This Technical Report (TR) represents the results of the Study on Public Warning System (PWS). The intent of this study is to identify requirements and aspects for a Public Warning System. The regulatory requirements and use cases for a public warning service have not been finalized in all regions (i.e. in the USA) therefore, the results of this study are not applicable for those regions which do not have regulatory requirements defined. The Public Warning System is intended to interwork with external networks to provide an end-to-end service. Therefore, service interactions with a Warning Notification Provider in external networks are considered within the scope of this document, although the specification of these interactions may be in other standards. If this occurs, a reference to that specification shall be made.