A multiple antenna wireless testbed for the validation of DoA estimation algorithms

Abstract

In this paper, a wireless testbed with a multiple antenna receiver is described. It comprises a rotating four-element antenna array connected to a quad radio frequency (RF) front-end, and a channel acquisition board equipped with a field programmable gate array (FPGA). The algorithms can be implemented directly on the FPGA, but they can also be tested via simulation, e.g., with Matlab, since the acquired data can be transferred from the board memory to a personal computer (PC). Moreover, the algorithm implementation on the FPGA can be done by exploiting the System Generator for DSP Xilinx tool that allows the algorithm synthesis from a Simulink block diagram. These features make the testbed useful for rapid prototyping. In particular, the presence of the rotating antenna array enables the analysis of direction of arrival (DoA) estimation techniques. We report the main results from the experimental measures conducted to characterize the hardware non idealities. We then describe a DoA estimation algorithm that has been used to compare real and simulated results. It is shown that the results are in good agreement with the simulations, also when the effect of non isotropic antenna gains and/or phase noise originated from non co-phased RF front-ends becomes considerable.