Abstract: There are provided a method for processing an exceptional case of establishing a default bearer and a device therefor in order to solve a problem in that a user equipment cannot actually receive an IP service by accessing a packet network while failing in establishing the default bearer in a mobile communication system. A method for processing an exceptional case of establishing a default bearer in a mobility management entity includes: receiving a network attachment request from a user equipment; transmitting a network attachment acceptance including an activation request of the default bearer to the user equipment in response to the network attachment request; and cancelling a network attachment procedure when a completion response to the activation request of the default bearer is not received from the user equipment within a predetermined time.

Abstract: A method of offloading data is provided by a UE. The UE receives data from a macro cell base station over an MC-RB while an E-RAB between the macro cell base station and a gateway is established. The UE receives a first connection reconfiguration message from the macro cell base station after the E-RAB between a small cell base station and the gateway is established, and establishes an SC-RB according to the first connection reconfiguration message. Next, the UE receives a second connection reconfiguration message from the macro cell base station after a path between the macro cell base station and the gateway is switched to a path between the small cell base station and the gateway, and data for the MC-RB are exhausted on the macro cell base station. Then, the UE releases the MC-RB and switches to the SC-RB.

Abstract: Provided is a machine type communication system including a machine type communication device operating with a battery. The machine type communication system may monitor a residual power of the battery supplying power to the machine type communication device, and may output the monitored residual power to a device of a manager that manages the machine type communication device. Also, a point in time when the residual power of the battery is to be monitored may be determined based on the residual power.

Abstract: A discovery method is provided by a terminal in a terminal-to-terminal direct communication terminal-to-terminal direct communication. The terminal broadcasts a sequence, and receives an echo sequence on the sequence from other terminal. The terminal scrambles discovery information with the sequence, and transmits the scrambled discovery information.

Abstract: A method of offloading data is provided by a UE. The UE receives data from a macro cell base station over an MC-RB while an E-RAB between the macro cell base station and a gateway is established. The UE receives a first connection reconfiguration message from the macro cell base station after the E-RAB between a small cell base station and the gateway is established, and establishes an SC-RB according to the first connection reconfiguration message. Next, the UE receives a second connection reconfiguration message from the macro cell base station after a path between the macro cell base station and the gateway is switched to a path between the small cell base station and the gateway, and data for the MC-RB are exhausted on the macro cell base station. Then, the UE releases the MC-RB and switches to the SC-RB.

Abstract: A method and apparatus for perceiving access between a terminal and a small base station is provided. A macro base station transmits a small cell addition/change request message to a small base station that a terminal enters and transmits a message for access to the terminal when receiving a response message from the small base station. Then the macro base station obtains results of access between the terminal and the small base station and determines whether the access between the terminal and the small base station is completed based on the result of access.

Abstract: Provided is a machine type communication system including a machine type communication device operating with a battery. The machine type communication system may monitor a residual power of the battery supplying power to the machine type communication device, and may output the monitored residual power to a device of a manager that manages the machine type communication device. Also, a point in time when the residual power of the battery is to be monitored may be determined based on the residual power.

Abstract: Provided is a machine type communication system including a machine type communication device operating with a battery. The machine type communication system may monitor a residual power of the battery supplying power to the machine type communication device, and may output the monitored residual power to a device of a manager that manages the machine type communication device. Also, a point in time when the residual power of the battery is to be monitored may be determined based on the residual power.

Abstract: A method for discovery in device-to-device communications and an apparatus for the same are disclosed. The method performed in a device-to-device server supporting device-to-device discovery between a discovery terminal and a discoverable terminal may include receiving a device-to-device discovery participation message from the discoverable terminal, requesting a gateway to measure a proximity between the discovery terminal and the discoverable terminal, receiving a proximity measurement result from the gateway, and requesting the discovery terminal and the discoverable terminal to initiate a procedure of device-to-device discovery when the proximity measurement result satisfies a predetermined threshold. Thus, the procedure of device-to-device discovery may be performed efficiently.

Abstract: A method of providing service continuity between cellular communication and device-to-device communication is disclosed. A procedure for switching between cellular communication and device-to-device communication according to an example embodiment of the present invention may include transferring, by a gateway, a D2D bearer creation request message to an MME, transferring, by the MME, the D2D bearer creation request message to a base station, mapping, by the base station, D2D bearer QoS to D2D radio bearer QoS and transmitting an RRC connection reconfiguration message to terminals, receiving, by the base station, an RRC connection reconfiguration completion message indicating creation of a D2D radio bearer from the terminals, transmitting, by the base station, a D2D bearer creation response message indicating creation of a D2D bearer to the MME, and transferring, by the MME, the D2D bearer creation response message to the gateway.

Abstract: There are provided a device-to-device communication method, a mobile device using the same, and a device-to-device communication control method. The device-to-device communication method according to the invention may include receiving device-to-device communication resource allocation information and transmission characteristics information for device-to-device communication from a base station, and performing direct communication with an opposite terminal using the transmission characteristics information for device-to-device communication and the device-to-device communication resource allocation information, in which the transmission characteristics information includes the number of redundancy versions to be transmitted within at least one consecutive transmission time interval (TTI).

Abstract: Provided are a group control method for providing a machine type communication (MTC) service, and a mobile communication system using the method. The group control method includes categorizing one or more MTC devices into one or more MTC groups, assigning MTC group identifiers to respective MTC groups, setting MTC radio network temporary identifiers (MTC RNTIs) according to the MTC group Identifiers, and using the MTC_RNTIs for addressing the MTC devices belonging to the respective MTC groups.

Abstract: Provided is a link adaptation transmission and reception method in device-to-device (D2D) communication based on cellular mobile communication. An operation method of a terminal in the link adaptation method according to the present invention includes receiving information related to a first transmission through a D2D link, performing transmission for an opposite terminal using the information related to the first transmission, and determining information related to a second transmission after the transmission based on reception from the opposite terminal. Using the link adaptation method according to the present invention, an adaptive modulation and coding scheme may be provided at the time of data transmission on a D2D link while minimizing control of a base station, thereby reducing the complexity of a cellular network due to the D2D communication.

Abstract: Provided are a direct communication method of a terminal, a method of controlling device-to-device (D2D) communication, and a terminal device. The direct communication method of a terminal includes receiving downlink control information (DCI) from an evolved node base-station (eNB), extracting D2D transmission (Tx) or reception (Rx) grant information including a D2D pairing identity (ID) given to the terminal according to each D2D pair from the DCI, and performing data transmission or reception with a counterpart terminal according to Tx or Rx conditions set according to the D2D pairing ID.

Abstract: A resource allocation method of a base station for a device-to-device (D2D) communication link based on a cellular communication system includes providing operation information which includes information about one or more resource allocation patterns available for the D2D communication link to terminals which perform D2D communication according to each terminal and each D2D communication link, receiving a buffer status report (BSR) from the terminals which perform the D2D communication, and transmitting an indication value which indicates at least one of the resource allocation patterns based on the BSR. Accordingly, in the resource allocation method, low capacity of downlink control channels is required by the base station, yet flexible and efficient allocation of resources is enabled.

Abstract: Provided is a device-to-device (D2D) communication method based on a cellular communication system. The D2D communication method is based on a hierarchical D2D communication structure configured with a representative terminal and belonging terminals. Accordingly, the D2D communication method can be applied to various applications and business models. Also, a belonging terminal performs data communication only with an adjacent representative terminal due to a middle gathered structure through the representative terminal, so that the D2D communication method can be applied to an application requiring low power consumption. Further, the D2D communication method can be used as a solution for a Proxy machine-to-machine (M2M) device due to powerful security of mobile communication compared to that of a sensor network, reliability of data transmission, and speed of data transmission resulting from low latency.

Abstract: Provided is a method of controlling communication resources for cellular mobile communication system-based device-to-deice (D2D) communication. The method includes selecting, at a base station, at least two devices, which are performing cellular communication in the same cell, as D2D candidates, measuring environment-based information on the selected D2D candidates to select at least one D2D pair, and allocating uplink (UL) resources or downlink (DL) resources to the D2D pair.

Abstract: A method is provided for managing a tunnel when a mobile node moves from an existing visiting network to a visiting network which supports a mobile IP. A mobile node may detect a movement of the mobile node, configure a care-of address (CoA) and thereafter transmit a location registration (Binding Update) message to a home agent. The mobile node may create a second tunnel in the visiting network and set the second tunnel as a receiving-only tunnel while maintaining a first tunnel which is already used in the existing visiting network. The mobile node may receive a location registration completion (Binding Acknowledgement) message from the home agent, change the second tunnel to the tunnel capable of transmitting/receiving by modifying a routing table, and cancel the first tunnel.

Abstract: Provided are an overload control apparatus and method for a machine type communication (MTC) service. The overload control method includes, when an overload state has occurred, including an overload indicator (OI) in a MAC subheader in a random access response to be transmitted to a terminal and transmitting the random access response, before an MTC device wanting to perform a random access procedure transmits a random access preamble to the base station, searching for a random access response transmitted from the base station, when the transmitted random access response is searched for, peeking at the random access response and receiving it, and when it is determined that an OI is included in the random access response, waiting, at the MTC device, for a predetermined delay time and transmitting the random access preamble for performing the random access procedure to the base station.

Abstract: Provided is a contention based uplink transmission method. A base station may assign a contention based radio network temporary identifier (CB-RNTI) to a plurality of terminals, and terminals assigned with the same CB-RNTI may perform contention uplink transmission using the same radio resource.