lenges and opportunities for better geotargeting of mobile devices. These include the following:

• The current deployment of the long-term evolution (LTE)3 standard may provide a partial solution. With LTE, cellular IDs, which are used to determine if a tower is within the alerted area, are assigned to individual antennas on each tower, rather than the tower as a whole. This may allow for tighter sectioning of geographical regions within the tower’s signal.

• The use of GPS is a possibility for determining a mobile device’s location, but may pose a challenge if the GPS initiates a request to carrier networks to request location information. Davis noted that this may create congestion in the network and cause its failure. Furthermore, Davis reiterated that GPS inside buildings or on subways is a challenge, and commercial needs will drive the development of tools to allow this.

• Alerting systems may not need to do the geotargeting. A phone’s position may be determined by a combination of technologies, as described in previous sections, and then the phone can determine if an alert applies to its location.

• Another challenge is that geotargeting capabilities vary across carriers and devices and are an area of extreme competition between carriers. This creates barriers to discussions across organizations.

• The size of the message is probably the greatest hindrance. Davis explained that the biggest gain in encouraging appropriate public response, with the least impact on networks and devices, is the modest expansion of message information. An option to do this is to allow pagination of a message—that is, a series of messages that together provide the full alert text.


3 Long-term evolution is often marketed as 4G LTE.

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement