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 153 for “"Spectral efficiency"”.
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Spectrum sharing systems for improving spectral efficiency in cognitive cellular network
… channels to secondary users to maximize the spectral efficiency. The function of the DFC is formulated as an optimization problem with the objective of maximizing the spectral efficiency. The optimal detection threshold is obtained for different cases with various spatial densities of ZAs and …
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Spectral efficiency optimization with channel state information of a massive MIMO System
… (CSI) in a wireless system. To optimize the spectral efficiency of imperfect CSI, an algorithm called penalty dual decomposition (PDD) is proposed for these problems. The PDD is a double-loop iterative algorithm that has a guaranteed convergence to Karush-Kuhn-Tucker (KKT) solution of the …
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Optimising energy efficiency and spectral efficiency in multi-tier heterogeneous networks : performance and tradeoffs
… the design of future generation networks. The spectral efficiency (SE) can be improved by better utilisation of the network resources at the cost of reduction in the energy efficiency (EE) due to the enormous increase in the network power expenditure arising from the densification of the …
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Enabling rApp in 5G O-RAN: An Spectral Optimization (SO)rApp Use Case
… onboarding to deployment and execution, using a spectral efficiency op- timization use case to illustrate the process. The study develops and integrates a Spectrum Optimization (SO)rApp employing Reinforcement Learning (RL) techniques, specifically a Deep Q-Network (DQN) model, within the O-RAN …
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Performance evaluation of massive MIMO Systems for future wireless access systems
… has been proposed. Massive MIMO improves both spectral efficiency and energy efficiency and is therefore also proposed for spectra below 6GHz. This study focuses on assessing the potential of massive MIMO through evaluation of linear precoding and receive combining methods that may be …
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Spectral Shape Division Multiplexing (SSDM): Apparatus, Transmitter, Receiver and Detection
… multiplexing method that saves spectrum called Spectral Shape Division Multiplexing (SSDM). Under certain configurations, SSDM displays higher flexibility and throughput than other spectrally efficient methods.</p> <p>SSDM defines the structure of a wireless multi-carrier by software. It is …
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On enhancing connectivity and efficiency in 5G and emerging 6G mobile networks
… stringent requirements on connectivity, efficiency, reliability, and adaptability, particularly for smart factory and dense urban environments. This thesis investigates key challenges in next-generation wireless systems, including base station selection, interference management, spectral …
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Experimental designs for efficient free-space multi-spatial-mode optical communication
In optical communications, two measures of efficiency are commonly at odds. The first is the photon information efficiency (in bits/photon) which measures the information that each detected photon conveys; the second is the spectral efficiency (in bits/s/Hz) which measures the bit rate achieved …
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Trellis-coded permutation modulation for improved performance of narrowband noncoherent FSK
… shown that FSK permutation modulation has better spectral efficiency than conventional FSK modulation" but with the tradeoff on reduced energy efficiency. To overcome this problem, we apply trellis-coded modulation (TCM) , which is a combined technology of convolutional coding and modulation, to …
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Channel Estimation Overhead Reduction for Downlink FDD Massive MIMO Systems
… In addition, we derive a lower bound on the spectral efficiency of the communication system. Close form expressions of the asymptotic MSE and the spectral efficiency lower bound are obtained. Furthermore, perfect match between theoretical and simulation results is observed, and results show …
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Interference Management in Heterogeneous Cellular Networks
… HetNets including coverage probability and spectral efficiency in mathematical expression, and some insights are revealed on the relationships of interference statistics and network performance with system parameters such as frequency reuse factor, transmission probability, and the …
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Real-time adaptive circuitry to support simultaneous radar and communications.
… missed radar detections. To help mitigate this spectral congestion, this work presents technological innovations to increase spectral efficiency and mobility for radio frequency (RF) systems. Directional modulation (DM) allows an array to perform simultaneous radar and communication operations …
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Orthogonal Frequency Division Multiplexing Modelling
… the channel impairments increased in FBMC. The spectral efficiency of OFDM is higher than FBMC spectral efficiency at low burst durations. High burst duration results in FBMC spectral efficiency getting higher than OFDM spectral efficiency. Mild impairments rarely caused symbol recovery errors, …
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OWSS And MIMO-STC-OFDM: Signaling Systems for the Next Generation of High Speed Wireless LANs
… a testament primarily to their convenience, cost efficiency and ease of integration. Even now the demand for high data rate wireless communications has increased fourfold as consumers demand better multimedia communications over the wireless medium. The next generation of high speed WLANs is …
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SPECTRALLY EFFICIENT MULTICARRIER SYSTEMS FOR FIBER-OPTIC TRANSMISSION
… research is to provide a comprehensive study of spectrally efficient multicarrier systems for fiber-optic transmission. Multicarrier optical systems partition a high-data rate digital signal in a wavelength channel into multiple subcarriers. The data rate on each subcarrier can be sufficiently …
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On the Impact of Channel and Channel Quality Estimation on Adaptive Modulation
… exploits these channel variations to improve the spectral efficiency of wireless communications by intelligently changing the modulation scheme based on channel conditions. Necessarily, among the modulation schemes used are spectrally efficient modulation schemes such as quadrature amplitude …
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Channel Estimation Strategies for Coded MIMO Systems
High transmission data rate, spectral efficiency, and reliability are necessary for future wireless communications systems. In a multipath-rich wireless channel, deploying multiple antennas at both the transmitter and receiver achieves high data rate, without increasing the total transmission power …
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Low-Complexity Iterative Receiver Design for Multi-Carrier Faster-Than-Nyquist Signaling Over Frequency-Selective Fading Channel
… and scarce spectrum resources is to improve the spectral efficiency of wireless communication systems. Multi-carrier faster-than-Nyquist (MFTN) signaling reduces the symbol period satisfying the Nyquist criterion in the time domain and the minimum spacing of orthogonal subcarriers in the …
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Novel DWT-DAPSK based transceivers for DVB-T transmission and next generation mobile networks
… digital communication services with very high spectral efficiency and significantly improved performance. Orthogonal Frequency Division Multiplexing (OFDM) systems have been increasingly deployed in mobile networks for their spectral efficiency and optimum bit error rate. An OFDM system is a …
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Influence of the Number of Degrees of Freedom on the Capacity of Incoherent Optical Fiber Communication Systems
… comparing performance limits. We evaluate both spectral efficiency limits (bps/Hz) in the limit of high and low SNR for the 1,2 and 4 DOF cases and also find the power efficiency (minimum number of photons per bit) for each of these cases. It is shown that for high SNR the spectral efficiency is …
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