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 20 of 33 for “"Frequency division multiple access"”.
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Opportunistic resource allocation and relaying methods for quality of service in the downlink of future cellular wireless networks
… brink of a major change. New technologies called multiple antenna systems (MIMO) and orthogonal frequency division multiple access (OFDMA) will be put together in the deployment of the next generation of cellular standards known as 4G. Consumers can expect peak data rates up to 160 Mbps. If the …
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Deep learning for energy-efficient wireless communications and spectrum management.
… system: a multiuser downlink Orthogonal Frequency Division Multiple Access data transmission system. In the system, the base station aims to achieve the highest communication quality with the least energy consumption. Deep Learning algorithms are applied to accomplish the energy-efficient …
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PAPR reduction in OFDM communications with generalized discrete Fourier transform
… One of the main drawbacks of Orthogonal Frequency Division Multiplexing (OFDM) systems is the high Peak to Average Power Ratio (PAPR) value which is directly related to power consumption of the system. Discrete Fourier Transform (DFT) spread OFDM technology, also known as Single Carrier …
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Sistemas de transmissão multiportadora aplicados em um canal acústico submarino na presença de efeito doppler
… Such analysis encompass (Single-Carrier Frequency Division Multiple Access) SC-FDMA, (Orthogonal Frequency Division Multiplexing) OFDM and (Frequency Shift Keying) FSK systems, with either Zero Forcing (ZF) or minimum mean-square error (MMSE) equalizers. We investigate system performance …
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Analysis and mitigation of carrier frequency offset for uplink of OFDMA
Orthogonal Frequency Division Multiplexing (OFDM) is being used in many wireless standards because of its immunity to multipath fading, high spectral efficiency and simple implementation, making it suitable for high data rate multimedia wireless applications. One of the significant drawbacks of the …
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Iterative detection for overloaded OFDMA with spatial diversity
Orthogonal Frequency Division Multiple Access (OFDMA) systems have built-in mechanisms to mitigate the effects of the wireless multipath channel but are limited in system capacity to available bandwidth. This shortcoming can be worked around through the process of "overloading," where users are …
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Cross-Layer Capacity Optimization In OFDMA Systems: WiMAX And LTE
… such as wireless interoperability for microwave access (Wimax) and long term evolution (lte) adopted by international standards. This thesis considers orthogonal frequency division multiple access (ofdma) system, which has been implemented in both Wimax and lte technologies as their air interface …
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Spectrum Awareness: Deep Learning and Isolation Forest Approaches for Open-set Identification of Signals
… solutions to current limitations by allowing access to bands previously unavailable to civilian communication networks. However, this also provides new challenges primarily for the military operations. Radar bands have traditionally operated primarily in the sub-6 GHz region. In the past, …
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Simulation Study of Local Multipoint Distribution Service
… to examine the performance of two different multiple access schemes and two different duplexing schemes. LMDS is a broadband wireless point-to-multipoint access network that aims to improve network access capacity for end-users by solving the "last mile" problem. This study involves building …
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Enabling decentralized wireless index coding in practice
… the optimal coding scheme for transmitting multiple messages across a network to receivers with different side information. The ultimate goal of index coding is to reduce transmission time in a communication network by minimizing the number of messages based on shared information. Index …
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Optimal resource allocation In base stations for mobile wireless communications
… when mobile base stations have an Orthogonal Frequency-Division Multiple Access (OFDMA) architecture, where there are subcarriers for data transmission and users with various transmission demands. In such systems, we simultaneously allocate subcarriers to users and power to subcarriers, …
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Optimum linear single user detection in direct-sequence spread-spectrum multiple access systems
… proposal of the IS-95 standard, <i>code-division multiple access</i> (CDMA) gained popularity as an alternative multiple-access scheme in cellular and <i>personal communication systems</i> (PCS). Besides the advantage of allowing asynchronous operation of the users, CDMA …
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Design of the control systems operations for the Iridium satellite system
… Speciale Mobile (GSM), a combination of time division mUltiple access, TDMA, and frequency division multiple access, FDMA, is recommended for use by Iridium. A bus topology with a fiber backbone is suggested to support the operations at each facility and a separate landline is considered to …
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Statistical delay QoS driven resource allocation and performance analysis for wireless communication networks
… limit, in a multi-user multi-carrier orthogonal frequency-division multiple access (OFDMA) system, is proposed and analyzed. Formulated as a combinatorial integer programming problem, the problem is decoupled into a frequency provisioning problem and an independent per-user multi-carrier EE-EC …
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Optimisation and algorithms in wireless networks for mission critical applications
… of two interfering users in an Orthogonal Frequency Division Multiple Access (OFDMA)-based cooperative base stations and (b) event-region detection in Wireless Sensor Networks (WSNs). The first area of work makes contribution on problem of maximising the sum rate of two interfering users, …
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A variable-rate modulation and coding scheme for low earth orbit satellites
… of approximately 50kbps transmission in a 10kHz Frequency Division Multiple Access (FDMA) channel it was necessary to consider spectrally efficient, rather than power efficient, modulations. The proposed modulation scheme makes use of an eight-dimensional trellis coded modulation system. Multiple …
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Inter-cell interference mitigation in LTE-advanced heterogeneous mobile networks
… networks, as an example of OFDMA (orthogonal frequency division multiple access)-based networks. More attention is paid to the Pico cell as an important cell type in heterogeneous deployment, due to the direct backhauling with the macro cell to coordinate the resource allocation among cells …
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Reducing Multiple Access Interference in Broadband Multi-User Wireless Networks
<p>This dissertation is devoted to developing multiple access interference (MAI) reduction techniques for multi-carrier multi-user wireless communication networks.</p> <p>In multi-carrier code division multiple access (MC-CDMA) systems, a full multipath diversity can be achieved by transmitting one …
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Analysis of Jamming-Vulnerabilities of Modern Multi-carrier Communication Systems
… multi-carrier communication systems, Orthogonal Frequency Division Multiplexing (OFDM) and Single-Carrier Frequency Division Multiple Access (SC-FDMA). In order to lay the necessary theoretical groundwork, first we derived the analytical BER expressions for BPSK/QPSK and analytical upper and …
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Radio Resource Management in 5G Cellular Networks
… the analysis provided considers different frequency band, like the mmWave transmissions and the sub-6GHz transmissions, different access techniques, like Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA) and the novel Sparse Code Multiple Access …
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