A novel method used for the performance analyzing of channel estimation in time-varying fast fading channel-equivalent channel analysis method

In a time-varying fast fading channel, due to the influence of amplitude fading and fast phase changing, the performance of QAM system was deteriorated seriously, it is also the main reason that restrains high-dimension modulation from use in fast mobile communications. In order to solve this problem, many estimation methods were presented previously. As is known, the process of channel estimation is practically that of compensation of the channel characteristic. So, in analyzing the performance of various channel estimation methods one also analyzes the equivalent channel after compensation. The characteristics of the equivalent channel after compensation is examined in the course of equivalent channel estimation. This method named the equivalent channel analysis method is introduced. By using this method, the system performance after using channel estimation is only a function of the Doppler shift and correlative coefficient of channel, and depends on the channel estimation method. We only need to calculate the correlative coefficient of two neighbouring symbol, we can obtain the relation formula between the error probability and Doppler shift using channel estimation, so it simplifies the analysis of the system performance