The Theory Of OFDM And Research Of Pilot-based Dynamic Channel Estimation Algorithms

Orthogonal frequency division multiplexing (OFDM) technology is a new generation of wireless communication field is one of the most valuable technology, it has transmission speed, anti-multipath interference ability strong advantages. It increases the signal duration, effectively restrain the interference between the symbols. Channel estimation is OFDM systems to ensure the key technology to performance, first demodulation are used to estimate and tracking performance channel for the coherent detection, and then you can, so the choice of channel estimation algorithm is very important.This paper first analyzes the OFDM systems the key technologies and main advantages and disadvantages to these characteristics, says channel estimation in OFDM systems, then the important role of the channel's various decline concentration carries on the comprehensive analysis, explain channel decline will influence of channel estimation. Next the OFDM systems analysis of the working principle and structure, the model of the system of OFDM are analyzed and discussed, and the corresponding system parameter design method. Then analyzes the importance of channel estimation based on pilot .finally, and points out that the channel estimation is a kind of very good channel estimation methods, and analyses the current based on pilot. finally some typical of channel estimation algorithm.This paper proposes a method based on cosine transform (DCT) of channel estimation algorithm, presents its iterative process and to DFT algorithm based on DCT based and the simulation, and the results showed that the DCT compared by mistake bit rate and channel mean-square error are significantly lower than DFT, some (1:10) concluded that DCT algorithm of channel estimation performance very strong this conclusion.