46 results about "Offset quadrature amplitude modulation" patented technology

Embodiments are provided for guard band utilization for synchronous and asynchronous communications in wireless networks. A user equipment (UE) or a network component transmits symbols on data bands assigned for primary communications. The data bands are separated by a guard band having smaller bandwidth than the data bands. The UE or network component further modulates symbols for secondary communications with a spectrally contained wave form, which has a smaller bandwidth than the guard band. The spectrally contained wave form is achieved with orthogonal frequency-division multiplexing (OFDM) modulation or with joint OFDM and Offset Quadrature Amplitude Modulation (OQAM) modulation. The modulated symbols for the secondary communications are transmitted within the guard band.

The present disclosure provides a multi-carrier optical transmitter, receiver, transceiver, and associated methods utilizing offset quadrature amplitude modulation thereby achieving significant increases in spectral efficiency, with negligible sensitivity penalties. In an exemplary embodiment, an optical transmitter includes circuitry configured to generate a plurality of optical subcarriers, a plurality of data signals for each of the plurality of subcarriers, and a plurality of modulator circuits for each of the plurality of subcarriers, wherein each of the plurality of modulator circuits includes circuitry configured to offset an in-phase component from a quadrature component of one of the plurality data signals by one-half baud period.

The invention relates to a method of reducing Peak-to-Average. Power Ratio in a transmitting device of a filter-hank multi-carrier system, which includes the steps of: performing constellation modulation (210) on data to be transmitted; performing K-point Discrete Fourier Transform (220) on a vector composed of K constellation symbols resulting from the constellation modulation: and performing Offset-Quadrature Amplitude Modulation (230) on a data vector resulting from the Discrete Fourier Transform, wherein the parameter K represents the number of subcarriers allocated for transmission of the data to be transmitted. With the solution proposed by the invention. PAPR of a signal can be significantly reduced without adding a large number of operations to thereby improve the efficiency of a power amplification circuit, to improve effective transmission, power and to alleviate nonlinear distortion of the signal during a power amplification.

The invention discloses an OFDM / OQAM (Orthogonal Frequency Division Multiplexing / Offset Quadrature Amplitude Modulation) system and a time frequency synchronization method thereof. The time frequency synchronization method comprises the following steps of: a coarse synchronization estimating step for estimating an estimated frequency offset value of a received baseband receiving signal frame sequence; a frequency offset compensating step for compensating the frequency offset of the received base band receiving signal frame sequence by using the estimated frequency offset value obtained by thecoarse synchronization estimating step; a fine synchronization estimating step for estimating an estimated time offset value of r2 (KTS) obtained by the frequency offset compensating step; and a timeoffset compensating step for compensating the time offset of the r2 (kTS) obtained by the frequency offset compensating step by using the estimated time offset value obtained by the fine synchronization estimating step so as to obtain r3 (kTS). In the invention, one-step synchronization is divided into two steps including coarse synchronization and fine synchronization; and the frequency offset of the baseband receiving signal frame sequence is first compensated by using the estimated frequency offset value obtained in the coarse synchronization and then the fine synchronization is carried out by using the compensated signal to obtain a final estimated time offset value so that the influence of CFO (Carrier Frequency Offset) during the fine synchronization is minimized and the time offsetestimation accuracy and the acquisition probability are improved.

The invention discloses a pilot design and synchronous channel estimation method for FBMC / OQAM (Filter Bank Multicarrier with Offset Quadrature Amplitude Modulation). Pilots are inserted at the transmitting end of the FBMC / OQAM system; at a system receiving end, the reversal symmetry of a data column adjacent to a pilot column is used to carry out moving correlation on received signals to determine a starting position; the corresponding relationship between the pilots on the same subcarrier is used in a frequency domain to obtain a frequency offset estimation value, and interference on estimation by the data column adjacent to the pilot column and channel noise is reduced through iteration; after frequency offset compensation, the data column adjacent to the pilot column is firstly assumed to be a zero protected column, pseudo pilots are thus calculated, channel estimation in the frequency domain is then carried out, and data symbols adjacent to the pilot column are then demodulated; and finally, the demodulated data symbols adjacent to the pilot column are used to calculate the pseudo pilots again to estimate the channel. The time offset, the frequency offset and the channel are estimated jointly in the FBMC / OQAM system, and the spectral efficiency is improved, and the estimation performance is also enhanced significantly.

Embodiments are provided for guard band utilization for synchronous and asynchronous communications in wireless networks. A user equipment (UE) or a network component transmits symbols on data bands assigned for primary communications. The data bands are separated by a guard band having smaller bandwidth than the data bands. The UE or network component further modulates symbols for secondary communications with a spectrally contained wave form, which has a smaller bandwidth than the guard band. The spectrally contained wave form is achieved with orthogonal frequency-division multiplexing (OFDM) modulation or with joint OFDM and Offset Quadrature Amplitude Modulation (OQAM) modulation. The modulated symbols for the secondary communications are transmitted within the guard band.

Embodiments of the invention disclose a method and a device for reducing a peak-to-average power ratio of an FBMC-OQAM (Filter Bank Multicarrier with Offset Quadrature Amplitude Modulation) signal, relating to the communication technical field. The method comprises the following steps of obtaining a to-be-sent symbol; generating a phase rotation factor vector; mapping the to-be-sent symbol to a real number symbol; obtaining a real number symbol after phase rotation; modulating the real number symbol after each phase rotation to obtain a modulated time domain signal; computing the PAPR (Peak-to-Average Power Ratio) for each modulated time domain signal; obtaining a phase rotation factor vector corresponding to the minimum PAPR and taking the phase rotation factor vector as an optimal phase rotation factor vector; obtaining a real number symbol after optimal phase rotation; and modulating the real number symbol after optimal phase rotation to time domain signal to send. By applying the embodiments, the real part data and the imaginary part data of the FBMC-OQAM signal are respectively corresponding to one optimal phase rotation factor vector, so that the PAPR of the FBMC-OQAM signal is further reduced.

The invention discloses a feedback-iteration-based OFDM / OQAM (orthogonal frequency division multiplexing / offset quadrature amplitude modulation) system and a time-frequency synchronization method thereof. The system and the method provided by the invention extend a one-step synchronization method of a frequency domain pilot frequency based time-frequency joint estimation method in the traditionalOFDM / OQAM system into a feedback iteration decision method. An initial time offset estimated value is firstly obtained by using time offset estimation; a pilot frequency bit error rate is compared with a preset decision threshold, if the pilot frequency bit error rate is no less than the preset decision threshold, a time offset trial value at the proximity of the initial time offset estimated value is selected to conduct iteration decision value by value until the bit error rate of the pilot frequency data part is less than the decision threshold value, the time offset trial value can be acted as a time offset estimated value for precise timing, and a frequency offset estimated value corresponding to the time offset trial value can be acted as a frequency offset estimated value for precise estimation; and the demodulated data are output in a bit mode, thus the acquisition probability of the time offset estimation in multipath channels can be effectively improved by the processing method.

The invention discloses a pilot sequence structure in an MIMO-OFDM / OQAM (Multi-input Multi-output-Orthogonal Frequency Division Multiplexing / Offset Quadrature Amplitude Modulation) system and a channel estimation method. Different pilot sequences are adopted by different antennae, the pilot sequence of each antenna is composed of three segments of symbol sequences, the length of each symbol sequence accords with the number of subcarriers, wherein the first segment of symbol sequence and the third segment of symbol sequence are all-zero symbol sequences, pilot signals are arranged at equal intervals in the second segment of symbol sequence, the pilot signal positions of all the antennas are different, the symbols of the pilot signals are randomly chosen from a candidate symbol set, and the interval between the pilot signals is two times the number of the antennas. The channel estimation method put forward by the invention can be utilized to eliminate inter-symbol interference and inter-subcarrier interference caused by multipath interference, so that the accuracy of the channel estimation of the MIMO-OFDM / OQAM system can be increased. Meanwhile, the pilot sequence structure decreases the peak-to-average power ratio of transmitted signals, and can meet the linear dynamic range of a radio frequency front-end high power amplifier and decrease the linearity requirement of the MIMO-OFDM / OQAM system on the high power amplifier.

A plurality of candidate transmission signals which are modulated according to a discrete Fourier transform (DFT)-spread filter-bank multi-carrier (FBMC) / offset quadrature amplitude modulation (OQAM) scheme and are capable of achieving a single carrier effect are generated. A candidate transmission signal having the smallest peak to average power ratio (PAPR) is selected and transmitted, so that a PAPR performance can be effectively improved.

The invention discloses an interference cancellation method. The method includes the following steps that: the mean and variance of received signals are calculated, so that the statistical information of the received signals can be obtained; the estimation logarithm probability-likelihood information of the received signals is calculated according to the statistical information of the received signals; the decoding logarithm probability-likelihood information of the received signals is calculated according to the received signals according to the estimation logarithm probability-likelihood information of the received signals, and the calculation of the statistical information of the received signals is updated; and the above operation is repeated until an agreed number of iterations is achieved, hard decision is performed on the decoding logarithm probability-likelihood information of the received signals, and data bit information obtained after the hard decision is outputted. The invention also discloses an interference cancellation device, an interference cancellation auxiliary method, a base station and a terminal. With the interference cancellation method, interference cancellation auxiliary method, the interference cancellation device, the base station and the terminal of the invention adopted, influence of system performance, caused by the residual inherent interference of an FBMC / OQAM (filter bank multi-carrier / offset quadrature amplitude modulation) system can be decreased, and the spectrum use efficiency and use flexibility of the OQAM / FBMC system can be improved.

The invention discloses a prototype filter fixed-point implementation method based on an OQAM-FBMC (Offset Quadrature Amplitude Modulation-Filter Bank Multicarrier) system. The method adopts a transmitting part and a receiving part; the transmitting part firstly partitions a complex signal into a real part signal and an imaginary part signal by an OQAM preprocessing module, then expands a frequency domain and carries out pulse shaping by an iFFT-PPN (Inverse Fast Fourier Transform-Poly Phase Network) synthesis filter bank module, and finally carries out parallel-serial conversion; and the receiving part corresponds to part of flow of the transmitting part, firstly, carries out parallel-serial conversion, then processes by an FFT-PPN analysis filter, and finally, completes regeneration of an original signal by an OQAM post-processing module. According to the prototype filter fixed-point implementation method disclosed by the invention, by carrying out simulation analysis on a wireless access system, introducing each functional module, carrying out fixed-point implementation on a filter bank and acquiring optimal fixed point numbers of a Phydyas fitler bank in different channel environments, the theoretical basis is provided for hardware implementation, hardware cost and signal transmission energy consumption can be greatly saved in the engineering application.

The embodiment of the invention discloses a multi-carrier signal detection method and device of an offset quadrature amplitude modulation filter bank. The multi-carrier signal detection method and device are applied to a data receiving terminal. The data receiving terminal intercepts a first signal in a baseband signal and filters the first signal to obtain a second signal; the second signal is averagely decomposed into a corresponding number of N point signals; fast Fourier transform is carried out on each N point signal to obtain the corresponding number of converted N point signals; each converted N point signal is descrambled according to a descrambling mode corresponding to a transmitting terminal scrambling mode, so as to obtain the corresponding number of descrambled N point signals; and the corresponding number of descrambled N point signals are superposed and then OQAM demodulation is carried out to obtain a real part or an imaginary part of the signal. According to the multi-carrier signal detection method and device of the offset quadrature amplitude modulation filter bank, each converted N point signal is descrambled according to the descrambling mode corresponding to the transmitting terminal scrambling mode, so that the receiving terminal can restore the real part or the imaginary part of the original signal.

The invention discloses a method for transmitting a pilot signal of a multi-carrier system, which belongs to the field of multi-carrier communication and comprises the following steps of: transmittinga pilot sequence of a frame header and a data symbol in a frame by adopting a filter bank multi-carrier OQAM / FBMC based on offset quadrature amplitude modulation; calculating an initial channel frequency response estimated value according to the noise correlation on different subcarriers in the pilot frequency sequence; carrying out orthogonal transformation on the initial channel frequency response estimation value, and setting a noise signal at a non-tap position of a channel to be zero; obtaining a tap position noise component according to the correlation of the noise in the transform domain and the noise signal of the non-tap position; and filtering the noise signal at the tap position, and converting the initial channel frequency response estimated value subjected to noise elimination back to the frequency domain to obtain a final channel estimated value. According to the method, the noise correlation in the transform domain is utilized to effectively estimate and eliminate the noise signal at the channel tap position, and the problem of poor channel estimation performance of the OQAM / FBMC system is solved.

The invention discloses a time domain channel estimation method and a time domain channel estimation device. The time domain channel estimation method comprises steps that a receiving end is used to receive an association relation between the receiving signal of the receiving end and a transmitting signal of a transmitting end in a time domain after demodulating a received orthogonal frequency-division multiplexing / offset quadrature amplitude modulation OFDM / OQAM signal; the receiving end is used to acquire statistic of receiving signal noises according to the association relation and a preset noise distribution characteristic; the receiving end is used to acquire the tap coefficient of the time domain channel according to the statistic of the receiving signal noises and the association relation; and the tap coefficient corresponding to the time domain channel is used to express the time domain channel of the transmitting signal from the transmitting end to the receiving end.

An apparatus and method for filter bank multi-carrier signal modulation with a low peak-to-average power ratio (PAPR) in a multiple antenna system are disclosed. According to embodiments of the present disclosure, in a multiple antenna transmission method, after a plurality of transmission candidate signals, which are modulated for each antenna using discrete Fourier transform (DFT) spread filter bank multi-carrier and offset quadrature amplitude modulation (FBMC / OQAM) techniques and are capable of obtaining a single carrier effect, are generated, a transmission candidate signal with a low PAPR can be selected and transmitted, and thus peak-to-average power ratio performance can be effectively improved, and interference between subcarriers can be eliminated by applying an Alamouti coding manner.

The invention relates to a Filter Bank Multi-Carrier (FBMC) transmitter implementation method, and belongs to the technical field of wireless communication. The method comprises the steps of: S1: carrying out Offset Quadrature Amplitude Modulation (OQAM) modulation on sent data streaming, then carrying out data block grouping on the modulated data streaming, and respectively carrying out IFFT; S2:designing a Peak to Average Power Ratio (PAPR) suppression module, implementing optimal phase searching, and after obtaining an optimal phase factor, respectively multiplying by each group of data blocks after IFFT; S3: designing a Poly-Phase filtering Network (PPN) module, and after inputting each group of optimized data blocks into a PPN, carrying out adding; and S4: adding two paths of I / Q delays and generating a FBMC signal. According to the invention, calculation complexity of an FBMC transmitter can be reduced, and an FBMC waveform with a low PAPR is obtained.

The invention discloses a parallel data processing method and device suitable for FBMC transmission. The parallel data processing method comprises the following steps: performing QAM modulation on theinput data in parallel; performing offset quadrature amplitude modulation (OQAM) on a modulated signal; then, filtering an OQAM symbol in the frequency domain by using the frequency domain extensionmethod, and transforming the filtered data into time domain data for processing; finally, processing the time domain data through the overlapping addition manner to achieve waveform hybrid and send out the waveform hybrid; carrying out waveform separation processing at a receiving end, and performing a series of demodulation steps correspondingly, and restoring the original transmitted data. The parallel data processing method proposed by the invention is combined with the FBMC-specific waveform hybrid transmission mechanism to avoid the efficiency loss caused by the frequency domain expansion, the transmission and reception process of the FBMC is effectively optimized, and the K (prototype filter overlap factor) times effective transmission rate can be reached under the same sampling ratecondition.

A method for signal modulation in a filter bank multi-carrier system is provided. A modulation method according to one embodiment of the present disclosure includes generating a plurality of different candidate transmission signals by modulating a complex symbol vector including a plurality of complex symbols in a discrete Fourier transform (DFT) spread filter bank multi-carrier (FBMC) / offset quadrature amplitude modulation (OQAM) scheme and selecting a candidate transmission signal having a lowest peak power or peak-to-average power ratio (PAPR) as a transmission signal, wherein the generating of the plurality of candidate transmission signals comprises applying a different phase offset to the complex symbol vector according to a candidate transmission signal to be generated.

A method for performing orthogonal frequency division multiplexing (OFDM) / offset quantization amplitude modulation (OQAM) includes obtaining a data burst. The method includes performing weighted circularly convolved filtering modulation on the data burst to produce an output signal. The method further includes a first wireless device transmitting the output signal to a second wireless device. The second wireless device receives an input signal from the first wireless device, and the second wireless devices performs weighted circularly convolved demodulation filtering on the input signal to produce the data burst.

The invention discloses a method for transmitting a pilot signal of a multi-carrier system, which belongs to the field of multi-carrier communication and comprises the following steps of: transmittinga pilot sequence of a frame header and a data symbol in a frame by adopting a filter bank multi-carrier OQAM / FBMC based on offset quadrature amplitude modulation; calculating an initial channel frequency response estimated value according to the noise correlation on different subcarriers in the pilot frequency sequence; carrying out orthogonal transformation on the initial channel frequency response estimation value, and setting a noise signal at a non-tap position of a channel to be zero; obtaining a tap position noise component according to the correlation of the noise in the transform domain and the noise signal of the non-tap position; and filtering the noise signal at the tap position, and converting the initial channel frequency response estimated value subjected to noise elimination back to the frequency domain to obtain a final channel estimated value. According to the method, the noise correlation in the transform domain is utilized to effectively estimate and eliminate the noise signal at the channel tap position, and the problem of poor channel estimation performance of the OQAM / FBMC system is solved.

A filter bank multi-carrier (FBMC)-offset quadrature amplitude modulation (OQAM) system is disclosed. The FBMC-OQAM system includes a processing circuitry which is configured to receive a signal over a transmission medium, equalize the signal by a convolution neural network (CNN) equalizer, wherein the CNN equalizer is configured to estimate the received signal without performing channel estimation, and output the estimated signal as a bit stream.

The invention discloses an orthogonal frequency division multiplexing (OFDM) / offset quadrature amplitude modulation (OQAM) system and a time frequency synchronization method thereof. In the system and the method provided by the invention, a one-step synchronization method of a frequency-domain-pilot-based time frequency joint estimation method in the conventional OFDM / OQAM system is extended into a multi-path parallel time frequency joint estimation method, and comprises the following steps of: first obtaining a primary estimated time offset value by using time offset estimation, and expanding the primary estimated time offset value into a regulated time offset test value sequence; then causing each regulated time offset test value to correspond to the demodulation recovery of a path of data respectively; and finally selecting a path of which the data of a pilot part has the smallest bit error rate as an accurate timing path. Therefore, the acquisition probability of the time offset estimation is greatly improved under the condition of correcting the inaccurate primary estimated time offset value to a great extent.

The invention discloses a filter bank multi-carrier method based on offset quadrature amplitude modulation, and belongs to the field of multi-carrier communication of a multi-input and multi-output filter bank. The technical problem that the imaginary part interference exists in a filter bank multi-carrier receiving end signal based on offset quadrature amplitude modulation is solved by using a space frequency block code scheme and a space time block code scheme of the filter bank multi-carrier method based on offset quadrature amplitude modulation. The filter bank multi-carrier method based on offset quadrature amplitude modulation comprises a data encoding step, a real and virtual interleaving modulation step, a data transmission step and a data receiving step. The effect caused by imaginary part interference of the filter bank multi-carrier receiving end signal based on offset quadrature amplitude modulation under a diversity scheme can be significantly reduced under the condition of ensuring the high-frequency spectrum utilization rate, and the error rate of the system is reduced.