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.
Results
Showing 1 to 20 of 38 for “"spectrum efficiency"”.
-
Spectrum Efficiency and Security in Dynamic Spectrum Sharing
… major paradigm shift in how we manage the radio spectrum. This paradigm shift in spectrum management from exclusive access to shared access is necessitated by the growth of wireless services and the demand pressure imposed on limited spectrum resources under legacy management regimes. The primary …
-
Analysis of Spectrum Efficiency and Energy Efficiency of Heterogeneous Cellular Networks
… While the HetNets are capable of increasing the spectrum efficiency (SE) through higher reuse of the available spectrum, the operation of the BSs comes at a huge increase in the overall network power expenditure, leading to the deterioration of the energy efficiency (EE) performance. For …
-
Efficient radio resource management for future generation heterogeneous wireless networks
… Cognitive Radio (CR) technology with the Dynamic Spectrum Access (DSA) and stochastic process are the key technologies utilized in this research to increase the spectrum efficiency and energy efficiency at limited interference. This thesis essentially investigates three research issues relating to …
-
Phase noise effects on OFDM : analysis and mitigation
… (OFDM) is a promising technique which has high spectrum efficiency and the robustness against channel frequency selectivity. One drawback of OFDM is its sensitivity to phase noise. It has been shown that even small phase noise leads to significant performance loss of OFDM. Therefore, phase noise …
-
Signal conditioning for high efficiency : wireless transmission
… will need wider band-width channels and improved spectrum efficiency to achieve the specified LTE-advanced 100Mbps (mobile) and 1Gbps (fixed) wireless transmission target rate. The next generation of wireless basestations will also need to be powered from renewable sources, particularly in …
-
Longer Term Dynamics of Bit Error Rates using Universal Software Radio Peripheral (USRP) Software Defined Radios for Indoor Environments
… like multipath fading, interference, reduced spectrum efficiency which makes the system less reliable. In our thesis, we made an analysis of performance of different modulation schemes using Software Defined Radios. Software Defined Radios provides inexpensive approach for engineering problems …
-
Simulation of Adaptive Array Algorithms for CDMA Systems
… services without a corresponding increase in RF spectrum allocation motivates the need for new techniques to improve spectrum utilization. The CDMA and adaptive antenna array are two approaches that shows real promise for increasing spectrum efficiency. In this research, we investigate the …
-
ΜΕΛΕΤΗ ΚΑΙ ΥΠΟΛΟΓΙΣΜΟΣ ΤΗΣ ΕΠΙΘΥΜΗΤΗΣ ΠΡΟΠΑΡΑΜΟΡΦΩΣΗΣ ΓΙΑ ΤΗΝ ΔΙΟΡΘΩΣΗ ΤΗΣ ΕΙΣΑΓΟΜΕΝΗΣ ΠΑΡΑΜΟΡΦΩΣΗΣ ΣΕ ΜΗ ΓΡΑΜΜΙΚΟΥΣ ΠΟΛΥΕΠΙΠΕΔΟΥΣ ΨΗΦΙ...
… THE CURRENT TREND IS TO IMPROVE THE SPECTRUM EFFICIENCY OF THE MICROWAVE SYSTEMS, USING M-ARY DIGITAL SCHEMES SUCH AS M-ARY QAM [1.4]. IN FACT M- ARYQAM SCHEMES PRESENT MUCH BETTER POWER/BANDWIDT EFFICIENCY THAN THE EQUIVALENT M-ARY PSK IN AWGN ENVIRONMENT. MOREOVER, COCHANNEL …
-
Digital Transmission by Hermite N-Dimensional Antipodal Scheme
… amplitude or frequency modulation. The bandwidth efficiency of the amplitude Hermite method is found to be as good as filtered BPSK in practice, while the bit error rates for both modulations are identical. Hermite Keying (HK), the FM modulation version of the N-dimensional Hermite transmission, …
-
Performance Analysis and Modelling of Spectrum Handoff Schemes in Cognitive Radio Networks. Modelling and Analysis of Spectrum Handoff Decision Schemes in Cognitive Radio Networks using the Queuing Theory and Simulation for Licensed and Unlicensed Spectrum Bands.
… controlled by the available radio frequency spectrum, government regulatory agencies have recently adopted a strict approach to the licensing of limited amounts of spectrum to different entities (e.g., public safety, military, service providers, unlicensed devices, and TV). All of them …
-
Efficient spectrum sensing and utilization for cognitive radio
… been introduced to opportunistically exploit the spectrum. We present a robust and cost-effective design to ensure the improvement of spectrum efficiency with CR. We first propose probability-based spectrum sensing by utilizing the statistical characteristics of licensed channel occupancy, which …
-
Cooperative relaying using USRP and GNU radio
… interference, low signal strength, reduced spectrum efficiency etc. which makes this system less reliable. Because of this reason, researchers are continuously working to develop technologies that can make the performance of a wireless system much better. Cooperative Communications is one of …
-
Analysis, design and implementation of front-end reconfigurable antenna systems (FERAS)
… requirements. Such applications increase spectrum efficiency as well as the power utilization in modern wireless systems. The emphasis of this dissertation revolves around the following question: Is it possible to come up with new techniques to achieve reconfigurable antenna systems with …
-
Performance analysis of FBMC over OFDM in Cognitive Radio Network
… User (SU) to fully utilize the available spectrum resource by sensing the existence of spectrum holes without causing interference to the Primary User (PU). However, PU detection has been one of the main challenges in CR technology. In comparison to traditional wireless communication …
-
Deep Recurrent Q Networks for Dynamic Spectrum Access in Dynamic Heterogeneous Envirnments with Partial Observations
Dynamic Spectrum Access (DSA) has strong potential to address the need for improved spectrum efficiency. Unfortunately, traditional DSA approaches such as simple "sense-and-avoid" fail to provide sufficient performance in many scenarios. Thus, the combination of sensing with deep reinforcement …
-
Resource management of cognitive radio networks with optimization methods.
… future for wireless communications with higher spectrum efficiency. A cognitive radio transceiver senses its environment and dynamically adapts its transmission methods and the channel usage so that the induced interference to the licensed user is regulated. The dissertation focuses on solving …
-
Power Control and Resource Allocation for QoS-Constrained Wireless Networks
… reliable transmissions and limited wireless spectrum resources. Although multiple-input multiple-output (MIMO) systems have shown the ability to provide reliable transmissions in fading channels, it is not practical for single-antenna devices to support MIMO system due to cost and hardware …
-
A Business Framework for Dynamic Spectrum Access in Cognitive Networks
… for cognitive networks and provide dynamic spectrum access for better spectrum efficiency. We are interested in assessing the practical impact of Cognitive Networks on the Wireless Communication industry. Our goal is to propose a formal business model that will help assess the implications …
-
Some Modeling and Optimization Problems in Cognitive Radio Ad Hoc Networks
… which was once done in hardware. Due to its spectrum sensing, learning, and adaptation capabilities, CR is able to address the heart of the problem associated with spectrum scarcity (via dynamic spectrum access (DSA)) and interoperability (via channel switching). It is envisioned that CR will …
-
Energy and Spectral Efficient Wireless Communications
<p>Energy and spectrum are two precious commodities for wireless communications. How to improve the energy and spectrum efficiency has become two critical issues for the designs of wireless communication systems. This dissertation is devoted to the development of energy and spectral efficient …
Page 1 of 2