Background: Funding practices in Ontario's acute care sector have undergone a substantive shift away from ‘lump-sum funding’ towards a combination of population-needs and performance-based financing (MOHLTC, 2013). In contrast very little is known about how funds are distributed across the province’s public health sector, specifically the 36 public health units (PHUs) that are mandated to deliver health promotion and disease prevention programs across Ontario. In fact the funding arrangement utilized by the public health sector has remained unchanged for several years, despite the growing burden of responsibilities on PHUs in terms of evolving population health needs and more expansive programmatic and performance expectations. Current literature on the processes, variables and overarching principles that govern the distribution of funds across PHUs remains considerably limited. Objectives: The objectives of this study were to develop a better understanding of how PHUs in Ontario are currently funded, and to examine what principles public health professionals believe should guide the distribution of resources across PHUs. The project sought to identify the fundamental principles that public health professionals believe should inform future thinking around public health funding. Methods: The perspectives of public health professionals who have proximal links to the current public health funding process served as the basis of the data discovery component for this study. A total of 14 in-depth interviews were conducted with a number of public health professionals to gather their insights on the current funding arrangement, and explore what principles they believe should be used to guide allocation decisions in the public health sector. Interviews were followed by a web survey to examine how public health professionals rank principles and perceive trade-offs between competing principles. Results: Public health professionals proposed a total of 12 principles to guide the distribution of resources across PHUs. These principles were grounded in three core social value judgments (need, equity, and transparency and accountability). The study provides important insights into the fundamental principles that public health professionals believe should guide allocation decisions and illustrates the complexity associated with distributing limited resources across health units, as well as possible directions for future research on this topic.

Tradicionalment, les tècniques d'accés múltiple en sistemes de comunicacions multi-usuari han estat desenvolupades o bé orientades a la connexió o bé orientades al tràfic. En el primer cas, l'objectiu és establir tants canals ortogonals com sigui possible per tal d'assignar-los als usuaris. Aquesta idea va motivar el disseny de les estratègies més conegudes, com són FDMA, TDMA i CDMA. Per altra banda, però, els mètodes d'accés aleatori que s'iniciaren amb el conegut ALOHA pretenen compartir estadísticament un mateix medi de comunicació aprofitant la necessitat de transmetre la informació a ràfegues que s'origina en les xarxes de dades. Així, molts dels actuals sistemes es poden encabir dins d'aquest esquema si a més a més, tenim en compte combinacions d'aquestes. No obstant, sistemes moderns com el DVB-RCS en l'entorn de comunicacions digitals per satèl·lit o el WiMAX en l'accés terrestre de banda ampla implementen mecanismes de petició i assignació de recursos, els quals requereixen una gestió dinàmica d'aquests en el sistema (és el que s'anomena distribució dinàmica de l'amplada de banda en un sentit ampli).L'anterior concepte inclou múltiples variables, configuracions i protocols tant de capa física com de capa d'enllaç. En aquesta tesi s'exploren en primer lloc les bases matemàtiques que permeten coordinar les diferents capes de la divisió OSI dels sistemes i els distints nodes dins la xarxa. Ens referim a les tècniques de descomposició focalitzades en problemes d'optimització convexa, els quals han aportat, durant els últims anys, solucions elegants a molts problemes dins dels camps del processament del senyal i les comunicacions. Revisarem els esquemes coneguts i proposarem una nova metodologia. Acte seguit, es comparen les diferents possibilitats de descomposició, cadascuna de les quals implica diferents maneres d'establir la senyalització. A la pràctica, són aquestes diverses opcions de descomposició les que infereixen les diferents interaccions entre capes o els protocols de control entre elements de la xarxa. Els resultats en quant a nombre d'iteracions requerides per a convergir a la solució òptima són favorables al nou mètode proposat, la qual cosa obra noves línies d'investigació.Finalment, es contribueix també amb dos exemples d'aplicació, en DVB-RCS i en WiMAX. Formulem el problema de gestió de recursos resultant de l'accés múltiple dissenyat per cadascun dels sistemes com un problema de maximització d'utilitat de xarxa (conegut com a NUM en la bibliografia) i el solucionarem aplicant les tècniques anteriors. L'objectiu serà garantir l'equitativitat entre els usuaris i preservar, al mateix temps, la seva qualitat de servei. Per aconseguir-ho, cal seleccionar funcions d'utilitat adequades que permetin balancejar l'assignació de recursos cap als serveis més prioritaris. Mostrarem que en els escenaris considerats, l'ús del mètode proposat comporta guanys significatius ja que requereix menys iteracions en el procés (i per tant, menys senyalització) o bé menys temps de càlcul en un enfoc centralitzat (que es tradueix en la possibilitat d'incloure més usuaris). També es mostren els avantatges de considerar interaccions entre capes, ja que es poden ajustar els paràmetres de capa física per tal d'afavorir els tràfics més prioritaris o bé extreure els requeriments de servei de valors típicament disponibles en capes superiors.En general, la implementació eficient de tècniques de gestió dinàmica de recursos treballant en l'accés múltiple dels sistemes pot aportar guanys significatius però implica establir una bona coordinació entre capes i elements de xarxa. L'eina matemàtica que ho possibilita són les tècniques de descomposició. Cada nou escenari i sistema introdueix un nou repte d'optimització i la capacitat que tinguem de coordinar totes les variables del sistema cap al punt òptim en determinarà el rendiment global. / Traditionally, multiple access schemes in multi-user communications systems have been designed either connection-oriented or traffic-oriented. In the first ones, the goal was to provide as many orthogonal channels as possible, each one serving a different connection. That is the motivation of the so-called FDMA, TDMA and CDMA solutions. On the other hand, random access techniques, which started with the so-called ALOHA protocol, aim to statistically multiplex a shared communication medium by means of exploiting the random and bursty nature of transmission needs in data networks. Most of the multiple access solutions can be interpreted according to that classification or as a combination of those approaches. Notwithstanding, modern systems, such as the digital satellite communications standard DVB-RCS or the broadband wireless access WiMAX, have implemented a multiple access technique where users request for transmission opportunities and receive grants from the network, therefore requiring dynamic bandwidth allocation techniques. The concept of dynamic bandwidth allocation is wide and involves a number of physical and link layer variables, configurations and protocols. In this Ph.D. dissertation we first explore the mathematical foundation that is required to coordinate the distinct layers of the OSI protocol stack and the distinct nodes within the network. We talk about decomposition techniques focused on the resolution of convex programs, which have elegantly solved many problems in the signal processing and communications fields during the last years. Known schemes are reviewed and a novel decomposition methodology is proposed. Thereafter, we compare the four resulting strategies, each one having its own particular signalling needs, which results in distinct cross-layer interactions or signalling protocols at implementation level. The results in terms of iterations required to converge are favourable to the proposed method, thus opening a new line of research.Finally, we contribute with two practical application examples in the DVB-RCS and WiMAX systems. First, we formulate the dynamic bandwidth allocation problem that is derived from the multiple access schemes of both systems. Thereafter, the resulting Network Utility Maximization (NUM) based problem is solved by means of the previous decomposition mechanisms. The goal is to guarantee fairness among the users at the same time that Quality of Service (QoS) is preserved. In order to achieve that, we choose adequate utility functions that allow to balance the allocation towards the most priority traffic flows under a common fairness framework. We show that in the scenarios considered, the novel proposed coupled-decomposition method reports significant gains since it reduces significantly the iterations required (less iterations implies less signalling) or it reduces the time needed to obtain the optimal allocation when it is centrally computed (more users can be managed). We further show the advantages of cross-layer interactions with the physical and upper layers, which allow to benefit from more favourable adjustments of the transmission parameters and to consider the QoS requirements at upper layers. In general, an efficient implementation of dynamic bandwidth allocation techniques in Demand Assignment Multiple Access (DAMA) schemes may report significant performance gains but it requires proper coordination among system layers and network nodes, which is attained thanks to decomposition techniques. Each new scenario and system adds another optimization challenge and, as far as we are able to coordinate all the variables in the system towards that optimal point, the highest will be the revenue.

This thesis contributes toward the design of a quality-of-service (QoS) aware network layer for wireless ad hoc networks. With the lack of an infrastructure in ad hoc networks, the role of the network layer is not only to perform multihop routing between a source node and a destination node, but also to establish an end-to-end connection between communicating peers that satisfies the service level requirements of multimedia applications running on those peers. Wireless ad hoc networks represent autonomous distributed systems that are infrastructure-less, fully distributed, and multi-hop in nature. Over the last few years, wireless ad hoc networks have attracted significant attention from researchers. This has been fueled by recent technological advances in the development of multifunction and low-cost wireless communication gadgets. Wireless ad hoc networks have diverse applications spanning several domains, including military, commercial, medical, and home networks. Projections indicate that these self-organizing wireless ad hoc networks will eventually become the dominant form of the architecture of telecommunications networks in the near future. Recently, due to increasing popularity of multimedia applications, QoS support in wireless ad hoc networks has become an important yet challenging objective. The challenge lies in the need to support the heterogeneous QoS requirements (e.g., data rate, packet loss probability, and delay constraints) for multimedia applications and, at the same time, to achieve efficient radio resource utilization, taking into account user mobility and dynamics of multimedia traffic. In terms of research contributions, we first present a position-based QoS routing framework for wireless ad-hoc networks. The scheme provides QoS guarantee in terms of packet loss ratio and average end-to-end delay (or throughput) to ad hoc networks loaded with constant rate traffic. Via cross-layer design, we apply call admission control and temporary bandwidth reservation on discovered routes, taking into consideration the physical layer multi-rate capability and the medium access control (MAC) interactions such as simultaneous transmission and self interference from route members. Next, we address the network-layer resource allocation where a single-hop ad hoc network is loaded with random traffic. As a starting point, we study the behavior of the service process of the widely deployed IEEE 802.11 DCF MAC when the network is under different traffic load conditions. Our study investigates the near-memoryless behavior of the service time for IEEE 802.11 saturated single-hop ad hoc networks. We show that the number of packets successfully transmitted by any node over a time interval follows a general distribution, which is close to a Poisson distribution with an upper bounded distribution distance. We also show that the service time distribution can be approximated by the geometric distribution and illustrate that a simplified queuing system can be used efficiently as a resource allocation tool for single hop IEEE 802.11 ad hoc networks near saturation. After that, we shift our focus to providing probabilistic packet delay guarantee to multimedia users in non-saturated IEEE 802.11 single hop ad hoc networks. We propose a novel stochastic link-layer channel model to characterize the variations of the IEEE 802.11 channel service process. We use the model to calculate the effective capacity of the IEEE 802.11 channel. The channel effective capacity concept is the dual of the effective bandwidth theory. Our approach offers a tool for distributed statistical resource allocation in single hop ad hoc networks, which combines both efficient resource utilization and QoS provisioning to a certain probabilistic limit. Finally, we propose a statistical QoS routing scheme for multihop IEEE 802.11 ad hoc networks. Unlike most of QoS routing schemes in literature, the proposed scheme provides stochastic end-to-end delay guarantee, instead of average delay guarantee, to delay-sensitive bursty traffic sources. Via a cross-layer design approach, the scheme selects the routes based on a geographical on-demand ad hoc routing protocol and checks the availability of network resources by using traffic source and link-layer channel models, incorporating the IEEE 802.11 characteristics and interaction. Our scheme extends the well developed effective bandwidth theory and its dual effective capacity concept to multihop IEEE 802.11 ad hoc networks in order to achieve an efficient utilization of the shared radio channel while satisfying the end-to-end delay bound.

Due to the existence of multiple stakeholders with conflicting goals and policies, alterations to the existing Internet architecture are now limited to simple incremental updates; deployment of any new, radically different technology is next to impossible. To fend off this ossification, network virtualization has been propounded as a diversifying attribute of the future inter-networking paradigm. In this talk, we provide an overview of the network virtualization environment (NVE) and address two basic problems in this emerging field of networking research. The identity management problem is primarily concerned with ensuring interoperability across heterogeneous identifier spaces for locating and identifying end hosts in different virtual networks. We describe the architectural and the functional components of a novel identity management framework (iMark) that enables end-to-end connectivity across heterogeneous virtual networks in the NVE without revoking their autonomy. The virtual network embedding problem deals with the mapping of virtual nodes and links onto physical network resources. We argue that the separation of the node mapping and the link mapping phases in the existing algorithms considerably reduces the solution space and degrades embedding quality. We propose coordinated node and link mapping to devise two algorithms (D-ViNE and R-ViNE) for the online version of the problem under realistic assumptions and compare their performance with the existing heuristics.

The high deployment and maintenance costs of last mile wireline networks (i.e., DSL and cable networks) have urged service providers to search for new cost-effective solutions to provide broadband connectivity. Broadband wireless access (BWA) networks, which offer a wide coverage area and high transmission rates in addition to their fast and low-cost deployment, have emerged as an alternative to last mile wireline networks. Therefore, BWA networks are expected to be deployed in areas with different terrain profiles (e.g., urban, suburban, rural) where wireless communication faces different channel impairments. This fact necessitates the adoption of various transmission technologies that combat the channel impairments of each profile. Implementation scenarios of BWA networks considered in this thesis are multicarrier-based direct transmission and single carrier-based cooperative transmission scenarios. The performance of these transmission technologies highly depends on how resources are allocated. In this thesis, we focus on the development of practical resource allocation schemes for the mentioned BWA networks implementation scenarios. In order to develop practical schemes, the imperfection of channel state information (CSI) and computational power limitations are among considered practical implementation issues. The design of efficient resource allocation schemes at the MAC layer heavily relies on the CSI reported from the PHY layer as a measure of the wireless channel condition. The channel estimation error and feedback delay renders the reported CSI erroneous. The inaccuracy in CSI propagates to higher layers, resulting in performance degradation. Although this effect is intuitive, a quantitative measure of this degradation is necessary for the design of practical resource allocation schemes. An approach to the evaluation of the ergodic mutual information that reflects this degradation is developed for single carrier, multicarrier, direct, and cooperative scenarios with inaccurate CSI. Given the CSI estimates and estimation error statistics, the presented evaluation of ergodic mutual information can be used in resource allocation and in assessing the severity of estimation error on performance degradation. A point-to-multipoint (PMP) network that employs orthogonal frequency division multiple access (OFDMA) is considered as one of the most common implementation scenarios of BWA networks. Replacing wireline networks requires not only providing the last mile connectivity to subscribers but also supporting their diverse services with stringent quality of service (QoS) requirements. Therefore, the resource allocation problem (i.e., subcarriers, rate and power allocation) is modeled as a network utility maximization (NUM) one that captures the characteristics of this implementation scenario. A dual decomposition-based resource allocation scheme that takes into consideration the diversity of service requirements and inaccuracy of the CSI estimation is developed. Numerical evaluations and simulations are conducted to validate our theoretical claims that the scheme maximizes resource utilization, coordinates with the call admission controller to guarantee QoS, and accounts for CSI inaccuracy. Cooperation has recently received great attention from the research community and industry because of its low cost and fast deployment in addition to the performance improvement it brings to BWA networks. In cooperative scenarios, subscribers cooperate to relay each other's signals. For this implementation scenario of BWA networks, a robust and constrained Kalman filter-based power allocation scheme is proposed to minimize power consumption and guarantee bit error probability (BEP) requirements. The proposed scheme is robust to CSI inaccuracy, responsive to changes in BEP requirements, and optimal in allocating resources. In summary, research results presented in this thesis contribute to the development of practical resource allocation schemes for BWA networks.

Wireless Mesh Networks (WMNs) built with commodity 802.11 radios are a cost-effective means of providing last mile broadband Internet access. Their multihop architecture allows for rapid deployment and organic growth of these networks. 802.11 radios are an important building block in WMNs. These low cost radios are readily available, and can be used globally in license-exempt frequency bands. However, the 802.11 Distributed Coordination Function (DCF) medium access mechanism does not scale well in large multihop networks. This produces suboptimal behavior in many transport protocols, including TCP, the dominant transport protocol in the Internet. In particular, cross-layer interaction between DCF and TCP results in flow level unfairness, including starvation, with backlogged traffic sources. Solutions found in the literature propose distributed source rate control algorithms to alleviate this problem. However, this requires MAC-layer or transport-layer changes on all mesh routers. This is often infeasible in practical deployments. In wireline networks, router-assisted rate control techniques have been proposed for use alongside end-to-end mechanisms. We evaluate the feasibility of establishing similar centralized control via gateway mesh routers in WMNs. We find that commonly used router-assisted flow control schemes designed for wired networks fail in WMNs. This is because they assume that: (1) links can be scheduled independently, and (2) router queue buildups are sufficient for detecting congestion. These abstractions do not hold in a wireless network, rendering wired scheduling algorithms such as Fair Queueing (and its variants) and Active Queue Management (AQM) techniques ineffective as a gateway-enforceable solution in a WMN. We show that only non-work-conserving rate-based scheduling can effectively enforce rate allocation via a single centralized traffic-aggregation point. In this context we propose, design, and evaluate a framework of centralized, measurement-based, feedback-driven mechanisms that can enforce a rate allocation policy objective for adaptive traffic streams in a WMN. In this dissertation we focus on fair rate allocation requirements. Our approach does not require any changes to individual mesh routers. Further, it uses existing data traffic as capacity probes, thus incurring a zero control traffic overhead. We propose two mechanisms based on this approach: aggregate rate control (ARC) and per-flow rate control (PFRC). ARC limits the aggregate capacity of a network to the sum of fair rates for a given set of flows. We show that the resulting rate allocation achieved by DCF is approximately max-min fair. PFRC allows us to exercise finer-grained control over the rate allocation process. We show how it can be used to achieve weighted flow rate fairness. We evaluate the performance of these mechanisms using simulations as well as implementation on a multihop wireless testbed. Our comparative analysis show that our mechanisms improve fairness indices by a factor of 2 to 3 when compared with networks without any rate limiting, and are approximately equivalent to results achieved with distributed source rate limiting mechanisms that require software modifications on all mesh routers.

The use of relays is seen as a promising way to extend cell coverage and increase rates in LTE Advanced networks. Instead of increasing the number of base stations (BS), relays with lower cost could provide similar gains. A relay will have a wireless link to the closest BS as only connection to the core network and will cover areas close to the cell edge or other areas with limited rates. Performing transmissions in several hops (BS-relay & relay-user) requires more radio resources than using direct transmission. This thesis studies how the available radio resources should be allocated between relays and users in order to maximize throughput and/or fairness. Time and frequency multiplexed backhaul is investigated under a full buffer traffic assumption. It is shown that the system will be backhaul limited and that the two ways of multiplexing will perform equally when maximising throughput and/or fairness. The analysis results in a set of throughput/fairness suboptimal solutions, dependant on how many relays are used per cell. The results are verified by simulations, which also show the limiting effects on throughput caused by interference between relays. It is also analysed how the resource allocation should be done given non-fullbuffer traffic. A resource allocation that minimises packet delay given a certain number of relays per cell is presented. The analysis is based on queuing theory. Finally some different schedulers and their suitability for relay networks are discussed. Simulation results are shown, comparing the throughput and fairness of Round Robin, Weighted Round Robin, Proportional Fairness and Weighted Proportional Fairness schemes. It is shown that allocating the resource among the relays according to the number of users served by the relays improves the fairness.

The new mobile standard Long Term Evolution delivers high data rates, small delay and a more efficiently utilized RF spectrum. A solution to maintain this performance in user dense areas or areas with bad reception is the deployment of so-called femtocells. Femtocells are small base stations that are deployed indoors and share the RF spectrum with the whole mobile network. The idea is that femtocells will increase mobile operators network coverage and capacity while it at the same time increase users data throughput. There are several challenges with femtocells, both technical and economical ones. The most debated issues is how femtocells should schedule users while operating in an environment where other femtocells and base stations are interfering. In this work we developed a simulation tool to simulate the scheduling interaction between femtocells and base stationsin order to show the performance of radio resource schedulers. This rapport also aims to evaluate an approach to a femtocell scheduler to solve this issue in a satisfying way. The report gives a description of the structure of the implemented simulation tool together with some reflections on how future designs of similar or more complex simulation environments could be done.

The goal of this Master's thesis was to solve resource allocation problems in wireless networks through the implementation of a lightweight simulation platform. The spectrum and power resources of wireless networks have to be efficiently used to accommodate the growing number of wireless terminals and the massive increase of data transferred by their applications. The major problem that needs to be tackled is interference, which significantly limits the performance of wireless systems. In this thesis, the resource allocation of interest was the joint problem of scheduling and power control with Quality of Service (QoS) constraints. The Signal-to-Interference-plus-Noise Ratio (SINR) was used to quantify QoS. This thesis studied the recently proposed mixed-integer linear programming (MILP) formulation of the problem. Due to the scheduling component, the problem is inherently combinatorial and NP-hard, therefore computationally expensive and difficult to solve in tractable time. A simulation platform was implemented in order to automate and facilitate the solving process.As a starting point, wireless channels and channel modeling issues were studied. Then, the platform was implemented to simulate random instances of multi-cellular wireless networks, with several mobile stations per cell, and generate the corresponding channels. Finally, the platform was extended to use the GNU Linear Programming Kit (GLPK) API in order to optimally solve the aforementioned formulated problem for various inputs of generated channels.Tests of the simulation platform were performed to check the consistency of the results. Indeed, the output results satisfied the initial expectations regarding the SINR constraints and the formulation. Moreover, they were produced in reasonable time. An analysis of the output results was presented.This thesis resulted in a configurable and lightweight simulation platform which is able to solve the MILP-formulated resource allocation problem. The simulation platform is basic and does not cover all the aspects of multi-cellular wireless networks and wireless channels. Due to its modularity, it can be extended in a future project.

This thesis contributes toward the design of a quality-of-service (QoS) aware network layer for wireless ad hoc networks. With the lack of an infrastructure in ad hoc networks, the role of the network layer is not only to perform multihop routing between a source node and a destination node, but also to establish an end-to-end connection between communicating peers that satisfies the service level requirements of multimedia applications running on those peers. Wireless ad hoc networks represent autonomous distributed systems that are infrastructure-less, fully distributed, and multi-hop in nature. Over the last few years, wireless ad hoc networks have attracted significant attention from researchers. This has been fueled by recent technological advances in the development of multifunction and low-cost wireless communication gadgets. Wireless ad hoc networks have diverse applications spanning several domains, including military, commercial, medical, and home networks. Projections indicate that these self-organizing wireless ad hoc networks will eventually become the dominant form of the architecture of telecommunications networks in the near future. Recently, due to increasing popularity of multimedia applications, QoS support in wireless ad hoc networks has become an important yet challenging objective. The challenge lies in the need to support the heterogeneous QoS requirements (e.g., data rate, packet loss probability, and delay constraints) for multimedia applications and, at the same time, to achieve efficient radio resource utilization, taking into account user mobility and dynamics of multimedia traffic. In terms of research contributions, we first present a position-based QoS routing framework for wireless ad-hoc networks. The scheme provides QoS guarantee in terms of packet loss ratio and average end-to-end delay (or throughput) to ad hoc networks loaded with constant rate traffic. Via cross-layer design, we apply call admission control and temporary bandwidth reservation on discovered routes, taking into consideration the physical layer multi-rate capability and the medium access control (MAC) interactions such as simultaneous transmission and self interference from route members. Next, we address the network-layer resource allocation where a single-hop ad hoc network is loaded with random traffic. As a starting point, we study the behavior of the service process of the widely deployed IEEE 802.11 DCF MAC when the network is under different traffic load conditions. Our study investigates the near-memoryless behavior of the service time for IEEE 802.11 saturated single-hop ad hoc networks. We show that the number of packets successfully transmitted by any node over a time interval follows a general distribution, which is close to a Poisson distribution with an upper bounded distribution distance. We also show that the service time distribution can be approximated by the geometric distribution and illustrate that a simplified queuing system can be used efficiently as a resource allocation tool for single hop IEEE 802.11 ad hoc networks near saturation. After that, we shift our focus to providing probabilistic packet delay guarantee to multimedia users in non-saturated IEEE 802.11 single hop ad hoc networks. We propose a novel stochastic link-layer channel model to characterize the variations of the IEEE 802.11 channel service process. We use the model to calculate the effective capacity of the IEEE 802.11 channel. The channel effective capacity concept is the dual of the effective bandwidth theory. Our approach offers a tool for distributed statistical resource allocation in single hop ad hoc networks, which combines both efficient resource utilization and QoS provisioning to a certain probabilistic limit. Finally, we propose a statistical QoS routing scheme for multihop IEEE 802.11 ad hoc networks. Unlike most of QoS routing schemes in literature, the proposed scheme provides stochastic end-to-end delay guarantee, instead of average delay guarantee, to delay-sensitive bursty traffic sources. Via a cross-layer design approach, the scheme selects the routes based on a geographical on-demand ad hoc routing protocol and checks the availability of network resources by using traffic source and link-layer channel models, incorporating the IEEE 802.11 characteristics and interaction. Our scheme extends the well developed effective bandwidth theory and its dual effective capacity concept to multihop IEEE 802.11 ad hoc networks in order to achieve an efficient utilization of the shared radio channel while satisfying the end-to-end delay bound.