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: 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: A method and an apparatus for obtaining synchronization of a terminal for communication between devices when a base station collapses are provided. The method includes, when a preamble signal is not received from the base station, maintaining a first synchronization for a predetermined time using a timer, transmitting a first preamble signal at a first synchronization point, performing a synchronization procedure with at least one neighbor terminal based on the first preamble signal, and, after the synchronization procedure, performing communication with the at least one neighbor terminal. In addition, when a preamble signal is not received from a base station, a first preamble signal from a relevant neighbor terminal is monitored for a predetermined time. When the first preamble signal is not received from the relevant neighbor terminal for the predetermined time, a second preamble signal is transmitted at an arbitrary point.

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 method for performing discovery at a terminal in a communication system is provided. The method includes generating a discovery request message including discovery target information, transmitting the discovery request message to a Proximity Service (ProSe) server that is located in a core network of the communication system and that manages communication of the terminal, and receiving a result of a discovery operation from another entity that performs the discovery operation of the terminal using discovery identification information about the terminal. The other entity is selected based on the discovery target information by the ProSe server.

Abstract: A method and an apparatus for direct communication between User Equipments (UEs) in a wireless communication system are provided. A method for communicating with a second UE by a first UE in the wireless communication system includes generating a discovery code used for communicating with the second UE, and transmitting the generated discovery code to one middle layer among a plurality of layers.

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 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.

Abstract: A distributed scheduling method in a Device-to-Device (D2D) communication system is provided. The method includes transmitting, to a peer device, first resource information including a link identifier and start position information of resources to be allocated, receiving, from the peer device, second resource information in which at least one of the resource start position information and a resource allocation amount is adjusted based on the first resource information, and determining the resource start position based on the first resource information and second resource information.

Abstract: A device and a method for performing Device to Device (D2D) communication in a wireless communication system are provided. The method includes transmitting information on a self-frequency band selected from all frequency bands for the D2D communication, to the second mobile station, receiving information on a counterpart-frequency band selected for the D2D communication, from the second mobile station, determining transmission and reception frequency bands to be used for the D2D communication, based on the information on the self-frequency band and the information on the counterpart-frequency band, transmitting data to the second mobile station in the determined transmission frequency band, and receiving data from the second mobile station in the determined reception frequency band.

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 method for operating a device in a wireless communication system supporting Device to Device (D2D) communication system includes receiving a reference signal from each of at least one transmitting device, estimating a frequency offset between the reference signals and a comparison reference signal corresponding to the reference signals, and adjusting a transmit frequency of a voltage controlled oscillator of the device using the estimated frequency offset estimation. An apparatus for compensating for a frequency offset of a device in a wireless communication system supporting Device to Device (D2D) communication system includes a frequency offset estimator configured to receive reference signals from each of at least one transmitting device, and estimating a frequency offset between the reference signals and a comparison reference signal corresponding to the reference signals, and a voltage controlled oscillator configured to adjust a transmit frequency using the estimated frequency offset.

Abstract: A link scheduling method in a system for performing Device-to-Device (D2D) communication includes periodically collecting information indicating whether to perform a medium access from at least one neighboring link determining at least one link expected to perform a medium access in a corresponding traffic slot among links with a higher priority than the terminal based on the collected information, and determining whether to perform the medium access of the terminal by considering only the at least one link expected to perform the medium access.

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: A switching method and apparatus in a broadband wireless communication system is provided. A method of an Advanced Base Station (ABS) for a Multicast Broadcast Service (MBS) in the broadband wireless communication system includes transmitting to an Advanced Mobile Station (AMS) a message including identification information for a primary carrier that provides the MBS among multiple carriers supported by the ABS, switching to the primary carrier with respect to the AMS, and transmitting MBS data through the primary carrier.

Abstract: In order to generate multiple-access signals, each transmitter transmits information by using all or a part of channel resources. The signal of each transmitter is mapped to an OFDM time-frequency resource space as a trellis modulation path. A mobile communication system maps trellis modulation paths of a plurality of transmitters to the same resource space. In order to effectively detect and distinguish signals of a plurality of transmitters transmitted through the same channel resource space, a receiver uses a message passing method between symbols and a path connection method. The receiver uses a state space expansion method, a backward pre-decoding method, and a successive interference cancellation method to more efficiently reconstruct a discovery signal.

Abstract: A method and an apparatus for synchronization for a device-to-device communication are disclosed. The method includes: instantly adjusting a synchronization phase value according to a time point when a synchronization signal is received, as soon as a device receives the synchronization signal from an adjacent device in an unconnected state; accumulatively storing at least one phase adjustment value according to a time point when at least one synchronization signal is received, whenever the device receives the at least one synchronization signal from at least one adjacent device in a connected state; and adjusting the synchronization phase value according to the stored at least one phase adjustment value when the device transitions from the connected state to the unconnected state.

Abstract: A method provides data communication while a Base Station (BS) is disrupted in a wireless communication system. The method includes, when a plurality of Mobile Stations (MSs) receive a preamble signal from a cluster header through a dedicated control channel while the BS is disrupted, sending a message requesting cluster member subscription to the cluster header, in the cluster header, including the plurality of MSs in a cluster member, configuring a cluster member list, and broadcasting the cluster member list, in a source MS among the plurality of MSs, sending a data transmission request message to the cluster header using the broadcasted cluster member list, in the cluster header, one of unicasting and broadcasting a response message for the data transmission request of the source MS, and, in the source MS, transmitting data to a target MS among the plurality of MSs based on the response message.

Abstract: A method and an apparatus for transmitting a packet in a system performing a Device to Device (D2D) direct communication are provided. In the method, whether to transmit a small packet is determined. When small packet transmission is determined, at least one peripheral reception device is informed of whether the small packet is transmitted at a scheduling point.

Abstract: A method and an apparatus for performing synchronization by a first device in a Device-to-Device (D2D) network are provided. The method includes detecting a synchronization signal from at least one second device during one period, determining a phase adjustment value depending on a number of synchronization signals, which have been detected from the at least one second device during the one period, adjusting a phase value of a first device using the phase adjustment value, and transmitting a synchronization signal if the phase value of the first device reaches a predetermined specific value.