摘要
Abstract
With the advantages of immunity to electromagnetic interference,abundant spectrum resources,and convenient deployment,visible light communication(VLC)has become a core solution for the implementation of indoor integrated sensing and communication(ISAC).It can simultaneously realize high-speed indoor communication and high-precision position sensing,and is applicable to diverse scenarios such as smart homes,indoor positioning,and intelligent buildings.However,the conventional fast Fourier transform-based orthogonal frequency division multiplexing(FFT-OFDM)waveform presents prominent technical limitations when applied to VLC-ISAC systems,which severely restrict the integrated system performance.The FFT-OFDM waveform suffers from a high peak-to-average power ratio(PAPR).Given the inherent nonlinear transmission characteristics of light-emitting diodes(LEDs),a high PAPR easily induces clipping distortion,resulting in signal distortion and signal-to-noise ratio degradation.This seriously degrades the extraction accuracy of sensing parameters such as indoor distance and position based on received signal strength(RSS).Meanwhile,existing multi-light-source discrimination schemes heavily rely on sinusoidal frequency markers,which occupy additional spectrum resources,increase system spectrum overhead,and reduce communication efficiency as well as the cost-effectiveness of integrated sensing and communication.To address the above issues,this paper proposes a novel VLC-ISAC waveform design scheme based on lifting wavelet transform(LWT).By introducing Haar wavelet and leveraging its excellent time-frequency localization characteristics,the proposed method optimizes waveform features to effectively suppress PAPR and mitigate signal degradation caused by LED nonlinear distortion.Furthermore,the orthogonal characteristics of wavelet bases enable pilot multiplexing,which eliminates the need for additional sinusoidal frequency markers and completely avoids extra spectrum overhead.Simulation results demonstrate that compared with the traditional FFT-OFDM scheme,the proposed method achieves effective PAPR reduction and significant suppression of LED nonlinear clipping distortion.It realizes high-precision separation and extraction of spatial sensing features for multiple light sources with zero additional bandwidth overhead,and substantially improves the integrated sensing and communication performance of VLC systems in nonlinearity-limited environments.This work provides a reliable technical reference for the practical engineering deployment of indoor VLC-ISAC systems.关键词
可见光通信/通感一体化/波形设计/提升小波变换Key words
visible light communication/integrated sensing and communication/waveform design/lifting wavelet transform分类
航空航天
