Javier Mulero Chaves

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).

Designing an efficient communications protocol to deliver alert messages to the population during crisis through GNSS

Multi-channel Early Warning Systems are currently used to warn the population at risk and reduce the impact of crisis. Nevertheless, satellite networks, which offer robust and reliable communication solutions during major disaster events, are not yet being fully considered for direct communication to the citizens. The paper will address solutions for the transmission of alert messages to warn/inform the population in risk during crisis through GNSS. The solution proposed is based on a protocol for alert messages that is compatible with the Common Alert Protocol (CAP), but lightweight in comparison with CAP, so that it can be applied over a variety of communication links, i.e. over different communication standards, even in very narrow band channels, such as Satellite-Based Augmentation System (SBAS). The paper will analyse the opportunities and implications of using GNSS to disseminate alert messages to the population and propose the principles for a flexible protocol that allows the translation of CAP messages (XML-based) into a very flexible and lightweight protocol for transmission in very narrow band channels.

Performance of database synchronization algorithms via satellite

In this paper, we examine different database synchronization/replication strategies and compare their suitability for satellite links in terms of latency and exchanged data volume. Earlier works have investigated the performance of these algorithms over terrestrial networks; however, the delay caused by a geostationary satellite has not been taken into account yet. A test-bed emulating a satellite link with database end nodes was used to compare different synchronization algorithms.

A Novel Protocol to Transmit Alert Messages during Crises over GNSS

Alert messages are usually encoded according to the CAP (Common Alerting Protocol) de-facto standard, which is usually translated into an appropriate XML schema for transport over HTTP. The large overhead introduced by XML penalizes the delivery of alert messages to final recipients because of the latency introduced in GNSS channels. To compensate this effect, this paper introduces a novel protocol actually translating the CAP format and providing a more efficient transport of alert messages.

Design aspects in multi-channel public warning systems

Abstract: In case of natural or man-made disasters it is essential to alert and provide meaningful warning information to enable individuals, communities and organisations at risk to prepare and to act appropriately to reduce the impact in terms of harm and loss. This statement involves: – some prior risk knowledge, that is the capability to understand what events or situations can be or become hazardous to specific communities; – the capability to detect and monitor those hazards in due time; – the capability to compile the relevant information in actionable messages and disseminate them to reach the individuals, communities and organizations at risk; – the preparedness of individuals, communities and organizations at risk to act upon reception of the warning information.

Public Warning Applications: Requirements and Examples

Abstract: Efficient emergency management requires authorities to be able to timely communicate with citizens at risk and provide them with the relevant information about risks and on-going emergencies as well as with the recommended protective actions. The current development of communication technologies together with the existence of newly developed personal receiver devices, such as smartphones, tablet PCs and navigators, makes it possible to provide authorities (alert message issuers) with end-to-end communication means towards citizens at risk (alert message recipients). Moreover, the processing power and storage capacity available in these receiver devices allow multi-channel public warning systems to make use of narrowband channels, such as the ones available in satellite navigation systems, moving the complexity of the system to the receiver devices.

TETRA Backhauling via Satellite: Improving Call Setup Times and Saving Bandwidth

In disaster management scenarios with seriously damaged, not existing, or saturated communication infrastructures satellite communications can be an ideal means to provide connectivity with unaffected remote terrestrial trunked radio (TETRA) core networks. However, the propagation delay imposed by the satellite link affects the signalling protocols. This paper discusses the suitability of using a satellite link for TETRA backhauling, introducing two different architectures. In order to cope with the signal delay of the satellite link, the paper proposes and analyzes a suitable solution based on the use of a performance enhancing proxy (PEP). Additionally, robust header compression (ROHC) is discussed as suitable technology to transmit TETRA voice via IP-based satellite networks.