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 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 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.