CN105959246A - Anti-interference method - Google Patents

Abstract

The invention provides an anti-interference method comprising steps of: acquiring the optimal decision threshold value of a signal on the basis of the frequency division characteristic of OFDM technology used by a TD-LTE system; determining, by using the optimal decision threshold value, whether interference exists in a frequency-domain subcarrier corresponding to a signal received by the receiving end of the TD-LTE system, and reassigning, if yes, a signal carried by the subcarrier subjected to interference to the subcarrier without interference, namely reassigning the spectrum resource without interference. Thus, the anti-interference method may avoid interference when signals are transmitted to increase the reliability of signal transmission and achieve an anti-interference purpose.

Description

A kind of anti-interference method

Technical field

The present invention relates to areas of information technology, particularly to a kind of anti-interference method.

Background technology

Along with TD-LTE broadband wireless communication technique is at intelligent grid, the deepening continuously of special field such as national defense and military should With, the electromagnetic environment that broadband wireless communications private network is faced also becomes to become increasingly complex.At civil area, due to a large amount of different logical Communication system is widely used, and causes the relevant issues such as frequency spectrum resource anxiety and electromagnetic environment complexity.In military field, currently lead to Letter jamming equipment commonly used high-power, there is ability that is able to programme and that simultaneously disturb multiple target.Use multiple receiver, many Individual activator and the solid-state power amplifier of high-capacity transistor, and the antenna match of high-gain, can be simultaneously in the widest frequency In the range of monitor and disturb multiple radiation source, the general communication of high frequency, very high frequency(VHF) and hyperfrequency and frequency modulation communication can be had Effect interference.In communication system to be ensured each node in any place, the transmitting of information can be carried out any time, send out Waving the communication usefulness of maximum, broadband wireless communications private network must have the survival ability of tanacity.

Reliable communication to be ensured under following actual application scenarios, it is necessary to develop new electromagnetic environment quick sensing skill Art and Anti-Jamming Technique tackle electromagnetic environment complicated and changeable and interference means.Require system of broadband wireless communication pair simultaneously Frequency spectrum perception and multi-level Anti-Jamming Technique carry out integrated design, and the communication of such guarantee is anti-interference has specific aim and reality Shi Xing, it is ensured that information is reliably and effectively transmitted under complex electromagnetic environment.Therefore, Anti-Jamming Technique based on frequency spectrum perception is developed Be contemporary broadband wireless private network communication in the urgent need to, the reliability that private network communication works under complex electromagnetic environment can be ensured And effectiveness, it is key and the core of future wireless private network.

Existing spread spectrum perturbation technique mainly includes DS and frequency hopping two ways, when reality is applied, except needing extension Outside spectral bandwidth, also to previously generate and to each communication node distribution spread spectrum parameter, and only set up synchronization at receiving-transmitting sides The most just can communicate, this method takies substantial amounts of bandwidth and easily brings co-located interference problem, is participating in node Count in the communication network of more and dynamic foundation, generate the application mode shortage motility also spreading parameter with distribution, exist same The potential problems that step overlong time even cannot synchronize, reduce the reliability of communication.Additionally, those skilled in the art also adopt Give signal by adaptive antenna technology and disturb the direction difference transmitted, reaching jamproof mesh by adjusting antenna parameter , but realize adaptive antenna in HF/VHF/UHF frequency range and yet suffer from technological difficulties.

In sum, existing tradition anti-interference method is to lacking of property of TD-LTE system and effectiveness, it is difficult to meet TD- The jamproof needs of LTE system.

Summary of the invention

It is an object of the invention to provide a kind of anti-interference method, be applied to TD-LTE system solving existing anti-interference method Time there is lacking of property and the problem of effectiveness.

For solving above-mentioned technical problem, the present invention provides a kind of anti-interference method, and described anti-interference method includes:

Obtain the optimum decision threshold value of signal；

Utilize the frequency domain load that the signal of the receiving terminal reception of described optimum decision threshold value judgement TD-LTE system is corresponding Whether there is interference on ripple, if there is interference, then on the subcarrier being disturbed, the signal of carrying is reassigned to glitch-free Subcarrier.

Optionally, in described anti-interference method, the step of the optimum decision threshold value obtaining signal is as follows:

Build the binary detection model of awgn channel and set initial decision threshold threshold value；

False-alarm probability and detection probability is obtained based on described binary detection model and described initial decision threshold threshold value, described When false-alarm probability is the awgn channel free time, in awgn channel, the mean power of signal is more than the probability of initial decision threshold threshold value, institute State detection probability be awgn channel when there is CU in awgn channel the mean power of signal more than initial decision threshold threshold The probability of value；

Obtain the compromise probability suppressing virtual probability to obtain while increasing detection probability, push away according to described compromise probability is counter The mean power of signal as optimum decision thresholding threshold value.

Optionally, in described anti-interference method, the binary detection model of described awgn channel is:

$\left\{\begin{array}{c}{H}_0:r\left(t\right)=n\left(t\right)\\ H_1:r\left(t\right)=x\left(t\right)+n\left(t\right)\end{array}\right.$

Wherein, H₀Represent channel idle and there is no CU, H₁Representing that channel has CU, r (t) represents that channel connects The signal received, x (t) represents useful signal, and n (t) represents noise signal.

Optionally, in described anti-interference method, acquisition false-alarm probability employing equation below:

$P_F=P\{V_0>V_T^{\′}|H_0\}=p\{{\mathrm{\χ}}_{2TW}^2>V_T^{\′}\}$

Wherein, P_FRepresent false-alarm probability, V_T' represent initial decision threshold threshold value, H₀Represent channel idle and There is no CU, V₀The mean power of signal in awgn channel when representing the awgn channel free time,T table Showing the cycle, n (t) represents noise signal,H=2Wt-i,W represents bandwidth, n table Show the quantity of awgn channel.

Optionally, in described anti-interference method, under awgn channel, the expression formula of false-alarm probability is as follows:

$P_F=\frac{\mathrm{\Γ}(TW,\frac{V_T^{\′}}{2})}{\mathrm{\Γ}\left(TW\right)},$

Wherein, P_FExpression false-alarm probability, Γ (a, b) is incomplete gamma function, a=WT,V'_TRepresent initial Decision threshold threshold value, W represents that bandwidth, T represent the cycle.

Optionally, in described anti-interference method, acquisition detection probability employing equation below:

$P_D=P\{V_1>V_T^{\′}|H_1\}=p\{{\mathrm{\χ}}_{2TW}^2\left(\mathrm{\γ}\right)>V_T^{\′}\},$

Wherein, P_DRepresent detection probability, V_T' represent initial decision threshold threshold value, H₁Represent that channel has CU, V₁Table Show the mean power of signal when channel exists CU, N₀Represent signal Bilateral power spectral density, T represents the cycle, and x (t) represents useful signal,H=2Wt-i,X represents AWGN The quantity of channel.

Optionally, in described anti-interference method, under awgn channel, the expression formula of detection probability is as follows:

$P_D=Q_{TW}(\sqrt{2\mathrm{\γ}},\sqrt{V_T^{\′}}),$

Wherein, P_DRepresent detection probability, Q_u(a, b) is broad sense Marcum function, u=TW,W table Show bandwidth, V_TRepresenting initial decision threshold threshold value, T represents the cycle,X table Show the quantity of awgn channel, N₀Represent the bilateral power spectral density of signal.

Optionally, in described anti-interference method, described optimum decision threshold value judgement TD-LTE system is utilized to receive Hold the judgement standard that whether there is interference in the subcarrier in frequency domain that the signal received is corresponding as follows:

If the average power signal of the signal that TD-LTE system receiving terminal receives is more than described optimum decision threshold value, then Whether interference is there is in subcarrier in frequency domain corresponding to signal that TD-LTE system receiving terminal receives；

If the average power signal of the signal that TD-LTE system receiving terminal receives is less than or equal to described optimum decision threshold value, It is to there is not interference in the subcarrier in frequency domain that then signal of TD-LTE system receiving terminal reception is corresponding.

Optionally, in described anti-interference method, on the subcarrier that will be disturbed, the signal of carrying is reassigned to nothing The process of the subcarrier of interference comprises the steps:

Do not give the subcarrier distribution modulation symbol being disturbed；

It is mapped on glitch-free subcarrier after signal modulation on the subcarrier that will be disturbed.

In anti-interference method provided by the present invention, frequency division spy based on the OFDM technology that TD-LTE system is used Property, first obtain the optimum decision threshold value of signal；Then, the reception of described optimum decision threshold value judgement TD-LTE system is utilized Holding and whether there is interference in the subcarrier in frequency domain that the signal received is corresponding, if there is interference, then holding on the subcarrier being disturbed The signal carried is reassigned to glitch-free subcarrier, i.e. redistributes glitch-free frequency spectrum resource, thus when signal transmits Avoid interference, to improve the reliability of signal transmission, reach jamproof purpose.

Accompanying drawing explanation

Fig. 1 is the flow chart of the anti-interference method of one embodiment of the invention；

Fig. 2 is the flow chart of the optimum decision threshold value obtaining signal in one embodiment of the invention.

Detailed description of the invention

The anti-interference method proposed the present invention below in conjunction with the drawings and specific embodiments is described in further detail.According to Explanation and claims below, advantages and features of the invention will be apparent from.It should be noted that, accompanying drawing all uses and simplifies very much Form and all use non-ratio accurately, only in order to convenient, aid in illustrating the purpose of the embodiment of the present invention lucidly.

Refer to Fig. 1, it is the flow chart of anti-interference method of the present invention, as it is shown in figure 1, described anti-interference method, bag Include:

First, perform step S1, obtain the optimum decision threshold value of signal；

Then, perform step S2, utilize the letter that the receiving terminal of described optimum decision threshold value judgement TD-LTE system receives Whether interference is there is in number corresponding subcarrier in frequency domain, if there is interference, then the signal weight of carrying on the subcarrier being disturbed It is newly assigned to glitch-free subcarrier.

Refer to Fig. 2 step S1 is described in detail, concrete, obtain the step of optimum decision threshold value of signal such as Under:

S10: build the binary detection model of awgn channel and set initial decision threshold threshold value；Described initial decision threshold Threshold value is manually set, and its precision has to be determined, and the most described initial decision threshold is not necessarily the decision threshold of optimum；

S11: obtain false-alarm probability and detection probability based on described binary detection model and described initial decision threshold threshold value, When described false-alarm probability is the awgn channel free time, in awgn channel, the mean power of signal is more than the general of initial decision threshold threshold value Rate, described detection probability be awgn channel when there is CU in awgn channel the mean power of signal more than initial decision gate The probability of limit threshold value；

S12: obtain the compromise probability suppressing virtual probability to obtain while increasing detection probability, according to described compromise probability The mean power of the anti-signal pushed away is as optimum decision thresholding threshold value.

Further, the binary detection model of described awgn channel is:

$\left\{\begin{array}{c}{H}_0:r\left(t\right)=n\left(t\right)\\ H_1:r\left(t\right)=x\left(t\right)+n\left(t\right)\end{array}\right.$

Wherein, H₀Represent channel idle and there is no CU, H₁Representing that channel has CU, r (t) represents that channel connects The signal received, x (t) represents useful signal (i.e. deterministic signal), and n (t) represents noise signal.

Energy detector need not the priori of primary user's signal, it is only necessary to know that the white Gaussian noise power in background, Being received by band filter, calculate the energy receiving signal, whether the threshold value decision signal according to setting exists Interference.As can be seen here, the threshold value of setting directly affects the judgement precision of judgement structure.The present embodiment is believed based on AWGN The optimum decision thresholding threshold value that the binary detection model in road finally obtains needs to meet: at H₀In the moment, signal passes through energy measuring The mean power that device detection obtains is less than described optimum decision thresholding threshold value；At H₁In the moment, signal is detected by energy detector The mean power obtained is more than described optimum decision thresholding threshold value.

In the present embodiment, acquisition false-alarm probability employing equation below:

$P_F=P\{V_0>V_T^{\′}|H_0\}=p\{{\mathrm{\χ}}_{2TW}^2>V_T^{\′}\}---\left(1\right)$

Wherein, P_FRepresent false-alarm probability, V_T' represent initial decision threshold threshold value, H₀Represent channel idle and do not have CU, V₀The mean power of signal in awgn channel when representing the awgn channel free time,T table Showing the cycle, n (t) represents noise signal,H=2Wt-i,W represents bandwidth, n table Show the quantity of awgn channel.

Based on the analysis to formula (1), under the awgn channel be given, the expression formula of false-alarm probability is as follows:

$P_F=\frac{\mathrm{\Γ}(TW,\frac{V_T^{\′}}{2})}{\mathrm{\Γ}\left(TW\right)}---\left(2\right)$

Wherein, P_FExpression false-alarm probability, Γ (a, b) is incomplete gamma function, a=WT,V'_TRepresent initial Decision threshold threshold value, W represents that bandwidth, T represent the cycle.

In the present embodiment, acquisition detection probability employing equation below:

$P_D=P\{V_1>V_T^{\′}|H_1\}=p\{{\mathrm{\χ}}_{2TW}^2\left(\mathrm{\γ}\right)>V_T^{\′}\}---\left(3\right)$

Wherein, P_DRepresent detection probability, V_T' represent initial decision threshold threshold value, H₁Represent that channel has CU, V₁Table Show the mean power of signal when channel exists CU, N₀Represent signal Bilateral power spectral density, T represents the cycle, and x (t) represents useful signal,H=2Wt-i,X represents AWGN The quantity of channel.

Based on the analysis to formula (3), under awgn channel, the expression formula of detection probability is as follows:

$P_D=Q_{TW}(\sqrt{2\mathrm{\γ}},\sqrt{V_T^{\′}})---\left(4\right)$

Wherein, P_DRepresent detection probability, Q_u(a, b) is broad sense Marcum function, u=TW,W represents Bandwidth, V_TRepresenting initial decision threshold threshold value, T represents the cycle,X represents The quantity of awgn channel, N₀Represent the bilateral power spectral density of signal.

Understand, in false-alarm probability P based on formula (2) and formula (4) are analyzed_FTime identical, the detection probability that signal to noise ratio is big The biggest, namely losing probability is the least, illustrates that the signal to noise ratio size of sensing node is to detection performance important.When SNR not Become, along with false-alarm probability P_FIncrease, detection probability P_DAlso increase, but for cognitive user, it should increasing detection probability While suppress false-alarm probability.So needing to find a compromise between both, this compromise is for Energy-aware That is to say searching optimum decision threshold value.

The present invention consider on energy detector improve energy detecting efficiencies method while consider detection signal with Time by shade and the situation of multi-path fading effects, concentrate and the frequency spectrum perception with noise and interference be discussed, and from the angle of compromise Consider the coordination between multiple perception user CR (cognitive radio) and the relation between single CR perception complexity, due to noise Become with the uncertainty of interference and affect restriction important in primary user's robust detection, by closing on the coordination between CR node This uncertainty can be reduced, improve verification and measurement ratio.

It is also preferred that the left utilize frequency domain corresponding to signal that described optimum decision threshold value judgement TD-LTE system receiving terminal receives The judgement standard that whether there is interference on subcarrier is as follows:

If the average power signal of the signal that TD-LTE system receiving terminal receives is more than described optimum decision threshold value, then Whether interference is there is in subcarrier in frequency domain corresponding to signal that TD-LTE system receiving terminal receives；

If the average power signal of the signal that TD-LTE system receiving terminal receives is less than or equal to described optimum decision threshold value, It is to there is not interference in the subcarrier in frequency domain that then signal of TD-LTE system receiving terminal reception is corresponding.

Under interference environment, many interference signals are narrow band signal, disturb for this type of arrowband, it is possible to use TD-LTE institute Intrinsic frequency division characteristic, in conjunction with the result of frequency spectrum perception, redistributes glitch-free frequency spectrum resource, thus avoids doing when transmission The subcarrier frequency disturbed, improves reliability and the capacity of resisting disturbance of system of transmission.Concrete, TD-LTE system is first by whole Band resource is divided into some sub-bands.Then according to intensity and the bandwidth of interference signal, determine disturbed sub-band and can use Sub-band, then by the dispatching technique of subcarrier in frequency domain, distributes to usable subband each user, thus evades and being subject to The sub-band of interference.In other words,

Ruling out after in channel, whether signal exists interference based on optimum decision thresholding, by corresponding for the signal being disturbed Subcarrier is sent to transmitting terminal subcarrier controller by feedback channel, and by the modulated data zero setting on corresponding subcarrier, The subcarrier being disturbed is gone out again by ofdm signal frequency spectrum detection.The i.e. transmitting terminal in TD-LTE system receives feedback letter according to it What road was informed is disturbed subcarrier transmission ofdm signal, is mapped to the son load not being interfered after the signal that will send modulation On ripple, the subcarrier being disturbed the most does not distributes modulation symbol.

To sum up, in anti-interference method provided by the present invention, frequency based on the OFDM technology that TD-LTE system is used Intrinsic, first obtain the optimum decision threshold value of signal；Then, described optimum decision threshold value judgement TD-LTE system is utilized Whether interference is there is, if there is interference, the then subcarrier being disturbed in subcarrier in frequency domain corresponding to signal that receiving terminal receives The signal of upper carrying is reassigned to glitch-free subcarrier, i.e. redistributes glitch-free frequency spectrum resource, thus passes at signal Avoid interference time defeated, to improve the reliability of signal transmission, reach jamproof purpose.

Foregoing description is only the description to present pre-ferred embodiments, not any restriction to the scope of the invention, this Any change that the those of ordinary skill in bright field does according to the disclosure above content, modification, belong to the protection of claims Scope.

Claims (9)

1. an anti-interference method, it is characterised in that including:

Obtain the optimum decision threshold value of signal；

Utilize in subcarrier in frequency domain corresponding to signal that the receiving terminal of described optimum decision threshold value judgement TD-LTE system receives Whether existence is disturbed, if there is interference, then on the subcarrier being disturbed, the signal of carrying is reassigned to glitch-free sub-load Ripple.

2. anti-interference method as claimed in claim 1, it is characterised in that obtain the step of optimum decision threshold value of signal such as Under:

Build the binary detection model of awgn channel and set initial decision threshold threshold value；

False-alarm probability and detection probability, described false-alarm is obtained based on described binary detection model and described initial decision threshold threshold value When probability is the awgn channel free time, in awgn channel, the mean power of signal is more than the probability of initial decision threshold threshold value, described inspection Survey probability be awgn channel when there is CU in awgn channel the mean power of signal more than initial decision threshold threshold value Probability；

Obtain the compromise probability suppressing virtual probability to obtain while increasing detection probability, according to the anti-letter pushed away of described compromise probability Number mean power as optimum decision thresholding threshold value.

3. anti-interference method as claimed in claim 2, it is characterised in that the binary detection model of described awgn channel is:

$\left\{\begin{array}{c}{H}_0:r\left(t\right)=n\left(t\right)\\ H_1:r\left(t\right)=x\left(t\right)+n\left(t\right)\end{array}\right.$

Wherein, H₀Represent channel idle and there is no CU, H₁Representing that channel has CU, r (t) represents what channel received Signal, x (t) represents useful signal, and n (t) represents noise signal.

4. anti-interference method as claimed in claim 3, it is characterised in that acquisition false-alarm probability employing equation below:

$P_F=P\{V_0>V_T^{\′}|H_0\}=p\{{\mathrm{\χ}}_{2TW}^2>V_T^{\′}\}$

Wherein, P_FRepresent false-alarm probability, V '_TRepresent initial decision threshold threshold value, H₀Represent channel idle and there is no user Take, V₀The mean power of signal in awgn channel when representing the awgn channel free time,T represents the cycle, and n (t) represents Noise signal,H=2Wt-i,W represents that bandwidth, n represent the number of awgn channel Amount.

5. anti-interference method as claimed in claim 4, it is characterised in that under awgn channel, the expression formula of false-alarm probability is as follows:

$P_F=\frac{\mathrm{\Γ}(TW,\frac{V_T^{\′}}{2})}{\mathrm{\Γ}\left(TW\right)},$

Wherein, P_FExpression false-alarm probability, Γ (a, b) is incomplete gamma function, a=WT,V′_TRepresent initial decision gate Limit threshold value, W represents that bandwidth, T represent the cycle.

6. anti-interference method as claimed in claim 3, it is characterised in that acquisition detection probability employing equation below:

$P_D=P\{V_1>V_T^{\′}|H_1\}=p\{{\mathrm{\χ}}_{2TW}^2\left(\mathrm{\γ}\right)>V_T^{\′}\},$

Wherein, P_DRepresent detection probability, V '_TRepresent initial decision threshold threshold value, H₁Represent that channel has CU, V₁Represent channel The mean power of signal when there is CU, N₀Represent signal Bilateral power spectral density, T In the expression cycle, x (t) represents useful signal,H=2Wt-i,X represents that AWGN believes The quantity in road.

7. anti-interference method as claimed in claim 6, it is characterised in that under awgn channel, the expression formula of detection probability is as follows:

$P_D=Q_{TW}(\sqrt{2\mathrm{\γ}},\sqrt{V_T^{\′}}),$

Wherein, P_DRepresent detection probability, Q_u(a, b) is broad sense Marcum function,W represents band Width, V '_TRepresenting initial decision threshold threshold value, T represents the cycle,X represents The quantity of awgn channel, N₀Represent the bilateral power spectral density of signal.

8. anti-interference method as claimed in claim 1, it is characterised in that utilize described optimum decision threshold value to adjudicate TD-LTE The judgement standard that whether there is interference in subcarrier in frequency domain corresponding to signal that system receiving terminal receives is as follows:

If the average power signal of the signal that TD-LTE system receiving terminal receives is more than described optimum decision threshold value, then TD-LTE Whether interference is there is in subcarrier in frequency domain corresponding to signal that system receiving terminal receives；

If the average power signal of the signal that TD-LTE system receiving terminal receives is less than or equal to described optimum decision threshold value, then It is to there is not interference in subcarrier in frequency domain corresponding to signal that TD-LTE system receiving terminal receives.

9. anti-interference method as claimed in claim 1, it is characterised in that on the subcarrier that will be disturbed, the signal of carrying is again The process distributing to glitch-free subcarrier comprises the steps:

Do not give the subcarrier distribution modulation symbol being disturbed；

It is mapped on glitch-free subcarrier after signal modulation on the subcarrier that will be disturbed.