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 41 for “"OFDMA"”.
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Distributed Multiple Access for OFDMA Femtocells
… serves as a strong motivation for the design of OFDMA-aware random 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 …
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Indoor Positioning Using Synchronized Ultrasonic OFDMA Signals
… in an Orthogonal Frequency Multiple Access (OFDMA) scheme. This indoor positioning system (IPS) operates at an ultrasonic frequency of approximately 40kHz and synchronizes using an infrared signal. The OFDMA scheme allows for a receiver to process the signals from multiple transmitters …
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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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Resource allocation for multi-cell OFDMA based cooperative relay network
… to study the resource allocation algorithm for OFDMA based cooperative relay networks with more realistic assumptions. This thesis focuses on the resource allocation for the uplink OFDMA based cooperative relay networks. Multiple cells were considered, each composed of a single base station …
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Cross-Layer Capacity Optimization In OFDMA Systems: WiMAX And LTE
… orthogonal frequency division multiple access (ofdma) system, which has been implemented in both Wimax and lte technologies as their air interface multiple access mechanism. A framework for optimized resource allocation with quality of service (qos) support that aims to balance between service …
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Analysis and mitigation of carrier frequency offset for uplink of OFDMA
… Orthogonal Frequency Division Multiple Access (OFDMA). However, calculation of MUI power required in this algorithm for all users impose very high computational burden on the receiver. In the proposed Low Complexity MUI Suppression by MMSE Equalization for Uplink of OFDMA approximation to the …
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A Joint Optimization Approach for Power-Efficient Heterogeneous OFDMA Radio Access Networks
L'abstract è presente nell'allegato / the abstract is in the attachment
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Adaptive radio resource management schemes for the downlink of the OFDMA-based wireless communication systems
… suitable for high speed mobile wireless systems OFDMA has been adopted by next generation broadband wireless standards including Worldwide Interoperability for Microwave Access (WiMAX) and Long Term Evolution – Advanced (LTE-A). Intelligent and adaptive Radio Resource Management (RRM) schemes are …
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Enabling decentralized wireless index coding in practice
… how index coding can be applied to an OFDMA downlink network during the retransmission phase. An orthogonal frequency-division multiple access (OFDMA) downlink network is a network where data is sent downward from a designated higher-level transmitter to a group of receiving nodes. In …
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Radio Resource Allocation in Wireless OFDM Systems
… (SBPA) problem in single-cell and multi-cell OFDMA systems which can be formulated as mixed integer nonlinear programming (MINLP) is generally highly complex. We proposed methods to convert MINLP to binary linear programming (BLP) which are linear and much easier to solve. We use the optimal …
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Optimización algorítmica orientada a la implementación en dispositivos reconfigurables de esquemas multiestándar y multiusuario para sincronismo de frecuencia en sistemas de comunicaciones inalámbricas basados en OFDM
… sistemas OFDM, multiestándar OFDM y multiusuario OFDMA. El objetivo de esta Tesis es la de proponer esquemas de sincronización con menor coste computacional que los métodos ya existentes para facilitar su implementación en dispositivos reconfigurables, como son las FPGAs. Por ello, además, se …
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Opportunistic resource allocation and relaying methods for quality of service in the downlink of future cellular wireless networks
… 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 user is to have a good network experience with multimedia applications, then …
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Capacity, coding and interference cancellation in multiuser multicarrier wireless communications systems
… Orthogonal Frequency Division Multiple Access (OFDMA), a flexible orthogonal multiplexing scheme that can implement time and frequency division multiplexing, and using multicarrier code division multiple access (MC-CDMA). Coding, interference cancellation, and resource sharing schemes to improve …
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Optimisation and algorithms in wireless networks for mission critical applications
… 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, while limiting the received …
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NS-3 Simulation of WiMAX Networks
… model to provide analysis on a new WiMAX OFDMA downlink subframe mapping algorithm.
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Improving Throughput and Efficiency for WLAN: Sounding, Grouping, Scheduling
… orthogonal frequency-division multiple access (OFDMA), which will be the key enabler to maximize spectrum utilization in the next generation of WLAN, IEEE 802.11ax. An unsolved problem for 802.11ax is maximizing the number of satisfied users in the OFDMA system while accommodating the different …
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Radio Resource Management in 5G Cellular Networks
… Orthogonal Frequency Division Multiple Access (OFDMA) and the novel Sparse Code Multiple Access (SCMA), the support of advanced radio access technologies, such as beamforming technique and device-to-device (D2D) communications, the definition of very simple random access procedure to meet the …
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Optimal resource allocation In base stations for mobile wireless communications
… 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, subject to various constraints including …
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MAC layer resource allocation algorithms for OFDM/TDMA wireless networks
In wireless networks employing OFDMA/TDMA, orthogonal channels and timeslots are available resources that should be distributed between users fairly and in a collision-free manner. Furthermore, the available resources should be used efficiently. In this dissertation, the resource allocation …
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Packet Scheduling for LTE-Advanced
… use the same air-interface technologies such as OFDMA, MIMO, and the same core network. Since radio spectrum is the most valuable resource in mobile technology, radio resource management (RRM) mechanisms are critical for the operation of a cellular network. One of the key RRM mechanisms is packet …
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