### Experimental Results
#### 4.2.2 Experimental Results for the Obstacle Detection Component Evaluation
Figure 6: Example of smart backpack for blind persons’ assistance experimental utility: the prototype’s obstacle sensors are able to identify and inform the user that: (**a**) an open glass door is obstructing the path; (**b**) a dispenser is in the path and an open door is found on the user’s right side. Figure 7: Experimental results showing the path taken by four blindfolded users, as they navigated from point A to point B while utilizing the VLC-based smart backpack. The results revealed a notable enhancement in the users’ path and a significant reduction in their travel time: (**a**) With backpack assistance; (**b**) Without any kind of assistance. Discussion and Future Perspectives Regarding the Use of the Visible Light Communications Technology in Visually Impaired Persons' Assistance  
Based on the results of the experimental evaluation, it can be considered that the proposed VLC-based smart backpack concept represents an innovative and versatile solution which has the potential to revolutionize navigation, communication, and safety in both indoor and outdoor environments, helping blind persons to travel in unfamiliar locations. In summary, the proposed VLC-based smart backpack offers several compelling advantages and promising prospects. The VLC technology provides the concept with a versatile data transfer solution which enables seamless data transfer in conjunction with a lighting function, making efficient use of limited power resources. Thus, the use of VLC delivers unlicensed spectrum access and a vast bandwidth of 400 terahertz, providing the support for multiple applications ranging from user localization to location-dependent data distribution. Therefore, different from most of the existing technologies, VLC is very suitable for location-oriented data distribution, providing the user with more relevant information. Accordingly, each luminaire is able to provide the user with accurate and specific information, where the information is correlated with its location, enabling an improved context-aware assistance and navigation. One of the main advantages of VLC use in blind persons' assistance comes from the relatively _simple integration within the preexisting lighting infrastructure_, which offers in turn the support for the development of a ubiquitous assistance solution. In addition, as the proposed solution is developing on a preexisting lighting infrastructure, the implementation cost is partially reduced. The cost-efficiency is also provided by the relatively simple architecture and by its multipurpose functionality. Thus, the cost of the solution becomes controllable, and it could be estimated that the cost of a luminaire upgrade is below 100 euros, a cost that could go even lower if mass production is adopted. Furthermore, the low energy consumption associated with LED use, VLC and light dimming functions further improves the cost-efficiency. For comparison, the operation of a RF-based solution requires continuous energy consumption. On the other hand, in VLC, the data transmission function requires no additional energy consumption as the light used for lighting purposes is also used as a carrier for the data. As lighting systems is present in all public places, from airports to schools and public institutions, the development of such a solution can provide blind persons with access and personalized support in these areas, improving their independence. From the VLC usage point of view, the experimental results have confirmed a very low BER (i.e., ranging within \(10^{-7}\)-\(10^{-6}\)), a wide area coverage, and, very importantly, the compatibility with mobility and light dimming. From this point of view, it is important to emphasize that although there are numerous works that address VLC light dimming capabilities [41; 42; 43; 44], there are only a few that provide experimental demonstrations of such concepts [44].