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DCO-OFMD direct current bias and power joint optimization method under non-flat channel

A DC bias and joint optimization technology, applied in the field of visible light communication, can solve problems such as wasting energy and signal distortion

Active Publication Date: 2015-12-02
SOUTHEAST UNIV
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Problems solved by technology

Too much DC bias wastes energy; too little can severely distort the signal

Method used

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  • DCO-OFMD direct current bias and power joint optimization method under non-flat channel
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  • DCO-OFMD direct current bias and power joint optimization method under non-flat channel

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Embodiment Construction

[0040] In order to understand the technical content of the present invention more clearly, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0041] figure 1 is a transmitter block diagram of the DCO-OFDM system in the embodiment of the present invention, such as figure 1 As shown, the working process of the DCO-OFDM transmitter is as follows: The DCO-OFDM system has a total of 2K subcarriers, and each subcarrier is modulated and power allocated to obtain the symbol S k , with power p on each subcarrier k =E[|S k | 2 ]. Since optical communication requires the output signal to be a real number, the signal needs to satisfy and S 0 = S K =0. because The resulting symmetry only considers the power of subcarriers k=1,...,K−1. The time-domain signal s is obtained by inverse fast discrete Fourier transform (IFFT). n . Then in the time domain signal s n Overlay size is B dc The DC component of s ...

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Abstract

The invention discloses a direct current bias and sub-carrier power joint optimization method of a visible light communication DCO-OFMD system under a non-flat channel. The object of the optimal design is to maximize system data rate by adjusting the direct current bias and the sub-carrier power under certain luminous power limitation or electric power limitation. The method comprises the steps as follows: (1) initializing relative parameters such as a channel parameter, a limitation condition, an initial sub-carrier power distribution, and so on; (2) fixing the sub-carrier power distribution, and optimizing direct current bias size and effective power; (3) fixing the direct current bias size and the effective power, and optimizing the sub-carrier power; (4) repeatedly executing the steps (2) and (3) until there is a convergence, and outputting the final direct current bias size and the sub-carrier power. The method of the invention could accurately obtain the optimal direct current bias size and a sub-carrier power distribution solution under a plurality of conditions such as luminous power limitation, electric power limitation, and so on, and the optimization method is fast in rate of convergence, easy to realize and high in result precision.

Description

technical field [0001] The present invention relates to the field of visible light communication, in particular to a method for joint optimization of DC bias and subcarrier power in a DCO-OFDM (Direct-Current-Biased Optical Orthogonal Frequency Division Multiplexing) communication system under a general non-flat visible light channel. Background technique [0002] Visible light communication (VLC) is an emerging access technology that takes into account both lighting and communication, and can meet high-speed data services. It has many advantages including low cost, green safety, good confidentiality, easy implementation, and good electromagnetic compatibility. . Different from traditional radio frequency wireless communication, visible light communication uses intensity modulation direct detection (IM / DD), that is, the transmitter uses the light intensity to represent the signal amplitude, and the receiver detects the light intensity to receive the signal. The transmitting...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L5/00H04L27/26
CPCH04L5/006H04L27/2626
Inventor 王家恒凌昕彤梁霄赵春明
Owner SOUTHEAST UNIV
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