Method and device for channel estimation of terminal in time division synchronous code division multiple access system

Abstract

The invention provides a method and a device for channel estimation of a terminal in a time division synchronous code division multiple access system. The system comprises the following steps: determining a Midamble code for calculating a channel estimation post-processing noise threshold; removing reconstructed signals of each cell from data received_midamble in the Midamble code to obtain relative clean data received_midamble_net of which the reconstructed signals of all cells are removed; obtaining the channel estimation post-processing threshold by the data received_midamble_net and the determined Midamble code; and calculating channel estimation values of each cell according to the data received_midamble, the Midamble code of each cell and the obtained channel estimation post-processing threshold. The method and the device improve the accuracy of the channel estimation of the terminal in an environment of same frequency interference so as to improve the demodulation performance of the terminal.

Description

technical field [0001] The present invention relates to the field of communication technology, in particular to a method and device for terminal channel estimation in a TD-SCDMA (Time Division Synchronous Code Division Multiple Access, Time Division Synchronous Code Division Multiple Access) system. Background technique [0002] In the existing TD-SCDMA system, in order to improve spectrum utilization, co-frequency networking has become an effective solution. However, co-frequency networking also brings co-channel interference while improving spectrum utilization. Co-channel interference refers to the interference between users in different cells caused by adjacent co-frequency cells using the same carrier frequency for data transmission. Co-channel interference will degrade system performance. [0003] In the case of inter-frequency networking, the signals of adjacent cells are at different frequency points, which can be treated as out-of-band noise. Only the interference o...

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Problems solved by technology

[0006] (1) The threshold is calculated based on the maximum value of the channel estimation tap. Usually, the maximum value is multiplied by a coefficient less than 1, and the result is used as the threshold. The advantage of this method is that it is simple, but if the threshold coefficient is set small, the signal-to-noise ratio is not high If the threshold coefficient is set too high, when the signal main path is strong, the weaker path will be judged as noise, resulting in the degradation of terminal demodulation performance in a multipath environment;

[0007] (2) Calculating the threshold based on the noise, usually by multiplying the mean value of the noise by a coefficient greater than 1, and the result is used as the threshold, but the judgment of the noise itself also needs a certain basis, usually based on the threshold in (1) to judge the noise, if The threshold in (1) is unreasonable, and the calculation of noise is inaccurate, resulting in an unsatisfactory setting value of the noise threshold, especially in a multipath environment with strong co-channel interference, which will greatly affect the demodulation performance of the terminal

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