Research And Implementation Of Channel Estimation Based On Two-Dimension Pilot In OFDM System

Discuss on the two-dimension pilot based OFDM channel estimation, from the view of projects application, a new implementation method for two-dimension Wiener filter is delivered based on the research of present algorithms, and the design and implementation for the channel estimation module for an actual project is also given in this paper, in which the Wiener filter is implemented using the newly delivered method. The main work in this paper includes the following aspects:First, after the wireless mobile channel characteristics and OFDM basic principle are discussed, from the three aspects of two-dimension pilot aided channel estimation, we discuss the commonly used algorithms in channel estimation module design and implementing. The commonly used interpolation method of using two cascaded one-dimension Wiener filter or linear interpolation instead of two-dimension Wiener filter is given.Second, the implementation method of two-dimension Wiener filter is discussed. Based on the method of using similar channel model to design filter, to resolve the performance reduction when SNR decreases, a improved method of implementing two-dimension Wiener filter is delivered, during which the SNR range is divided into several intervals, and the filter parameter is calculated in Matlab, thus the complex calculating in Wiener filter design when the channel estimation algorithm is running can be avoided. The performance of the channel estimation algorithm using the new-delivered filter design method is analyzed through computer simulation under different channel conditions, and the influence of different Doppler on this algorithm is also analyzed through computer simulation.Third, based on actual OFDM project, the Channel Estimation module design is discussed in details, including selecting the pilot pattern in transmitter and calculating the pilot intervals, the estimation algorithm in pilot position in receiver, and the interpolation filter design using two-dimension Wiener filter, the steps of calculating filter parameters are given in details, during which the filter design adopts the newly delivered method in this paper. The implementation of the channel estimation module on the DSP hardware platform is also given, and this implementation is successfully applied in project.