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Ultra-Wideband On-Site-Coding-Receiver for Digital Beamforming Applications
Alwan, Elias Antoun

2014, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
There is significant interest to integrate a variety of high speed communications using a single multifunctional front-end (transceiver) matched to an ultra-wideband (UWB) aperture. The availability of small UWB conformal apertures can provide a new paradigm in the way we collect and process information. However, utilization of this bandwidth imposes several requirements on the aperture, starting with a wideband feed network and the ability to scan down to low angles over the entire purported bandwidth (at least down to 70 degrees). Concurrently, a scalable and power-efficient digital back-end is needed to realize digital beam-forming for cognitive sensing.

UWB transceivers are essential to realizing cognitive radio (CR) and software defined radio (SDR) systems. A perennial challenge is the tradeoff between size, gain, and bandwidth. That is, the design of low profile, power-efficient, wideband conformal transceivers is desirable for conformal integration on small platforms.

We propose a novel transceiver architecture for cognitive sensing. The architecture supports agile beam forming, jamming mitigation, as well as MIMO communications. An essential aspect of the new architecture is its departure from the traditional digital beamforming approaches. Specifically, a single ADC is assigned to a group of array elements instead of having one ADC per element. To facilitate this approach, code division multiplexing (CDM) is applied to each received antenna signal prior to combining them for digitization using a single ADC. Thus full signal recovery is possible at the digital baseband via decoding. The proposed architecture significantly reduces the number of ADCs and I/O channels and hence drastically improves size, weight, area, power and cost of the system with minimal impact on the receiver's signal-to-noise ratios (SNR) and phase.

We also present a two-channel hardware realization of the proposed receiver using a BPSK modulated input signal. The objective is to demonstrate on-site coding by simulating the system using purely discrete components. Measurements showed that the signals can be faithfully recovered with minimum errors.
John L. Volakis (Advisor)
Waleed Khalil (Committee Member)
Kubilay Sertel (Committee Member)
221 p.

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Alwan, E. (2014). Ultra-Wideband On-Site-Coding-Receiver for Digital Beamforming Applications. (Electronic Thesis or Dissertation). Retrieved from https://etd.ohiolink.edu/

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Alwan, Elias. "Ultra-Wideband On-Site-Coding-Receiver for Digital Beamforming Applications." Electronic Thesis or Dissertation. Ohio State University, 2014. OhioLINK Electronic Theses and Dissertations Center. 25 Sep 2017.

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Alwan, Elias "Ultra-Wideband On-Site-Coding-Receiver for Digital Beamforming Applications." Electronic Thesis or Dissertation. Ohio State University, 2014. https://etd.ohiolink.edu/

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