Estimation of the Velocity of a Walking Person in Indoor Environments from mmWave Signals

Abstract

The present work is motivated by the growing interest in using millimeter-wave (mmWave) bands in future wireless indoor communications. For a variety of wireless indoor applications, such as remote medical care, healthcare services, and human-machine interaction, it is of crucial importance to estimate the velocity of walking persons in indoor environments with high precision. In this paper, we present a novel procedure for estimating the velocity of a walking person in indoor environments by using mmWave signals. The indoor environment is considered to be equipped with a distributed $2\times 2$ multiple-input multiple-output (MIMO) system operating in the 60 GHz band. The proposed approach requires first to estimate the time-variant Doppler frequencies by fitting the spectrogram of the complex channel gain of a non-stationary indoor channel model to the spectrogram obtained from the received mmWave signals. The velocity of the moving person is then deduced from estimated time-varying Doppler frequencies. Numerical results, comparing the estimated Doppler frequencies and velocity with corresponding exact values, known from generated mmWave signals, are provided to demonstrate the validity of the proposed velocity estimation algorithm.