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 “"Amplify-and-Forward"”.
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Performance Evaluation and Improvement of Wireless Amplify-and-Forward Cooperative-Based Systems under Nodes Mobility and Imperfect CSI Estimation Impacts
… multiple users (via relays) to assist a source forwarding its data to a final destination. Cooperative communication techniques have shown their capability in improving system reliability and extending coverage area, and hence, it is believable that they will act as a promising technology for …
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Cooperative Strategies for Near-Optimal Computation in Wireless Networks
Computation problems, such as network coding and averaging consen- sus, have become increasingly central to the study of wireless networks. Network coding, in which intermediate terminals compute and forward functions of others’ messages, is instrumental in establishing the capacity of multicast …
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Channel estimation in a two-way relay network
… with the help of a relay applying the amplify-and-forward (AF) relaying scheme. The training based channel estimation technique is applied to the proposed network where the numbers of the training sequence transmitted by the two transceivers, are different. All three terminals are …
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A hybrid relaying protocol for the parallel-relay network
… demonstrating that gains are achieved when a random subset of relays is selected. We derive threshold values for the received signal-to-noise ratios (SNRs) at the relays based on outage probabilities; these thresholds essentially determine the active subset of relays in each time frame for our …
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Resource allocation for multi-cell OFDMA based cooperative relay network
… used to assist in communication between sender and receiver. In order to maximise their performance, networks which employ RSs require a new resource allocation and optimisation technique, which takes the RSs into account as a new resource. Several proposals have been presented for the purpose …
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Outage performance of cooperative cognitive relay networks
… to the growing scarcity of radio spectrum and the increased demand for wireless services. Cooperative relay networks can help cognitive radios to improve their utilisation by reducing their transmit power. This allows a reduction in their interference footprint and increases their …
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Differential modulation and non-coherent detection in wireless relay networks
… issues related to differential modulation and non-coherent detection in cooperative networks. Specifically, the thesis examines the behavior and robustness of non-coherent detection in mobile environments (i.e., time-varying channels). The amount of channel variation is related to the …
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Codebook design for distributed relay beamforming system
In FDD amplify-and-forward distributed relay network, codebook techniques are utilized to feedback quantized CSI with limited cost. First, this thesis focuses on the phaseonly codebook and with-power-control codebook design methods under individual relay power constraints. Phase-only codebooks can …
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Asynchronous bi-directional relay-assisted communication networks
… consisting of two singleantenna transceivers and multiple single-antenna relays, where the transceiver-relay paths are subject to different relaying and/or propagation delays. Such a network can be viewed as a multipath channel which can cause inter-symbol-interference (ISI) in the signals …
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Energy-efficient relay cooperation for lifetime maximization
… in a dual-hop relay network operated by amplify-and-forward relays with battery limitations. Power allocation algorithms are proposed for three different scenarios. First, we study the relay cooperation case where all the relays jointly support transmissions for a targeted data rate. By …
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Design, Implementation and Characterization of a Cooperative Communications System
… of techniques which seek to improve reliability and throughput in wireless systems by pooling the resources of distributed nodes. While cooperation can occur at different network layers and time scales, physical layer cooperation at symbol time scales offers the largest benefit. However, symbol …
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Communications over fading channels with partial channel information : performance and design criteria
… results are provided for independent and identically distributed (i.i.d.) Gaussian signals. A simple, low-duty-cycle signaling scheme is proposed to improve the information rates for low signal-to-noise ratio (SNR), and the optimal duty cycle is expressed as a function of the fading …
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Joint relay beamforming and transceiver processing in multiuser relay network
… this thesis, we focus on joint relay beamforming and transceiver processing in multiuser relay network. First of all, we consider the scenario in which multiple source-to-destination (S-D) pairs intend to communicate with the help of multiple distributed amplify-and-forward (AF) relays. A rank-two …
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Wireless transmission with energy harvesting and storage
… systems equipped with energy harvesting devices and finite-capacity batteries. The methods are proposed for the unbounded fading environment. Due to the time-dependent and random behavior of the energy arrival and fading, this dissertation focuses on the stochastic optimization problem to …
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Power efficient designs for 5G wireless networks
In this dissertation, to step forward towards green communication, we study power efficient solutions in three potential 5G wireless networks, namely an asynchronous multicarrier two-way Amplify-and-Forward (AF) relay network, a multi-carrier two-way Filter-and-Forward (FF) network, and a massive …
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Multi-antenna relay network beamforming design for multiuser peer-to-peer communications.
… with multiple multiantenna relays which employ amplify-and-forward relaying protocol. Assuming distributed relay beamforming strategy, we investigate the design of each relay processing matrix to minimize the per-antenna relay power usage for given users’ Signal-to-Noise Ratio (SNR) targets. As …
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Joint channel pairing and power allocation optimization in two-way multichannel relaying.
We consider two-way amplify-and-forward relaying in a multichannel system with two end nodes and a single relay, using a two-slot multi-access broadcast (MABC) as well as time-division broadcast (TDBC) relaying strategies. We investigate the problem of joint subchannel pairing and power allocation …
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Sum-rate optimal network beamforming and power allocation for single-carrier asynchronous bidirectional relay network
… with the help of multiple single-antenna amplify-and-forward (AF) relays. We assume that the network is asynchronous meaning that different transceiver-relay links cause significantly different propagation delays in the signal they convey. As a result, the end-to-end channel is not …
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Adaptive signal combining and detection in cooperative wireless networks
… were developed for multiuser detection and signal combining in cooperative wireless networks. Some of the key contributions and works of this research thesis are: 1. A computationally simple Adaptive Minimum Mean Square Error Multiuser Detection scheme was proposed to eliminate multiple …
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