Abstract: A method for synchronization by a D2D terminal in a D2D communication network through receiving a first D2D synchronization signal from at least one D2D synchronization source and performing synchronization according to a synchronization timing reference provided through the first D2D synchronization signal, and a method for negotiating whether to perform a role as a synchronization source with another D2D synchronization source through determining, when a D2D synchronization signal and a D2D synchronization channel are received from at least one D2D synchronization source, whether to maintain a role as the independent synchronization source based on negotiation information for negotiation between synchronization sources included in the D2D synchronization channel, and operating as a relaying synchronization source when the role as the independent synchronization source is not maintained, are provided.

Abstract: A first terminal receives a first Timing Advance (TA) value from a base station and includes a second TA value that is obtained based on the first TA value in a Scheduling Assignment (SA) signal. The first terminal transmits the SA signal to a second terminal at downlink (DL) timing for receiving a downlink signal of the base station in cellular communication. When a length of a Cyclic Prefix (CP) that is set for the D2D communication and a length of a CP that is set for the cellular communication are different, the first terminal transmits data of the D2D communication to the second terminal at first timing that is obtained by applying the second TA value to the DL timing.

Abstract: A synchronization group management apparatus of a node recognizes a node belonging to a different group if groups having mobility are moved and located in the same area, and performs an operation of merging the different groups into one group by changing the frame start time and the synchronization reference time of the node.

Abstract: Disclosed herein are a method of beamforming and a 3D antenna array. The method includes: transmitting a first control channel; receiving first feedback information on a first antenna set and a first precoding scheme of a plurality of antenna sets included in the 3D antenna array, which are determined based on the first control channel, from a first communication node different from the communication node; and beamforming a traffic channel to be transmitted to the first communication node using the first antenna set and the first precoding scheme.

Abstract: In a mobile wireless network system including a plurality of nodes communicating with each other, a node attempting to transmit data finds useable resources through performing carrier sensing on packet data unit (PDU) slots and transmits data through the found resources. A node attempting to receive data finds useable resource through performing carrier sensing on acknowledge (ACK) slots and receives data through the found resources.

Abstract: If a target node that enters into a transmission range is sensed, a mesh node of a wireless communication system selects an agent node having itself and a target node as a neighboring node among a plurality of neighboring nodes to form a link with the target node through the agent node. Also, the mesh node deletes the formed link if a target node that is out of a transmission range among a plurality of neighboring nodes is sensed, and forms a substitution path for at least a portion among an entire path of a connection including the deleted link.

Abstract: A beamforming apparatus and method for expanding coverage of a control channel are provided, by which neighboring communication devices are classified according to the number of beams that they can receive, and therefore the frequency or period of beam transmission is adjusted to transmit a control channel by a beamforming method. Hence, an overhead reduction and an increase in transmission rate can be achieved, and coverage holes can be prevented.

Abstract: A synchronization group management apparatus of a node recognizes a node belonging to a different group if groups having mobility are moved and located in the same area, and performs an operation of merging the different groups into one group by changing the frame start time and the synchronization reference time of the node.

Abstract: In a mobile wireless network system including a plurality of nodes, available resources of a transmitting node and available resources of a receiving node are searched for. Commonly overlapped allocatable resources among available resources of a transmitting node and available resources of a receiving node are searched for, areas corresponding to the calculated allocation resource number according to an allocation condition that is set in the allocatable resource area are selected, and the areas are allocated to the transmitting node or the receiving node.

Abstract: In a multicell communication system, a terminal that belongs to a second cell using the same subcarrier as a terminal that belongs to a first cell changes a pilot in an allocated basic resource block. Then, a base station that manages the first cell can estimate a channel of an interference signal transmitted from a second cell from a reception signal even though the reception signal includes an interference signal from the terminal that belongs to the second cell at the time of receiving a signal transmitted from the terminal that belongs to the first cell. Further, the base station that manages the first cell may reduce an interference signal from a reception signal by using a channel estimation value.

Abstract: In an orthogonal frequency division multiple access (OFDMA)-based wireless mesh network, a communication node receives information regarding a next transmission time of a 1-hop node and a 2-hop node through the 1-hop node, calculates next transmission intervals of the 1-hop node and the 2-hop node, determines a next transmission time of the communication node by using the next transmission intervals of the 1-hop node and the 2-hop node, and then transmits, to an 1-hop node of the communication node, the information of the next transmission time together with the information of the transmission time of the 1-hop node, received from the 1-hop node.

Abstract: A device for generating a transmission codebook in a communication system including a multi-input multi-output (MIMO) antenna according to an embodiment of the present invention includes: a frequency determiner that determines a frequency to allow the transmission codebook to have an optimal characteristic; a precoding matrix generator that generates a precoding matrix on the basis of the frequency; and a codebook generator that generates a retransmission codebook to be used for retransmission on the basis of the precoding matrix and generates the transmission codebook on the basis of the retransmission codebook.

Abstract: A method of managing a low-duty mode operation is provided by a small base station. The small base station determines a low-duty cycle pattern in which an available interval for data traffic transmission on active air interface and an unavailable interval for transmitting no data traffic are repeated, and provides a terminal with low-duty cycle pattern information. The low-duty cycle pattern information includes a length of the available interval and a start offset indicating a wireless frame at which the low-duty cycle pattern starts.

Abstract: When a transmitter communicating with a first receiver interferes with an adjacent second receiver, the transmitter receives a reference signal from the second receiver in order to transform a codebook to mitigate interference in the second receiver. A channel with the second receiver is estimated through the received reference signal, and a receiving correlation matrix is calculated based on the estimated channel. The inverse of the receiving correlation matrix is calculated from the calculated receiving correlation matrix, and the codebook is transformed using the calculated inverse of the receiving correlation matrix.

Abstract: A method for a first terminal communicating with a base station to perform direct communication with a second terminal is provided. The first terminal determines first timing for transmitting or receiving a first signal to or from the base station. Next, the first terminal determines second timing for transmitting a second signal for terminal discovery to the second terminal. When the first timing and the second timing overlap, the first terminal then changes either the first timing or the second timing.

Abstract: Provided is a frame structure designed for distributed access control and OFDMA transmission in a wireless mesh network. Also, a communication method and a network node based on the frame structure are provided. Mesh nodes included in the wireless mesh network may use the frame structure and thus, may have a high prospect of transmitting a network configuration information message and scheduling information for obtaining a resource. Also, a scheduling process of the mesh nodes may be completed within a short period based on the frame structure.

Abstract: A communication method of a terminal and a communication method of a base station for a direct communication link between terminals are disclosed. A base station schedules a reference terminal to transmit a ranging code, and schedules target terminals to receive the ranging code. The reference terminal measures the ranging code received from the target terminals, and transmits a ranging code measurement result to the base station. The base station selects a terminal from among the target terminals to form the direct communication link with the reference terminal among the target terminals based on the ranging code measurement result.

Abstract: A communication method for a third device that controls a first link established directly between a first device and a second device is provided. The third device allocates a first link identifier for identifying the first link. The third device transmits first information including the first link identifier to the first device and the second device. The third device receives, from the first device and the second device, second information including allocation acceptance information indicating the acceptance or rejection of allocation of the first link identifier.

Abstract: A method to generate a beamforming vector by a terminal includes receiving information on a first precoding matrix and a second precoding matrix from a serving base station; and generating a beamforming vector by linearly combining the first precoding matrix and the second precoding matrix.

Abstract: In a symbol mapping method, transmission data is encoded to output information bits and redundancy bits. The information bits and the redundancy bits are mapped to a symbol according to a first mapping scheme at a first transmission, and the information bits and the redundancy bits are mapped to a symbol according to a second mapping scheme at a second transmission.