DOA estimation methods with unknown number of sources

• Main Author: Wang, Zhizheng
• Other Authors: Ng Boon Poh
• Format: Thesis-Master by Research
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Electrical and electronic engineering::Antennas, wave guides, microwaves, radar, radio; Engineering::Electrical and electronic engineering::Wireless communication systems
• Online Access: https://hdl.handle.net/10356/140553
• Institution: Nanyang Technological University

Direction of arrival (DoA) estimation is a major topic investigated in smart antenna and array signal processing area of wireless communication. It is closely linked to source localization which provides the spatial information of the signal sources. In this thesis, the conventional MUSIC algorithm is studied and interpreted as a MVDR estimator with infinite input signal power. An alternative high-resolution DoA estimation method is introduced based on this interpretation. Instead of signal power, the noise power is now set to be negative infinite in dB. Subsequently, the scanning method in the conventional MUSIC algorithm is re-designed in order to reduce the computational load. The new scanning method takes advantage of the relationship between spectrum parameters and the number of array elements to minimize the number of direction scans while remain the quality of resolution. A new Unity-Response-Like (UR-Like) high-resolution estimation method without number of sources is proposed and examined with numerical simulations. The idea behind the UR-Like algorithm is to maintain the difference between array response and unity over the field of view while minimizing the mean output power. The UR-Like algorithm is also compared with a competitive algorithm, the MUSIC-Like algorithm. With the same design requirement of high-resolution DoA estimation method without number of sources, the UR-Like has the advantage of less computational load against the MUSIC-Like algorithm. Last but not least, the UR-Like algorithm is extended to wideband scenarios with the help of the frequency scanning and the Taylor series methods. The Taylor series method is later applied to the MUSIC-Like and the MVDR algorithms for wideband extension as well.