Space-Time Doppler Spread Estimation in Mobile Fading Channels

The Doppler spread, or the mobile speed, reflects how fast in time the fading is experienced by the receiver, and its knowledge is useful for many mobile communication subsystems. In this paper we propose a new speed estimator at the base station, where multiple antennas are available. The estimator is an extension of the single-antenna speed estimation technique proposed in [1]. By taking advantage of the spatial information provided by an antenna array at the base station, the new low-complexity estimator performs very well over a wide range of noise power, nonisotropic scattering, and line-of-sight component, verified by extensive Monte Carlo simulations. The superior performance of the new estimator is further illustrated by comparing with the conventional speed estimation techniques.