Design and evaluation of test bed software for a smart antenna system supporting wireless communication in rural area

Abstract

This paper explores the design and development of a test bed to analyze feasibility of utilizing adaptive smart antennas in conjunction with high bandwidth WiMAX radio systems to achieve improved performance for mobile nodes and to suppress potential interference from unwanted signals. Although the new WiMAX standard offers the potential for using smart, adaptive antennas, this functionality has not been implemented. This design serves as a common platform for testing adaptive array algorithms including direction of arrival (DOA) estimation, beamforming, and adaptive tracking, as well as complete wireless communication with a WiMAX radio. Heavy emphasis will be placed on ease of implementation in a multi-channel / multi-user environment. Detailed here, is the design and development of an 8-channel adaptive smart antenna test bed for WiMAX radio systems. The test bed consists of an 8-element circular antenna array, a PC running a software interface, and RF receiver and transmission boards which enable DOA estimation and beamforming to take place. We have developed a LabVIEW interface for a PC controlled smart antenna test bed supporting two mobile targets. The main system has three components, DOA estimation and signal validation, beamforming (null steering or multi-beam), and target tracking. The interface is implemented in a modular fashion so that a maximum amount of flexibility is available to test bed users. The test bed was used in conjunction with MATLAB simulations to analyze DOA estimation, beamforming, and nullsteering algorithms necessary to realize a smart antenna system capable of handling multiple users and suppressing nearby strong interference. The results of tests run using the test bed showed that communication delay and hardware limitations on the RF transmission board were a limiting factor in the performance of the smart antenna system.