False alarm probability-based estimation of multipath channel length

In this letter, a multipath channel length estimation algorithm is proposed. It consists basically of estimating all path delays using a threshold comparison-based criterion. The threshold is obtained by imposing a fixed false alarm probability on the detection of each path delay. Assuming that the shortest delay is normalized to be equal to zero, the largest one is then selected to provide the desired length estimate. The threshold is analytically derived in the letter under the hypothesis that the channel impulse response (channel IR) estimate is corrupted by additive white Gaussian noise. Simulation results for the Universal Mobile Telecommunication System-Time Division Duplex are presented, which show that the proposed algorithm affords a detector performance very close to the case when the channel IR length is a priori known.