Rapport LITH-ITN-EX--07/021--SE Support for Cell Broadcast as Global Emergency Alert System Karin Axelsson Cynthia Novak 2007-06-19 Department of Science and Technology Institutionen för teknik och naturvetenskap Linköpings universitet Linköpings universitet SE-601 74 Norrköping, Sweden 601 74 Norrköping LITH-ITN-EX--07/021--SE Support for Cell Broadcast as Global Emergency Alert System Examensarbete utfört i telekommunikation vid Linköpings Tekniska Högskola, Campus Norrköping Karin Axelsson Cynthia Novak Handledare David Gundlegård Examinator David Gundlegård Norrköping 2007-06-19 Datum Avdelning, Institution Date Division, Department Institutionen för teknik och naturvetenskap 2007-06-19 Department of Science and Technology Språk Rapporttyp ISBN Language Report category _____________________________________________________ Svenska/Swedish Examensarbete ISRN LITH-ITN-EX--07/021--SE x Engelska/English B-uppsats _________________________________________________________________ C-uppsats Serietitel och serienummer ISSN D-uppsats Title of series, numbering ___________________________________ _ ________________ x _ ________________10 p URL för elektronisk version Titel Title Support for Cell Broadcast as Global Emergency Alert System Författare Author Karin Axelsson, Cynthia Novak Sammanfattning Abstract Cell Broadcast (CB) is a possible technical realisation of a global emergency alert system. It is a technique used for sending short text messages to all mobile stations (MSs) in a defined geographical area. An potential effect of using CB is the increase in battery consumption of the MS due to the fact that an extra channel has to be used to make the service available even when the network is otherwise congested. Another part of the service which leads to a potential problem is making CB messages available in different languages. Investigating these problems is the objective of this thesis and the studies it includes. During the first part of the thesis, we measured the battery consumption of MSs in different modes of operation in order to analyse how CB affects the amount of current drained. The tests showed that battery consumption increased only slightly when CB messages were being received at the MS. Although some of the results can be, and are, discussed, we believe that CB would have a small effect on the power consumption of an MS, particularly in a context where it would be used for emergency warning messages only. This mentioned, it would however be wishful to confirm the conclusions further through the realisation of long-term testing. The second part of the thesis deals with the investigation of the MSs support for CB messages with different coding schemes. Based on the investigations result, we have come to the conclusion that in the long term the usage of different coding schemes on the same channel is preferred. However, the usage of one, global, emergency channel is hard to realise since that requires a standardisation between all countries. In our opinion this may be achieved first in the long run and until then, the usage of separate channels seems to be necessary. Nyckelord Keyword Cell Broadcast, mobile communications systems, battery power consumption, global warning system, coding schemes, GSM 7 bits, UCS2, language support investigation Upphovsrätt Detta dokument hålls tillgängligt på Internet – eller dess framtida ersättare – under en längre tid från publiceringsdatum under förutsättning att inga extra- ordinära omständigheter uppstår. Tillgång till dokumentet innebär tillstånd för var och en att läsa, ladda ner, skriva ut enstaka kopior för enskilt bruk och att använda det oförändrat för ickekommersiell forskning och för undervisning. Överföring av upphovsrätten vid en senare tidpunkt kan inte upphäva detta tillstånd. All annan användning av dokumentet kräver upphovsmannens medgivande. För att garantera äktheten, säkerheten och tillgängligheten finns det lösningar av teknisk och administrativ art. 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All other uses of the document are conditional on the consent of the copyright owner. The publisher has taken technical and administrative measures to assure authenticity, security and accessibility. According to intellectual property law the author has the right to be mentioned when his/her work is accessed as described above and to be protected against infringement. For additional information about the Linköping University Electronic Press and its procedures for publication and for assurance of document integrity, please refer to its WWW home page: http://www.ep.liu.se/ © Karin Axelsson, Cynthia Novak Bachelor’s Thesis Support for Cell Broadcast as a Global Warning System Acknowledgements This work has been carried out within the Department of Science and Technology at the University of Linköping. We would like to thank our examiner and supervisor at this department, David Gundlegård, for introducing us to the subject and supporting us through the investigations and for his contribution during discussions. A special thanks to Ericsson AB in Katrineholm for giving us the possibility of testing Cell Broadcast in a mobile network. We also would like to thank Amir Baranzahi for his input and advice regarding measurement of battery consumption. Also Kjell Karlsson has been very helpful, supplying us with a workroom and measurement instruments. Thank you, Ann-Thérese Grüneberger. Your helpful comments and feedback made this a better thesis. Last but not least, thanks to all friends and family who were always willing to read and discuss this thesis with us. Karin Axelsson and Cynthia Novak Norrköping, June 2007 i Bachelor’s Thesis Support for Cell Broadcast as a Global Warning System Summary Cell Broadcast (CB) is a possible technical realisation of a global emergency alert system. It is a technique used for sending short text messages to all mobile stations (MSs) in a defined geographical area. To receive CB messages, the owner of an MS has to turn on the reception of CB messages on the MS and set one or more channels to receive information from. An potential effect of using CB is the increase in battery consumption of the mobile station due to the fact that an extra channel will be used to make the service available even when the network is otherwise congested. Another part of the service which leads to a potential problem is how to make CB messages available in different languages. Investigating these problems is the objective of this thesis and the studies it includes. During the first part of the thesis, we measured the battery consumption of MSs in different modes of operation in order to analyse how CB affects the amount of current drained. The tests showed that battery consumption increased only slightly when CB messages were being received at the MS. Results also show that other activities at the MS have a larger effect on the current drain than CB has. Although some of the results can be, and are, discussed, we believe that CB would have a small effect on the power consumption of an MS, particularly in a context where it would be used for emergency warning messages only. Important to mention is that is it always possible to turn off CB on an MS when the reception of emergency messages is not desired. This mentioned, it would however be wishful to confirm the conclusions further through the realisation of long-term testing. The second part of the thesis deals with the investigation of the MSs’ support for CB messages with different coding schemes. The investigation’s purpose was to examine how the use of different languages could be implemented in a warning system based on CB. Based on the investigation’s result, we have come to the conclusion that in the long term the usage of different coding schemes on the same channel is preferred. However, the usage of one, global, emergency channel is hard to realise since that requires a standardisation between all countries. In our opinion this may be achieved first in the long run and until then, the usage of separate channels seems to be necessary. Concerning the use of only one emergency channel we have come to two different conclusions, one short term and one long term solution, for how the coding schemes should be used for CB. The short term solution is to use the coding schemes for languages which can be stated in binary and in addition always sent out messages with “language unspecified”. A drawback of this solution is that UCS2 coding will not be enabled. In the long term we think that the best solution is to state the language with a letter abbreviation since this makes all languages of the world available and also has support