Tesis doctoral de Mario García Lozano
The deployment of 3g/3.5g cellular networks challenges traditional radio planning and optimization strategies. Unlike fdma based 2g systems, coverage and capacity are tightly coupled and must be treated as a whole. Besides new and more sophisticated radio resource management (rrm) algorithms are present along with a more flexible network with many interdependent parameters, whose joint adjustment is not trivial. A new radio planning paradigm appears in which the radio network is optimized by means of complex algorithms both in a static and a dynamic way. this ph.D. Thesis provides a contribution to the radio network optimization of 3g/3.5g networks. several issues to improve radio network planning have been investigated and new methods, guidelines and strategies of analysis have been proposed with the final objective of enhancing the wireless access network performance. Dynamic mechanisms being in the blurred line between radio planning and rrm are also devised and studied. the first part of this dissertation deals with the configuration of base stations (bss) the impact of pilot powers, downtilt of antennas and interactions thereof with soft handover parameters are investigated. Effects beyond well-known facts are outlined and new planning guidelines are derived. given the results, an automatic planning strategy is devised to automate the configuration of these parameters and to find a combination such as traffic is effectively equalized among cells and a higher capacity is achieved. The technique is based on the simulated annealing metaheuristic and is able to improve the global performance of the network, represented by a cost function containing information on the load factor and subject to other quality constraints. The importance of uplink (ul) requirements, usually missed by existent proposals, has been also included and analytically addressed. reconfiguring bss is not the only means to modify cell shapes, in this sense the study is extended by introducing repeaters, which allow generating distributed coverage areas. This is the context of the second part of the thesis. New effects not present in fdma based 2g systems imply that the radio planning process becomes more complex. Most existent papers dealing with repeaters in wcdma networks, ignore these effects or claim their irrelevance. That is why the research work was focused in modeling them, quantifying their impact and deriving radio planning guidelines to enhance the final performance of the radio access network. The new expression for the feasibility condition has been analytically obtained showing a tradeoff between capacity and coverage. This has been analyzed both theoretically and by means of simulations and the adjustment of several parameters which have a significant impact is discussed to derive practical rules of thumb. Variation on the coverage of the donor cell before and after installing repeaters is also modeled. subsequently, it is proposed a new methodology to analyze wcdma networks with repeaters deployment, considering realistically path delays and the behavior of rake receivers. This allows an enhanced analysis with respect to traditional approaches which, under certain circumstances, tend to provide erroneously optimistic metrics. the final part of the dissertation goes one step further in automatic planning and two dynamic mechanisms are proposed and validated so that the network can react and self tune in front of changes in traffic conditions. The first one follows some previous conclusions and aims at detecting if one of the links has capacity problems and if so, favors it to delay congestion control actions. finally, hsdpa technology is introduced and, after analyzing the resources to be shared with a previous release of umts, it is concluded that a system that dynamically manages the ovsf code tree is desired. A mechanism aiming at maximizing cell throughput while guaranteeing blocking and dropping criteria is proposed and validated.
Datos académicos de la tesis doctoral «Contribution to wireless access optimization and dynamic enhancement of wcdma networks«
- Título de la tesis: Contribution to wireless access optimization and dynamic enhancement of wcdma networks
- Autor: Mario García Lozano
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 12/01/2009
Dirección y tribunal
- Director de la tesis
- Silvia Ruiz Boque
- Tribunal
- Presidente del tribunal: ramon Agusti comes
- Luis m. Correia (vocal)
- narciso Cardona marcet (vocal)
- leandro Juan llácer (vocal)