Disclosed are a method and a device for transmitting/receiving a reference signal by a terminal in a wireless communication system. According to the present disclosure, the terminal receives control information from a base station and receives the reference signal based on the control information. The reference signal is transmitted on a specific antenna port and is positioned in the same symbol, on a time axis, and in the same subcarrier, on a frequency axis, as a different reference signal transmitted on at least one other antenna port. A method and a device may be provided, in which an Orthogonal Cover Code (OCC) is applied to the specific antenna port and at least one other antenna port and multiplexed through a Code Division Multiplexing (CDM) scheme and the OCC or a value acquired by shifting the OCC is applied to the subcarrier according to the index of the subcarrier.

The present disclosure provides a base station capable of improving the frequency utilization efficiency in uplink. In the base station (100), a receiver (112) receives a transmission signal to be repeatedly transmitted over a plurality of allocation units, and a reception signal processor (114) demodulates the transmission signal based on a combination of non-orthogonal multiple access where signals of a plurality of terminals are not orthogonal with each other, and orthogonal multiple access where signals of a plurality of terminals are orthogonal with each other.

An operation method of a base station in a communication system includes transmitting, to a terminal, a radio resource control (RRC) message including transmission configuration information (TCI)-state configuration information including information indicating a starting beam index and an ending beam index and reference signal related information; transmitting, to the terminal, a first downlink control information (DCI) including a first TCI indicating the starting beam index and first resource allocation information; and transmitting, to the terminal, a first physical downlink shared channel (PDSCH) through a resource indicated by the first resource allocation information by using a starting beam indicated by the first TCI.

Techniques for transmitting and receiving wireless communications over an unlicensed radio frequency spectrum band are disclosed, including techniques for transmitting and receiving system information blocks over the unlicensed radio frequency spectrum band, techniques for gaining access to the unlicensed radio frequency spectrum band by performing extended clear channel assessments (ECCAs), techniques for transmitting and receiving synchronization signals and reference signals over the unlicensed radio frequency spectrum band, techniques for identifying starting times of downlink transmissions over the unlicensed radio frequency spectrum band, techniques for transmitting and receiving clear channel assessment (CCA)-exempt transmissions over the unlicensed radio frequency spectrum band, techniques for performing random access over the unlicensed radio frequency spectrum band, and techniques for dynamically modifying a transmission mode over the unlicensed radio frequency spectrum band.

The present disclosure discloses a method and a system for providing a code cover to Orthogonal Frequency Division Multiplexing (OFDM) symbols in a multiple user system. A data sequence is received from each of a plurality of users. Further, a reference sequence is generated for the data sequence of each of the plurality of users. Each of the reference sequence is multiplied with a code cover which are orthogonal to each other. Each of the reference sequence is time-multiplexed with corresponding data sequence, to generate a corresponding multiplexed sequence. Further, a Discrete Fourier Transform (DFT) is performed on each of the multiplexed sequence to generate a corresponding DFT-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) symbol. Lastly, the corresponding DFT-s-OFDM symbol is processed for transmitting over corresponding one or more channels.

An aspect of the present invention provides a method for receiving a channel state information-reference signal (CSI-RS) by a terminal in a wireless communication system, the method comprising the steps of: receiving, from a base station, CSI-RS configuration information indicating a CSI-RS configuration about mapping of the CSI-RS; and receiving, from the base station, the CSI-RS which is transmitted through multiple antenna ports, on the basis of the received CSI-RS configuration information, wherein, when the CSI-RS configuration is a 32-port CSI-RS configuration into which four 8-port CSI-RS configurations are aggregated, a code division multiplexing (CDM)-8 pattern, in which the number of orthogonal weight vectors is 8, is applied to the 32-port CSI-RS configuration, wherein the CDM-8 pattern may be applied to one resource element (RE)-pair selected for each of the aggregated 8-port CSI-RS configurations.

An interference canceller comprises a composite interference vector (CIV) generator configured to produce a CIV by combining soft and/or hard estimates of interference, an interference-cancelling operator configured for generating a soft projection operator, and a soft-projection canceller configured for performing a soft projection of the received baseband signal to output an interference-cancelled signal. Weights used in the soft-projection operator are selected to maximize a post-processing SINR.

A code division multiaccess (CDMA) communications system with low probability of intercept, low probability of detect (LPI/LPD) includes at least one data dictionary stored on a storage device of a sender subsystem and a recipient subsystem. The at least one data dictionary includes at least one data predetermined start time and date, at least one data predetermined end time and date based on a mission length or a predetermined wrap time and date, a CDMA chip rate, and a complex zero-mean independent and identically distributed (iid) sequence where each complex number in the complex zero-mean iid sequence represents a CDMA chip stored on the storage device of the sender subsystem and the recipient subsystem. The system includes a tangible, non-transitory, machine-readable medium comprising machine-executable instructions which, when executed by at least one processor of a machine, cause the at least one processor to: receive a message, convert the message to symbols with corresponding phasors, determine a date and time to send the message, look up a data spreading vector for each corresponding phasor by providing a mutually agreed number of chips per phasor stored on the storage device of the sender subsystem and the recipient subsystem and by matching the date and time the message is to be sent to the at least one data predetermined start time and date and the at least one data predetermined end time and date. Each data spreading vector is multiplied by its corresponding phasor to create a data spread vector for each data spreading vector. The sender subsystem is configured to sequentially transmit each chip of each data spread vector as a signal.

Techniques for transmitting and receiving wireless communications over an unlicensed radio frequency spectrum band are disclosed, including techniques for transmitting and receiving system information blocks over the unlicensed radio frequency spectrum band, techniques for gaining access to the unlicensed radio frequency spectrum band by performing extended clear channel assessments (ECCAs), techniques for transmitting and receiving synchronization signals and reference signals over the unlicensed radio frequency spectrum band, techniques for identifying starting times of downlink transmissions over the unlicensed radio frequency spectrum band, techniques for transmitting and receiving clear channel assessment (CCA)-exempt transmissions over the unlicensed radio frequency spectrum band, techniques for performing random access over the unlicensed radio frequency spectrum band, and techniques for dynamically modifying a transmission mode over the unlicensed radio frequency spectrum band.

One embodiment relates to a method for transmitting a random access preamble in a transmitting sub-frame at a terminal device. The method (200) comprises: creating a random access preamble such that it comprises a plurality of random access sequences (S210); dividing the plurality of random access sequences into a number N, of groups, each of groups including two or more random access sequences (S220); performing code division multiplexing with respect to the groups of the plurality of random access sequences in a frequency domain, based on an orthogonal cover code selected for the terminal device from a pre-defined code set (S230); and transforming signals after the code division multiplexing into the time domain (S240). There are provided corresponding methods and devices.