Research On Channel Estimation Technologies In LTE Wireless System

As one of the most important standards in next generation wireless system, LTE has been widely recognized a significant status in the future communication industry, so it is valuable to research on LTE receiving technology. Channel estimation is critical in receiver of LTE system based on MIMO-OFDM structure.First, this paper discusses wireless channel, which is main challenge in wireless communication, including various kinds of fading, various kinds of extension, and afterwards wireless modeling technology. After that, we do quantitative analysis on different channel estimation criterias and algorithms, including LS algorithm, derived MMSE criteria and algorithm, and transform domain based channel estimation as well.As the emphasis of this paper, we discuss the design of channel estimator in LTE Uplink/Downlink in Chapter 4-5. A link-level modules design figure, a channel estimation module structure figure and a CE flowchart are given. Also, a group of simulation results based on 3GPP SCM MIMO channel model is listed. We propose a type of time domain interpolation method. Besides that, we apply iterative DCT channel estimation in LTE Uplink channel estimator.Here we evaluate the performance of several channel estimation technologies by simulation in different condition and modulation. LS algorithm makes the worst performance and least cost, while MMSE criterions and algorithms are opposite. These two algorithms provide valuable references in practical valid condition. While transform domain methods, like DFT & DCT, can get appropriate trade-offs between performance and cost. Besides that, the time-domain interpolation proposal, which can aquire the gain of channel estimation MSE in fast fading channel, is proved by simulation. Also, we can draw the conclusion that iterative process is a feasible method to improve the performance.