RAT selection algorithims for common radio resource management

University of Technology, Sydney. Faculty of Engineering and Information Technology.The future wireless network is expected to be a heterogeneous network, which integrates different Radio Access Technologies (RATs) through a common platform. A major challenge arising from the heterogeneous network is Radio Resource Management (RRM) strategy. Common RRM (CRRM) has been proposed in the literature to jointly manage radio resources among a number of overlapped RATs in an optimized way. RAT selection algorithm is one of the key research areas in CRRM. In the literature, a number of RAT selection algorithms have been proposed and some performance evaluations have been conducted. However, this area still has many challenges. Some performance metrics still have not been evaluated well and the existing algorithms can be further improved. In this thesis, some performance evaluations on a number of RAT selection algorithms have been carried out. The effects of load threshold setting on Load Balancing (LB) based RAT selection algorithm’s performance are evaluated. It is found that setting a proper load threshold can achieve a more balanced load distribution among overlapped cells. However, it will also cause higher Direct Retry (DR)/Vertical Handover (VHO) probability and in turn higher overhead and blocking/dropping probability. This thesis evaluates the performance of three RAT selection algorithms, LB based using maximum resource consumption, LB based using minimum resource consumption, and service based algorithms, in terms of traffic distribution, blocking probability, throughput, and throughput fairness for a co-located GERAN/UTRAN/WLAN network. Simulation results show that in terms of blocking probability, the service based algorithm is the worst one when the traffic load is high. In terms of data throughput, the LB based using maximum resource consumption algorithm performs better than the other two when the traffic load is low. However, the service based algorithm outperforms the other two when the traffic load is high. In terms of throughput fairness, the service based algorithm achieves the best performance. The relationship among overall downlink data throughput, user satisfaction rate, and path loss threshold is studied in this thesis. It is found that in some cases, an optimum path loss threshold value can be found to achieve better performance in terms of both overall throughput and user satisfaction rate. However, in other cases, a tradeoff has to be made between them. This thesis studies policy based RAT selection algorithms for a co-located UMTS/GSM network. A three-complex policy based algorithm called IN*VG*Load algorithm is proposed based on improvements on the existing IN*VG algorithm. The simulation results show that the IN*VG*Load algorithm can optimize the system performance in highly loaded co-located UMTS/GSM networks. A Proposed Policy Based Algorithm 2 is found to be suitable for low to medium loaded UMTS/GSM networks. In order to support the conceptual development of RAT selection algorithms in heterogeneous networks, the theory of Markov model is used. This thesis proposes both user level and network level Markov models for a co-located GERAN/UTRAN/ WLAN network. The proposed Markov models are not only extensions of the existing two co-located RATs models but more complex with more state transitions. The performance of two basic RAT selection algorithms: LB based and service based algorithms are evaluated in terms of call blocking probability. The numerical results obtained from the proposed network level Markov model are validated by simulation results

Common Radio Resource Management Strategies for Quality of Service Support in Heterogeneous Wireless Networks

Hoy en día existen varias tecnologías que coexisten en una misma zona formando un sistema heterogéneo. Además, este hecho se espera que se vuelva más acentuado con todas las nuevas tecnologías que se están estandarizando actualmente. Hasta ahora, generalmente son los usuarios los que eligen la tecnología a la que se van a conectar, ya sea configurando sus terminales o usando terminales distintos. Sin embargo, esta solución es incapaz de aprovechar al máximo todos los recursos. Para ello es necesario un nuevo conjunto de estrategias. Estas estrategias deben gestionar los recursos radioeléctricos conjuntamente y asegurar la satisfacción de la calidad de servicio de los usuarios. Siguiendo esta idea, esta Tesis propone dos nuevos algoritmos. El primero es un algoritmo de asignación dinámica de recusos conjunto (JDRA) capaz de asignar recursos a usuarios y de distribuir usuarios entre tecnologías al mismo tiempo. El algoritmo está formulado en términos de un problema de optimización multi-objetivo que se resuelve usando redes neuronales de Hopfield (HNNs). Las HNNs son interesantes ya que se supone que pueden alcanzar soluciones sub-óptimas en cortos periodos de tiempo. Sin embargo, implementaciones reales de las HNNs en ordenadores pierden esta rápida respuesta. Por ello, en esta Tesis se analizan las causas y se estudian posibles mejoras. El segundo algoritmo es un algoritmo de control de admisión conjunto (JCAC) que admite y rechaza usuarios teniendo en cuenta todas las tecnologías al mismo tiempo. La principal diferencia con otros algorimos propuestos es que éstos últimos toman las dicisiones de admisión en cada tecnología por separado. Por ello, se necesita de algún mecanismo para seleccionar la tecnología a la que los usuarios se van a conectar. Por el contrario, la técnica propuesta en esta Tesis es capaz de tomar decisiones en todo el sistema heterogéneo. Por lo tanto, los usuarios no se enlazan con ninguna tecnología antes de ser admitidos.Calabuig Soler, D. (2010). Common Radio Resource Management Strategies for Quality of Service Support in Heterogeneous Wireless Networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/7348Palanci

Common Radio Resource Management Policy for Multimedia Traffic in Beyond 3G Heterogeneous Wireless Systems

Beyond 3G wireless systems will be composed of a variety of Radio Access Technologies (RATs) with different, but also complementary, performance and technical characteristics. To exploit such diversity while guaranteeing the interoperability and efficient management of the different RATs, common radio resource management (CRRM) techniques need to be defined. This work proposes and evaluates a CRRM policy that simultaneously assigns to each user an adequate combination of RAT and number of radio resources within such RAT to guarantee its QoS requirements. The proposed CRRM technique is based on linear objective functions and programming tools

A 4-Dimensional Markov model for the evaluation of radio access technology selection strategies in multiservice scenarios

In order to support the conceptual development of Common Radio Resource Management (CRRM) algorithms, this paper provides an analytical approach to the performance evaluation of Radio Access Technology (RAT) selection procedures in a multi-RAT/multiservice environment. In particular, a 4-Dimensional (4D) Markovian model is devised so as to consider the allocation of voice and data services in a GERAN/UTRAN system. Through the analytical definition of well-established Key Performance Indicators (KPIs) we provide numerical results on the evaluation of a load balancing RAT allocation policy.Peer ReviewedPostprint (published version

On the optimum traffic allocation in heterogeneous CDMA/TDMA networks

This paper presents the optimum user allocation in heterogeneous scenarios with CDMA and TDMA technologies in order to minimize the total outage probability in the uplink. An analytical model reflecting the different nature of the two access technologies is presented in order to formulate the optimization procedure. It is shown how the optimum allocation depends on the specific parameters of the two technologies, as illustrated with some representative results. The proposed optimization methodology is claimed to have applicability in the field of Common Radio Resource Management strategies for Beyond 3G networks.Peer Reviewe

Common Radio Resource Management: Joint Call Admission Control And Traffic Offloading Method

The concept of Common Radio Resource Management (CRRM) has been proposed by 3GPP in order to efficiently manage the common pool of radio resources that are available for each of the existing radio access technologies in the heterogeneous wireless networks (HWNs). The main challenge of CRRM for HWNs is to search the best connection for the demanded services, enabling calls transference from one interface to another seamlessly and utilizing the availability of all radio resources. Thus, this thesis proposes a joint call admission control (JCAC) and traffic offloading algorithms in the CRRM for an integrated cellular and mobile network. The contributions of this work are threefold. First, a user mobility model in the wireless overlay network is proposed

A Modelling Framework for Common Radio Resource Management in Mobile Communication Systems

Im Rahmen dieser Arbeit wurde ein Modellierungsframework für die Untersuchung der technologieübergreifenden Verwaltung von Ressourcen heterogener Funkzugangsnetze (Common Radio Resource Management – CRRM) entwickelt. Die fünf Komponenten Umwelt (ENV), Nutzerendgerät (UE), Funkzugangssystem (RAS), CRRM-Informationsmanager (CRRM-IM) und CRRM-Entscheider (CRRM-D) können für die Gestaltung von zentralen bis dezentralen CRRM-Architekturen kombiniert werden. Sie decken damit ein weites Spektrum an möglichen CRRM-Einsatzszenarien ab. Dabei ermöglicht eine klare Struktur des zugrunde liegenden Modells die einfache Übertragung von Lösungsmethoden aus dem Gebiet der Multikriterienoptimierung. Ein integriertes Kostenmodell ermöglicht eine Kosten-/ Nutzen-Analyse für CRRM-Algorithmen und Architekturen. Die Verwendung eines hybriden Simulationsmodells ermöglicht die einfache Integration analytischer Funkzugangstechnologiemodelle und die Simulation komplexer Szenarien mit geringem Zeit- und Speicherbedarf. Hierbei liefern simulative Teilmodelle zeitgetreu neue Eingabeparameter für analytische Teilmodelle, deren Ausgabeparameter wiederum die Eingabeparameter der simulativen Teilmodelle sind. Nach diesem Modell wurde der auf OMNeT++ basierende diskrete ereignisorientierte Simulator HEKATE entwickelt. Der Simulator erwies sich als geeignet die zeiteffiziente Untersuchung von CRRM-Szenarien für UMTS- und GSM/EGPRS-Funkzugangssysteme durchzuführen.This work presents a modeling framework for the efficient evaluation of Common Radio Resource Management (CRRM). Centralized as well as decentralized scenarios can be clearly defined by five standard components, namely the radio access system (RAS), the environment (ENV), the user equipment (UE), the CRRM information manager (CRRM-IM), and the CRRM decider (CRRM-D). The clarity of the model enables an efficient investigation of CRRM algorithms based on multi-criteria optimization theory. The integrated cost model makes possible a cost-benefit investigation of different CRRM algorithms and architectures. A hybrid simulation model, where a simulation model and an analytical model operate in parallel over time, leads to low time and memory demands even for the simulation of complex scenarios. Additionally it allows for a convenient and straightforward integration of different analytical models for wireless network technologies. A discrete event simulator named HEKATE is based on this hybrid simulation model which has been implemented using OMNeT++. The scope of the proposed framework is demonstrated by the evaluation of realistic CRRM scenarios for UMTS and GSM/EGPRS

A model for heterogeneous networks management and performance evaluation

In general, modern networks are analysed by taking several Key Performance Indicators (KPIs) into account, their proper balance being required in order to guarantee a desired Quality of Service (QoS), particularly, cellular wireless heterogeneous networks. A model to integrate a set of KPIs into a single one is presented, by using a Cost Function that includes these KPIs, providing for each network node a single evaluation parameter as output, and reflecting network conditions and common radio resource management strategies performance. The proposed model enables the implementation of different network management policies, by manipulating KPIs according to users' or operators' perspectives, allowing for a better QoS. Results show that different policies can in fact be established, with a different impact on the network, e.g., with median values ranging by a factor higher than two

EVEREST IST - 2002 - 00185 : D23 : final report

Deliverable públic 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

Intelligent hybrid cheapest cost and mobility optimization RAT selection approaches for heterogeneous wireless networks

The evolution of wireless networks has led to the deployment of different Radio Access Technologies (RATs) such as UMTS Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE), Wireless Local Area Network (WLAN) and Mobile Worldwide Interoperability for Microwave Access (WiMAX) which are integrated through a common platform. Common Radio Resource Management (CRRM) was proposed to manage radio resource utilization in heterogeneous wireless networks and to provide the required Quality of Service (QoS) for allocated calls. RAT selection algorithms are an integral part of the CRRM algorithms. Their role is to decide, when a new or Vertical Handover (VHO) call is requested, which of the available RATs is most suitable to fit the need of the incoming call and when to admit them. This paper extends our earlier work on the proposed intelligent mobility optimization and proposes an intelligent hybrid cheapest cost RAT selection approach which aims to increase users' satisfaction by allocation users that are looking for cheapest cost connections to a RAT that offers the cheapest cost of service. A comparison for the performance of centralized load-balancing, proposed and distributed cheapest cost and mobility optimization algorithms is presented. Simulation results show that the proposed intelligent algorithms perform better than the centralized load-balancing and the distributed algorithms. © 2014 Academy Publisher