多光谱可见光通信信道串扰分析  

Analysis of channel crosstalk in muliti-spectrum visible light communication system

作　　者：崔璐[1] 唐义[1] 朱庆炜 骆加彬 胡珊珊[1] 

机构地区：[1]北京理工大学光电学院,光电成像技术与系统教育部重点实验室,北京100081

出　　处：《物理学报》2016年第9期112-119,共8页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2013CB329202);国家自然科学基金项目(批准号:61571067)资助的课题~~

摘　　要：在可见光通信领域,通过波分复用技术可以增加信道个数,从而提高系统通信容量.然而发光二极管(LED)的辐射光谱具有一定线宽,当信道个数增加,信道间隔将变小,尽管有滤光片的通道选择,但LED的辐射光谱会出现重叠从而产生信道串扰.本文基于LED光谱重叠现象分析了多光谱波分复用可见光通信系统的信道串扰问题.首先结合LED的物理机制和实际LED的光谱形状对其光谱进行建模;然后根据光谱重叠现象和可见光通信信道推导出信道串扰公式;最后利用不同中心波长的LED在两通道可见光通信系统中验证了信道串扰公式的正确性.仿真和实验结果表明,当两信道的信道间隔大于28 nm时,两信道之间的信道串扰不超过-13.6 d B.对多光谱波分复用可见光通信系统的信道串扰分析对未来可见光通信增加信道数量有一定指导作用.In visible light communication,the wavelength division mutiplexing（WDM） technology can improve system data rate by increasing the number of channels.However,because the emission spectrum of the light emitting diode（LED） has a certain width,a phenomenon of spectral overlapping will occur when the number of channels increases and channelspacing decreases,which results in channel crosstalk although optical filters are adopted.The channel crosstalk will restrict the capacity of WDM-VLC（visible light communication） system,which has great research significance.In this paper,the channel crosstalk based on LED spectra overapping is disscussed.The LED emission spectrum is modeled by combining the physical mechanism of LED emission with real shape of LED spectrum.According to the literature,the LED shape can be fitted greatly by Gauss function,and the full-width at half-maximum ？E is in a range from about 4.3k_BT_j to 6.8k_BT_j when the peak wavelengths of In Ga N and Al In Ga N LEDs are both less than 560 nm,？E values range from 2.1k_BT_j to 3.3k_BT_j when the peak wavelength of In Al Ga P LED is larger than 560 nm.In order to reduce the overall system complexity we use the following values：when the peak wavelength is less than 560 nm,？E=5.5k_BT_j ;when the peak wavelength is larger than 560 nm,？E=3.0k_BT_j .Then,according to the overlapping spectra and VLC channel with considering optical filter transmittance and detector spectral response,the channel crosstalk formula is derived.Some quantities are given before simulation such as the semi-angle at half illuminance of an LED is 60？;all LEDs are so closely arranged together to mix light in free space that spacing between LEDs can be ignored with respect to the propagating distance;the strongest signal situation is considered.The simulation result shows that although at the same channel spacing,different channels have different crosstalks because spectra are different.And the crosstalk from one adjacent channel will not exceed-13.6 d B when channel-

关 键 词：可见光通信 波分复用 光谱重叠 信道串扰 

分 类 号：TN929.1[电子电信—通信与信息系统]