Badii Jouaber

On the use of network QoS reputation for vertical handover decision making

Efficient vertical handover mechanisms are required to provide service continuity over available and upcoming heterogeneous wireless access networks. They should provide low delays and good accuracy to meet service requirements. In the literature, proposed mechanisms rely on a rich knowledge of users ambient environments and contexts. The outcomes are complex mechanisms that require significant amount of resources and processing time. Reputation is a rating concept already used in ad hoc security, social and business fields. It is intended to deliver fast decisions based on the analysis of users experiences in similar conditions. In this paper, we propose the use of a reputation system to speed up vertical handover (VHO) decisions in complex wireless environments. The proposed approach can be used for initial attachments and VHO decisions. It is based on simplified rating functions reflecting a contextual QoS, experienced by previous users. Discussions and early performance evaluations are provided.

Reputation for Vertical Handover decision making

To meet the continuously increasing demands and requirements of mobile users, next generation wireless systems are more and more relaying on the coexistence of heterogeneous wireless networks. The objective is to provide any time and anywhere connectivity to users. One of the main challenges in such a heterogeneous environment is mobility management, including network selection and Vertical Handover (VHO) procedures. In this paper, we propose a VHO management solution combining the use of reputation as a Quality of Experience (QoE) indicator for fast decision-making and the Stream Control Transmission Protocol (SCTP) as a mobility protocol. This reputation-based Vertical Handover solution operates on the previous observed experiences of users within the different available networks to make fast decisions and uses the SCTP protocol that provides multihoming facilities. Performance results demonstrate that the proposed handover scheme provides seamless mobility, with low latency, good throughput and almost no packet loss.

An enhanced media independent handover framework for vertical handover decision making based on networks' reputation

Integrating heterogeneous wireless networks invokes many architectural and technical challenges regarding networks cooperation, QoS and service continuity guarantees. In this paper, we focus on one of the main processes related to networks integration. It is the Vertical Handover (VHO), a critical process that requires high efficiency and low delays. We consider the Media Independent Handover architecture, proposed by the IEEE 802.21 working group in order to provide the required information for handover and mobility management entities. We propose an enhanced IEEE 802.21 Media Independent Handover framework (eMIH) that integrates a Vertical Handover Management Engine (VHME) for fast handover decision-making based on networks reputation, a new quality metric. It is a new cooperative indicator based on previous experiences and can insure higher efficiency and lower delays for vertical handover decisions in complex and rich environments such as integrated heterogeneous wireless networks.

Dynamic-address-allocation based scalable routing protocol in context of node mobility

Mobile party (MP) has been recently proposed to solve the problem of scalability in wireless mesh network, which is an enhancement of a dynamic address allocation (DAA) based routing protocol called party. Party protocol has been proposed for self organizing ad hoc networks where scalability of routing protocol is the main issue. But MP still lacks an efficient mechanism for DAA in case of node failure or movement. In this paper, we propose an enhancement to MP to cope with node mobility in general self-organizing network and hence call it enhanced MP (EMP). Performance of EMP is extensively evaluated by network layer simulation, which shows that EMP performs well with node mobility and provides better scalability in terms of signaling overhead. Our analysis also reveals that achieving better performance of DAA based routing is more challenging with higher node mobility compared to static case.

QoS-HAN: QoS provisioning in Home Automated Networks over IEEE 802.11n

Demands for QoS challenging wireless multimedia services are continuously increasing for both professional and entertainment needs. Efficient wireless technologies, able to offer the corresponding throughput and QoS are required. The IEEE 802.11n is the latest wireless standard. It introduces many improvements at both Physical and MAC layers. However, and despite the increase of the physical data rate, the large overhead associated with channel access and packet transmission schemes reduces its overall efficiency, mainly at the MAC layer. In this paper, we propose QoS-HAN: a new scheme for the 802.11n aggregation process. QoS-HAN is mainly designed to meet the requirements of multimedia services over Home Automated Networks (HAN). It takes into consideration the size of the packet during aggregation. The proposed scheme is evaluated and examined for different types of traffic. Simulation results demonstrate the efficiency of the proposed scheme in terms of throughput, delay and PDR.

Seamless Handoff Solution For Nested Mobile Networks

Ensuring seamless mobility for users is becoming one of the main objectives of ongoing research activities in the field of data telecommunications. More over, if some proposals are efficient in reducing handoff latency for single mobile hosts, adequate solutions are still required for moving networks. The NEtwork MObility protocol (NEMO), designed to provide network mobility, is not efficient to offer low latency handoff in the case of nested mobile networks because it uses fairly sub-optimal routing. In this paper, an optimized solution to reduce handoff latency for Nested Mobile Networks is proposed. This solution minimizes the registration delay component of the overall handoff latency. The paper describes the new architecture and mechanisms and provides simulation results indicating performance compared to the basic NEMO solution.

A Nash Stackelberg approach for network pricing, revenue maximization and vertical handover decision making

Radio resource and mobility managements are becoming more and more complex within nowadays rich and heterogeneous wireless access networking systems. Multiple requirements, challenges and constraints, at both technical and economical perspectives have to be considered. While the main objective remains guaranteeing the best Quality of Service and optimal radio resource utilization, economical aspects have also to be considered including cost minimization for users and revenue maximization for network providers. In this paper, we propose a game theoretic scheme where each available network plays a Stackelberg game with a finite set of users, while users are playing a Nash game among themselves to share the limited radio resources. A Nash equilibrium point is found and used for vertical handover decision making and admission control. We also introduce in the proposed model the users requirements in terms of quality of service according to its running application and the network reputation that is conducted from the users quality of experience and we study the effect of these parameters on the network pricing and revenue maximization problems.

A joint AOA, AOD and delays estimation of multipath signals based on beamforming techniques

Angle of Departure (AOD) and Delay of Arrival (DOA) information is added to beamforming techniques to provide improved and more robust estimates of Angle of Arrival (AOA) and localization. A joint AOA, AOD and DOA algorithm based on the Capon Beamformer is proposed to reduce complexity and computation time compared to subspace-based methods. The proposed approach works even if the number of multipaths exceeds the number of antenna elements. Simulation results are provided to assess the improvements in channel estimation for a multiple antenna array.

Energy saving by Base Station pooling: A signaling framework

Energy consumption is among the major problems faced by cellular operators. In metropolitan areas, cellular network is divided into smaller cells due to high traffic. During low traffic period e.g., at midnight, Base Stations are underutilized but remain active and consume energy. In this paper, we propose two signaling frameworks for pooling the Base Stations of different cellular operators in a single cell during low traffic. The first Framework can be deployed rapidly with existing infrastructure. While the second framework can be used with Base Stations with enhanced capabilities. We consider cellular network with real Base Stations location in Paris region. We have taken blocking probability as Quality of Service parameter. Proposed signaling frameworks take into account call processing, subscribers soft handover between different operators Base Station. In this way, up to 66% energy saving can be achieved for three different service providers in a single cell at low traffic period which also helps in the reduction of cellular radiation.

A two-layered virtualization overlay system using software Avatars

Virtualization is a promising approach to meet the objectives of next generation networks. It will enable building pervasive systems, with the possibilities of automated adaptation and provision of personalized services for users with different needs and contexts. In this paper, we propose the use of Avatars: software delegates to hide heterogeneity between entities such as networks, users, services and any resource or device. Avatars act at an abstraction overlay level, on behalf of their represented entities. They carry information and intelligence (workflows) and cooperate to make decisions like the reconfiguration of the entity they stand for. A software agents-based implementation is then proposed and evaluated.