Channel estimation and soft demodulation method for wireless optical communication OOK (On-off Keying) digital modulation

A technology of wireless optical communication and channel estimation, applied in baseband system components, multi-carrier systems, etc., can solve the problem that the receiving end does not know the CSI information and affects the system error performance, and achieves low complexity, reduced complexity, achieve easy results

Inactive Publication Date: 2012-09-12
LANZHOU UNIVERSITY OF TECHNOLOGY
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Problems solved by technology

However, in practical applications, the receiving end generally does not know the CSI information, s

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  • Channel estimation and soft demodulation method for wireless optical communication OOK (On-off Keying) digital modulation
  • Channel estimation and soft demodulation method for wireless optical communication OOK (On-off Keying) digital modulation
  • Channel estimation and soft demodulation method for wireless optical communication OOK (On-off Keying) digital modulation

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[0015] The present invention will be described in detail below with specific embodiments in conjunction with the accompanying drawings. This embodiment only shows the principle description of the present invention, and does not represent any limitation to the present invention.

[0016] The channel estimation and soft demodulation method of wireless optical communication OOK digital modulation mode of the present invention, such as figure 1 As shown in Fig. 1, the mathematical model of the atmospheric channel is first established and the noise characteristics such as turbulence that cause signal interference are analyzed. The atmospheric channel mathematical model of wireless optical communication is established in the following way: the noise generated by the flickering phenomenon of light intensity caused by atmospheric turbulence can be assumed to be multiplicative noise because its frequency is much lower than the signal frequency, and the background light noise and commun...

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Abstract

The invention discloses a channel estimation and soft demodulation method for wireless optical communication OOK (On-off Keying) digital modulation. The channel estimation and soft demodulation method for the wireless optical communication OOK digital modulation comprises the following steps of: firstly, establishing a mathematical optical wireless communications atmospheric channel model, and through a finite symbol subset of received signals, namely a data observing window and with a mean value of the received signals as a judging threshold, primarily detecting and judging OOK signal sequences received in the window and separating out received value sequences of time slots to which '0' and '1' signals belong; secondly, in order to improve the judging accuracy, counting the number of '0' and '1' symbols respectively, regulating the judging threshold, and judging secondarily; thirdly, estimating a channel noise variance according to an obtained '0' sequence and estimating intensities of the received signals according to mathematical operation between the '0' sequence and a '1' sequence; and finally, calculating a logarithmic likelihood ratio of a next bit of the OOK according to the obtained noise variance and the intensities of the received signals, and sending the likelihood ratio to a subsequent channel decoding unit.

Description

technical field [0001] The invention relates to a channel estimation method of a wireless optical communication system and a soft demodulation method realized on the basis of the method, belonging to the technical field of wireless optical communication. Background technique [0002] The wireless optical communication system uses the atmospheric channel as the transmission medium, and the turbulence phenomenon caused by the inhomogeneity of the atmosphere will cause the random fluctuation of the atmospheric refractive index. This fluctuation of the refractive index will lead to random fluctuations in the strength of the bit signal received by the receiving end, which will seriously interfere with the received signal and cause an increase in the communication bit error rate, which seriously affects the reliability and stability of wireless optical communication. . However, due to safety requirements (such as human eye safety) and mobility considerations, the transmission pow...

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Application Information

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IPC IPC(8): H04L25/02H04L27/38
Inventor 曹明华王惠琴
Owner LANZHOU UNIVERSITY OF TECHNOLOGY
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