A channel compensation method for large bandwidth frequency hopping signals

Abstract

The present invention provides a channel compensation method for large-bandwidth frequency-hopping signals, comprising: step 1, generating a frequency-hopping pattern for a measurement signal; step 101, generating a uniform sequence; step 102, randomization processing; step 103, frequency mapping; step 2, up-conversion; step 3, down-conversion; step 4, estimating the amplitude and phase of the measurement signal; step 5, matrix loop filtering; and step 6, linear interpolation and compensation. The present invention proposes a scheme for generating a frequency-hopping pattern for a measurement signal by a method of mixed interpolation processing of uniform sequences and random sequences, while ensuring both the uniformity required for measurement and the randomness required for frequency-hopping communication. The present invention proposes a scheme for performing amplitude estimation and loop filtering on the measurement signal at the receiving end, and completing channel compensation for a large frequency-hopping bandwidth through linear interpolation. Amplitude and phase compensation for a large-bandwidth channel can be completed during the communication process without requiring additional hardware costs, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite communications, relates to large-bandwidth frequency-hopping signals, and particularly relates to a channel compensation method for large-bandwidth frequency-hopping signals. Background Art

[0002] Frequency-hopping communication technology, due to its excellent anti-interference capabilities, is widely used in satellite anti-interference communications, covert communications, electronic countermeasures, and other fields. In a frequency-hopping system, the transmitter uses a hopping pattern to retrieve a frequency control code from a frequency-hopping frequency table, controlling the transmitted signal to hop across a wider frequency band, thereby enhancing anti-interference and anti-interception capabilities.

[0003] In existing frequency-hopping communication systems, the frequency-hopping bandwidth typically ranges from 100 MHz to 2 GHz. As the frequency-hopping bandwidth increases, channel characteristics, particularly amplitude and phase mismatches at large bandwidths, hinder the receiver's ability to achieve optimal performance when recovering the frequency-hopping signal. These issues significantly hinder the application of wide-bandwidth frequency-hopping technology. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the object of the present invention is to provide a channel compensation method for large-bandwidth frequency-hopping signals to solve the technical problem of amplitude-phase inconsistency under large bandwidth in the prior art frequency-hopping communication system.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A channel compensation method for a large-bandwidth frequency-hopping signal, the method comprising the following steps:

[0007] Step 1: Generate the frequency hopping pattern of the measurement signal:

[0008] Step 101, uniform sequence generation:

[0009] Use m sequence to generate uniform sequence;

[0010] Step 102, randomization processing:

[0011] First, a random base sequence is generated, and then the uniform sequence obtained in step 101 is operated on the random base sequence to complete the randomization process and obtain a randomized sequence;

[0012] Step 103, frequency mapping:

[0013] Performing frequency mapping on the randomized sequence obtained in step 102 to complete the generation of a frequency hopping pattern for the measurement signal;

[0014] Step 2: Up-conversion:

[0015] At the transmitting end, the measurement signal needs to be up-converted, and the local oscillator of the up-conversion is the frequency point corresponding to the frequency hopping pattern of the measurement signal generated in step 1;

[0016] Step 3: down-conversion;

[0017] At the receiving end, the signal needs to be down-converted to recover the baseband measurement signal;

[0018] Step 4: Estimation of amplitude and phase of the measurement signal;

[0019] Performing amplitude estimation and phase estimation on the frequency hopping signal obtained at the receiving end after down-conversion in step 3 to obtain an amplitude estimation value and a phase estimation value;

[0020] Step 5: Matrix loop filtering;

[0021] Performing first-order loop filtering on the amplitude estimation value and the phase estimation value obtained in step 4 to obtain a filtered amplitude estimation value and a filtered phase estimation value;

[0022] Step 6: Linear interpolation and compensation:

[0023] The filtered amplitude estimation value and the filtered phase estimation value obtained in step 5 are linearly interpolated and compensated to form amplitude and phase error curves of the large bandwidth channel.

[0024] Compared with the prior art, the present invention has the following technical effects:

[0025] (I) The present invention proposes a scheme for generating a frequency hopping pattern for a measurement signal by a method of mixed interpolation processing of uniform sequences and random sequences, while ensuring both the uniformity required for measurement and the randomness required for frequency hopping communication.

[0026] (II) This invention proposes a scheme for channel compensation in wide frequency-hopping bandwidths, using linear interpolation to perform amplitude estimation and loop filtering on the measured signal at the receiving end. This scheme can achieve amplitude and phase compensation for wide-bandwidth channels during communication without requiring additional hardware, and has promising application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a principle block diagram of the channel compensation method for large-bandwidth frequency-hopping signals of the present invention.

[0028] The specific contents of the present invention are further explained in detail below with reference to the embodiments. DETAILED DESCRIPTION

[0029] It should be noted that, unless otherwise specified, all sequences and methods in the present invention adopt sequences and methods known in the prior art.

[0030] In the present invention, a large bandwidth frequency hopping signal refers to a frequency hopping signal greater than 2 GHz.

[0031] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0032] Example:

[0033] This embodiment provides a channel compensation method for large bandwidth frequency hopping signals, such as Figure 1 As shown, the method includes the following steps:

[0034] Step 1: Generate the frequency hopping pattern of the measurement signal:

[0035] Step 1 includes the following steps:

[0036] Step 101, uniform sequence generation:

[0037] In this step, in order to ensure basic measurement performance, the measurement signal should be evenly distributed in the entire frequency band within the period time. The uniform sequence generation uses a typical m-sequence, which has the characteristic of periodicity.

[0038] Use m sequence to generate uniform sequence;

[0039] In step 101, the input conditions of the uniform sequence are the uniform sequence period L and the sequence initial phase. The set X of the output sequence of the uniform sequence can be expressed as:

[0040] X={x i}, where i∈[0,L-1]

[0041] Where:

[0042] x i represents the generated uniform sequence;

[0043] i represents the serial number;

[0044] L represents the uniform sequence period.

[0045] In step 101, the method for generating the uniform sequence is:

[0046]

[0047] Where:

[0048] [c1c2…c n ] represents the coefficients of the m-sequence generating polynomial;

[0049] n represents the number of m-sequence shift registers.

[0050] Step 102, randomization processing:

[0051] In this step, in order to ensure the concealment performance of frequency hopping communication, the generated uniform sequence needs to be randomized.

[0052] First, a random base sequence is generated, and the uniform sequence obtained in step 101 is operated on the random base sequence to complete the randomization process and obtain a randomized sequence;

[0053] In step 102, the set Y of random base sequences is expressed as:

[0054] Y={y j}, where j∈[0,Q-1]

[0055]

[0056] Where:

[0057] y j represents the generated random base sequence;

[0058] j represents the serial number;

[0059] Q represents the value range of the sequence number of the random base sequence;

[0060] BW represents the system frequency hopping bandwidth;

[0061] SP min Indicates the minimum frequency hopping interval;

[0062] L represents the uniform sequence period.

[0063] In step 102, the set Z of randomized sequences is expressed as:

[0064]

[0065] Where:

[0066] z m represents the sequence after randomization;

[0067] m represents the sampling point number.

[0068] In this step, it should be noted that x i with y j The hopping frequency is different, y j The hopping frequency is the system hopping rate, but x i The hopping frequency is the ratio of the system frequency hopping rate to Q.

[0069] In this step, typical methods for generating random base sequences include Gold sequence, chaotic sequence, etc. In this embodiment, there is no restriction on the method for generating the base sequence.

[0070] Step 103, frequency mapping:

[0071] The randomized sequence obtained in step 102 is frequency mapped to complete the generation of the measurement signal frequency hopping pattern.

[0072] In step 103, the mapping process is as follows:

[0073]

[0074] Where:

[0075] F m Indicates the actual output frequency;

[0076] F0 represents the starting frequency of the available bandwidth;

[0077] BW represents the available frequency bandwidth;

[0078] SP min Indicates the minimum frequency hopping interval;

[0079] z m Represents the sequence after randomization.

[0080] Step 2: Up-conversion:

[0081] At the transmitting end, the measurement signal needs to be up-converted, and the local oscillator for the up-conversion is the frequency point corresponding to the frequency hopping pattern of the measurement signal generated in step 1.

[0082] In step 2, the frequency hopping signal S after up-conversion at the transmitter uc Expressed as:

[0083] S uc =s(t)*exp(j2πf m t)+n(t)

[0084] Where:

[0085] s(t) represents the input signal;

[0086] j is the imaginary number symbol;

[0087] exp() represents the natural exponential function;

[0088] f m Indicates the real-time frequency hopping frequency;

[0089] n(t) represents the system noise.

[0090] Step 3: down-conversion;

[0091] At the receiving end, the signal must be down-converted to restore the baseband measurement signal.

[0092] In step 3, the frequency hopping signal R after down-conversion at the receiving end uc (t) is expressed as:

[0093] R uc (t)=s(t)*ΔA e exp(jΔθ e t*T)+n(t)

[0094] Where:

[0095] s(t) represents the input signal;

[0096] j is the imaginary number symbol;

[0097] exp() represents the natural exponential function;

[0098] ΔA e represents the residual amplitude error;

[0099] Δθ e t represents the residual phase error.

[0100] T represents the signal period;

[0101] n(t) represents the system noise.

[0102] Step 4: Estimation of amplitude and phase of the measurement signal;

[0103] Performing amplitude estimation and phase estimation on the frequency hopping signal obtained at the receiving end after down-conversion in step 3 to obtain an amplitude estimation value and a phase estimation value;

[0104] In step 4, the method for estimating the amplitude and phase of the measurement signal is:

[0105]

[0106]

[0107] Where:

[0108] represents the phase estimate;

[0109] represents the magnitude estimate;

[0110] k is the frequency point number within the bandwidth;

[0111] t represents time;

[0112] R uc() represents the frequency hopping signal after down-conversion at the receiving end;

[0113] imag() represents the imaginary part function of a complex number;

[0114] real() represents a real-valued function;

[0115] abs() represents the absolute value function.

[0116] Step 5: Matrix loop filtering;

[0117] Performing first-order loop filtering on the amplitude estimation value and the phase estimation value obtained in step 4 to obtain a filtered amplitude estimation value and a filtered phase estimation value;

[0118] In this step, different filtering dimensions are maintained at different frequency points. Matrix loop filtering can effectively avoid the impact of single-point abnormal jumps. Considering the complexity of implementation, matrix filtering adopts a first-order loop filtering solution.

[0119] In step 5, the first-order loop filtering method is:

[0120]

[0121]

[0122] Where:

[0123] represents the phase estimate;

[0124] represents the phase estimate after filtering;

[0125] represents the magnitude estimate;

[0126] represents the amplitude estimate after filtering;

[0127] k is the frequency point number within the bandwidth;

[0128] t represents time;

[0129] a represents the loop filter coefficient;

[0130] Step 6: Linear interpolation and compensation.

[0131] The filtered amplitude estimation value and the filtered phase estimation value obtained in step 5 are linearly interpolated and compensated to form amplitude and phase error curves of the large bandwidth channel.

[0132] In step six, the linear difference and compensation method is:

[0133]

[0134]

[0135] Where:

[0136] θ e (m,t) represents the final amplitude error curve;

[0137] represents the phase estimate after filtering;

[0138] A e (m, t) represents the final phase error curve;

[0139] represents the amplitude estimate after filtering;

[0140] k is the frequency point number within the bandwidth;

[0141] t represents time;

[0142] M represents the number of sampling points between two estimated values;

[0143] m represents the sampling point number.

[0144] The present invention generates a frequency hopping pattern for the measurement signal through a method of mixed interpolation processing of uniform sequences and random sequences, while ensuring the uniformity required for measurement and the randomness required for frequency hopping communication; at the receiving end, the measurement signal is amplitude estimated and loop filtered, and channel compensation under large frequency hopping bandwidth is completed through linear interpolation.

[0145] The present invention overcomes the problems of amplitude and phase inconsistency under large bandwidth in existing frequency hopping communication systems, and can complete the compensation of large bandwidth channel amplitude and phase during the communication process without additional hardware cost, and has good application prospects.

Claims

1. A channel compensation method for a large bandwidth frequency hopping signal, characterized in that: The method comprises the following steps: Step 1: Generate the frequency hopping pattern of the measurement signal: Step 101, uniform sequence generation: Use m sequence to generate uniform sequence; Step 102, randomization processing: First, a random base sequence is generated, and then the uniform sequence obtained in step 101 is operated on the random base sequence to complete the randomization process and obtain a randomized sequence; Step 103, frequency mapping: Performing frequency mapping on the randomized sequence obtained in step 102 to complete the generation of a frequency hopping pattern for the measurement signal; Step 2: Up-conversion: At the transmitting end, the measurement signal needs to be up-converted, and the local oscillator of the up-conversion is the frequency point corresponding to the frequency hopping pattern of the measurement signal generated in step 1; Step 3: down-conversion; At the receiving end, the signal needs to be down-converted to recover the baseband measurement signal; Step 4: Estimation of amplitude and phase of the measurement signal; Performing amplitude estimation and phase estimation on the frequency hopping signal obtained at the receiving end after down-conversion in step 3 to obtain an amplitude estimation value and a phase estimation value; Step 5: Matrix loop filtering; Performing first-order loop filtering on the amplitude estimation value and the phase estimation value obtained in step 4 to obtain a filtered amplitude estimation value and a filtered phase estimation value; Step 6: Linear interpolation and compensation: The filtered amplitude estimation value and the filtered phase estimation value obtained in step 5 are linearly interpolated and compensated to form amplitude and phase error curves of the large bandwidth channel.

2. The channel compensation method for a large bandwidth frequency hopping signal according to claim 1, wherein: In step 101, the input conditions of the uniform sequence are the uniform sequence period L and the sequence initial phase. The set X of the output sequence of the uniform sequence can be expressed as: X={x i }, where i∈[0,L-1] Where: x i represents the generated uniform sequence; i represents the serial number; L represents the uniform sequence period; In step 101, the method for generating the uniform sequence is: Where: [c1c2…c n ] represents the coefficients of the m-sequence generating polynomial; n represents the number of m-sequence shift registers.

3. The channel compensation method for a large bandwidth frequency hopping signal according to claim 1, wherein: In step 102, the set Y of random base sequences is expressed as: Y={y j }, where j∈[0,Q-1] Where: y j represents the generated random base sequence; j represents the serial number; Q represents the value range of the sequence number of the random base sequence; BW represents the system frequency hopping bandwidth; SP min Indicates the minimum frequency hopping interval; L represents the uniform sequence period; In step 102, the set Z of randomized sequences is expressed as: Where: z m represents the sequence after randomization; m represents the sampling point number.

4. The channel compensation method for a large bandwidth frequency hopping signal according to claim 1, wherein: In step 103, the mapping process is as follows: Where: F m Indicates the actual output frequency; F0 represents the starting frequency of the available bandwidth; BW represents the available frequency bandwidth; SP min Indicates the minimum frequency hopping interval; z m Represents the sequence after randomization.

5. The channel compensation method for a large bandwidth frequency hopping signal according to claim 1, wherein: In step 2, the frequency hopping signal S after up-conversion at the transmitter uc Expressed as: S uc =s(t)*exp(j2πf m t)+n(t) Where: s(t) represents the input signal; exp() represents the natural exponential function; j is the imaginary number symbol; f m Indicates the real-time frequency hopping frequency; n(t) represents the system noise.

6. The channel compensation method for a large bandwidth frequency hopping signal according to claim 1, wherein: In step 3, the frequency hopping signal R after down-conversion at the receiving end uc (t) is expressed as: R uc (t)=s(t)*ΔA e exp(jΔθ e t*T)+n(t) Where: s(t) represents the input signal; j is the imaginary number symbol; exp() represents the natural exponential function; ΔA e represents the residual amplitude error; Δθ e t represents the residual phase error; T represents the signal period; n(t) represents the system noise.

7. The channel compensation method for a large bandwidth frequency hopping signal according to claim 1, wherein: In step 4, the method for estimating the amplitude and phase of the measurement signal is: Where: represents the phase estimate; represents the magnitude estimate; k is the frequency point number within the bandwidth; t represents time; R uc ( ) represents the frequency hopping signal after down-conversion at the receiving end; imag() represents the imaginary part function of a complex number; real() represents a real-valued function; abs() represents the absolute value function.

8. The channel compensation method for a large bandwidth frequency hopping signal according to claim 1, wherein: In step 5, the first-order loop filtering method is: Where: represents the phase estimate; represents the phase estimate after filtering; represents the magnitude estimate; represents the amplitude estimate after filtering; k is the frequency point number within the bandwidth; t represents time; a represents the loop filter coefficient.

9. The channel compensation method for a large bandwidth frequency hopping signal according to claim 1, wherein: In step six, the linear difference and compensation method is: Where: θ e (m, t) represents the final amplitude error curve; represents the phase estimate after filtering; A e (m, t) represents the final phase error curve; represents the amplitude estimate after filtering; k is the frequency point number within the bandwidth; t represents time; M represents the number of sampling points between two estimated values; m represents the sequence number of the sampling points.

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