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.

An Orthogonal Time Frequency Space Modulation (OTFS) modulation scheme that maps data symbols, along with optional pilot symbols, using a symplectic-like transformation such as a 2D Fourier transform and optional scrambling operation, into a complex wave aggregate and be backward compatible with legacy OFDM systems, is described. This wave aggregate may be processed for transmission by selecting portions of the aggregate according to various time and frequency intervals. The output from this process can be used to modulate transmitted waveforms according to various time intervals over a plurality of narrow-band subcarriers, often by using mutually orthogonal subcarrier tones or carrier frequencies. The entire wave aggregate may be transmitted over various time intervals. At the receiver, an inverse of this process can be used to both characterize the data channel and to correct the received signals for channel distortions, thus receiving a clear form of the original data symbols.

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).

A user equipment (UE) receives a plurality of synchronization signals, the plurality of synchronization signals including a plurality of first synchronization signals of different types and a plurality of second synchronization signals of different types. Reception of the plurality of synchronization signals comprises: reception of a first transmission by receiving a first group of the plurality of synchronization signals; and reception of one or more repeat transmissions of the first transmission, wherein each of the one or more repeat transmissions of the first transmission includes a repetition of the first transmission, wherein the first transmission and the one or more repeat transmissions of the first transmission are received within a first synchronization subframe. The UE demultiplexes the plurality of synchronization signals by performing time-division demultiplexing of at least one of the plurality of first synchronization signals and at least one of the plurality of second synchronization signals.

A method of a communication device configured with two or more multi-user coordination modes for communication with a plurality of users is disclosed. The method comprises determining an available spatial selectivity for the plurality of users, and selecting one of the two or more multi-user coordination modes based on the determined available spatial selectivity and a number of users of the plurality. Corresponding apparatus, communication receiver and computer program product are also disclosed.

Certain aspects of the present disclosure generally relate to wireless communications, and more specifically increasing user capacity through a frame structure which supports eMTC UL multi-user multiplexing. According to aspects, a UE may identify at least one narrowband region within a wider system bandwidth, determine at least one parameter assigned to the UE for transmitting symbols of a physical uplink channel in the narrowband region that are multiplexed with symbols transmitted by one or more other UEs, and transmit the physical uplink channel using the at least one determined parameter.

Embodiments of the present application provide a signal sending method, a device, and a system. A base station modulates, by using a first modulation scheme, signaling carried in a control channel, and modulates, by using a second modulation scheme, data carried in a traffic channel; and the base station sends, to UE, a signal obtained after modulation. In this way, the base station can independently select a modulation scheme for the control channel and the traffic channel, avoiding a case in which a modulation scheme used by the control channel and a modulation scheme used by the traffic channel must be the same, so that the base station can flexibly select a channel modulation scheme.

A transmission device includes: a modulator that selects an Orbital Angular Momentum (OAM) propagation mode among N (N is an integer equal to or greater than 2) OAM propagation modes in accordance with a value of bit data to be transmitted; and a transmitter that transmits a signal of the OAM propagation mode selected by the modulator.

A communications system comprises a maximum ratio combining (MRC) circuit for receiving a plurality of input data streams and for processing the plurality of input data streams using maximum ration combining to improve signal to noise ratio. A MIMO transmitter transmits the MRC processed carrier signal over a plurality of separate communications links from the MIMO transmitter, each of the plurality of separate communications links from one transmitting antenna of a plurality of transmitting antennas to each of a plurality of receiving antennas at a MIMO receiver.

The present invention focuses a system and or a complex synthetic method, which considering any not orthogonal, independent plurality signals with limited frequency bandwidth, not greater than any f0 central frequency, allows to develop a resultant complex signal with limited frequency bandwidth, not greater than any relative f0 central frequency instead of the one sum of all the relative plurality independent not orthogonal signals frequency bandwidths. The resultant complex signal is the linear combination of orthogonal complex signals plurality. Each one of such orthogonal complex signals is characterized by a limited frequency bandwidth, not greater than any relative f0, and each is in bijection with the relative independent not orthogonal signal considered in the beginning