A Ranging Solution with Multi-channel Splicing in the Single Frequency Band

The channel state information (CSI) extracted from WiFi signals can be used for accurate ranging, which is widely used in indoor localization. The ranging accuracy of the CSI is mainly affected by both the hardware imperfection and the channel bandwidth limitation. The hardware imperfection can lead to signal distortion, while the channel bandwidth limitation can lead to low time resolution. In this paper, we aim to implement a ranging solution with multi-channel splicing in the continuous bandwidth. Concretely, we first investigate the errors that contaminate CSI and mathematically build the round-time trip (RTT) ranging model to eliminate the errors. Then, we propose an OFDM signal splicing principle to achieve bandwidth expansion and use the MUSIC algorithm to estimate the time of flight (ToF). To validate the proposed method, we finally prototype the ranging system using the software defined radio (SDR) platform. The extensive experimental results show that the ranging accuracy is significantly improved provided that we expand the bandwidth with the proposed method.