Generalized mixed visible light modulation method and device

Abstract

The present invention discloses a generalized hybrid visible light modulation method and device. The method comprises: transmitting a generalized ACO‑OFDM signal on part of odd subcarriers and multiplying the signal amplification factor; transmitting DCO on even subcarriers and remaining odd subcarriers. ‑OFDM signal, and multiplied by the signal amplification factor; the generalized ACO‑OFDM signal and DCO‑OFDM signal are respectively subjected to discrete Fourier transform, and the transformed ACO‑OFDM signal is subjected to unipolar processing, and the transformed DCO‑OFDM signal is The OFDM signal is added with a DC bias to obtain the signal frame to be transmitted, and after clipping, digital-to-analog conversion, and filtering, the visible light driving current is controlled to obtain and transmit the visible light communication signal. This method can flexibly allocate system resources, optimize signal amplitude distribution, suppress signal truncation noise, improve communication performance under dimming constraints, balance spectral efficiency and optical power efficiency, and improve overall system performance.

Description

technical field [0001] The invention relates to the technical field of digital signal transmission, in particular to a generalized mixed visible light modulation method and device. Background technique [0002] VLC (Visible Light Communication, Visible Light Communication) is a technical means to realize wireless communication on the basis of LED lighting, which uses a light source to send out high-frequency signals that cannot be detected by the naked eye to transmit information. With its wide spectrum, green energy saving, deep coverage, and the characteristics of organic combination with lighting, it has a good development prospect. [0003] Compared with traditional modulation schemes, such as OOK (On-Off Keying, binary on-off keying) modulation and PPM (Pulse Position Modulation, pulse position modulation) modulation, OFDM (Orthogonal Frequency Division Multiplex, orthogonal frequency division multiplexing) modulation It has the advantages of high spectral efficiency, ...

AI Technical Summary

Problems solved by technology

Among them, DCO-OFDM modulation makes its time-domain signal non-negative by adding DC offset, which is inefficient in terms of optical power; ACO-OFDM modulation only transmits data symbols on odd subcarriers, which is inefficient in terms of bandwidth. High; ADO-OFDM modulates positive polarity ACO-OFDM signals on odd subcarriers, and modulates DCO-OFDM signals on even subcarriers, its bandwidth efficiency is better than ACO-OFDM, and its optical power efficiency is better than DCO-OFDM, but due to ACO -OFDM and DCO-OFDM time-domain signals are both positive numbers, which can easily cause the signal amplitude to be too large and enter the nonlinear region of the system, resulting in truncation and deteriorating system performance

In addition, the number of subcarriers occupied by the above three modulation methods is fixed and cannot be changed according to system requirements.

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