Frequency offset estimation method, device, communication device and storage medium

A frequency offset estimation device, applicable to a signal receiving end, wherein the signal receiving end is in communication with a signal sending end, and the device comprises:

• an acquisition module, configured to acquire a main peak and a secondary peak of a PRACH signal when detecting that an access signal is in the PRACH signal sent by the signal sending end, wherein the PRACH signal is composed of a preset number of identical leader sequences;
• a first determination module, configured to calculate a ratio of a peak value of the main peak to a peak value of the secondary peak and determine a first frequency offset according to the ratio and a preset subcarrier interval;
• a compensation module, configured to perform a frequency offset compensation on the PRACH signal according to the first frequency offset, to obtain a compensation sequence after the frequency offset compensation;
• a second determination module, configured to calculate a frequency offset between the compensation sequence and the leader sequences, to obtain a second frequency offset, so as to estimate a time delay of the access signal according to the second frequency offset;
• and
• an estimation module configured to acquire a position of the main peak, and estimate a time delay of the access signal according to the position of the main peak and the second frequency offset, wherein
• according to a main peak point m′ and a number {circumflex over (l)} of folds in integral folds of the frequency offset, a time delay position k is derived by calculation using a following formula, the access signal is expressed as:
• r
• ⁡
• (
• n
• )
• =
• e
• j
• ⁢
• 2
• ⁢
• πΔε
• ⁢
• n
• N
• ×
• A
• ⁢
• e
• -
• j
• ⁢
• π
• ⁢
• n
• ⁡
• (
• 1
• +
• μ
• ′
• )
• N
• ⁢
• z
• ⁢
• c
• μ
• ′
• (
• n
• -
• κ
• )
• +
• w
• ⁡
• (
• n
• )
• a correlation peak is expressed as:
• R
• ⁡
• (
• m
• ,
• Δ
• ⁢
• f
• )
• =
• ∑
• n
• =
• 0
• N
• -
• 1
• r
• ⁡
• (
• n
• )
• ⁢
• s
• *
• (
• n
• -
• m
• )
• wherein if the number of folds of the frequency offset is not an integer, the peak point of the above formula m′=k, and the searched peak position m′ is a user time delay k;
• and if the number of folds of the frequency offset is an integer;
• the main peak point m′ and an actual time delay point k satisfy MOD(μ′{circumflex over (l)}+κ,N)=m′;
• wherein r(n) is the access signal, Δε is a frequency offset of the signal, Δε=Δf/fs, fs is a sampling rate, Δf is a frequency offset,
• A
• =
• 1
• N
• [
• ∑
• k
• =
• 0
• N
• -
• 1
• ZC
• μ
• (
• k
• )
• ]
• ,
• w(n) is noise with a mean value of 0 and a variance of σ2, μ is a root value, k represents an index value of a ZC sequence, N represents a length of a time domain sequence, n represents an index of the time domain sequence, and μ′ is dual to the root value μ.