Research

Currently the Telecommunication Group has one major area of research and two emerging areas.

In the main area of research we are interested on architectures and protocols for telecommunication networks. We focus our attention on middleware issues going from the MAC (Medium Access Control) sublayer until the Application Layer. We are currently performing some work

• on mobile systems beyond 3G both in terms of inter-system handovers and handling of the different radio access networks by the applications;

• on middleware systems that can cope with millions of entities (users, servers, etc.); and

• on ad-hoc networks (specially in algorithms that can run on pure ad-hoc or more structured networks).

Our approaches start most of the times on the proposal of new architectures to handle the problems and are mostly based on simulations to prove the features of the solutions.

Main Scientific Areas and Interests

Wireless Networks (contact persons: Paulo Pinto)

 Interconnection between heterogeneous wireless systems (systems beyond 3G). The work focuses on WLAN integration on 3G cellular systems using a novel approach for the interworking architecture, called core-level approach, and seamless continuity of PS-services.

This work is pursuing into two directions:

a.        session and mobility supporting services at the core network (at both service and control planes) to enable the construction of applications that can take advantage of the intermittent connections to WLAN having the 3G cellular network as a ubiquitous network to maintain state coherence.

b.       quality of service in order to support continuity of real-time services;

Peer-to-peer and AdHoc-Networks (contact persons: Luis Bernardo)

 Middleware for ad hoc networks. The work focuses on self-organizing and self-healing peer-to-peer services optimized for running on pure ad hoc and meshed networks. This work is pursuing in two directions:

a)       information retrieval at (possibly dense) ad hoc networks in the presence of mobile embedded nodes (that may run sensor data driven protocols) create special robustness requirements, which can not be handled solely by the routing and MAC protocols.

b)       grid support for ad hoc networks, with improved adaptability, context awareness, and autonomy, through massive middleware service distribution through the nodes. Envisioned services include QoS support, process deployment, and node self-configuration.

Middleware systems (contact persons: Paulo Pinto or Luis Bernardo)

 Scale-free grid middleware systems. The work focuses on the deployment of self-organized application servers, capable of reacting autonomously to harsh environment conditions (load peaks, QoS drops, etc.) by adapting the number and location of the servers, and maintaining a state of end-to-end QoS with their clients. The location server itself was object of the research as a distributed application. The work is pursuing in two directions:

a)       new application-server deployment algorithms.

b)       location service algorithms (management of information, etc) using a peer-to-peer approach.

Emerging Scientific Areas

Propagation and Radiation (contact persons: Isabel Ventim Neves)

Research in the area of guided propagation in dielectric structures of cylindrical geometry made of non-homogeneous materials or anisotropic.

Signal Processing in Telecommunications (contact persons: Paulo Montezuma)

The main research area is focused on the physical layer, covering aspects as codification, mainly convolucional, trellis and turbo codes, as well concatenated codes. Future topic areas are spread spectrum techniques, for Ultra wideband systems and wireless systems.