Indoor positioning method based on optimal channel state information subcarrier

With the development of Wi-Fi technology, the IEEE 802.11n series communication protocol and the subsequent wireless LAN protocols use multiple-input multiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) and other technologies. Channel characteristics between Wi-Fi transceivers can be estimated at the physical layer and stored in the form of channel state information (CSI). However, the propagation of CSI is still affected by indoor multiple paths, and we cannot obtain signals in some corner areas. Therefore, CSI needs a good calibration method to improve the accuracy of the position estimation system. This paper presents an optimal subcarrier screening algorithm. Then the indoor ranging model is fitted based on the CSI subcarrier selected by the algorithm. This paper also provides experimental comparisons of our proposed data generation method with existing indoor ranging methods. Experimental results show that the proposed data generation approach achieves significant ranging accuracy improvement over using the effective CSI ranging method, while it incurs much less computational complexity. Meanwhile, the algorithm improves the influence of multiple paths in a complex indoor environment on location, and the method can obtain more accurate location results.