Td-scdma Research On Channel Estimation And Its Application

In this thesis, the problems of channel estimation and joint detection for TD-SCDMA mobile communication systems are investigated. We mainly investigate cyclic correlator and conjugate gradient (CG) algorithm are investigated mainly and applied in joint detection.According to the Jakes simulation model of fading multi-channel, a channel estimation method based on cyclic correlator from maximum likelihood estimation is obtained. We apply conjugate gradient algorithm in the optimal theory to channel estimation and obtain the iterative algorithm of channel estimation. In iteration, FFT is used to calculate multiplication between matrix and vector for reducing computation complexity. Two channel estimation methods are simulated in fading multi-channel. At last, the simulation results of two channel estimation are applied to joint detection that can eliminate ISI and MAI at the same time.The simulation results indicate that the performance of CG algorithm is better than that of cyclic correlator. It is because that the channel estimation of CG algorithm is more accurate in noise. But when SNR is larger, the performance of two channel estimation is approximate. So cyclic correlator is also an applied channel estimation method because cyclic correlator have simple structure and small computation complexity.