249results about How to "Lower peak-to-average ratio" patented technology

There is disclosed a power supply stage (202), comprising: generating means for generating a power supply voltage from a high efficiency variable voltage supply (204) in dependence on a reference signal; adjusting means for receiving the generated power supply voltage (220), and adapted to provide an adjusted selected power supply voltage tracking the reference signal (216) in dependence thereon.

A proactive networking system and method is disclosed. The network anticipates the user demands in advance and utilizes this predictive ability to reduce the peak to average ratio of the wireless traffic and yield significant savings in the required resources to guarantee certain Quality of Service (QoS) metrics. The system and method focuses on the existing cellular architecture and involves the design and analysis of learning algorithms, predictive resource allocation strategies, and incentive techniques to maximize the efficiency of proactive cellular networks. The system and method further involve proactive peer-to-peer (P2P) overlaying, which leverages the spatial and social structure of the network. Machine learning techniques are applied to find the optimal tradeoff between predictions that result in content being retrieved that the user ultimately never requests, and requests that are not anticipated in a timely manner.

The invention provides a method for sending synchronization signals. The method includes the steps that the synchronization signals of each sub-band are generated corresponding to each sub-band according to the ID of a cell and the serial number of a corresponding absolute sub-band of each sub-band, wherein the synchronization signals generated by the different sub-bands are mutually different; all points of the synchronization signals of each sub-band are mapped to the time-frequency resource positions of the synchronization signals of each sub-band where the pointes are located for transmitting, wherein time-frequency resources of the synchronization signals comprise all downlink resources on the whole sub-bands in a synchronization frame. By the application of the method for sending the synchronization signals, the peak-to-average ratio of time-domain signals can be reduced.

The invention discloses a broadband power line carrier communication physical layer emission signal processing method based on OFDM. The method includes: receiving data from a link layer, and dividing the data into frame control data and load data; performing channel coding on the frame control data and the load data, and modulating the frame control data and the load data after channel coding to subcarriers; performing inverse Fourier transform on the modulated frame control data and the load data, performing power control, and generating a time domain frame control symbol and a time domain load symbol; and adding a cyclic prefix to the time domain frame control symbol and the time domain load symbol, adding a time domain leading symbol, performing windowing processing, and generating physical layer emission signals. According to the method, the utilization rate of the frequency band is high, the transmission rate is high, and the intersymbol interference resistance and the channel fading resistance are excellent.

The invention relates to a multi-carrier transmission method and a multi-carrier transmission device based on selected carrier modulation. The multi-carrier transmission method comprises the steps that a transmitting end groups sub-carriers in an orthogonal frequency division multiplexing (OFDM) system and correspondingly groups bit data to be transmitted, after grouping, one part of bit data in each group of data selects n-k sub-carriers from n sub-carriers of each group as virtual carriers, the other part of bit data is modulated into k symbols which are mapped to the remaining k sub-carriers, and virtual carriers and the carriers which carry the data form OFDM symbols and then are transmitted; and a receiving end groups balanced receiving frequency domain symbols in a way as the same as the grouping way of the transmitting end, virtual carrier position identification is conducted in each group of symbols, virtual carrier positions are mapped to be bits to obtain the first part of data , virtual carrier position symbols in each group are removed and the remaining k symbols are demodulated to obtain the second part of data. The multi-carrier transmission method and the multi-carrier transmission device based on the selected carrier modulation solve the problem that the energy consumption of the traditional OFDM system is high in order to obtain more information under the situation that the bandwidth and the noise power of the system are determined.

The invention discloses a signal crest trimming method, which comprises the following steps of: computing the amplitude and phase of an input signal x(t), and if the amplitude, which is represented as the absolute value of x(t), of the input signal x(t) exceeds a threshold, subtracting the threshold from the signal to obtain a noise signal; performing molding filtration on the noise signal to obtain a same-frequency spectrum noise signal; and subtracting the same-frequency spectrum noise signal from the input signal x(t) of which the amplitude exceeds the threshold, and outputting the crest-trimmed signal. The technical scheme of the invention has the advantages of simplicity, high efficiency, relatively lower hardware equipment resource consumption in particular realization, short processing time delay, and the capacity of effectively performing crest trimming on randomly appearing signal peaks exceeding the threshold so as to reduce the peak-to-average power ratio of the signal.

The invention discloses a new emission method and reception method of multi-user block transmission communication. The emission method is that the Nu userí»s data are divided as the unit with K symbols; the K symbols of each user are repeated N times at time domain; and each of them is formed to Nu pectination frequency spectrum symbol sequences whose length are M; the sequence are modulated as quadrature carrier to make the each userí»s symbol sequence frequency spectrum not be aliasing each other; the Nu symbol sequences are superposed to form data blocks whose length is M; thus, the steps of partitioning and multiple access are completed. Correspondingly, the reception method is that multiple access separation is did according to the frequency spectrum took up by the user who need to receive to gain K symbol sequences of the user needed. The technical proposal of the invention is adopts to utilize the quadrature carrier modulation to do multiple access at the emission end, and utilize the jump corresponding operation with low complexity to separate the user data at the reception end. Thus, the complexity of the post-treatment is reduced.

The invention relates to the technical field of signal transmission, and discloses a frequency division multiple access method of a variable-bandwidth FMT (frequency modulated transmitter) based on single-carrier transmission. The frequency division multiple access method comprises the following steps: S1. different users transmit variable-bandwidth subcarrier signals synchronously at the transmitting end, wherein the subcarrier signals are obtained through filtering of original data to be transmitted by the users; and S2. the signals sent from different users are received in parallel at the receiving end. In the frequency division multiple access method disclosed by the invention, (1) the bandwidth of subcarriers transmitted by each user is variable (subcarriers of different bandwidth have different resistance to time selective fading and frequency selective fading), and the bandwidth of the subcarriers needs to meet a certain condition; (2) the variable-bandwidth subcarriers are filtered single-carrier signals; and (3) a transmitter transmits data synchronously, and the data is demodulated in parallel by a receiver, thus the realizing complexity of the transmitter and the receiver is reduced, the requirement of the system on synchronization and the peak-to-average power ratio of the system are reduced, and the resource allocation efficiency is improved simultaneously.

The invention discloses an LTE system orthogonal frequency-division multiplexing (OFDM) signal peak-to-average ratio suppression method combining constellation expansion with tone reservation. According to the suppression method, an active constellation expansion intelligent gradient mapping algorithm principle and a tone reservation least square estimation algorithm are combined, and control over the signal peak-to-average ratio performance, the bit error rate performance of a system and the out-of-band frequency spectrum extension performance of transmitting signals is effectively achieved by correcting the position of constellation points. A high convergence speed can be obtained, and the system operation time is effectively optimized, so that it is ensured that under the condition of little influence on the bit error rate performance of the system, the OFDM signal peak-to-average ratio is reduced substantially, and the overall comprehensive performance of the LTE system is improved.

The method comprises: after sending end makes inverse fast Fourier transform (IFFT), it determines the amplitude value of OFDM signals. The invention provides a companding function for making transform in order to make the transformed amplitude value submits to the linear function distribution and the phase of signal keep unchanged; the receiving end makes inverse companding transform for amplitude value of the received signals, and then makes fast Fourier transform (FFT) and decode for it.

This invention relates to an OFDM transmission method of a low peak and equal ratio, which carries out reassembling of real part and a virtual part to the vector signal sequences got from the code regulation and serial-parallel transformation to get real vectors then carries out an extended dispersed Fourier transformation to the real vectors and a conjugate symmetric extension and a mean square root rising cosine shaping to be imaged onto a set of sub-carries of the OFDM to generate OFDM signals with fine spectrum performance and low peak and equal ratio.

The invention discloses a low peak-to-average ratio wireless light transmission method with clipping moving. The feature that one of paring signals in ACO-OFDM time domain signals must be zero is utilized, if a positive signal in the pairing signals exceeds the set threshold value, clipping is conducted on the positive signal, and the clipped quantity is put at the zero position in the paring signals, and therefore the function of reducing the PAPR is achieved. The low peak-to-average ratio wireless light transmission method is easy to achieve, the PARP of an ACO-OFDM wireless optical communication system can be effectively reduced, system power consumption is reduced, the requirement for the linearity of a power amplifier and an LED lamp is lowered, nonlinear distortion of the signals in electricity and light domains is reduced, and therefore the receiving performance of the system is improved.

The invention relates to a dynamic compensation method for reducing LED (Light Emitting Diode) nonlinear distortion of a visible light Flip-OFDM (Orthogonal Frequency Division Multiplexing) communication system. The method comprises the following steps: segmenting a modulated subcarrier data vector into a plurality of non-overlapped subsequences; multiplying by a corresponding weighting coefficient, extending to be a hermitian symmetric sequence and then performing IFFT (Inverse Fast Fourier Transform); selecting a weighting coefficient for keeping the negative signal amplitude of a combined signal to be minimum; decomposing the polarity of the combined signal into a Flip-OFDM positive signal and a flip negative signal and limiting the amplitude; carrying an end cut signal of the positive signal at a zero signal position corresponding to the flip negative signal as a compensation signal; restoring the positive signal by a receiving end through the compensation signal. By using the method, PAPR (Peak to Average Power Ratio) in the Flip-OFDM system can be effectively suppressed, and the LED nonlinear distortion is reduced, so that the usability and the reliability of the system are greatly improved.

The present invention discloses a method for reducing the signal peak-to-average ratio in an FBMC system. According to the method, firstly, a signal is pre-processed at a signal transmission end and the data overlapping condition is avoided even after data are multiplied by a phase rotation factor after being subjected to constellation mapping. Secondly, in combination with the conventional PTS method, data are partitioned, and a set of data smallest in peak-to-average ratio among multiple sets of data is selected and transmitted. Therefore, the signal peak-to-average ratio is well reduced. Meanwhile, the signal demodulation is conducted at a receiving end according to the discriminant rule of signals. In this way, the transmission of the sideband information is avoided. According to the technical scheme of the invention, the peak-to-average power ratio of the FBMC system is reduced, while the information demodulation of the receiving end is enabled without the transmission of the phase rotation factor. Under the same condition, the utilization rate of spectrum resources is improved and the use efficiency of the entire system is increased.

The invention discloses a method for reducing the PAPR of an OFDM system through an improved SLM algorithm and relates to an OFDM technology. The method for reducing the PAPR of the OFDM system through the improved SLM algorithm aims to solve the problem that the system error rate of an existing non-sideband transmission SLM algorithm is high, and includes the first step of determining a frequency domain data vector of an OFDM signal, the second step of processing the input vector X through the improved SLM algorithm, the third step of carrying out IFFT on obtained D paths of independent output vectors S(d) to obtain D paths of time-domain signals, the fourth step of selecting and sending the path of signal with the minimum PAPR value, the fifth step of carrying out FFT on the received D paths of signals by a receiving end, the sixth step of carrying out module picking on the obtained D paths of signals after FFT, the seventh step of estimating out which path of signal is emitted by an emitting end and the eighth step of recovering original signal information. The method is applied to the field of wireless communications.

The invention discloses a signal peak-to-average ratio reduction method for an orthogonal frequency division multiplexing (OFDM) system. A peak-to-average ratio is reduced by combining a constellation extension method and null sub-carriers. Regulation is performed on data sub-carriers according to constellation extension rules. Frequency domain filtering is performed on the null sub-carriers. In the method, amplitude-prelimited signal noises are processed to generate a peak cancellation vector in ways of regulating data on the data sub-carriers according to the constellation extension rules, performing a frequency domain filtering operation on the null sub-carriers, reserving noises of a null sub-carrier part and zero-setting the noises of a data sub-carrier part to completely transfer the noises to areas of the null sub-carriers and constellation extension without influencing judgment in a constellation diagram of a receiver to further reduce the peak-to-average ratio of a signal. By the method, the peak-to-average ratio of the OFDM signal can be effectively reduced, and iteration times can be reduced.

The invention discloses a method and a device for processing peak-to-mean ratio. The method for processing peak-to-mean ratio comprises the following steps of: firstly, determining a truncation signal of a baseband signal, the peak value of which is higher than or equal to the preset peak value threshold; secondly, determining a peak extinction coefficient of the baseband signal according to the truncation signal; and thirdly, processing the baseband signal in the Newton iteration method according to the peak extinction coefficient and making the peak value of the baseband signal lower than the peak value threshold. By adopting the invention, the quality of the signal is improved, the complexity of the whole system is reduced and no negative effect occurs.

The invention discloses a method for reducing peak-to-average ratio, which comprises the steps: (a) determining off-peak kernel sequence: kernel(i), i is an element of a set [1, N] by utilizing a tone preservation algorithm according to the position information of reserved subcarrier; (b) determining power peak value val in current off-peak sequence to be processed and determining the testing value beta(i) according to beta(i) = val- target*const*Theta< j*Theta(val) >, wherein, the target refers to target power value of off-peak, the constant refers to the step size of off-peak, Theta(val) refers to phase angle corresponding to the power peak value val; (c) carrying out cyclic shift to the off-peak kernel sequence: kernel(i) to obtain an iteration off-peak kernel sequence: kernel'(i); and (d) determining result sequence of off-peak process: data' (i). By adopting the method and the device disclosed by the invention, peak-to-average ratio in OFDM system can be effectively reduced.

The invention discloses an OFDM (Orthogonal Frequency Division Multiplexing) peak-to-average power ratio lowering method based on constellation linear expansion, which has the advantages of capability of greatly lowering a peak-to-average ratio, small influence on a system error rate, no need of transmitting sideband information, no need of changing a receiving end, low calculation amount and low hardware implementation cost. The method comprises the following steps of: (1) mapping binary data to be transmitted into a constellation point; (2) establishing a constellation expansion OFDM signal peak-to-average ratio lowering model; (3) training a constellation proportional factor ki; and (4) performing expansion changing on the constellation point by using the trained constellation proportional factor ki to obtain constellation mapping with a low peak-to-average ratio, i.e., multiplying a frequency domain complex signal of bearing information by the proportional factor for performing IFFT (Inverse Fast Fourier Transform) calculation to obtain an output time domain complex signal.

The present invention relates to a method for reducing the peak-to-average ratio in an OFDM system. The method comprises the steps of: step 1, rapid inverse Fourier transforming a modulation signal that needs to be transmitted, acquiring a first time-domain signal collection; step 2, searching in the first time-domain signal collection for multiple time-domain signals of powers that satisfy a threshold and time-domain positions of the time-domain signals when at maximum power; step 3, transmitting a frequency-domain auxiliary signal in a determined subcarrier, and reversely adjusting second time-domain signals of the auxiliary signal at the time-domain positions of first time-domain signals when at maximum power, where the first time-domain signals are the time-domain signals of the greatest power among the multiple time-domain signals; and, step 4, adding the adjusted second time-domain signals of the auxiliary signal to the multiple first time-domain signals to reduce the peak-to-average ratio of the modulation signal. The method allows for implementation of a reduction in the peak-to-average ratio of the modulation signal in the OFDM system insofar that power consumption and the amount of computations are reduced.

The invention provides a signal modulation method, device and system. The method comprises the steps that a sending end carries out periodic extension on a first frequency domain signal acquired by converting to-be-sent data into a frequency domain; the sending end uses a preset frequency domain filter to carry out filtering processing on the first frequency domain signal after the periodic extension to acquire a second frequency domain signal; the sending end maps the second frequency domain signal onto a target subcarrier used for transmitting the second frequency domain signal; and the sending end transforms the second frequency domain signal mapped onto the target subcarrier onto a time domain via inverse Fourier transform to acquire a time domain signal and modulates a baseband signal corresponding to the time domain signal onto the carrier to be sent. A peak-to-average ratio of the sending signal and the complexity of channel estimation of a receiving end can be reduced.

An embodiment of the invention discloses an antenna calibration method and a base band unit, belongs to the field of wireless communication and is used for improving the accuracy of antenna calibration. According to the scheme of the antenna calibration method and the base band unit, at least two times of calibration processes are performed in a current calibrating period after a calibrating signal to be sent is generated, and during every calibration process, the calibrating signal is firstly needed to be subjected to channel difference compensation according to a phase compensation coefficient and then sent by a sending channel. Therefore, the signal peak-to-average ratio is reduced and the accuracy of the final calibration result can be improved.

The invention discloses a quasi-lossless compression method based on corrected OFDM sub-carriers. The method comprises the steps that at a sending end, an information source sequence is subjected to constellation map mapping and then is modulated to the sub-carriers through conjugate antisymmetry for IFFT to a time domain; a sub sequence 1 is extracted out through a down sampling device, data of the rest of sampling points are used as a sub sequence 2 and subjected to the companding process; at a receiving end, each received OFDM symbol sequence is divided into two sub sequences, and the sub sequence 2 is subjected to de-companding; every two sub sequences are combined to form a complete OFDM time-domain signal which is transformed to a frequency domain through FFT and recovered on a constellation map; the signal is transformed to the time domain through IFFT, a sub sequence 3 is extracted out through the down sampling device, and the sub sequence 3 and the sub sequence 1 are subjected to subtraction to obtain a time-domain signal deviation value; the deviation value is subjected to FFT, and through judgment of magnitude of the deviation value and a preset threshold value, the sub-carriers with constellation point deviation are determined; the deviation values of constellation mapping points are compensated on corresponding sub-carriers and transformed to the time domain through the IFFT.

This invention provides one single load wave and frequency address system emission device, receive device and its method based on multiple sub filter set, which comprises the following steps: through multiple sub filter set, the whole system wide band is divided into several crossing thin band signal channel by use of signal load transmission pattern; each user can align one or more sub signal channels according to transmission speed; each user adopts several sub channel with continuous lining or discrete sequence.