ISBN 978-3-8439-2617-1

978-3-8439-2617-1, Reihe Informationstechnik

Markus Stefer
DoA Estimation With Reduced Hardware Complexity

231 Seiten, Dissertation Universität Bremen (2015), Softcover, A5

Zusammenfassung / Abstract

Direction-of-Arrival (DoA) estimation can look back on a long history starting with the mechanical panning of directional antennas. Improvements were made by utilizing motor-driven rotation of directional antennas before high-resolution DoA estimation methods based on signal processing evolved at the end of the seventies. These expect the antenna signals to be acquired in parallel, and the larger the number of antenna elements the higher the accuracy.

Increasing the number of antennas does not only increase the effort regarding the signal processing, but also regarding the hardware. This is substantiated by the necessity of one complete receiver per antenna that itself consists of different amplifier and mixer stages and the according filters. There fore it is a relevant question whether it is possible to achieve a high-resolution DoA estimation with reduced hardware complexity - and if so, what are the costs in this case. Systems with reduced hardware complexity usually aim at reducing the number of needed receivers significantly.

To be still able to access all the antenna signals, a Single-Pole-Multifold (SPMT) switch is placed between the available receivers and the antenna elements within the array to enable the processing of all antenna signals. Hence, the parallel acquisition of the antenna signals becomes a sequential acquisition. To be able to investigate the systems with reduced hardware complexity more realistically, a model for mobile communication systems known from the literature is presented and modified to fit the model to the task. The modification is necessary regarding the inclusion of the SPMT switch. The presented model is based on the scattering parameter description of the different components in the system. The scattering parameter description is the preferred illustration in radio frequency technology because the transmission properties can be directly read off.

The scattering parameters are of dimension 1 in terms of SI units being another advantage. With the help of these prerequisites, four different systems are described, where patents have been applied for three of these. One of the three uses one receiver without an additional reference antenna. It is suggested to compensate the absence of a reference antenna by using a high-precision reference source for the local oscillator. In this work, the high-precision reference signal is not utilized and the occurring errors are compensated by signal procesing methods with respect to continuous wave source signals. The fourth approach, that cannot be found in the literature, regarding a DoA estimation system with reduced hardware complexity is introduced, explained and derived in the absence of hardware influences.