# Advanced Progress of Optical Wireless Technologies for Power Industry: An Overview
## 4 Challenges and Potential of Power Industry Optical Wireless Communications  
At present, optical wireless technology for smart power is still in the broadcast technology paradigm. In this case, the power line transmits data from the data source to the data driving module, and the data driving module loads the same data stream on all light sources, and broadcasts the signal to the area covered by the light signal through the light source. This means that even if there are multiple distributed light sources, the data transmission potential of each light source cannot be fully released. In view of these problems, it is feasible to introduce MIMO technology into optical wireless technology. The basic idea is to realize multiple data streams separately to multiple distributed sources through the indoor power line network. The light source completes the loading of each data stream through its own efforts and transfers the optical signal from different data information. At the receiving end, the optical signals from different light sources are converted into electrical signals by multiple detectors, and then the original multiple streams are restored through various demultiplexing techniques. Theoretically, MIMO technology paradigm can double the transmission capacity of the system. It must be pointed out that, unlike the radio frequency MIMO technology in the current commercial cellular network, the wireless optical MIMO technology based on the indoor distribution network must comprehensively consider the MIMO characteristics of the distribution network itself [126; 127; 128; 129]. Generally speaking, mainstream alternating current power supply networks use a three-phase power supply. How to eliminate the transmission interference between the neutral line, the live line, and the ground line may become the key to the practical application of high-power optical wireless technology in MIMO technology. In addition, since OMA only allocates a single wireless resource to one user, such as by frequency or time, NOMA scheme allows multiple users to use the same resource. In some of the scenes, such as the near-far effect scenario and the scenario of multi-node access with wide coverage, NOMA approach using power multiplexing has obvious performance advantages over traditional OMA and is more suitable for future system deployment. In the field of power industry optical wireless channel modeling and characterization, the existing research works cannot fully cover the diverse power grid configurations at home and abroad, nor can it be applied to the extensive non-Lambert wireless optical link configurations. Existing PLC studies show that due to the different standards of power industry, the transmission characteristics of smart grid in different countries and regions are obviously different, and it is difficult to use a single model to represent [128; 129; 130]. At the same time, as the original function of the electric power network is not used for data transmission, power grid load and electricity demand in the different periods have an obvious dynamic difference; these factors make the electric model to be further points area, the scene, the difference of the period of time to discuss, and integrate wireless optical link corresponding channel measurement and statistical analysis. Meanwhile, to meet the diverse lighting needs of roads, assembly halls and exhibition halls, the actual commercial LED light sources usually need to use the encapsulation lens technology to distribute the light beam, improve the light efficiency and improve the lighting uniformity [131; 132; 133]. This kind of technology processing results in the beam of LED light that no longer match the Lambert model in the existing theoretical analysis, and ultimately leads to the reduction of the accuracy of the power wireless optical modeling analysis results, and even the analysis of the practical significance of modeling representation.