A system that includes combiner circuitry configured to combine a first signal and a second signal to generate a third signal, wherein said third signal is output for transmission onto a communication medium. The system also includes nonlinearity modeling circuitry configured to model a nonlinear response of a nonlinear circuit, and generate a fourth signal through nonlinear distortion of a fifth signal using said model. The system also includes bin modification circuitry configured to generate said second signal through application of one or more weighting factors to frequency bins of said fourth signal, or of a transformed version of said fourth signal, and determine said weighting factors based on a difference, or squared difference, error metric.

Methods and apparatuses are provided with a solution to adjacent channel interference when a multi-carrier modulation system (e.g., OFDM) replaces a legacy modulation system and co-exists with it for a period of time. The adjacent channel interference can be reduced by blocking (setting to 0) and not using some of the carriers at the edge of the spectrum during the transition period. This effectively reduces the bandwidth of the channel and consequently, the adjacent channel interference caused by the multi-carrier signal. However, at some point in time, the legacy system will be turned off and the adjacent channel interference into the original channels will no longer be important. The present principles propose a mechanism to allow for the unblocking of the removed carriers once the interference problem becomes less strict.

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.

A transmission device including a time-domain windowing processing circuit to which a transmission symbol is input and in which the transmission symbol is multiplied by a time window. As the time window, a result of pre-convolving an arbitrary filter into an arbitrary time window is used.

Examples of digital architectures for OFDM backscatter communication are described herein that use RF switches and discrete loads to implement digitally controlled single-sideband OFDM backscatter devices. One or more transforms may be implemented, including one or more IFFTs, LUTs, and/or numerically-controlled oscillators using one or more sine LUTs.

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.

A data modulation and device and demodulation device for the multicarrier system are provided. The data modulation method includes: performing different 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.

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.

A transmission device including a time-domain windowing processing circuit to which a transmission symbol is input and in which the transmission symbol is multiplied by a time window. As the time window, a result of pre-convolving an arbitrary filter into an arbitrary time window is used.

Techniques for peak-to-average power ratio (PAPR) reduction are described. Wireless devices may provide signaling with respect to one or more PAPR shaping resources. For example, a wireless device may provide signaling of PAPR shaping capability information. PAPR shaping capability information may include information regarding one or more PAPR shaping resources the wireless device has a capability to implement. Additionally or alternatively, a wireless device may provide signaling of PAPR shaping information. PAPR shaping information may include information regarding shaping the signal by a wireless device prior to transmission in a communication link by implementing one or more PAPR shaping resources. Other aspects and features are also claimed and described.