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An OFDM Adaptive Channel Estimation Method Based on Comb Pilots

A technology of adaptive channel and comb-shaped pilot, which is applied in the direction of multi-frequency code system and baseband system components, etc., can solve the problems of low complexity and achieve the effect of self-adaptive tracking and combating severe multipath fading

Inactive Publication Date: 2016-04-06
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a low-complexity OFDM adaptive channel estimation method based on comb pilots, which can perform channel estimation when the channel characteristics are unknown, and can resist severe multipath decline

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  • An OFDM Adaptive Channel Estimation Method Based on Comb Pilots
  • An OFDM Adaptive Channel Estimation Method Based on Comb Pilots
  • An OFDM Adaptive Channel Estimation Method Based on Comb Pilots

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Embodiment

[0054]A specific implementation case of the present invention in the DVB-H system is introduced below, and a simulation result diagram is given. System simulation parameters: FFT (FastFourierTransform, Fast Fourier Transform) points is 8192, CP mode is 1 / 4. The mapping mode is 16QAM, and the simulation system adopts a convolution coding with a code rate of 2 / 3. Channel parameters: Nokia handheld channel, two-path SFN channel. Table 1 is the power delay spectrum of the Nokia handheld channel. The two-path SFN channel has a 0dB echo channel.

[0055]

[0056] Table 1

[0057] Because the pilot frequency structure of the DVB-H system is not a comb pilot, but it can be converted into a comb pilot through TDI. Therefore, in order to perform a fair performance comparison with other one-dimensional interpolation algorithms, the same interpolation algorithm is used on TDI. In each simulation of this implementation case, TDI adopts CLI (CubicLagrangeInterpolation, cubic Lagrang...

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Abstract

The invention discloses an OFDM self-adaptive channel estimation method based on comb pilots. A transmitting end inserts comb interpolation pilots into each OFDM symbol and generates training pilots. The comb interpolation pilots are periodically distributed in the frequency direction, and the positions and values ​​of the training pilots and the interpolation pilots are known to the receiving end. For each OFDM symbol, the receiving end interpolates the training pilot according to the channel estimation value of the interpolation pilot, calculates its channel estimation value, and combines the channel estimation value of the training pilot obtained by direct estimation to train the tap coefficients, each OFDM After all the training pilots in the symbol are trained, the interpolation coefficient can be obtained through the tap coefficient, and then the channel estimation value of the data can be obtained according to the interpolation coefficient. The present invention is applicable to the OFDM communication system adopting comb-like interpolation pilot frequency. By adopting the training pilot frequency, the channel estimation can be carried out under the condition that the channel statistical characteristics are unknown, and the time-varying channel can be adaptively tracked and the severe multipath fading can be resisted.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and more specifically relates to an OFDM adaptive channel estimation method based on comb pilots. Background technique [0002] OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing) is a special multi-carrier modulation technology, which has natural advantages in combating multipath fading and is very suitable for high-speed data transmission. Therefore, OFDM has been widely used in modern wireless broadband access systems, such as DAB (Digital Audio Broadcasting, Digital Audio Broadcasting), DVB (Digital Video Broadcasting, Digital Television Broadcasting), LTE (Long Term Evolution, Long Term Evolution), WiFi, WiMAX (Worldwide Interoperability for Microwave Access, namely Global Microwave Interconnection Access), etc. In a wireless OFDM system, the multipath effect and the Doppler effect will cause the wireless channel to have frequency-dom...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L25/02H04L27/26
Inventor 刘光辉王福到郑承昊赵友
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA