8PSK+TCM编码调制解调技术

【作者】 王静；

【导师】 蔡征宇； 唐彦波；

【作者基本信息】 南京理工大学 ， 电子与通信工程， 2012， 硕士

【摘要】 近年来,通信技术随着人们的需求得到了飞速的发展,人们对通信系统的要求也越来越高,大的容量是系统首先应具备的,频率利用率和通信质量的保证也是不可忽视的。通信技术的不断发展也使得频带资源日益缺乏,如何在有限的频带上完成高质量的通信一直是人们追求的目标。因此,作为解决这一问题的方法之一,TCM编码调制解调技术被提了出来。本文研究了网格编码调制与解调技术,这种技术是建立在Ungerboeck提出的子集划分的方法的基础上的,不需要改变原来的传输速率和带宽,获得的编码增益十分可观,约为3-6dB。TCM+8PSK的解调方法通常是Viterbi译码。数据在经过高斯噪声信道后经过维特比译码可以大大减小判别时候的误码率,数年来,这门技术发展得很快,逐渐取代很多其他的方法,而在各个领域得到扩展和延伸,例如多用户检测领域和卫星通信领域等。本文给出了一种基于FPGA的网格编码调制解调技术的实现方式,这种技术解决了通信系统中高速传输数据所面临的频带资源受限的问题。将编码和调制有机结合在一起,以4状态编码方式为基础,解决了将编码和8PSK单独使用所带来的弊端,以保证数据在复杂信道中的传输质量。在解调信号时,研究了基于欧氏距离的维特比译码,是在卷积编码的维特比译码方法的基础上做了些改进。值得注意的是传统的维特比译码比较的是汉明距离,且网格图表示的状态是码组。但是本课题所使用的维特比译码比较的是欧氏距离,且网格图表示的是波形。本文在充分研究了TCM原理的基础上,通过matlab和FPGA来分别实现了AWGN信道下TCM信号的产生和解调。更多还原

【Abstract】 For the past few years, with the requirement of the population, the technology of the communication has advanced with exceptional speed. First, the communication system should have the high capacity. Secondly, the operating factor of the frequency and the quality of the communication should not be ignored. With the development of the communication, we are short of the bandwidth resources. How to accomplish the communication of high quality is the goal we are always pursuing. So as one of the methods to solve the questions, TCM technology is proposed.In this dissertation, the Trellis Coded Modulation and Demodulation technology is described. This technology is based on the method of partition in subclass brought by Ungerboeck. It can achieve a power gain of 3-6dB in the case that the transmission bandwidth and speed are not be changed. The method of demodulation of TCM+8PSK is Viterbi decoding. When the signal get through from the white Gaussian noise channel, it will be decoded with less errors by the method of Viterbi decoding. In the latest years, this technology has been developed quickly and it can be applicable in a lot of kinds of domains instead of other technologies. For example, it can be applicable in satellite communication, speech recognition systems and multiuser detection.This paper describes the implement method of TCM based on FPGA. It can solve the question of the limited frequency bandwidth when data is transported at a high speed. The encoding is combined to 8PSK technology to avoid the weakness of one separate technology. The aim is to make sure the communication quality in the complex channel. Besides, the paper proposes the Viterbi decoding based on Euclidean distance, which is an improved method. It is worth noting that the traditional one is focused on comparing the hamming distance while the method in this paper compares the Euclid distance, and the state in the grid pattern indicates the waveform. This paper describes the principal of the Trellis Coded Modulation at first. Then matlab and FPGA is used to complete the generation and the demodulation of the TCM signal.更多还原