Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

2012

Air Force Institute of Technology

Orthogonal frequency division multiplexing

Articles 1 - 3 of 3

Full-Text Articles in Engineering

Passive Synthetic Aperture Radar Imaging Using Commercial Ofdm Communication Networks, Jose R. Gutierrez Del Arroyo Sep 2012

Passive Synthetic Aperture Radar Imaging Using Commercial Ofdm Communication Networks, Jose R. Gutierrez Del Arroyo

Theses and Dissertations

Modern communication systems provide myriad opportunities for passive radar applications. OFDM is a popular waveform used widely in wireless communication networks today. Understanding the structure of these networks becomes critical in future passive radar systems design and concept development. This research develops collection and signal processing models to produce passive SAR ground images using OFDM communication networks. The OFDM-based WiMAX network is selected as a relevant example and is evaluated as a viable source for radar ground imaging. The monostatic and bistatic phase history models for OFDM are derived and validated with experimental single dimensional data. An airborne passive collection …


Ofdm-Based Signal Exploitation Using Quadrature Mirror Filter Bank (Qmfb) Processing, Felipe E. Garrido Mar 2012

Ofdm-Based Signal Exploitation Using Quadrature Mirror Filter Bank (Qmfb) Processing, Felipe E. Garrido

Theses and Dissertations

By performing QMFB processing with a given signal it is possible to obtain Frequency-Time (F-T) outputs that represent signal features such as bandwidth (W), center frequency (fc), signal duration (Ts), modulation type (AM, FM, BPSK, QAM, etc), frequency content and time allocation. Because of its unique structure, two widely used signals based on Orthogonal Frequency Division Multiplexing (OFDM) were chosen as signals of interest for demonstration. The general implementation of the QMFB process is described along with the basic structure of OFDM signals related to the physical layer perspective of 802.11a Wi-Fi and 802.16e WiMAX frame structures are described. The …


Passive Multistatic Radar Imaging Using An Ofdm Based Signal Of Opportunity, Matthew B. P. Rapson Mar 2012

Passive Multistatic Radar Imaging Using An Ofdm Based Signal Of Opportunity, Matthew B. P. Rapson

Theses and Dissertations

This paper demonstrates a proof of concept in using an OFDM-based signal of opportunity for SAR imaging purposes within a passive, multistatic radar construct. Two signal processing methods have been proposed to create phase history data. The same methods are applied in both a simulated software model and an experimental data collection environment to produce simulated SAR images using the CBP imaging algorithm. The images generated from both the experimental and simulated data were observed to be consistent with each other and with expectations in terms of resolution. Coherent addition of the images results in improved image resolution due to …