Seamless handover among heterogeneous wireless networks

The present thesis introduces decision criteria for the handover among heterogeneous wireless networks also known as vertical handover. The goal is to select the best network that can support the required service(s) and avoid excessive switching among di erent networks in order to minimize service interruptions and power consumption. Firstly we address the vertical handover between speci c broadcast technologies using a single aggregate function (SAF), then we generalized the approach in order to consider heterogeneous technologies and their possible optimization at link layer. To avoid unnecessary handover in the SAF approach we introduced a probabilistic approach that has minimal computational complexity while maintaining a trade-o between received bits and number of vertical handovers. In the last part of the present thesis we propose an approach based on a multi-criteria decision technique that permits to consider the out-of-service parameter and includes parameters that are a ected by a degree of uncertainty

Seamless handover in heterogeneous wireless networks

The present thesis introduces decision criteria for the handover among heterogeneous wireless networks also known as vertical handover. The goal is to select the best network that can support the required service(s) and avoid excessive switching among di erent networks in order to minimize service interruptions and power consumption. Firstly we address the vertical handover between speci c broadcast technologies using a single aggregate function (SAF), then we generalized the approach in order to consider heterogeneous technologies and their possible optimization at link layer. To avoid unnecessary handover in the SAF approach we introduced a probabilistic approach that has minimal computational complexity while maintaining a trade-o between received bits and number of vertical handovers. In the last part of the present thesis we propose an approach based on a multi-criteria decision technique that permits to consider the out-of-service parameter and includes parameters that are a ected by a degree of uncertainty

Efficient transport of IP flows over IEEE802.11 wireless mesh networks

Wireless Mesh Networks (WMNs) based on the IEEE802.11 standards can be used as convenient replacements of wireline networks in the context of home networking to provide users with a variety of services inside the home context for their low cost and easiness of deployment. However, in order to effectively support multimedia as well as ordinary traffic through a WMN infrastructure, traffic control is generally needed as wireless communications, especially in mesh network configurations, can be affected by significant congestion and channel impairments problems. In this work we are focusing on performance assessment and enhancement in IEEE802.11 WMNs. Experimental results are presented using simulation models of IEEE802.11b technology obtained through the open source INET framework of OMNET++ simulator

Geometric cross-layer QoS parameters based seamless vertical handover procedures in presence of adaptive modulation and coding

Vertical handover (VHO) procedure facilitates service continuity in a heterogeneous wireless scenario under varying network as well as channel conditions. Decision criteria for VHO are, mainly, designed to maximize a combination of network parameters in order to guarantee a satisfying quality of service and maximize network operators and/our users expectation. The objective of this work is to formalize the VHO decision criteria as a QoS constrain bound problem and propose two strategies that permits to achieve QoS constrains without wasting resources. The former that minimize the power consumption and the latter that minimize the number of VHO. Numerical results are provided in order to compare the two strategies. © 2011 IEEE

Soft Multi-Criteria Decision Algorithm for Vertical Handover in Heterogeneous Networks

Choosing or switching between heterogeneous networks according to the highest performance in terms of quality of service is largely inefficient in vertical handover. In fact a service may have unstable performance and require highly frequent vertical handover procedures. In this paper we consider the impact of statistical fluctuations of performance parameters (decision under risk) and propose a soft algorithm that exploits the statistical knowledge in order to reduce outage probability

Vertical handover among broadcast networks

In this article we propose strategies for optimization of vertical handover among broadcast networks. The specific technologies of DVB-H and UMTS/MBMS are taken into account for the modelling of technological parameters including energy consumption and frame loss. Energy consumption is important in a mobile context in order to maximize the possible service duration while frame loss must be considered in order to provide services with an acceptable quality of experience. The proposed strategies are based on two different functions: a ratio between the energy consumption and the frame loss along and a linear objective function. The two function are compared with functions based on only one parameter and against the theoretic frame loss and energy consumption. The paper gives numerical results obtained through simulations in different mobility conditions in order to assess the performance of the proposed functions in terms of frame loss and energy consumption as well as in frequency of vertical handovers. © 2009 IEEE

Application QoS management and session control in a heterogeneous home network using inter-MAC layer support

none4This paper deals with the management of application QoS and session control in next generation home networks. These networks will be realized through the integration of heterogeneous communication technologies that will coexist and interoperate thanks to the introduction of a convergence layer, namely the Inter-MAC layer, as defined, for example, within the EU OMEGA project. Such layer is capable to efficiently guarantee a pre-defined level of Quality of Service to modern applications by means of an advanced management of the network resources. However, a unified mechanism to initiate the high level network application, especially in order to provide the signalling information containing user's desired level of QoS to the Inter-MAC layer and to orchestrate the setup procedure is actually missing. This document aims at proposing an innovative architectural and procedural definition of the home context considering the presence of two existing protocols, namely UPnP-QoS and SIP, and their coupling with Inter-MAC to provide a QoS enabled framework in the home context. Copyright ?????? 2010 The authors.M. Castrucci; G. Oddi; G. Tamea; V. SuraciM., Castrucci; Oddi, Guido; G., Tamea; Suraci, Vincenz

A Probability-based Vertical Handover Approachto Prevent Ping-Pong Effect

Vertical handover is a new trend for heterogeneous next generation networks, in order to assure ubiquitous and seamless connectivity to mobile users. This paper presents a novel vertical handover algorithm based on a probabilistic approach for decision strategy. The proposed technique deals with the assessment of a Wrong Decision Probability (WDP), which assures a trade-off between network performance maximization and mitigation of the ping-pong effect. The WDP is evaluated using network parameters, such as instantaneous estimated goodput. Analytical and simulation sections are presented in order to validate the VHO assessment. Basically, a simulated network scenario has been considered, where a mobile device moves at low speed. Specifically, simulated results have been evaluated for typical wireless access technologies (i.e. with small and medium transmission ranges). Results depict the effectiveness of the proposed vertical handover algorithm in terms of maximization of cumulative received bits, and minimization of unwanted and unnecessary vertical handovers. © 2009 IEEE

A combined vertical handover decision metric for QoS enhancement in next generation networks

Vertical handover (VHO) techniques are applied when mobile users require service continuity and a seamless roaming between heterogeneous networks. A VHO decision can be taken on the basis of physical parameters, such as the received signal strength (RSS), data rate and signal-to-interference and noise ratio (SINR). In this paper, we compare three VHO decision criterions, each of them based on different physical metrics. A smart combination of several VHO criterions is the core of our proposed approach, which uses not only RSS or SINR parameters, but also a hybrid mixture from different wireless access networks. To improve quality of service for mobile users, a data rate gain parameter is introduced that lets an efficient VHO be executed. Simulation results of the proposed VHO approach are in terms of both end-users efficiency, i.e. cumulative received bits, and network performances, i.e. VHO frequency. © 2009 IEEE