Lte Downlink Shared Channel Estimation And Channel Of Precoding Technology Research

With the development of wireless communication technologies, the upgrade of mobile communications system is becoming faster and faster. There are just a few years from the commercial of3G technology to the introduction of LTE. LTE has a wider bandwidth, less time delay and faster data rates. Because of these features, Users will have a better experience. Depending on the promotion of the wireless operators and equipment manufacturers, LTE will be available during the next few years.PDSCH is the most important channel in the downlink of LTE physical layer. It carries most of the downlink data. Including almost all of LTE physical layer processing, the PDSCH has the most complex processes in all the downlink channels. The processing of channel estimation and pre-coding in PDSCH is the focus of this paper.This paper briefly described the physical layer protocol of the LTE system, the downlink frame structure and time-frequency resource mapping. This paper also describes every processing module in PDSCH. After this, we established a simulation platform for PDSCH. On this simulation platform, several interpolation algorithm used for LTE downlink channel estimation are compared. Based on the analysis of fading channel, this paper presents two simple methods of noise reduction. One of them is used for large time delay channel, another is for the channel in low-speed mobile environment. The simulation results shows that these two noise reduction methods have made a great improvement for the interpolation algorithm. Especially in EPA-5,6dB gain is made.This paper did a research of the important role of precoding module in PDSCH too. For the codebook-based precoding technology, the paper focuses on the pre-coding matrix selection algorithm of the UE. In this part, a selection algorithm based on channel matrix SVD decomposition and another based on minimizing noise power are present. The results show the latter eliminates the BER performance difference between the two streams of data, which is suitable for system with two streams.