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 17 of 17 for “"frequency diversity"”.
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Detection and Coding Techniques for Fourth Generation Air-Interfaces based on Multicarrier Modulation
… on multicarrier modulation. Two joint Orthogonal Frequency Division Multiplexing (OFDM) and Code Division Multiple Access (CDMA) schemes have been characterised and compared in respect of their performance in different environments and configurations. The first scheme is Multicarrier Direct …
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Multi-layered Space Frequency Time Codes
… that combine spatial multiplexing and transmit diversity. Each layer consists of a space time code. The detection algorithms are based on multi-user detection theory. We consider joint, interference nulling and cancellation, and spatial sequence estimation algorithms. As part of joint detection …
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Wideband Terrestrial Path Loss Measurement Results For Characterization of Pico-cell Radio Links at 38 GHz and 60 GHz Bands of Frequencies
… compared with popular rain models. Results from Frequency Diversity measurement campaigns are also presented.
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Coherence bandwidth characterisation for indoor mobile radio microcells at microwave and millimetre wave frequencies
… has been investigated.<br/><br/>A two branch frequency diversity system has been developed and used to simultaneously record the amplitude variation of the sideband signals. Frequency separations in the range between 5 and 240 MHz have been used at both 11 GHz and 62.4 GHz. In order to assist …
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Channel estimation for Gigabit Multi-user MIMO-OFDM Systems
… schemes can be further improved using space-frequency diversity techniques, for example, when multiple-input multiple-output (MIMO) antenna technologies are employed in conjunction with Orthogonal Frequency Division Multiplexing (OFDM).However, the superior performance promised by the …
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Real-time sub-carrier Adaptive Modulation and Coding in wideband Orthogonal Frequency Division Multiplexing wireless systems
… Modulation and Coding (AMC) exploits the high frequency diversity in wideband Orthogonal Frequency Division Multiplexing (OFDM) channels to obtain higher data rates. While prior work has discussed the value of sub-carrier AMC from a theoretical perspective, this work presents the design and …
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Multi-channel ultra-low-power receiver architecture for body area networks
… ISM bands, it is important to employ multiple frequency channels to permit frequency-division-multiplexing and provide frequency diversity in the face of narrowband interferers. The high-Q nature of the resonators means that frequency tuning to other channels in the same band is nearly …
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Improved Localization Algorithms in Indoor Wireless Environment
… (RSS) from reference nodes, and utilizing frequency diversity in Wireless Fidelity (WiFi) environment. Deployments of reference nodes are vital for locating nearby targets since they are used to estimate the distances from them to the targets. A reference nodes’ placement scheme based on …
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A comparison of processing approaches for distributed radar sensing
… can take advantage not only from the angular diversity in observing the target, but also from a variety of ways of processing the received signals. The number of devices comprising the network has also been taken into the analysis. Detection and false alarm are evaluated in noise only and …
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Multicarrier Wireless Systems with Adaptive Decision Combining
Multicarrier Orthogonal Frequency Division Multiplexing (OFDM) systems with decision combining are considered in this thesis. It is shown that such systems can provide enhanced bit error rates. However, this occurs at the cost of data throughput of the system. The typical system considered …
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Sport Involvement for Youth with Autism Spectrum Disorders and Intellectual Disabilities
… 1 examined characteristics of sport involvement (frequency, diversity, positive social experiences [PSE]) for youth with intellectual disability (ID) alone compared to youth with ASD+ID and explored the personal and contextual correlates of involvement. Parents (N = 409) of youth involved in …
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Adaptive OFDM Radar for Target Detection and Tracking
… track targets by employing a wideband orthogonal frequency division multiplexing: OFDM) radar signal. The frequency diversity of the OFDM signal improves the sensing performance since the scattering centers of a target resonate variably at different frequencies. In addition, being a wideband …
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Adaptive MIMO Radar for Target Detection, Estimation, and Tracking
… Distributed MIMO radar exploits spatial diversity by utilizing multiple uncorrelated looks at the target. Colocated MIMO radar systems offer performance improvement by exploiting waveform diversity. Each antenna has the freedom to transmit a waveform that is different from the waveforms …
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Viability of High Availability Kband Satellite Communication using Hybrid Fade Mitigation
… capable of simulating the effect of site diversity with a single time series of attenuation and a dual-channel protocol structure that is able to increase availability of control information at V band.<br/><br/>The near-optimum short-term fade predictor is compared with several other …
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Adaptation For Multi-Antenna Systems
… energy efficiency in the presence of unoccupied frequency bands and on spectrally efficient operation under static frequency assignment. Utilizing minimum Euclidean distances of MoDem constellations and the minimum free Hamming distance metrics for channel codes, we develop distance metrics to …
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Distributed Multiple Access for OFDMA Femtocells
… access protocols that utilize the inherent frequency diversity of OFDMA to improve the MAC performance. Next, we analyze OFDMA-Aloha which is the simplest protocol that utilize the frequency-dimension in OFDMA to improve random access performance. The protocol attempts to reduce the packet …
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Waveform design and processing techniques in OFDM radar
… OFDM waveforms instead of the classic linear frequency mod- ulated waveforms. Being a wideband signal, the OFDM symbol offers spectral efficiency along with improved range resolution, two enticing characteristics for radar. Historically a communication signal, OFDM is a special form of multi- …