MIMO-OFDM系统的同步算法  

Synchronization algorithm for MIMO-OFDM system

作　　者：杨春萍[1] 王键[1] 李道本[1] 

机构地区：[1]北京邮电大学信息工程学院,北京100876

出　　处：《中南大学学报（自然科学版）》2010年第2期578-584,共7页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(90604035)

摘　　要：针对MIMO-OFDM系统中对同步要求较高的问题,提出一种MIMO-OFDM系统中的时/频同步算法,该算法与其他同步算法的关键区别在于将完备广义互补正交同步码组用作同步序列。对于完备广义互补正交码组,在各分量码不重叠的情况下,具有任何相对相移的任意码以及任意码对的自相关特性和互相关特性都是理想的,这一理想特性使得时/频同步算法简单高效。该同步算法分为4步:(1)通过信号自相关实现时域上的同步;(2)通过快速傅里叶变换(FFT)实现频域上同步;(3)使用相干检测和精确时间同步实现多径分离;(4)通过相位差分算法实现精确的频偏估计。仿真结果表明:即使在低信噪比如0dB的多径快衰落信道中,MIMO-OFDM系统也可以在时域和频域上实现精确同步,同时具有高度稳定性和可靠性。Aiming at the problem of higher requirement for synchronization in MIMO-OFDM （Multiple input multiple output-orthogonal frequency devision multiplexing） system, a time/frequency synchronization algorithm in MIMO system was proposed, in which the key difference with other synchronization algorithms was to use the perfect complete generalized complementary orthogonal loosely synchronous code groups as the synchronization sequence. As regard to perfect complete generalized complementary orthogonal code groups, the cross-correlation and auto-correlation for any relative shifts between any two codes or between any code pairs were all 0 in the case of each component code that was not overlapped. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The synchronization algorithm was divided into four stages： （1） synchronization in time domain by signal autocorrelation; （2） synchronization in frequency domain by Fast Fourier Transform （FFT）; （3） multi-path dissociation using coherent detection and fine time synchronization; （4） fine frequency offset estimation by phase rotation. The simulation results show that even in the low signal noise ratio such as 0 dB multi-path fast fading channel, the MIMO system can get synchronized both in time domain and frequency domain with high stability and reliability.

关 键 词：MIMO-OFDM 同步 互补正交码码 LS码 

分 类 号：TN911.23[电子电信—通信与信息系统]