Theses and Dissertations at Montana State University (MSU)
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Item Reflector modification of the Yagi antenna(Montana State University - Bozeman, College of Engineering, 1954) Smith, Thomas D.Item Reflector spacings of helical beam antennas(Montana State University - Bozeman, College of Engineering, 1954) Marriage, Donald O.Item Huygen's principle applied to the cylindrical antenna boundary value problem(Montana State University - Bozeman, College of Engineering, 1969) Nyhus, Orville KennethItem Design and evaluation of test bed software for a smart antenna system supporting wireless communication in rural area(Montana State University - Bozeman, College of Engineering, 2008) Panique, Michael David; Chairperson, Graduate Committee: Richard Wolff; Yikun Huang (co-chair)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.Item High resolution direction of arrival estimation analysis and implementation in a smart antenna system(Montana State University - Bozeman, College of Engineering, 2010) Khallaayoun, Ahmed; Chairperson, Graduate Committee: Richard WolffThe goal of this research is to equip the smart antenna system designed by the telecommunication group at the department of Electrical and Computer Engineering at Montana State University with high resolution direction of arrival estimation (DOA) capabilities; the DOA block should provide accurate estimates of emitters' DOAs while being computationally efficient. Intensive study on DOA estimation algorithms was carried out to pinpoint the most suitable algorithm for the application of interest, and the spectral methods were chosen for this study. The outcome of the study consisted of generating a novel algorithm, spatial selective MUSIC, which is comparable in accuracy to other high resolution algorithms but does not require the intensive computational burden that is typical of high resolution spectral methods. Spatial selective MUSIC is compared in terms of bias, resolution, robustness and computational efficiency against the most widely used DOA estimation algorithms, namely, Bartlett, Capon, MUSIC, and beamspace MUSIC. The design, troubleshooting, and implementation of the hardware needed to implement the DOA estimation in a real case scenario was achieved. Two design phases were necessary to implement the center piece of the hardware needed to achieve DOA estimation. The 5.8 GHz 8 channel receiver board along with a casing that egg crates the RF channels for channel-to-channel isolation was designed and built. A National Instrument data acquisition card was used to simultaneously sample all the 8 channels at 2.5 MSPS, the data was processed using the PC interface built in LabView. Phase calibration that accounts for the overall system magnitude and phase differences along with a novel calibration method to mitigate the effects of magnitude and phase variations along with mutual coupling was produced during this research and was imperative to achieving high resolution DOA estimation in the lab. The DOA estimation capabilities of the built system was tested within the overall smart antenna system and showed promising results. The overall performance enhancement that the DOA estimation block can provide cannot however be fully realized until the beamforming block is revised to provide accurate and deep null placing along with a narrower beam width. This cannot be achieved with the current system due to limitations in the number of the array elements used and the granularity in the phase shifters and attenuators used in the analog beamformer.Item Digital implementation of direction-of-arrival estimation techniques for smart antenna systems(Montana State University - Bozeman, College of Engineering, 2010) Abusultan, Monther Younis; Chairperson, Graduate Committee: Brock LaMeresAdaptive 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.Item Sequential beamspace smart antenna system(Montana State University - Bozeman, College of Engineering, 2011) Tidd, William Graves; Chairperson, Graduate Committee: Richard WolffThis thesis proposes a design of a novel and innovative sequential beamspace (SBS) smart antenna system. The system is capable of accurate direction of arrival (DOA) estimation in beamspace and efficient beamforming. Moreover, the robust functionality of such a system includes high resolution radio frequency (RF) emitter DOA estimation and beamforming in a noisy environment in the presence of strong interference. Simulations for DOA estimation using beamspace MUSIC and beamspace Capon methods are presented in conjunction with Capon beamforming. These methods are compared and contrasted with proven element space DOA estimation techniques to demonstrate the validity and advantages of pursuing a SBS smart antenna for real-world applications. The beamspace DOA estimation accuracy, resolution, beamforming pattern, and output signal quality have been thoroughly studied and quantified. The algorithms have been tailored to utilize an 8 element uniform circular array (UCA) and an 8 channel analog beamformer (BF) operating at 5.8 GHz to gather lab-based experimental results. The simulations and experimental results show that the proposed system can achieve good performance once it is properly synchronized using a time delay correction filter. In addition, a significant decrease in hardware is realized when operating in beamspace versus element space.