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Channel estimation method based on reliable decision feedback in visible light communication system

A technology of visible light communication and channel estimation, which is applied in the field of channel estimation based on reliable decision feedback, can solve the problems of occupying spectrum resources and the decrease of system spectrum utilization rate, and achieve the effect of reducing errors and improving performance

Active Publication Date: 2017-10-03
SOUTHEAST UNIV
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Problems solved by technology

For the common pilot-based channel estimation algorithm, the CSI is obtained by inserting the pilot sequence into the OFDM symbol at the transmitting end, and a large number of pilot sequences are repeatedly sent in the process of sending and transmitting data, which needs to occupy certain spectrum resources, making the system Decreased spectrum utilization

Method used

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  • Channel estimation method based on reliable decision feedback in visible light communication system
  • Channel estimation method based on reliable decision feedback in visible light communication system
  • Channel estimation method based on reliable decision feedback in visible light communication system

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Embodiment Construction

[0032] 1. Problem analysis

[0033] Such as figure 1 As shown, the system model is designed according to the DCO-OFDM system, figure 2 It is the basic block diagram of the VLC baseband system transmitter. The information received from the MAC layer reaches the baseband processing part of the FPGA through the network port module, and performs operations such as scrambling, channel coding, interleaving, constellation mapping, IFFT transformation, and CP addition on the Ethernet frame data to obtain discrete data in the time domain. Before the data enters the DAC module, it is necessary to add frame header data, namely short training sequence (Short Training Sequence, STS), long training sequence (Long Training Sequence, LTS), physical header (PHY Header) and other data, for the synchronization of the receiving end , channel estimation, etc. image 3 It is the main processing flow of the receiver of the visible light DCO-OFDM system. After the receiver data undergoes AD conv...

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Abstract

The invention discloses a channel estimation method based on reliable decision feedback in a visible light communication system. The channel estimation method based on reliable decision feedback has a high requirement for accuracy of initial channel estimation, and combines a ML (Maximum Likelihood) channel estimation algorithm with a decision feedback thought to apply in the system. High-reliability signs are used as quasi pilot frequencies of feedback, estimation accuracy is improved by secondary estimation, but the algorithm has few reliable signs in a low signal-to-noise ratio, and is not improved in performance. Aiming at the problem, the invention discloses a ML channel estimation improvement algorithm based on reliable decision feedback. In a case of different signal-to-noise ratios, different BER thresholds are set, so that a certain quasi pilot frequencies of feedback exist in the low signal-to-noise ratio, and thus, estimation performance in the low signal-to-noise ratio can be improved.

Description

technical field [0001] The present invention relates to visible light communication technology, in particular to a channel estimation method based on reliable decision feedback in a visible light communication system. Background technique [0002] The application of Orthogonal frequency division multiplexing (OFDM) in a communication system can effectively resist Inter-symbol interference (ISI). At the same time, inter-carrier interference (Inter Carrier Interference, ICI) can be further eliminated by inserting a cyclic prefix (Cyclic Prefix, CP) between symbols. [0003] Therefore, the application of OFDM technology in the VLC system can effectively resist ISI and ICI, and at the same time improve the spectrum utilization rate of the system. In the VLC system, Intensity Modulation / Direct Detection (IM / DD) is used, and the signal is transmitted with light intensity as the carrier. The modulation method used in this system is DCO-OFDM (Direct Current Optical-OFDM). [0004]...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/02H04L25/03
CPCH04L25/0204H04L25/022H04L25/0224H04L25/0242H04L25/03159H04L25/03312
Inventor 蒋良成焦晶晶陈明
Owner SOUTHEAST UNIV
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