Precoding and drive current joint optimization method for four-color visible light communication system

Abstract

The invention discloses a precoding and drive current joint optimization method for a four-color visible light communication system, which aims at minimizing sum mean square error (MSE) of signal estimation in a corresponding light channel while lighting quality requirements are met. Compared with the existing three-color visible light communication precoding matrix optimization problem, the four-color visible light communication system adds a light communication wavelength division multiplexing channel, and an ability of adjusting indoor lighting quality is also provided. In view of the optimization problem, nonlinear color rendering index constraints are firstly converted into linear light mixing ratio constraints via linear light mixing equations, and optimization solution is carried out on the MSE minimal value through introducing semidefinite relaxation algorithm.

Description

technical field [0001] The invention belongs to the technical field of wireless optical communication, and in particular relates to a joint optimization method of precoding and driving current for a four-color visible light communication system. Background technique [0002] Due to the low cost, long life and high efficacy of LEDs, LEDs are rapidly occupying a dominant position in today's lighting market, replacing traditional lighting equipment. At the same time, the fast switching capability of LEDs also makes it possible to transmit broadband signals through light, and finally realizes indoor visible light communication (VLC). Although high-speed VLC systems using phosphor-excited white LEDs have been realized, the limited modulation bandwidth of LEDs remains a bottleneck for the continued development of VLCs. Therefore, the application of optical multiple-input multiple-output (OMIMO) has become an important factor to continue to improve the performance of VLC in the fu...

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Problems solved by technology

[0006] When the number of color lights exceeds 3, considering the color rendering index (CRI) constraint, it is a big challenge to introduce very complex nonlinear CRI constraints into the joint optimization problem of precoding matrix and bias current

Existing work only discusses the optimization of the RGB three-color LED communication system, and when the color temperature CT is specified, the color rendering index cannot be adjusted, which cannot well meet the needs of indoor lighting

[0007] In addition, most of the existing work only considers the optimization of the precoding matrix and bias current when the number of data streams is equal to the number of actual physical channels.

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