SIP presence location service

Abstract

This paper presents an innovative use of the Session Initiation Protocol (SIP) for the subscription and notification of geographic information in order to provide a privacy concerned location-based service. SIP is a signaling protocol used for establishing sessions in an IP network. It has been widely used for Internet conferencing and telephony. This research project aims to enhance the SIP presence model in order to protect sensitive geographic information. To achieve this goal, we thoroughly analyzed existing Location-Based Services (LBS), reviewed LBS designs’ pitfalls and identified several key privacy requirements. Based on this research, we presented a SIP flow that meets the privacy requirements. This SIP message flow includes SUBSCRIBE, NOTIFY and PUBLISH messages. A data format to carry geographic location information has also been introduced. The data format is based on Presence Information Data Format (PIDF). We define it as Location-enhanced PIDF, or LPIDF. LPIDF contains geographical information objects. We hope that the outcome of this research project will provide rich, convenient, privacy concerned architecture for LBS. Because LPIDF is based on SIP, this approach can be easily integrated into IP telephony services. LPIDF enables personalization of the Location-Based services address user privacy concerns and hereby increase their satisfaction.