44results about How to "Improve frequency offset estimation accuracy" patented technology

The invention relates to a frequency offset estimation method and system for a burst-mode signal. The method comprises the steps of extracting pilot frequency information of each segment in a received burst frame to obtain at least two segments of initial pilot frequency sequences; according to the pilot frequency information of each segment of initial pilot frequency sequence and standard pilot frequency information, generating target pilot frequency sequences; carrying out phase angle obtaining processing on the target pilot frequency sequences to obtain phase angle sequences; segmenting the phase angle sequences and setting a spacing between each two adjacent phase angle sequences; and according to a difference of two adjacent phase angle values in the phase angle sequences, calculating a series of frequency offset estimated values. According to the scheme of estimating the frequency offset of the burst-mode signal, which is provided by the invention, under the condition that each segment of pilot frequency sequence in a burst sequence in short burst communication is relatively short, by processing each segment of pilot frequency sequence, frequency offset estimation can be carried out through utilizing multiple segments of pilot frequency information, and each segment of pilot frequency sequence is not requested to have an equal length, and thus, a frequency offset value of the short burst frame can be accurately estimated, and frequency offset estimation accuracy under the condition of a low signal-to-noise ratio can be improved.

The invention discloses a synchronization method of an FBMC system based on a zero autocorrelation code. The synchronization method comprises the following steps that 1) a transmitter and a receiver are identical in construction and have symbols of the zero autocorrelation features, and the transmitter constructs synchronization symbols through the symbols and transmits the synchronization symbols; and 2) the receiver uses the same zero autocorrelation code symbols, calculates a real-time measurement value and a real-time threshold, judges the size of the two values and determines a timing point, and calculates the frequency offset error by using the measurement value of the timing point. A timing metric function can be constructed by the zero autocorrelation code generated by the FBMC system so that the system data transmission efficiency can be enhanced. Compared with the conventional methods, the synchronization method has higher estimation accuracy and is insensitive to complex channels so as to enhance the communication reliability.

The invention relates to a frequency synchronization method based on joint estimation carrier of frequency offset, belonging to the technical field of wireless mobile communication. The frequency synchronization method comprises the steps of: carrying out coarse frequency synchronization by using a short training field so as to correct integer frequency offset and carrying out frequency offset compensation on the basis of a coarse frequency synchronization result; by using a signal subjected to frequency offset compensation and a long training field, in combination with a segmentation related algorithm, carrying out frequency estimation to obtain a carrier frequency offset 1; obtaining a carrier frequency offset 2 on the basis of an MMSE (Minimum Mean Square Error) criterion; further obtaining a carrier frequency offset 3 on the basis of a mean square error criterion, and giving frequency synchronization results in different wireless channel environments; and finally, on the basis of the frequency synchronization results, carrying out frequency offset correction on a received signal. According to the frequency synchronization method, the synchronization mean square error of a wireless system is greatly lowered and the synchronization precision is effectively improved.