A transmitter and a method therein for transmitting discovery signals to a receiver. The transmitter and the receiver are comprised in a radio communications system. The transmitter transmits two or more discovery signals over two or more directions. Each discovery signal is configured to span over a fraction of a carrier bandwidth.

The apparatus may be a base station. The apparatus processes a first group of synchronization signals. The apparatus processes a second group of synchronization signals. The apparatus performs a first transmission by transmitting the processed first group of the synchronization signals in a first synchronization subframe. The apparatus performs a second transmission by transmitting the processed second group of the synchronization signals in a second synchronization subframe.

The apparatus may be a base station. The apparatus processes a first group of synchronization signals. The apparatus processes a second group of synchronization signals. The apparatus performs a first transmission by transmitting the processed first group of the synchronization signals in a first synchronization subframe. The apparatus performs a second transmission by transmitting the processed second group of the synchronization signals in a second synchronization subframe.

A transmitter and a method therein for transmitting discovery signals to a receiver. The transmitter and the receiver are comprised in a radio communications system. The transmitter transmits two or more discovery signals over two or more directions. Each discovery signal is configured to span over a fraction of a carrier bandwidth.

The present invention is designed to improve spectral efficiency in a system that runs LTE/LTE-A by using a carrier in which LBT (Listen Before Talk) is configured. One aspect of the present invention provides a radio base station in a radio communication system where the radio base station and a user terminal communicate by using a carrier in which LBT is configured, and this radio base station has a measurement section that executes LBT in a predetermined carrier sensing duration and acquires an LBT result, and a transmission section that transmits a downlink signal based on the LBT result, and the predetermined carrier sensing duration includes a first carrier sensing duration and a second carrier sensing duration, which is shorter than the first carrier sensing duration.

A signal interface unit for a distributed antenna system includes a channelized radio carrier interface configured to communicate an uplink channelized radio carrier for a radio frequency carrier to a channelized radio carrier base station interface; an antenna side interface configured to receive an uplink digitized radio frequency signal from the distributed antenna system communicatively coupled to the antenna side interface, wherein the uplink digitized radio frequency signal includes baseband data having bits; and a signal conversion module communicatively coupled between the channelized radio carrier interface and the antenna side interface and configured to convert between the uplink digitized radio frequency signal and the uplink channelized radio carrier at least in part by performing an adjustment of the bits included in the baseband data for the uplink digitized radio frequency signal received from the distributed antenna system to comply with requirements of the channelized radio carrier base station interface.

The apparatus may be a base station. The apparatus processes a plurality of synchronization signals by performing time-division multiplexing (TDM) of at least one of a plurality of first synchronization signals of different types and at least one of the plurality of second synchronization signals of different types, the plurality of synchronization signals including the plurality of first synchronization signals and the plurality of second synchronization signals. The apparatus transmits the processed synchronization signals to a user equipment (UE).

The apparatus may be a base station. The apparatus processes a first group of synchronization signals. The apparatus processes a second group of synchronization signals. The apparatus performs a first transmission by transmitting the processed first group of the synchronization signals in a first synchronization subframe. The apparatus performs a second transmission by transmitting the processed second group of the synchronization signals in a second synchronization subframe.

The apparatus may be a base station. The apparatus sets a first numerology for at least one synchronization signal of one or more synchronization signals to be different from a second numerology for at least one data signal of one or more data signals. The apparatus transmits the one or more synchronization signals to a user equipment (UE) based on the first numerology. The apparatus transmits the one or more data signals to the UE based on the second numerology.

Embodiments of the present disclosure disclose a non-orthogonal multiple access transmission method, a base station, and UE. The method includes: configuring a new transmission mode for first UE, and notifying the first UE of the configured new transmission mode, where the new transmission mode indicates: a transmission signal of second UE located in a same cell as the first UE is superposed on a time-frequency resource allocated to the first UE, and the second UE is interfering UE of the first UE; and sending first downlink control signaling to the first UE, so that the first UE demodulates, according to the first downlink control signaling, received data sent by a base station, where the first downlink control signaling includes scheduling indication information of the first UE and scheduling indication information of the second UE.