CN104052556B - Cooperation detection method used for radio-frequency spectrum sensing and based on diversity combination - Google Patents

Abstract

The invention discloses a cooperation detection method used for radio-frequency spectrum sensing and based on diversity combination. According to the cooperation detection method used for radio-frequency spectrum sensing and based on diversity combination, the frequency spectrum usage condition of a main user is detected by each sensing user in a radio system, one sensing user is selected to serve as an information fusion center, maximal-ratio combination of information, obtained through detection, of the sensing users is conducted through the information fusion center, signal energy existing after combination is obtained, a judgment is made by the information fusion center according to the signal energy of a signal obtained after combination, a main user signal exists if the signal energy of the signal obtained after combination is larger than a judgment threshold, and no main user signal exists if the signal energy of the signal obtained after combination is not larger than the judgment threshold. The radio-frequency spectrum sensing type cooperation detection method based on diversity combination, the judgment sensitivity is high, detection is accurate, and the frequency spectrum sensing performance is greatly improved.

Description

A kind of cooperative detection method of the radio spectrum sensing based on diversity merging

Technical field

The present invention relates to cognitive radio system, it is particularly well-suited to the perception multi-user Cooperation inspection of radio system intermediate frequency spectrum Survey.

Background technology

The detection method of existing radio spectrum sensing is Single-user detection although the principle of Single-user detection is simple Single it is not necessary to the detection time between coordinates user and detection consume, but these detection methods in actual application scenarios not Higher detection performance can be reached, Single-user detection has concealed terminal and the deficiency of two aspects of shadow effect.

Content of the invention

Present invention aims to cooperative detection sensitivity is low in frequency spectrum perception, the high problem of complexity it is proposed that A kind of cooperative detection method of the radio spectrum sensing based on diversity merging.Inventive algorithm complexity is relatively low, accuracy of detection Height, improves the effect of frequency spectrum perception, is that making full use of of cognitive radio intermediate frequency spectrum resource lays the foundation.

The object of the present invention is achieved like this：

A kind of cooperative detection method of the radio spectrum sensing based on diversity merging, includes primary in radio system Family and perception user, wherein primary user use user for spectrum authorization, and perception user is that application frequency spectrum uses user, including following Step：

(1) the perception user that in radio system, each participates in cooperative detection enters to the frequency spectrum service condition of primary user respectively Row detection, obtains respective detection information；

(2) select a perception user from radio system as information fusion center, by remaining perception user's detection To detection information be respectively transmitted to information fusion center；

(3) detection information that itself is detected by information fusion center and the detection information that remaining perception user detects are entered Row maximum-ratio combing, obtains a merging signal；

(4) information fusion center carries out simple gate limit energy measuring by merging signal：First N point is carried out to merging signal quick Fourier transformation, is converted to frequency-region signal by merging signal, and information fusion center, to frequency-region signal modulus square, obtains frequency domain letter Number signal energy, the signal energy of frequency-region signal is the signal energy merging signal, and wherein, N is the natural number more than 1； Prescribe a time limit when the energy value merging signal is more than the simple gate setting, then the frequency spectrum of explanation primary user is in use state；Believe when merging Number energy value be less than set simple gate prescribe a time limit, then explanation primary user frequency spectrum be in idle condition；

Complete the cooperative detection of the radio spectrum sensing based on diversity merging.

Wherein, the detection signal that each the perception user described in step (1) detects is expressed as s_n(t)=h_nx(t)+n_n T (), wherein n are the natural number more than 1, the envelope signal of subscriber signal, h based on x (t)_nLetter for n-th perception user's detection Road gain, n_nAdditive white noise for n-th perception user's detection.

Wherein, merging signal s (t) described in step (3) is expressed as:

Whereinα_nRepresent the signal amplitude of the detection signal of n-th perception user, N₀/ 2 is that perception user connects The noise power of the detection signal receiving, the detection signal that each perception user detects can be expressed as s_n(t)=h_nx(t)+ n_nT (), wherein n are the natural number more than 1, the envelope signal of subscriber signal, h based on x (t)_nFor n-th perception user's detection Channel gain, n_nT () is the additive white noise of n-th perception user detection.

The present invention compared with prior art has the advantages that：

(1) inventive algorithm complexity is relatively low, and accuracy of detection is high, improves the effect of frequency spectrum perception.

(2) lift the accuracy of detection of frequency spectrum perception by this algorithm, improve the utilization rate of frequency spectrum resource, rational distribution is recognized Know the frequency spectrum of user.

Brief description：

Fig. 1 is the phantom of cooperative detection of the present invention；

Fig. 2 is the system block diagram of cooperative detection of the present invention；

Fig. 3 is cooperative detection of the present invention and other detection method Performance comparision schematic diagrams under Gaussian channel；

Fig. 4 is the Performance comparision schematic diagram of cooperative detection of the present invention and other detection methods under Rayleigh channel.

Specific embodiment：

Below, in conjunction with accompanying drawing, the invention will be further described.

The present invention relates to a kind of cooperative detection method of the radio spectrum sensing based on diversity merging, in radio system Include primary user and perceive user, wherein primary user uses user for spectrum authorization, perception user is application frequency spectrum using use Family, comprises the following steps：

(1) the perception user that in radio system, each participates in cooperative detection enters to the frequency spectrum service condition of primary user respectively Row detection, obtains respective detection information；

Wherein, the detection signal that each the perception user described in step (1) detects can be expressed as s_n(t)=h_nx (t)+n_nT (), wherein n are the natural number more than 1, the envelope signal of subscriber signal, h based on x (t)_nFor n-th perception user's inspection The channel gain surveyed, n_nAdditive white noise for n-th perception user's detection.

As depicted in figs. 1 and 2, in existing frequency spectrum perception technical research, being all phase is supposed to the detection environment of detection user With it is therefore an objective to the detection performance of parser in theory, embody the superior of cooperation.But in actual collaboration frequency spectrum detection Middle extraneous environment is all change, detecting distance, and the impact of channel gain makes each perceive the testing result of user not to the utmost Identical, and the performance of cooperative detection is carried out studying more meaningful under physical condition.

In figure participates in n perception user of cooperative detection, is respectively defined as SU_n(n=1,2,3 ...), a primary user, It is defined as PU；Each environment residing for perception user is different, and channel gain is set to h_n(n=1,2,3 ...), and each detection use The signal to noise ratio that accepts at family is incremented by with constant Δ dB, so in order to close to actual communication part and external environment.Additionally, individually One perception user (SU_n) as information processing fusion center, at the detection data of other N-1 perception users Reason, obtains final testing result.

(2) select a perception user from radio system as information fusion center, by remaining perception user's detection To detection information be respectively transmitted to information fusion center；

(3) detection information that itself is detected by information fusion center and the detection information that remaining perception user detects are entered Row maximum-ratio combing, obtains a merging signal；

Wherein, merging signal s (t) described in step (3) is expressed as:

Whereinα_nRepresent the signal amplitude of the detection signal of n-th perception user, N₀/ 2 is that perception user connects The noise power of the detection signal receiving.

(4) information fusion center carries out simple gate limit energy measuring by merging signal：First N point is carried out to merging signal quick Fourier transformation, is converted to frequency-region signal by merging signal, and information fusion center, to frequency-region signal modulus square, obtains frequency domain letter Number signal energy, the signal energy of frequency-region signal is the signal energy merging signal, and wherein, N is the natural number more than 1； Prescribe a time limit when the energy value merging signal is more than the simple gate setting, then the frequency spectrum of explanation primary user is in use state；Believe when merging Number energy value be less than set simple gate prescribe a time limit, then explanation primary user frequency spectrum be in idle condition.

Fig. 3 and Fig. 4 is beneficial effects of the present invention.

Wherein, Fig. 3 be Gaussian channel under maximum-ratio combing, equal gain combining, multi-threshold cooperation, " OR " rule and " AND " The detection probability analogous diagram of the different cooperation mode of this five kinds of rule.- 10<SNR<In the range of -2 dB, overall detection probability is all Ratio is relatively low, and the testing result of maximum-ratio combing is slightly below equal gain combining.But in SNR>Merged based on diversity after -2dB The detection performance of cooperative detection method is substantially better than simple gate and limits multi-user Cooperation mode, and maximum-ratio combing technology is will be all of Signal message judges after merging again, and therefore detection probability highest has just reached 1 substantially in 5 dB moment.

Fig. 4 gives maximum-ratio combing under Rayleigh fading channel, equal gain combining, multi-threshold detection and simple gate limit " OR " merges the analogous diagram of these four cooperative detection modes, because the influence of fading of signal energy makes the detection probability of system whole Body declines, and detection performance reduces, but the accuracy of detection of the maximum-ratio combing cooperative detection method being merged based on diversity is still High.

Claims (1)

1. a kind of cooperative detection method of the radio spectrum sensing based on diversity merging, includes primary user in radio system With perception user, wherein primary user is that spectrum authorization uses user, perception user be application frequency spectrum using user it is characterised in that Comprise the following steps：

(1) the perception user that in radio system, each participates in cooperative detection examines to the frequency spectrum service condition of primary user respectively Survey, obtain respective detection information；

(2) select a perception user from radio system as information fusion center, remaining perception user is detected Detection information is respectively transmitted to information fusion center；

(3) detection information that itself is detected by information fusion center and the detection information that remaining perception user detects are carried out Big ratio merges, and obtains a merging signal；

Described merging signal s (t) is expressed as:

$s\left(t\right)=\underset{n=1}{\overset{N}{\&Sigma;}}{a}_n{s}_n\left(t\right)=\underset{n=1}{\overset{N}{\&Sigma;}}{a}_n{h}_{n}x\left(t\right)+\underset{n=1}{\overset{N}{\&Sigma;}}{a}_n{n}_n\left(t\right)$

Wherein,α_nRepresent the signal amplitude of the detection signal of n-th perception user, N₀/ 2 is that perception user receives The noise power of the detection signal arriving, the detection signal that each perception user detects is expressed as s_n(t)=h_nx(t)+n_n(t), Wherein n is the natural number more than 1, the envelope signal of subscriber signal, h based on x (t)_nChannel for n-th perception user's detection increases Benefit, n_nT () is the additive white noise of n-th perception user detection；

(4) information fusion center carries out simple gate limit energy measuring by merging signal：First merging signal is carried out in quick Fu of N point Leaf transformation, is converted to frequency-region signal by merging signal, information fusion center, to frequency-region signal modulus square, obtains frequency-region signal Signal energy, the signal energy of frequency-region signal is the signal energy merging signal, and wherein, N is the natural number more than 1；Work as conjunction And the energy value of signal is more than the simple gate setting and prescribes a time limit, then the frequency spectrum of explanation primary user is in use state；When merging signal Energy value is less than the simple gate setting and prescribes a time limit, then the frequency spectrum of explanation primary user is in idle condition；

Complete the cooperative detection of the radio spectrum sensing based on diversity merging.