Report Says That SMS is Not Ideal for Emergency Communications
Published on: 17th September 2008
US trade group, 3G Americas has published a research report focusing on restrictions on the use of SMS as an emergency alert service. The use of text messaging or SMS has become ubiquitous and commonplace for recreational and business purposes. According to CTIA -The Wireless Association, text messaging has set new records in the United States, with 75 billion messages reported in the month of June 2008 alone -- about 2.5 billion messages a day. Accordingly, SMS messaging is now viewed by many as a reliable method of communication when all other means appear unavailable, and some third party companies are offering emergency notification services based on SMS.
''SMS is touted as being able to deliver critical information during disaster events, and such services have been purchased by universities and municipalities hoping to protect the general public,'' stated Patrick Traynor, Ph.D., Assistant Professor in the School of Computer Science at the Georgia Institute of Technology. ''Unfortunately, such systems typically will not work as advertised.''
The research conducted for the paper indicates that there are serious limitations in third party Emergency Alert Systems (EAS). In particular, because of the general architecture of CDMA, TDMA and GSM cellular networks, such systems will not be able to deliver a high volume of emergency messages in a short period of time. Through discussion, modeling and simulation, Traynor demonstrated in the paper that current systems not only cannot widely disseminate such messages quickly, but also that the additional traffic created by third party EAS solutions may disrupt other traffic such as voice communications, including that of emergency responders or the public to 9-1-1 services.
Traynor argues and demonstrates several reasons why EAS over SMS in current cellular systems is simply not feasible or recommended such as:
- Cellular networks are not designed to delivery emergency-scale traffic loads
- Cellular networks are not the Internet
- Targeting users in a specific location is extremely difficult
- There is no way to authenticate the source of messages, making fraudulent alerts easy to send
- SMS is not a real-time service
- Message delivery order is not always predictable
''As reported by the media, we had a reasonably good demonstration of wide-scale text messaging efforts by the Obama campaign recently,'' Traynor stated. ''However, even though the population participating in this campaign announcement was not necessarily as dense as a major disaster messaging effort, there were still significant message delivery issues reported similar to the ones described in my research paper.''
Traynor shows through a series of experiments, that even under optimal conditions, networks cannot meet the ten minute alert goal generally set forth by the public EAS charter. Moreover, it is further demonstrated that the extra text messaging traffic generated by third party EAS will cause congestion in the network and may potentially block the delivery of critical information, such as calls between emergency responders or the public to 9-1-1 services. The report concludes that it is critical that legislators, technologists and the general public understand the current limitations of these systems.
Solutions such as the efforts undertaken by the Commercial Mobile Service Alert Advisory Committee (CMSAAC) set up by the Federal Communications Commission (FCC) will allow cellular networks to take an active role during emergencies. The report suggests that through the creation of new standards such as Cell Broadcast, many of the problems created by the current ''point to point'' architecture can be avoided. In particular, by allowing each base station to act as a virtual megaphone, cellular networks will be able to rapidly distribute up to the moment emergency messages to all phones. While nearly all major cellular providers are actively working to design, test and deploy such systems, it will take time before this piece of our critical infrastructure can perform such tasks.
The white paper (pdf file, 31 pages) can be downloaded from the 3G Americas website.