Fractional frequency offset estimation method based on cyclic prefixes

Abstract

The invention discloses a CP-based frequency offset estimation method of an SC-FDMA system, for mainly solving the problem of poor anti-noise performance in the prior art. The method comprises the following implementation steps: (1) extracting cyclic prefixes of all single carrier frequency division multiple access SC-FDMA symbols and data parts corresponding to the cyclic prefixes on a receiving end to acquire K {CP, Data} pairs; (2) estimating frequency offset values corresponding to the SC-FDMA symbols according to the maximum likelihood estimation criterion to acquire a frequency offset value sequence corresponding to all SC-FDMA symbols; (3) calculating an arithmetic mean delta fmean of the frequency offset value sequence; (4) using the delta fmean as an actual frequency offset value delta f, and calculating Gauss weighting coefficients corresponding to the frequency offset values; and (5) calculating a weighted mean according to the frequency offset values and the weighting coefficients of the frequency offset values to serve as a system frequency offset estimation value. The method disclosed by the invention is high in estimation precision and low in implementation complexity, can realize good work in high-speed moving scenes and low signal to noise ratio, and can be applied to orthogonal frequency division multiple access systems and single carrier frequency division multiple access systems.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to a method for estimating a fractional multiple frequency offset, which can be used in an Orthogonal Frequency Division Multiple Access OFDMA system and a Single Carrier Frequency Division Multiple Access SC-FDMA system. Background technique [0002] OFDMA technology not only has a high spectrum utilization rate, but also has a good ability to resist frequency selective fading in multipath channel scenarios, but its peak-to-average ratio PAPR is high, making it difficult for mobile terminals to support such power characteristics. SC-FDMA technology has the same advantages of high spectrum utilization and low complexity as OFDMA technology, and its low peak-to-average ratio PAPR can meet the requirements of general systems. Therefore, the uplink of many wireless transmission modes uses SC -FDMA technology replaces OFDMA technology, such as the SC-FDMA technology us...

AI Technical Summary

Problems solved by technology

However, since the cyclic prefix CP sequence is inherently short, it is impossible to avoid the influence of noise and other uncertain factors on the performance of frequency offset estimation

Due to the randomness of noise interference, the frequency offsets calculated by different SC-FDMA symbols are affected to varying degrees. It can be considered that there are good and bad frequency offset estimates, so directly calculating the arithmetic mean of these frequency offsets cannot maximize To resist the influence of noise, resulting in low estimation accuracy

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