Distance correction codeword detection and time migration estimation method and system

Abstract

The invention discloses a method for Ranging code word detection and a time migration estimation method and a system thereof. In the method, frequency domain Ranging data and all possible local code words with time migration compensation are correspondingly multiplied; the multiplied results are added for the sum and impression taking, and the calculated peak value at a time are stored; the maximum peak value is selected from all the stored peak values; the maximum peak value is compared with a first threshold; if the maximum peak value is less than the first threshold, the detection is finished; if not, all the stored peak values are compared with a second threshold; the local code words which are corresponding to the peak values greater than the second threshold serve as the Ranging code words transmitted by active users; the time migration estimation is carried out according to the compensation phase position which is corresponding to the peak values greater than the second threshold. By the method, the dependence on interference power is eliminated, thus avoiding miss rate or false alarm phenomenon caused by inaccurate interference power estimation, achieving the purpose that the accurate detection still can be carried out when in multiuser, and simultaneously increasing the precision of the time migration estimation.

Description

technical field [0001] The present invention relates to the field of data transmission in mobile communication, in particular, to the distance correction (Ranging) processing technology in an Orthogonal Frequency Division Multiplexing (OFDM) system, especially to Ranging code word detection and time Offset estimation method and system. Background technique [0002] At present, mobile communication has become a hot technology with the greatest development potential and the broadest market prospect in the field of contemporary communication, and Orthogonal Frequency Division Multiplexing (OFDM for short) technology is one of the hot technologies in mobile communication technology research. . [0003] Orthogonal Frequency Division Multiplexing (OFDM) is a special multi-carrier transmission scheme, which can be regarded as a modulation technique as well as a multiplexing technique. The basic idea is to divide a given channel into several orthogonal sub-channels in the frequenc...

AI Technical Summary

Problems solved by technology

In this method, the threshold 1 is related to the noise power, and the estimation of the noise power is usually not accurate enough, so it may cause missed detection or false alarm; in the case of false alarm or missed detection, the codeword correlation matrix is ​​used to adjust the possible code When the power corresponding to the code word is used, due to the existence of false alarms or missed detections, the correlation matrix of the code word is not accurate enough, which leads to the failure of the adjustment.

In addition, this method estimates the symbol offset based on the phase difference between adjacent subcarriers in the tile. When there are more than one user, the estimated time offset is inaccurate due to phase ambiguity at the receiving end.

[0010] Through simulation, it is found that the false alarm probability of the algorithm is relatively high, and the accuracy of time offset estimation is not high, and when the number of users increases, the performance of the algorithm decreases rapidly

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