Transparent session transfer in converged IP Messaging systems

It has recently become possible to connect heterogeneous networks as the 4th generation networks have evolved. Services converged and unified with similar services in each network are more widely provided than ever. OMA (Open Mobile Alliance), an international standardization organization concerning mobile technologies, is now standardizing various functions regarding CPM (Converged IP Messaging) for the messaging service of the 4th generation networks. These functions include a method for dealing with various devices used by a single user. When communicating with a conversation partner, a user with multiple devices may transfer the communication session from one device to another. In this session transfer, the records of previous communication need to be maintained and transmitted in order to ensure the consistency of user experience. In this paper, we introduce two (source device and target device-initiated) methods for session transfer in CPM, that ensure the consistency of user experience; via the guaranteed delivery of session history stored before the transfer and the messages temporarily stored during the transfer, these methods permit transparent transfer causing minimal interruption in the conversation. With our prototype for session transfer in CPM, we demonstrate that the methods are effective in session transfer without loss of any data or unnecessary delay in conversation.