Abstract: The present disclosure relates to a method and device for controlling a Downlink Data Notification (DDN) message, which can reduce the DDN messages that occur while a user equipment transits from an active (ECM-active) state to an inactive (ECM-idle) state. During a bearer activation procedure according to a request from a user equipment, the DDN message control apparatus of the present disclosure sets a DDN flag value to a predetermined value when uplink data is received. When a DDN message is received from outside, the apparatus identifies the DDN flag value and stores the DDN message in case that the DDN flag value is identical with the predetermined value.

Abstract: A clustering apparatus and method that can be used when synchronizing phase and frequency using a hybrid system of network assisted global navigation satellite system (AGNSS) and timing packet. A clustering apparatus for controlling timing is to determine a best master having a higher master-slave quality level among potential masters that can provide a timing packet based on a neighbor list provided by a server. The clustering apparatus organizes a cluster having linkability between the best master and at least one slave. The clustering apparatus performs synchronization between the best master and said at least one slave for each cluster.

Abstract: Embodiments of the present invention may provide an apparatus and a method for transmitting and receiving a random access channel (RACH) in a single carrier-frequency division multiple access (SC-FDMA) system. A frequency domain RACH signal may be mapped to a localized sub-frequency band of an entire frequency band available to the SC-FDMA system. A guard band including at least one sub carrier may be allocated between the RACH signal band and other channel signal bands. A guard time may be allocated between the RACE signal and other channel signals in the time domain. The RACH signal may include a short message including information related to a mobile station. The RACE signal may be detected in a frequency based method, a time based method or a sliding matched filter based method. Receiver complexity can be decreased if the RACH signal includes a CAZAC code sequence for a preamble. In such a case, a receive delay may be simply calculated and then adjusted more accurately.

Abstract: Embodiments of the present invention may provide an apparatus and a method for transmitting and receiving a random access channel (RACH) in a single carrier-frequency division multiple access (SC-FDMA) system. A frequency domain RACH signal may be mapped to a localized sub-frequency band of an entire frequency band available to the SC-FDMA system. A guard band including at least one sub carrier may be allocated between the RACH signal band and other channel signal bands. A guard time may be allocated between the RACE signal and other channel signals in the time domain. The RACH signal may include a short message including information related to a mobile station. The RACH signal may be detected in a frequency based method, a time based method or a sliding matched filter based method. Receiver complexity can be decreased if the RACH signal includes a CAZAC code sequence for a preamble. In such a case, a receive delay may be simply calculated and then adjusted more accurately.

Abstract: A method of reducing a paging load when a base station controller performs paging for a call service to a base station, and a mobile communication system thereof, are disclosed. The method includes: transmitting a paging message from the base station controller to a representative base station for each paging region when traffic occurs to an idle user equipment in an IP network; and relaying the paging message from the representative base station to the other base stations belonging to the same paging region as the representative base station.