<p>The increasing usage of information technology in military affairs raises the need for robust high capacity radio networks. The network will be used to provide several different types of services, for example group calls and situation awareness services. All services have specific demands on packet delays and packet losses in order to be fully functional, and therefore there is a need for a Quality of Service (QoS) mechanism in the network. </p><p>In this master thesis we examine the possibility to provide a QoS mechanism in Ad Hoc networks by using priority queues. The study includes two different queuing schemes, namely fixed priority queuing and weighted fair queuing. The performance of the two queuing schemes are evaluated and compared with respect to the ability to provide differentiation in network delay, i.e., provide high priority traffic with lower delays than low priority traffic. The study is mainly done by simulations, but for fixed priority queuing we also derive a analytical approximation of the network delay. </p><p>Our simulations show that fixed priority queuing provides a sharp delay differentiation between service classes, while weighted fair queuing gives the ability to control the delay differentiation. One of those queuing schemes alone might not be the best solution for providing QoS, instead we suggest that a combination of them is used.</p>

<p>With the Internet expansion, real-time transmission over Internet is becoming a new promising application. Successful real-time communication over IP networks requires reasonably reliable, low delay, low loss date transport. Since Internet is a non-synchronous packet switching network, high load and lack of guarantees on data delivery make real-time communication such as Voice and Video over IP a challenging application to become realistic on the Internet. </p><p>This thesis work is composed of two parts within real-time voice and video communication: network simulation and measurement on the real Internet. In the network simulation, I investigate the requirement for the network"overprovisioning"in order to reach certain quality-of-service. In the experiments on the real Internet, I simulate real-time transmission with UDP packets along two different traffic routes and analyze the quality-of- service I get in each case. </p><p>The overall contribution of this work is: To create scenarios to understand the concept of overprovisioning and how it affects the quality-of-service. To develop a mechanism to measure the quality-of-service for real-time traffic provided by the current best-effort network.</p>

No description available.

This thesis investigates designs that enable individual components of a distributed system to work together and coordinate their actions towards a common goal. While the basic motivation for our research is to develop engineering principles for large-scale autonomous systems, we address the problem in the context of resource management in server clusters that provide web services. To this end, we have developed, implemented and evaluated a decentralized design for resource management that follows four principles. First, in order to facilitate scalability, each node has only partial knowledge of the system. Second, each node can adapt and change its role at runtime. Third, each node runs a number of local control mechanisms independently and asynchronously from its peers. Fourth, each node dynamically adapts its local configuration in order to optimize a global utility function. The design includes three fundamental building blocks: overlay construction, request routing and application placement. Overlay construction organizes the cluster nodes into a single dynamic overlay. Request routing directs service requests towards nodes with available resources. Application placement partitions the cluster resources between applications, and dynamically adjusts the allocation in response to changes in external load, node failures, etc. We have evaluated the design using complexity analysis, simulation and prototype implementation. Using complexity analysis and simulation, we have shown that the system is scalable, operates efficiently in steady state, quickly adapts to external events and allows for effective service differentiation by a system administrator. A prototype has been built using accepted technologies (Java, Tomcat) and evaluated using standard benchmarks (TPC-W and RUBiS). The evaluation results show that the behavior of the prototype matches closely that of the simulated design for key metrics related to adaptability and robustness, therefore validating our design and proving its feasibility. / QC 20100629

In today’s world, there is a strong competition between companies. In this competition environment, it is accepted that one of the most important elements is quality for companies to be differentiated. The company which can produce high quality products or high quality services can survive in this competition. Nevertheless, the situations of being high quality or low quality depends on the tolerance limits which are determined by customers and it can be changed from person to person. In today’s world, even though, when quality concept is considered, the first thing that comes to the minds is “the quality of products”, the fact of quality is not important for only manufacturing companies but also service companies. To be able to comprehend that if the products or the services which are provided by the company satisfy the customers’ needs, the quality should be measured. Nevertheless, when the process of measuring the quality is carried out by experiments, observations and tangible data in the manufacturing companies, there is no tangible data in the service companies to measure the quality. That’s why there are many different models and qualitative approaches that are developed to be able to measure the quality in service companies. In the scope of this thesis, a model has been developed to measure the current quality and evaluate the perceived quality of a healthcare company. Developed model is consisted of two main parts which are functional quality and technical quality. Besides, for determining the perceived quality, socio-demographic attributes are also considered. To be able to implement the functional quality part of the model, a survey has been created about the clinic and it has been sent to the patients. And the data about the perceived quality has been gathered from the patients. To be able to implement the technical quality part of the model, interviews with the staff of the clinic have been made and the studies to improve the perceived quality of the clinic, permissions and certificates are identified. Developed model has been tested in the case company and it has been found acceptable. The model ensures to measure the current service quality of the clinic and unveils the areas which cause the low quality in the clinic. Thus, the spots that need to be improved are identified.

University of Macau / Faculty of Business Administration / Department of Management and Marketing

Les xarxes IP tradicionals utilitzen el model de transmissió "best-effort" per transportar tràfic entre clients de la xarxa. Aquest model de transmissió de tràfic no és el més adequat per les aplicacions en temps real com per exemple, vídeo sota demanda, conferències multimedia o realitat virtual que per altra banda tenen cada cop més adeptes entre els clients de la xarxa. A fi de garantir el correcte funcionament d'aquest tipus d'aplicacions, l'estructura de la xarxa ha de ser substancialment modificada amb l'objectiu final de poder optimitzar els seus propis recursos i així poder fer front a aquells tipus de tràfics i de clients que requereixen certes garanties de "Qualitat de Servei" (QoS) per a la seva correcta transmissió.Aquestes modificacions o millores de la xarxa poden ser perfectament realitzades sota l'entorn d'Enginyeria de Tràfic (Traffic Engineering, TE). Dos són els principals aspectos relacionats amb el funcionament de la xarxa en aquest entorn de TE: els mecanismes de commutació i els mecanismes d'encaminament. Així, per una banda es necessita un mecanisme de commutació molt ràpid en els nodes interns de la xarxa a fi de que els paquets de dades puguin ser processats amb el menor temps possible. En xarxes IP aquest objectiu s'aconsegueix amb el Multiprotocol Label Switching (MPLS). Per altra banda, a fi de garantir certa QoS, les decisions d'encaminament s'han de realitzar tenint en compte quines són les restriccions de QoS sol·licitades per el node client que origina el tràfic. Aquest objectiu s'aconsegueix modificant els esquemes d'encaminament tradicionals, incorporant-hi els paràmetres de QoS en les decisions d'encaminament, generant el que es coneix com algorismes d'encaminament amb QoS (QoS routing).Centrant-nos en aquest darrer aspecte, la majoria dels algorismes d'encaminament amb QoS existents, realitzen la selecció de la ruta a partir de la informació d'estat de l'enllaç emmagatzemada en les bases de dades d'estat de l'enllaç contingudes en els nodes. Per poder garantir que els successius canvis en l'estat de la xarxa estiguin perfectament reflectits en aquesta informació d'encaminament, el protocol d'encaminament ha d'incloure un mecanisme d'actualització que faci possible garantir que la selecció de les rutes es fa a partir d'informació acurada de l'estat real de la xarxa. En un entorn IP tradicional, el qual inicialment no inclou paràmetres de QoS, els canvis produïts en la informació d'encaminament són tan sols deguts a modificacions en la topologia i connectivitat de la xarxa. En aquest entorn, donat que la freqüència en la qual s'espera rebre missatges advertint d'aquestes modificacions no és elevada, la majoria dels mecanismes d'actualització es basen en la inclusió d'un cert període de refresc. Així, les bases de dades s'actualitzen periòdicament mitjançant la distribució d'uns missatges que informen a la resta de nodes de l'estat de la xarxa,a fi de que cada node pugui actualitzar la seva base de dades.No obstant això, hem de tenir en compte que en aquelles xarxes IP/MPLS altament dinàmiques amb requeriments de QoS, aquest mecanisme d'actualització basat en un refresc periòdic no serà útil. Això és degut a la rigidesa que presenta aquest mecanisme, la qual fa que no sigui aplicable a un entorn que presenti contínues variacions del paràmetres dels enllaços cada cop que s'estableixi o s'alliberi una connexió (ara a més de la topologia i connectivitat, s'inclouen paràmetres de QoS, com ampla de banda, retard, variació del retard, etc.). Per tot això, s'haurà de generar un mecanisme d'actualització molt més eficient que sigui capaç de mantenir les bases de dades dels nodes perfectament actualitzades reflectint els continus canvis en l'estat de la xarxa. L'alta granularitat d'aquest mecanisme provocarà una sobrecàrrega de la xarxa, degut a l'enorme quantitat de missatges d'actualització que seran necessaris per poder mantenir informació actualitzada en les bases de dades d'estat de l'enllaç en cada node.Per reduir aquesta sobrecàrrega de senyalització apareixen les polítiques d'activació (triggering policies) que tenen per objectiu determinar en quin moment un node ha d'enviar un missatge d'actualització a la resta de nodes de la xarxa advertint-los de les variacions produïdes en els seus enllaços. Desafortunadament, l'ús d'aquestes polítiques d'activació produeix un efecte negatiu sobre el funcionament global de la xarxa. En efecte, si l'actualització de la informació de l'estat de l'enllaç en els nodes no es fa cada cop que aquesta informació es veu modificada, sinó que es fa d'acord a una certa política d'activació, no es podrà garantir que aquesta informació representi de forma acurada l'esta actual de la xarxa en tot moment. Això pot provocar una selecció no òptima de la ruta seleccionada i un increment en la probabilitat de bloqueig de noves connexions a la xarxa. / Las redes IP tradicionales utilizan el modelo de transmisión best-effort para transportar tráfico entre clientes de la red. Es bien sabido que este modelo de transmisión de tráfico no es el más adecuado para las aplicaciones en tiempo real, tales como video bajo demanda, conferencias multimedia o realidad virtual, que cada vez son más de uso común entre los clientes de la red. Para garantizar el correcto funcionamiento de dichas aplicaciones la estructura de la red debe ser modificada a fin de optimizar la utilización de sus propios recursos y para poder hacer frente a aquellos tráficos que requieran ciertas garantías de Calidad de Servicio (QoS) para su correcta transmisión.Estas modificaciones o mejoras de la red pueden ser perfectamente realizadas bajo el entorno de Traffic Engineering (TE). Dos son los principales aspectos relacionados con el funcionamiento de la red en el entorno de TE: los mecanismos de conmutación y los mecanismos de encaminamiento. Así, por una parte, se necesita un mecanismo de conmutación muy rápido en los nodos intermedios de la red a fin de que los paquetes de datos puedan ser procesados con el menor tiempo posible. En redes IP este objetivo se consigue con el Multiprotocol Label Switching (MPLS). Por otra parte a fin de garantizar cierta QoS, las decisiones de encaminamiento se deben realizar acorde con los parámetros de QoS requeridos por el cliente que origina tráfico. Este objetivo se consigue modificando los esquemas de encaminamiento tradicionales e incorporando parámetros de QoS en las decisiones de encaminamiento, lo que deriva en la generación de encaminamiento con QoS (QoS routing).Centrándonos en este último aspecto de encaminamiento, la mayoría de los algoritmos de QoS routing existentes realizan la selección de la ruta a partir de la información de estado del enlace que está almacenada en las bases de datos de estado del enlace contenidas en los nodos. A fin de garantizar que los sucesivos cambios en el estado de la red estén perfectamente reflejados en dicha información, el mecanismo de encaminamiento debe incorporar un mecanismo de actualización cuyo objetivo sea garantizar que las decisiones de encaminamiento se realizan a partir de información fidedigna del estado de la red. En un entorno IP tradicional, el cual no incluye parámetros de QoS, los cambios producidos en dicha información son los debidos a modificaciones en la topología y conectividad. En dicho entorno dado que no son esperadas frecuentes variaciones de la topología de la red, la mayoría de los mecanismos de actualización están basados en la inclusión de un cierto periodo de refresco.Sin embargo, en redes IP/MPLS altamente dinámicas con requerimientos de QoS, este mecanismo de actualización no será adecuado debido a su rigidez y a las continuas variaciones de los parámetros de los enlaces (que ahora incluirá parámetros de QoS, tales como, ancho de banda, retardo, variación del retado, etc.) que se producirán cada vez que se establezca/libere una conexión. Por tanto, se deberá generar un mecanismo de actualización mucho más eficiente que sea capaz de actualizar las bases de datos de los nodos a fin de reflejar las constantes variaciones del estado de la red. La alta granularidad de este mecanismo provocará una sobrecarga de la red, debido a la enorme cantidad de mensajes de actualización necesarios para mantener información actualizada del estado de la red. Para reducir esta sobrecarga de señalización aparecen las políticas de disparo (triggering policies), cuyo objetivo es determinar en qué momento un nodo debe enviar un mensaje de actualización al resto de nodos de la red advirtiéndoles de las variaciones producidas en sus enlaces.Desafortunadamente el uso de dichas políticas de disparo produce un efecto negativo sobre el funcionamiento global de la red. En efecto, si la actualización de la información de estado del enlace en los nodos no se realiza cada vez que dicha información es modificada sino de acuerdo con cierta política de disparo, no se puede garantizar que dicha información represente fielmente el estado de la red. Así, la selección de la ruta, podrá ser realizada basada en información inexacta o imprecisa del estado de lo red, lo cual puede provocar una selección no óptima de la ruta y un incremento en la probabilidad de bloqueo de la red.Esta Tesis se centra en definir y solucionar el problema de la selección de rutas bajo información inexacta o imprecisa de la red (routing inaccuracy problem). Se consideran dos escenarios de trabajo, las actuales redes MPLS y las futuras redes WDM, para los cuales se propone un nuevo mecanismo de encaminamiento: BYPASS Based Routing (BBR) para redes IP/MPLS y BYPASS Based Optical Routing (BBOR) para redes WDM. Ambos mecanismos de encaminamiento se basan en un concepto común denominado "bypass dinámico".El concepto de "bypass dinámico" permite que un nodo intermedio de la red encamine el mensaje de establecimiento que ha recibido del nodo fuente, a través de una ruta distinta a la calculada por el nodo fuente (y explícitamente indicada en el mensaje de establecimiento), cuando detecte que inesperadamente el enlace de salida no dispone de recursos suficientes para soportar las garantías de QoS requeridas por la conexión a establecer. Estas rutas alternativas, denominadas bypass-paths, son calculadas por el nodo fuente o de entrada a la red simultáneamente con la ruta principal para ciertos nodos intermedios de la misma. En redes IP/MPLS el mecanismo BBR aplica el concepto de "bypass dinámico" a las peticiones de conexión con restricciones de ancho de banda. En cambio, en redes WDM, el mecanismo BBOR aplica el concepto de "bypass dinámico" a la hora de asignar una longitud de onda por la cual se va a transmitir el trafico. / Traditional IP networks are based on the best effort model to transport traffic flowsbetween network clients. Since this model cannot properly support the requirements demanded by several emerging real time applications (such as video on demand, multimedia conferences or virtual reality), some modifications in the network structure, mainly oriented to optimise network performance, are required in order to provide Quality of Service (QoS) guarantees.Traffic Engineering is an excellent framework to achieve these network enhancements.There are two main aspects in this context that strongly interact with network performance: switching mechanisms and routing mechanisms. On one hand, a quick switching mechanism is required to reduce the processing time in the intermediate nodes. In IP networks this behaviour is obtained by introducing Multiprotocol Label Switching (MPLS). On the other hand, a powerful routing mechanism that includes QoS attributes when selecting routes (QoS Routing) is also required.Focusing on the latter aspect, most QoS routing algorithms select paths based on the information contained in the network state databases stored in the network nodes. Because of this, routing mechanisms must include an updating mechanism to guarantee that the network state information perfectly represents the current network state. Since network state changes (topology) are not produced very often, in conventional IP networks without QoS capabilities, most updating mechanisms are based on a periodic refresh.In contrast, in highly dynamic large IP/MPLS networks with QoS capabilities a finer updating mechanism is needed. This updating mechanism generates an important and nondesirablesignalling overhead if maintaining accurate network state information is pursued. To reduce the signalling overhead, triggering policies are used. The main function of a triggering policy is to determine when a network node must advertise changes in its directly connected links to other network nodes. As a consequence of reduced signalling, the information in the network state databases might not represent an accurate picture of the actual network state.Hence, path selection may be done according to inaccurate routing information, which could cause both non-optimal path selection and an increase in connection blocking frequency.This Thesis deals with this routing inaccuracy problem, introducing new mechanisms to reduce the effects on global network performance when selecting explicit paths under inaccurate routing information. Two network scenarios are considered, namely current IP/MPLS networks and future WDM networks, and one routing mechanism per scenario is suggested:BYPASS Based Routing (BBR) for IP/MPLS and BYPASS Based Optical Routing (BBOR) for WDM networks. Both mechanisms are based on a common concept, which is defined as dynamic bypass.According to the dynamic bypass concept, whenever an intermediate node along the selected path (unexpectedly) does not have enough resources to cope with the incoming MPLS/optical-path demand requirements, it has the capability to reroute the set-up message through alternative pre-computed paths (bypass-paths). Therefore, in IP/MPLS networks the BBR mechanism applies the dynamic bypass concept to the incoming LSP demands under bandwidth constraints, and in WDM networks the BBOR mechanism applies the dynamic bypass concept when selecting light-paths (i.e., selecting the proper wavelength in both wavelength selective and wavelength interchangeable networks). The applicability of the proposed BBR and the BBOR mechanisms is validated by simulation and compared with existing methods on their respective network scenarios. These network scenarios have been selected so that obtained results may be extrapolated to a realistic network.

The evolution of microprocessor design in the last few decades has changed significantly, moving from simple inorder single core architectures to superscalar and vector architectures in order to extract the maximum available instruction level parallelism. Executing several instructions from the same thread in parallel allows significantly improving the performance of an application. However, there is only a limited amount of parallelism available in each thread, because of data and control dependences. Furthermore, designing a high performance, single, monolithic processor has become very complex due to power and chip latencies constraints. These limitations have motivated the use of thread level parallelism (TLP) as a common strategy for improving processor performance. Multithreaded processors allow executing different threads at the same time, sharing some hardware resources. There are several flavors of multithreaded processors that exploit the TLP, such as chip multiprocessors (CMP), coarse grain multithreading, fine grain multithreading, simultaneous multithreading (SMT), and combinations of them.To improve cost and power efficiency, the computer industry has adopted multicore chips. In particular, CMP architectures have become the most common design decision (combined sometimes with multithreaded cores). Firstly, CMPs reduce design costs and average power consumption by promoting design re-use and simpler processor cores. For example, it is less complex to design a chip with many small, simple cores than a chip with fewer, larger, monolithic cores.Furthermore, simpler cores have less power hungry centralized hardware structures. Secondly, CMPs reduce costs by improving hardware resource utilization. On a multicore chip, co-scheduled threads can share costly microarchitecture resources that would otherwise be underutilized. Higher resource utilization improves aggregate performance and enables lower cost design alternatives.One of the resources that impacts most on the final performance of an application is the cache hierarchy. Caches store data recently used by the applications in order to take advantage of temporal and spatial locality of applications. Caches provide fast access to data, improving the performance of applications. Caches with low latencies have to be small, which prompts the design of a cache hierarchy organized into several levels of cache.In CMPs, the cache hierarchy is normally organized in a first level (L1) of instruction and data caches private to each core. A last level of cache (LLC) is normally shared among different cores in the processor (L2, L3 or both). Shared caches increase resource utilization and system performance. Large caches improve performance and efficiency by increasing the probability that each application can access data from a closer level of the cache hierarchy. It also allows an application to make use of the entire cache if needed.A second advantage of having a shared cache in a CMP design has to do with the cache coherency. In parallel applications, different threads share the same data and keep a local copy of this data in their cache. With multiple processors, it is possible for one processor to change the data, leaving another processor's cache with outdated data. Cache coherency protocol monitors changes to data and ensures that all processor caches have the most recent data. When the parallel application executes on the same physical chip, the cache coherency circuitry can operate at the speed of on-chip communications, rather than having to use the much slower between-chip communication, as is required with discrete processors on separate chips. These coherence protocols are simpler to design with a unified and shared level of cache onchip.Due to the advantages that multicore architectures offer, chip vendors use CMP architectures in current high performance, network, real-time and embedded systems. Several of these commercial processors have a level of the cache hierarchy shared by different cores. For example, the Sun UltraSPARC T2 has a 16-way 4MB L2 cache shared by 8 cores each one up to 8-way SMT. Other processors like the Intel Core 2 family also share up to a 12MB 24-way L2 cache. In contrast, the AMD K10 family has a private L2 cache per core and a shared L3 cache, with up to a 6MB 64-way L3 cache.As the long-term trend of increasing integration continues, the number of cores per chip is also projected to increase with each successive technology generation. Some significant studies have shown that processors with hundreds of cores per chip will appear in the market in the following years. The manycore era has already begun. Although this era provides many opportunities, it also presents many challenges. In particular, higher hardware resource sharing among concurrently executing threads can cause individual thread's performance to become unpredictable and might lead to violations of the individual applications' performance requirements. Current resource management mechanisms and policies are no longer adequate for future multicore systems.Some applications present low re-use of their data and pollute caches with data streams, such as multimedia, communications or streaming applications, or have many compulsory misses that cannot be solved by assigning more cache space to the application. Traditional eviction policies such as Least Recently Used (LRU), pseudo LRU or random are demand-driven, that is, they tend to give more space to the application that has more accesses to the cache hierarchy.When no direct control over shared resources is exercised (the last level cache in this case), it is possible that a particular thread allocates most of the shared resources, degrading other threads performance. As a consequence, high resource sharing and resource utilization can cause systems to become unstable and violate individual applications' requirements. If we want to provide a Quality of Service (QoS) to applications, we need to enhance the control over shared resources and enrich the collaboration between the OS and the architecture.In this thesis, we propose software and hardware mechanisms to improve cache sharing in CMP architectures. We make use of a holistic approach, coordinating targets of software and hardware to improve system aggregate performance and provide QoS to applications. We make use of explicit resource allocation techniques to control the shared cache in a CMP architecture, with resource allocation targets driven by hardware and software mechanisms.The main contributions of this thesis are the following:- We have characterized different single- and multithreaded applications and classified workloads with a systematic method to better understand and explain the cache sharing effects on a CMP architecture. We have made a special effort in studying previous cache partitioning techniques for CMP architectures, in order to acquire the insight to propose improved mechanisms.- In CMP architectures with out-of-order processors, cache misses can be served in parallel and share the miss penalty to access main memory. We take this fact into account to propose new cache partitioning algorithms guided by the memory-level parallelism (MLP) of each application. With these algorithms, the system performance is improved (in terms of throughput and fairness) without significantly increasing the hardware required by previous proposals.- Driving cache partition decisions with indirect indicators of performance such as misses, MLP or data re-use may lead to suboptimal cache partitions. Ideally, the appropriate metric to drive cache partitions should be the target metric to optimize, which is normally related to IPC. Thus, we have developed a hardware mechanism, OPACU, which is able to obtain at run-time accurate predictions of the performance of an application when running with different cache assignments.- Using performance predictions, we have introduced a new framework to manage shared caches in CMP architectures, FlexDCP, which allows the OS to optimize different IPC-related target metrics like throughput or fairness and provide QoS to applications. FlexDCP allows an enhanced coordination between the hardware and the software layers, which leads to improved system performance and flexibility.- Next, we have made use of performance estimations to reduce the load imbalance problem in parallel applications. We have built a run-time mechanism that detects parallel applications sensitive to cache allocation and, in these situations, the load imbalance is reduced by assigning more cache space to the slowest threads. This mechanism, helps reducing the long optimization time in terms of man-years of effort devoted to large-scale parallel applications.- Finally, we have stated the main characteristics that future multicore processors with thousands of cores should have. An enhanced coordination between the software and hardware layers has been proposed to better manage the shared resources in these architectures.

A novel radio resource management (RRM) scheme, which jointly considers the system characteristics from the physical, link and network layers, is proposed for cellular code division multiple access (CDMA) systems. Specifically, the power distribution at the physical layer distributes only the necessary amount of power to each connection in order to achieve its required signal-to-interference-plus-noise ratio (SINR). The rate allocation guarantees the required delay/jitter for real-time traffic and the minimum transmission rate requirement for non-real-time traffic. Efficient rate allocation is achieved by making use of the randomness and burstiness of the packet generation process. At the link layer, a packet scheduling scheme is developed based on the information of power distribution and rate allocation from the physical layer to achieve guaranteed quality of service (QoS). It schedules the system resource on a time slot basis to efficiently utilize the system resource in every time slot and to improve the packet throughput for non-real-time traffic. A connection admission control (CAC) scheme based on the lower layer resource allocation information is proposed at the network layer. The CAC scheme also makes use of user mobility information to reduce handoff connection dropping probability (HCDP). Theoretical analysis of the grade of service (GOS) performance, in terms of new connection blocking probability (NCBP), HCDP, and resource utilization, is given. Numerical results show that the proposed RRM scheme can achieve both effective QoS guarantee and efficient resource utilization.

An adaptive resource reservation and handoff priority scheme, which jointly considers the characteristics from the physical, link and network layers, is proposed for a packet switching Multicode (MC)-CDMA cellular network supporting multimedia applications. A call admission region is derived for call admission control (CAC) and handoff management with the satisfaction of quality of service (QoS) requirements for all kinds of multimedia traffic, where the QoS parameters include the wireless transmission bit error rate (BER), the packet loss rate (PLR) and delay requirement. The BER requirement is guaranteed by properly arranging simultaneous packet transmissions, whereas the PLR and delay requirements are guaranteed by the proposed packet scheduling and partial packet integration scheme. To give service priority to handoff calls, a threshold-based adaptive resource reservation scheme is proposed on the basis of a practical user mobility model and a proper handoff request prediction scheme. The resource reservation scheme gives handoff calls a higher admission priority over new calls, and is designed to adjust the reservation-request time threshold adaptively according to the varying traffic load. The individual reservation requests form a common reservation pool, and handoff calls are served on a first-come-first-serve basis. By exploiting the transmission rate adaptability of video calls to the available radio resources, the resources freed from rate-adaptive high-quality video calls by service degradation can be further used to prioritize handoff calls. With the proposed resource reservation and handoff priority scheme, the dynamic properties of the system can be closely captured and a better grade of service (GoS) in terms of new call blocking and handoff call dropping probabilities(rates) can be achieved compared to other schemes in literature. Numerical results are presented to show the improvement of the GoS performance and the efficient utilization of the radio resources.