Phase noise trajectory tracking and suppression method

Abstract

The invention relates to a phase noise trajectory tracking and suppression method. The method comprises the following steps: step 1, carrying out mathematical representation on a communication transmitting signal, a wireless propagation channel and a communication receiving signal of a frequency hopping cooperative system; and step 2, at a communication receiver, estimating average channel fading and a phase noise value in the synchronization hop, and carrying out phase noise trajectory tracking and suppression on the signal hop. According to the method, the phase noise track of the signal hop is estimated by using the synchronization hop information, the phase noise in the transmitting and receiving frequency oscillator can be effectively suppressed, and the method has important guiding significance for radio frequency hardware error suppression in actual engineering.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a phase noise trajectory tracking and suppression method. Background Art

[0002] Frequency hopping technology is used in cooperative frequency hopping systems to avoid electromagnetic interference, and cooperative interference technology is used to block illegal eavesdropping, which can provide high-quality security services for wireless communication systems; however, the hopping RF carrier will cause significant phase noise at the transmitting and receiving frequency oscillators, resulting in distortion of the desired signal, degradation of cooperative interference suppression performance, and deterioration of the communication reception signal-to-noise ratio performance; therefore, how to effectively suppress the phase noise in the transmitting and receiving frequency oscillators is a problem that needs to be considered at present. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a phase noise trajectory tracking and suppression method to solve the deficiencies of the prior art.

[0004] The object of the present invention is achieved by the following technical solution: a phase noise trajectory tracking and suppression method, the method comprising:

[0005] Step 1: mathematically characterize the communication transmission signal, wireless propagation channel and communication reception signal of the frequency hopping cooperative system;

[0006] Step 2: At the communication receiver, the average channel fading and phase noise value in the synchronization jump is estimated, and the phase noise trajectory of the signal jump is tracked and suppressed.

[0007] The step 1 specifically includes:

[0008] At the communication transmitter, the baseband desired signal and cooperative interference are transmitted after weighted superposition, digital-to-analog conversion and frequency hopping modulation. The k-hop RF transmission signal is recorded as Where x(t) and y(t) represent the baseband desired signal and cooperative interference, respectively. x With P y They represent the transmission power of the two, respectively, i represents the carrier frequency of the k-th hop signal, represents the transmit phase noise;

[0009] Assume that the transmitted signal reaches the receiver after experiencing flat slow fading, and the channel fading is h;

[0010] At the communication receiver, the frequency hopping received signal is synchronized to obtain a digital baseband signal. in represents the analog-to-digital conversion operation, w(t) represents the noise component, x[n], y[n], They represent x(t), y(t), The discrete form of Represents the discrete form of the baseband equivalent noise signal.

[0011] The estimating, at the communication receiver, average channel fading and phase noise values ​​in synchronization hops comprises:

[0012] The average channel fading and phase noise parameters of the synchronization hop are estimated based on the expected signal sequence and cooperative interference information in the synchronization hop known to the receiver, and the estimated values ​​of the average signal fading and phase noise parameters are obtained as follows: Where N represents the number of symbols in each hop signal;

[0013] Setting the estimate The amplitude and phase are and but and Here, |·| represents a modulo operation, and ∠(·) represents a phase operation.

[0014] The phase noise trajectory tracking and suppression of the signal jump includes:

[0015] Using the estimated value of the (p-1)th jump Tracking the average phase noise in the received signal at the pth hop The estimated value of the average phase noise in the p-hop received signal is in, represents the average phase noise increment of the p-th hop received signal compared to the p-1-th hop signal;

[0016] Using the average phase noise estimate Perform phase noise suppression and cooperative interference separation to obtain the signal:

[0017]

[0018] The present invention has the following advantages: a phase noise trajectory tracking and suppression method, which uses synchronization jump information to estimate the phase noise trajectory of signal jumps, can effectively suppress the phase noise in the transmitting and receiving frequency oscillators, and has important guiding significance for the suppression of RF hardware errors in practical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of the present invention;

[0020] Figure 2 This is a simulation diagram of the bit error rate performance after phase noise suppression. DETAILED DESCRIPTION

[0021] 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.

[0022] like Figure 1 As shown, the present invention specifically relates to a phase noise trajectory tracking and suppression method, which effectively suppresses the phase noise in the transmitting and receiving frequency oscillators at the cost of less resource consumption; specifically includes the following contents:

[0023] S1. mathematically characterize the communication transmission signal, wireless propagation channel, and communication reception signal of the frequency hopping cooperative system;

[0024] S2, at the communication receiver, estimating the average channel fading and phase noise value in the synchronization hop;

[0025] S3. At the communication receiver, the phase noise trajectory of the signal jump is tracked and suppressed.

[0026] Furthermore, step S1 includes the following sub-steps:

[0027] S101, at the communication transmitter, the baseband desired signal and the cooperative interference are transmitted after weighted superposition, digital-to-analog conversion, and frequency hopping modulation. The k-th hop RF transmission signal is denoted as z k (t), the expression is:

[0028]

[0029] Where x(t) and y(t) represent the baseband desired signal and cooperative interference, respectively. x With P y They represent the transmission power of the two, respectively, i represents the carrier frequency of the k-th hop signal, represents the transmit phase noise.

[0030] S102. Assume that the transmitted signal reaches the receiver after experiencing flat slow fading, and denote the channel fading as h.

[0031] S103, at the communication receiver, frequency hopping synchronization is performed on the frequency hopping received signal to obtain a digital baseband signal rk [n], the mathematical expression is:

[0032]

[0033] in represents the analog-to-digital conversion operation, w(t) represents the noise component, x[n], y[n], They represent x(t), y(t), The discrete form of Represents the discrete form of the baseband equivalent noise signal.

[0034] It can be found that the baseband desired signal and cooperative interference include the transmit and receive phase noise terms, which will cause significant signal distortion.

[0035] Furthermore, in step S2, the expected signal sequence and the cooperative interference information in the synchronization hop are known to the receiver, which can be used to estimate the average channel fading and phase noise parameters of the synchronization hop. The estimated values ​​of the average channel fading and phase noise parameters are recorded as The expression is:

[0036]

[0037] Where N is the number of symbols in each hop signal. The reason why approximation (a) is true is that the baseband equivalent noise signal The power is much smaller than the baseband desired signal and the cooperative interference and signal of power.

[0038] Note the estimated value The amplitude and phase are and but and Here, |·| represents a modulo operation, and ∠(·) represents a phase operation.

[0039] Furthermore, step S3 includes the following sub-steps:

[0040] S301, the design of phase noise trajectory tracking and suppression algorithm is mainly based on two considerations: ① The accumulated phase error caused by phase noise in a short time is small, so there is no need to estimate the phase noise symbol by symbol. Phase noise suppression on a hop by hop basis can achieve better performance improvement; ② The Wiener phase noise process is a random process with continuous values. The average phase noise in the p-th hop received signal is The estimated value of the (p-1)th jump can be used Therefore, the estimated value of the average phase noise in the p-th hop received signal is:

[0041]

[0042] in, It represents the average phase noise increment of the p-th hop received signal compared to the p-1-th hop signal. Considering that the Wiener phase noise is a random process with independent increments, it can be directly obtained by traversing The approximate optimal solution of .

[0043] S302, using phase noise estimation value After phase noise suppression and cooperative interference separation, the resulting signal can be expressed as:

[0044]

[0045] Among them, the reason why approximation (b) is true is And the noise component The power is much smaller than the desired signal power.

[0046] The above formula shows that after the phase noise suppression and cooperative interference separation operations, the phase noise in the desired signal can be effectively suppressed and the cover signal can be separated almost perfectly.

[0047] The performance of the proposed phase noise trajectory tracking and suppression method is simulated, and the simulation results are as follows: Figure 2 As shown. It can be found that when phase noise exists in the system but no phase noise suppression is performed, the system bit error rate will reach 50% and the communication link will be blocked. The classical least squares algorithm only uses synchronization jumps for channel estimation and compensation. It can be found that when the normalized 3dB coherence bandwidth is less than 10 -7 When the phase noise is low, this method can suppress the phase noise well; however, as the phase noise level rises, the system bit error rate performance deteriorates sharply, because the phase error caused by the phase noise accumulates quickly, and only using synchronization jumps for channel compensation cannot meet the system performance requirements. The phase noise suppression method proposed in this patent has a system bit error rate that is much lower than the bit error rate of the classical least squares method, which verifies that the present invention has significant performance advantages.

[0048] In view of the problem that the hopping RF carrier will cause significant phase noise in the transmitting and receiving frequency oscillators, and the problem that the phase noise of frequency hopping communication causes distortion of the desired signal, degradation of cooperative interference suppression performance, and deterioration of the communication reception signal-to-noise ratio performance, the phase noise trajectory tracking and suppression method proposed in the present invention can improve the phase noise suppression capability in the transmitting and receiving frequency oscillators at the cost of less resource consumption, which has important guiding significance for the suppression of RF hardware errors in actual engineering.

[0049] 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 trajectory tracking and suppression method, characterized in that: The method comprises: Step 1: mathematically characterize the communication transmission signal, wireless propagation channel and communication reception signal of the frequency hopping cooperative system; Step 2: At the communication receiver, the average channel fading and phase noise value in the synchronization jump is estimated, and the phase noise trajectory of the signal jump is tracked and suppressed.

2. A phase noise trajectory tracking and suppression method according to claim 1, characterized in that: The step 1 specifically includes: At the communication transmitter, the baseband desired signal and cooperative interference are transmitted after weighted superposition, digital-to-analog conversion and frequency hopping modulation. The k-hop RF transmission signal is recorded as Where x(t) and y(t) represent the baseband desired signal and cooperative interference, respectively. x With P y They represent the transmission power of the two, respectively, i represents the carrier frequency of the k-th hop signal, represents the transmit phase noise; Assume that the transmitted signal reaches the receiver after experiencing flat slow fading, and the channel fading is h; At the communication receiver, the frequency hopping received signal is synchronized to obtain a digital baseband signal. in represents the analog-to-digital conversion operation, w(t) represents the noise component, x[n], y[n], They represent x(t), y(t), The discrete form of Represents the discrete form of the baseband equivalent noise signal.

3. A phase noise trajectory tracking and suppression method according to claim 2, characterized in that: The estimating, at the communication receiver, average channel fading and phase noise values ​​in synchronization hops comprises: The average channel fading and phase noise parameters of the synchronization hop are estimated based on the expected signal sequence and cooperative interference information in the synchronization hop known to the receiver, and the estimated values ​​of the average signal fading and phase noise parameters are obtained as follows: Where N represents the number of symbols in each hop signal; Setting the estimate The amplitude and phase are and but and Here, |·| represents a modulo operation, and ∠(·) represents a phase operation.

4. A phase noise trajectory tracking and suppression method according to claim 3, characterized in that: The phase noise trajectory tracking and suppression of the signal jump includes: Using the estimated value of the (p-1)th jump Tracking the average phase noise in the received signal at the pth hop The estimated value of the average phase noise in the p-hop received signal is in, represents the average phase noise increment of the p-th hop received signal compared to the p-1-th hop signal; Using the average phase noise estimate Perform phase noise suppression and cooperative interference separation to obtain the signal:

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