Phase noise level estimation method

Abstract

The invention relates to a phase noise level estimation method, which belongs to the field of wireless communication, and comprises the following steps: S1, a frequency hopping communication transmitter performs digital-to-analog conversion and frequency hopping modulation on a desired signal and then transmits the desired signal; s2, the frequency hopping communication receiver sequentially performs frequency hopping synchronization and analog-to-digital conversion on the received signal to obtain a digital baseband signal; and S3, the frequency hopping communication receiver performs phase noise level estimation by using the synchronization hop information. According to the method, the phase noise level of the frequency oscillation device in the frequency hopping communication system is accurately estimated at the cost of less resource consumption, and the method has important guiding significance for hardware error suppression in actual engineering.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and in particular to a phase noise level estimation method. Background Art

[0002] Frequency hopping communication systems have been widely used in military and civilian communications by changing the carrier frequency to combat interference; however, the hopping carrier will cause significant fragrance noise at the transmitting and receiving frequency oscillators, resulting in signal distortion and reduced communication reception quality.

[0003] Accurately estimating the variance level of phase noise is a prerequisite for supporting the Kalman filter algorithm to suppress phase noise; therefore, how to use the synchronization hopping information of the frequency hopping communication system to accurately estimate the phase noise level of the frequency oscillator device in the frequency hopping communication system at the cost of less resource consumption is a problem that needs to be considered at present. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a phase noise level estimation method to solve the deficiencies of the prior art.

[0005] The objective of the present invention is achieved by the following technical solution: a phase noise level estimation method, the method comprising:

[0006] S1, the frequency hopping communication transmitter performs digital-to-analog conversion and frequency hopping modulation on the desired signal and then transmits it;

[0007] S2, the frequency hopping communication receiver performs frequency hopping synchronization and analog-to-digital conversion on the received signal in sequence to obtain a digital baseband signal;

[0008] S3. The frequency hopping communication receiver uses the synchronization hopping information to estimate the phase noise level.

[0009] In S1, at the frequency hopping communication transmitter, the signal vector transmitted at the pth hop is expressed as:

[0010]

[0011] in, represents the Hadamard product, y[m] represents the symbol sent at the mth time, (p-1)N+1≤m≤pN, N represents the number of symbols per hop, (·) T represents the transpose operation, X p represents the expected signal vector in the p-th hop transmitted signal, f i represents the center frequency of the p-th hop signal, T p represents the sampling time vector of the p-th hop signal, represents the transmit phase noise vector in the p-th hop signal, θ Tx[m] is the transmit phase noise at the mth moment;

[0012] Phase noiseθ Tx [m] is modeled as a Wiener process of irregular motion, and satisfies the formula:

[0013]

[0014] Among them, Δ Tx [i] is a set of independent and identically distributed Gaussian random variables.

[0015] In S2, at the frequency hopping communication receiver, after frequency hopping synchronization is performed on the received signal, the obtained p-th hop baseband symbiotic signal is expressed as:

[0016]

[0017] Among them, h p represents the channel attenuation between the transmitter and receiver of a frequency hopping communication. represents the N-dimensional received noise column vector, where the dimension N is consistent with the number of symbols per hop signal N, and w p express The equivalent baseband form of represents the phase noise vector in the pth frequency hopping carrier at the receiver.

[0018] The steps of S3 include the following:

[0019] S301, set the period of the frequency hopping pattern to N p The first hop is a synchronization hop for frequency hopping synchronization. The phase noise is estimated by using the synchronization hop. The estimated phase noise vector is The average estimate of the phase noise during a synchronization hop is Among them, r1 represents the baseband symbiotic signal, x1 * represents the conjugate of the desired signal vector in the transmitted signal, ∠(·) represents the phase of (·), h1 represents the channel attenuation between the frequency hopping communication transmitter and the receiver, and I N represents an N-dimensional unit vector, represents the phase noise estimation value at the mth moment, ∈1 is an N-dimensional column vector, representing the error vector of the phase noise estimation;

[0020] S302, because the transmission and reception phase noises are independent of each other, the increments of the transmission phase noise and the reception phase noise obey Gaussian distribution, so the increment of the joint transmission and reception phase noise obeys Gaussian distribution, and only the joint 3dB coherence bandwidth of the transmission and reception frequency oscillators is estimated at the receiving end. Record it as That is to say, the level estimation of phase noise is completed. represents the single sideband 3dB coherence bandwidth of the frequency oscillator in the receiver, It represents the single sideband 3dB coherence bandwidth of the transmitting frequency oscillator.

[0021] The present invention has the following advantages: a phase noise level estimation method accurately estimates the phase noise level of a frequency oscillator device in a frequency hopping communication system at the cost of less resource consumption, and has important guiding significance for hardware error suppression in practical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the process of the present invention;

[0023] Figure 2 Performance simulation plot for phase noise level estimation. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the drawings is not intended to limit the scope of protection of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. The present invention is further described below in conjunction with the drawings.

[0025] like Figure 1 As shown, the present invention uses a method for estimating the phase noise level by using synchronization hop information. After the received signal is converted into a digital baseband signal, the phase noise vector is estimated by using synchronization hop, and then a 3dB coherent bandwidth estimation operation is performed, thereby achieving effective estimation of the phase noise level; specifically, the following contents are included.

[0026] S1. The frequency hopping communication transmitter performs digital-to-analog conversion and frequency hopping modulation on the desired signal before transmitting;

[0027] S2. The frequency hopping communication receiver first performs frequency hopping capture on the received signal in sequence, and reduces the time error between the local frequency hopping sequence at the frequency hopping communication receiver and the frequency hopping sequence of the frequency hopping transmission to within the capture accuracy. Then, the frequency hopping tracking operation is performed to complete the frequency hopping synchronization, and then the digital baseband signal is obtained through analog-to-digital conversion;

[0028] S3. The frequency hopping communication receiver uses the synchronization hopping information to estimate the phase noise level.

[0029] Furthermore, in step S1, considering the situation where phase noise exists at the transmission frequency oscillator, the signal vector of the p-th hop transmission at the frequency hopping communication transmitter can be expressed as:

[0030]

[0031] Where p is a positive integer. represents the Hadamard product, y[m] represents the symbol sent at the mth time, (p-1)N+1≤m≤pN, N represents the number of symbols per hop, (·) T represents the transpose operation; x p =[x[(p-1)N+1],...,x[pN-1],x[pN]] T represents the expected signal vector in the p-th hop transmitted signal, x[m] represents the expected signal transmitted at the m-th moment; f i represents the center frequency of the p-th hop signal; T p =T s [(p-1)N+1,...,pN-1,pN] represents the sampling time vector of the p-th hop signal, represents the transmit phase noise vector in the p-th hop signal, θ Tx [m] is the transmit phase noise at the mth moment, T s Indicates the sampling time.

[0032] Phase noiseθ Tx [m] can be modeled as a Wiener process of irregular motion, and satisfies the following equation:

[0033]

[0034] Among them, θ Tx [0] = 0, Δ Tx [i] has a mean of zero and a variance of Gaussian distribution, represents the single sideband 3dB coherence bandwidth of the transmitting frequency oscillator, {Δ Tx [i]} is a set of independent and identically distributed Gaussian random variables.

[0035] Furthermore, in step S2, at the frequency hopping communication receiver, after frequency hopping synchronization is performed on the received signal, the obtained p-th hop baseband symbiotic signal can be expressed as:

[0036]

[0037] Among them, h p represents the channel attenuation between the transmitter and receiver of a frequency hopping communication. represents an N-dimensional received noise column vector, where the dimension N is consistent with the number of symbols per hop signal. express The equivalent baseband form of , w[m] represents the equivalent baseband form of thermal noise at the mth moment. represents the phase noise vector in the pth frequency-hopping carrier at the receiver, represents the received phase noise at the mth moment, Δ Rx [i] has a mean of zero and a variance of Gaussian distribution, represents the single sideband 3dB coherence bandwidth of the frequency oscillator in the receiver, {Δ Rx [i]} is a set of independent and identically distributed Gaussian random variables.

[0038] Furthermore, step S3 specifically includes the following contents:

[0039] S301, assuming that the period of the frequency hopping pattern is N p The first hop is a synchronization hop for frequency hopping synchronization. The phase noise is estimated by using the synchronization hop. The estimated phase noise vector is:

[0040]

[0041] Among them, r1 represents the baseband symbiotic signal, x1 * represents the conjugate of the desired signal vector in the transmitted signal, ∠(·) represents the phase of (·), h1 represents the channel attenuation between the frequency hopping communication transmitter and the receiver, and I N represents an N-dimensional unit vector, Represents the phase noise estimation value at the mth moment. ∈1 is an N-dimensional column vector, representing the error vector of the phase noise estimation.

[0042] Therefore, the average estimate of the phase noise during a sync hop is:

[0043]

[0044] The reason why equation (a) is valid is that the Wiener phase noise process is a random process with continuous values.

[0045] S302: Considering that the transmitting and receiving phase noises are independent of each other, the increment of the transmitting phase noise It has a mean of zero and a variance of Gaussian distribution, the increment of the received phase noise θ Rx [m]-θ Rx [m-1] has a mean of zero and a variance of Gaussian distribution, so the joint phase noise increment of the transmitter and receiver is θ Tx [m]-θ Tx[m-1]-θ Rx [m]+θ Rx [m-1] has a mean of zero and a variance of At the receiving end, it is not necessary to estimate the 3dB correlation bandwidth of the receiving and transmitting frequency oscillators separately, but only the joint 3dB coherence bandwidth of the transmitting and receiving frequency oscillators needs to be estimated. Then, the estimated value is The expression is:

[0046]

[0047] At this point, the estimation of the phase noise level is completed.

[0048] The performance of the proposed phase noise level estimation method is simulated, where the normalized 3dB coherence bandwidth is set to B3 dB =10 -3 The simulation results are as follows: Figure 2 As shown in the figure, the black simulation curve represents the actual change trajectory of the phase noise, and the gray simulation dotted curve represents the change trajectory of the phase noise estimated by the method proposed in the present invention. It can be found that the proposed method can accurately estimate the level of the transmitting and receiving phase noise.

[0049] In summary, in view of the problem of signal distortion caused by phase noise in frequency hopping communication, the phase noise level estimation method proposed in this invention can improve the efficiency of phase noise level estimation at the cost of less resource consumption, which has important guiding significance for the development of practical engineering. The simulation results preliminarily verify the effectiveness and feasibility of this method.

[0050] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used for various other combinations, modifications and improvements, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A phase noise level estimation method, characterized in that: The method comprises: S1, the frequency hopping communication transmitter performs digital-to-analog conversion and frequency hopping modulation on the desired signal and then transmits it; S2, the frequency hopping communication receiver performs frequency hopping synchronization and analog-to-digital conversion on the received signal in sequence to obtain a digital baseband signal; S3. The frequency hopping communication receiver uses the synchronization hopping information to estimate the phase noise level.

2. A phase noise level estimation method according to claim 1, characterized in that: In S1, at the frequency hopping communication transmitter, the signal vector transmitted at the pth hop is expressed as: in, represents the Hadamard product, y[m] represents the symbol sent at the mth time, (p-1)N+1≤m≤pN, N represents the number of symbols per hop, (·) T represents the transpose operation, X p represents the expected signal vector in the p-th hop transmitted signal, f i represents the center frequency of the p-th hop signal, T p represents the sampling time vector of the p-th hop signal, represents the transmit phase noise vector in the p-th hop signal, θ Tx [m] is the transmit phase noise at the mth moment; Phase noiseθ Tx [m] is modeled as a Wiener process of irregular motion, and satisfies the formula: Among them, Δ Tx [i] is a set of independent and identically distributed Gaussian random variables.

3. A phase noise level estimation method according to claim 2, characterized in that: In S2, at the frequency hopping communication receiver, after frequency hopping synchronization is performed on the received signal, the obtained p-th hop baseband symbiotic signal is expressed as: Among them, h p represents the channel attenuation between the transmitter and receiver of a frequency hopping communication. represents the N-dimensional received noise column vector, where the dimension N is consistent with the number of symbols per hop signal N, and w p express The equivalent baseband form of represents the phase noise vector in the pth frequency hopping carrier at the receiver.

4. A phase noise level estimation method according to claim 3, characterized in that: The steps of S3 include the following: S301, set the period of the frequency hopping pattern to N p The first hop is a synchronization hop for frequency hopping synchronization. The phase noise is estimated by using the synchronization hop. The estimated phase noise vector is The average estimate of the phase noise during a synchronization hop is Among them, r1 represents the baseband symbiotic signal, x1 * represents the conjugate of the desired signal vector in the transmitted signal, ∠(·) represents the phase of (·), h1 represents the channel attenuation between the frequency hopping communication transmitter and the receiver, and I N represents an N-dimensional unit vector, represents the phase noise estimation value at the mth moment, ∈1 is an N-dimensional column vector, representing the error vector of the phase noise estimation; S302, because the phase noise of the transmission and reception are independent of each other, the increments of the transmission phase noise and the reception phase noise obey the Gaussian distribution, so the increment of the joint phase noise of the transmission and reception obeys the Gaussian distribution, and only the joint 3dB coherence bandwidth of the transmission and reception frequency oscillators is estimated at the receiving end. Record it as That is to complete the estimation of the phase noise level. represents the single sideband 3dB coherence bandwidth of the frequency oscillator in the receiver, It represents the single sideband 3dB coherence bandwidth of the transmitting frequency oscillator.

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