Josephine Antoniou

Access network synthesis game in next generation networks

In next generation communication networks, multiple access networks will coexist on a common service platform. In cases where network resource planning indicates that individual access network resources are insufficient to meet service demands, these networks can cooperate and combine their resources to form a unified network that satisfies these demands. We introduce and study the Network Synthesis game, in which individual access networks with insufficient resources form coalitions in order to satisfy service demands. The formation of stable coalitions in the core of the game is investigated, in both cases where payoffs are transferable or are attributed in proportion to the contribution of each member of the coalition. We also consider an alternative payoff allocation approach, according to the value of the well-known Shapley-Shubik, Banzhaf and Holler-Packel power indices, which represent the relative power each player has in the formation of coalitions. Using the knowledge attained from the coalition game analysis, we propose a new power index, called Popularity Power Index, which is based on the number of stable coalitions an access network would participate in if payoffs were assigned in a fair manner.

Supporting Context-Aware Multiparty Sessions in Heterogeneous Mobile Networks

The article addresses context-aware, adaptive multiparty sessions in a heterogeneous system through such elements as adaptivity and context-awareness. The effective usage of context information can lead to context-aware content casting, especially context-aware, adaptive multicasting. Therefore, regarding the multicast service, the key functionality of an enhanced Session Management is to motivate the creation of user subgroups, subsets of the same content group based on network, user and environment context to the extent that these are necessary for efficiency. Their characteristics in the form of content descriptions are communicated to the media delivery to obtain the appropriate content for each session. The article presents in detail the initiation, modification, termination and mobility of an adaptive, context-aware multicast session.

Simulating soft handover and power control for enhanced UMTS

In this paper we present a soft handover algorithm for wide band CDMA based E-UMTS networks and the associated power control algorithm. The handover and power control algorithms have been developed and implemented in the framework of a system level E-UMTS simulator developed under the 1ST SEACORN project. The paper provides a background on handover design techniques and explains the handover implementation. The soft handover algorithm has been modeled using the guidelines provided in the standards and the literature for W-CDMA intra-frequency handovers. The combination of established handover techniques with enhanced UMTS is a novelty feature of this paper and provides a reference for further performance comparison

Context-aware control for personalized multiparty sessions in mobile multihomed systems

Telecommunication and Internet services are constantly subject to changes, seeking customers satisfaction. Enriching services with innovative approaches such as context-aware, mobile, adaptable and interactive mechanisms, enables users to experience personalized services seamlessly across different technologies. Aiming at evolving mobile multimedia multicasting to exploit the increasing integration of mobile devices with our everyday physical world, a context-aware multiparty delivery needs to research into two important frameworks: context detection and distribution and context-aware multiparty networking, encompassing adaptations at the session, transport, and network layers. The paper diverges into the second by focusing on the user perceived Quality of Experience and efficient network support of real-time group communications, allowing dynamic adaptation of the multiparty delivery, group communications optimization and maximization of group members overall satisfaction.

A discrete event based simulation environment for enhanced UMTS 3 rd generation networks

This paper presents a new system level simulator that has been developed to evaluate E-UMTS (Enhanced Universal Mobile Telecommunication Systems) 3G Networks. The article describes how the simulator supports different mobility, propagation, and traffic generation models and how this simulation framework can be used to evaluate new protocols, algorithms, or resource management mechanisms. Specific models and performance details for a sample scenario of a business city center are also provided.

Architecture for context-aware multiparty delivery in mobile heterogeneous networks

Future networks are envisioned to satisfy the user needs and improve their quality of experience. This requires the networks to support context-aware information, where context of the user, session, network and environment will greatly influence the way the session is delivered: new approaches are required to deal with the overall context information and network reaction to constantly context changes. This paper presents a context-aware architecture that provides delivery of multiparty services in heterogeneous and mobile environments. The architecture, its elements and functionalities are described through a specific application to a context-driven use case scenario. We show that this architecture is able to provide personalized and multiparty services to the users, addressing their characteristics and preferences, and optimizing network support while mobility and heterogeneous environments are in place.

Power counting for optimized capacity in MBMS enabled UTRAN

MBMS bearer services can be provided in each cell by either point-to-point or point-to-multipoint transmission mode but for efficiency a decision has to be made between the two approaches. Initially, the fundamental criterion used to make this decision was the number of MBMS users in a cell (UE counting). In this paper we extend our previous work, which proposed the power transmitted by the base station (BS) as the channel switching criterion (power counting). We evaluate our approach and illustrate its capability to dynamically adapt to continuously varying cell conditions by selecting the transmission mode in a more efficient way, preserving in this way the networkpsilas resources. At the same time we demonstrate the limitations of the conventional approach, in terms of radio resource efficiency. We show that by having the power used by the BS as the limiting factor we achieve optimized capacity during the transmission of MBMS bearer services in UTRAN.

Context Aware Multiparty Session Support for Adaptive Multicasting in Heterogeneous Mobile Networks

The paper addresses the issue of achieving context-aware, adaptive multiparty sessions in a heterogeneous system by illustrating how to add elements of adaptivity and context-awareness to the session management functionality of such systems. The effective usage of situation/context information can lead to context-aware content casting, especially context-aware, adaptive multicasting. Therefore, regarding the multicast service, the key functionality of the enhanced session management is to create network subgroups based on network information as well as general user and environment context information to the extent that these are considered necessary for forming network-efficient groups, and in turn communicating the characteristics of these subgroups in the form of content stream descriptions to the media delivery function for obtaining the appropriate content for each subgroup.

Context-Aware Self-optimization in Multiparty Converged Mobile Environments

The increase of networking complexity requires the design of new performance optimization schemes for delivering different types of sessions to users under different conditions. In this scope, special attention is given to multi-homed environments, where mobile devices cross areas with overlapping access technologies (Wi-Fi, 3G, WiMax). In such scenario, efficient multiparty delivery depends upon the grouping operation (creation of a set of users to receive a given session), which must be done based on several parameters. We propose sub-grouping of content-based service groups, so that the same service session can be delivered using different codings of the same content, to adapt to the current network, users, session and environment context. The context-aware information is used to improve the sub-grouping process. This paper aims to describe these sub-grouping techniques, in particular how they improve network performance and user experience in the future Internet, in the scope of cognitive autonomic networks.

Ran Selection for Converged Networks Supporting IMS Signalling and MBMS Service

Future communication networks are envisioned to be based upon a common, flexible and scalable convergence platform, where different access networks, different terminals and different services can coexist. The new user capabilities spawn a demand for Always Best Connectivity (ABC), i.e. that a user can always have the best possible connection regardless of place and time. This brings forth a new communication paradigm, which is user-centric, i.e. the user is no longer bound to only one access network but can choose the best available access network to satisfy a specific service request. The IP multimedia subsystem (IMS) is the technology promoted to enable this ubiquitous converged network. This paper considers the selection of access network, specifically for multicast/broadcast users and proposes a novel RAN selection scheme implemented using IMS signalling.