Abstract: A method and apparatus for performing a state transition for Device to Device (D2D) communication are provided. The method includes determining whether D2D initiation is required, while a terminal is operating in a first or a second state defined by EPS (Enhanced Packet System) Mobility Management (EMM)-Deregistered and EPS Connection Management (ECM)-IDLE at a Non-Access Stratum (NAS) layer and Radio Resource Control (RRC)-IDLE. If the D2D initiation is required, the method includes transitioning to a third state defined by EMM-Registered and ECM/RRC-Connected and performing the D2D initiation through a mobile communication network. If a deactivation condition is satisfied or a D2D state update is completed in the third state, the method includes transitioning to a fourth state defined by EMM-Registered and ECM/RRC-IDLE, and if a state update or scheduling for D2D communication is required in the fourth state, the method includes transitioning to the third state.

Abstract: Disclosed is a 5G or pre-5G communication system for supporting a data transmission rate higher than that of a 4G communication system, such as LTE. Disclosed is a method for receiving data in a wireless communication system, comprising the steps of: receiving, by a terminal, transmission point change information from a first base station connected to a gateway; receiving, by the terminal, the data transmitted from the gateway to the first base station through a second base station serving the terminal; and re-receiving, by the terminal, data, of which the transmission has failed, through a third base station according to a change of a transmission point from the second base station to the third base station on the basis of the transmission point change information, when data transmission from the second base station to the terminal has failed.

Abstract: The present disclosure relates to a 5G or pre-5G communication system that is to support higher data transmission rates after 4G communication systems such as LTE. A method, by a MeNB, for switching a SeNB communicating with a UE in a wireless communication system, provided in an embodiment of the present disclosure, includes receiving, from the UE, a measurement report (MR) of the at least two SeNB neighboring with the UE, determining whether predetermined switch criteria are satisfied based on the MR, and transmitting, to the UE and a first SeNB or a second SeNB, a switch message indicating switching of an SeNB cooperating with the MeNB for communication with the UE from the first SeNB to the second SeNB, based on whether the switch criteria are satisfied.

Abstract: Disclosed is a 5G or pre-5G communication system for supporting a data transmission rate higher than that of a 4G communication system such as LTE. A method for communicating with user equipment (UE) by a base station is disclosed. The method comprises the steps of: identifying a type of one or more services required by the UE; notifying the UE of information on a configuration of a medium access control (MAC) layer and a physical (PHY) layer configured according to the identified type of one or more services; and communicating with the UE on the basis of the information on the configuration of the MAC layer and the PHY layer configured according to the identified type of one or more services.

Abstract: A method and apparatus for performing a state transition for Device to Device (D2D) communication are provided. The method includes determining whether D2D initiation is required, while a terminal is operating in a first or a second state defined by EPS (Enhanced Packet System) Mobility Management (EMM)-Deregistered and EPS Connection Management (ECM)-IDLE at a Non-Access Stratum (NAS) layer and Radio Resource Control (RRC)-IDLE. If the D2D initiation is required, the method includes transitioning to a third state defined by EMM-Registered and ECM/RRC-Connected and performing the D2D initiation through a mobile communication network. If a deactivation condition is satisfied or a D2D state update is completed in the third state, the method includes transitioning to a fourth state defined by EMM-Registered and ECM/RRC-IDLE, and if a state update or scheduling for D2D communication is required in the fourth state, the method includes transitioning to the third state.

Abstract: A method of providing an optimal transmission or reception (Tx/Rx) beam in a beamforming system. The method includes receiving a reference signal and selecting an optimal Tx/Rx beam that guarantees an optimal channel environment based on the received reference signal determining a possibility of occurrence of a Tx/Rx beam mismatch between the selected optimal Tx/Rx beam and a Tx/Rx beam used for transmitting information on the selected optimal Tx/Rx beam; and when there is the possibility of the occurrence of the Tx/Rx beam mismatch, performing at least one of widening a beam width of the Tx/Rx beam, increasing a number of Tx/Rx beams, reducing a period of a beam selection operation for selecting the optimal Tx/Rx beam, and reducing a transmission period of the reference signal. Other embodiments including a beamforming system are also disclosed.

Abstract: A method for allocating resources for Device-to-Device (D2D) communication in a transmitting terminal is provided. The method includes receiving broadcast resource allocation information for the D2D communication from a Base Station (BS), and measuring a channel quality of a downlink signal received from the BS and, if the measured channel quality is smaller than a predetermined threshold, conducting the D2D communication using the resource allocation information.

Abstract: An apparatus is configured to perform a method for performing distributed scheduling by a reception device configuring a target link corresponding to one of a plurality of links in a network in which the plurality of links for device to device communication exist. The method includes adding up resource allocation demand amounts included in resource information broadcasted by a counterpart device configuring the target link and one or more adjacent transmission devices by a preset Resource Unit (RU), and adjusting self resource information in consideration of resource position information included in the broadcasted resource information and the added resource allocation demand amount and transmitting the adjusted self resource information to the counterpart transmission device.

Abstract: An apparatus and a method for a handover in a communication system using beamforming are provided. The method includes the operations of receiving handover information from a serving base station, measuring, on the basis of beam scanning, a first reference signal transmitted from the serving base station and a second reference signal transmitted from a target base station, if the result of the measurement satisfies handover conditions, transmitting the result of the measurement to the serving base station, and receiving, on the basis of the handover information, a handover permission message from the target base station.

Abstract: A method and apparatus for performing a state transition for Device to Device (D2D) communication are provided. The method includes determining whether D2D initiation is required, while a terminal is operating in a first or a second state defined by EPS (Enhanced Packet System) Mobility Management (EMM)-Deregistered and EPS Connection Management (ECM)-IDLE at a Non-Access Stratum (NAS) layer and Radio Resource Control (RRC)-IDLE. If the D2D initiation is required, the method includes transitioning to a third state defined by EMM-Registered and ECM/RRC-Connected and performing the D2D initiation through a mobile communication network. If a deactivation condition is satisfied or a D2D state update is completed in the third state, the method includes transitioning to a fourth state defined by EMM-Registered and ECM/RRC-IDLE, and if a state update or scheduling for D2D communication is required in the fourth state, the method includes transitioning to the third state.

Abstract: A method of providing an optimal transmission or reception (Tx/Rx) beam in a beamforming system. The method includes receiving a reference signal and selecting an optimal Tx/Rx beam that guarantees an optimal channel environment based on the received reference signal determining a possibility of occurrence of a Tx/Rx beam mismatch between the selected optimal Tx/Rx beam and a Tx/Rx beam used for transmitting information on the selected optimal Tx/Rx beam; and when there is the possibility of the occurrence of the Tx/Rx beam mismatch, performing at least one of widening a beam width of the Tx/Rx beam, increasing a number of Tx/Rx beams, reducing a period of a beam selection operation for selecting the optimal Tx/Rx beam, and reducing a transmission period of the reference signal. Other embodiments including a beamforming system are also disclosed.

Abstract: A method and apparatus for performing initial entry for Device-to-Device (D2D) communication in a wireless communication system include transmitting an initial entry request including a service request for D2D communication to a Mobility Management Entity (MME) by a terminal, and if the service request for D2D communication is accepted, receiving information indicating that the initial entry request is accepted, including D2D communication information from the MME by the terminal.

Abstract: The present disclosure relates to a pre-5th-generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-generation (4G) communication system such as long term evolution (LTE). A communication method and apparatus using beamforming are provided. The method includes acquiring transmission beam specific, measurement information of a base station (BS) and measuring a reference signal (RS) transmitted through transmission beams of the BS according to the transmission beam specific, measurement information. The measurement information on each transmission beam is determined according to at least one of an elevation angle of the corresponding transmission beam, an azimuth of the corresponding transmission beam, a handover urgency, information on a handover failure, and information on a radio link failure (RLF). A mobile station (MS) may perform a measurement report or a handover process according to a result of the measurement.

Abstract: A method for supporting an application by Device to Device (D2D) communication in a wireless network includes acquiring range control information from an application upon selection of the application installed in the source device, controlling transmission power of a discovery signal for discovering a target device to conduct D2D communication, based on range control information defined for the selected application, and transmitting the discovery signal with the controlled transmission power. An apparatus includes a controller configured to acquire range control information from an application upon selection of the application installed in the source device, and control transmission power of a discovery signal for discovering a target device to conduct D2D communication, for the selected application based on range control information defined for the selected application, and a transmitter configured to transmit the discovery signal with the controlled transmission power.

Abstract: A discovery method for Device-to-Device (D2D) communication is provided. A terminal transmits a discovery service request message for D2D communication including one of application information and group information for a Proximity based Service (ProSe) to a server. The terminal receives, from the server, a discovery service key delivery message including a discovery service key corresponding to the one of the application information and the group information for a ProSe. The terminal acquires the discovery service key by decrypting the discovery service key delivery message, and performs discovery by encrypting a discovery code with the acquired discovery service key.

Abstract: A mobile terminal in a mobile communication system supporting device to device (D2D) communication, and a method for operating the mobile terminal are provided. The terminal includes a first radio frequency (RF) chain configured to transmit a mobile communication signal and a second RF chain configured to receive a mobile communication signal, for mobile communication with a base station, a switching unit including a plurality of switches configured to establish transmission and reception paths in the first and second RF chains, and a controller configured to control switching of the switching unit to establish transmission and reception paths of a D2D communication signal for D2D communication by combining a part of the first RF chain with a part of the second RF chain. The combination of the parts of the first and second RF chains is different according to a D2D communication frequency band.

Abstract: A method for controlling a path between terminals in a wireless communication system includes measuring a channel quality of a direct path with the another terminal when receiving a request for measuring the channel quality of the direct path from a higher entity, transmitting a first message comprising a result of the measuring the channel quality to the higher entity, and, when receiving a second message to instruct to switch to the direct path from the higher entity, setting the direct path with the another terminal. another embodiments including a terminal and a network entity are also disclosed.

Abstract: The present disclosure relates to 5th generation (5G) or pre-5G communication systems for supporting higher data transfer rates, following the 4th generation (4G) communication systems, such as long term evolution (LTE). A method for supporting handover with multi-connectivity in a wireless communication system is provided. The method includes sending a measurement report message including information of at least one small base station (eNB) to a macro cell eNB, receiving information of a new small eNB in a target cell from the macro cell eNB based on the measurement report message, and performing a random access procedure with the new small eNB in the target cell based on handover.

Abstract: The present invention relates to a two-step search procedure for D2D communication. A method for D2D communication includes: obtaining a discovery code and a multicast identifier to be used for transmitting additional information on an application program through a D2D multicast subframe, based on an identifier of an application program of a device; and broadcasting the discovery code and the multicast identifier in a discovery subframe.

Abstract: A method and an apparatus for synchronization for Device-to-Device (D2D) communication in unlicensed frequency bands are provided. The method includes determining whether a signal is detected during a preset time period within a synchronization period, after transmitting a synchronization signal during the synchronization period for the D2D communication, when it is determined that the D2D communication is to be performed, and starting the time period for the D2D communication and performing the D2D communication during the time period for the D2D communication, when it is determined that the signal is not detected.