Positioning of IP telephones

• Main Author: Anna, Ljungström
• Format: Others
• Language: English
• Published: KTH, Kommunikationsnät 2011
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-53491

This report considers the problems with positioning of emergency telephone calls. Emergency calls to the emergency number “112” answered by the emergency service in Sweden cannot always be positioned. That is, it cannot be decided where the call is coming from. The problem with positing of emergency calls is mainly caused by emergency calls coming from Internet Protocol (IP) telephones. Since the use of IP telephones are increasing the number of emergency calls coming from IP telephones will increase. For the emergency service to provide a secure and reliable service to the public it is crucial that all emergency calls can be positioned correctly. The report explains how emergency calls are connected towards the emergency service in Sweden, from the different types of telephones that support emergency calls. For the traditional fixed land line all emergency calls can be positioned, when using a mobile telephone 90% of the emergency calls can be positioned. The IP telephones can be divided into two categories, fixed and nomadic. When a fixed IP telephone is used the emergency call can always be positioned correctly, the problem occurs when a nomadic IP telephone is used. Interviews have been held with the four largest IP telephone operators to get their views of the problem and whether they have an opinion on how to solve the problem. Practical tests have been performed to show the problem and when it occurs. To solve the problem with positioning of emergency calls coming from IP telephones an international standard must be set. New features needs to be implemented in the networks so that the calls coming from IP telephones can be positioned and utilize positioning features such as GPS. A lot of work still remains before an international standard can be set.