Method of channel estimation through multiple OFDM (Orthogonal frequency Division Multiplexing) symbols

Abstract

The invention relates to the field of mobile communication technologies, in particular to a method of carrying out channel estimation through combining multiple OFDM (Orthogonal frequency Division Multiplexing) symbols. The method comprises the following steps of establishing a frequency domain receiving vector expression, utilizing MCE-BEM (Modified Complex Exponential-Basis Expansion Model) to carry out time domain modelling and deducing to obtain a frequency domain receiving expression, deducting a pilot frequency observation equation of each of M OFDM symbols, and utilizing an LS (Least Squares) rule to obtain a belt estimation parameter and a simultaneous equation so as to determine a time domain channel matrix. According to the method provided by the invention, M OFDM symbols form one symbol block to carry out channel estimation, firstly, the time domain modelling is carried out to obtain an expression of a time domain channel to complete deduction of the pilot frequency observation equation of each of M OFDM symbols, secondly, the belt estimation parameter is estimated by adopting an LS estimation manner, and lastly, the time domain channel matrix is obtained to complete estimation. Multiple symbols only carry out approximation of dimensionality of a base model at one time after rounding up to an integer, so that the modelling error is smaller, the number of parameters to be estimated is reduced, and the estimation performance is improved under the same pilot frequency number.

Description

technical field [0001] The invention relates to the technical field of mobile communication, in particular to a method for jointly performing channel estimation on a plurality of OFDM symbols under a time-varying channel. Background technique [0002] The Doppler effect brought about by high-speed movement will seriously reduce the performance of the mobile communication system, resulting in the destruction of the orthogonality between the subcarriers of the Orthogonal Frequency Division Multiplexing (OFDM) system, resulting in subcarriers. Inter Carrier Interference (ICI): Channel estimation is an important part of the front end of the receiver. If the channel information can be accurately estimated, ICI can be suppressed. However, the fast time-varying nature of the channel makes it necessary to acquire channel information Re-discuss in depth. [0003] In high-speed railway wireless communication, the time-varying channel is usually estimated through the equivalent modeli...

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Problems solved by technology

[0002] The Doppler effect brought about by high-speed movement will seriously reduce the performance of the mobile communication system, resulting in the destruction of the orthogonality between the subcarriers of the Orthogonal Frequency Division Multiplexing (OFDM) system, resulting in subcarriers. Inter Carrier Interference (ICI): Channel estimation is an important part of the front end of the receiver. If the channel information can be accurately estimated, ICI can be suppressed. However, the fast time-varying nature of the channel makes it necessary to acquire channel information Re-discuss

[0003] In high-speed railway wireless communication, the time-varying channel is usually estimated through the equivalent modeling of the base extension model. At present, the channel estimation of the OFDM system with comb pilot structure is based on a single symbol, but when the speed of the mobile terminal decreases In the case of , the time variation of the channel within a single symbol is not particularly obvious. At this time, the base extension model is selected to approximate the channel. Compared with the traditional linear model, the performance improvement is limited, especially when the normalized maximum Doppler frequency shift of the channel is slightly greater than 0.1 Time

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