Frequency offset estimation method and device based on 5G demodulation reference signal

Abstract

The invention provides a frequency offset estimation method and device based on a 5G demodulation reference signal, and the method comprises the steps: determining a first frequency offset estimation value set according to a frequency domain receiving sequence and a local sequence of a DMRS symbol configured by a physical layer channel; eliminating frequency offset estimation values with absolute values greater than a preset threshold value in the first frequency offset estimation value set to obtain a second frequency offset estimation value set; performing frequency offset compensation on the DMRS symbol by using each frequency offset estimation value in a second frequency offset estimation value set to obtain a frequency offset compensation sequence of each frequency offset estimation value on the DMRS symbol; and performing correlation operation on the frequency offset compensation sequence of the DMRS symbols and the local sequence of the DMRS symbols by the frequency offset estimation values to obtain correlation values, and taking the frequency offset estimation value corresponding to the maximum correlation value as a frequency offset estimation result. The method effectively improves the frequency offset estimation range, enables the system to support larger Doppler frequency offset tracking and compensation, and further supports larger relative movement speed of a receiving end and a transmitting end.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a frequency offset estimation method and device based on a 5G demodulation reference signal. Background Art

[0002] In 5G high-speed mobile application scenarios, such as low-orbit satellite communications, ground-to-air communications, and 5G high-speed rail communications based on the 5G system, the Doppler frequency deviation of the system will quickly decrease from a positive value to a negative value due to the Doppler effect when the high-speed moving terminal approaches and moves away from the base station. The frequency deviation change rate is large, and in this process, it is often necessary to track the frequency deviation in real time and perform frequency deviation compensation. In addition, due to the relatively high-speed movement of the terminal and the base station, the Doppler frequency deviation range of the system is large. Overall, in 5G high-speed mobile application scenarios, the system needs to support both a larger frequency deviation estimation range and a larger frequency deviation change rate.

[0003] The existing frequency offset estimation methods for 5G OFDM (Orthogonal Frequency Division Multiplexing) systems often combine the PSS (Primary Synchronization Signal) and SSS (Secondary Synchronization Signal) in the SSB (Synchronization Signal Block) for joint estimation, using frequency domain shift and signal correlation to estimate integer frequency offsets, and using the phase difference between the transmission intervals before and after the signal to estimate fractional frequency offsets. However, in actual systems, SSB is configured according to a period. When the configuration period is large, it is difficult to track the frequency offset changes of the channel in real time using SSB. In addition, since SSB is configured in the 5G downlink broadcast channel, the traditional solution for frequency offset estimation using SSB is difficult to apply to the 5G uplink channel and has a limited scope of application.

[0004] In addition, the existing scheme for estimating frequency offset based on the cyclic prefix of OFDM symbols is limited by the short 5G cyclic prefix data and is susceptible to noise interference, which reduces the accuracy of frequency offset estimation. Considering that the DMRS (Demodulation Reference Signal) signal is much longer than the cyclic prefix and the density of signal configuration is significantly higher than the SSB signal used for downlink synchronization, the use of DMRS for frequency offset estimation can correct the frequency offset value of the physical layer channel more timely and improve the demodulation performance of the receiver. However, the traditional frequency offset estimation scheme based on the phase difference of the DMRS signal is limited by the time interval between pilot symbols, and the frequency offset estimation range is limited, making it difficult to apply to the large Doppler frequency offset values ​​generated in high-speed mobile scenarios. Summary of the invention

[0005] The present invention provides a frequency offset estimation method and device based on a 5G demodulation reference signal, so as to solve the defect that the frequency offset estimation range based on the DMRS signal phase difference in the prior art is limited and difficult to be applied to a large number of Doppler frequency offset values ​​generated in high-speed mobile scenarios, thereby improving the estimated frequency offset range based on the DMRS method, enabling the system to support a larger Doppler frequency offset estimation range, and also enabling the system's transceiver to support a higher relative mobile speed.

[0006] The present invention provides a frequency offset estimation method based on a 5G demodulation reference signal, comprising:

[0007] Determine a first frequency offset estimation value set of the physical layer channel according to a frequency domain received sequence and a local sequence of a DMRS symbol configured by the physical layer channel;

[0008] Eliminate frequency offset estimation values ​​whose absolute values ​​are greater than a preset threshold in the first frequency offset estimation value set to obtain a second frequency offset estimation value set;

[0009] Perform frequency offset compensation on the DMRS symbol using each frequency offset estimation value in the second frequency offset estimation value set to obtain a frequency offset compensation sequence of the DMRS symbol using each frequency offset estimation value;

[0010] Correlation operation is performed on each frequency offset estimation value in the second frequency offset estimation value set with the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol to obtain a correlation value, and the frequency offset estimation value corresponding to the maximum correlation value is used as the frequency offset estimation result of the physical layer channel.

[0011] According to a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention, a first frequency offset estimation value set of the physical layer channel is determined according to a frequency domain received sequence and a local sequence of a DMRS symbol configured by a physical layer channel, including:

[0012] Determine the frequency domain channel of each DMRS symbol according to the frequency domain reception sequence and the local sequence of the DMRS symbol configured by the physical layer channel;

[0013] Determining a phase difference between the DMRS symbols according to the frequency domain channels of the DMRS symbols;

[0014] The first frequency offset estimation value set is determined according to the phase difference.

[0015] According to a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention, the DMRS symbol includes a first DMRS symbol and a second DMRS symbol, and the first DMRS symbol and the second DMRS symbol correspond to the first and second DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index;

[0016] The first frequency offset estimation value set is determined according to the phase difference by the following formula:

[0017]

[0018] in, is a frequency offset estimation value in the first frequency offset estimation value set, wherein the first frequency offset estimation value set is θ is the phase difference between the first DMRS symbol and the second DMRS symbol, M is 0 or a positive integer, C1 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the second DMRS symbol, and T is the sampling period of the first DMRS symbol and the second DMRS symbol.

[0019] According to a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention, the DMRS symbol includes a first DMRS symbol, a second DMRS symbol and a third DMRS symbol;

[0020] The first frequency offset estimation value set is determined according to the phase difference by the following formula:

[0021]

[0022] wherein the function mod(x,2π) represents the modulo operation of x on 2π, M is 0 or a positive integer, θ1 is the phase difference between the first DMRS symbol and the second DMRS symbol, θ2 is the phase difference between the first DMRS symbol and the third DMRS symbol, C1 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the second DMRS symbol, and C2 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the third DMRS symbol;

[0023] If s(N1)≤π, then r(N1)=s(N1); if s(N1)>π, then r(N1)=s(N1)-2π;

[0024]

[0025] in, is a frequency offset estimation value in the first frequency offset estimation value set, wherein the first frequency offset estimation value set is T is a sampling period of the first DMRS symbol, the second DMRS symbol and the third DMRS symbol.

[0026] According to a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention, when the physical layer channel is configured with 3 DMRS symbols, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the first, second and third DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index;

[0027] In the case where the physical layer channel is configured with 4 DMRS symbols, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the 1st, 2nd and 3rd DMRS symbols, or the 1st, 2nd and 4th DMRS symbols, or the 2nd, 3rd and 4th DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index.

[0028] According to a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention, each frequency offset estimation value in the second frequency offset estimation value set is correlated with the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol to obtain a correlation value, including:

[0029] Dividing the frequency offset compensation sequence corresponding to each frequency offset estimation value in the second frequency offset estimation value set and the local sequence of the DMRS symbol into the same number of segments;

[0030] Performing a correlation operation on each segment of the frequency offset compensation sequence corresponding to each frequency offset estimation value in the second frequency offset estimation value set and a corresponding segment of the local sequence of the DMRS symbol to obtain a correlation value of each segment;

[0031] The correlation values ​​of each segment are added together to obtain the correlation value between the frequency offset compensation sequence corresponding to each frequency offset estimation value in the second frequency offset estimation value set and the local sequence of the DMRS symbol.

[0032] According to a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention, the physical layer channel includes a physical uplink shared channel, a physical uplink control channel, a physical downlink shared channel and a physical downlink control channel.

[0033] The present invention also provides a frequency offset estimation device based on a 5G demodulation reference signal, comprising:

[0034] A frequency offset estimation module, configured to determine a first frequency offset estimation value set of the physical layer channel according to a frequency domain received sequence and a local sequence of a DMRS symbol configured by the physical layer channel;

[0035] A frequency offset updating module, configured to remove frequency offset estimation values ​​whose absolute values ​​are greater than a preset threshold in the first frequency offset estimation value set, to obtain a second frequency offset estimation value set;

[0036] A frequency offset compensation module, configured to perform frequency offset compensation on the DMRS symbol using each frequency offset estimation value in the second frequency offset estimation value set, to obtain a frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol;

[0037] The correlation operation module is used to perform a correlation operation on each frequency offset estimation value in the second frequency offset estimation value set with respect to the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol to obtain a correlation value, and use the frequency offset estimation value corresponding to the maximum correlation value as the frequency offset estimation result of the physical layer channel.

[0038] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a frequency offset estimation method based on a 5G demodulation reference signal as described in any one of the above-mentioned methods is implemented.

[0039] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a frequency offset estimation method based on a 5G demodulation reference signal as described in any one of the above.

[0040] The present invention also provides a computer program product, comprising a computer program, which, when executed by a processor, implements a frequency offset estimation method based on a 5G demodulation reference signal as described in any one of the above.

[0041] The frequency offset estimation method and device based on the 5G demodulation reference signal provided by the present invention effectively improves the frequency offset estimation range by utilizing the autocorrelation of the DMRS symbols configured in the 5G physical layer channel and the 2π periodicity in the phase difference calculation, so that the system supports a larger Doppler frequency offset tracking and compensation, and thus supports a larger relative moving speed of the transceiver. In addition, unlike SSB which is only configured in the 5G downlink channel, DMRS is configured in both the 5G uplink and downlink channels, so it is applicable to both the uplink and downlink physical layer channels configured with DMRS, and has a wide range of applications; the DMRS signal has a higher configuration density in the 5G channel configuration than the SSB signal, so it can track the frequency offset changes more timely, and is suitable for high-mobility communication scenarios such as low-orbit satellite communications, ground-to-air communications, and 5G high-speed railways based on the 5G communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1It is a flow chart of a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention;

[0044] Figure 2 It is a schematic diagram of configuring two DMRS symbols in a physical layer channel in a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention;

[0045] Figure 3 It is a schematic diagram of configuring three DMRS symbols in a physical layer channel in a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention;

[0046] Figure 4 It is a schematic diagram of configuring 4 DMRS symbols in a physical layer channel in a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention;

[0047] Figure 5 It is a flow chart of obtaining a DMRS frequency offset compensation sequence set when a physical layer channel is configured with 4 DMRS symbols in a frequency offset estimation method based on a 5G demodulation reference signal provided by the present invention;

[0048] Figure 6 It is a structural schematic diagram of a frequency offset estimation device based on a 5G demodulation reference signal provided by the present invention;

[0049] Figure 7 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] The physical layer of the 5G mobile communication system mainly adopts OFDM-based waveform modulation technology. In order to realize uplink and downlink data transmission, the 5G physical layer channels are divided according to the functions of uplink and downlink transmission, and define uplink random access channel, uplink shared channel (Physical Uplink Shared Channel, PUSCH), uplink control channel (Physical Uplink Control Channel, PUCCH), downlink broadcast channel, downlink shared channel (Physical Downlink Shared Channel, PDSCH) and downlink control channel (Physical Downlink Control Channel, PDCCH). The corresponding information is transmitted by allocating different time and frequency domain resources to the physical layer channels. For example, the physical uplink shared channel PUSCH can be configured with multiple subcarriers in the frequency domain and multiple OFDM symbols in the time domain for transmitting uplink data and other information. In addition, in order to improve the demodulation performance of the receiver, in addition to the uplink random access channel, other physical layer channels can be configured with DMRS symbols to assist in demodulating data symbols.

[0052] The OFDM modulation waveform is a multi-carrier modulation technology, and its demodulation performance is sensitive to frequency offset. Excessive frequency offset will cause signal interference between multiple carriers and reduce reception performance. The 5G physical layer introduces the synchronization signal block (SSB) in the downlink broadcast channel. The primary synchronization signal (PSS) and secondary synchronization signal (SSS) contained in the SSB can achieve time-frequency synchronization of downlink transmission.

[0053] Combine the following Figure 1 A frequency offset estimation method based on a 5G demodulation reference signal of the present invention is described, comprising:

[0054] Step 101, determining a first frequency offset estimation value set of the physical layer channel according to a frequency domain received sequence and a local sequence of a DMRS symbol configured by the physical layer channel;

[0055] The execution subject of this embodiment is a receiver, which calculates a first frequency offset estimation value set according to a frequency domain reception sequence and a local sequence of a received DMRS symbol and using the 2π periodicity of a phase.

[0056] Step 102, removing frequency offset estimation values ​​whose absolute values ​​are greater than a preset threshold from the first frequency offset estimation value set, to obtain a second frequency offset estimation value set;

[0057] Use the preset threshold f max The frequency offset estimation values ​​in the first frequency offset estimation value set are determined in sequence, and the frequency offset estimation values ​​whose absolute values ​​are greater than the preset threshold value f are eliminated. max The frequency offset estimation value is obtained by using the frequency offset estimation value set of the second frequency offset estimation value set.

[0058] Step 103, performing frequency offset compensation on the DMRS symbol using each frequency offset estimation value in the second frequency offset estimation value set to obtain a frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol;

[0059] Step 104: Correlate the frequency offset estimation values ​​with the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol to obtain correlation values, and use the frequency offset estimation value corresponding to the maximum correlation value as the frequency offset estimation result of the physical layer channel.

[0060] This embodiment effectively improves the frequency offset estimation range by utilizing the autocorrelation of the DMRS symbols configured in the 5G physical layer channel and the 2π periodicity in the phase difference calculation, so that the system supports greater Doppler frequency offset tracking and compensation, and further supports greater relative movement speeds between the transmitter and receiver.

[0061] On the basis of the above embodiment, in this embodiment, according to the frequency domain received sequence and the local sequence of the DMRS symbol configured by the physical layer channel, a first frequency offset estimation value set of the physical layer channel is determined, including:

[0062] Determine the frequency domain channel of each DMRS symbol according to the frequency domain reception sequence and the local sequence of the DMRS symbol configured by the physical layer channel;

[0063] Determining a phase difference between the DMRS symbols according to the frequency domain channels of the DMRS symbols;

[0064] The first frequency offset estimation value set is determined according to the phase difference.

[0065] The number of DMRS symbols configured in the physical layer channel is different, and the method for determining the first frequency offset estimation value set according to the phase difference is different. In this embodiment, the number of DMRS symbols is not less than 2.

[0066] On the basis of the above embodiment, the DMRS symbol in this embodiment includes a first DMRS symbol and a second DMRS symbol, and the first DMRS symbol and the second DMRS symbol correspond to the first and second DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index;

[0067] like Figure 2As shown, if the physical layer channel is configured with 2 DMRS symbols, namely the first DMRS symbol and the second DMRS symbol, the frequency domain channels of the first DMRS symbol and the second DMRS symbol are estimated according to the frequency domain reception sequence and the local sequence of the DMRS symbol. According to the frequency domain channels of the first DMRS symbol and the second DMRS symbol, the phase difference θ between the two DMRS symbols is calculated. According to the phase difference θ, the first frequency offset estimation value set is calculated by the following formula:

[0068]

[0069] in, is a frequency offset estimation value in the first frequency offset estimation value set, wherein the first frequency offset estimation value set is θ is the phase difference between the first DMRS symbol and the second DMRS symbol, M is 0 or a positive integer, C1 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the second DMRS symbol, and T is the sampling period of the first DMRS symbol and the second DMRS symbol.

[0070] On the basis of the above embodiment, if the physical layer channel is configured with 3 or 4 DMRS symbols, 3 DMRS symbols are used for frequency offset estimation, that is, the DMRS symbols in this embodiment include a first DMRS symbol, a second DMRS symbol and a third DMRS symbol;

[0071] According to the frequency domain received sequence and local sequence of the DMRS symbol, the frequency domain channels of the first DMRS symbol, the second DMRS symbol, and the third DMRS symbol are estimated. The phase difference θ1 is calculated according to the frequency domain channels of the first DMRS symbol and the second DMRS symbol, and the phase difference θ2 is calculated according to the frequency domain channels of the first DMRS symbol and the third DMRS symbol. According to the phase differences θ1 and θ2, the first frequency offset estimation value set is calculated by the following formula:

[0072]

[0073] wherein the function mod(x,2π) represents the modulo operation of x on 2π, M is 0 or a positive integer, θ1 is the phase difference between the first DMRS symbol and the second DMRS symbol, θ2 is the phase difference between the first DMRS symbol and the third DMRS symbol, C1 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the second DMRS symbol, and C2 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the third DMRS symbol;

[0074] If s(N1)≤π, then r(N1)=s(N1); if s(N1)>π, then r(N1)=s(N1)-2π;

[0075]

[0076] in, is a frequency offset estimation value in the first frequency offset estimation value set, wherein the first frequency offset estimation value set is T is a sampling period of the first DMRS symbol, the second DMRS symbol and the third DMRS symbol.

[0077] In step 102, the frequency offset estimation value set whose absolute value is greater than a preset threshold value f max The remaining frequency offset estimation values ​​constitute the second frequency offset estimation value set Wherein L represents the number of elements in the second frequency offset estimation value set.

[0078] In step 103, each element in the second frequency offset estimation value set is used Perform frequency offset compensation on the jth DMRS symbol in the physical layer channel to obtain the sequence u (i,j) . Wherein, j = 1, 2, ..., P, and P represents the number of DMRS symbols configured for the physical layer channel.

[0079] The frequency offset estimation value is used to compensate the frequency offset sequence u of the DMRS symbol. (i,j) , according to the symbol index from low to high, it is spliced ​​into a frequency offset compensation sequence v (i) =(u (i,1) ,u (i,2) ,…,u (i,P) ). Sequence v (i) (i=1,2,..,L) constitutes a DMRS frequency offset compensation sequence set {v (1) ,v (2) ,…,v (L)}.

[0080] Based on the above embodiments, in this embodiment, Figure 3 As shown, in the case where the physical layer channel is configured with 3 DMRS symbols, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the first, second and third DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index;

[0081] like Figure 4As shown, in the case where the physical layer channel is configured with 4 DMRS symbols, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the first, second and third DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index, such as Figure 4 (b) in ; or the 1st, 2nd and 4th DMRS symbols, such as Figure 4 (a) in ; or the 2nd, 3rd and 4th DMRS symbols, such as Figure 4 (c) in .

[0082] On the basis of the above embodiments, in this embodiment, the frequency offset estimation values ​​are correlated with the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol to obtain a correlation value, including:

[0083] Dividing the frequency offset compensation sequence corresponding to each frequency offset estimation value and the local sequence of the DMRS symbol into the same number of segments;

[0084] Performing a correlation operation on each segment of the frequency offset compensation sequence corresponding to each frequency offset estimation value and a corresponding segment of the local sequence of the DMRS symbol to obtain a correlation value of each segment;

[0085] The correlation values ​​of each segment are added together to obtain the correlation values ​​of the frequency offset compensation sequence corresponding to each frequency offset estimation value and the local sequence of the DMRS symbol.

[0086] like Figure 5 As shown, in step 104, the local sequence of each DMRS symbol in the physical layer channel is concatenated from low to high according to the symbol index into a local sequence w=(w (1) ,w (2) ,…,w (P) ), where w (j) (j=1, 2, ..., P) represents the local sequence of the j-th DMRS symbol.

[0087] The frequency offset compensation sequence set {v (1) ,v (2) ,…,v (L)} for each sequence v (i) and the DMRS local sequence w, respectively divided into Q segments, to obtain And w=(w1,w2,…,w Q ),in, and w q They are v (i) And the qth segment of w, i=1,2,..,L, q=1,2,…,Q.

[0088] will sequence With w q Perform autocorrelation operation to obtain the autocorrelation value And find the sum of the autocorrelation values ​​of the Q segment Where i = 1, 2, .., L, and thus the autocorrelation value set {R (1) ,R (2) ,…,R (L)}.

[0089] Determine the autocorrelation value set {R (1) ,R (2) ,…,R (L)} corresponds to the index i of the largest * Among them, i * ∈{1,2,..,L}. According to index i * , select the second frequency offset estimate set The i-th * Elements Output as frequency offset estimation result.

[0090] On the basis of the above embodiments, the physical layer channels in this embodiment include a physical uplink shared channel, a physical uplink control channel, a physical downlink shared channel and a physical downlink control channel.

[0091] The step of determining the phase difference between the DMRS symbols according to the frequency domain channels of the DMRS symbols comprises:

[0092] If the physical layer channel is configured with 2 DMRS symbols, let the channel estimation result of the first DMRS symbol be The channel estimation result of the second DMRS symbol is K is the number of DMRS frequency domain subcarriers; according to the channel estimation result H (1) and H (2) , calculate the phase difference Function y=angle(x) represents the phase of complex number x, and the value range of angle(x) is (-π,π];

[0093] If the physical layer channel is configured with 3 DMRS symbols, let the channel estimation result of the first DMRS symbol be The channel estimation result of the second DMRS symbol is The channel estimation result of the third DMRS symbol is According to the channel estimation result H (1) and H (2) , calculate the phase difference According to the channel estimation result H (1) and H (3) , calculate the phase difference

[0094] If the physical layer channel is configured with 4 DMRS symbols, let the channel estimation result of the first DMRS symbol be The channel estimation result of the second DMRS symbol is The channel estimation result of the third DMRS symbol is The channel estimation result of the 4th DMRS symbol is The phase differences θ1 and θ2 can be calculated in one of the following three ways.

[0095] Method 1: Based on the channel estimation result H (1) and H (2) , calculate the phase difference According to the channel estimation result H (1) and H (4) , calculate the phase difference

[0096] Method 2: Based on the channel estimation result H (1) and H (23) , calculate the phase difference According to the channel estimation result H (1) and H (3) , calculate the phase difference

[0097] Method 3: Based on the channel estimation result H (2) and H (3) , calculate the phase difference According to the channel estimation result H (2) and H (4) , calculate the phase difference

[0098] For example, when determining the first frequency offset estimation value set according to the phase difference, if the physical layer channel is configured with 2 DMRS symbols, let the phase difference M takes the value of 2, the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the second DMRS symbol is C1=4384, and the sampling period is Second;

[0099] Calculate the initial frequency offset estimate N1=0,±1,±2, the first frequency offset estimation value set can be obtained as

[0100] If the physical layer channel is configured with 3 or 4 DMRS symbols, the phase difference M takes the value of 2, the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the second DMRS symbol is C1=21920, the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the third DMRS symbol is C2=39456, and the sampling period is Second;

[0101] calculate Then s(-2) = 3.9270, s(-1) = 5.1836, s(0) = 0.1571, s(1) = 1.4137, s(2) = 2.6704;

[0102] Calculate r(N1) based on s(N1). If s(N1)≤π, then r(N1)=s(N1); if s(N1)>π, then r(N1)=s(N1)-2π, then r(-2)=0.7854, r(-1)=2.0420, r(0)=0.1571, r(1)=1.4137, r(2)=2.6704;

[0103] The initial frequency offset estimation value is calculated according to θ1, C1, C2, r(N1), N1=0,±1,±2 The first frequency offset estimation value set is obtained as:

[0104]

[0105] When solving the second frequency offset estimation value set using the preset threshold, let the frequency offset threshold f max =10kHz, the first frequency offset estimation value set is {-10.12kHz, -3.89kHz, 0.78kHz, 7.01kHz, 13.24kHz}, then the element with the absolute value greater than f in the first frequency offset estimation value set is max The elements of are removed, and the remaining elements form the second frequency offset estimation value set Available

[0106] When solving the DMRS frequency offset compensation sequence set by using the second frequency offset estimation value set, let the second frequency offset estimation value set

[0107] If the physical layer channel is configured with 2 DMRS symbols, the frequency offset estimation value is used Perform frequency offset compensation on two DMRS symbols to obtain the compensation sequence u of the first DMRS symbol. (1,1) , the compensation sequence u of the second DMRS symbol (1,2) ; Sequence u (1,1) 、u (1,2) Splice into a sequence v (1) =(u(1,1) ,u (1,2) ). Similarly, using the frequency offset estimate The available sequence v (2) ; Using the frequency offset estimate The available sequence v (3) ; Sequence v (1) 、v (2) 、v (3) Constitute a DMRS frequency offset compensation sequence set {v (1) ,v (2) ,v (3)}.

[0108] If the physical layer channel is configured with 3 DMRS symbols, the frequency offset estimation value is used Perform frequency offset compensation on the three DMRS symbols to obtain the compensation sequence u of the first DMRS symbol. (1,1) , the compensation sequence u of the second DMRS symbol (1,2) , the compensation sequence u of the third DMRS symbol (1,3) ; Sequence u (1,1) 、u (1,2) 、u (1,3) Splice into a sequence v (1) =(u (1,1) ,u (1,2) ,u (1,3) ). Similarly, using the frequency offset estimate The available sequence v (2) ; Using the frequency offset estimate The available sequence v (3) ; Sequence v (1) 、v (2) 、v (3) Constitute a DMRS frequency offset compensation sequence set {v (1) ,v (2) ,v (3)}.

[0109] If the physical layer channel is configured with 4 DMRS symbols, the frequency offset estimation value is used Frequency offset compensation is performed on the four DMRS symbols to obtain the compensation sequence u of the first DMRS symbol. (1,1) , the compensation sequence u of the second DMRS symbol (1,2) , the compensation sequence u of the third DMRS symbol (1,3) , the compensation sequence u of the fourth DMRS symbol (1,4) ; Sequence u (1,1) 、u (1,2) 、u (1,3) 、u (1,4) Splice into a sequence v (1) =(u (1,1) ,u(1,2) ,u (1,3) ,u (1,4) ). Similarly, using the frequency offset estimate The available sequence v (2) ; Using the frequency offset estimate The available sequence v (3) ; Sequence v (1) 、v (2) 、v (3) Constitute a DMRS frequency offset compensation sequence set {v (1) ,v (2) ,v (3)}.

[0110] When solving the final frequency offset estimation value by using the DMRS frequency offset compensation sequence set, let the second frequency offset estimation value set

[0111] Let the DMRS frequency offset compensation sequence set {v (1) ,v (2) ,v (3)}, and let the length of each sequence in the set be 8, and each sequence is represented as the following row vector

[0112] Let the local sequence of DMRS symbols w = (w1, w2, ..., w8), and the conjugate of each element of w is recorded as Let the number of segments Q = 2;

[0113] Calculate the sequence v (1) Segment-wise correlation with w as well as Calculate the sum of two segment correlation values

[0114] Calculate the sequence v (2) Segment-wise correlation with w as well as Calculate the sum of two segment correlation values

[0115] Calculate the sequence v (3) Segment-wise correlation with w as well as Calculate the sum of two segment correlation values

[0116] Assume that the calculated correlation value set {R(1) ,R (2) ,R (3)}={0.81,0.98,0.78}, the element index corresponding to the maximum value in this set is i * =2, then the second frequency offset estimation value set The second element 0.78kHz in is output as the frequency offset estimation result.

[0117] The frequency offset estimation device based on the 5G demodulation reference signal provided by the present invention is described below. The frequency offset estimation device based on the 5G demodulation reference signal described below and the frequency offset estimation method based on the 5G demodulation reference signal described above can correspond to each other.

[0118] like Figure 6 As shown, the device includes a frequency offset estimation module 601, a frequency offset update module 602, a frequency offset compensation module 603 and a correlation operation module 604, wherein:

[0119] The frequency offset estimation module 601 is used to determine a first frequency offset estimation value set of the physical layer channel according to a frequency domain received sequence and a local sequence of a DMRS symbol configured by the physical layer channel;

[0120] The frequency offset updating module 602 is configured to remove frequency offset estimation values ​​whose absolute values ​​are greater than a preset threshold from the first frequency offset estimation value set, to obtain a second frequency offset estimation value set;

[0121] The frequency offset compensation module 603 is used to use each frequency offset estimation value in the second frequency offset estimation value set to perform frequency offset compensation on the DMRS symbol to obtain a frequency offset compensation sequence of each frequency offset estimation value on the DMRS symbol;

[0122] The correlation operation module 604 is used to perform a correlation operation on each frequency offset estimation value in the second frequency offset estimation value set with the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol to obtain a correlation value, and use the frequency offset estimation value corresponding to the maximum correlation value as the frequency offset estimation result of the physical layer channel.

[0123] Figure 7 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 7As shown, the electronic device may include: a processor (processor) 710, a communication interface (Communications Interface) 720, a memory (memory) 730 and a communication bus 740, wherein the processor 710, the communication interface 720, and the memory 730 communicate with each other through the communication bus 740. The processor 710 can call the logic instructions in the memory 730 to execute a frequency offset estimation method based on a 5G demodulation reference signal, the method comprising: determining a first frequency offset estimation value set according to the frequency domain receiving sequence and the local sequence of the DMRS symbol configured by the physical layer channel; removing the frequency offset estimation values ​​whose absolute values ​​are greater than a preset threshold in the first frequency offset estimation value set to obtain a second frequency offset estimation value set; using each frequency offset estimation value in the second frequency offset estimation value set to perform frequency offset compensation on the DMRS symbol to obtain a frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol; correlating the frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol in the second frequency offset estimation value set with the local sequence of the DMRS symbol to obtain a correlation value, and taking the frequency offset estimation value corresponding to the maximum correlation value as the frequency offset estimation result.

[0124] In addition, the logic instructions in the above-mentioned memory 730 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0125] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the frequency offset estimation method based on the 5G demodulation reference signal provided by the above-mentioned methods, the method including: determining a first frequency offset estimation value set according to the frequency domain receiving sequence and local sequence of the DMRS symbol configured by the physical layer channel; eliminating the frequency offset estimation values ​​whose absolute values ​​are greater than a preset threshold in the first frequency offset estimation value set to obtain a second frequency offset estimation value set; using each frequency offset estimation value in the second frequency offset estimation value set to perform frequency offset compensation on the DMRS symbol to obtain a frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol; correlating the frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol in the second frequency offset estimation value set with the local sequence of the DMRS symbol to obtain a correlation value, and taking the frequency offset estimation value corresponding to the maximum correlation value as the frequency offset estimation result.

[0126] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the frequency offset estimation method based on the 5G demodulation reference signal provided by the above-mentioned methods, the method comprising: determining a first frequency offset estimation value set according to the frequency domain receiving sequence and local sequence of the DMRS symbol configured by the physical layer channel; eliminating the frequency offset estimation values ​​whose absolute values ​​in the first frequency offset estimation value set are greater than a preset threshold to obtain a second frequency offset estimation value set; using each frequency offset estimation value in the second frequency offset estimation value set to perform frequency offset compensation on the DMRS symbol to obtain a frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol; correlating the frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol in the second frequency offset estimation value set with the local sequence of the DMRS symbol to obtain a correlation value, and taking the frequency offset estimation value corresponding to the maximum correlation value as the frequency offset estimation result.

[0127] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0128] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A frequency offset estimation method based on a 5G demodulation reference signal, characterized in that: include: Determine a first frequency offset estimation value set of the physical layer channel according to a frequency domain received sequence and a local sequence of a DMRS symbol configured by the physical layer channel; Eliminate frequency offset estimation values ​​whose absolute values ​​are greater than a preset threshold in the first frequency offset estimation value set to obtain a second frequency offset estimation value set; Perform frequency offset compensation on the DMRS symbol using each frequency offset estimation value in the second frequency offset estimation value set to obtain a frequency offset compensation sequence of the DMRS symbol using each frequency offset estimation value; Correlation operation is performed on each frequency offset estimation value in the second frequency offset estimation value set with the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol to obtain a correlation value, and the frequency offset estimation value corresponding to the maximum correlation value is used as the frequency offset estimation result of the physical layer channel.

2. The frequency offset estimation method based on the 5G demodulation reference signal according to claim 1, characterized in that: Determining a first frequency offset estimation value set of the physical layer channel according to a frequency domain received sequence and a local sequence of a DMRS symbol configured by the physical layer channel, including: Determine the frequency domain channel of each DMRS symbol according to the frequency domain reception sequence and the local sequence of the DMRS symbol configured by the physical layer channel; Determining a phase difference between the DMRS symbols according to the frequency domain channels of the DMRS symbols; The first frequency offset estimation value set is determined according to the phase difference.

3. The frequency offset estimation method based on the 5G demodulation reference signal according to claim 2, characterized in that: The DMRS symbol includes a first DMRS symbol and a second DMRS symbol, wherein the first DMRS symbol and the second DMRS symbol correspond to the first and second DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index; The first frequency offset estimation value set is determined according to the phase difference by the following formula: in, is a frequency offset estimation value in the first frequency offset estimation value set, wherein the first frequency offset estimation value set is θ is the phase difference between the first DMRS symbol and the second DMRS symbol, M is 0 or a positive integer, C1 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the second DMRS symbol, and T is the sampling period of the first DMRS symbol and the second DMRS symbol.

4. The frequency offset estimation method based on the 5G demodulation reference signal according to claim 2, characterized in that: The DMRS symbols include a first DMRS symbol, a second DMRS symbol and a third DMRS symbol; The first frequency offset estimation value set is determined according to the phase difference by the following formula: wherein the function mod(x,2π) represents the modulo operation of x on 2π, M is 0 or a positive integer, θ1 is the phase difference between the first DMRS symbol and the second DMRS symbol, θ2 is the phase difference between the first DMRS symbol and the third DMRS symbol, C1 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the second DMRS symbol, and C2 is the number of sampling points between the first sampling point of the first DMRS symbol and the first sampling point of the third DMRS symbol; If s(N1)≤π, then r(N1)=s(N1); if s(N1)>π, then r(N1)=s(N1)-2π; in, is a frequency offset estimation value in the first frequency offset estimation value set, wherein the first frequency offset estimation value set is T is a sampling period of the first DMRS symbol, the second DMRS symbol and the third DMRS symbol.

5. The frequency offset estimation method based on the 5G demodulation reference signal according to claim 4, characterized in that: In the case where the physical layer channel is configured with 3 DMRS symbols, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the first, second and third DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index; In the case where the physical layer channel is configured with 4 DMRS symbols, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the 1st, 2nd and 3rd DMRS symbols, or the 1st, 2nd and 4th DMRS symbols, or the 2nd, 3rd and 4th DMRS symbols of the OFDM symbols in the physical layer channel sorted in ascending order of index.

6. The frequency offset estimation method based on the 5G demodulation reference signal according to any one of claims 1 to 5, characterized in that: The method of performing a correlation operation on the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol using each frequency offset estimation value in the second frequency offset estimation value set to obtain a correlation value includes: Dividing the frequency offset compensation sequence corresponding to each frequency offset estimation value in the second frequency offset estimation value set and the local sequence of the DMRS symbol into the same number of segments; Performing a correlation operation on each segment of the frequency offset compensation sequence corresponding to each frequency offset estimation value in the second frequency offset estimation value set and a corresponding segment of the local sequence of the DMRS symbol to obtain a correlation value of each segment; The correlation values ​​of each segment are added together to obtain the correlation value between the frequency offset compensation sequence corresponding to each frequency offset estimation value in the second frequency offset estimation value set and the local sequence of the DMRS symbol.

7. The frequency offset estimation method based on the 5G demodulation reference signal according to any one of claims 1 to 5, characterized in that: The physical layer channels include a physical uplink shared channel, a physical uplink control channel, a physical downlink shared channel and a physical downlink control channel.

8. A frequency offset estimation device based on a 5G demodulation reference signal, characterized in that: include: A frequency offset estimation module, configured to determine a first frequency offset estimation value set of the physical layer channel according to a frequency domain received sequence and a local sequence of a DMRS symbol configured by the physical layer channel; A frequency offset updating module, configured to remove frequency offset estimation values ​​whose absolute values ​​are greater than a preset threshold in the first frequency offset estimation value set, to obtain a second frequency offset estimation value set; A frequency offset compensation module, configured to perform frequency offset compensation on the DMRS symbol using each frequency offset estimation value in the second frequency offset estimation value set, to obtain a frequency offset compensation sequence of each frequency offset estimation value for the DMRS symbol; The correlation operation module is used to perform a correlation operation on each frequency offset estimation value in the second frequency offset estimation value set with respect to the frequency offset compensation sequence of the DMRS symbol and the local sequence of the DMRS symbol to obtain a correlation value, and use the frequency offset estimation value corresponding to the maximum correlation value as the frequency offset estimation result of the physical layer channel.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the frequency offset estimation method based on the 5G demodulation reference signal is implemented as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the frequency offset estimation method based on the 5G demodulation reference signal is implemented as described in any one of claims 1 to 7.

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