Broadband speeds, Internet literacy and digital technologies have been steadily evolving over the last decade. Broadband infrastructure has become a key asset in today’s society, enabling innovation, driving economic efficiency and stimulating cultural inclusion. However, populations living in remote and rural communities are unable to take advantage of these trends. Globally, a significant part of the world population is still deprived of basic access to the Internet. Broadband Wireless Access (BWA) networks are regarded as a viable solution for providing Internet access to populations living in rural regions. In recent years, Wireless Internet Service Providers (WISPs) and community organizations around the world proved that rural BWA networks can be an effective strategy and a profitable business. This research began by deploying a BWA network testbed, which also provides Internet access to several remote communities in the harsh environment of the Scottish Highlands and Islands. The experience of deploying and operating this network pointed out three unresolved research challenges that need to be addressed to ease the path towards widespread deployment of rural BWA networks, thereby bridging the rural-urban broadband divide. Below, our research contributions are outlined with respect to these challenges. Firstly, an effective planning paradigm for deploying BWA networks is proposed: incremental planning. Incremental planning allows to anticipate return of investment and to overcome the limited network infrastructure (e.g., backhaul fibre links) in rural areas. I have developed a software tool called IncrEase and underlying network planning algorithms to consider a varied set of operational metrics to guide the operator in identifying the regions that would benefit the most from a network upgrade, automatically suggesting the best long-term strategy to the network administrator. Second, we recognize that rural and community networks present additional issues for network management. As the Internet uplink is often the most expensive part of the operational expenses for such deployments, it is desirable to minimize overhead for network management. Also, unreliable connectivity between the network operation centre and the network being managed can render traditional centralized management approaches ineffective. Finally, the number of skilled personnel available to maintain such networks is limited. I have developed a distributed network management platform called Stix for BWA networks, to make it easy to manage such networks for rural/community deployments and WISPs alike while keeping the network management infrastructure scalable and flexible. Our approach is based on the notions of goal-oriented and in-network management: administrators graphically specify network management activities as workflows, which are run in the network on a distributed set of agents that cooperate in executing those workflows and storing management information. The Stix system was implemented on low-cost and small form-factor embedded boards and shown to have a low memory footprint. Third, the research focus moves to the problem of assessing broadband coverage and quality in a given geographic region. The outcome is BSense, a flexible framework that combines data provided by ISPs with measurements gathered by distributed software agents. The result is a census (presented as maps and tables) of the coverage and quality of broadband connections available in the region of interest. Such information can be exploited by ISPs to drive their growth, and by regulators and policy makers to get the true picture of broadband availability in the region and make informed decisions. In exchange for installing the multi-platform measurement software (that runs in the background) on their computers, users can get statistics about their Internet connection and those in their neighbourhood. Finally, the lessons learned through this research are summarised. The outcome is a set of suggestions about how the deployment and operation of rural BWA networks, including our own testbed, can be made more efficient by using the proper tools. The software systems presented in this thesis have been evaluated in lab settings and in real networks, and are available as open-source software.

This thesis presents several simple, robust, and optimal resource management schemes for multihop wireless access networks with the main focus on multi-channel wireless mesh networks (MC WMNs). In this regard, various resource management optimization problems are formulated arid efficient algorithms are proposed to solve each problem. First, we consider the channel as signment problem in MC-WMNs and formulate different resource management problems within the general framework of network utility maximization (NUM). Unlike most of the previously proposed channel assignment schemes, our algorithms can not only assign the orthogonal (i.e., non-overlapped) channels, but also partially overlapped channels. This better utilizes the avail able frequency spectrum as a critical resource in MC-WMNs. Second, we propose two distributed random medium access control (MAC) algorithms to solve a non-convex NUM problem at the MAC layer. The first algorithm is fast, optimal, and robust to message loss and delay. It also only requires a limited message passing among the wireless nodes. Using distributed learning techniques, we then propose another NUM-based MAC algorithm which achieves the optimal performance without frequent message exchange. Third, based on our results on random MAC, we develop a distributed multi-interface multi-channel random access algorithm to solve the NUM problem in MC-WMNs. Different from most of the previous channel assignment schemes in the literature, where channel assignment is intuitively modeled in the form of combinatorial and discrete optimization problems, our scheme is based on formulating a novel continuous optimization model. This makes the analysis and implementation significantly easier. Finally, we consider the problem of pricing and monetary exchange in multi-hop wireless access networks, where each intermediate node receives a payment to compensate for its offered packet forwarding service. In this regard, we propose a market-based wireless access network model with two-fold pricing. It uses relay-pricing to encourage collaboration among the access points. It also uses interference pricing to leverage optimal resource management. In general, this thesis widely benefits from several mathematical techniques as both modeling and solution tools to achieve simple, robust, optimal, and practical resource management strategies for future wireless access networks.

This thesis presents several simple, robust, and optimal resource management schemes for multihop wireless access networks with the main focus on multi-channel wireless mesh networks (MC WMNs). In this regard, various resource management optimization problems are formulated arid efficient algorithms are proposed to solve each problem. First, we consider the channel as signment problem in MC-WMNs and formulate different resource management problems within the general framework of network utility maximization (NUM). Unlike most of the previously proposed channel assignment schemes, our algorithms can not only assign the orthogonal (i.e., non-overlapped) channels, but also partially overlapped channels. This better utilizes the avail able frequency spectrum as a critical resource in MC-WMNs. Second, we propose two distributed random medium access control (MAC) algorithms to solve a non-convex NUM problem at the MAC layer. The first algorithm is fast, optimal, and robust to message loss and delay. It also only requires a limited message passing among the wireless nodes. Using distributed learning techniques, we then propose another NUM-based MAC algorithm which achieves the optimal performance without frequent message exchange. Third, based on our results on random MAC, we develop a distributed multi-interface multi-channel random access algorithm to solve the NUM problem in MC-WMNs. Different from most of the previous channel assignment schemes in the literature, where channel assignment is intuitively modeled in the form of combinatorial and discrete optimization problems, our scheme is based on formulating a novel continuous optimization model. This makes the analysis and implementation significantly easier. Finally, we consider the problem of pricing and monetary exchange in multi-hop wireless access networks, where each intermediate node receives a payment to compensate for its offered packet forwarding service. In this regard, we propose a market-based wireless access network model with two-fold pricing. It uses relay-pricing to encourage collaboration among the access points. It also uses interference pricing to leverage optimal resource management. In general, this thesis widely benefits from several mathematical techniques as both modeling and solution tools to achieve simple, robust, optimal, and practical resource management strategies for future wireless access networks.

Broadband Wireless Access Systems (BWASs) such as High Speed Downlink Packet Access (HSDPA) and the Worldwide Interoperability for Microwave Access (WiMAX), pose a myriad of new opportunities for leveraging the support of a wide range of “content-rich” mobile multimedia services with diverse Quality of Service (QoS) requirements. This is due to the remarkably high bandwidth that is supported by these systems, which was previously only available to wireline connections. Despite the support for such high bandwidth, satisfying the diverse QoS of users while maximizing the revenues of network operators is still one of the major issues in these systems. Bandwidth management, therefore, will play a decisive role in the success of such wireless access systems. Without efficient bandwidth management, network operators may not be able to meet the growing demand of users for multimedia services, and may consequently suffer great revenue loss. Bandwidth management in BWASs is, however, a challenging problem due to many issues that need to be taken into consideration. Examples of such issues include the diverse QoS requirements of the services that BWASs support, the varying channel quality conditions of mobile users, and hence the varying amount of resources that are needed to guarantee certain QoS levels during the lifetime of user connections, the utilization of shared channels for data delivery instead of dedicated ones and network congestion. In this thesis, we address the problem of bandwidth management in BWASs and propose efficient economic-based solutions in order to deal with these issues at different bandwidth management levels, and hence enhance the QoS support in these systems. Specifically, we propose a bandwidth management framework for BWASs. The framework is designed to support multiple classes of traffic with different users having different QoS requirements, maximize the throughput of BWASs, support inter- and intra-class fairness, prevent network congestion and maximize the network operator’s revenues. The framework consists of three related components, namely packet scheduling, bandwidth provisioning and Call Admission Control-based dynamic pricing. By efficiently managing the wireless bandwidth prior to users’ admission (i.e.,pre-admission bandwidth management) and during the users’ connections (i.e., post-admission bandwidth management), these schemes are shown to achieve the design goals of our framework. / Thesis (Ph.D, Computing) -- Queen's University, 2009-04-01 15:35:36.213

This thesis presents several simple, robust, and optimal resource management schemes for multihop wireless access networks with the main focus on multi-channel wireless mesh networks (MC WMNs). In this regard, various resource management optimization problems are formulated arid efficient algorithms are proposed to solve each problem. First, we consider the channel as signment problem in MC-WMNs and formulate different resource management problems within the general framework of network utility maximization (NUM). Unlike most of the previously proposed channel assignment schemes, our algorithms can not only assign the orthogonal (i.e., non-overlapped) channels, but also partially overlapped channels. This better utilizes the avail able frequency spectrum as a critical resource in MC-WMNs. Second, we propose two distributed random medium access control (MAC) algorithms to solve a non-convex NUM problem at the MAC layer. The first algorithm is fast, optimal, and robust to message loss and delay. It also only requires a limited message passing among the wireless nodes. Using distributed learning techniques, we then propose another NUM-based MAC algorithm which achieves the optimal performance without frequent message exchange. Third, based on our results on random MAC, we develop a distributed multi-interface multi-channel random access algorithm to solve the NUM problem in MC-WMNs. Different from most of the previous channel assignment schemes in the literature, where channel assignment is intuitively modeled in the form of combinatorial and discrete optimization problems, our scheme is based on formulating a novel continuous optimization model. This makes the analysis and implementation significantly easier. Finally, we consider the problem of pricing and monetary exchange in multi-hop wireless access networks, where each intermediate node receives a payment to compensate for its offered packet forwarding service. In this regard, we propose a market-based wireless access network model with two-fold pricing. It uses relay-pricing to encourage collaboration among the access points. It also uses interference pricing to leverage optimal resource management. In general, this thesis widely benefits from several mathematical techniques as both modeling and solution tools to achieve simple, robust, optimal, and practical resource management strategies for future wireless access networks. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Digital technology, network compression technology and Internet technology universal utilization, causes the communication market inherent in the increasingly blurred boundaries and a convergence of the phenomenon. Under this background, the industry unceasingly promotes the service more and more, or provides triple play (voice, data and video service) to change the industrial competition situation. This research union "Grounded Theory" and "Importance-Performance Analysis " to Taiwan's telecommunications market to explore the theme through telecommunications technology and innovation as the main shaft, supported by the world's major countries in Europe, the United States and Japan's market performance. An analysis of the trends of digital convergence, policies and the evolution of the telecommunications industry. The research results are as follows: 1. The government unit: Will grasp the future industry tendency to develop the appropriate regulation system from the recent communication industrial structure by the industrial change. 2. The communications industry: To develop digital convergence in the competition strategy by factors on telecommunication environment, market analysis, technical development situation and government policy.

Wireless access networks today consume 0.5 percent of the global energy. Rapidly growing demand for capacity will further increase the energy consumption. Thus, improving energy efficiency has a great importance not only for environmental awareness but also to lower the operational cost of network operators. However, current networks which are optimized based on non-energy related objectives introduce challenges towards green wireless access networks. In this thesis we investigate the solutions at the deployment level and handle energy efficiency assessment issues in wireless access networks. The precise characterization of the power consumption of the whole network has a crucial importance in order to obtain consistent conclusions from any proposed solution at the network level. For this purpose, we propose a novel power consumption model  considering  the impact of backhaul for two established technologies, i.e., fiber and microwave, which is often ignored in the literature. We show that there is a tradeoff between the power saved by using low power base stations and the excess power that has to be spent for backhauling their traffic which therefore needs to carefully be included into energy efficiency analysis. Furthermore, among the solutions that are analyzed, fiber-based backhaul solution is identified to outperform microwave regardless of the considered topology. The proposed model is then used to gain a general insight regarding the important design parameters and their possible impact on energy- and cost oriented network design. To this end, we present a  high-level framework to see the main tradeoffs between energy, infrastructure cost, spectrum and show that future high-capacity systems are increasingly limited by infrastructure and energy costs where spectrum has a strong positive impact on both. We then investigate different network deployment strategies to improve the energy efficiency where we focus on the impact of various base station types, cell size, power consumption parameters and the capacity demand. We propose a refined power consumption model where the parameters are determined in accordance with cell size. We show that network densification can only be justified when capacity expansion is anticipated and over-provisioning of the network is not plausible for greener network. The improvement through heterogeneous networks is indicated to be highly related to the traffic demand where up to 30% improvement is feasible for high area throughput targets. Furthermore, we consider the problem of energy efficiency assessment at the network level in order to allow operators to know their current status and quantify the potential energy savings of different solutions to establish future strategies. We propose elaborate metric forms that can characterize the efficiency and a methodology that indicate how to perform a reliable and accurate measurement considering the complexity of wireless networks. We show the weakness of the current metrics reporting the "effectiveness" and how these might indicate disputable improvement directions unless they are properly revised. This illustrates the need for a standardized network level energy efficiency evaluation methodology towards green wireless access. / <p>QC 20121109</p> / Energy-efficient wireless networking (eWIN)

To support wireless-oriented services, a new generation of Web services called Mobile services (M-services) has emerged. M-services provide mobile users access to services through wireless networks. One of the important issues in M-service environment is how to discover and access M-services efficiently. In this dissertation, we propose time and power efficient access methods for M-services. We focus on methods for accessing broadcast based M-services from multiple wireless channels. We first discuss efficient access methods in data-oriented wireless broadcast systems. We then discuss how to extend current wireless broadcast systems to support simple M-services. We present a novel infrastructure that provides a multi-channel broadcast framework for mobile users to effectively discover and access composite M-services. Multi-channel algorithms are proposed for efficiently accessing composite services. We define a few semantics that have impact on access efficiency in the proposed infrastructure. We discuss semantic access to composite services. Broadcast channel organizations suitable for discovering and accessing composite services are proposed. We also derive analytical models for these channel organizations. To provide practical study for the proposed infrastructure and access methods, a testbed is developed for simulating accessing M-services in a broadcast-based environment. Extensive experiments have been conducted to study the proposed access methods and broadcast channel organizations. The experimental results are presented and discussed. / Ph. D.

With the exploding increase of mobile users and the release of new wireless applications, the high bandwidth requirement has been taking as a main concern for the design and development of the wireless techniques. There is no doubt that broadband wireless access with the support of heterogeneous kinds of applications is the trend in the next generation wireless networks. As a promising broadband wireless access standard, IEEE 802.16 has attracted extensive attentions from both industry and academia due to its high data rate and the inherent media access control (MAC) mechanism, which takes the service differentiation and quality of service (QoS) provisioning into account. To achieve service differentiation and QoS satisfaction for heterogenous applications is a very complicated issue. It refers to many fields, such as connection admission control (CAC), congestion control, routing algorithm, MAC protocol, and scheduling scheme. Among these fields, packet scheduling plays one of the most important roles in fulfilling service differentiation and QoS provisioning. It decides the order of packet transmissions, and provides mechanisms for the resource allocation and multiplexing at the packet level to ensure that different types of applications meet their service requirements and the network maintains a high resource utilization. In this thesis, we focus on the packet scheduling for difficult types of services in IEEE 802.16 networks, where unicast and mulitcast scheduling are investigated. For unicast scheduling, two types of services are considered: non-real-time polling service (nrtPS) and best effort (BE) service. We propose a flexible and efficient resource allocation and scheduling framework for nrtPS applications to achieve a tradeoff between the delivery delay and resource utilization, where automatic repeat request (ARQ) mechanisms and the adaptive modulation and coding (AMC) technique are jointly considered. For BE service, considering the heterogeneity of subscriber stations (SSs) in IEEE 802.16 networks, we propose the weighted proportional fairness scheduling scheme to achieve the flexible scheduling and resource allocation among SSs based on their traffic demands/patterns. For multicast scheduling, a cooperative multicast scheduling is proposed to achieve high throughput and reliable transmission. By using the two-phase transmission model to exploit the spatial diversity gain in the multicast scenario, the proposed scheduling scheme can significantly improve the throughput not only for all multicast groups, but also for each group member. Analytical models are developed to investigate the performance of the proposed schemes in terms of some important performance measurements, such as throughput, resource utilization, and service probability. Extensive simulations are conducted to illustrate the efficient of the proposed schemes and the accuracy of the analytical models. The research work should provide meaningful guidelines for the system design and the selection of operational parameters, such as the number of TV channels supported by the network, the achieved video quality of each SS in the network, and the setting of weights for SSs under different BE traffic demands.

With the exploding increase of mobile users and the release of new wireless applications, the high bandwidth requirement has been taking as a main concern for the design and development of the wireless techniques. There is no doubt that broadband wireless access with the support of heterogeneous kinds of applications is the trend in the next generation wireless networks. As a promising broadband wireless access standard, IEEE 802.16 has attracted extensive attentions from both industry and academia due to its high data rate and the inherent media access control (MAC) mechanism, which takes the service differentiation and quality of service (QoS) provisioning into account. To achieve service differentiation and QoS satisfaction for heterogenous applications is a very complicated issue. It refers to many fields, such as connection admission control (CAC), congestion control, routing algorithm, MAC protocol, and scheduling scheme. Among these fields, packet scheduling plays one of the most important roles in fulfilling service differentiation and QoS provisioning. It decides the order of packet transmissions, and provides mechanisms for the resource allocation and multiplexing at the packet level to ensure that different types of applications meet their service requirements and the network maintains a high resource utilization. In this thesis, we focus on the packet scheduling for difficult types of services in IEEE 802.16 networks, where unicast and mulitcast scheduling are investigated. For unicast scheduling, two types of services are considered: non-real-time polling service (nrtPS) and best effort (BE) service. We propose a flexible and efficient resource allocation and scheduling framework for nrtPS applications to achieve a tradeoff between the delivery delay and resource utilization, where automatic repeat request (ARQ) mechanisms and the adaptive modulation and coding (AMC) technique are jointly considered. For BE service, considering the heterogeneity of subscriber stations (SSs) in IEEE 802.16 networks, we propose the weighted proportional fairness scheduling scheme to achieve the flexible scheduling and resource allocation among SSs based on their traffic demands/patterns. For multicast scheduling, a cooperative multicast scheduling is proposed to achieve high throughput and reliable transmission. By using the two-phase transmission model to exploit the spatial diversity gain in the multicast scenario, the proposed scheduling scheme can significantly improve the throughput not only for all multicast groups, but also for each group member. Analytical models are developed to investigate the performance of the proposed schemes in terms of some important performance measurements, such as throughput, resource utilization, and service probability. Extensive simulations are conducted to illustrate the efficient of the proposed schemes and the accuracy of the analytical models. The research work should provide meaningful guidelines for the system design and the selection of operational parameters, such as the number of TV channels supported by the network, the achieved video quality of each SS in the network, and the setting of weights for SSs under different BE traffic demands.