基于白光LED照明光源的室内VLC系统

LED照明与可见光通信技术相结合,构建出基于LED可见光无线通信系统。对室内VLC(Visible Light Communication)系统的白光LED光源特性和系统信道模型分析,提出照明光源布局设计与接收光功率分布的关系;对强度调制直接检测方式的室内VLC系统中信噪比和多径效应引起的码间串扰分析,提出采用光分集接收技术克服码间串扰和提高信噪比,并给出光检测器阵列布局的模型。建立VLC系统仿真模型,给出OOK-NRZ (On-Off Keying & Non-Return Zero)和OOK-RZ(On-Off Keying & Return Zero)调制方式的误码率和均方根时延扩展之间的关系曲线。仿真结果表明,接收光功率相同时,均方根时延扩展时间大于1.0 ns时,OOK-RZ特性优于OOK-NRZ。

Indoor Visible-light Communication System Based on White LED

White LEDs have high power output, high efficiency and long lifetime, and are expected to serve as lighting of the next generation. Visible light LEDs are being used for indoor optical wireless communication system as well as the illumination of rooms. The visible light communication (VLC) system based on LEDs can attain high luminosity as a lighting source, and thus high quality transmission for an optical wireless system. In indoor diffuse optical wireless links multi-path dispersion limits the maximum transmission data rates. White LED light source, SNR, system channel model and RMS delay spread have been analyzed for indoor VLC system. The relation between optimal strategies of light source and received optical power was discussed. SNR of indoor VLC system based IM-DD and ISI produced by multi-path impulse response was investigated. The optical diversity reception technology was given to get rid of ISI and increase the SNR. And the model of the optical detectors layout was given. The system simulation model was built, and the relation curves between BER and RMS delay spread of OOK-NRZ modulation and OOK-RZ modulation were given. Based on the experimental results and under the same received optical power and RMS delay spread time of greater than 1.0 ns, OOK-RZ requires a wider band-width than OOK-NRZs, since it shows a better performance than OOK-NRZ.