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Channel estimation method used in amplitude limiting OFDM system

A channel estimation and amplitude limiting technology, which is applied in the field of channel estimation of the amplitude limiting OFDM system, can solve the problem that the estimation algorithm cannot converge quickly, and achieve the effect of strong resistance to Doppler frequency shift and fast convergence speed.

Inactive Publication Date: 2012-02-29
SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide an iterative channel estimation method suitable for a limited OFDM system, and to solve the problem that the existing channel estimation algorithm in the OFDM system with comb pilot distribution cannot converge quickly

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  • Channel estimation method used in amplitude limiting OFDM system
  • Channel estimation method used in amplitude limiting OFDM system
  • Channel estimation method used in amplitude limiting OFDM system

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Embodiment Construction

[0045]Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0046] 1. Signal processing method at the sending end

[0047] 1) Signal clipping. The peak-average value of the OFDM time-domain signal after IFFT transformation is relatively large, and it needs to be limited and filtered at the sending end, as shown in the following formula:

[0048] x g ( n ) = g ( ...

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Abstract

The invention relates to a channel estimation method used in an amplitude limiting OFDM system. In the method, pilot frequency information and history channel information are comprehensively used so as to acquire current channel response and improve a convergence speed of an iterative algorithm. Firstly, amplitude compensation is performed to a receiving signal. Then through a LS or MMSE algorithm, the pilot frequency channel information can be acquired and the channel estimations of all subchannels can be interpolated. Weighted average is performed to the channel estimations and the history channel information so as to acquire the response of the current channel. Then the response is applied for equalizing channel fading. An acquired symbol through decision is gone through amplitude limiting filtering so as to estimate nonlinear noise information. And the noise information is used for reestimation of the channel and signal detection. The method is suitable for a time-varying channel environment. Error diffusion can be avoided. Simultaneously, a disadvantage of the slow convergence speed by using the original method can be overcome.

Description

technical field [0001] The invention belongs to the technical field of communication, in particular to a channel estimation method for a limited OFDM system. Background technique [0002] Multimedia Sensor Network (WMSN) is a new type of information acquisition and processing technology. Compared with the traditional sensor network (WSN), it pays more attention to the collection, processing and transmission of audio, video, image and other large data and large information media. Therefore, the data transmission method with low energy consumption and high speed has become one of the key technical issues restricting its development. As an efficient and widely used data transmission method, OFDM is suitable for multimedia sensor networks. The OFDM time-domain signal is formed by the superposition of multiple independent modulated sub-signals, which may produce a large peak-to-average ratio (PAPR). However, when a signal with a large peak-to-average ratio passes through the n...

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Application Information

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IPC IPC(8): H04L25/02H04L27/26
Inventor 解永生周磊磊汪明亮付耀先
Owner SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI
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