Direct path detection using multipath interference cancelation for communication-based positioning system
1 Bell Centre for Information Engineering, Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario, N6A 5B9, Canada
2 Broadcasting & Telecommunications Convergence Research Laboratory, Electronics and Telecommunications Research Institute, Daejeon, Republic of Korea
EURASIP Journal on Advances in Signal Processing 2012, 2012:188 doi:10.1186/1687-6180-2012-188Published: 30 August 2012
Recent development in wireless communication-based positioning technology brings significant challenge of detecting the weak signal component arriving from the direct propagation path for time-of-arrival (TOA)-based approach. Due to the common obstruction of the direct propagation path in dense multipath environments, identification of the weak direct path in these environments can be very difficult via the classical correlation-based estimator in the presence of interference from significant later arriving multipath components. A new direct path detection scheme using the multipath interference cancelation is presented in this article. For data communication purpose, an iterative estimator with improved accuracy for joint channel and data estimation is first developed; based on which, the interference of multipath components are reconstructed and subtracted from the original received signal. With the aid of the detected data, an enhanced preamble is formulated. The accuracy of direct path detection is substantially improved by using the correlation between the multipath interference-suppressed signal and the enhanced preamble. Semi-analytical expression of the performance of the iterative estimator is derived. The analysis enables the system to determine an automatic stopping criterion to reduce the computational complexity of the iterative process. The performance of the direct path detection is also analyzed in terms of the signal-to-interference-noise ratio (SINR) and compared with that of the conventional approach. Computer simulation results show the superiority of the proposed direct path detection. The accuracy of the positioning system using the proposed method is also evaluated in dense multipath environments.