Superresolution TOA Estimation With Computational Load Reduction

Although the superresolution multipath delay profile (MDP) estimation technique enhances the time resolution of a low-resolution MDP by using matrix computations, the computational load for the matrix computations is a problem, because it drastically increases with the length of the MDP. Because positioning systems require the time of arrival (TOA) of the first path only, it is possible to reduce the computational load by applying the matrix computations only to the part of the MDP that is narrowed but still includes the TOA of the first path. This paper proposes a scheme for determining the observation window of MDP from the low-resolution TOA estimates, which are obtained from the MDPs produced by the pseudonoise correlation method. The proposed scheme makes use of the random nature of the low-resolution TOA estimates to further reduce the observation window. The computational efficiency and estimation accuracy of the proposed scheme are examined by channel simulations based on the Saleh-Valenzuela indoor channel model and are also compared with the computational efficiency and estimation accuracy of the conventional superresolution technique without the observation window reduction.