Super receivers for visible light communications

用于可见光通信的超级接收器

• 批准号: 2743395
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2743395
• 关键词: Super; receivers; visible; light; communications

I. IntroductionConsidering the limited radio spectrum, visible light communication (VLC) using an unlicensed light spectrum nowadays offers an opportunity to create a new wireless infrastructure for data transmission and daily indoor illumination, playing a vital role in the coming Internet of Things (IoT). Compared with conventional radio frequency (RF), VLC based on LEDs has better confidentiality and low-power consumption. It is always immune to electromagnetic interference, especially in places full of electronic equipment. Researching this field will soon contribute to compatible standardization of lighting and telecom infrastructures, and establish an open architecture guide for the upcoming IoT.II. Research QuestionsOnce the new wireless network is constructed directly from existing prototypes, the sensitivity and bandwidth limitations of the optical receivers on terminals is the key bottleneck. Considering the eye safety and standards for interior illumination, the amount of received light is limited. Therefore, the maximum data rate of a VLC system is ultimately determined by the sensitivity of receivers. For receivers, one of the important constraints is the etendue conservation. Increasing the active area of the photodetector can enhance the received optical power but lead to lower bandwidth due to larger capacitance. Once typical concentrators are included for a receiver, there is always a trade-off between optical gain and field-of-view (FoV) because of the etendue conservation. Accordingly, fluorescent concentrators, which first absorb then re-emit as a medium, are proposed to simultaneously provide a high optical gain and a wide FoV for receivers. Nevertheless, most of the current works have limited data rates of 10-40 Mbps due to low SNR and bandwidth. They can hardly work in a complex environment such as underwater conditions or mobile communication. Therefore, it is necessary to design a super receiver solution to access a large number of terminals in the IoT, which ensures the stability and efficiency of optical wireless communications.III. Research MethodologyGiven my past research and knowledge, I will consider optoelectronic devices designs and algorithm optimization to meet the above challenges. a) Fluorescent Concentrators and Silicon PhotomultiplierSince the large lifetime is the main factor limiting the modulation bandwidth of receivers, it is necessary to find a short-lifetime fluorescent material with high quantum efficiency. Meanwhile, extending the active region of PD by films or plastic optical fibers, the light from different directions could be received simultaneously with mitigated alignment criteria. Moreover, a light detector capable of detecting individual photons can be introduced in the receiver to improve the sensitivity. In this way, realizing a large-scale and efficient detector array will be possible, where spatial diversity can greatly enhance the data rate. b) Algorithm Optimization and ExtensionBenefiting from the color converter's concentration performance, we can support multiple users simultaneously without complex lenses and provide a single user with moderate mobility. With the multiple access and MIMO methods, the system could be extended by times, requiring no extra separation by wavelength and polarization states. To obtain better performance, equalization algorithms including pre-leveling, clipping, and complex post-equalization are inevitably utilized to improve the data rate.IV. Alignment to EPSRC's strategies and research areasThis project falls within the EPSRC Optical communications research area.

由于无线电频谱有限，当今使用非许可频谱的可见光通信(VLC)为数据传输和日常室内照明提供了一个新的无线基础设施，在即将到来的物联网(IoT)中发挥着至关重要的作用。与传统的射频相比，基于LED的VLC具有更好的保密性和低功耗。它始终不受电磁干扰，特别是在电子设备林立的地方。研究这一领域将有助于照明和电信基础设施的兼容标准化，并为即将到来的物联网建立一个开放的体系结构指南。II.研究问题一旦新的无线网络直接由现有的原型构建，终端上光接收器的灵敏度和带宽限制是关键的瓶颈。考虑到眼睛的安全和室内照明的标准，接收的光量是有限的。因此，VLC系统的最大数据速率最终由接收机的灵敏度决定。对于接收者来说，其中一个重要的制约因素就是张量守恒。增加光电探测器的有源面积可以提高接收光功率，但由于电容较大，导致带宽较低。一旦将典型的聚光器包括在接收器中，由于张量守恒，总是在光学增益和视场(FOV)之间进行权衡。因此，作为一种介质，首先吸收然后再发射的荧光集中器被提出，以同时为接收器提供高的光增益和宽的视场。然而，由于低信噪比和低带宽，目前大多数工作的数据速率都限制在10-40 Mbps。它们很难在复杂的环境中工作，如水下条件或移动通信。因此，有必要设计一种超级接收器解决方案来接入物联网中的大量终端，以确保光无线通信的稳定性和效率。三、研究方法根据我过去的研究和知识，我会考虑光电子器件设计和算法优化来应对上述挑战。A)荧光集中器和硅光电倍增管由于长寿命是限制接收器调制带宽的主要因素，因此有必要寻找一种具有高量子效率的短寿命荧光材料。同时，通过薄膜或塑料光纤扩展PD的有源区，可以同时接收来自不同方向的光，并且减轻了对准准则。此外，还可以在接收器中引入能够检测单个光子的光探测器，以提高灵敏度。这样，就有可能实现大规模、高效的探测器阵列，其中空间分集可以大大提高数据速率。B)算法优化和扩展得益于色彩转换器的集中性能，我们可以同时支持多个用户，而无需复杂的镜头，并为单个用户提供适度的移动性。利用多址接入和MIMO方法，系统可以成倍地扩展，不需要额外的波长和偏振态分离。为了获得更好的性能，不可避免地会使用包括预平平、限幅和复数后均衡在内的均衡算法来提高数据速率。IV.与EPSRC的策略和研究领域保持一致本项目属于EPSRC光通信研究领域。