Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"antenna diversity"”.
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Weak GPS Signal Acquisition Using Antenna Diversity
… ratio (C/N0) varies significantly. Spatial antenna diversity provides additional processing gain to overcome multipath fading since multiple antennas detect signal components from independent fading channels. This thesis evaluates equal gain combining of two independent antennas in a …
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Control of an indoor autonomous mobile communications relay via antenna diversity
… controller presented here is driven by antenna diversity and attempts to optimize the inputs to an unknown, time-varying cost function characterized by the RF environment. Each of the multiple antennas onboard the quadrotor receives the same incoming packets and provides associated …
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Small scale antenna diversity as a means of reducing the effects of multipath fading for handheld satellite communications systems
… communications system using an omni-directional antenna. A significant finding was that motion of the satellite could induce fades of up to lOdB, well in excess of the small link margins available to satellite-to-handheld systems (typically ≤ 3dB). A method for ameliorating multi path fading was …
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Effects of user and spatial diversity on high data rate wireless systems
… that can support the best rate. In contrast, antenna diversity, where multiple antennas are deployed at the receiver or transmitter; has the effect of improving received signal fidelity by averaging the channel variation. In this thesis, we evaluate the joint effect of user diversity and …
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Detection and Coding Techniques for Fourth Generation Air-Interfaces based on Multicarrier Modulation
… that, though MC-CDMA benefits from frequency diversity even in the absence of channel coding and antenna diversity, MC-DS-CDMA performs better than MC-CDMA with channel coding and antenna diversity. MC-CDMA becomes subject to MAI enhancement in frequency selective fading channels. To reduce …
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Capacity-approaching data transmission in MIMO broadcast channels
This dissertation focuses on downlink multi-antenna transmission with packet scheduling in a wireless packet data network. The topic is viewed as a critical system design problem for future high-speed packet networks requiring extremely high spectral efficiency. Our aim is to illustrate the …
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Efficient Interference Cancellation Techniques for Advanced DS-CDMA Receivers
… of the non-coherent approach. Additionally, dual-antenna diversity techniques are also investigated as a means for improving performance in multipath environments.
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Digital video transmission over wireless networks
… Typical anti-multipath techniques, such as antenna diversity, are deployed to mitigate the effects of the channel. Link layer error control techniques are also investigated.
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Radio Channel Measurements and Modeling for Smart Antenna Array Systems Using a Software Radio Receiver
… wave propagation measurement and modeling, smart antenna arrays, and software-defined radio development. A four-channel, wideband, software-defined receiver was developed to serve as a test bed for wideband measurements and antenna array experiments. This receiver was used to perform vector …
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3.5 GHz Indoor Propagation Modeling and Channel Characterization
… for multipath analysis. The statistical multi-antenna diversity gain was evaluated to gauge the benefit of using multi-antenna systems in an indoor environment, which has much greater spatial diversity than an outdoor environment. Measurements were compared to indoor path loss models used for …
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Error relilient video communications using high level M-QAM. Modelling and simulation of a comparative analysis of a dual-priority M-QAM transmission system for H.264/AVC video applications over band-limited and error-phone channels.
… will yield a better performance. Additionally, antenna diversity techniques are examined and introduced to the transmission system that can offer a significant improvement in the quality of service of mobile video communication systems in environments that can be modelled by a Rayleigh fading …
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Antenna effects on indoor wireless channels and a deterministic wide-band propagation model for in-building personal communication systems
While the application of antenna diversity in a narrow band communication system is well understood, little research has been done on antenna effects in wide-band channels. Research has shown that circular polarization (CP) is more robust in combating multipath than linear polarization in …
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Analysis of a Two-Branch Maximal Ratio and Selection Diversity System with Unequal Branch Powers and Correlated Inputs for a Rayleigh Fading Channel
… an analytical framework for analyzing two-branch diversity systems for a Rayleigh fading channel. In many cases the fading received at both branches (i.e. a two-antenna element system) is correlated because of the proximity of the antenna elements to each other. It is also not uncommon for a …
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Coordination strategies for connected robotic networks
… Finally in the last chapter of Part I we exploit antenna diversity in a practical case study to localize and improve the signal quality between a mobile agent and a user. In Part II we focus our attention on heterogeneous systems. With the term heterogeneous we imply the synergy of multiple …
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Four Branch Diversity Combining and Adaptive Beamforming Measurements Using Mobile Arrays at 2.05 GHz
Mobile arrays employing diversity combining and adaptive beamforming techniques overcome multipath fading, improve coverage, and increase capacity in wireless communications systems. In this thesis, diversity combining and adaptive beamforming performance of different four element arrays for mobile …
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Near-capacity co-located and distributed MIMO systems
… types of fundamental gains, when using multiple antennas in wireless communications systems: the multiplexing gain and the diversity gain. Spatial multiplexing techniques such as the Vertical Bell-labs LAyered Space-Time (V-BLAST) scheme exploit the associated multiplexing gain in terms of an …
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Synthesis of Optimal Arrays For MIMO and Diversity Systems
… proposes a method for determining the optimal antenna element radiation characteristics which maximize diversity gain given a specific power angular spectrum of the propagation environment. The method numerically constructs the eigenfunctions of the covariance operator for the scenario subject …
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Channel Probing for an Indoor Wireless Communications Channel
… used to simulate the performance of spatial diversity in receive antenna configurations. The model presented by Saleh and Valenzuela, was added to by Spencer et. al., and included all three of these parameters for a 7 GHz channel. A system was built to measure these multipath parameters at …