Genetic Algorithm Aided Antenna Placement in 3D and Parameter Determination Considering Electromagnetic Field Pollution Constraints

This paper presents genetic algorithm based method for antenna placement in 3D space and parameter determination satisfying environmental electromagnetic field pollution constraints. The main goal is to find out antenna parameters (power, position in 3D, azimuth and elevation) in the area of interest so that electromagnetic field satisfies minimal electromagnetic field strength for service availability and, at the same time, be below prescribed limit in restricted subareas (people populated areas). The proposed method is validated with two real world antenna types and with seven different terrain configurations (various restricted areas). Besides finding the most optimal antenna parameters, the method finds “almost” optimal solutions which give certain freedom to choose alternative antenna position if optimal is not available. The investigation described here is extension of previous 2D research

Self-organisation in LTE networks : an investigation

Mobile telecommunications networks based on Long Term Evolution (LTE) technology promise faster throughput to their users. LTE networks are however susceptible to a phenomenon known as inter-cell interference which can greatly reduce the throughput of the network causing unacceptable degradation of performance for cell edge users. A number of approaches to mitigating or minimising inter-cell interference have been presented in the literature such as randomisation, cancellation and coordination. The possibility of coordination between network nodes in an LTE network is made possible through the introduction of the X2 network link. This thesis explores approaches to reducing the effect of inter-cell interference on the throughput of LTE networks by using the X2 link to coordinate the scheduling of radio resources. Three approaches to the reduction of inter-cell interference were developed. Localised organisation is a centralised scheme in which a scheduler is optimised by a Genetic Algorithm (GA) to reduce interference. Networked organisation makes use of the X2 communications link to enable the network nodes to exchange scheduling information in a way that lowers the level of interference across the whole network. Finally a more distributed and de-centralised approach is taken in which each of the network nodes optimises its own scheduling in coordination with its neighbours. An LTE network simulator was built to allow for experimental comparison between these techniques and a number of existing approaches and to serve as a test bed for future algorithm development. These approaches were found to significantly improve the throughput of the cell edge users who were most affected by intereference. In particular the networked aspect of these approaches yielded the best initial results showing clear improvement over the existing state of the art. The distributed approach shows significant promise given further development.EPSR

Self-organisation in LTE networks : an investigation

Mobile telecommunications networks based on Long Term Evolution (LTE) technology promise faster throughput to their users. LTE networks are however susceptible to a phenomenon known as inter-cell interference which can greatly reduce the throughput of the network causing unacceptable degradation of performance for cell edge users. A number of approaches to mitigating or minimising inter-cell interference have been presented in the literature such as randomisation, cancellation and coordination. The possibility of coordination between network nodes in an LTE network is made possible through the introduction of the X2 network link. This thesis explores approaches to reducing the effect of inter-cell interference on the throughput of LTE networks by using the X2 link to coordinate the scheduling of radio resources. Three approaches to the reduction of inter-cell interference were developed. Localised organisation is a centralised scheme in which a scheduler is optimised by a Genetic Algorithm (GA) to reduce interference. Networked organisation makes use of the X2 communications link to enable the network nodes to exchange scheduling information in a way that lowers the level of interference across the whole network. Finally a more distributed and de-centralised approach is taken in which each of the network nodes optimises its own scheduling in coordination with its neighbours. An LTE network simulator was built to allow for experimental comparison between these techniques and a number of existing approaches and to serve as a test bed for future algorithm development. These approaches were found to significantly improve the throughput of the cell edge users who were most affected by intereference. In particular the networked aspect of these approaches yielded the best initial results showing clear improvement over the existing state of the art. The distributed approach shows significant promise given further development.EPSR

Benchmarking a wide spectrum of metaheuristic techniques for the radio network design problem

The radio network design (RND) is an NP-hard optimization problem which consists of the maximization of the coverage of a given area while minimizing the base station deployment. Solving RND problems efficiently is relevant to many fields of application and has a direct impact in the engineering, telecommunication, scientific, and industrial areas. Numerous works can be found in the literature dealing with the RND problem, although they all suffer from the same shortfall: a noncomparable efficiency. Therefore, the aim of this paper is twofold: first, to offer a reliable RND comparison base reference in order to cover a wide algorithmic spectrum, and, second, to offer a comprehensible insight into accurate comparisons of efficiency, reliability, and swiftness of the different techniques applied to solve the RND problem. In order to achieve the first aim we propose a canonical RND problem formulation driven by two main directives: technology independence and a normalized comparison criterion. Following this, we have included an exhaustive behavior comparison between 14 different techniques. Finally, this paper indicates algorithmic trends and different patterns that can be observed through this analysis.Publicad

Design of Radio-Frequency Arrays for Ultra-High Field MRI

Magnetic Resonance Imaging (MRI) is an indispensable, non-invasive diagnostic tool for the assessment of disease and function. As an investigational device, MRI has found routine use in both basic science research and medicine for both human and non-human subjects. Due to the potential increase in spatial resolution, signal-to-noise ratio (SNR), and the ability to exploit novel tissue contrasts, the main magnetic field strength of human MRI scanners has steadily increased since inception. Beginning in the early 1980’s, 0.15 T human MRI scanners have steadily risen in main magnetic field strength with ultra-high field (UHF) 8 T MRI systems deemed to be insignificant risk by the FDA (as of 2016). However, at UHF the electromagnetic fields describing the collective behaviour of spin dynamics in human tissue assume ‘wave-like’ behaviour due to an increase in the processional frequency of nuclei at UHF. At these frequencies, the electromagnetic interactions transition from purely near-field interactions to a mixture of near- and far-field mechanisms. Due to this, the transmission field at UHF can produce areas of localized power deposition – leading to tissue heating – as well as tissue-independent contrast in the reconstructed images. Correcting for these difficulties is typically achieved via multi-channel radio-frequency (RF) arrays. This technology allows multiple transmitting elements to synthesize a more uniform field that can selectively minimize areas of local power deposition and remove transmission field weighting from the final reconstructed image. This thesis provides several advancements in the design and construction of these arrays. First, in Chapter 2 a general framework for modeling the electromagnetic interactions occurring inside an RF array is adopted from multiply-coupled waveguide filters and applied to a subset of decoupling problems encountered when constructing RF arrays. It is demonstrated that using classic filter synthesis, RF arrays of arbitrary size and geometry can be decoupled via coupling matrix synthesis. Secondly, in Chapters 3 and 4 this framework is extended for designing distributed filters for simple decoupling of RF arrays and removing the iterative tuning portion of utilizing decoupling circuits when constructing RF arrays. Lastly, in Chapter 5 the coupling matrix synthesis framework is applied to the construction of a conformal transmit/receive RF array that is shape optimized to minimize power deposition in the human head during any routine MRI examination

Multicore Parallelization of CHC for Optimal Aerogenerator Placement in Wind Farms

In this paper, we study a parallelization of CHC algorithm (Crossover elitism population, Half uniform crossover combination, Cataclysm mutation) to solve the problem of placement of wind turbines in a wind farm. We also analyze the solutions obtained when we use both, the sequential and parallel version for the CHC algorithm. In this case we study the behavior of parallel metaheuristics using an island model to distribute the algorithm in different cores and compare this proposal with the sequential version to analyse the number of evaluation to find the best configuration, output power extracted, plant coefficient, evaluations needed, memory consumption, and execution time for different number of core and different problem sizes.XX Workshop Agentes y Sistemas Inteligentes.Red de Universidades con Carreras en Informátic

Multicore Parallelization of CHC for Optimal Aerogenerator Placement in Wind Farms

In this paper, we study a parallelization of CHC algorithm (Crossover elitism population, Half uniform crossover combination, Cataclysm mutation) to solve the problem of placement of wind turbines in a wind farm. We also analyze the solutions obtained when we use both, the sequential and parallel version for the CHC algorithm. In this case we study the behavior of parallel metaheuristics using an island model to distribute the algorithm in different cores and compare this proposal with the sequential version to analyse the number of evaluation to find the best configuration, output power extracted, plant coefficient, evaluations needed, memory consumption, and execution time for different number of core and different problem sizes.XX Workshop Agentes y Sistemas Inteligentes.Red de Universidades con Carreras en Informátic

Multicore Parallelization of CHC for Optimal Aerogenerator Placement in Wind Farms

In this paper, we study a parallelization of CHC algorithm (Crossover elitism population, Half uniform crossover combination, Cataclysm mutation) to solve the problem of placement of wind turbines in a wind farm. We also analyze the solutions obtained when we use both, the sequential and parallel version for the CHC algorithm. In this case we study the behavior of parallel metaheuristics using an island model to distribute the algorithm in different cores and compare this proposal with the sequential version to analyse the number of evaluation to find the best configuration, output power extracted, plant coefficient, evaluations needed, memory consumption, and execution time for different number of core and different problem sizes.XX Workshop Agentes y Sistemas Inteligentes.Red de Universidades con Carreras en Informátic

Optimising BFWA networks

EThOS - Electronic Theses Online ServiceGBUnited Kingdo