Wang Ke, Nirmalathas Ampalavanapillai, Lim Christina, Skafidas Efstratios
National ICT Australia – Victoria Research Laboratory (NICTA-VRL), VIC 3010, Australia.
Opt Express. 2012 Apr 9;20(8):8442-56. doi: 10.1364/OE.20.008442.
In this paper we experimentally investigate a gigabit indoor optical wireless communication system with single channel imaging receiver. It is shown that the use of single channel imaging receiver rejects most of the background light. This single channel imaging receiver is composed of an imaging lens and a small photo-sensitive area photodiode attached on a 2-axis actuator. The actuator and photodiode are placed on the focal plane of the lens to search for the focused light spot. The actuator is voice-coil based and it is low cost and commercially available. With this single channel imaging receiver, bit rate as high as 12.5 Gbps has been successfully demonstrated and the maximum error-free (BER<10⁻⁹) beam footprint is even larger than 1 m. Compared with our previous experimental results with a single wide field-of-view non-imaging receiver, an improvement in error-free beam footprint of >20% has been achieved. When this system is integrated with our recently proposed optical wireless based indoor localization system, both high speed wireless communication and mobility can be provided to users over the entire room. Furthermore, theoretical analysis has been carried out and the simulation results agree well with the experiments. In addition, since the rough location information of the user is available in our proposed system, instead of searching for the focused light spot over a large area on the focal plane of the lens, only a small possible area needs to be scanned. By further pre-setting a proper comparison threshold when searching for the focused light spot, the time needed for searching can be further reduced.
在本文中，我们对一种采用单通道成像接收器的千兆位室内光无线通信系统进行了实验研究。结果表明，使用单通道成像接收器可抑制大部分背景光。这种单通道成像接收器由一个成像透镜和一个附着在双轴致动器上的小光敏面积光电二极管组成。致动器和光电二极管放置在透镜的焦平面上，以搜索聚焦光斑。该致动器基于音圈，成本低且可商购。利用这种单通道成像接收器，已成功演示了高达12.5 Gbps的比特率，并且最大无差错（误码率<10⁻⁹）光束覆盖范围甚至大于1米。与我们之前使用单个宽视场非成像接收器的实验结果相比，无差错光束覆盖范围提高了20%以上。当该系统与我们最近提出的基于光无线的室内定位系统集成时，可以为整个房间的用户提供高速无线通信和移动性。此外，还进行了理论分析，模拟结果与实验结果吻合良好。此外，由于在我们提出的系统中用户的大致位置信息是可用的，因此无需在透镜焦平面上的大面积区域搜索聚焦光斑，只需要扫描一个小的可能区域。通过在搜索聚焦光斑时进一步预先设置适当的比较阈值，可以进一步减少搜索所需的时间。
