Digital implementation of direction-of-arrival estimation techniques for smart antenna systems

Abstract

Adaptive antenna arrays use multiple antenna elements to form directional patterns in order to improve the performance of wireless communication systems. The antenna arrays also have the ability to detect the direction of incoming signals. These two capabilities allow a smart antenna system to adaptively beamform to more efficiently communicate between nodes. The direction-of-arrival estimation is a crucial component of the smart antenna system that uses open-loop adaptive approach. Historically this estimation has been accomplished using a personal computer. Implementing the estimation in the digital domain has the potential to provide a low cost and light weight solution due to recent advances in digital integrated circuit fabrication processes. Furthermore, digital circuitry allows for more sophisticated estimation algorithms to be implemented using the computational power of modern digital devices. This thesis presents the design and prototyping of direction-of-arrival (DOA) estimation for a smart antenna system implemented on a reconfigurable digital hardware fabric. Two DOA estimation algorithms are implemented and the performance tradeoffs between a custom hardware approach and a microprocessor-based system are compared. The algorithms were implemented for a 5.8 GHz, 8-element circular antenna array and their functionality was verified using a testbed platform. The implementation and analysis presented in this work will aid system designers to understand the tradeoffs between implementing algorithms in custom hardware versus an embedded system and when a hybrid approach is more advantageous.