Zakrzewska, Anna

Nuværende og fremtidige mobilnet vil bestå af multiple, sameksisterende Radio Access Teknologiers (RAT), forskellige cellestørrelser (makro-, metro-, pico- og femtoceller) udgørende et heterogent net (HetNet), samt forskellige basestationsarkitekturer. Denne afhandling behandler forskellige aspekter af mobilnet med fokus på de vigtigste udfordringer skabt af denne heterogenitet.Til effektivt at styre denne diversitet, foreslås her en nyskabende hierarkisk metode, der tager alle ressourcer, spektrale, optiske og processorkraft, i betragtning. Dette generiske framework dækker alle former for netværksheterogenitet og kan være gavnlig i alle faser af netværksudrulning og drift. Ydermere er et dedikeret studie af RAT-selektion og ressourceallokering blevet udført og en ny optimeringsmodel introduceres og evalueres. Resultaterne viser en signikant reduktion i antallet af handovers på bekostning af et mindre fald i throughput, hvilket fører til mere stabile forbindelser i multi-RAT miljøer.En ny HetNet-arkitektur med adskilt control- og user-plane bliver undersøgt grundigt. Studier her fokuserer på problemet med krav til og tildeling af soft-pilot, og der foreslås en optimeringsmodel samt et antal heuristikker. En analyse af en række udrulningsscenarier demonstrerer anvendeligheden af denne arkitektur. Ydermere viser resultaterne de potentielle fordele ved denne arkitektur med hensyn til mobility management og energieektivitet.Netværksdeling er efterhånden blevet en udbredt strategi for operatører og det er vigtigt at få undersøgt fordelene ved sådan et samarbejde. Her foretages en teletrakteoretisk analyse af forskellige tilgange til netværksdimensionering, hvilket udmunder i konkrete anbefalinger. Alle de præsenterede koncepter er standard-uafhængige, hvilket vil sige, at de kan anvendes på enhver RAT inklusive teknologier, der har potentialet til at blive brugt i næste generations mobilnet. Dette gør de foreslåede løsninger universelle og i tråd med aktuelle tendenser i design af fremtidens mobilnet.Current and future mobile networks will constitute of multiple coexisting Radio Access Technologies (RATs), cells of different size (macro-, metro-, pico-, femtocells) forming a Heterogeneous Network (HetNet), and Base Stations (BSs) of various architectures. This thesis addresses different aspects of mobile networks and focuses on the main challenges resulting from their heterogeneity.To effectively manage this diversity, a novel hierarchical approach considering all types of resources, spectral, optical and computational is proposed. The generic framework covers all kinds of network heterogeneity and can be beneficial at any stage of network deployment or operation. Furthermore, a dedicated study of RAT selection and resource allocation is performed and a new optimisation model is introduced and evaluated. The results show a significant reduction of number of handovers at the cost of a slight throughput degradation, which leads to a more stable connectivity in multi-RAT environments.A new HetNet architecture with control and user plane separation is thoroughly evaluated. The study focuses on the soft-pilot requirements and assignment problem, which is solved using a proposed optimisation model and a number of heuristic approaches. The analysis for a number of deployment scenarios demonstrates the feasibility of this architecture. Furthermore, the obtained results show the potential benefits of the new architecture in terms of mobility management and energy efficiency. Network sharing has become a common strategy among network operators and it is important to evaluate the benefits of such cooperation. A teletrac theory analysis for various network dimensioning approaches is provided and based on the results clear recommendations are given.All the presented concepts are standard agnostic, meaning that they can be applied to any RAT, including technologies that have the potential to become part of the next generation mobile networking. This makes the proposed solutions universal and in line with the current trends to design future mobile networks

Online Research Database In Technology

4G and Beyond - Exploiting Heterogeneity in Mobile Networks

http://orbit.dtu.dk/ws/files/91775214/AnnaZakrzewska_PhDthesis20140406.pdf

4G and Beyond - Exploiting Heterogeneity in Mobile Networks

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Online Research Database In Technology