A method for estimating phase noise level

Abstract

The present invention relates to a method for estimating phase noise level, belonging to the field of wireless communication. The method includes: 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 sequentially performs frequency hopping synchronization and analog-to-digital conversion on the received signal to obtain a digital baseband signal; S3. The frequency hopping communication receiver uses the synchronous hopping information to estimate the phase noise level. The present invention accurately estimates the phase noise level of the frequency oscillation device in the frequency hopping communication system at the cost of less resource consumption, and has important guiding significance for suppressing hardware errors in practical engineering.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication, and particularly to a method for estimating phase noise level. Background Art

[0002] Frequency hopping communication systems combat interference by changing the carrier frequency and have been widely applied in civil and military communication fields; however, the hopping carrier will cause significant phase 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 filtering algorithm to suppress phase noise; therefore, how to utilize the synchronous hopping information of the frequency hopping communication system to accurately estimate the phase noise level of the frequency oscillation device in the frequency hopping communication system at the cost of less resource consumption is a problem that needs to be considered currently. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art, and provides a method for estimating phase noise level, which solves the deficiencies existing in the prior art.

[0005] The purpose of the present invention is achieved through the following technical solutions: A method for estimating phase noise level, 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 sequentially performs frequency hopping synchronization and analog-to-digital conversion on the received signal to obtain a digital baseband signal;

[0008] S3. The frequency hopping communication receiver estimates the phase noise level by using the synchronous hopping information.

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

[0010]

[0011] Wherein, represents the Hadamard product, y[m] represents the symbol transmitted at the m-th moment, (p - 1)N + 1 ≤ m ≤ pN, N represents the number of symbols of each hop signal, (·) T represents the transpose operation, X p represents the desired signal vector in the signal transmitted in the p-th hop, 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 m-th moment;

[0012] Phase noise θ Tx [m] is modeled as a Wiener process of random motion and satisfies the formula:

[0013]

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

[0015] In step S2, at the frequency-hopping communication receiver, after frequency-hopping synchronization of the received signal, the p-th hop baseband co-generation signal obtained is expressed as:

[0016]

[0017] where, h p represents the channel attenuation between the frequency-hopping communication transmitter and the receiver, represents the N-dimensional received noise column vector, where the dimension N is the same as the number of symbols of each hop signal, w p represents the equivalent baseband form of represents the phase noise vector in the p-th hop carrier at the receiver.

[0018] The steps of step S3 include the following:

[0019] S301. Assume that the period of the frequency-hopping pattern is N p hops, and the first hop is a synchronization hop for frequency-hopping synchronization. Use the synchronization hop for phase noise estimation, and the estimated phase noise vector is The average estimated value of the phase noise in the synchronization hop is where, r1 represents the baseband co-generation 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, I N represents the N-dimensional unit vector, represents the phase noise estimated value at the m-th moment, ∈1 is the N-dimensional column vector representing the error vector of phase noise estimation;

[0020] S302. Because the transmit and receive phase noises are independent of each other, and the increments of both the transmit phase noise and the receive phase noise follow a Gaussian distribution, so the joint transmit-receive phase noise increment follows a Gaussian distribution. At the receiving end, only estimate the joint 3dB coherence bandwidth of the transmit-receive frequency oscillators Denote it as That is, the horizontal estimation of the phase noise is completed, Represents the single - sideband 3dB coherence bandwidth of the frequency oscillator in the receiver, Represents the single - sideband 3dB coherence bandwidth of the transmitting frequency oscillator.

[0021] The present invention has the following advantages: A method for estimating the phase noise level accurately estimates the phase noise level of the frequency oscillation device in the frequency - hopping communication system at the cost of less resource consumption, which has important guiding significance for suppressing hardware errors in practical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Is the flow schematic diagram of the present invention;

[0023] Figure 2 Is the performance simulation diagram of the phase noise level estimation. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to 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. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below with reference to the drawings in the present application is not intended to limit the protection scope of the present application claimed, but only represents the selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the protection scope of the present application. The present invention will be further described below with reference to the drawings.

[0025] As Figure 1 shown, the present invention realizes the effective estimation of the phase noise level through a method of using synchronous hopping information for phase noise level estimation. After converting the received signal into a digital baseband signal, the phase noise vector is estimated using synchronous hopping, and then the operation of 3dB coherence bandwidth estimation is performed; specifically, it includes the following content.

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

[0027] S2. The frequency - hopping communication receiver first performs frequency - hopping acquisition on the received signal in sequence, reducing 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 within the capture accuracy. Then, the frequency - hopping tracking operation is performed to complete frequency - hopping synchronization, and after analog - to - digital conversion, a digital baseband signal is obtained;

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

[0029] Furthermore, in step S1, considering the case where there is phase noise at the transmitting frequency oscillator, at the frequency hopping communication transmitter, the signal vector transmitted in the p-th hop can be expressed as:

[0030]

[0031] where p takes positive integer values, denotes the Hadamard product, y[m] represents the symbol transmitted at the m-th moment, (p - 1)N + 1 ≤ m ≤ pN, N represents the number of symbols in each hop signal, (·) T denotes the transpose operation; x p = [x[(p - 1)N + 1],..., x[pN - 1], x[pN]] T represents the desired signal vector in the p-th hop transmitted signal, x[m] represents the desired 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 transmitted phase noise vector in the p-th hop signal, θ Tx [m] is the transmitted phase noise at the m-th moment, T s represents the sampling time.

[0032] The phase noise θ Tx [m] can be modeled as a Wiener process of random motion and satisfies the following equation:

[0033]

[0034] where, θ Tx [0] = 0, Δ Tx [i] follows a Gaussian distribution with a mean of zero and a variance of , 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 of the received signal, the baseband coexisting signal obtained in the p-th hop can be expressed as:

[0036]

[0037] where h p represents the channel attenuation between the frequency hopping communication transmitter and the receiver, denotes an N - dimensional received noise column vector, where the dimension N is the same as the number of symbols per hop of the signal, denotes the equivalent baseband form of, w[m] denotes the equivalent baseband form of the thermal noise at the m - th moment. denotes the phase - noise vector in the p - th hopping carrier at the receiver, denotes the received phase noise at the m - th moment, Δ Rx [i] follows a Gaussian distribution with a mean of zero and a variance of denotes 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 content:

[0039] S301. Assume that the period of the hopping pattern is N p hops, and the first hop is a synchronization hop for frequency - hopping synchronization. Use the synchronization hop for phase - noise estimation, and the estimated phase - noise vector is:

[0040]

[0041] where r1 denotes the baseband co - existing signal, x1 * denotes the conjugate of the desired - signal vector in the transmitted signal, ∠(·) denotes the phase of (·), h1 denotes the channel attenuation between the frequency - hopping communication transmitter and the receiver, I N denotes an N - dimensional unit vector, denotes the phase - noise estimated value at the m - th moment. ∈1 is an N - dimensional column vector representing the error vector of phase - noise estimation.

[0042] Therefore, the average estimated value of the phase noise in the synchronization hop is:

[0043]

[0044] where the reason for the equality (a) in the formula holds because the Wiener phase - noise process is a continuous - valued random process.

[0045] S302. Considering that the phase noise between transmission and reception is independent of each other, the increment of the transmission phase noise follows a Gaussian distribution with a mean of zero and a variance of , the increment of the received phase noise θ Rx [m] - θ Rx [m - 1] follows a Gaussian distribution with a mean of zero and a variance of , so the joint transmit - receive phase - noise increment θ Tx [m] - θ Tx ​[m - 1] - θ Rx [m] + θ Rx [m - 1] follows a Gaussian distribution with a mean of zero and a variance of At the receiving end, it is not necessary to separately estimate the 3dB correlation bandwidth of the transmitter and receiver frequency oscillators. It is only necessary to estimate the combined 3dB coherence bandwidth of the transmitter and receiver frequency oscillators That's all. Denote its estimated value as The expression is:

[0046]

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

[0048] Perform performance simulation on the proposed phase noise level estimation method. The normalized 3dB coherence bandwidth is set to B3 dB = 10 -3 . The simulation results are as Figure 2 shown. In the figure, the black simulation curve represents the actual change trajectory of the phase noise, and the gray simulation dot 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 levels of the transmitted and received phase noises.

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

[0050] The above is only the preferred implementation mode of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and improvements, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in related fields. And the changes and modifications made by those skilled in the art that do not depart from the spirit and scope of the present invention should all be within the protection scope of the appended claims of the present invention.

Claims

1. A method for estimating phase noise level, characterized in that: The method includes: 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 sequentially performs frequency-hopping synchronization and analog-to-digital conversion on the received signal to obtain a digital baseband signal; S3. The frequency-hopping communication receiver estimates the phase noise level using the synchronous hopping information; In the above S1, at the frequency-hopping communication transmitter, the signal vector transmitted by the Among them, represents the Hadamard product, represents the symbol sent at time ([ p p -1) N +1 ≤ m ≤ pN , represents the number of symbols of each-hop signal, represents the transpose operation, X p represents the desired signal vector in the th-hop transmitted signal, represents the th-hop signal center frequency, T p represents the th-hop signal sampling time vector, represents the th-hop signal transmitted phase noise vector, is the transmitted phase noise at time; Phase noise Modeled as a Wiener process of random motion and satisfying the formula: wherein, is a set of independent and identically distributed Gaussian random variables; In S2, at the frequency hopping communication receiver, after frequency hopping synchronization of the received signal, the hopping baseband coexisting signal is expressed as: Among them, represents the channel attenuation between the frequency-hopping communication transmitter and the receiver, represents an N-dimensional received noise column vector, where the dimension is consistent with the number of symbols of each hop signal, w p represents the equivalent baseband form of represents the phase noise vector in the nth frequency-hopping carrier at the receiver.

2. The phase noise level estimation method according to claim 1, wherein: The steps of S3 include the following: S301. Set the period of the frequency hopping pattern as hops, and the first hop is a synchronization hop for frequency hopping synchronization. Use the synchronization hop to estimate the phase noise, and the estimated phase noise vector is . The average estimated value of the phase noise in the synchronization hop is . Among them, represents the baseband coexisting signal, represents the conjugate of the desired signal vector in the transmitted signal, represents 's phase, represents the channel attenuation between the frequency hopping communication transmitter and the receiver, represents dimensional unit vector, represents the phase noise estimated value at the m-th moment, is an N-dimensional column vector, representing the error vector of the phase noise estimation; S302. Since the phase noises of transmission and reception are independent of each other, and the increments of the transmission phase noise and the reception phase noise both follow a Gaussian distribution, the increment of the joint transmission and reception phase noise follows a Gaussian distribution. At the receiving end, only the joint 3 dB coherence bandwidth of the transmission and reception frequency oscillators is estimated , which is denoted as , that is, the horizontal estimation of the phase noise is completed. represents the single-sideband 3 dB coherence bandwidth of the frequency oscillator in the receiver, represents the single-sideband 3 dB coherence bandwidth of the transmission frequency oscillator.

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