Abstract: A method for a base station to configure a channel state information (CSI)-reference signal (RS) is provided. The base station configures a CSI-RS antenna port for a terminal. The base station selects one of at least one port number mapping rule for mapping a port number on the CSI-RS antenna port for the terminal. The base station notifies the terminal of the selected port number mapping rule.

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: Disclosed herein are a terminal and an operation method thereof in a MIMO system. The terminal may use a reference signal for channel state measurement from a base station to calculate a first value that is a ratio of a signal transmitted from the base station to noise and a second value that is a ratio of interference from the base station and the noise. Further, the terminal may generate bit information by comparing a ratio of the second value and the first value with a predetermined threshold value and feedback the first value and the bit information to the base station.

Abstract: The transmitter maps an antenna port to a logical antenna port through a first virtualization. The transmitter maps the logical antenna port to a transceiver unit (TXRU) through a first operation. The transmitter maps the TXRU to a logical TXRU through a second operation. The transmitter maps the logical TXRU to a physical antenna element through a second virtualization.

Abstract: A method for a base station to configure a channel state information (CSI)-reference signal (RS) is provided. The base station configures a CSI-RS antenna port for a terminal. The base station selects one of at least one port number mapping rule for mapping a port number on the CSI-RS antenna port for the terminal. The base station notifies the terminal of the selected port number mapping rule.

Abstract: Disclosed herein is a terminal including: receiving a CSI-RS from a base station, generating CSI feedback information including indicators such as RI, PTI, and BI and a first PMI and a second PMI that are elements of a double codebook, on the basis of the CSI-RS and transmits the CSI feedback information to the base station through an uplink subframe corresponding to predetermined feedback periodicity.

Abstract: An apparatus for receiving a signal through an unlicensed band includes: a processor, a memory, and a radio frequency unit, wherein the processor executes a program stored in the memory to perform: receiving a secondary synchronization signal (SSS) in at least one remaining subframe except a subframe 0 or a subframe 5 of a plurality of subframes included in a discovery signal measurement timing configuration (DMTC), and detecting the SSS by using a subframe number of the subframe 0 or the subframe 5.

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: The transmitter maps an antenna port to a logical antenna port through a first virtualization. The transmitter maps the logical antenna port to a transceiver unit (TXRU) through a first operation. The transmitter maps the TXRU to a logical TXRU through a second operation. The transmitter maps the logical TXRU to a physical antenna element through a second virtualization.

Abstract: A method for receiving a reference signal including receiving a configuration about a subband from the base station through a higher layer signaling, wherein the RS is allocated to the subband; and receiving a subframe including a reference signal resource allocated by a unit of the subband, and an apparatus are provided.

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: A method and an apparatus for allocating uplink resources includes transmitting an uplink grant (UL Grant) for an unlicensed component carrier (UCC) to a plurality of terminals, wherein the UL Grant for a first terminal among the plurality of terminals includes a resource allocation information in which a transmission timing of the uplink data of a second terminal among the plurality of terminals is considered.

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 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 method in which a base station transmits a CSI (channel state information)-RS (reference signal) in a MIMO (multiple input multiple output) antenna system is provided. The base station periodically transmits a CSI-RS for first CSI to a terminal. The base station requests the terminal to transmit second CSI in a first subframe. When a CSI-RS occasion is configured, the base station transmits a CSI-RS for the second CSI to the terminal for a duration of the CSI-RS occasion from a second subframe or to the second subframe, which is a subframe after a first offset configured for CSI-RS transmission from the first subframe.

Abstract: Disclosed herein are a terminal and an operation method thereof in a MIMO system. The terminal may use a reference signal for channel state measurement from a base station to calculate a first value that is a ratio of a signal transmitted from the base station to noise and a second value that is a ratio of interference from the base station and the noise. Further, the terminal may generate bit information by comparing a ratio of the second value and the first value with a predetermined threshold value and feedback the first value and the bit information to the base station.

Abstract: Provided are a method for generating a CSI report and a terminal thereof. The method for generating a CSI report includes: receiving a CSI-RS from a serving cell of a base station through at least one CSI-RS resource included in a CSI-RS occasion; and generating the CSI report based on the CSI-RS received through the at least one CSI-RS resource.

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: A base station includes a plurality of first resource elements (REs) corresponding to at least two of a second orthogonal frequency division multiplexing (OFDM) symbol, a third OFDM symbol, and a fourth OFDM symbol of a first time slot, in a first CSI-RS resource pool configured in a first subframe including the first time slot and a second time slot subsequent to the first time slot. Furthermore, the base station transmits a CSI-RS at least one of REs included in the first CSI-RS resource pool.