I. Introduction
In recent years, as modernization has accelerated, the number of large public buildings and places has increased rapidly [1], greatly expanding the scope of indoor space. The global spread of the Corona Virus Disease 2019 (COVID-19) has forced people to spend numerous time indoors [2]. On the other hand, with the rapid development of smart phones and Micro Electro-Mechanical System (MEMS) technology, the public demand for mobile information services based on indoor location is increasing gradually [3].