Abstract: Systems and methods for peer-to-peer communication between user equipment using IP multimedia subsystem (IMS) functionality are provided. Each peer user equipment includes an IMS server and the peer-to-peer communication is established independent of network-based IMS servers. A third user equipment that does not include an IMS server can join the peer-to-peer communication using network-based IMS servers.

Abstract: The present invention relates to an infrared rays touch screen apparatus using an array of infrared elements in two opposite sides comprising: a plurality of infrared rays transmitting elements arranged sequentially in a first direction; a plurality of infrared rays receiving elements arranged sequentially in the first direction and in the opposite side of the plurality of infrared rays transmitting elements to receive infrared rays transmitted from the plurality of infrared rays transmitting elements; and a touch control unit which is operated in a first scan control mode which controls the plurality of infrared rays receiving elements and the plurality of infrared rays transmitting elements such that each infrared rays receiving element receives infrared rays from the infrared rays transmitting elements arranged in the opposite side and which is operated in a second scan control mode which controls such that each infrared rays receiving element receives infrared rays from the infrared rays transmitting elem

Abstract: A refined coordinate detection method for a touch panel, which more finely measures coordinates of an object without increasing the number of infrared emitting/receiving elements, and an error correction method, which minimizes position detection errors caused by received optical level errors due to external environment or their inherent characteristics, are provided. In the detection method, received levels of infrared emitting/receiving elements corresponding to left and right ends of object are measured and stored and the levels and a maximum received level are compared to calculate the refined coordinates. In the correction method, a lower limit level at a position where infrared reception is most significantly impeded by object is calculated through a comparison calculation of maximum and minimum received levels and it is detected that an object is present at a position only when a lower limit level at that position is not greater than the calculated one.

Abstract: A method for detecting the coordinates of multiple touching objects on an infrared touch screen, embodied on an apparatus, includes measuring and storing the maximum received level of a pair of infrared emitting and receiving elements, and initializing an index variable for identification of multiple touched spots, determining that the screen has been touched when a received level of a pair of infrared emitting and receiving elements, emission and reception of which is impeded by an object, is less than the maximum level, measuring the minimum level to detect center coordinates of the object, and reading an index variable for the center coordinates and determining that the center coordinates are new and setting an index variable for the center coordinates if no index variable is read for the center coordinates and storing the center coordinates and the index variable for the center coordinates.