Vahid Dehghanian

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The combined spatial-polarization correlation function for indoor multipath environments is discussed. An analytical model based on an isotropic receiving antenna and a sphere of scatterers is developed for quantifying signal decorrelation as a function of antennas’ spatial and orientation separation. A closed form expression is deduced for the combined(More)
A novel fast and accurate interpolation technique for recovering the uniformly distributed samples from the irregularly spaced samples, collected non-uniformly due to the probe position error in planar near-field antenna measurements, is presented. The technique employs Yen’s interpolator and tries to make it as practical as possible for the use in(More)
Size and cost considerations of handheld terminals limit the use of antenna array for combating multipath fading in these applications. Recently, a synthetic array based on moving a single antenna was proposed for handheld terminals. This technique however fails to provide enough diversity gain when the channel is spatially correlated. A combination(More)
A novel technique for synthesizing an array of antenna elements with multiple polarization characteristics based on angular movements of a single antenna is developed. The diversity performance of the synthesized antenna array is then compared to that of a single static antenna through an extensive set of measurements based on capturing the CDMA 2000(More)
Size and cost considerations of handheld terminals limit the use of antenna array for combating multipath fading in these applications. Recently, a synthetic array based on moving a single antenna was proposed for handheld terminals. This technique however fails to provide enough diversity gain when the channel is spatially correlated. A combination(More)
A novel configuration for improving the frequency tracking performance of GNSS signals in multipath environments is proposed. The proposed technique is based on combining the weakly correlated outputs of Early, Prompt and Late match filters to exploit the inherent time-delay diversity when severe multipath conditions prevail. By observing more code-phase(More)
In this paper we investigate the impact of user proximity to handheld antenna on the performance of RSS-based indoor positioning. A planar inverted-F antenna (PIFA) is designed for operation in 2.4 GHz and the changes in antenna characteristics due to proximity to human head are quantified using a commercial full-wave simulation software. Large variation in(More)
The performance of code delay and carrier phase estimation of a GNSS signal propagated in an urban or indoor environment is highly degraded by multipath when the conventional multipath mitigation techniques such as narrow correlator and double delta correlator are applied. These conventional techniques rely on the value of the delay corresponding to the(More)