Sender scorecards

Unsolicited communication is a major issue in digital communications and for the networks enabling such communication. With the increasing use of IP multimedia subsystem (IMS) networks, protection of time-critical communication, e.g., voice over IP (VoIP), from unsolicited messages becomes an important topic. The protection against unsolicited communication for IMS (PUCI) borrows the concepts from traditional e-mail spam filtering but needs to adapt to the nature of IMS communication being direct and time critical. In addition to the protection methods identified in TR 33.937 [1], we present a concept that uses a secure and interoperable scorecard that is associated with the caller and IMS communication. Depending on the outcome of the scorecard evaluation, the receiving domain can take appropriate actions such as denying or allowing a communication attempt. Scorecards are used to generate a standardized exchange format for the sender- and message-related information. B ased on Third Generation Partnership Project (3GPP) standards, we present an IMS architecture with scorecard elements, including basic operating procedures for the prevention of unsolicited communication for IMS (UCI).