## 1 Introduction
), the default of the Bluetooth function on mobile devices is on, which also makes it possible to obtain location through Bluetooth. To collect the mobile device's location through Bluetooth it is necessary to deploy the Bluetooth signal to the field where the location will be detected (generally it can be achieved through Beacon) and determine the user's location based on the collected signals. When more accurate or diversified location references are needed, the advertising system needs to deploy more Beacon reference points. Although the cost is still within an acceptable range, subsequent updates and maintenance are also complicate things (such as battery replacement). Even after completing the deployment, other companies can be directly used since all devices can read the Beacon signal. How to collect and analyze the Beacon signal through the mobile device is also a professional problem. These dilemmas finally make the general advertisement delivery system dare to not easily try location collection solutions, which has caused a gap in demand. In some recent researches, there are also some research studies related to indoor positioning that are often mentioned. Through some improvements to signal algorithm processing and the use of IoT-specific communication protocols, indoor positioning accuracy has dramatically surpassed outdoor positioning accuracy. For example, we can use the RSSI signal strength of BLE to improve the accuracy of indoor footprint tracking [1] or, as mentioned here [2], we can use a specific grouping method to improve the accuracy of WiFi for footprint tracking in multi-floor buildings. In addition, this article [3] also mentions that you could use Rola or other IoT-related signal collection for indoor positioning and completely abandon GPS. Even this research [4] also mentioned how to enhance indoor transmission's safety and speed when using 5G wireless technology. However, due to the limitations of some practical problems, such indoor positioning technology still cannot directly replace outdoor positioning technology. This type of indoor communication protocol usually has similar problems, including limited transmission distance or transmission times to save power, the inability to deploy extensively on a large scale, and the lack of extensive support by standard mobile devices. Therefore, even if accuracy has its advantages, it still cannot replace the current mainstream outdoor positioning technology. After 5G appeared, there was a glimmer of hope for the positioning problem. Numerous applications have emerged with 5G, such as the Internet of Vehicles (VANET) and Wireless Metropolitan Area Network (WMAN) [5; 6]. Due to the maturity of various software-defined networks (SDNs) [7], device-to-device (D2D) direct communication [8], and dynamic allocation of connection resources [9], the transmission speed and volume of the 5G environment have been significantly improved compared to the past. Even in some places where it is not easy to build a base station, there are studies to provide UAV-assisted technology as a wireless transmission solution [10]. Since the high-speed wireless transmission has covered the entire city, outdoor positioning in the 5G era is no longer a problem. In fact, telecom operators have had better ways to do this in the past than the advertising system companies that use GPS, WiFi, and Bluetooth for positioning. Through the base station signal and the three-point positioning algorithm, telecom operators can locate the mobile device's location. However, its accuracy is still limited. Besides, being limited by storage space, it is impossible to store all the data all the time. Most importantly, since the information can only be obtained by telecom operators, such a geographic positioning solution does not actually appear in the general advertising system. Now thanks to the advent of the 5G era, various nearby mobile devices can be quickly connected to each other.