Phase shift coding method based on pulse amplitude modulation system and implementing device

Abstract

The invention belongs to the technical field of visible light communication, and particularly relates to a phase shift coding method based on a direct-modulation direct-detection pulse amplitude modulation system and an implementing device. At a system transmitting end, a phase shift coding method opposite in symbol is adopted for odd-even code elements of a continuous symbol sequence; at a system receiving end, a differential decoding method of delayed subtraction is performed on adjacent symbols receiving the code elements. In the implementing device, a transmitting end comprises a phase shift coder, a PAM (pulse amplitude modulation) mapping module, a serial-to-parallel / parallel-to-serial conversion module, an up-sampling module, an LED and a driving module of the LED; a receiving end comprises a differential decoder, a serial-to-parallel conversion module, a rear balance module, a PAM de-mapping module, a clock synchronizing module, a normalization module, a down-sampling module, a focusing lens, a light filter and a receiver. By using the implementing device and the coding and decoding method, crosstalk noise between inherent direct-current component and signal in a visible light communication system based on a pulse amplitude modulation format can be effectively eliminated, sensitivity of the receiver can be improved, signal transmission quality can be improved, and system performance can be improved effectively. The method is simple to implement and easy in integration.

Description

technical field [0001] The invention belongs to the technical field of visible light communication, and in particular relates to a phase shift (PS) encoding method and an implementation device based on a pulse amplitude modulation (PAM) system. Background technique [0002] At present, white light emitting diodes (LED, light emitting diode) have been widely used in various fields, such as lighting, signal emission, display and so on. Compared with other commonly used light sources such as incandescent lamps and fluorescent lamps, white LEDs have a higher modulation bandwidth. In addition, white LEDs also have many advantages such as good modulation performance and high response sensitivity. Using these characteristics of LED, we can modulate the signal to the light emitted by LED for transmission, so as to realize the effective integration of lighting and communication. Visible light communication (VLC, Visible Light Communication) is a new green information technology tha...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a phase-shift encoding method and implementation device based on direct modulation and direct detection pulse amplitude modulation (PAM) system, which is used to realize visible light high-speed communication based on PAM modulation, and solve the problem of receiving signals in existing PAM modulation technology. Crosstalk noise affects serious problems, thereby improving the transmission performance of the system

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