Johnny Choque

Optimum Selection of Access Networks Within Heterogeneous Wireless Environments Based on Linear Programming Techniques

In this work we analyze the possibilities which are brought about by the use of linear programming techniques in the framework of access selection procedures within heterogeneous wireless network environments. We present a tool which has been designed and implemented (based on the GLPK package) to tackle this problem. This tool can be used to retrieve the optimum assignment of access elements of a particular network deployment. To fulfil this goal, we introduce a flexible cost (utility) function, which allows modulating the relevance given to the different aspects which could be taken into consideration while deciding the access alternative to be used: connection with a preferred operator, minimizing the number of handovers, or selecting the link with the best quality, amongst others. Afterwards, the tool is used to study a set of access selection strategies, so as to establish the combination of parameters which might lead to optimum performances.

Performance analysis of HIP-based mobility and triggering

Ambient Networks concentrates on the co-operation of heterogeneous networks over multiple domains and accesses. One of the main goals of the project is the integration of developed concepts for validation purposes. This paper presents a performance analysis on the integration of mobility triggering and Host Identity Protocol (HIP) based mobility on the Ambient Networks/FreeBSD platform. The scalability of triggering and handover latency has been focused on in terms of different mobility triggers and access technologies. The results enable identification of the largest delay components, which have been analyzed.

An experimental study of Snoop TCP performance over the IEEE 802.11b WLAN

Our aim is to compare, from an experimental point of view, the TCP performance achieved using TCP Reno with the SACK (selective acknowledgment) implementation, and that obtained using the Snoop TCP proxy-based approach over an IEEE 802.11b wireless LAN. This study has been carried out in the context of the WINE (wireless Internet networks) project corresponding to the 5th framework of the European IST programme, addressed to enhance the performance of the TCP-UDP/IP protocol stack over wireless infrastructures such as IEEE 802.11, Bluetooth and HIPERLAN/2. The objective of this project is to develop a performance enhancing proxy (PEP), named the wireless adaptation layer (WAL), targeted at Internet protocols when they operate over wireless shared access LANs. The Snoop agent has been implemented as a module belonging to this layer.

Co-creating the cities of the future

In recent years, the evolution of urban environments, jointly with the progress of the Information and Communication sector, have enabled the rapid adoption of new solutions that contribute to the growth in popularity of Smart Cities. Currently, the majority of the world population lives in cities encouraging different stakeholders within these innovative ecosystems to seek new solutions guaranteeing the sustainability and efficiency of such complex environments. In this work, it is discussed how the experimentation with IoT technologies and other data sources form the cities can be utilized to co-create in the OrganiCity project, where key actors like citizens, researchers and other stakeholders shape smart city services and applications in a collaborative fashion. Furthermore, a novel architecture is proposed that enables this organic growth of the future cities, facilitating the experimentation that tailors the adoption of new technologies and services for a better quality of life, as well as agile and dynamic mechanisms for managing cities. In this work, the different components and enablers of the OrganiCity platform are presented and discussed in detail and include, among others, a portal to manage the experiment life cycle, an Urban Data Observatory to explore data assets, and an annotations component to indicate quality of data, with a particular focus on the city-scale opportunistic data collection service operating as an alternative to traditional communications.

Paving the way for future mobility mechanisms: a testbed for triggering & moving network support

Forthcoming wireless communication systems, well represented by the term beyond 3G, are likely to impose some new requirements that go beyond the traditional view on todays networking paradigm. In particular, mobility procedures will no longer be restricted to the change of the point of attachment to the network. The work presented in this paper aims at proving, following a fully experimental approach, the feasibility of some architectural components of a mobility control space, which has been designed so the context of the ambient networks project. Especially, in this study we focused on and successfully realized two concepts, a facility for triggering mobility events and support for moving networks

An integrated Ambient Networks prototype

Ambient networks (AN) project focuses on the convergence of heterogeneous networks over different domains. The aim (among others) is to facilitate co-operation, mobility support and multi-access between networks and terminals. One of the most important goals is to integrate the different AN-concepts together for validation. This paper presents an integrated prototype as proof-of-concepts, which can be used for demonstration purposes. In particular the prototype has integrated host identity protocol (HlP)-based mobility, HIP network mobility, simultaneous multi-access (SIMA) policies, generic link layer (GLL), mobility triggering (TRG) and basic composition concepts within the Ambient Control Space framework.

On the Relay-Based Coverage Extension for Non-Conventional Multi-Hop Wireless Networks

Due to the rapid growth of personal communications, it is now believed that multi-hop topologies will certainly play a key role in forthcoming wireless communications scenarios. Amongst other aspects, they will facilitate the appearance of new business models, allowing e.g. the possibility for operators to extend their services on a cost effective way. In this sense, an end-user may act as a relaying node, offering other end-users the possibility to connect to a base station (or access point) even if these were not able to do it directly (because e.g. they were not within the coverage area or they were not costumers of that operator). This paper analyzes one of the benefits brought about by multi-hop accesses, particularly the coverage extension that could be enabled by these approaches, by performing both an analytical and a simulation study. We analyze the outage probability over different network deployments, increasing the number of hops that a user might employ to reach an access point.

Coverage extension by means of non-conventional multi-hop communications

This paper analyzes the benefits that can be obtained by using opportunistic multi-hop extensions in terms of coverage extension of traditional network deployments. We assume that there are some devices acting as relaying entities, so as to allow others reaching an Access Element, in those situations in which a direct connection is not possible. Two different network deployments are used for this analysis: in the first one, an a priori planning is not assumed and, therefore, the Access Elements are randomly deployed, thus leading to a rather poor connectivity; on the other hand, in the second case, the Access Elements are placed according to an array deployment, thus maximizing the covered area. The paper finds analytical expressions for the probability of a user to be disconnected, i.e. she is not able to reach an Access Element, or the outage probability, for both scenarios, when either one or two hop paths can be used. These results are assessed, first, and complemented later, by means of an extensive simulation-based analysis, which brings about the possibility of extending the results when more than two hops are considered. The results provide helpful insights for aiding network dimensioning processes, since they allow establishing sensible bounds on the maximum number of hops which should be used to connect to the network; in the two complementary deployments which are used throughout the paper, there was not much additional benefit for paths longer than three/four hops, regardless of the probability for a user terminal to behave as a forwarding node.

Towards a Multi-Access Prototype in Ambient Networks

In a network environment where the presence of heterogeneous wireless accesses is becoming more and more likely, it becomes critical to achieve an efficient management of the available radio resources. This is one of the main objectives which are being pursued by the ambient networks project. One of the main distinctive aspects of this work is that it is going further of state of the art, since the goal is to assess the feasibility of the proposed solution by means of a prototype based on existing (off-the-shelf) devices and technologies. In this paper we describe the main characteristics of the multi radio access architecture which is being specified in the framework of the aforementioned project, encompassing two main entities: the multi radio resource management and the Generic Link Layer. Furthermore, we also describe the interfaces that have been specified to be used between them and we discuss how the architecture is mapped onto a software implementation.

Ambient networks in practice instant media services for users on the move

This demonstration exhibits the novel concepts of autonomic network composition and adaptive media delivery which have been developed as part of the EU framework 6 project ambient networks. A realistic use case serves as a demonstration scenario to illustrate how these core features of an ambient network work together in practice, and how they can contribute to improve the end users experience in a dynamic and mobile network environment. The scenario is based around a video-on-demand (VoD) streaming service. It involves a service provider, network operator and mobile user. The selected scenario highlights some essential features of ambient networks: plug and play network organization, customizable and adaptable transport overlays, and smart media routing