The present disclosure provides a multi-carrier time-division multiplexing (MC-TDMA) modulation and demodulation method and system. Before multi-carrier modulation is performed on an input symbol, an interleaving allocation and an FFT may be performed, a time domain symbol may be transformed into a frequency domain symbol signal to perform a MDFT treatment. A sending end may adopt an analyzing filter bank structure, and pre-filtering and an IFFT may be performed on a signal successively. A pre-filter may be positioned between an NM point FFT and an M point IFFT, a PAPR value of the system may be reduced using the symmetry of a coefficient of a filter, and a frequency domain symbol signal may be allocated to different sub-bands for multi-carrier modulation.

In one aspect, a transmitter, for a first time interval, allocates first and second portions of a frequency band to first and second multicarrier modulation schemes with first and second subcarrier spacings that differ from one another. The data is transmitted to wireless devices in the first time interval using the first and second multicarrier modulation schemes in the first and second portions of the frequency band. For a second time interval, third and fourth non-overlapping portions of a frequency band are allocated to third and fourth multicarrier modulation schemes that have third and fourth subcarrier spacings that differ from one another. The third and fourth portions and/or schemes differ from the first and second portions and/or schemes. The data is transmitted in the second time interval using the third and fourth multicarrier modulation schemes in the third and fourth portions of the frequency band.

A device may obtain a sequence of input samples. The device may further obtain a first set of sequences, which may be based on discrete prolate spheroidal sequences associated with eigenvalues having a value larger than a first threshold. The device may determine a first projected sample sequence comprising a projection of the sequence of input samples to the first set of sequences and generate a signal based on the first projected sample sequence. Another device may determine a window of received samples of the signal and project the window of received samples to the first set of sequences or filter the window of received samples to obtain a first sample sequence. The detection of the received signal may then be performed based on the first sample sequence.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive an indication of a set of frequency domain resources allocated to the UE for communicating data over a wireless channel. The UE may receive an indication of a waveform type associated with the set of frequency domain resources. The waveform type may be based at least in part on a data type of the data, may be used for a defined amount of time, and may be one of a plurality of waveform types that are multiplexed together over different frequency domain resources within a total system bandwidth. The UE may communicate within the set of frequency domain resources according to the indicated waveform type and the data type.

An apparatus and digital signal processing means are disclosed for excision of co-channel interference from signals received in crowded or hostile environments using spatial/polarization diverse arrays, which reliably and rapidly identifies communication signals with transmitted features that are self-coherent over known framing intervals due to known attributes of the communication network, and exploits those features to develop diversity combining weights that substantively excise that co-channel interference from those communication signals, based on differing diversity signature, timing offset, and carrier offset between the network signals and the co-channel interferers. In one embodiment, the co-channel interference excision is performed in an appliqu? that can be implemented without coordination with a network transceiver.

A multicarrier system and data modulation and demodulation methods and devices for the multicarrier system are provided. The data modulation method includes: performing cyclic shifting on data sequences of L continuous symbols respectively, L?2; and modulating the cyclically shifted data sequences by use of a waveform function, an independent variable range of the waveform function being greater than or equal to a symbol interval of the L modulated symbols. The technical solution solves the technical problems in which the related art is not compatible with a LTE system or effectively suppressing out-of-band leakage or flexibly adjusting a symbol interval to adapt to different channel environments and exhibits poor demodulation performance, thus achieving effective suppression of the out-of-band leakage, having higher compatibility with the LTE system and improving demodulation performance and flexibility of adjusting a symbol interval by simple cyclic shifting.

Goal of the application is providing an alternative to the N-continuous algorithm in frequency domain for sidelobes reduction (OOB) suitable for SC-FDMA. A part of the time domain symbols is used as correction signal to ensure continuity of the signal and its derivatives at symbol boundaries, ie between previous symbol and guard interval (can be Zero Padding or Cyclic Pre-fix) of current symbol. Said time domain symbols are then FFT precoded, windowed, followed by IFFT and Guard Interval insertion. Also applied to FBMC.

A method for transmitting multiple communications of different types, in particular sporadic (MTC) or cellular (broadband) communication including symbols to be transmitted, corresponding to communication services implementing a modulation having M subcarriers of the FBMC-OQAM or OFDM-OQAM type. The method uses linear frequency filtering of a sequence of length N including symbols having L coefficients that are parametrizable according to the communication, L, N, and M being natural numbers, so as to generate N+L1 symbols, reducing out-of-band spurious emissions. The method also uses, no matter what the communication is, a single frequency/time transform (IFFT) having a size M, where N<M. For sporadic communications (MTC) in a lower frequency band, the constraints on the out-of-band side-lobes are more stringent on the filter and FBMC modulation is thus better adapted.

A receiver has an antenna to receive a pulse shaped transmit signal transmitted by a transmitter of a multi carrier (MC) pulse shaped transmission system. The pulse shaped transmit signal includes a predefined signal pattern. The predefined signal pattern is not subjected to pulse shaping. The receiver includes a filter to pulse shape filter the pulse shaped transmit signal to obtain data for the receiver. The predefined signal pattern is retrieved from the pulse shaped transmit signal prior to filtering the pulse shaped transmit signal.

The method is related to the smart frame design that contains multi-user single-carrier (SC) transmission to support 5G-and-beyond communication systems that permit enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable low-latency communication (URLLC) services. The method enhances the capacity of the system in line with the filter parameters to be selected according to the user's requirements and to meet the requirements of the desired and adjacent users.