Graduation Year

2011

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Electrical Engineering

Major Professor

Wilfrido , Ph.D. Moreno

Keywords

communication, Processing, signal

Abstract

Wireless connectivity is becoming an integral part of our society. A new paradigm for

aeronautical data services is beginning to take shape. The advances in signal processing,

rapid prototyping, an insatiable consumer demand for Internet services, increase in aircraft

traffic, aircraft safety, etc., are driving the demand for high speed data services. Programs

led by the National Aeronautics and Space Administration (NASA), the Federal Aviation

Administration (FAA), EUROCONTROL and Networking the Sky for Civil Aeronautical

Communications (NEWSKY) are all looking into aeronautical platforms as part of their

Aeronautical Data Network (ADN). The desire is to provide low delay, cost effective and

high speed data connectivity for aeronautical platforms. The platforms can also be used

as a relay for ground and airborne nodes. Such a capability could potentially provide data

connectivity to remote areas. Most of the current high altitude platforms, i.e., aircraft,

provide data connectivity through a satellite. However, satellite resources are limited and

expensive, and they offer limited data throughput as compared to a terrestrial network. A

potential solution is connectivity to ground stations that can provide high speed physical

layers. Since the frequency spectrum is a valuable estate and needs to be used efficiently,

the use of spectrum efficient techniques are evaluated. This dissertation discusses issues

and challenges for developing a high speed ground based physical layer for aircraft and

proposes a novel solution. A detailed analytical analysis is presented to show the issues

related to aeronautical channel and its impacts to aeronautical communication system.

Specifically, the impact of Doppler shifts that limit the use of efficient modulation schemes,

such as Orthogonal Frequency Division Multiplexing (OFDM), is presented. OFDM is

sensitive to Doppler shifts. In addition, Doppler spread and shifts in aeronautical channels

depict different characteristics compared to terrestrial networks, i.e., multiple Doppler shifts

xi

and delays. Parametric techniques are investigated to accurately estimate the Doppler

shifts. The results of parametric methods for estimating the Doppler shifts are presented.

The simulation results of MUltiple Signal Classification (MUSIC), Eigenvector (EV) and

Minimum norm methods are considered for an aeronautical channel and their performances

is presented.

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