In-Band Full Duplex Analog Control and Analysis

187695-Thumbnail Image.png
Description
In-Band Full-Duplex (IBFD) can maximize the spectral resources and enable new types of technology, but generates self-interference (SI) that must be mitigated to enable practical applications. Analog domain SI cancellation (SIC), usually implemented as a digitally controlled adaptive filter, is

In-Band Full-Duplex (IBFD) can maximize the spectral resources and enable new types of technology, but generates self-interference (SI) that must be mitigated to enable practical applications. Analog domain SI cancellation (SIC), usually implemented as a digitally controlled adaptive filter, is one technique that is necessary to mitigate the interference below the noise floor. To maximize the efficiency and performance of the adaptive filter this thesis studies how key design choices impact the performance so that device designers can make better tradeoff decisions. Additionally, algorithms are introduced to maximize the SIC that incorporate the hardware constraints. The provided simulations show up to 45dB SIC with 7 bits of precision at 100MHz bandwidth.
Date Created
2023
Agent

Distributed Coherent Mesh Beamforming: Algorithms and Implementation

187540-Thumbnail Image.png
Description
In this dissertation, I implement and demonstrate a distributed coherent mesh beamforming system, for wireless communications, that provides increased range, data rate, and robustness to interference. By using one or multiple distributed, locally-coherent meshes as antenna arrays, I develop an

In this dissertation, I implement and demonstrate a distributed coherent mesh beamforming system, for wireless communications, that provides increased range, data rate, and robustness to interference. By using one or multiple distributed, locally-coherent meshes as antenna arrays, I develop an approach that realizes a performance improvement, related to the number of mesh elements, in signal-to-noise ratio over a traditional single-antenna to single-antenna link without interference. I further demonstrate that in the presence of interference, the signal-to-interference-plus-noise ratio improvement is significantly greater for a wide range of environments. I also discuss key performance bounds that drive system design decisions as well as techniques for robust distributed adaptive beamformer construction. I develop and implement an over-the-air distributed time and frequency synchronization algorithm to enable distributed coherence on software-defined radios. Finally, I implement the distributed coherent mesh beamforming system over-the-air on a network of software-defined radios and demonstrate both simulated and experimental results both with and without interference that achieve performance approaching the theoretical bounds.
Date Created
2023
Agent

Precision Navigation using Two-Way Ranging: Bounds and Performance

168693-Thumbnail Image.png
Description
Localization tasks using two-way ranging (TWR) are making headway in modern daynavigation applications as an alternative to legacy global navigation satellite systems (GNSS) such as GPS. There is not currently literature that provides a closed-form expression for estimation performance bounds on position

Localization tasks using two-way ranging (TWR) are making headway in modern daynavigation applications as an alternative to legacy global navigation satellite systems (GNSS) such as GPS. There is not currently literature that provides a closed-form expression for estimation performance bounds on position and attitude when a TWR system is employed. A Cramer-Rao Lower Bounds (CRLB) is derived for position and orientation estimation using both 2-D and 3-D geometries. A literature review is performed to give background and detail on the tools needed for a thorough analysis of this problem. Popular Least Squares techniques and solutions to Wahba’s problem are compared to the derived bounds as proof of correctness using Monte Carlo simulations. A brief exploration on estimation performance using an Extended Kalman Filter for non-stationary users is also looked at as an introduction to future extensions to this work. The literature Applications like the CHP2 system are discussed as well to show how secure, inexpensive and robust implementation of TWR is highly feasible. i
Date Created
2022
Agent

Simultaneous Positioning and Communications: Hybrid Radio Architecture, Estimation Techniques, and Experimental Validation

157986-Thumbnail Image.png
Description
Limited spectral access motivates technologies that adapt to diminishing resources and increasingly cluttered environments. A joint positioning-communications system is designed and implemented on \acf{COTS} hardware. This system enables simultaneous positioning of, and communications between, nodes in a distributed network

Limited spectral access motivates technologies that adapt to diminishing resources and increasingly cluttered environments. A joint positioning-communications system is designed and implemented on \acf{COTS} hardware. This system enables simultaneous positioning of, and communications between, nodes in a distributed network of base-stations and unmanned aerial systems (UASs). This technology offers extreme ranging precision ($<$ 5 cm) with minimal bandwidth (10 MHz), a secure communications link to protect against cyberattacks, a small form factor that enables integration into numerous platforms, and minimal resource consumption which supports high-density networks. The positioning and communications tasks are performed simultaneously with a single, co-use waveform, which efficiently utilizes limited resources and supports higher user densities. The positioning task uses a cooperative, point-to-point synchronization protocol to estimate the relative position and orientation of all users within the network. The communications task distributes positioning information between users and secures the positioning task against cyberattacks. This high-performance system is enabled by advanced time-of-arrival estimation techniques and a modern phase-accurate distributed coherence synchronization algorithm. This technology may be installed in ground-stations, ground vehicles, unmanned aerial systems, and airborne vehicles, enabling a highly-mobile, re-configurable network with numerous applications.
Date Created
2019
Agent