Time delay and direction of arrival estimation of multiple users in slow fading channels

In this paper, the spatial diversity is used to handle the problem of estimating the multipath propagation parameters of multiple users that interfere both in time and frequency. This issue is investigated in the case of slow fading channels. By assuming that the channel is stationary over a set of time slots, we recover each user channel impulse response by use of pilot symbols. A subspace-based algorithm is then separately applied on each user restored channel to sequentially recover the corresponding paths time delays and directions of arrival. For this, one-dimensional spectra optimizations are used. A kind of paths isolation guarantees the pairing between the estimated delays and angles.