System and methods for shaped single carrier orthogonal frequency division multiplexing with low peak to average power ratio are provided. The system receives an input signal and modulates the input signal to form Dirichlet kernels in a time domain to generate an offset Dirichlet kernel output time array where each Dirichlet kernel has a main lobe and a plurality of side lobes. Modulating the input signal suppresses a peak to average power ratio of the offset Dirichlet kernel output time array by reducing the plurality of side lobes of each Dirichlet kernel and respective amplitudes of the side lobes.

Embodiments of the present invention provide a data transmission method and apparatus, and the method includes: modulating to-be-sent information bits according to a lower order constellation diagram, and generating 4m lower order modulation symbols; multiplying a precoding matrix Q by a column vector including every four lower order modulation symbols in the 4m lower order modulation symbols, to obtain 4m to-be-sent higher order modulation symbols corresponding to a higher order constellation diagram; and respectively and correspondingly sending the 4m to-be-sent higher order modulation symbols on different carriers of two antennas. The to-be-sent higher order modulation symbols include some or all to-be-sent information bits. Therefore, the same signal can be simultaneously sent on different carriers of multiple antennas, and frequency diversity and space diversity are implemented, so that transceiving performance of data transmission is improved.

An apparatus including: a communication unit configured to perform radio communication; and a control unit configured to perform control such that control information regarding a resource to which a filter for limiting a width of a guard band in a frequency band to be used in the radio communication is applied is transmitted to an external apparatus through the radio communication. The filter improves frequency use efficiency.

An apparatus including: a communication unit configured to perform radio communication; and a control unit configured to perform control such that control information regarding a filter length of a filter for limiting a width of a guard band in a frequency band to be used in the radio communication is transmitted to an external apparatus through the radio communication. The filter length is determined in accordance with at least one of a frequency resource and a time resource for the radio communication. The apparatus enables a filter improving frequency use efficiency.

A transmitter of a DFT-based communications system including an orthogonal precoder for transforming modulated data symbols using a unitary transform, wherein the data 5 symbols are mapped to subcarriers of the transmitter and the computational complexity of the transform is linear with respect to the number of the subcarriers.

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.

Different numerologies may be used to communicate orthogonal frequency division multiplexing (OFDM)-based signals over different frequency sub-bands of a given carrier. This may allow the OFDM-based signals to efficiently support diverse traffic types. In some embodiments, the numerology of OFDM-based signal depends on a bandwidth of the frequency sub-band over which the OFDM-based signals are transmitted. In some embodiments, the OFDM-based signals are filtered OFDM (f-OFDM) signals, and the pulse shaping digital filter used to generate the f-OFDM signals allows the receiver to mitigate interference between adjacent f-OFDM signals upon reception, thereby allowing f-OFDM signals to be communicated over consecutive carriers without relying on a guard band.

This disclosure provides methods, devices and systems for reducing PAPR in wireless communications. Some implementations more specifically relate to suppressing the amplitudes of a data signal that exceed a threshold amplitude level. In some implementations, a transmitting device may detect one or more peaks associated with a data signal to be transmitted to a receiving device. A peak may be any sample of a data signal having an amplitude that exceeds a threshold amplitude level. The transmitting device generates peak suppression information indicating the amplitude, a phase and a position of each of the samples associated with the detected peaks. The transmitting device adjusts the data signal by reducing the amplitudes associated with the detected peaks and transmits the adjusted data signal, with the peak suppression information, to the receiving device. In some implementations, the transmitting device may compress the peak suppression information to reduce the overhead of the transmission.

Methods, systems, and devices for wireless communications are described. A transmitting device may identify a first signal in a time domain, the first signal including multiple sequences spanning a bandwidth for multiple symbol periods. The transmitting device may segment the first signal into signal segments, where each signal segment corresponds to a respective symbol period of the multiple symbol periods. The transmitting device may apply a first transform operation to each signal segment of the signal segments and apply a bandwidth restriction in the frequency domain to the transformed signal segments. Then, the transmitting device may apply a second transform operation to each transformed signal segment to return the bandwidth-restricted segments to the time domain. The transmitting device may generate a second signal in the time domain based on the bandwidth-restricted segments. The transmitting device may then transmit the second signal to a receiving device.

Systems and methods of performing data transmission and reception in a communication system are presented. In one exemplary embodiment, a method performed by a wireless device for transmitting a signal in a first communication system that is frequency-domain multiplexed with a second communication system may include generating (201), by a modulator (401), a modulated signal that represents one or more information symbols. The modulated signal may include one or more modulation symbols of the first communication system. The method may also include filtering (203), by a pulse shaping filter (403), the modulated signal to obtain the filtered modulated signal. The pulse shaping filter (403) may be configured to operate with a period that corresponds to the symbol rate of the second communication system. In addition, the method may include transmitting (209), by a transmitter (409), the filtered modulated signal at a carrier or sub-carrier frequency of the first communication system.