| Popis: |
This thesis proposes a design for a cognitive array system for next generation wireless communication systems, combining the techniques of cognitive radios and adaptive array systems. This novel array system allows for the possibility of greater spectral usage and reuse, and improved communication ranges. In this thesis, numerous algorithms were studied to map an RF environment in both spatial and spectral domains that would be useful in this system. Towards this goal, direction of arrival estimation, frequency sensing and spectral hole finding algorithms were studied, in addition to a joint frequency and direction of arrival estimation algorithm. Beamforming was also studied as a means of improving signal quality and increasing range. Once the direction to a target was found, localization and tracking were studied to further refine the target's position and change in position over time. After the algorithms were studied in simulation to determine their properties, hardware calibration was performed followed by laboratory tests of the methods with a uniform circular array testbed at Montana State University to verify the expected performances. |
