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.

A method of transmitting data via a unipolar signal comprises allocating a symbol to one or more signals among a plurality of signals, applying pulse shaping to the plurality of signals to obtain a plurality of filtered signals, wherein the filtered signals are orthogonal signals, and transmitting the sum of the filtered signals as a unipolar signal, wherein the transmitted signal is a weighted sum of the filtered signals. The data can be recovered at the receiver by applying a plurality of orthogonal matched filters to the received unipolar signal to obtain a plurality of filtered signals, and performing symbol detection on the plurality of filtered signals to determine the received symbol. Apparatus for transmitting and receiving unipolar signals are also disclosed.

[Object] To realize IQ imbalance correction in a more preferable aspect. [Solution] An information processing device including: a calculation unit configured to calculate an error between predetermined reference coordinates on an IQ plane and a signal point of a received predetermined reference signal on a basis of a reception result of the reference signal on which phase modulation or quadrature amplitude modulation is implemented and mapping information of the reference signal; and a generation unit configured to generate correction data for correcting a deviation of a signal point of a received signal on a basis of a calculation result of the error.

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.

Embodiments herein disclose a method and system for designing a waveform for data communication. The method includes applying, by a phase rotation applying unit, a constellation specific phase rotation between consecutive data symbols in a data stream to obtain a constellation rotated data stream. Further, the method includes introducing, by a frequency domain pulse shaping filter, an inter symbol interference (ISI) between modulated data symbols of the constellation rotated data stream, such that the ISI develops the waveform of the constellated rotated data stream to be transmitted.

Embodiments herein disclose a method and system for designing a waveform for data communication. The method includes applying, by a phase rotation applying unit, a constellation specific phase rotation between consecutive data symbols in a data stream to obtain a constellation rotated data stream. Further, the method includes introducing, by a frequency domain pulse shaping filter, an inter symbol interference (ISI) between modulated data symbols of the constellation rotated data stream, such that the ISI develops the waveform of the constellated rotated data stream to be transmitted.

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 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.

Aspects of the present application provide methods and devices for time domain implementation of a single carrier waveform such as single carrier quadrature amplitude modulation (QAM) DFT-s-OFDM and single carrier Offset QAM (OQAM). A time domain implementation allows flexible symbol lengths, lower implementation complexity as a large IDFT operation is not required in the time domain and support for variable cyclic prefix (CP) length. An OQAM implementation utilizes a pre-processing step to convert a K complex QAM symbol sequence into a 2K OQAM symbol sequence and generates a sequence for transmission in the time domain as opposed to the frequency domain.

A transmitter module for a broadband data transmission system for radio communications, comprising at least one polyphase FFT filter bank is described. The at least one polyphase FFT filter bank is established as a synthesis polyphase FFT filter bank, wherein the at least one polyphase FFT filter bank comprises several filter units, wherein the transmitter module is configured to receive an input signal comprising a symbol sequence, and wherein the transmitter module is configured to transmit a signal based on the received input signal. Moreover, a receiver module for a broadband data transmission system and a data transmission system are described.