A Simulation Analysis of CMAS Performance

The Commercial Mobile Alert System (CMAS) was established to allow wireless service providers to send geographically targeted emergency alerts to their subscribers. Although CMAS became operational in various parts of the country, there aren't any studies known to the authors that investigated performance of CMAS either in normal conditions of network connectivity, or, more importantly, in certain extreme conditions that can be expected during a major disaster. CMAS uses the Internet for connectivity between main components of the system, and therefore it would be directly affected by potential communication delay or loss of connectivity issues in the aftermath of a disaster. Furthermore, the reception of CMAS alerts by cellular devices is affected by phone call volume, which can also increase following a disaster.

In this paper we describe a computer model of CMAS and present a simulation analysis of the system to characterize its performance under various conditions, including increased network load, high Internet latency, and high phone call volume. Our results show that while CMAS can have adequate performance for some types of emergencies, the end-to-end latency can become too large for highly delay-sensitive alerts such as earthquake and tornado warnings under certain extreme conditions.