Analysis and Mitigation of Tropospheric Effects on Ka Band Satellite Signals and Estimation of Ergodic Capacity and Outage Probability for Terrestrial Links
Mar 22, 2012
from 02:00 PM to 04:00 PM
|Where||ENGR. IV Bldg. Maxwell Room 57-124|
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Advisor: Michael P. Fitz
The first part of this work covers the effect of the troposphere on Ka band (20-30 GHz) satellite signals. The second part deals with the estimation of the capacity and outage probability for terrestrial links when constrained to quadrature amplitude modulations (QAM). The desire for higher data rates and the need for available bandwidth has pushed satellite communications into the Ka band (20-30 GHz). At these higher carrier frequencies the effects of scintillation and rain attenuation are increased. In regards to the effects of scintillation, the first part of this work quantifies, through the use of a multiple phase screen simulation model, the benefits of using two receive antennas to mitigate tropospheric-induced scintillation on Ka band satellite downlinks. In regards to rain attenuation, this work developed a simple method for efficiently estimating the outage probability, outage capacity and ergodic capacity of satellite links due to rain fades. In addition, this portion of the work quantifies the benefit of using receive diversity to mitigate rain fades.
The second part of this work examines terrestrial communication links with either Rayleigh distribution or the log-normal fading. The goal of this second part of the work was to develop a simple method for tightly estimating the ergodic capacity and outage probability of these two channel types when used with QAM signalling sets. Specifically an innovative method was developed for estimating the ergodic constrained capacity for Rayleigh and log-normal channels with and without antenna combining. The expressions facilitate straightforward computation of outage probability as well. Both the noise-limited and interference-limited cases are studied. To date, no other method for estimating the outage probabilities for the constrained capacity of Rayleigh or log-normal channels has been published for either the noise-limited case or interference-limited case. The analysis methods and information for terrestrial links developed in the second part of this work provide useful tools for the designers of wireless communication systems in general and have particular application to cellular mobile and ultra-wideband systems.
Scott Enserink has 19 years of experience in wireless communications designing software definable radios and high-speed reconfigurable modems at Motorola, Intersil, and, currently, at Northrop Grumman. He is a PhD candidate at UCLA, specializing in the modeling of satellite and terrestrial channels.