Multiplexing technique for direction of departure and direction of arrival estimation

Abstract

A novel multiplexing technique for angular estimation that avoids the use of switches and multiple RF chains is presented. The principle of operation is as simple as connecting cables of different electrical lengths to the antennas. The advantages are simplicity and fast measurements, which enables the study of time-variant channels. If the duration of the excitation signal is less than a certain limit (which depends on the delays introduced by cables and on the delay spread of the propagation channel), the technique performs a time-domain multiplexing. However, the technique is especially interesting in the case that the excitation signal duration exceeds this limit. In that case, it requires the frequency of the signal to increase or to decrease linearly in time, regardless if the variation is discrete or continuous in time. The post-processing of the receiver output used to separate the signals corresponding to each antenna is detailed in this study. Once separated, the signals can be processed with a high-resolution algorithm to estimate the direction of departure and the direction of arrival. To validate the capability of this method, simulation results and measurements in an anechoic chamber are presented.