Research Of Channel Estimation Technology In Mimo Mc-cdma System

The recent years witnessed the appearance of an advanced system in modern telecommunications, MIMO MC-CDMA, a technologically advantageous combination of multiple-input multiple-output (MIMO) technology and multi-carrier code division multiple access (MC-CDMA) technology. Owing to its large channel capacity, high transfer rate, strong resistance to multipath interference, and high spectral efficiency, MIMO MC-CDMA has become one of the most researched fields in mobile communication technology. Most importantly, in the research of the MIMO MC-CDMA technology, channel estimation provides accurate channel state information for space-time decoding and coherent demodulation. This paper focuses on the pilot-aided channel estimation technology in the MIMO MC-CDMA system.The research is undertaken respectively in the environment of slow fading channel and fast fading channel.First, with regard to the traditional pilot environment-performance irrationality in the slow fading channel, a sliding-selected pilot distribution block is designed which is not only resource-saving but also applicable to the multi-antenna MC-CDMA system. By reducing the mass matrix to unit matrix and the number of matrix dimension, the correlated complexity of channel estimation algorithm has decreased as well. Simulation results and analyses show that the system performance can be promoted to some extent by the rational pilot design doubled with an improved algorithm and a suitable primary multipath component under a different SNR.Second, with regard to the conventional optimal pilot distribution feature and high PAR in the slow fading channel, the research designs an unequal interval and unequal energy F-C two-dimensional orthogonal optimal pilot. Furthermore, the research proposes a Lagrange interpolating algorithm for channel frequency response estimation according to the new pilot structure and the Lagrange polynomial fitting principle. Simulation results and analyses show that the algorithm can approach the optimal performance of the LS channel estimator at a lower computational complexity.Finally, according to the features of fast fading channel the research proposed a time-varying channel linear model and a current signal based channel estimation algorithm, which solved the low real-timing problem due to a signal delay in the before and after signal based channel estimation algorithm. Simulation results and analyses show that the improved algorithm outperforms the before and after signal based channel estimation algorithm under a certain SNR.This research focuses on the MIMO MC-CDMA system channel estimation in the light of decreasing the computational complexity and increasing estimation accuracy. Pilots designed in different channels and improved algorithms to some extent improved the performance of the MIMO MC-CDMA channel estimation and brought bright future in the engineering implement.