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Shen, WeiNetwork Selection Strategies and Resource Management Schemes in Integrated Heterogeneous Wireless and Mobile Networks
PhD, University of Cincinnati, 2008, Engineering : Electrical Engineering

Wireless and mobile networks (WMNs) are witnessing a great success inrecent years. Although there are different types of WMNs (e.g., cellular networks, WLANs, etc.) that can provide different types of services (e.g., different bandwidth and coverage), any single type of existing WMN is not able to provide all types of services such as high bandwidth with wide cov- erage. In order to provide more comprehensive services, a concept of integrated heterogeneous wireless and mobile network (IHWMN) is introduced by combing different types of WMNs. Additionally, with the advance of software defined radio (SDR) technologies, it is possible to integrate multiple WMN interfaces into a single mobile terminal and let the terminal be able to access multiple WMNs. It is obvious that the introduction of IHWMN as well as multi-interface terminal brings more flexible and plentiful access options for mobile users. However, it faces great challenges, such as the architecture of network integration, network selection strategies, handoff scheme, resource allocation, etc. Although IHWMN is a very promising candidate for the future WMNs, a lot of problems have to be solved before launching to the commercial market.

In this research thesis, we briefly review the existing work for IHWMN. Then, traffic and system models are proposed for IHWMNs. Based on the proposed models, we tackle the network selection problem in IHWMNs, which is required to determine which network should be accessed. A cost-function-based network selection (CFNS) strategy is proposed based on system’s perspective, which also takes into account of the user’s needs. Theoretical model is used to evaluate the system performance of the proposed CFNS strategy and simulations are also conducted to verify our analysis. Then, we propose preemption-based resource management schemes to support real-time and non-real-time traffic in IHWMNs. The proposed resource management schemes take advantage of heterogeneities of multiple traffic and networks as well as moving nature of users. We further design an algorithm to achieve the fairness between the real-time and non-real-time traffic. The analytical results show that the proposed resource management schemes provide the best service to non-real-time traffic while satisfying the QoS requirements of real-time traffic. In the last, we address the resource management from different perspective. A traffic-based resource management scheme (TRMS) is firstly introduced, which takes advantage of the heterogeneity of traffic and networks as well as user’s satisfaction. We then use Markov decision process to model the resource management scheme of multiple traffic in IHWMNs and propose a Q-learning-based resource management scheme (QRMS) to allocate the resource. The issues addressed in this thesis provide many insights into characterizing the emerging problems in IHWMNs. The analytical and simulation methods applied in this thesis will be useful for the research and development in IHWMNs.

Committee:

Qing-An Zeng (Committee Chair); Kenneth Berman (Committee Member); Raj K. Bhatnagar (Committee Member); Wen-Ben Jone (Committee Member); Heng Wei (Committee Member)

Subjects:

Computer Science

Keywords:

integrated heterogeneous wireless and mobile networks; network selection; resource management; multiple traffic

CAVALCANTI, DAVE ALBERTO TAVARESINTEGRATED ARCHITECTURE AND ROUTING PROTOCOLS FOR HETEROGENEOUS WIRELESS NETWORKS
PhD, University of Cincinnati, 2006, Engineering : Computer Science and Engineering
One of the main challenges in next generation wireless networks is to integrate heterogeneous wireless technologies to provide seamless connectivity, with guaranteed Quality of Service (QoS), to mobile users “anytime, anywhere and with any device”. In this dissertation, we investigate the problem of integrating cellular networks and Wireless Local Area Networks (WLANs) with the multi-hop communication paradigm used in Mobile Ad hoc Networks (MANETs) to exploit all the connectivity alternatives available to different types of Mobile Stations (MSs). We propose an integrated architecture based on three basic functionalities, namely, topology discovery, gateway discovery, and link quality estimation. We combine these three functionalities into an integrated routing mechanism that exploits all connectivity alternatives available in a generic heterogeneous scenario. Then, we provide a simulation-based analysis of our architecture and integrated routing mechanism in different heterogeneous networking scenarios. Our results show improvements in network’s capacity and coverage achieved by our architecture as compared to isolated networks. The results also highlight the importance of the link quality estimation in providing QoS to users, as well as indicate that multi-hop links can be exploited in a controlled network configuration, but the QoS in multi-hop routes cannot be always guaranteed. Furthermore, we address the problem of selecting the best connectivity opportunity for a given service type based on the applications’ QoS requirements, as well as on the network condition and user mobility profile. We propose the Connectivity opportunity Selection Algorithm (CSA) that allows MSs to select the connectivity opportunity most appropriate for a given type of service and mobility profile. Furthermore, we describe how our proposed selection algorithm can be introduced into the IEEE 802.21 standard for Media Independent Handover services.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

Heterogeneous Wireless Networks.; Routing Protocols for Heterogeneous Wireless Networks; Multi-hop communications in integrated wireless networks; network selection; always best connectivity

Mahadevan, SrisudhaNetwork Selection Algorithm for Satisfying Multiple User Constraints Under Uncertainty in a Heterogeneous Wireless Scenario
MS, University of Cincinnati, 2011, Engineering and Applied Science: Computer Science
The constant evolution of various wireless access technologies has led to an advancement in the communication domain where mobile clients (MCs) are equipped with multiple interfaces for simultaneous access to different types of networks. This heterogeneous wireless scenario satisfies the user's preferences and offers the desired quality of service (QoS). Route selection satisfying multiple constraints has proven to be NP-Complete and various approximation schemes exist which consider the network state resources to be fixed and complete. Additionally, in practical scenarios, the user's constraints are imprecise and vague and the changing network conditions force the condition of uncertainty to exist in a routing mechanism. This thesis focuses on the imprecise and dynamic nature of network parameters and maps it to uncertain user constraints. We, hence consider a heterogeneous wireless network (HWN) and propose a novel approach to identify the key network metrics that satisfies the user's criteria. Our design of a fuzzy model maps the underlying uncertainty in the metrics to crisp values and demonstrates the stability of our proposed technique through extensive simulations and analysis. In order to satisfy the user's imprecise demands, we consider the problem of decision making in a HWN where emphasis is on selecting the best network interface to forward the data. We propose an enhanced minimization of maximal regret (MMR) approach to rank the available network interfaces by considering pure uncertainty in a user's constraint. MCs state their needs based on application requirements and thus, we implement a generalized MMR and include Ordered Weighted Averaging (OWA) operators to enable each MC to efficiently select the best possible alternative. The weights utilized in OWA are modeled using application characteristics. Our simulations and experiments compare the sensitivity of user demands depicted in MMR and OWA to that of existing multiple attribute decision making (MADM) algorithms. Simulation results prove that variability in a user's preference and changes in a network scenario can impact decision making and influence the routing process.

Committee:

Dharma Agrawal, DSc (Committee Chair); Chia Han, PhD (Committee Member); Carla Purdy, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Network Selection;Heterogeneous Wireless Network;Fuzzy Logic;Decision Making;Multiple metrics;Uncertainty

Luan, HaoPerformance Analysis of Integrated Multihop Heterogeneous Networks
MS, University of Cincinnati, 2010, Engineering : Computer Science
Next-generation network (NGN) will see an integration of various types of wireless networks, which provides mobile users with seamless and pervasive network connectivity. One of the major challenges of the integration is the network selection strategy. In this thesis, we will propose a network selection strategy that employs the concept of multihop ad hoc network (MANET) based on multiple traffic types. Furthermore, we add channel reservation method to the scheme in order to further reduce voice call blocking probability. We also try to reduce the traffic burden of wireless local area network (WLAN) by requesting services from the cellular network before retransmissions in WLAN when the number of packet retransmissions has exceeded the threshold. System performances are evaluated through extensive simulations and the results show that our schemes not only achieve lower new/handoff voice call blocking probability, but also lead to increased average WLAN throughput compared to the single-hop connection scheme.

Committee:

George Purdy, PhD (Committee Chair); Qing An Zeng, PhD (Committee Member); Yizong Cheng, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

integrated heterogeneous network;network selection;CSMA/CA with RTS/CTS

Zhu, ChengResource Management Scheme and Network Selection Strategy for Integrated Multiple Traffic Heterogeneous Systems
MS, University of Cincinnati, 2009, Engineering : Computer Science

The wireless and mobile networks (WMNs) have grown in an explosion fashion in recent years. The future wireless and mobile network system will allow different types of networks coexisting in some partial of service area and cooperate with each other, and thus an integrated heterogeneous networks system will be formed. On the other hand, the future terminals will be equipped with multiple radio interfaces that can access different types of networks. With the terminals receiving multiple services and performing vertical handoffs between different types of networks, it has imposed great challenges for the integration of heterogeneous wireless networks. One of them is how to effectively manage the resources of different types of networks for a better entire system performance. Another is how to make an efficient network selection to access among different types of networks. Most of the literatures on the first issue discussed the resource management with single type of traffic or network, while few works have considered the multiple traffic in an integrated heterogeneous network environment. On the second issue, most of the works are policy based selection strategies. The policy based selection strategy is to design different selection policy functions, which combine network conditions, and user’s preference, etc. in order to make a network selection decision. However, the user’s traffic types, i.e. the real-time (voice, video) and non-real-time (data) service, have not been identified in the policies.

Based on these, in this thesis, we proposed a resource management and a network selection strategy respectively. Firstly a novel preemption-based resource management scheme supporting multiple traffic in heterogeneous network system is proposed. The proposed scheme takes advantage of the service features of different types of traffic and mobile user’s cell dwelling time, as well as moving nature of users. The real-time traffic is allowed to preempt non-real-time traffic according to the estimated mobile user’s cell dwelling time if necessary. Next, the network selection strategies have been studied. In our approach, we identify the traffic types in the policy functions. Because different traffic types will have different service requirements, based on this, we give them with different priorities and channel reservation in the policy function to improve the performance on real-time traffic with tradeoffs on non-real-time traffic at an acceptable level. A network selection scheme is proposed which identifies the user’s traffic by modifying the policy function based on their traffic type. The purpose is to restrict non-real-time traffic’s network selection options in order to guarantee the real-time traffic to have more network resource and better system performance. The proposed schemes are evaluated through extensive simulations and the results show that the proposed schemes can significantly improve the system performance.

Committee:

Raj Bhatnagar, PhD (Committee Chair); Anca Ralescu, PhD (Committee Member); Carla Purdy, PhD (Committee Member); Qing An Zeng, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Heterogeneous network system; Network selection; Resource management

Wang, XiaoyuanNetwork Selection and Rate Allocation in Heterogeneous Wireless Networks and Systems
MS, University of Cincinnati, 2009, Engineering : Computer Science

Heterogeneous wireless network (HWN) technology has emerged in the next generation mobile networks, which enables mobile client (MC) to simultaneously communicate with multiple heterogeneous access networks for better quality of services (QoS) and lower service cost. By the context of conventional network protocols, separately and independently operating network interfaces cannot fully utilize the potential of a HWN.

In this thesis, we model and analyze a HWN and system. The issues are identified as the multi-MAC management between MCs and access networks, and the multi-network (multi-NET) management between application servers and access networks. We propose a multi-MAC management scheme over multiple heterogeneous interface MACs to optimize multi-application performance with network selection and rate allocation for uplink traffic. We also propose a multi-NET management scheme for multi-user performance optimization in the downlink traffic, which is network-centric and distributes traffic into multiple access networks by supporting the inter-networking operations. Besides necessary optimization algorithms, procedures to implement our schemes are also provided.

Committee:

Dharma Agrawal, DSc (Committee Chair); Wen-Ben Jone, PhD (Committee Member); Chia-Yung Han, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Heterogeneous Wireless Networks;Network Selection;Optimization;Rate Allocation