51results about How to "Expand the range of frequency offset estimation" patented technology

The invention relates to a frequency offset tracking and compensating method and device. The method includes: performing frequency correction on a received burst signal with a current frequency offset estimated value; performing channel estimation and equalization processing on the burst signal after frequency correction, and obtaining a channel estimation result and an equalized symbol; calculating an offset phase position based on the channel estimation result or the equalized symbol; converting the offset phase position to a frequency offset increment, and accumulating the frequency offset increment and the current frequency offset estimated value to update the current frequency offset estimated value; updating a CRC result in a preset CRC buffer memory, and CRC result being obtained by performing decoding processing on the equalized symbol; and if predetermined conditions are satisfied, performing negation operation on the current frequency offset estimated value, and the predetermined conditions including that totally wrong decoding is judged based on all CRC results in the CRC buffer memory, and the current frequency offset estimated value is greater than a preset threshold value. The technical scheme can easily and effectively expand a frequency offset tracking range, so as to deal with large frequency offset or a frequency offset jump.

The invention discloses an ASM system receiving frequency deviation estimation realization method of a ship VDES system. The method comprises the following steps: performing I and Q orthogonal frequency mixing on an intermediate-frequency signal, respectively outputting an in-phase component I and an orthogonal component Q; respectively performing extraction and low-pass filtering on the in-phase component I and the orthogonal component Q, performing the phase discrimination processing on the in-phase component I and the orthogonal component Q after the low-pass filtering, outputting the phase discrimination error; caching the phase discrimination error in a RAM to perform the variable rate processing so as to adapt to the FFT rapid calculation; performing the maximum peak detection on the output data of the FFF calculation; finding out the subscript n of a maximum value, computing out an estimated frequency deviation fd; compensating the computed frequeny deviation fd to the nominal frequency f0, namely, the nominal frequency at this time is changed as f0+fd. By using the method disclosed by the invention, the accurate estimation can be performed by starting from any moment under a situation of not foreseeing bit synchronization information, and the frequency deviation range is large, and the estimation precision is high; furthermore, the method adopts the maximum peak detection judgment which is more suitable for the low signal-to-noise signal estimation in comparison with the threshold judgement detection method.

The present invention provides a frequency offset estimation method and system for a narrowband physical uplink shared channel of a wireless comprehensive tester. The frequency offset estimation method includes the following steps: step S1, using a narrowband demodulation reference signal to perform frequency offset estimation; step S2, obtaining The initial maximum frequency offset value; step S3, calculate the phase value of the time domain data of the local narrowband demodulation reference signal; step S4, carry out frequency offset compensation to the time domain signal of the received narrowband demodulation reference signal, and calculate the frequency The phase value of the time-domain data of the narrowband demodulation reference signal after offset compensation; step S5, calculate the phase difference between the received narrowband demodulation reference signal and the local narrowband demodulation reference signal; step S6, calculate the phase difference Its variance; Step S7, calculate the final estimated value of frequency offset by the minimum variance value of the variance. The invention enables the wireless comprehensive tester to greatly expand the range of frequency offset estimation on the basis of ensuring the accuracy of frequency offset estimation.

The invention discloses a new synchronous combination method of an OFDM system, relating to communication technical field and aimed at realizing synchronization of an OFDM system. The method includes the following processes: OFDM signals r(n) are received; symbol synchronization and fractional frequency offset(FFO) estimation and compensation are realized through existing ML synchronization algorithm in time domain; fast Fourier transform is carried out to the signals so as to realize transformation from time domain to frequency domain; based on the transformation, integer frequency offset(IFO) estimation is carried out according to the offset position of a virtual carrier; integer frequency offset compensation is done in frequency domain; a Flag marker bit is estimated; if Flag is equal to 0, IFO estimation and compensation in frequency domain will be carried out repeatedly; if Flag is equal to 1, combined estimation and compensation in time domain and frequency domain synchronously to the OFDM system are carried out and precise sync signal Xk` is outputted. The new synchronous combination method is applicable to digital video broadcasting (DVB) systems, digital audio broadcasting (DAB) systems as well as wireless communication systems, such as 802.11a, and 802.16.

The invention discloses a multicarrier synchronization method and system of a nested recurrent PN sequence. According to the method, a carrier frequency offset estimation step and a frequency offset correction step are carried out successively, in the carrier frequency offset estimation step, the separated nested recurrent PN sequence is processed; and in the frequency offset correction step, the carrier frequency offset of a received signal is corrected. According to technical schemes of the invention, the method and device can be applied to the digital communication fields with low signal to noise ratio transmission and severe clutter interference, as ground wireless communication and satellite and power line communication.

The invention discloses a frequency offset and phase offset estimation method in a single carrier interleaved frequency division multiple access (SC-IFDMA) system and mainly solves the problem that inthe prior art, the estimation precision is low under an environment with relatively poor channels. The method comprises the application steps of generating transmitting data; arriving at a receivingend by the transmitting data through the channels; extracting data of each single carrier interleaved frequency division multiple access symbol of the receiving end; carrying out frequency offset estimation through utilization of repeated data and through adoption of an iteration method; carrying out frequency offset correction on received data through estimated frequency offset; demapping frequency offset corrected signals through subcarriers to obtain transform domain data; ordering the transform domain data according to an ordering rule and extracting phases of the first K pieces of data; calculating difference values of the phases of the K pieces of data and initial phases of symbols of quadrants in which the data is located; and averaging the obtained K difference values to obtain a final phase offset estimation value. According to the method, the estimation precision is high, the frequency offset and phase offset can be effectively estimated, and the method can be used for correcting rotation of a signal constellation diagram in the single carrier interleaved frequency division multiple access system.

The present invention provides a large frequency offset estimation method in a 5G NR system, including: extracting DMRS signals at the three symbol positions of the SSB block; respectively performing frequency-domain channel response measurement on the DMRS signals at the first and second symbol positions ; The frequency domain channel response is smoothed and denoised and pruned according to multipath energy; the first phase difference and the first frequency offset are estimated; the DMRS signal at the 2nd and 3rd symbol positions is tried to compensate for the frequency offset; the compensation is obtained The DMRS signal repeats the steps S2-S4 to obtain the second frequency offset, and obtains the frequency offset according to the second frequency offset. The present invention also provides a large frequency offset estimation device in a 5G NR system. The large frequency offset estimation method of the present invention can complete the estimation of the frequency offset greater than the subcarrier spacing within one SSB signal block in the high-speed rail environment, which can improve the frequency offset estimation range and estimation accuracy, and further improve 5G NR communication under the high-speed rail quality.

An OFDM frequency deviation estimating method based on allocycle adjacent structure includes designing an OFDM circulation prefix of allocycle adjacent structure, adding designed circulation prefix at front end of OFDM effective data to form an OFDM symbol being sent out through channel, carrying out time synchronization and frequency synchronization at receiving end according to OFDM symbol.