[EN] In today's information society, there is a growing need to access data communication services ubiquitously, with mobility and increasingly higher data rates. This society's demand has motivated the development of the fourth generation of mobile communications (4G) and its evolution towards the fifth generation (5G). This development has required a revolution on the radio interface of the mobile communications systems, and, consequently, has significantly modified their capabilities and their radio resource management. This is the case of the technology known as Long Term Evolution (LTE) and its 4G version called LTE-Advanced. This Doctoral Thesis addresses the modelling, the radio resource management analysis, and the performance evaluation of the downlink of LTE and LTE-Advanced where, among the different features of LTE-Advanced, the focus is on the Coordinated Multi-Point (CoMP) transmission. The Thesis provides a detailed description of the main characteristics of LTE and LTE-Advanced. The high complexity of these systems, has prompted the use of computer simulations as the primary research methodology. The Thesis makes a detailed description of the simulation methodology and the system modelling required, including some contributions of the author in this field. Among them, it is of significant relevance the link-level simulation results used in the European project WINNER + for the LTE evaluation. With regard to the analysis of the radio resource management in LTE, the fundamentals of link adaptation and scheduling are explained in the first place. In relation to the scheduling, the Thesis includes a thorough study of the proportional fairness concept and the suboptimal implementation typically used in LTE to maximize this metric. This study has resulted in a series of ideas embodied in a modification of the typical implementation, which has proved to be capable of increasing the proportional fairness of the resource allocations. Moreover, the link adaptation analysis has revealed the "flash-light" effect problem, which is characterized by a high interference variability due to rapid changes in the scheduling decisions. The Thesis demonstrates that a particular implementation that stabilizes the scheduling decisions can improve the system performance. The radio resource management analysis of this Thesis is completed with the study of CoMP. Specifically, the CoMP scheme studied in this Thesis is a solution with coordinated scheduling and beamforming (CS/CB), that takes into account realistic and robust assumptions concerning the knowledge that the coordinated points have about the channel state. The Thesis proposes this solution for its simplicity and its ability to improve high data rates coverage and capacity even with incomplete channel knowledge. Concerning LTE and LTE-Advanced evaluation, it is performed in two different types of scenarios. On the one hand, the scenarios defined in the process of evaluation of IMT-Advanced. In this framework, it is evaluated the importance of different multi-antenna techniques, including CoMP, considering full-buffer traffic models. The most important conclusions in these scenarios are the significant performance improvement achieved with spatial multiplexing of users and the fact that CoMP mechanisms provide a reduced benefit. The second group of scenarios are those defined by the European project METIS for the evaluation of 5G technologies. Specifically, an indoor office scenario and an outdoor sports stadium have been selected. In these scenarios, a realistic traffic model is used, and it has been demonstrated the utility of CoMP to satisfy the first 5G requirement definitions with feasible frequency bandwidths. In these scenarios with less homogeneous deployments, or with a limited number of transmitters originating the major part of interference, is where this Thesis has found CoMP to be more useful and where the Thesis promotes its use. / [ES] En la actual sociedad, hay una creciente necesidad de acceso a servicios de comunicación de datos de forma ubicua, móvil y a velocidades cada vez más altas. Esta demanda ha motivado el desarrollo de la cuarta generación de comunicaciones móviles (4G) y su evolución hacia la quinta generación (5G). Este desarrollo ha requerido una revolución en la interfaz radio de los sistemas de comunicaciones móviles modificando en gran medida sus capacidades y la forma en la que se gestionan sus recursos. Este es el caso de la tecnología conocida como Long Term Evolution (LTE) y su versión 4G llamada LTE-Advanced. En concreto, esta Tesis Doctoral aborda el modelado, análisis de la gestión de recursos radio y evaluación de prestaciones del enlace descendente de LTE y LTE-Advanced, donde, de entre las características de LTE-Advanced, se ha puesto el foco de atención en la transmisión multipunto coordinada (CoMP). La Tesis proporciona una descripción detallada de las principales características de LTE y LTE-Advanced. La gran complejidad del sistema descrito ha motivado que la metodología de estudio haya sido la simulación mediante ordenador. La Tesis realiza una descripción detallada de dicha metodología y del modelado del sistema empleado, incluyendo algunas aportaciones del autor en este campo. De entre éstas, destaca la provisión de resultados de simulación de nivel de enlace que se usaron en el proyecto europeo WINNER+ para la evaluación de LTE. En cuanto al análisis de la gestión de recursos radio en LTE, en primer lugar, se explican los fundamentos de la adaptación al enlace y el scheduling. En relación con el scheduling, se realiza un estudio del concepto de proportional fairness y de la implementación subóptima típicamente usada en LTE para maximizar esta métrica. Este estudio ha dado como resultado una modificación de la implementación típica que ha demostrado ser capaz de aumentar la proportional fairness en la asignación de recursos con un bajo incremento de complejidad. Además, el análisis de la adaptación al enlace ha revelado el problema del efecto de "luz de flash" consistente en la alta variabilidad de la interferencia debida a rápidos cambios en las decisiones del scheduler. La Tesis demuestra que se pueden mejorar las prestaciones del sistema estabilizando dichas decisiones mediante una implementación concreta. El bloque de análisis de la gestión de recursos se completa con el estudio de CoMP. Específicamente, se estudia una solución con coordinación de scheduling y conformación de haz (CS/CB) que tiene en cuenta suposiciones reales y robustas en cuanto al conocimiento que los puntos coordinados tienen de los canales radio. La Tesis propone esta solución por su sencillez y capacidad de mejorar la eficiencia de los sistemas de comunicaciones móviles, tanto en cobertura de velocidades altas de transmisión como en capacidad, aun teniendo un conocimiento incompleto del canal. En cuanto a la evaluación de LTE y LTE-Advanced, ésta se realiza en dos tipos de escenarios. Por un lado, los escenarios definidos en el proceso de evaluación de IMT-Advanced. En este marco, se evalúa la importancia de diferentes técnicas de transmisión multiantena, incluyendo CoMP, y considerando tráfico de tipo full-buffer. Se ha obtenido una gran mejora de prestaciones por la multiplexación espacial de usuarios y mejoras discretas por el uso de CoMP. El segundo grupo de escenarios son los definidos por el proyecto europeo METIS para evaluación de tecnologías 5G, concretamente se han elegido un escenario de interiores con una oficina, y uno de exteriores con un estadio deportivo. En estos escenarios se utiliza un tráfico realista y se ha demostrado la utilidad de CoMP para mejorar las prestaciones del sistema. En estos escenarios con despliegues menos uniformes, o con un número limitado de transmisores provocando la mayor parte de la interferencia, es donde esta Tesis ha encontrado la mayor u / [CAT] En l'actual societat de la informació, hi ha una creixent necessitat d'accés a serveis de comunicació de dades de forma ubiqua, mòbil i a velocitats cada vegada més altes. Aquesta demanda de la societat, ha motivat el desenrotllament de la quarta generació de comunicacions mòbils (4G) i la seua evolució cap a la quinta generació (5G). Aquest desenrotllament ha requerit una revolució en la interfície ràdio dels sistemes de comunicacions mòbils i ha modificat en gran manera les seues capacitats i la forma en què es gestionen els seus recursos. Aquest és el cas de la tecnologia coneguda com a Long Term Evolution (LTE) i la seua versió 4G anomenada LTE-Advanced. En concret, aquesta Tesi Doctoral aborda el modelatge, anàlisi de la gestió de recursos ràdio i avaluació de prestacions de l'enllaç descendent de LTE i LTE-Advanced, on, d'entre les característiques de LTE-Advanced, s'ha posat el centre d'atenció en la transmissió multipunt coordinada (CoMP). La Tesi proporciona una descripció detallada de les principals característiques de LTE i LTE-Advanced. La gran complexitat del sistema descrit ha motivat que la metodologia d'estudi s'haja basat en simulació per mitjà d'ordinador. La Tesi realitza una descripció detallada de la metodologia de simulació i del modelatge del sistema empleat, incloent-hi algunes aportacions de l'autor en aquest camp. D'entre aquestes, destaca la provisió de resultats de simulació de nivell d'enllaç que es van usar en el projecte europeu WINNER+ per a l'avaluació de LTE. Pel que fa a l'anàlisi de la gestió de recursos ràdio en LTE, en primer lloc, s'expliquen els fonaments de l'adaptació a l'enllaç i el scheduling. En relació amb el scheduling, es realitza un estudi del concepte de proportional fairness i de la implementació subòptima típicament usada en LTE per a maximitzar aquesta mètrica. L'estudi ha donat com a resultat una modificació de la implementació típica que ha demostrat ser capaç d'augmentar la proportional fairness en l'assignació de recursos amb un baix increment de complexitat. A més, l'anàlisi de l'adaptació a l'enllaç ha desvetllat el problema de l'efecte de "llum de flaix" consistent en la alta variabilitat de la interferència deguda a una ràpida variació de les assignacions de recursos. La Tesi demostra que es poden millorar les prestacions del sistema estabilitzant les decisions del scheduler mitjançant una implementació concreta. En el bloc d'anàlisi de la gestió de recursos d'aquesta Tesi es completa amb l'estudi de CoMP. Específicament, s'estudia una solució amb coordinació de scheduling i conformació de feix (CS/CB), que té en compte suposicions reals i robustes quant al coneixement que els punts coordinats tenen dels canals ràdio dels usuaris servits. La Tesi proposa aquesta solució per la seua senzillesa i capacitat de millorar l'eficiència dels sistemes de comunicacions mòbils, tant en cobertura de velocitats altes de transmissió com en capacitat, encara tenint un coneixement incomplet del canal. Quant a l'avaluació de LTE i LTE-Advanced, aquesta es realitza en dos tipus d'escenaris diferents. D'una banda, els escenaris definits dins del procés d'avaluació de tecnologies IMT-Advanced. Dins d'aquest marc, s'avalua la importància de diferents tècniques de transmissió multi-antena, incloent-hi CoMP, i considerant tràfic de tipus full-buffer. S'ha obtingut una gran millora de prestacions amb la multiplexació espacial d'usuaris i una discreta millora amb CoMP. El segon grup d'escenaris són els definits pel projecte europeu METIS per a l'avaluació de tecnologies 5G, concretament s'han triat un escenari d'interiors amb una oficina, i un d'exteriors amb un estadi esportiu, on s'ha utilitzat un tràfic realista. En aquests escenaris amb desplegaments menys uniformes, o amb un nombre limitat de transmissors provocant la major part de la interferència, és on aquesta Tesi ha trobat la utilitat més gran de / Martín-Sacristán Gandía, D. (2016). 3GPP Long Term Evolution: Performance Analysis and Evolution towards 4G with Coordinated Multi-Point Transmission [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63261 / TESIS

This master’s thesis deals with a UMTS radio access network optimization, containing radio interface analysis, services and procedures description, ways to correct parameters calculations and settings and other issues necessary for a correct access network operation. The goal is effective network operation, minimum costs and maximum performance and flexibility of the network. The optimization during system operation is important because of the system character. The UMTS system uses the WCDMA technology, where particular users share the same frequency band and they are distinguished from one another via code sequences. The capacity of such a system is then given by the interference level - each particular user increases the interference level by the value corresponding to his transmit power. The maximum cell capacity is determined by the maximum interference level at which users can still operate with required services, so it is related not only to the number of users, but also to their bit rate. The optimization allows effective usage of the system for different services with different requirements. The main optimization tool is the radio resource management, containing number of algorithms, such as admission control, which decides the acceptance or rejection of a new user demanding certain service, power control, which ensure that users transmit with a minimal power sufficient for required service, handover and cell selection algorithms etc. The major parameter used by these algorithms is a cell load factor, which is related to the interference level margin. There are several methods for the load factor estimation and some of them are described in this work. Some other optimization techniques are mentioned here, too. This work also contains a laboratory exercise proposal for radio resource management introduction using the OPNET Modeler network simulation tool.

Face à la croissance exponentielle des réseaux mobiles très haut débit, les opérateurs de téléphonie mobile se sont lancé dans le déploiement des réseaux dits hiérarchiques (HetNet), composés par des sous-réseaux avec des caractéristiques divergentes en termes de type des cellules déployées et des technologies d’accès radio utilisées. Avec ce caractère hétérogène des réseaux cellulaire, l’exploitation de ces derniers devienne de plus en plus compliquée et coûteuse impliquant le déploiement, la configuration et la reconfiguration de stations de base et d’équipements de différentes caractéristiques. Ainsi, l’intégration dans les réseaux HetNet de fonctionnalités d’auto-configuration automatisant et simplifiant l’exploitation des réseaux deviennent une demande forte des opérateurs. Cette thèse a pour objectif l’étude et le développement de solutions de gestion dynamique de l’équilibrage de charges entre les différentes couches composant un même HetNet, pour une expérience utilisateur (QoE) améliorée. Dans ce contexte, une classe des algorithmes d’équilibrage de charges dite ‘équilibrage de charges par adaptation dynamique des paramètres de la procédure de handover’ est étudiée. Pour commencer, nous développons un modèle théorique basé sur des solutions et des outils de la géométrie stochastique et incorporant le caractère hétérogène des réseaux cellulaires. Ensuite nous exploitons ce modèle pour introduire des algorithmes d’adaptation des paramètres de handover basés sur la maximisation de la puissance reçue et du rapport signal/brouillage plus bruit (SINR). Nous exploitons ces résultats pour implémenter et étudier, par simulation à évènements discrets, des algorithmes d’équilibrage de charges dans le contexte des réseaux LTE HetNet auto-organisés basés sur les spécifications 3GPP. Ces travaux soulignent l’importance de l’équilibrage de charges afin de booster les performances des réseaux cellulaires en termes de débit global transmis, perte de paquets de données et utilisation optimisée des ressources radio. / High demands on mobile networks provide a fresh opportunity to migrate towardsmulti-tier deployments, denoted as heterogeneous network (HetNet), involving a mix of cell types and radio access technologies working together seamlessly. In this context, network optimisation functionalities such as load balancing have to be properly engineered so that HetNet benefit are fully exploited. This dissertation aims to develop tractable frameworks to model and analyze load balancing dynamics while incorporating the heterogeneous nature of cellular networks. In this context we investigate and analyze a class of load balancingstrategies, namely adaptive handover based load balancing strategies. These latter were firstly studied under the general heading of stochastic networks using independent and homogeneous Poisson point processes based network model. We propose a baseline model to characterize rate coverage and handover signalling in K-tier HetNet with a general maximum power based cell association and adaptive handover strategies. Tiers differ in terms of deployment density and cells characteristics (i.e. transmit power, bandwidth, and path loss exponent). One of the main outcomes is demonstrating the impact of offloading traffic from macro- to small-tier. This impact was studied in terms of rate coverage and HO signalling. Results show that enhancement in rate coverage is penalized by HO signalling overhead. Then appropriate algorithms of LB based adaptive HO are designed and their performance is evaluated by means of extensive system level simulations. These latter are conducted in 3GPP defined scenarios, including representation of mobility procedures in both connectedstate. Simulation results show that the proposed LB algorithms ensure performance enhancement in terms of network throughput, packet loss ratio, fairness and HO signalling.

In wireless communication systems, one of the most important resources being focused on all the researchers is spectrum. A cognitive radio (CR) system is one of the efficient ways to access the radio spectrum opportunistically, and efficiently use the available underutilized licensed spectrum. Spectrum utilization can be significantly enhanced by developing more applications with adopting CR technology. CR systems are implemented using a radio technology called software-defined radios (SDR). SDR provides a flexible and cost-effective solution to fulfil the requirements of end users. We can see a lot of innovations in Internet of Things (IoT) and increasing number of smart devices. Hence, a CR system application involving an IoT device is studied in this thesis. Opportunistic spectrum access involves two tasks of CR system: spectrum sensing and dynamic spectrum access. The functioning of the CR system is rest upon the spectrum sensing. There are different spectrum sensing techniques used to detect the spectrum holes and a few of them are discussed here in this thesis. The simplest and easiest to implement energy detection spectrum sensing technique is used here to implement the CR system. Dynamic spectrum access involves different models and strategies to access the spectrum. Amongst the available models, an interweave model is more challenging and is used in this thesis. Interweave model needs effective spectrum sensing before accessing the spectrum opportunistically. The system designed and simulated in this thesis is capable of transmitting an output from an IoT device using USRP and GNU radio through accessing the radio spectrum opportunistically.

In the current mobile telecommunication market, with slow growth in mobile subscriptions and increasing traffi demand, each mobile operator needs to manage their customer loyalty in order to maintain position in the market. To retain their customer's loyalty, the user quality of satisfaction needs to be preserved. Integrating a Quality of Experience (QoE) approach into a radio resource scheduling scheme can be a means to improve user quality of satisfaction to a service. However, the enhancement of existing resource allocation management to support a QoE-based resource scheduling scheme needs a careful consideration since it will impact the mobile operator's investment cost. A profitability assessment of QoE-based resource allocation is required as a basis for the mobile operator to forecast their potential benefit of QoE-based resource scheduling deployment. This thesis investigated the profitability of deploying QoE-based radio resource management (RRM) in terms of revenue loss compared to proportional fair (PF) scheduling, a widely used resource allocation scheme, in delivering a streaming video service. In QoE-based RRM, a buffering percentage experienced by a user was considered in the resource allocation decision process. The two scheduling schemes were simulated in different network configurations. User satisfaction was quantified in terms of mean opinion score. Given the degree of satisfaction for each user, a number of users who would be likely to churn was obtained. A cost-benefit assessment was then conducted by predicting revenue loss due to customer churn. The results from the simulation and cost analysis show that although QoE-based resource scheduling provides users with a higher degree of satisfaction for more base stations, the utilization of a QoE-based resource scheduler does not offer significant benefit to the network operator with regard to revenue loss and deployment cost when compared to a PF scheduler. This outcome indicates that if the business target is to reduce customer churn, then the operator should utilize a PF scheduler for their RRM scheme. / Den nuvarande mobiltelefonimarknaden kännetecknas av svag tillväxt av nya kunder men ett ökat nyttjande bland existerande kunder av företagens tjänster. Kundlojalitet har blivit en avgörande faktor för att uppnå en stark marknadsposition. Kundernas upplevda kvalitet utav mobiltjänsterna behöver upprätthållas på en hög nivå för att tillfredställa denna lojalitet. Att applicera en upplevad kvalitet (QoE) metod i en radio resurs kan vara ett medel till att förbättra kundernas upplevda kvalitet av mobiltj änsten. För att undersöka ifall en sådan tjänst är lönsam är det dock nödvändigt att en lönsamhetskalkyl genomförs, där investeringskostnad och systemets driftkostnad vägs mot eventuella intäkter. En lönsamhetsbedömning av QoE-baserad resursallokering krävs som grund för mobiloperatören att förutse deras potentiella fördelar med QoE-baserad resursschemaläggning. Denna uppsats undersöker lönsamheten av att implementera QoE i termer av förlorade intäkter, jämfört med proportionell rättvis (PF) schemaläggning, i att leverera en videoströmservice. I QoE-baserad RRM användes buffertprocentandel som användes av användarna i resursallokeringsprocessen.  De två olika systemen simulerades genom att använda olika antal basstationer i mobilnätverkskonfigurationen. Användarnöjdhet kvantifierades genom att låta användarna betygsätta tjänsten, detta värde användes därefter till att uppskatta hur många av kunderna som sannolikt ej skulle återanvända tjänsten. En lönsamhetskalkyl genomfördes genom att prediktera förlorade intäkter med avseende på kunderna som ej skulle återanvända tjänsten. Resultaten från simulerings- och lönsamhetsberäkningen visade att även om QoE erbjuder en högre kundnöjdhet av tjänsten och tillfredsställelse för er basstationer, så leder inte en QoE-implementering till signikanta fördelar för nätverket i termer av förlorade intäkter och investeringskostnader jämfört med ett PF schemaläggare. Detta indikerar att om ett företags mål är att höja kundlojaliteten, då skall företaget applicera en PF schemaläggare istället för QoE.

The next generation wireless system (NGWS) has been conceived as a ubiquitous wireless environment. It integrates existing heterogeneous access networks, as well as future networks, and will offer high speed data, real-time applications (e.g. Voice over IP, videoconference ) and real-time multimedia (e.g. real-time audio and video) support with a certain Quality of Service (QoS) level to mobile users. It is required that the mobile nodes have the capability of selecting services that are offered by each provider and determining the best path through the various networks. Efficient radio resource management (RRM) is one of the key issues required to support global roaming of the mobile users among different network architectures of the NGWS and a precise call admission control (CAC) scheme satisfies the requirements of high network utilization, cost reduction, minimum handover latency and high-level QoS of all the connections. This thesis is going to describe an adaptive class-based CAC algorithm, which is expected to prioritize the arriving channel resource requests, based on user¿s classification and channel allocation policy. The proposed CAC algorithm couples with Fuzzy Logic (FL) and Pre-emptive Resume (PR) theories to manage and improve the performance of the integrated wireless network system. The novel algorithm is assessed using a mathematical analytic method to measure the performance by evaluating the handover dropping probability and the system utilization.

The architecture of mobile networks has dramatically evolved in order to fulfill the growing demands on wireless services and data. The radio resources, which are used by the current mobile networks, are limited while the users demands are substantially increasing. In the future, tremendous Internet applications are expected to be served by mobile networks. Therefore, increasing the capacity of mobile networks has become a vital issue. Heterogeneous networks (HetNets) have been considered as a promising paradigm for future mobile networks. Accordingly, the concept of small cell has been introduced in order to increase the capacity of the mobile networks. A femtocell network is a kind of small cell networks. Femtocells are deployed within macrocells coverage. Femtocells cover small areas and operate with low transmission power while providing high capacity. Also, UEs can be offloaded from macrocells to femtocells. Thus, the capacity can be increased. However, this will introduce different technical challenges. The interference has become one of the key challenges for deploying femtocells within a certain macrocells coverage. Undesirable impact of the interference can degrade the performance of the mobile networks. Therefore, radio resource management mechanisms are needed in order to address key challenges of deploying femtocells. The objective of this work is to introduce radio resource control approaches, which are used to increase mobile networks' capacity and alleviate undesirable impact of the interference. In addition, proposed radio resource control approaches ensure the coexistence between macrocell and femtocells based on LTE-Advanced environment. Firstly, a novel mechanism is proposed in order to address the interference challenge. The proposed approach mitigates the impact of interference based on controlling radio sub-channels' assignment and dynamically adjusting the transmission power. Secondly, a dynamic strategy is proposed for the FFR mechanism. In the FFR mechanism, the whole spectrum is divided into four fixed sub-channels and each sub-channel is assigned for a different sub-area after splitting the macrocell coverage area into four sub-areas. The objective of the proposed scheme is to divide the spectrum dynamically based on the QoS indicators for each sub-area. Lastly, a novel packet scheduling scheme is proposed to improve the performance of femtocell networks. The proposed scheduling strategy assigns radio resources based on two objectives: increasing the network capacity and achieving better fairness among attached UEs.

No / In the telecommunication networks the introduction of Next Generation Wireless Networks (NGWN) has been described as the most significant change in wireless communication. The convergence of different access networks in NGWN allows generalized mobility, consistency and ubiquitous provision of services to mobile users. The general target of NGWN is to transport different types of information like voice, data, and other media like video in packets form like IP. The NGWNs offer significant savings in costs to the operators along with new and interesting services to the consumers. Major challenges in NGWN are efficient resource utilization, maintaining service quality, reliability and the security. This paper proposes a solution for seamless load aware Radio Access Technology (RAT) selection based on interworking of different RATs in NGWN. In this paper novel load balancing algorithms have been proposed which have been simulated on the target network architecture for TCP data services. The IEEE 802.21 Media Independent Handover (MIH) is utilized in load balancing specifically for mobility management, which enable low handover latency by reducing the target network detection time. The proposed method considers the network type, signal strength, data rate and network load as primary decision parameters for RAT selection process and consists of two different algorithms, one located in the mobile terminal and the other at the network side. The network architecture, the proposed load balancing framework and RAT selection algorithms were simulated using NS2. Different attributes like load distribution in the wireless networks and average throughput to evaluate the effects of load balancing in considered scenarios.

No / The ever increasing user QoS demands and emergence of new user applications make job of network operators and manufacturers more challenging for efficiently optimisation and managing radio resources in radio the radio resources pools of different wireless networks. A group of strategies or mechanisms which are collectively responsible for efficient utilisation of radio resources available within the Radio Access Technologies (RAT) are termed as Radio Resource Management (RRM). The traditional RRM strategies are implemented independently in each RAT, as each RRM strategy considers attributes of a particular access technology. Therefore traditional RRM strategies are not suitable for heterogeneous wireless networks. Common Radio Resource Management (CRRM) or joint radio resource management (JRRM) strategies are proposed for coordinating radio resource management between multiple RATs in an improved manner. In this paper a fuzzy algorithm based CRRM strategy is presented to efficiently utilise the available radio resources in heterogeneous wireless networks. The proposed CRRM strategy balances the load in heterogeneous wireless networks and avoids the unwanted congestion situation. The results such as load distribution, packet drop rate and average throughput at mobile nodes are used to demonstrate the benefits of load balancing in heterogeneous wireless networks using proposed strategy.

Third Generation (3G) wireless networks have been well studied and optimized with traditional radio resource management techniques, but still there is room for improvement. Cognitive radio technology can bring significantcant network improvements by providing awareness to the surrounding radio environment, exploiting previous network knowledge and optimizing the use of resources using machine learning and artificial intelligence techniques. Cognitive radio can also co-exist with legacy equipment thus acting as a bridge among heterogeneous communication systems. In this work, an approach for applying cognition in wireless networks is presented. Also, two machine learning techniques are used to create a hybrid cognitive engine. Furthermore, the concept of cognitive radio resource management along with some of the network applications are discussed. To evaluate the proposed approach cognition is applied to three typical wireless network problems: improving coverage, handover management and determining recurring policy events. A cognitive engine, that uses case-based reasoning and a decision tree algorithm is developed. The engine learns the coverage of a cell solely from observations, predicts when a handover is necessary and determines policy patterns, solely from environment observations. / Ph. D.