Mimo-ofdm System Channel Estimation Study

With the rapid development of mobile multimedia communication services, spectral efficiency and multipath fading is becoming increasingly stretched. In order to overcome these two problems, this paper introduces the MIMO-OFDM Systems. In mobile communication systems, it presented an enormous challenge in pointing against restoring the original data, and improving communication quality on the receiving end, because of much randomness and unpredictability of wireless channel , and the introduction of channel estimation effective solution to these problem. However, the traditional channel estimation algorithm has high complexity, low estimation accuracy problem and so on, for the problem ,this paper has simplified and improved several traditional channel estimation algorithm.This paper introduces the MIMO-OFDM system theory and system architecture firstly, and gives the more common non-blind channel estimation algorithm that is based on pilot or training sequence based channel estimation which based on the structure of this systems。Which, the LS of training sequence channel estimation algorithm requires a large number of matrix inversion, so this paper has simplified the algorithm to make it not only reduces the computational cost ,but also enhance performance of the algorithm, and then simulated by MATLAB was verified. Finally, the subspace-based blind channel estimation has been investigated, give a signal channel model and offer a subspace-based blind channel estimation arithmetic. This arithmetic is based on decomposition of the subspace, and uses the orthogonality of the signal subspace and noise subspace to separate them. What's more we get the estimation results of the other sub-carrier wave By zero-filling interpolation technology. In this process the tunnel statistic information is needless.Simulation results show that the method has a faster convergence rate and better estimation performance.