Wang Ke, Song Tingting, Kandeepan Sithamparanathan, Li Hongtao, Alameh Kamal
Opt Express. 2021 Feb 1;29(3):4582-4595. doi: 10.1364/OE.409395.
The optical wireless communication (OWC) technology has been widely studied to provide high-speed communications in indoor environments. The indoor OWC-based positioning function is also highly demanded and the received signal strength (RSS) method has attracted intensive interests, where multiple transmitters are used and the positioning information is provided by estimating the channel gain from each transmitter with known location. However, this process normally requires dedicated positioning time slots, RF carriers or codewords, which limit the system data rate and throughput. To solve this limitation, in this paper we propose a filter-enhanced indoor OWC positioning scheme, where spatial waveform shaping filters are applied to the transmitters, thus enabling the signals from different transmitters to be separated via matched filters at the receiver side. Hence, this approach allows the RSS information to be obtained from the wireless communication signal directly and the positioning function realized without affecting the wireless communication data rate or throughput. In addition, since positioning is realized using the communication signal, continuous positioning can be achieved for real-time tracking. The proposed filter-enhanced positioning scheme is experimentally demonstrated in a near-infrared indoor OWC system with laser transmitters. Results show that an average positioning accuracy of 5.41 cm and 2.5 Gb/s wireless communication are achieved simultaneously. The proposed filter-enhanced positioning scheme can also be applied in visible light communication (VLC) systems with LED transmitters, and the feasibility is verified via simulations. The proposed filter-enhanced scheme provides a promising positioning method in indoor OWC systems without affecting the wireless data communication.
光学无线通信（OWC）技术已被广泛研究，以在室内环境中提供高速通信。基于室内OWC的定位功能也有很高的需求，接收信号强度（RSS）方法引起了广泛关注，该方法使用多个发射器，并通过估计来自每个已知位置发射器的信道增益来提供定位信息。然而，这个过程通常需要专用的定位时隙、射频载波或码字，这限制了系统的数据速率和吞吐量。为了解决这一限制，在本文中，我们提出了一种滤波器增强的室内OWC定位方案，其中在发射器处应用空间波形整形滤波器，从而使来自不同发射器的信号能够在接收器端通过匹配滤波器分离。因此，这种方法允许直接从无线通信信号中获取RSS信息，并在不影响无线通信数据速率或吞吐量的情况下实现定位功能。此外，由于使用通信信号实现定位，因此可以实现连续定位以进行实时跟踪。所提出的滤波器增强定位方案在具有激光发射器的近红外室内OWC系统中进行了实验验证。结果表明，同时实现了5.41厘米的平均定位精度和2.5 Gb/s的无线通信。所提出的滤波器增强定位方案也可以应用于具有LED发射器的可见光通信（VLC）系统，并通过仿真验证了其可行性。所提出的滤波器增强方案为室内OWC系统提供了一种有前景的定位方法，而不会影响无线数据通信。
