文档介绍：码分多址移动通信中扩频序列的研究
[摘要]CDMA蜂窝通信系统问世以来发展就非常迅速,已成功地应用于第二代和第三代通信系统中,其优势已成为人们的共识。扩频技术最早应用在军事领域,其发展经历了一个漫长的过程,直至目前,扩频技术仍处于不断发展的过程中。由于扩频通信系统具有抗干扰能力强,保密性能好,抗截获、抗检测能力强以及频谱密度低等特点,使得扩频码分多址在移动通信中有着广阔的应用前景。传统的扩频序列主要有:m序列、Gold序列、Walsh序列。在这些序列中,或多或少都存在一些问题:m序列具有良好的自相关和互相关特性,但码序列个数太少,不能满足组网需求;Gold序列有足够码序列个数,但复杂度不高,且存在码平衡问题;Walsh序列具有理想的同步正交特性,但在非同步时,自相关性和互相关性能急剧下降。本文就码分多址移动通信中的扩频序列进行了初步的分析和研究,给出了m序列、Gold序列及Walsh序列的形成方法,并进行了计算机仿真。
[关键字]CDMA;扩频序列;相关性;正交序列
CDMA munication among spreading sequences in the study
Abstract:CDMA munication system is very rapid development since the advent, has been essfully applied in the second and third munication system, the advantage is already became the consensus of people. The earliest application spread spectrum technology in military field, its development through a lengthy process, until now, spread spectrum technology is still in the process of continuous development. Due to the spread munication system has strong anti-interference, confidential performance is good, resistance to intercept, strong ability of testing and spectrum density low characteristic, make spread spectrum code division multiple access (cdma) in the field of munication has wide application prospects. The traditional spread spectrum sequence mainly has: m series, Gold sequence, Walsh sequence. In these sequences, and more or less all exist some problems: the m series has good autocorrelation and mutually close characteristics, but the code number of the sequence too little, and can't meet the working; Have enough Gold sequence number code sequences, plexity is not high, and there is a code balance issue; Walsh sequence has the best synchronous orthogonal properties, but in the synchronization, since the correlation and shut down sharply each other performance. This paper munication among spreading sequences of the code division multiple access (cdma) makes a preliminary analysis and research, and gives the m series, Gold sequences and the formation of Walsh sequence met