Aspects of the present disclosure describe discovering physical cell identifiers in wireless communications. It can be determined to discover a physical cell identifier of one or more cells in a zone based at least in part on detecting a condition. A cell-specific signal can be received from at least one cell of the one or more cells in the zone. The cell-specific signal can be associated with one of a plurality of cell-specific signal hypotheses. The physical cell identifier of the at least one cell can be determined as one of a plurality of physical cell identifiers that corresponds to the one of the plurality of cell-specific signal hypotheses.

A radio communication system is provided with a high-power base station, a radio terminal which is located within a macro cell formed by the high-power base station, and a low-power base station which has a lower transmission output power than the high-power base station. The low-power base station sends, to the high-power base station, control information needed for the radio communication between the radio terminal and the low-power base station; the high-power base station sends, to the radio terminal, the control information received from the low-power base station; and the radio terminal performs radio communication with the low-power base station by using the control information received from the high-power base station.

A method of providing position assistance to a UE, the method comprising providing, by a location server, at least one unsolicited message, each message comprising one of data selected from a list comprising GNSS ephemeris assistance data, GNSS acquisition assistance data, OTDOA assistance data and eNB position data for a predefined area.

One disclosure of the present specification provides a method for performing measurement based on discovery signals. The method may comprise the steps of: receiving, from cells, discovery signals based on cell-specific reference signals (CRSs); and performing measurement based on the CRS-based discovery signals for a predetermined measurement period. If a measurement bandwidth is six resource blocks (RBs), the predetermined measurement period can be determined by 5*the measurement occasion periodicity of the discovery signals. If the measurement bandwidth is 25 resource blocks (RBs), the predetermined measurement period can be determined by 3*the measurement occasion periodicity of the discovery signals. Also, the discovery signals can be received for a discovery signal occasion duration defined by N consecutive subframes.

A method for identifying a mobile cell causing interference by a terminal connected to a first mobile cell, according to one embodiment of the present invention, comprises the steps of: acquiring system information of a fixed base station to which the first mobile cell is connected through a backhaul interface; acquiring a physical cell identifier of a second mobile cell neighboring the first mobile cell by a cell search; determining whether the second mobile cell causes interference to the first mobile cell on the basis of the physical cell identifier of the second mobile cell and the system information of the fixed base station; and reporting the physical cell identifier of the second mobile cell to the first mobile cell if the interference to the first mobile cell is determined to be caused by the second mobile cell.

Provided are a method and a device for selecting a channel of an unlicensed band in configuring carrier aggregation for a terminal using an unlicensed band cell which uses an unlicensed frequency band. The method may include: receiving, from a base station, channel candidate information of a secondary cell using an unlicensed frequency band; transmitting channel state information with respect to one or more channels generated using the channel candidate information; and adding, as the secondary cell, a channel selected on the basis of the channel state information by the base station; and a device.

A method for detecting a discovery reference signal includes: acquiring, by a user equipment, configuration information of a discovery reference signal, where the configuration information includes time-frequency resource information and sequence information of the discovery reference signal; receiving, by the user equipment, a first discovery reference signal sent by a base station; and determining a candidate time-frequency resource location of the discovery reference signal according to the time-frequency resource information, determining a candidate sequence of the discovery reference signal according to the sequence information, and, by detecting the candidate sequence of the discovery reference signal at the candidate time-frequency resource location, determining an actual time-frequency resource location of the first discovery reference signal and/or determining an actual sequence of the first discovery reference signal.

An OFDM transmitter spreads original data symbols with a complex-valued spreading matrix derived from a discrete Fourier transform. Spread data symbols are mapped to OFDM subcarriers. Spreading and mapping are configured to produce a transmitted spread-OFDM signal with a low peak-to-average power ratio (PAPR) and orthogonal code spaces. In MIMO systems, the complex-valued spreading matrix can comprise a MIMO precoding matrix, and the code spaces can comprise MIMO subspaces. In Cooperative-MIMO, a combination of low code-space cross correlation and low PAPR can be achieved.

A method and apparatus for performing coordinated communication between radio access points in a communication system are provided. The method includes receiving, by a first radio access point, a message requesting channel information from a second radio access point, transmitting, by the first radio access point, a response message in reply to the message requesting channel information to the second radio access point, transmitting, by the first radio access point, a message reporting the channel information to the second radio access point, and receiving, by the first radio access point, resource allocation information for Coordinated Multi-Point transmission and reception (CoMP) from the second radio access point.

A method of searching a cell in a mobile station of a communication system in which a plurality of cells are grouped into a plurality of cell groups, each cell group including at least two cells, includes: detecting a primary synchronization signal and a secondary synchronization signal from a received signal; and identifying a cell based on a combination of the primary synchronization signal and the secondary synchronization signal. The secondary synchronization signal is related to the cell group to which the mobile station belongs and the primary synchronization signal is related to the cell to which the mobile station belongs within the cell group.