Optimal direct path detection for positioning with communication signals in indoor environments

Recent development in wireless communication-based positioning systems using time-of-arrival (TOA) methods poses a significant challenge for the estimation of signal propagation time in indoor environments. Due to the possible obstruction of the direct path, the signal component from direct propagation can be very weak and therefore, the performance of TOA estimation will be significantly degraded, especially when the received signal experiences severe multipath propagation effects. An optimal direct path detection algorithm using multipath interference cancellation is proposed in this paper to improve the accuracy of communication-based positioning systems. By maximizing the probability of correct identification between the strong interfering paths and noise-only paths, an optimal threshold is derived for interfering multipath component selection. The interference of multipath components is reconstructed and then subtracted from the received signal to enhance the accuracy of direct path detection. The performance of the proposed algorithm is verified by simulations.