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 16 of 16 for “"Orthogonal Frequency-Division Multiple Access (OFDMA)"”.
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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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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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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
… arise 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 …
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Statistical delay QoS driven resource allocation and performance analysis for wireless communication networks
… power 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 …
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Optimisation and algorithms in wireless networks for mission critical applications
… rate maximisation 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 …
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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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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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Capacity, coding and interference cancellation in multiuser multicarrier wireless communications systems
… a great deal of research during the last decade. Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation generated with the inverse Discrete Fourier Transform, which has been adopted for standards in wireless and wire-line communications. Multiuser wireless systems using …
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Exploiting Spatial Degrees-of-Freedom for Energy-Efficient Next Generation Cellular Systems
… efficiency. For unequal power allocation of orthogonal frequency division multiplexing (OFDM), the drain efficiency of the PA is determined by the PAPR and hence by the power distribution. This research proposes a PAPR-aware energy-efficient resource allocation scheme for joint orthogonal …
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Packet scheduling algorithms in LTE systems
… quality of service in communication. LTE employs Orthogonal Frequency Division Multiple Access (OFDMA) to simultaneously deliver multimedia services at a high speed rate. Packet switching is used by LTE to support different media services. To meet the QoS requirements for LTE networks, packet …
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DOCSIS 3.1 cable modem and upstream channel simulation in MATLAB
… increased the signal processing to include frequency diplexers. CATV service providers began to expand the bandwidth of their networks in the late 90’s by switching from analogue to digital technology. In an effort to regulate the manufacturing of new digital equipment and ensure …
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Improving Throughput and Efficiency for WLAN: Sounding, Grouping, Scheduling
… and efficiency. To increase throughput, multiple-input and multiple-output (MU-MIMO) has been adopted in the new generation of WLAN, such as IEEE 802.11ac. MU-MIMO systems exploit the spatial separation of users to increase the network throughput. In an MU-MIMO system, efficient channel …
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Τεχνικές βελτιστοποίησης της ποιότητας των παρεχομένων υπηρεσιών (QoS) με έλεγχο κρίσιμων ηλεκτρικών και ηλεκτρομαγνητικών παραμέτρων στα σύγχρονα ασύρματα τηλεπικοινωνιακά συστήματα
Στην παρούσα διδακτορική διατριβή προτείνονται τεχνικές για την βελτιστοποίηση της ποιότητας των παρεχομένων υπηρεσιών στους χρήστες σύγχρονων ασύρματων τηλεπικοινωνιακών συστημάτων που ως τεχνολογίες πρόσβασης έχουν την πολλαπλή πρόσβαση ορθογωνικής διαίρεσης συχνότητας και την πολλαπλή πρόσβαση …