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Electrical and Electronics

Air Force Institute of Technology

Wireless communication systems

Publication Year

Articles 1 - 3 of 3

Full-Text Articles in Engineering

Toward A Mobile Agent Relay Network, Hyon H. Kwak Mar 2010

Toward A Mobile Agent Relay Network, Hyon H. Kwak

Theses and Dissertations

Although wireless communication provides connectivity where hardwired links are difficult or impractical, it is still hindered by the environmental conditions where the communicators reside. Signal loss over large distances or because of intervening obstacles can be mitigated by increasing the user's transmission power or adding repeater nodes between the users. Unfortunately, increasing the signal strength strains limited power resources and increases the likelihood of eavesdropping. Stationary repeaters are impractical for highly mobile users in dangerous environments. While mobile relay nodes might be a preferred solution, a centralized control scheme saps bandwidth from important traffic and introduces a single point of …


Spectral Domain Rf Fingerprinting For 802.11 Wireless Devices, Sheldon A. Munns Mar 2010

Spectral Domain Rf Fingerprinting For 802.11 Wireless Devices, Sheldon A. Munns

Theses and Dissertations

The increase in availability and reduction in cost of commercial communication devices (e.g. IEEE compliant such as 802.11, WiFi, 802.16, Bluetooth etc.) has increased wireless user exposure and the need for techniques to properly identify/classify signals for increased security measures. Communication device emissions include intentional modulation that enables correct device operation. Hardware and environmental factors alter the ideal response and induce unintentional modulation effects. If these effects (features) are sufficiently unique, it becomes possible to identify a device using its fingerprint, with potential discrimination of not only the manufacturer but possibly the serial number for a given manufacturer. Many techniques …


Ultra Wide Band Multiple Access Performance Using Th-Ppm And Ds-Bpsk Modulations, Courtney M. Canadeo Mar 2003

Ultra Wide Band Multiple Access Performance Using Th-Ppm And Ds-Bpsk Modulations, Courtney M. Canadeo

Theses and Dissertations

The increasing demand for portable, high data rate communications has focused much attention on wireless technology. Ultra Wide Band (UWB) waveforms have the ability to deliver megabits of information while maintaining low average power consumption. In accordance with recent FCC ruling, UWB systems are now allowed to operate in the unlicensed spectrum of 3.1 to 10.6 GHz, motivating renewed interest in the forty year old concept of impulse radio. Gaussian monocycles produce UWB waveforms occupying large bandwidths with multiple access (MA) capability enabled by spread spectrum techniques. Time Hopping (TH) and Direct Sequence (DS) modulations are considered here for UWB …