Portable satellite base stations bolster disaster response
August 01, 2012 | Ebrahim Busheri, Tim Phipps | 222903078
Terrestrial communication systems typically are knocked out by disasters, or overloaded following them. Here we review how satellite systems have overcome these problems for events such as 9/11 and last year’s Haitian earthquake, and how recent advances in portable base station design will give significantly greater access to communication networks in an emergency.
Image 1: Destruction in Port-au-Prince, Haiti, following the 2010 earthquake.
Recent years have seen several significant national disasters around the globe, including the Tōhoku earthquake and tsunami, which led to over 15,000 deaths and triggered a level seven meltdown at the Fukushima nuclear plant; and the 2010 Haiti Earthquake, which caused over 300,000 deaths. These joined a host of similar disasters from a landslide in Uganda, to an earthquake in Chile, and severe flooding in both Australia and Thailand.
According to a 2005 New York University report, one of the key preventable losses of life comes from the failure of telecommunications infrastructure.  These failures cause "…delays and errors in emergency response and disaster relief efforts,” say the authors, noting that "despite the increasing reliability and resiliency of modern telecommunications networks to physical damage, the risk associated with communications failures remains serious because of growing dependence upon these tools in emergency operations."
Published five months after the Indian Ocean tsunami and four months before hurricane Katrina, the report also stated: "The Indian Ocean tsunami of December 2004 highlighted the human cost of communications breakdowns during disasters. While seismic monitoring stations throughout the world detected the massive sub-sea earthquake that triggered the tsunami, a lack of procedures for communicating these warnings to governments and inadequate infrastructure in the regions at risk delayed the transmission of warnings. Yet, based on the successful evacuation of the handful of communities that did receive adequate warning through unofficial channels, it is clear that better communications could have saved tens or hundreds of thousands of lives."
Even when a network isn’t damaged in a disaster, problems can arise purely through overload. People call to reassure friends and family that they are all right, generating massive spikes in traffic. Examples of this include the September 11th attacks on the World Trade Center in New York, the 2007 Minnesota bridge collapse, and the 2010 Chilean earthquake.
It is clear that our daily reliance on communication systems—and with it the ability to, under normal circumstances, see exactly what is happening almost anywhere at any point in time—makes us increasingly aware of the human toll of a disaster.
Communicating in disaster
Currently, the only failsafe communications technology is satellite telephony, which uses either geostationary (positioned at 35,000 km) or low-Earth-orbit (positioned at 640 to 1120 km) satellites instead of terrestrial cell base stations. Satellite communication networks are unaffected by natural disasters. Using a network of 66 low-Earth-orbit satellites, it is possible to cover the entire planet, and one commercial satellite system (Iridium) offers 100% global coverage. In contrast, less than 1% of the Earth’s surface has mobile phone coverage.
With satellite systems being unaffected by disasters here on Earth, the simple solution for improving disaster recovery communications is to increase the number of handsets available for emergency and aid services. The problem is that the cost of broadband global area network (BGAN) terminals (see figure 2) makes wide scale deployment impractical for emergency services & aid charities. The challenge is finding a way to make it financially viable on a larger scale for civil support workers.
Figure 2: Broadband global area network (BGAN) satellite phones are reliable but too expensive for wide-scale deployment.
Portable base stations
Increasing levels of technology integration allow us to build smaller and smaller base stations that enable temporary networks to be established on the fly. With these networks, aid workers can now use normal cellular handsets to communicate. Local infrastructure might be destroyed but these base stations allow both local emergency services and traveling aid relief organizations to coordinate efforts by inexpensive, often donated, handsets. Key to delivering this is both portability and flexibility.
Figure 3: Powered by the LimeLMS6002D flexible radio transceiver, the 9-cm x 8-cm Sidewinder base station reference design from Cambridge Consultants can be powered from a battery or from an adaptor that plugs into the socket of a vehicle cigarette lighter.
An ideal portable base station consists of a software defined radio that can be configured to connect any handset within a few hundred meters. A flexible radio transceiver enables the user to operate across a broad band of carrier frequencies, allowing handsets from the widest possible variety of countries and years to be used. The Sidewinder’s range of 300 MHz to 3.8 GHz, with a 28-MHz channel bandwidth allows it to support a Nokia 2110 from 1995, for example. Such systems can alter standards and frequency bands to work with the available handsets and avoid interference from other wireless networks.
With these types of units, local communication networks could be established within minutes of emergency services and relief teams entering the disaster zone, enabling better management of search and medical assistance teams. By combining the base station with a satellite network back haul, emergency services could also rapidly deploy a network to remote teams and headquarters to optimize the aid effort.
From Haitian earthquakes to Ugandan landslides, disasters often strike in the most inconvenient of locations. However difficult the situation, emergency service workers need ubiquitous communications. Satellite communications seems like a good fit but the costs is prohibitive. By using technological advances to create affordable, portable, low-power, and flexible cellular base stations, coupled with a low scale satellite back-haul, we can sidestep one of the major preventable causes for loss of life—the failure of telecommunications infrastructure.
1. A. Townsend and M. Moss, "Telecommunications Infrastructure In Disasters," Robert F. Wagner Graduate School of Public Service, New York University (2005).
About the authors
Tim Phipps works in wireless business development for Cambridge Consultants. Throughout his career he has been involved in the development of leading-edge wireless technologies including cellular, Wi-Fi and Bluetooth.
Ebrahim Bushehri has over 15 years in directing and managing IC design teams within the wireless communication market. Prior to founding Lime Microsystems, Ebrahim was with Middlesex University Microelectronics Centre (MUMEC), collaborating with top tier organizations such as Nokia, Qinetiq (formerly Defence Evaluation Research Agency) and Fraunhofer IAF.
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