellite modem equipments support E1 data access. Designing an E1 data interface for a satellite modem is a common and a must. It is of great sense in real life applications.The environment of satellite communication is more complex than that of other communications. In order to decrease the bit error rate and supply good communication quality, FEC strategies are very important. So supplying more outstanding FEC technology is one of the most important developing directions. Among the exiting satellite modems, FEC strategies such as convolutional codes and TPCs are very common, which are not no perfect. Reseach of new and better FEC strategies is useful.Based on the above problems, here, E1 interface design and data“drop&insert”function are researched, as well as advantage performance of a kind of new code-laminated turbo codes (LTC). The following are the main contents of this paper:(1) Study the main concepts of E1 network.(2) Design E1 interface by writing the registers of the E1 SCT DS21354 and configuring the corresponding pins.(3) Supply“drop&insert”function with FPGA, and the data rate can be chosen outside to fix particular data rate requirements.(4) Simulate with Matlab to achieve and verify the outstanding performance of LTC by comparing to its related Turbo codes and SCCC codes. Later, the impact of blocks length N is researched, too.更多还原