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

Abstract

The application provides a frequency offset estimation method and device based on a 5G demodulation reference signal, which comprises the following steps: determining a first frequency offset estimation value set according to a frequency domain receiving sequence of a DMRS symbol configured by a physical layer channel and a local sequence; removing the frequency offset estimation values with absolute values greater than a preset threshold from 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 the second frequency offset estimation value set to obtain a frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value; performing correlation operation on the frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value and 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 a frequency offset estimation result. The application effectively improves the frequency offset estimation range, enables the system to support greater Doppler frequency offset tracking and compensation, and further supports greater relative moving speed of the transmitting and receiving ends.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and in particular to a method and device for frequency offset estimation 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 effect causes the system's Doppler frequency deviation to rapidly decrease from positive to negative values ​​as high-speed terminals approach and move away from base stations. This causes a large rate of change in the frequency deviation, necessitating real-time tracking and compensation of the frequency deviation. Furthermore, the relative high speed of the terminal and base station results in a large Doppler frequency deviation range. 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] 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 signal configuration density 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 application provides a frequency offset estimation method and device based on a 5G demodulation reference signal, to solve the defect that the frequency offset estimation range based on the phase difference of a DMRS signal is limited in the prior art, and it is difficult to be applied to the large Doppler frequency offset value generated in a high-speed mobile scenario, so as to realize improving the estimation frequency offset range based on the DMRS method, so that the system supports a larger Doppler frequency offset estimation range, and the transceiver end of the system supports a higher relative moving speed.

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

[0007] According to the frequency domain receiving 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;

[0008] The frequency offset estimation value with an absolute value greater than a preset threshold in the first frequency offset estimation value set is eliminated, and a second frequency offset estimation value set is obtained;

[0009] The DMRS symbol is frequency offset compensated by using each frequency offset estimation value in the second frequency offset estimation value set, and a frequency offset compensation sequence of the DMRS symbol by the each frequency offset estimation value is obtained;

[0010] The frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value in the second frequency offset estimation value set and the local sequence of the DMRS symbol are correlated to obtain a correlation value, and the frequency offset estimation value corresponding to the maximum correlation value is taken as the frequency offset estimation result of the physical layer channel.

[0011] According to the frequency offset estimation method based on the 5G demodulation reference signal provided by the application, according to the frequency domain receiving 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, comprising:

[0012] According to the frequency domain receiving sequence and the local sequence of the DMRS symbol configured by the physical layer channel, the frequency domain channel of each DMRS symbol is determined;

[0013] According to the frequency domain channel of each DMRS symbol, the phase difference between the DMRS symbols is determined;

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

[0015] According to the frequency offset estimation method based on the 5G demodulation reference signal provided by the application, the DMRS symbol comprises a first DMRS symbol and a second DMRS symbol, and the first DMRS symbol and the second DMRS symbol correspond to the 1st and 2nd DMRS symbols in the physical layer channel in the index ascending order.

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

[0017]

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

[0019] According to the present application, a frequency offset estimation method based on a 5G demodulation reference signal is provided, wherein the DMRS symbol comprises 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 a modulo operation of x on 2π, M is 0 or a positive integer, θ1 is a phase difference between the first DMRS symbol and the second DMRS symbol, θ2 is a phase difference between the first DMRS symbol and the third DMRS symbol, C1 is a number of sampling points between a first sampling point of the first DMRS symbol and a first sampling point of the second DMRS symbol, and C2 is a number of sampling points between a first sampling point of the first DMRS symbol and a 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] wherein, is a frequency offset estimation value in the first frequency offset estimation value set, 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 the frequency offset estimation method based on the 5G demodulation reference signal provided by the application, in the case that the physical layer channel is configured with three DMRS symbols, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the first, the second and the third DMRS symbols in the physical layer channel in ascending order of index of OFDM symbols.

[0027] In the case that the physical layer channel is configured with four DMRS symbols, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the first, the second and the third DMRS symbols, or the first, the second and the fourth DMRS symbols, or the second, the third and the fourth DMRS symbols in ascending order of index of OFDM symbols in the physical layer channel.

[0028] According to the frequency offset estimation method based on the 5G demodulation reference signal provided by the application, the correlation value is obtained by correlating the frequency offset compensation sequence corresponding to each frequency offset estimation value in the second frequency offset estimation value set with the local sequence of the DMRS symbol, including:

[0029] 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 are divided into the same number of segments.

[0030] Each segment of the frequency offset compensation sequence corresponding to each frequency offset estimation value in the second frequency offset estimation value set is correlated with the corresponding segment of the local sequence of the DMRS symbol to obtain the correlation value of each segment.

[0031] The correlation values of each segment are added to obtain the correlation value of 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 the frequency offset estimation method based on the 5G demodulation reference signal provided by the application, 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 application also provides a frequency offset estimation device based on the 5G demodulation reference signal, comprising:

[0034] The frequency offset estimation module is configured to determine a first frequency offset estimation value set of the physical layer channel according to the frequency domain receiving sequence and the local sequence of the DMRS symbol configured by the physical layer channel.

[0035] The frequency offset updating module is configured to eliminate the frequency offset estimation value with an absolute value 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] A 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 runnable on the processor. When the processor executes the program, it implements any of the above-described frequency offset estimation methods based on the 5G demodulation reference signal.

[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 any of the above-described frequency offset estimation methods based on a 5G demodulation reference signal.

[0040] The present invention also provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-mentioned frequency offset estimation methods based on the 5G demodulation reference signal.

[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 movement speed between the transmitter and receiver. In addition, unlike SSB, which is only configured in the 5G downlink channel, DMRS is configured in both the 5G uplink and downlink channels. Therefore, 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 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 rail 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0043] Figure 1is a flowchart of the method for estimating frequency offset based on 5G demodulation reference signal provided by the application;

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

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

[0046] Figure 4 is a schematic diagram of configuring four DMRS symbols of a physical layer channel in the method for estimating frequency offset based on 5G demodulation reference signal provided by the application;

[0047] Figure 5 is a flowchart of obtaining a DMRS frequency offset compensation sequence set when four DMRS symbols of a physical layer channel are configured in the method for estimating frequency offset based on 5G demodulation reference signal provided by the application;

[0048] Figure 6 is a structural schematic diagram of the device for estimating frequency offset based on 5G demodulation reference signal provided by the application;

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

[0050] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0051] 5G mobile communication system physical layer mainly adopts OFDM-based waveform modulation technology, in order to realize the uplink and downlink data transmission, 5G physical layer channel is divided according to the function of uplink and downlink transmission respectively defined 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) and so on. By allocating different time-frequency domain resources to the physical layer channel, the corresponding information is transmitted. 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, which are used to transmit 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 the demodulation of data symbols.

[0052] OFDM modulation waveform is a multicarrier modulation technology, and its demodulation performance is sensitive to frequency offset. Excessive frequency offset will cause signal interference between multicarriers, and reduce the receiving performance. 5G physical layer introduces synchronization signal block (Synchronization Signal Block, SSB) in downlink broadcast channel. The primary synchronization signal (Primary Synchronization Signal, PSS) and secondary synchronization signal (Secondary Synchronization Signal, SSS) contained in the SSB can realize the time-frequency synchronization of downlink transmission.

[0053] The following will be described in detail Figure 1 The present application discloses a frequency offset estimation method based on 5G demodulation reference signal, comprising:

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

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

[0056] Step 102, the frequency offset estimation value with absolute value greater than the preset threshold in the first frequency offset estimation value set is eliminated, and the second frequency offset estimation value set is obtained;

[0057] using a preset threshold f max The frequency offset estimation values in the first frequency offset estimation value set are sequentially determined, and the frequency offset estimation values with absolute values greater than a preset threshold f are removed to obtain a second frequency offset estimation value set. max

[0058] In step 103, each frequency offset estimation value in the second frequency offset estimation value set is used to compensate the DMRS symbol for frequency offset to obtain a frequency offset compensation sequence of the DMRS symbol for the frequency offset estimation value.

[0059] In step 104, the frequency offset compensation sequence of the DMRS symbol for the frequency offset estimation value is correlated with a local sequence of the DMRS symbol to obtain a correlation value, and the frequency offset estimation value corresponding to the maximum correlation value is taken as a frequency offset estimation result of the physical layer channel.

[0060] The embodiment effectively improves the frequency offset estimation range by using the autocorrelation of the DMRS symbol configured by the 5G physical layer channel and the 2π periodicity in phase difference calculation, so that the system supports larger Doppler frequency offset tracking and compensation, and further supports larger relative moving speed of the transceiver.

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

[0062] The frequency domain channel of each DMRS symbol is determined according to the frequency domain receiving sequence and the local sequence of the DMRS symbol configured by the physical layer channel.

[0063] The phase difference between the DMRS symbols is determined according to the frequency domain channel of each DMRS symbol.

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

[0065] The number of DMRS symbols configured by 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 the embodiment, the number of DMRS symbols is not less than 2.

[0066] On the basis of the above-mentioned embodiment, in the embodiment, the DMRS symbol comprises 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 in the physical layer channel in ascending order of index of the OFDM symbol.

[0067] As Figure 2 ​As shown, if the physical layer channel configures 2 DMRS symbols, i.e. a first DMRS symbol and a second DMRS symbol, the frequency domain channels of the first DMRS symbol and the second DMRS symbol are estimated according to the frequency domain received sequence and the local sequence of the DMRS symbol. The phase difference θ between the first DMRS symbol and the second DMRS symbol is calculated according to the frequency domain channels of the first DMRS symbol and the second DMRS symbol. The first frequency offset estimation value set is calculated according to the phase difference θ by the following formula:

[0068]

[0069] wherein, is a frequency offset estimation value in the first frequency offset estimation value set, 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 configures 3 or 4 DMRS symbols, 3 DMRS symbols are used for frequency offset estimation, i.e. the DMRS symbols in the embodiment include a first DMRS symbol, a second DMRS symbol and a third DMRS symbol.

[0071] The frequency domain channels of the first DMRS symbol, the second DMRS symbol and the third DMRS symbol are estimated according to the frequency domain received sequence and the local sequence of the DMRS symbol. 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. The first frequency offset estimation value set is calculated according to the phase differences θ1 and θ2 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, r(N1)=s(N1); if s(N1)>π, r(N1)=s(N1)-2π;

[0075]

[0076] wherein, is a frequency offset estimation value in the first frequency offset estimation value set, 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 with an absolute value greater than a preset threshold f max in the first frequency offset estimation value set is eliminated, and the remaining frequency offset estimation values constitute a 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 to compensate the frequency offset of the jth DMRS symbol in the physical layer channel, to obtain a sequence u (i,j) . Wherein j=1, 2, …, P, P represents the number of DMRS symbols configured by the physical layer channel.

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

[0080] On the basis of the above embodiment, as shown in Figure 3 , in the case of 3 DMRS symbols configured by the physical layer channel, the first DMRS symbol, the second DMRS symbol and the third DMRS symbol correspond to the 1st, 2nd and 3rd DMRS symbols in the physical layer channel in ascending order of index of OFDM symbol;

[0081] As shown in Figure 4As shown in the physical layer channel configuration 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 in ascending order of index, as shown in Figure 4 (b); or the first, second and fourth DMRS symbols, as shown in Figure 4 (a); or the second, third and fourth DMRS symbols, as shown in Figure 4 (c).

[0082] On the basis of the above-mentioned embodiments, in the present embodiment, the correlation value of the frequency offset compensation sequence of each frequency offset estimation value and the local sequence of the DMRS symbol is obtained by correlating the frequency offset compensation sequence of each frequency offset estimation value and the local sequence of the DMRS symbol, including:

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

[0084] Each segment of the frequency offset compensation sequence corresponding to each frequency offset estimation value is correlated with the corresponding segment of the local sequence of the DMRS symbol to obtain the correlation value of each segment;

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

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

[0087] Each sequence v (1) ,v (2) ,…,v (L) in the frequency offset compensation sequence set {v (i) of the DMRS symbol is divided into Q segments with the DMRS local sequence w, respectively, to obtain and w=(w1,w2,…,w Q ), where, and w q are the qth segment of v (i) and w, i=1,2,..,L, q=1,2,…,Q.

[0088] The sequence With w q Perform autocorrelation operation to obtain the autocorrelation value And calculate 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 value 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 includes:

[0092] If the physical layer channel is configured with two 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 the 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 configures 4 DMRS symbols, let the channel estimation result of the 1st DMRS symbol be the channel estimation result of the 2nd DMRS symbol be the channel estimation result of the 3rd DMRS symbol be the channel estimation result of the 4th DMRS symbol be The calculation method of phase difference θ1 and θ2 can be one of the following three methods.

[0095] Method one: according to the channel estimation results H (1) and H (2) , the phase difference is calculated according to the channel estimation results H (1) and H (4) , the phase difference

[0096] Method two: according to the channel estimation results H (1) and H (23) , the phase difference is calculated according to the channel estimation results H (1) and H (3) , the phase difference

[0097] Method three: according to the channel estimation results H (2) and H (3) , the phase difference is calculated according to the channel estimation results H (2) and H (4) , the phase difference

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

[0099] The initial frequency offset estimation value is calculated as N1=0,±1,±2, and the first frequency offset estimation value set is

[0100] If the physical layer channel configures 3 or 4 DMRS symbols, let the phase difference M=2, C1=21920, C2=39456, and a sampling period is second;

[0101] Calculating s(-2)=3.9270, s(-1)=5.1836, s(0)=0.1571, s(1)=1.4137, and s(2)=2.6704.

[0102] According to s(N1), r(N1) is calculated, if s(N1)≤π, r(N1)=s(N1); if s(N1)>π, r(N1)=s(N1)-2π, then r(-2)=0.7854, r(-1)=2.0420, r(0)=0.1571, r(1)=1.4137, and r(2)=2.6704.

[0103] According to the θ1, C1, C2, r(N1), and N1=0,±1,±2, an initial frequency offset estimation value The first frequency offset estimation value set is:

[0104]

[0105] When the second frequency offset estimation value set is solved by using a preset threshold, 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}, and the elements in the first frequency offset estimation value set whose absolute values are greater than f max are removed, and the remaining elements constitute the second frequency offset estimation value set The second frequency offset estimation value set is:

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

[0107] If the physical layer channel configures two DMRS symbols, the frequency offset estimation value is used to compensate the two DMRS symbols, and a compensation sequence u (1,1) of the first DMRS symbol and a compensation sequence u (1,2) of the second DMRS symbol are obtained; the sequences u (1,1) and u (1,2) are spliced 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 Perform frequency offset compensation 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, the frequency offset estimation value The sequence v (2) is obtained using the frequency offset estimation value The sequence v (3) is obtained using the frequency offset estimation value (1) , v (2) , v (3) constitute a DMRS frequency offset compensation sequence set {v (1) , v (2) , v (3)}.

[0110] In the use of the DMRS frequency offset compensation sequence set, the final frequency offset estimation value is solved, and the second frequency offset estimation value set

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

[0112] Let the local sequence of the DMRS symbol w = (w1, w2, …, w8), and the conjugate of each element of w is Let the segment number Q = 2;

[0113] Calculate the segment correlation value of the sequence v (1) and w and Calculate the sum of the two segment correlation values

[0114] Calculate the segment correlation value of the sequence v (2) and w and Calculate the sum of the two segment correlation values

[0115] Calculate the segment correlation value of the sequence v (3) and w and Calculate the sum of the two segment correlation values

[0116] Assuming that the correlation value set {R(1) ,R (2) ,R (3)}={0.81,0.98,0.78}, the maximum value in the set corresponds to the element index i * =2, the second frequency offset estimation value set The second element 0.78 kHz in the second frequency offset estimation value set

[0117] The following describes the frequency offset estimation device based on 5G demodulation reference signal provided by the application. The frequency offset estimation device based on 5G demodulation reference signal described below can be mutually corresponding to the frequency offset estimation method based on 5G demodulation reference signal described above.

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

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

[0120] The frequency offset updating module 602 is configured to eliminate the frequency offset estimation value with an absolute value greater than a preset threshold in the first frequency offset estimation value set to obtain a second frequency offset estimation value set.

[0121] The frequency offset compensation module 603 is configured to compensate the DMRS symbol with each frequency offset estimation value in the second frequency offset estimation value set to obtain a frequency offset compensation sequence of the DMRS symbol.

[0122] The correlation operation module 604 is configured to perform correlation operation on the frequency offset compensation sequence of the DMRS symbol with each frequency offset estimation value in the second frequency offset estimation value set and the local sequence of the DMRS symbol to obtain a correlation value, and take 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 an electronic device is shown in the entity structure diagram, as Figure 7As shown, the electronic device can include a processor 710, a communications interface 720, a memory 730, and a communications bus 740, wherein the processor 710, the communications interface 720, and the memory 730 complete mutual communication through the communications bus 740. The processor 710 can invoke a logic instruction in the memory 730 to execute a 5G demodulation reference signal-based frequency offset estimation method, which includes: determining a first frequency offset estimation value set according to a frequency domain receiving sequence of a DMRS symbol configured by a physical layer channel and a local sequence; eliminating a frequency offset estimation value with an absolute value greater than a preset threshold 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 the second frequency offset estimation value set to obtain a frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value; and performing correlation operation on the frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value in the second frequency offset estimation value set and the local sequence of the DMRS symbol to obtain a correlation value, taking the frequency offset estimation value corresponding to the maximum correlation value as a frequency offset estimation result.

[0124] In addition, the logic instruction in the memory 730 described above can be implemented in the form of a software functional unit and sold or used as an independent product, which can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various program code storage media.

[0125] In another aspect, the present application also provides a computer program product, which comprises a computer program, the computer program being stored in a non-transitory computer readable storage medium, and the computer program being executable by a processor to enable a computer to perform the method for estimating frequency offset based on 5G demodulation reference signal, the method comprising: determining a first set of frequency offset estimation values according to a frequency domain received sequence of a DMRS symbol configured by a physical layer channel and a local sequence; eliminating frequency offset estimation values in the first set of frequency offset estimation values whose absolute values are greater than a preset threshold to obtain a second set of frequency offset estimation values; performing frequency offset compensation on the DMRS symbol by using each frequency offset estimation value in the second set of frequency offset estimation values to obtain a frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value; and performing correlation operation on the frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value in the second set of frequency offset estimation values and 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 a frequency offset estimation result.

[0126] In another aspect, the present application also provides a non-transitory computer readable storage medium, which stores a computer program, and the computer program is executable by a processor to implement the method for estimating frequency offset based on 5G demodulation reference signal, the method comprising: determining a first set of frequency offset estimation values according to a frequency domain received sequence of a DMRS symbol configured by a physical layer channel and a local sequence; eliminating frequency offset estimation values in the first set of frequency offset estimation values whose absolute values are greater than a preset threshold to obtain a second set of frequency offset estimation values; performing frequency offset compensation on the DMRS symbol by using each frequency offset estimation value in the second set of frequency offset estimation values to obtain a frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value; and performing correlation operation on the frequency offset compensation sequence of the DMRS symbol by each frequency offset estimation value in the second set of frequency offset estimation values and 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 a frequency offset estimation result.

[0127] The device embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., they can be located in one place, or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the present embodiment scheme according to actual needs. Those skilled in the art can understand and implement it without creative labor.

[0128] Those skilled in the art can clearly understand the technical solutions of the various embodiments from the above description of the embodiments, and the various embodiments can be implemented by means of software with the necessary general hardware platforms, and of course, can also be implemented by hardware. Based on such understanding, the above technical solutions, essentially or in other words, the part of the prior art that makes a contribution, can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, and the like, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments 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 application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

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 DMRS symbols configured for the physical layer channel; Eliminate 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; 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 the DMRS symbol using each frequency offset estimation value; performing 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 taking the frequency offset estimation value corresponding to the maximum correlation value as the frequency offset estimation result of the physical layer channel; 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 for the physical layer channel, including: Determine the frequency domain channel of each DMRS symbol according to the frequency domain reception sequence and 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; determining the first frequency offset estimation value set according to the phase difference; 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, comprising: 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 a 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.

2. The frequency offset estimation method based on the 5G demodulation reference signal according to claim 1, characterized in that The DMRS symbol includes a first DMRS symbol and a second DMRS symbol, where 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 using 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 , is the phase difference between the first DMRS symbol and the second DMRS symbol, M is 0 or a positive integer, 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, is the sampling period of the first DMRS symbol and the second DMRS symbol.

3. The frequency offset estimation method based on the 5G demodulation reference signal according to claim 1, 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 using the following formula: Among them, the function express For the modulo operation of 2π, M is 0 or a positive integer. is the phase difference between the first DMRS symbol and the second DMRS symbol, is the phase difference between the first DMRS symbol and the third DMRS symbol, 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, 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; like ,but ;like ,but ; 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 the sampling period of the first DMRS symbol, the second DMRS symbol and the third DMRS symbol.

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

5. The frequency offset estimation method based on the 5G demodulation reference signal according to any one of claims 1 to 4, 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.

6. 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 DMRS symbols configured for 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 from 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; a correlation operation module, configured 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; 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 for the physical layer channel, including: Determine the frequency domain channel of each DMRS symbol according to the frequency domain reception sequence and 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; determining the first frequency offset estimation value set according to the phase difference; 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, comprising: 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 a 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. 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, it implements the frequency offset estimation method based on the 5G demodulation reference signal as described in any one of claims 1 to 5.

8. 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 5.

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