Estimation of DOA for a smart antenna using a front-end based in FPGA foreseeing a SDR architecture

The Smart Antenna has been proposed as an enabling technology for beam steering in Software Defined Radio (SDR) equipments and can be used to increase the quality in wireless communications link. This paper presents a possible architecture for testing smart antenna algorithms for SDR. The Software Defined Radio Group of University of Brasilia (SDR-UnB) has implemented a small prototype of SDR architecture, which should be able to estimate the Direction of Arrival (DOA) of a signal. The present study deals with the reconfigurability and selectivity of the SDR antennas using a linear uniform array of four antenna elements to estimate the DOA of a signal and the Universal Software Radio Peripheral (USRP) as RF front-end. With the proposal architecture it is possible to evaluate the effects of mutual coupling among the antenna elements caused by the wideband or multiband RF structures used in SDR smart antennas taking into account the co-channel interference. The validation of DOA algorithms can be done in a more realistic way using the prototype.