This chapter contains sections titled: Product Definition for Broadband Wireless Systems Technology Drivers Evolving Wireless Broadband Market Segments Open Systems and Intelligence at the Edge Radio Network System Engineering References

Always Best Connected

Review: An overview of vertical handover techniques: Algorithms, protocols and tools

Mobile terminals in 4G heterogeneous wireless networks continuously undergo horizontal and vertical handovers. In order for a mobile terminal to be connected to a network in the best possible way in terms of QoS performance and energy consumption, access network selection as the main decision within the handover process is obviously crucial. This paper presents a novel method that takes into account user preferences, network conditions, QoS and energy consumption requirements in order to select the optimal network which achieves the best balance between performance and energy consumption. The proposed network selection method incorporates the use of parameterized utility functions in order to model diverse QoS elasticities of different applications, and adopts different energy consumption metrics for real-time and non-real-time applications. User preferences are easily configured for different application and situation contexts through the use of linguistic assessments and their representation as triangular fuzzy numbers. The aggregation of multiple criteria for the calculation of the overall rating of the networks is performed through the use of the Fuzzy Set Representation TOPSIS method that resolves the issue of inconsistency related to conflicting decision criteria and is modified through the use of the employed utility functions for the elimination of the ranking abnormality problem. Finally, simulations are conducted in order to demonstrate how the proposed method would work and confirm its suitability and effectiveness.

A utility-based fuzzy TOPSIS method for energy efficient network selection in heterogeneous wireless networks

Many researchers have been working on the performance analysis of caching in Information-Centric Networks (ICNs) under various replacement policies like Least Recently Used (LRU), FIFO or Random (RND). However, no exact results are provided, and many approximate models do not scale even for the simple network of two caches connected in tandem. In this paper, we introduce a Time-To-Live based policy (TTL), that assigns a timer to each content stored in the cache and redraws the timer each time the content is requested (at each hit/miss). We show that our TTL policy is more general than LRU, FIFO or RND, since it is able to mimic their behavior under an appropriate choice of its parameters. Moreover, the analysis of networks of TTL-based caches appears simpler not only under the Independent Reference Model (IRM, on which many existing results rely) but also with the Renewal Model for requests. In particular, we determine exact formulas for the performance metrics of interest for a linear network and a tree network with one root cache and N leaf caches. For more general networks, we propose an approximate solution with the relative errors smaller than 10−3 and 10−2 for exponentially distributed and constant TTLs respectively.

/pdf/analysis-of-ttl-based-cache-networks-57oc0kgnc4.pdf

Analysis of TTL-based cache networks

Radio resource management in emerging heterogeneous wireless networks

The proliferation of wireless technologies and their ever increasing popularity and pervasiveness made it possible to have mobile terminals (MTs) equipped with a myriad of network interfaces. It is then becoming essential to offer vertical handoff solutions where users can move among various network types efficiently and seamlessly. A variety of mechanisms supporting vertical handoffs by selecting the best possible network interfaces have been proposed. The evaluation of these mechanisms, however, remains a complicated task and no known proposal is completely adequate to evaluate these mechanisms. In this paper, we propose a novel methodology for evaluating vertical handoff decision mechanisms. This methodology takes into account the current context, different realistic user mobility models, users preferences, applications requirements as well as wireless access technologies specificities and QoS parameters. The proposed methodology provides an adequate framework to investigate vertical handoff mechanisms (VHMs) and evaluate their performances. Then, we demonstrate our methodology on a VHM called Ubique.

A Methodology for Evaluating Vertical Handoff Decision Mechanisms

In the recent years, wireless communication systems have received increased interest in commercial applications. Different kind of wireless public access have become increasingly available in various areas like airports, stations and shopping centers as well as at office or at home. Mobile terminals, such as phones or laptops, are often equipped with several network interfaces and may use simultaneously several access networks. For instance it is nowadays common to have UMTS, WiFi, BlueTooth, and even WiMAX interfaces on a single mobile device. Each of them can be attached to different Internet providers offering seamless connectivity, high-speed multimedia services with different billing models and security levels. In this paper, we focus on an advanced middleware that allows, through a comprehensive profile management, the support of automatic interface configuration and per-flow interface selection. The system takes into account preferences given by the terminals owner, the users and the applications. This middleware makes the terminal to be always "best" connected and provides service continuity in case of vertical handover. As illustration, we show how the proposed middleware allows cost-effective management of a fleet of terminals.

Automatic multi-interface management through profile handling

In 4G networks, various wireless access technologies will be integrated into a heterogeneous network based on an IP core network infrastructure. Thus, numerous works focus on mobility and vertical handover management to allow multiple-interfaces mobile terminals to roam seamlessly between these access networks. The different handoff schemes can be classified into three approaches according to where the decision to handoff is made: within the terminal, the network or thanks to a collaboration between them. However, these approaches still present some drawbacks; namely the problem of resource management whenever the handover is controlled by the mobile terminal (MT) and the problem of scalability and complexity whenever the handover is rather decided by the network. In this paper, we propose a new approach that explicitly takes into account management requirements, the current resource usage and user preferences. Furthermore, our solution provides means to select the "best-suited" network for each application according to its expectations in terms of QoS. A feasibility study of our solution is then conducted on a single mobile terminal by using typical scenarios and applying various algorithms to evaluate their behaviors.

Towards an Architecture for Mobility Management and Resource Control

Traffic measurement and analysis are crucial management activities for network operators. With the increase in traffic volume, operators resort to sampling primitives to reduce the measurement load. Unfortunately, existing systems use sampling primitives separately and configure them statically to achieve some performance objective. It becomes then important to design a new system that combines different existing sampling primitives together to support a large spectrum of monitoring tasks while providing the best possible accuracy by spatially correlating measurements and adapting the configuration to traffic variability. In this paper, and to prove the interest of the joint approach, we introduce an adaptive system that combines two sampling primitives, packet sampling and flow sampling, and that is able to satisfy multiple monitoring tasks. Our system consists of two main functions: (i) a global estimator that investigates measurements done by the different sampling primitives in order to deal with multiple monitoring tasks and to construct a more reliable global estimator while providing visibility over the entire network; (ii) an optimization method based on overhead prediction that allows to reconfigure monitors according to accuracy requirements and monitoring constraints. We present an exhaustive experimental methodology with different monitoring tasks in order to assess the performance of our system. Our experimentations are done on our MonLab platform that we developed for the purpose of this research.

https://hal.inria.fr/hal-00682652/document

A multi-task adaptive monitoring system combining different sampling primitives

Mobile wireless technologies have seen an immense growth in the recent years. Different kink of wireless public access have become increasingly available in areas like airports, stations and shopping centers as well as at office or at home. Mobile terminal such as phone or laptop are often equipped with several network interfaces and may use several access networks such as UMTS, WiMAX, WiFi and BlueTooth; each of them can be attached to different Internet providers having different billing models and security levels. To allow mobile users to be always connected to the best available access network and maintain theirs connections when they switch from one network to another, several vertical handoff mechanisms have been recently proposed. Few of them deal properly with the cost in the decision process, which should be done at a per flow basis. Our current work focuses on an advanced middleware that allows, through a comprehensive profile management, the support of automatic interfaces configuration and per-flow interface selection taking into account preferences given by the terminal's owner and applications. As illustrative, we show how the proposed middleware allows cost effective management of a multi-interfaces terminals fleet through an easy to configure set of preferences and resources profiles.

https://hal.archives-ouvertes.fr/hal-02901288/document

Imed Lassoued

Papers

A Methodology for Evaluating Vertical Handoff Decision Mechanisms

Automatic multi-interface management through profile handling

Towards an Architecture for Mobility Management and Resource Control

A multi-task adaptive monitoring system combining different sampling primitives

Middleware for multi-interfaces management through profiles handling