Matteo Berioli

On ant routing algorithms in ad hoc networks with critical connectivity

This paper shows a novel self-organizing approach for routing datagrams in ad hoc networks, called Distributed Ant Routing (DAR). This approach belongs to the class of routing algorithms inspired by the behavior of the ant colonies in locating and storing food. The effectiveness of the heuristic algorithm is supported by mathematical proofs and demonstrated by a comparison with the well-known Ad hoc On Demand Distance Vector (AODV) algorithm. The differences and the similarities of the two algorithms have been highlighted. Results obtained by a theoretical analysis and a simulation campaign show that DAR allows obtaining some important advantages that makes it a valuable candidate to operate in ad hoc networks and the same method helps in the selection of the algorithm parameters. Since the approach aims at minimizing complexity in the nodes at the expenses of the optimality of the solution, it results to be particularly suitable in environments where fast communication establishment and minimum signalling overhead are requested. These requirements are typical of ad hoc networks with critical connectivity, as described in the paper. Thus the performance of the proposed algorithm are shown in ad hoc networks with critical connectivity and compared to some existing ad hoc routing algorithms.

MPLS-based satellite constellation networks

Nongeostationary satellite constellations with intersatellite links are a challenge for networking due to their continuously changing topology. In order to make maximal use of the networks capacities, special attention has to be paid to routing and traffic engineering. Multiprotocol label switching (MPLS) as underlying protocol is an interesting candidate for this task since it offers many possibilities to exert influence on traffic flows and supports todays dominating Internet protocol traffic very well. This paper describes a general MPLS-based networking concept for satellite networks and discusses different scenarios considering the particularities and constraints of the dynamic topology. Functional elements of MPLS like ingress, egress, or core routers have to be mapped onto the physical entities of the network and prerequisites for traffic engineering are discussed. Routing and rerouting of paths is of key interest since this affects route computation effort and routing performance. Thus, an analytical estimation of routing effort is deduced and numerical and simulation results are presented.

Aerospace Communications for Emergency Applications

In this paper, the current trends and the most recent advancements in the utilization of aerospace communications for emergency rescue applications will be discussed, with a special focus on the integration of the aerospace segment with terrestrial backbones and ad hoc terrestrial networks for both data connections and assisted localization (information about position is essential in emergency relief).

Instantly decodable network coding protocols with unequal error protection

This work aims at introducing two novel packet retransmission techniques for reliable multicast in the framework of Instantly Decodable Network Coding (IDNC). These methods are suitable for order- and delay-sensitive applications, where some information is of high importance for an earlier gain at the receivers side. We introduce hence an Unequal Error Protection (UEP) scheme, showing by simulations that the Quality of Experience (QoE) for the end-users is improved even without complex encoding and decoding.

WISECOM: A rapidly deployable satellite backhauling system for emergency situations

This paper presents the detailed architecture of the WISECOM system, which can quickly re-establish and provide telecommunication services after a disaster by integrating terrestrial mobile radio networks, such as GSM, WiFi, WiMAX and TETRA, with satellite technologies. The system aims to be a useful tool to be deployed in the early hours after a disaster event, for both the victims and the rescue services who will be able to communicate in a reliable and robust way, improving the coordination of the different teams and reducing the time needed to provide victims with the proper treatment. The paper presents in detail the different services provided by the system taking into account its two different versions, based on two different satellite technologies, Inmarsat BGAN and DVB-RCS. Together with the presentation of the system capabilities, a business model is also proposed. Thereafter, the architecture of the general system and the demonstrators that have been developed are detailed, according to the two versions of the system. The work also presents the outcomes of the tests conducted with a prototype of the system, and of the final project demonstration, which was held in Germany in May 2008 with the involvement of real end-users (fire brigades and civil protection authorities).

Emergency Communications over Satellite: the WISECOM Approach

This paper presents the overall architecture of the WISECOM system, which can quickly re-establish and provide telecommunication services after a disaster. The architecture is explained and it is described together with a role model, which adapts to the system. The work tries to map the existing complex interactions taking place nowadays in an emergency situation to a sensible architecture, which can accommodate all needed actors and roles, and which can exploit, at the same time, the newest wireless technologies.

Integrated GSM/WiFi Backhauling over Satellite: Flexible Solution for Emergency Communications

This paper presents the development of a compact, ruggedized satellite terminal, to be used for communications in emergency situation. The terminal provides GSM coverage in disaster area, where existing communication infrastructure is destroyed or overloaded. It uses GSM backhauling over satellite to transport GSM signalling and data traffic to the core GSM network infrastructure in the disaster-safe area. Additionally, basic data services such as HTTP Web browsing and email are also provided via WiFi access. Issues related to the terminal design and the tests that have been undertaken are presented in the paper.

Integrating satellite and terrestrial technologies for emergency communications: the WISECOM project

In this paper, the main concepts of the Wireless Infrastructure over Satellite for Emergency COMmunications project (WISECOM) are presented. These concepts rely upon the idea of a light and rapidly deployable system that can be autonomously used in remote areas where telecommunication networks have broken down to provide access to emergency telecommunication services using a large set of wide-spread telecommunication technologies such as GSM, UMTS, WiFi, WiMAX, and TETRA and a satellite back-hauling link. In the paper, a detailed description of the whole WISECOM system is provided, with emphasis on the WISECOM Access Terminal, the unit deployed on the disaster area and interfacing the selected satellite system to different wireless local access technologies. Then, three relevant and realistic examples of configuration of the WISECOM system (GSM, UMTS and TETRA over satellite) are detailed.

Broadband Satellite Multimedia

The broadband satellite multimedia (BSM) architecture standardised by ETSI defines a satellite independent service access point (SI-SAP) interface layer that separates the satellite independent features of the upper layers from the satellite dependant features of the lower layers, and provides a mechanism to carry IP-based protocols over these satellite dependent lower layers. This enables interoperability at the IP layer between satellite systems of different physical and link layers technologies that fully comply with the SI-SAP concept. This study reviews past and current standardisation activities including the BSM quality of service (QoS) architecture, security architecture, network management that have been carried out by the ETSI Technical Committee-Satellite Earth Stations and Systems (TC-SES)/BSM working group and looking into the future to extend current SI-SAP functions that can enhance existing QoS provision and security management capabilities as well as proposing a mobility management architecture that complies with the IEEE 802.21 media independent handover framework to support BSM mobility and to allow integration of satellite networks with fixed and mobile network infrastructures. A service-based network management architecture is also proposed to allow management flexibility and integration of business and operation support functions, paving the way for satellite integration into the Internet of the future.

Sliding window-based Contention Resolution Diversity Slotted ALOHA

Contention Resolution Diversity Slotted ALOHA (CRDSA) and its burst degree optimizations (CRDSA++, IRSA) make use of MAC burst repetitions and Interference Cancellation (IC) making possible to reach throughput values as high as T ≃ 0.8 in practical implementations, whereas for the traditional slotted ALOHA T ≃ 0.37. However, these new techniques introduce a frame-based access to the channel that limits the performance in terms of throughput and packet delivery delay. In this paper, a new technique named Sliding Window CRDSA (SW-CRDSA) and its counterpart for irregular repetitions (SW-IRSA) are introduced in order to exploit the advantages of MAC burst repetition and Interference Cancellation (IC) with an unframed access scheme. Numerical results are also provided in order to validate the statement of better performance.