202 research outputs found
EVEREST IST - 2002 - 00185 : D23 : final report
Deliverable pĂșblic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version
Soft handover issues in radio resource management for 3G WCDMA networks
PhDMobile terminals allow users to access services while on the move. This unique
feature has driven the rapid growth in the mobile network industry, changing it from a
new technology into a massive industry within less than two decades.
Handover is the essential functionality for dealing with the mobility of the mobile
users. Compared with the conventional hard handover employed in the GSM mobile
networks, the soft handover used in IS-95 and being proposed for 3G has better
performance on both link and system level.
Previous work on soft handover has led to several algorithms being proposed and
extensive research has been conducted on the performance analysis and parameters
optimisation of these algorithms. Most of the previous analysis focused on the uplink
direction. However, in future mobile networks, the downlink is more likely to be the
bottleneck of the system capacity because of the asymmetric nature of new services,
such as Internet traffic.
In this thesis, an in-depth study of the soft handover effects on the downlink
direction of WCDMA networks is carried out, leading to a new method of optimising
soft handover for maximising the downlink capacity and a new power control
approach
Final report on the evaluation of RRM/CRRM algorithms
Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin
Radio network planning and optimisation for WCDMA
The present thesis introduces the radio network planning process and optimisation for WCDMA (FDD mode), as defined by 3GPP. This thesis consists of three parts: modelling and tools for radio network planning, process for pre-operational network control and optimisation for the operational network. General challenges to face in 3G network control are based on the fact that many issues are interconnected and should be simultaneously considered, such as
Planning means not only to meet current status and demands, but the solution should also comply with the future requirements by providing an acceptable development path. Traffic modelling is not only the question about the total amount of traffic growth, but also the question about the future service distribution and performance demands. All CDMA systems have a relation between capacity and coverage. Consequently, the network planning itself is not only based on propagation estimation but also on the interference situation in the network. Ideally, site selection consideration will be done based on the network analysis with planned load and traffic/service portfolio, taking possible co-siting constraints into account. Provision of multiple services and seamless management of at least two multiple access systems require rapid evolution of the management tools and processes. The network performance in terms of capacity, quality, and implementation and operational costs forms a multidimensional space. Operators' task will be to convert the business strategy to an operating point in the performance space in a cost efficient manner.
The contribution of this thesis in terms of modelling and tools is as follows:
Improvement of the accuracy of radio link budget by introducing power control headroom (also called fast fading margin). Improvement of loading equation by introducing a transmit power increase term. Development of theory and modelling for a planning tool capable of multi-service and multi-carrier interference, capacity and coverage analysis. Development and implementation an interface taking into account the true traffic distribution (not uniform) and terminal speed.
In the area of pre-operational planning process the contribution of this thesis is as follows:
Development of dimensioning methodology for multi-service network site density estimation, utilising the modelling of power control headroom, transmit power increase, soft handover and Eb/N0. Development of radio network planning process for multi-service environment including capacity and coverage evaluation for a given traffic mixture, quality and area requirements. Analysis of means to improve radio network performance with Mast Head Amplifier (MHA), diversity reception, sectorisation and proper antenna selection.
In the area of optimisation of the operational network the contribution of this thesis is as follows:
Definition for optimisation target in the case of 3G. The optimisation will be capacity-quality trade-off management instead of plain quality improvement process. Introduction of Self Organizing Map (SOM) in the analysis of cellular networks. Analysis of the applicability of SOM in WCDMA cellular network optimisation. Introduction of SOM based applications to support network capacity-quality trade-off management.
It is worth noting that process and methods described in this work are not limited to 3G systems with WCDMA radio access technology, but they are applicable to other CDMA standards as well.reviewe
Contribution to resource management in cellular access networks with limited backhaul capacity
La interfaz radio de los sistemas de comunicaciones mĂłviles es normalmente considerada como
la Ășnica limitaciĂłn de capacidad en la red de acceso radio. Sin embargo, a medida que se van
desplegando nuevas y mĂĄs eficientes interfaces radio, y de que el trĂĄfico de datos y multimedia va
en aumento, existe la creciente preocupaciĂłn de que la infraestructura de transporte (backhaul) de
la red celular pueda convertirse en el cuello de botella en algunos escenarios. En este contexto, la
tesis se centra en el desarrollo de técnicas de gestión de recursos que consideran de manera
conjunta la gestiĂłn de recursos en la interfaz radio y el backhaul. Esto conduce a un nuevo
paradigma donde los recursos del backhaul se consideran no sĂłlo en la etapa de dimensionamiento,
sino que ademĂĄs son incluidos en la problemĂĄtica de gestiĂłn de recursos.
Sobre esta base, el primer objetivo de la tesis consiste en evaluar los requerimientos de
capacidad en las redes de acceso radio que usan IP como tecnologĂa de transporte, de acuerdo a las
recientes tendencias de la arquitectura de red. En particular, se analiza el impacto que tiene una
soluciĂłn de transporte basada en IP sobre la capacidad de transporte necesaria para satisfacer los
requisitos de calidad de servicio en la red de acceso. La evaluaciĂłn se realiza en el contexto de la
red de acceso radio de UMTS, donde se proporciona una caracterizaciĂłn detallada de la interfaz
Iub. El anĂĄlisis de requerimientos de capacidad se lleva a cabo para dos diferentes escenarios:
canales dedicados y canales de alta velocidad. Posteriormente, con el objetivo de aprovechar
totalmente los recursos disponibles en el acceso radio y el backhaul, esta tesis propone un marco de
gestión conjunta de recursos donde la idea principal consiste en incorporar las métricas de la red de
transporte dentro del problema de gestiĂłn de recursos. A fin de evaluar los beneficios del marco de
gestiĂłn de recursos propuesto, esta tesis se centra en la evaluaciĂłn del problema de asignaciĂłn de
base, como estrategia para distribuir el trĂĄfico entre las estaciones base en funciĂłn de los niveles de
carga tanto en la interfaz radio como en el backhaul. Este problema se analiza inicialmente
considerando una red de acceso radio genĂ©rica, mediante la definiciĂłn de un modelo analĂtico
basado en cadenas de Markov. Dicho modelo permite calcular la ganancia de capacidad que puede
alcanzar la estrategia de asignaciĂłn de base propuesta. Posteriormente, el anĂĄlisis de la estrategia
propuesta se extiende considerando tecnologĂas especĂficas de acceso radio. En particular, en el
contexto de redes WCDMA se desarrolla un algoritmo de asignaciĂłn de base basado en simulatedannealing
cuyo objetivo es maximizar una funciĂłn de utilidad que refleja el grado de satisfacciĂłn
de las asignaciones respecto los recursos radio y transporte. Finalmente, esta tesis aborda el diseño
y evaluaciĂłn de un algoritmo de asignaciĂłn de base para los futuros sistemas de banda ancha
basados en OFDMA. En este caso, el problema de asignaciĂłn de base se modela como un problema
de optimizaciĂłn mediante el uso de un marco de funciones de utilidad y funciones de coste de
recursos. El problema planteado, que considera que existen restricciones de recursos tanto en la
interfaz radio como en el backhaul, es mapeado a un problema de optimizaciĂłn conocido como
Multiple-Choice Multidimensional Knapsack Problem (MMKP). Posteriormente, se desarrolla un
algoritmo de asignaciĂłn de base heurĂstico, el cual es evaluado y comparado con esquemas de
asignaciĂłn basados exclusivamente en criterios radio. El algoritmo concebido se basa en el uso de
los multiplicadores de Lagrange y estå diseñado para aprovechar de manera simultånea el balanceo
de carga en la intefaz radio y el backhaul.Postprint (published version
Laajakaistaisen CDMA solukkoverkon kapasiteetti makrosoluympÀristössÀ
TÀmÀn diplomityön tarkoitus on tutkia kuormitetun laajakaistaiseen koodijakomenetelmÀÀn perustuvan makrosoluverkon kapasiteettia.
Työn tavoitteena on selvittÀÀ simulointien avulla, miten solukkoverkon palvelemien matkaviestinten kÀyttÀjien eri tiedonsiirtonopeudet ja liikkumisnopeudet vaikuttavat jÀrjestelmÀn kokonaiskapasiteettiin.
TehonsÀÀdön ja samalla taajuudella olevien solujen vÀlisen kanavananvaihdon toiminnallisuuksien ja parametrien vaikutuksia tutkitaan verkon kapasiteetin kannalta Tutkimus alkaa hajaspektriteknologian perusteiden ja UMTS:n (Universal Mobile Telecommunications System) FDD (Frequency Division Duplex) osan esittelyillÀ.
Laajakaistaisen koodijakoon perustuvan verkon kapasiteetin ominaisuudet esitellÀÀn.
MakrosoluympÀristö mÀÀritellÀÀn ja sen perusominaisuudet esitellÀÀn.
Laajakaistaista koodijakoon perustuvaa UMTS-jÀrjestelmÀÀ mallintava simulointiohjelmisto kuvaillaan ennen tÀmÀn diplomityön simulointien ja tulosten esittelyÀ ja analysointia.
TÀmÀn tutkimuksen simuloinnit suoritetaan yksinkertaisessa esikaupunkityyppisessÀ makrosoluympÀristössÀ.
Laajakaistaisen koodijakoon perustuvan jÀrjestelmÀn kapasiteetti kÀyttÀytyy hyvin dynaamisesti.
Kapasiteetti riippuu kÀyttÀjien jakaumasta verkossa, tiedonsiirtonopeuksista, liikkumisnopeudesta, hÀiriön mÀÀrÀstÀ ja tehonsÀÀdön ja samalla taajuudella olevien solujen kanavanvaihdon parametrien valinnasta.
PuhekÀyttÀjien lisÀys vaikuttaa enemmÀn suuria tiedonsiirtonopeuksia kuin alhaisia tiedonsiirtonopeuksia kÀyttÀvien tilaajien palvelun laatuun.
Solujen vÀliset hÀiriöt vaikuttavat merkittÀvÀsti verkon kapasiteettiin.
Alhaiset tehonsÀÀdön virheet eivÀt vaikuta merkittÀvÀsti hitaasti liikkuvien kÀyttÀjien saamaan palvelun laatuun.
Samalla taajuudella olevien solujen kanavanvaihdon kynnysarvo tulisi optimoida, jotta voitaisiin saavuttaa verkon suurin mahdollinen kapasiteetti ja minimoida hÀiriöt
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