Luis Veloso

MMC04-3: A Unifying Architecture for Publish-Subscribe Services in the Next Generation IP Networks

Next generation IP networks are envisioned to be heterogeneous, to provide a wide variety of services, and to support mobility of users with distinct requirements. Moreover, mobile communications are expected to expand from telephony to publish-subscribe services, such as real-time multimedia. With this goal, the University of Coimbra is working with DoCoMo Euro-Labs on a unifying control architecture for multimedia publish-subscribe services over an IP-based mobile system, where our proposal aims to control the quality of service and mobility across heterogeneous networks with no perceived service degradation to the users. This article highlights the requirements of a control architecture for publish-subscribe services, and presents our proposal, called QoS Architecture for Multi-user Mobile Multimedia (Q3M). The main components and functionality of the Q3M architecture are analysed from the user and network perspectives, and some simulation results concerning the analysis of the session setup times are presented.

Mobility management for multi-user sessions in next generation wireless systems

Mobility management and ubiquitous access for real-time multi-user sessions with Quality of Service (QoS) support are major requirements to the success of next generation wireless systems. In this context, Multi-User Session Control (MUSC) is proposed to allow fixed and mobile users to access multi-user sessions ubiquitously, while providing QoS mapping, QoS adaptation and connectivity control in heterogeneous environments with mobile receivers and static senders. By interacting with resource allocation controllers, MUSC allows the construction of QoS-aware distribution trees over networks with different QoS models and aims to keep sessions with an acceptable quality of experience in congestion periods. Furthermore, by interacting with mobility controllers, MUSC assures the session continuity with QoS and connectivity support. MUSC was evaluated in a simulation and in an experimental environment to analyze its convergence time as well as its efficiency in allowing seamless mobility and in keeping sessions with an acceptable quality level during handover.

QoS Mapping and Adaptation in Next Generation Networks

The end-to-end quality of service (QoS) control is one of the key factors to the success of next generation networks. Therefore, this paper presents a session-aware QoS mapping and adaptation mechanism that maps the session QoS requirements into the most suitable network service class across heterogeneous mobile networks as well as it adapts the session to the current network conditions. The proposed scheme allows mobile operators to keep network internals sufficiently opaque and to reduce operational costs by mapping and/or adapting sessions to groups of heterogeneous mobile users. Concurrently, the proposed scheme assures acceptable quality levels to on-going sessions, independently of the movement of users. In addition, an experimental evaluation in a QoS mobile multicast environment is presented

Q3M --- QoS Architecture for Multi-user Mobile Multimedia Sessions in 4G systems

Fourth generation systems (4G) will provide multimedia group communication sessions to multiple mobile users with distinct requirements. This way, it is expected the control of the quality level, connectivity and ubiquitous access for multi-user multimedia sessions across heterogeneous and mobile networks with seamless capability. This paper analyses the requirements of a control architecture to provide Quality of Service(QoS), connectivity and seamless handover management for multi-user sessions in 4G systems, and introduces the QoS Architecture for Multi-user Mobile Multimedia(Q3M) proposal. In addition, simulation results present the efficiency of this approach concerning the session setup time and packet losses during handover.

QoS mapping and adaptation control for multi-user sessions over heterogeneous wireless networks

The Quality of Service (QoS) support for multimedia multi-user sessions is essential to the success of fourth generation mobile networks. However, it requires the QoS control for those sessions independently of the movement of users, QoS model, and link capacity supported by wired and wireless networks in the end-to-end session path. This paper presents the Multi-user Session Control (MUSC) mechanism to provide QoS mapping and QoS adaptation of multi-user sessions over heterogeneous and mobile networks. The coordination of the QoS mapping and QoS adaptation controllers allows the adaptation of the session to the current network conditions and the dynamic selection of the most suitable network service class to map the session. The MUSC control is based on the session requirements, existing services class and their available bandwidth. Performance evaluation shows the impact of the MUSC proposal by analysing its convergence time, as well as the one-way delay and throughput of multi-user sessions in a QoS-aware mobile scenario.

Quality Level Control for Multi-User Sessions in Future Generation Networks

Real-time multimedia sessions are now present in our daily live experience, and will be among the most important applications in future generation networks. The distribution of those sessions, towards fixed and mobile users, with Quality of Experience (QoE) assurance is important to attract and keep customers, while increasing the profits of providers. This paper proposes the Quality Level Control for Multi-user Session (QUALITIS) approach to assure the quality level of sessions shared by multiple users (multi-users) in future generation networks. QUALITIS aims to keep sessions with an acceptable quality level and to avoid session blocking. The QUALITIS control is achieved by coordinating Quality of Service (QoS) mapping, QoS adaptation, resource allocation and mobility mechanisms. Performance evaluation was carried out based on simulation experiments and verified the QUALITIS impact on the users expectation and on the performance of the network.

Seamless Mobility of Users with QoS and Connectivity Support

The popularity of mobile devices associated with the growing interest in multi-user real-time sessions, such as IPTV, is foreseen as having a strong impact in the architecture of future heterogeneous networks. An important issue that needs to be solved concerns the capability to provide a seamless experience and an assured quality to the user independently of the connectivity technology supported by the mobile devices and offered by each network along the end-to- end path (e.g., unicast and/or multicast). In this paper, a solution to provide seamless mobility to users with connectivity and Quality of Service (QoS) control is presented. Seamless mobility is achieved through the use of buffers during movement and caches after the handover, and the quality level of the ongoing session is supported by using an end-to-end QoS mapping, QoS adaptation and connectivity control scheme. The obtained results confirm the capability of the proposal to avoid packet losses resulting from handover, and to improve the perceived quality of a received video sequence.

Mobility Support of Multi-User Services in Next Generation Wireless Systems

The substantial advancement and proliferation of wireless technologies leads to the need to efficiently manage user mobility. Furthermore, the simultaneously emerging of services like video-conference, radio and TV has emphasized the importance to deliver content to several simultaneous receivers. This way, one of the key challenges to deploy multi-user services in the next generation wireless systems is the support of seamless mobility of multi-user services. In this paper the functioning of the seamless mobility of users for media distribution services (SEMUD) proposal is presented. This mobility management technique possesses two operation modes. To provide seamless mobility the standard mode resorts on the collaboration between caches (located in the base stations) and buffers (located in the mobile nodes). The enhanced mode introduces mobility prediction and messages for context transfer between access routers. A performance analysis is given to corroborate the merits of the proposal.

Mobility Support for Multi-user Sessions over Heterogeneous Networks

It is expected that the next generation of networks will provide group communication services to mobile users, independently of the underlying Quality of Service (QoS) model, access and connectivity technologies, which may be different in each domain along the communication path. However, current mobility management schemes have limitations in terms of end-to-end QoS support and connectivity control for sessions crossing heterogeneous networks. This paper presents the Multi-user Session Control (MUSC) mechanism that controls the mobility of multiuser sessions while providing QoS mapping, QoS adaptation and connectivity support in heterogeneous environments with mobile receivers and static senders. Performance evaluation shows the MUSC efficiency to setup sessions inside and between access-networks, by analysing the packet delay and the percentage of packet losses during handovers.

Selective Mobility Support of Multi-User Services in Wireless Environments

Multicast mobility management is a challenging and unsolved task for the successful deployment of multi-user real-time multimedia services in next generation mobile networks. Therefore, a solution that constrains losses during handover and limits the service degradation perceived by users is needed. Moreover, the losses should be constrained taking in consideration the impact that different packets have in the quality of the multimedia session. In this paper, the seamless mobility of users for media distribution services (SEMUD) proposal takes in account this fact when constraining packet losses that result from the handover process. This leads to an augmented capability to provide seamless mobility for multi-user services. This ability is evaluated by comparing the quality of a received video sequence with and without taking into consideration the different importance that packets have in the quality of the sequence. The results attest for the quality improvement of the video sequence when the packets are handled taking in consideration their importance.