Network Selection Scheme Research Articles

멀티밴드 해양통신망에서 전송주기를 보장하는 최소 비용의 망 선택 기법

본 논문은 멀티밴드 해양통신망에서 선적 정보를 주기적으로 전송할 때 발생하는 비용을 최소화하기 위해 가용한 네트워크의 전송 비용과 주어진 허용 가능한 최대 지연 범위 이내에서 예상되는 최소 평균 전송 비용을 비교하여 전송 시점을 결정하는 방안을 제시한다. 이때 전송 시점과 해당 네트워크의 선택 과정을 Markov Decision Process (MDP)로 모델링하며, 이에 따라 각 밴드에서의 채널 상태를 2-State Markov Chain으로 모델링하고 평균 전송 비용을 Stochastic Dynamic Programming을 통해 계산한다. 이를 통해 최소 비용의 망 선택 방식이 도출되었으며, 제안된 방식을 사용할 때 고정 주기를 사용하여 정보를 전송하는 방식에 비해 상당한 망 사용 비용을 절감할 수 있음을 컴퓨터 시뮬레이션을 통해 보인다. This paper presents the minimum-cost network selection scheme which determines the transmission instance in the multi-band maritime communication system, so that the shipment-related real-time information can be transmitted within the maximum allowed period. The transmission instances and the corresponding network selection process are modeled by a Markov Decision Process (MDP), for the channel model in the 2-state Markov chain, which can be solved by stochastic dynamic programming. It derives the minimum-cost network selection rule, which can reduce the network cost significantly as compared with the straight-forward scheme with a periodic transmission.

Adaptive Decision Making Strategy for Handoff triggering and Network Selection

Next generation mobile networks (4G) is expected to integrate a large number of wireless technologies. However, this integration yields many challenges such as those pertaining to handoff triggering and decision making. Various approaches have been proposed to solve these problems, yet handoff initiation and network destination selection remain critical issues which are widely based on RSS (Received Signal Strength) measurements. Moreover, the use of context-awareness is very limited in the previous works. This paper proposes a new handoff decision strategy which aims to efficiently deal with handoff triggering and network destination selection with respect to mobile terminal requirements and network capabilities. Furthermore, we introduce a new score function that estimates network preferences for both voluntary and forced handoffs. Additionally, to render easier the accessibility to context information, we develop a context aware mechanism which is based on third party architecture. Finally, simulation results show that compared to RSS-based approaches, the proposed handoff decision strategy has greater respect for users’ requirements and preferences.

Network Selection for Cognitive Radio Based on Fuzzy Learning

Cognitive radio is a promising approach to ensuring the coexistence of heterogeneous wireless networks since it can perceive wireless conditions and freely switch among different network modes. When there are many network opportunities, how to decide the appropriate network selection for CR user's current service is the main problem we study in this paper. We make full use of the intelligent characteristic of CR user and propose a fuzzy learning based network selection scheme, in which the network selection choice is made based on the estimated evaluations of available networks. Multiple factors are considered when estimating these evaluations. Both the outer environment factors directly sensed by CR user (signal strength of the available network and network mode), and also the factor that cannot be determined beforehand and is learnt by our scheme (the bandwidth allocated by the optional network) are considered. From several interactions with the wireless environment, the experience of network selection behavior is accumulated which will direct our scheme to make a proper decision of the network. Two simulations verify that our scheme could not only guarantee a better bandwidth requirement of CR user compared with other three network selection methods, but also shows it to be a reasonable scheme for utilizing the available resources of these networks.

A QoS Awareness Network Selection Scheme for Heterogeneous Networks

A QoS Awareness Network Selection Scheme for Heterogeneous Networks

Seamless Mobility in Heterogeneous Wireless Networks

In next generation of wireless networks, different technologies belonging to one or more operators should be integrated to form a heterogeneous environment based on an IP core network infrastructure. This ensures user mobility and service continuity by maintaining connections when switching between various technologies and it introduces new resources and possibilities for applications. In this context, an automatic interface selection based on instantaneous and practical constraints and user preferences (Quality of Service (QoS) parameters, available resources, security, power consumption, etc) is therefore required. The different network selection and handover schemes proposed in the literature can be classified into three approaches according to who is responsible for making the handover decision: the terminal, the network or thanks to a cooperation between both of them. However, these approaches keep presenting some drawbacks; namely the problem of resources management and network load balancing whenever the selection is controlled by the mobile terminal (MT) and the problem of scalability and unknown operator's management policy whenever the selection is rather controlled by the network. In this article, first we propose a new architecture and new network selection scheme that explicitly take into account the current resource usage and the user preferences. Furthermore, our solution ensures the selection of the most suitable network for each flow while taking into consideration its expectations in terms of QoS. A feasibility study of our architecture is then triggered on a single MT by using typical scenarios and using various algorithms to evaluate their performances.

Network selection in a WiMAX–WiFi environment

The tremendous growth of wireless technologies has introduced the potential of continuous service adaptation to the users’ needs by giving them the ability to be able to select and access the proper network based on different criteria. Moreover, next generation wireless networks have been designed to provide support for multimedia services, with different traffic characteristics and different Quality of Service (QoS) guarantees. However, the expansion of Wireless Local Area Networks (WLANs) and Worldwide Interoperability for Microwave Access (WiMAX) networks poses new research era in the decision of the access network selection. In this paper, the existing access network selection schemes are classified into three categories: the network-centric, the user-centric and the collaborative schemes, and are analyzed respectively. Moreover, we propose a multicriteria access network selection algorithm applied in a WiMAX–WLAN environment, in order to facilitate the provision of high quality services and at the same time to satisfy different types of user Service Level Agreements (SLAs).

A network selection scheme for multicast applications in wireless network convergence

ABSTRACTIn wireless network convergence, each mobile host is expected to have multiple kinds of wireless interfaces. Multicast‐based applications are expected to be widely deployed. In this paper, a new network selection scheme is proposed for a mobile host to select the most appropriate wireless access network to maximize user satisfaction and ISP's profit, simultaneously. We have devised a metric to measure a user's satisfaction and we also developed a ‘normalized network resource’ metric for system profit measure. We have compared our scheme with three other reference schemes, through simulations. Depending on the network deployment situations, our scheme exhibits one‐fifth service disruption time of other reference schemes, while the resource consumption of our scheme is comparable to that of the minimum resource scheme. Overall, the gain of our scheme becomes higher as users move faster and/or the population density increases. Copyright © 2010 John Wiley & Sons, Ltd.

Radio-Resource Management and Access-Control Mechanism Based on a Novel Economic Model in Heterogeneous Wireless Networks

In this paper, we first investigate the radio-resource management and network-selection schemes in heterogeneous wireless networks. Then, we propose a novel economic model to allocate radio resources for both code-division multiple-access (CDMA) networks and wireless local area networks (WLANs). Particularly, the resource-usage constraint is deduced in the CDMA uplink, where the radio resource is allocated with the aim of maximizing the total welfare of the CDMA network while satisfying the signal quality requirement of all mobile users. Moreover, we formulate and solve the optimization problem in the WLAN to maximize the network welfare when the maximum throughput in the WLAN is achieved by controlling the optimum collision probability. An approximated closed-form expression for the network welfare is also given when the assigned bandwidth for each user is close to the bandwidth request. Finally, we design the joint access-control mechanism under different load conditions in coupled heterogeneous networks. Numerical results show that the proposed scheme can achieve approximately 20% more users and 10% more network social welfare, which outperforms the utility-function-based access selection and single network access-control mechanisms in the literature for heterogeneous wireless networks.

QoS based network selection scheme for 4G systems

Exponential growth of user demands on a single convergence platform has brought researchers to explore various aspects/features of Fourth Generation (4G) Mobile Communication System. Selection of application as per the user preference based on QoS (Quality of Service) is one salient feature of 4G. This user-centric system works on the basis to provide best services of the network to the users. In this paper, a selection algorithm has been proposed which provides a better way to implement user preferences as per the features of 4G. Rank based on distance function has been computed for various available services/access technologies, called networks. Weighted distance function is obtained based on multiple QoS parameters as per user needs. The proposed algorithm shows better results compared to single parameter based system, under a heterogeneous network system.

Access network selection strategy using position prediction in heterogeneous wireless networks

Access network selection (ANS) strategy is one of the most important issues in future heterogeneous networks. The current solutions for this issue are not very efficient because they do not consider the motion scenarios and cannot predict the next location for mobile node. In this paper, an effective ANS strategy based on global positioning system (GPS) is proposed. Making use of information such as position coordinates and moving velocity acquired by GPS, the ANS proposed can predict the next point of attachment for mobile node (MN), assist existing ANS strategy to make more reasonable decision, and achieve better performance.

Cross-layer radio resource management in integrated WWAN and WLAN networks

This paper proposes a mobility adaptive network selection scheme in the context of wireless wide area network (WWAN) and wireless local area network (WLAN) radio access technologies (RATs) that supports both real-time (RT) and non-real-time (NRT) service classes. Physical layer information based call admission control (CAC) is considered for the two RATs to enforce service specific QoS requirements. The effectiveness of the cross-protocol-layer information for radio resource management (RRM) in integrated WWAN and WLAN networks is assessed analytically for individual service classes in a multi-service environment using the theory of Markov chains. The impact of non-uniform user and mobility distributions due to the existence of hotspot in the macro-cell area and the effect of network selection parameter measurement errors on the RRM performance are also evaluated. Numerical results show that the proposed network selection scheme minimizes the rate of unnecessary vertical handoffs, thereby providing stable communication without degrading the call blocking probability and call outage probability performance metrics.

Optimal network selection in heterogeneous wireless multimedia networks

The complementary characteristics of different wireless networks make it attractive to integrate a wide range of radio access technologies. Most of previous work on integrating heterogeneous wireless networks concentrates on network layer quality of service (QoS), such as blocking probability and utilization, as design criteria. However, from a user's point of view, application layer QoS, such as multimedia distortion, is an important issue. In this paper, we propose an optimal distributed network selection scheme in heterogeneous wireless networks considering multimedia application layer QoS. Specifically, we formulate the integrated network as a restless bandit system. With this stochastic optimization formulation, the optimal network selection policy is indexable, meaning that the network with the lowest index should be selected. The proposed scheme can be applicable to both tight coupling and loose coupling scenarios in the integration of heterogeneous wireless networks. Simulation results are presented to illustrate the performance of the proposed scheme.

Enhanced network selections in a cognitive wireless B3G world

A network operator of the wireless beyond the third generation (B3G) era will need to be directing terminals to the most appropriate radio networks of its heterogeneous infrastructure. This requires advanced terminal management functionality for conducting optimal network selections, in a seamless to the user manner. This paper enhances network selection schemes by developing functionality for learning the quality of service (QoS) capabilities of candidate networks and by exploiting the acquired knowledge in the network selection. The resulting scheme selects networks that offer the best QoS, taking into account the user needs, policies, the context of operation, and the knowledge. The advantage is that the reliability of the knowledge-based decisions is increased. This enhances the probability of offering the desired QoS to the user and reduces some of the related operational overheads in the network. The learning functionality is influenced by Bayesian networks. The computational effort for the development of the knowledge is shown to be minimal. Results show the behavior of the scheme in terms of knowledge development, respective computational effort required, and network selections made. In general, the paper contributes to the introduction of cognitive systems in the wireless B3G world.

Dynamic pricing for service provisioning and network selection in heterogeneous networks

In this paper, we model a market-based cognitive radio network where multiple wireless service providers (WSPs) offer competitive prices to users. We assume that WSPs use a mix of access technologies to provide a wide variety of wireless services (e.g., voice, data etc.) with a certain level of QoS while maximizing their revenues. Using a non-cooperative game model, we propose differentiated pricing strategies for the WSPs and users. We also propose an optimal strategy for access network selection by the service providers which minimizes the effect on QoS of the existing users and increases self–coexistence. We show that, in order to achieve Nash equilibrium, it is in the best interest of both WSPs and users to adhere to the proposed strategies. Performance issues from both providers’ and users’ perspectives are studied through analytical computations and simulation experiments. Analysis shows that our proposed pricing policy represents the oligopoly market, i.e., exhibiting larger sensitivity to a new provider when the number of existing providers is low and lower sensitivity when the number of existing providers is high. Simulation results demonstrate that the proposed pricing and network selection policies benefit both users and WSPs.

Cost-Function-Based Network Selection Strategy in Integrated Wireless and Mobile Networks

Wireless and mobile networks have experienced great success over the past few years. However, any single type of wireless and mobile network cannot provide all types of services, e.g., wide coverage and high bandwidth. An integrated wireless and mobile network is introduced by combining these different types of wireless and mobile networks, which can provide more comprehensive services. In an integrated wireless and mobile network, a mobile terminal that is equipped with heterogeneous network interfaces is capable of accessing all the available networks. Therefore, how to select a desired network is an important issue for the integrated wireless and mobile network. Although some network-selection strategies have been proposed, most of them are designed to meet a user's individual needs, such as the bandwidth, the access fee, or the power consumption. The system performance also has not been touched. In this paper, we propose a cost-function-based network selection (CFNS) strategy in an integrated wireless and mobile network from a system's perspective, which also considers a user's needs. We also analyze the system performance of the proposed network-selection strategy by using a theoretical model and extensive simulations. The results obtained show that the proposed network-selection strategy affects multiple system parameters, which needs to be handled carefully.

Connectivity opportunity selection in heterogeneous wireless multi-hop networks

This paper addresses the problem of selecting the best connectivity alternative for the user in a generic Heterogeneous Wireless Multi-hop Network (HWMN), integrating distinct wireless technologies and multi-mode cooperating stations. We propose a Connectivity opportunity Selection Algorithm (CSA) that uses network state information and mobility profile information to select the best connectivity based on the applications’ requirements. We provide a simulation-based performance evaluation of the CSA and compare it with a greedy network selection scheme. Furthermore, we propose an extended reference model that allows the integration of the concept of connectivity opportunity and our proposed CSA with the framework being defined by the upcoming IEEE 802.21 standard for Media Independent Handover services.

Network selection strategy in heterogeneous multi-access environment

Network selection mechanisms play a vital role in ensuring quality of service in the heterogeneous multi-access environment. In this article we develop a network selection scheme for an integrated cellular/wireless local area network (WLAN) system to guarantee mobile users being always best connected (ABC). The proposed scheme comprises three parts, with the first detecting the availability of WLAN, while the second applying an analytic hierarchy process (AHP) to decide the relative weights of evaluative criteria set according to user preferences, network condition and service applications, the third normalizing parameters and calculating decision-making index. Simulations conducted in a heterogeneous system with UMTS and wireless LAN reveal that the proposed network selection technique can effectively decide the optimum network through making trade-offs among network condition, user preference, and service application, while avoiding frequent handoffs.

A NEW 4G ARCHITECTURE PROVIDING MULTIMODE TERMINALS ALWAYS BEST CONNECTED SERVICES

In recent years, wireless communication technology has undergone a tremendous change. Various radio access technologies have been deployed all over the world. The 4G mobile system was proposed to integrate all of these radio access technologies into a common network called the open wireless architecture (OWA) platform. As one of the main features of a 4G mobile system, always best connected (ABC) services enable users to choose the best available access networks in a way that best suits their needs. A new architecture capable of supporting ABC service is proposed in this study. There are three parts to the proposed architecture. First, a novel access discovery mechanism that integrates service location protocol and location-based service is presented. Second, a new personalized network selection scheme is put forward. Users can select their personalized "best" network by changing weight factors and constraints in a single objective optimization problem. Third, a seamless handover mechanism based on Mobile IPv6 is proposed. The mechanism supports end-to-end quality of service. Through analysis, this architecture demonstrates that it has benefits not only for network operators, but also for users

Network selection in an integrated wireless LAN and UMTS environment using mathematical modeling and computing techniques

The increasing demand for broadband service, at least in hot spot areas, in today's wireless communications is causing cellular network providers to consider the integration of 3G cellular systems and wireless LAN. This has the particular advantage of high data rates and unlicensed spectrum. Consequently, network selection techniques play a vital role in ensuring quality of service in heterogeneous networks. In this article we develop a network selection scheme for an integrated cellular/wireless LAN system. The design goal is to provide the user the best available QoS at any time. The proposed scheme comprises two parts, with the first applying an analytic hierarchy process (AHP) to decide the relative weights of evaluative criteria set according to user preferences and service applications, while the second adopts grey relational analysis (GRA) to rank the network alternatives with faster and simpler implementation than AHP. Simulations conducted in a heterogeneous system with UMTS and wireless LAN reveal that the proposed network selection technique can effectively decide the optimum network through making trade-offs among network condition, user preference, and service application, while avoiding frequent handoffs.