CN106131824A - Cordless communication network allied signal feedback and man made noise's safety of physical layer communication means - Google Patents

Abstract

The invention discloses a kind of cordless communication network allied signal feedback and man made noise's safety of physical layer communication means, including: the first stage, the information of need for confidentiality is issued legitimate receipt end by transmitting terminal.Second stage, after legitimate receipt end receives information, mixes a certain amount of man made noise in the information received, and mixed signal is fed back to transmitting terminal.Phase III, the signal fed back is sent to receiving terminal by transmitting terminal, legitimate receipt end is due to the man made noise of known second stage, so man made noise can be eliminated by it, and eavesdrop end and can not be eliminated, thus performance can be cut down by man made noise, thus realize the secure communication between transmitting terminal and receiving terminal.Not having antenna advantage on the most legal communication equipment, do not have outside aid, do not eavesdrop any channel information of end, just can ensure the secure communication between legitimate device, the present invention possesses superiority in terms of communication security.

Description

Cordless communication network allied signal feedback and man made noise's safety of physical layer communication means

Technical field

The invention belongs to wireless communication field, relate to safe transmission scheme, be specifically related in cordless communication network combine letter Number feedback with man made noise design safety of physical layer communication plan.

Background technology

Due to the broadcast characteristic of radio communication, the communication between equipment and equipment is easy to be eavesdropped end eavesdropping.Although, pass The safety of physical layer scheme of system can promote the safety of communication to a certain extent effectively, but it still exists some and lacks Point.Such as, one, the known transient channel information eavesdropping end of transmitting terminal or statistic channel information.But it is it practice, complete for one For the most passive earwig's (i.e. earwig does not send any information, only receives information), validated user is difficult to obtain its channel Information.Two, transmitting terminal or legitimate receipt end need ratio to eavesdrop end more antenna.In reality, on the one hand transmitting terminal or connect Receiving end is likely to be due to the reason of size and cost can not configure multiple antenna, and on the other hand, the advantage on antenna amount is obvious It is inequitable for eavesdropping end, because it can use more antenna.Three, transmitting terminal and legitimate receipt end need outside The help of cooperative node (such as, relaying).In reality, it is likely that there is not the aid of outside, perhaps this aid itself Being exactly insecure, it may decode the information of validated user.

Summary of the invention

In order to solve problem potential in above-mentioned existing program, the present invention proposes a kind of new safety of physical layer scheme Realize the communication security between equipment.

The present invention is realized by following technical proposals.

The cordless communication network allied signal feedback provided according to embodiments of the present invention is led to man made noise's safety of physical layer Letter method, comprises the steps:

First stage, transmitting terminal uses channel inversion technique, mixes with variance be in information s of need for confidentiality's Man made noise w₁, send first stage signal x_a1, it is ensured that send signal and meet first stage Power LimitationLegitimate receipt Termination receives first stage informationAnd receive first stage Signal to Interference plus Noise Ratio accordinglyEavesdrop termination receive include need Information s to be maintained secrecy with mixing with variance isMan made noise w₁InformationEavesdrop end and receive corresponding first rank Section receives Signal to Interference plus Noise Ratio

Second stage, legitimate receipt end is also adopted by channel inversion technique, to transmitting terminal feedback signal x_b, this feedback signal It is to terminate, based on legitimate receipt, the first stage information receivedInformation s of need for confidentiality, melange belt is included in feedback signal The variance is had to beMan made noise w₁, and mix and a certain amount of with variance beGauss man made noise w₂, it is ensured that feedback Signal meets second stage Power LimitationAnd mixed signal is fed back to transmitting terminal；Transmitting terminal receives second Stage feedback signal y_a, transmitting terminal can be with variance beingMan made noise w₁Disappear；Eavesdrop end to receive in second stage Signal y_e2, eavesdrop end can not with man made noise w₁Disappear；Eavesdrop termination to receive corresponding second stage to receive letter dry Make an uproar and compare γ_e2；

Phase III, transmitting terminal still uses channel inversion technique, is sent in feedback signal and includes the letter of need for confidentiality Cease s, with variance beGauss man made noise w₂, and be contaminated with variance and beGauss man made noise w₃Signal Ensure that sending signal meets Power LimitationLegitimate receipt end receives second stage signalReceiving terminal can be w₂Disappear Fall；Legitimate receipt termination receives corresponding second stage and receives Signal to Interference plus Noise RatioEavesdrop the reception phase III signal of endEavesdropping end can not be w₂Disappear, w₂Sufficiently large infringement is caused to eavesdropping end；Eavesdrop termination corresponding phase III reception letter Dry making an uproar compares γ_e3；

By introducing extra first stage variance it isGauss man made noise w₁, second stage variance beHeight This man made noise w₂With phase III variance it isGauss man made noise w₃, and ensure that second stage feedback signal meets simultaneously Second stage Power LimitationAnd first stage and phase III send signal and meet first stage Power LimitationAnd to makeAnd then shouldPower Limitation should be all higher than the merit set Rate threshold value p₀So thatWithLess than Power Limitation Less than Power LimitationThus realize transmitting terminal and Secure communication between receiving terminal.

Further, in the described first stage, channel coefficients is worked as | h_AB|²More than interrupt threshold γ₀Time, transmitting terminal uses channel Inversion technique sends signal: x_a1=(s+w₁)/h_AB。

Further, the Power Limitation of transmitting terminalS and w₁Variance must be fulfilled for

Further, in the first stage, legitimate receipt termination receives first stage information:

$y_{b_1}=h_{AB}{x}_{a1}+n_{b1}=h_{AB}\·\frac{1}{h_{AB}}(s+w_1)+n_{b1}=s+w_1+n_{b1}$

Eavesdrop termination and receive the information of first stage:

$y_{e_1}=h_{AE}{x}_{a1}+n_{e1}=h_{AE}\·\frac{1}{h_{AB}}(s+w_1)+n_{e1}=\frac{h_{AE}}{h_{AB}}s+\frac{h_{AE}}{h_{AB}}{w}_1+n_{e1}.$

Further, in second stage, meet condition at channel coefficients | h_BA|²>γ₀Time, to transmitting terminal feedback signal:

$x_b=\mathrm{\α}\·(y_{b_1}+w_2)/h_{BA}.$

Further, in second stage, transmitting terminal is connected on the feedback signal that second stage receives and is

$y_a=\mathrm{\α}(s+w_1+w_2+n_{b_1})+n_a$

Transmitting terminal can be w₁Disappearing, disappear w₁After reception signal be

${\tilde{y}}_a=\mathrm{\α}s+\mathrm{\α}(w_2+n_{b_1})+n_a$

But, eavesdrop the signal y that end receives in second stage_e2, eavesdrop end can not with man made noise w₁Disappear；Steal Listen the signal y that end receives_e2For

$y_{e2}=\mathrm{\α}\frac{h_{BE}}{h_{BA}}s+\mathrm{\α}\frac{h_{BE}}{h_{BA}}(w_1+n_{b_1}+w_2)+n_{e_2}.$

Further, in the phase III, when channel coefficients meets | h_AB|²>γ₀Time, transmission signal:

$x_{a_2}=\mathrm{\β}({\tilde{y}}_a+w_3)/h_{AB}.$

In phase III, legitimate receipt end receives the signal of second stage and is

$y_{b_2}=\mathrm{\β}\mathrm{\α}s+\mathrm{\β}\mathrm{\α}(w_2+n_{b_1})+\mathrm{\β}(n_a+w_3)+n_{b_2}.$

Receiving terminal receives signal and becomes

${\tilde{y}}_{b2}=\mathrm{\β}\mathrm{\α}s+{\mathrm{\β\αn}}_{b_1}+\mathrm{\β}(n_a+w_3)+n_{b_2}.$

Now, the reception phase III signal eavesdropping end is

$y_{e_3}=\frac{h_{AE,2}}{h_{AB}}\mathrm{\β}\mathrm{\α}s+\frac{h_{AE,2}}{h_{AB}}\left(\mathrm{\β}\mathrm{\α}\right(w_2+n_{b_1})+\mathrm{\β}(n_a+w_3\left)\right)+n_{e_3}.$

Further, the legitimate receipt end in first and third stage receives Signal to Interference plus Noise Ratio accordingly and is

${\mathrm{\γ}}_{b_1}=\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2+{\mathrm{\σ}}_b^2},{\mathrm{\γ}}_{b_2}=\frac{{\mathrm{\β}}^2{\mathrm{\α}}^2{\mathrm{\σ}}_s^2}{{\mathrm{\β}}^2{\mathrm{\α}}^2{\mathrm{\σ}}_b^2+{\mathrm{\β}}^2({\mathrm{\σ}}_a^2+{\mathrm{\σ}}_{w_3}^2)+{\mathrm{\σ}}_b^2}$

The white Gaussian noise of end is eavesdropped in first, second and third stageTime, eavesdropping end received signal to noise ratio is

${\mathrm{\γ}}_{e_1}=\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2},{\mathrm{\γ}}_{e_2}=\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2+{\mathrm{\σ}}_{w_2}^2+{\mathrm{\σ}}_b^2},{\mathrm{\γ}}_{e_3}=\frac{{\mathrm{\α}}^2{\mathrm{\σ}}_s^2}{{\mathrm{\α}}^2({\mathrm{\σ}}_{w_2}^2+{\mathrm{\σ}}_b^2)+{\mathrm{\σ}}_a^2+{\mathrm{\σ}}_{w_3}^2}.$

The present invention has a following useful technique effect:

By introducing extra first stage Gauss man made noise w₁, second stage Gauss man made noise w₂And the phase III Gauss man made noise w₃, and ensure that second stage feedback signal meets Power Limitation and first stage and phase III simultaneously Send signal and meet Power Limitation, and the Signal to Interference plus Noise Ratio that receives of legitimate receipt end to be made is more than the Signal to Interference plus Noise Ratio eavesdropping end, i.e.And then first, second and third stage power limit should be all higher than set power threshold p₀So that the One, two, triphasic man made noise's variance is respectively less than Power Limitation, thus realizes the safety between transmitting terminal and receiving terminal and lead to Letter.

In the solution of the present invention, legal communication equipment does not has the advantage on antenna, and (the most all of user is the most single Antenna), there is no outside aid, any channel information not eavesdropping end (includes eavesdropping the additive white Gaussian noise water of end Flat), but still can realize secure communication, the present invention possesses superiority in terms of communication security.

Accompanying drawing explanation

Fig. 1 is the system model figure of the present invention；

Fig. 2 is that safe capacity is with the variation diagram of general power ratio shared by noise power；

Fig. 3 is the safe capacity variation diagram with transmit power；

Fig. 4 is the safe capacity variation diagram with interrupt threshold.

Detailed description of the invention

The invention will be described in further detail with embodiment below in conjunction with the accompanying drawings, but is not intended as doing invention any limit The foundation of system.

Cordless communication network allied signal of the present invention feedback and man made noise's safety of physical layer communication means, first provide this The system model of invention, shown in illustraton of model as accompanying drawing 1:

There is three nodes, a transmitting terminal in system, a legitimate receipt end and one eavesdrop end.All of equipment is all Only single antenna.Eavesdrop end and be able to receive that transmitting terminal issues the signal of legitimate receipt end, also can receive legitimate receipt end Feed back to the signal of transmitting terminal.From transmitting terminal to legitimate receipt end, from legitimate receipt end to transmitting terminal, from transmitting terminal to eavesdropping End, is respectively h from legitimate receipt end to the channel eavesdropping end_AB, h_BA, h_AEAnd h_BE.Wherein, h_ABAnd h_BAIt it is 0 average unit variance The multiple Gaussian channel of Cyclic Symmetry, and experience quasistatic decline, i.e. within a period of time, channel keeps constant.Transmitting terminal and conjunction The through-put power of method receiving terminal is respectively less than P_aAnd P_b.All additive white Gaussian noises of transmitting terminal and legitimate receipt end are all returned One turns to 0 average and unit variance.Transmitting terminal, legitimate receipt end and eavesdrop end and both know about h_ABAnd h_BAAccurate information.Eavesdrop End knows oneself channel (i.e. h_AEAnd h_BE) accurate information.But, transmitting terminal, legitimate receipt end all do not know h_AE、h_BEAnd steal Listen the additive white Gaussian noise of endAny information.

Cordless communication network allied signal feedback is as follows with the safety of physical layer communication means step of man made noise:

First stage: transmitting terminal uses channel inversion technique, works as channel coefficients | h_AB|²More than interrupt threshold γ₀(i.e. | h_AB |²>γ₀) time, mix in information s of need for confidentiality and with variance beMan made noise w₁, send first stage signal x_a1, Transmission signal is x_a1=(s+w₁)/h_AB。

Wherein, s is the information of need for confidentiality, w₁Being the Gauss man made noise mixed the first stage, its average is 0, side Difference ish_ABIt is the transmitting terminal channel to receiving terminal, the present invention is normalized to obey the circulation of 0 average unit variance Symmetric complex channel.Power Limitation due to transmitting terminalS and w₁Variance must be fulfilled for

Wherein,For the variance of the information of need for confidentiality, P_aThe transmit power instantaneous for transmitting terminal limits,And it appeared that the average power limit of this entiretyIt is and interrupt threshold γ₀There are close ties 's.Additionally,

For asking for 1/ | h_AB|²Meansigma methods, wherein, p (x) is channel coefficients | h_AB|²'s Probability density function, and obey the exponential that parameter is 1, i.e.

P (x)=e^-x。

Legitimate receipt termination receives the information of first stage and is

$y_{b_1}=h_{AB}{x}_{a1}+n_{b1}=h_{AB}\·\frac{1}{h_{AB}}(s+w_1)+n_{b1}=s+w_1+n_{b1},---\left(3\right)$

Wherein,Being the legitimate receipt end additive white Gaussian noise in the first stage, average is 0, and variance isMeanwhile, Legitimate receipt end receives Signal to Interference plus Noise Ratio accordingly

Eavesdropping the first stage information that receives of termination is

$y_{e_1}=h_{AE}{x}_{a1}+n_{e1}=h_{AE}\·\frac{1}{h_{AB}}(s+w_1)+n_{e1}=\frac{h_{AE}}{h_{AB}}s+\frac{h_{AE}}{h_{AB}}{w}_1+n_{e1},---\left(4\right)$

Wherein, h_AEIt is transmitting terminal to eavesdropping the channel of end, n_e1It is to eavesdrop to hold the additive white Gaussian noise in the first stage, Average is 0, and variance is

Meanwhile, termination corresponding reception Signal to Interference plus Noise Ratio γ is eavesdropped_e1。

Second stage: legitimate receipt end is also adopted by channel inversion technique, and meets condition at channel coefficients | h_BA|²>γ₀ Time, feedback signalThis feedback signal is the connecing of first stage received based on legitimate receipt termination The collection of letters numberIncluding need for confidentiality information s, mix and with variance beMan made noise w₁, and mix a certain amount of side Difference isGauss man made noise w₂, w₂Be its average of Gauss man made noise being mingled in feedback signal be 0.α be in order to Ensure that feedback signal meets Power LimitationThen there is following formula,

Wherein, P_bThe transmit power instantaneous for transmitting terminal limits,Limit for sending signal power,Additionally,

For asking for 1/ | h_BA|²Meansigma methods, wherein q (x) is channel coefficients | h_BA|²'s Probability density function.Q (x) is channel coefficients | h_BA|²Probability density function, and obey the exponential that parameter is 1, i.e. q (x)=e^-x.Thus it is possible to obtain the expression formula of α,

Therefore, transmitting terminal is connected on the feedback signal that second stage receives and is

$y_a=\mathrm{\α}(s+w_1+w_2+n_{b_1})+n_a---\left(8\right)$

Wherein, n_aBeing the additive white Gaussian noise of transmitting terminal, average is 0, and variance isBecause w₁It is that transmitting terminal oneself exists The man made noise that first stage sends, it is to know w₁Exact value.Meanwhile, the value of α is disclosed, i.e. system all devices (including eavesdropping end) both knows about the occurrence of α.So in second stage, transmitting terminal can be w₁Disappear.Then, disappear w₁After Reception signal is

${\tilde{y}}_a=\mathrm{\α}s+\mathrm{\α}(w_2+n_{b_1})+n_a.---\left(9\right)$

Eavesdrop and hold the signal received in second stage to be

$y_{e2}=\mathrm{\α}\frac{h_{BE}}{h_{BA}}s+\mathrm{\α}\frac{h_{BE}}{h_{BA}}(w_1+n_{b_1}+w_2)+n_{e_2},---\left(10\right)$

Wherein,Being to eavesdrop to hold the additive white Gaussian noise in second stage, average is 0, and variance isNotice w₁It is Eavesdrop end the unknown.Can not be w so eavesdropping end₁Disappear, thus its reception signal can be by w₁Infringement.Meanwhile, termination is eavesdropped Corresponding reception Signal to Interference plus Noise Ratio γ_e2。

Consider that channel is quasi-static, i.e. phase III and first stage h_ABKeep constant.Then, transmitting terminal is on the 3rd rank Duan Yiran uses channel inversion technique, when channel coefficients meets | h_AB|²>γ₀Time, send signal w₃Being the Gauss man made noise being mingled in feedback signal, its average is 0, and variance is For the w that disappears₁After reception letter Number, β is to ensure that transmission signal meets Power LimitationIt must is fulfilled for

Therefore, β can be expressed as

Then, the second stage signal that phase III legitimate receipt end receives is

$y_{b_2}=\mathrm{\β}\mathrm{\α}s+\mathrm{\β}\mathrm{\α}(w_2+n_{b_1})+\mathrm{\β}(n_a+w_3)+n_{b_2},---\left(13\right)$

Wherein,Being the legitimate receipt end additive white Gaussian noise in the phase III, average is 0, and variance isDue to w₂ Being that receiving terminal feeds back to the signal of transmitting terminal in second stage, it is that receiving end is known.Meanwhile, it is open due to β again , i.e. all devices (including eavesdropping end) both knows about its exact value.So in the phase III, receiving terminal can be w₂Disappear, its Reception signal becomes

${\tilde{y}}_{b2}=\mathrm{\β}\mathrm{\α}s+{\mathrm{\β\αn}}_{b_1}+\mathrm{\β}(n_a+w_3)+n_{b_2}.---\left(14\right)$

Meanwhile, legitimate receipt end receives Signal to Interference plus Noise Ratio accordingly

Now, the reception signal eavesdropping end is

$y_{e_3}=\frac{h_{AE,2}}{h_{AB}}\mathrm{\β}\mathrm{\α}s+\frac{h_{AE,2}}{h_{AB}}\left(\mathrm{\β}\mathrm{\α}\right(w_2+n_{b_1})+\mathrm{\β}(n_a+w_3\left)\right)+n_{e_3},---\left(15\right)$

Wherein,Being to eavesdrop to hold the additive white Gaussian noise in the phase III, average is 0, and variance ish_AE,2It is to eavesdrop Hold the channel in the phase III, due to, transmitting terminal is not aware that the channel information eavesdropping end, so h here_AE,2With the first rank The h of section_AEThe most identical.W is not known owing to eavesdropping end₂Value, this stage it can not be w₂Disappear, thus can be by w₂ Infringement.Meanwhile, termination corresponding reception Signal to Interference plus Noise Ratio γ is eavesdropped_e3。

The man made noise w feedbacked in second stage just because of legitimate receipt end₂Can by it certainly in the phase III Oneself disappears, but but can not be eavesdropped end and disappear so that the present invention can design suitable w₂Cause sufficiently large to eavesdropping end Infringement, thus realize secure communication.Concrete w₂Design is by meeting following formulaEmbody 's.

Legitimate receipt end can be obtained according to formula (3) and (14) and receive Signal to Interference plus Noise Ratio accordingly be

${\mathrm{\γ}}_{b_1}=\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2+{\mathrm{\σ}}_b^2},{\mathrm{\γ}}_{b_2}=\frac{{\mathrm{\β}}^2{\mathrm{\α}}^2{\mathrm{\σ}}_s^2}{{\mathrm{\β}}^2{\mathrm{\α}}^2{\mathrm{\σ}}_b^2+{\mathrm{\β}}^2({\mathrm{\σ}}_a^2+{\mathrm{\σ}}_{w_3}^2)+{\mathrm{\σ}}_b^2}.---\left(16\right)$

Similarly, can obtain eavesdropping the received signal to noise ratio of end according to formula (4), (10) and (15) is

$\begin{array}{c}{\mathrm{\γ}}_{e_1}=\frac{\frac{{\left|h_{AE}\right|}^2}{{\left|h_{AB}\right|}^2}{\mathrm{\σ}}_s^2}{\frac{{\left|h_{AE}\right|}^2}{{\left|h_{AB}\right|}^2}{\mathrm{\σ}}_{w_1}^2+{\mathrm{\σ}}_e^2},\\ {\mathrm{\γ}}_{e_2}=\frac{{\mathrm{\α}}^2\frac{{\left|h_{BE}\right|}^2}{{\left|h_{BA}\right|}^2}{\mathrm{\σ}}_s^2}{{\mathrm{\α}}^2\frac{{\left|h_{BE}\right|}^2}{{\left|h_{BA}\right|}^2}({\mathrm{\σ}}_{w_1}^2+{\mathrm{\σ}}_{w_2}^2+{\mathrm{\σ}}_b^2)+{\mathrm{\σ}}_e^2},\\ {\mathrm{\γ}}_{e_3}=\frac{{\mathrm{\β}}^2{\mathrm{\α}}^2\frac{{\left|h_{AE,2}\right|}^2}{{\left|h_{AB}\right|}^2}{\mathrm{\σ}}_s^2}{{\mathrm{\β}}^2{\mathrm{\α}}^2\frac{{\left|h_{AE,2}\right|}^2}{{\left|h_{AB}\right|}^2}({\mathrm{\σ}}_{w_2}^2+{\mathrm{\σ}}_b^2)+\frac{{\left|h_{AE,2}\right|}^2}{{\left|h_{AB}\right|}^2}{\mathrm{\β}}^2({\mathrm{\σ}}_a^2+{\mathrm{\σ}}_{w_3}^2)+{\mathrm{\σ}}_e^2}.\end{array}---\left(17\right)$

The channel information of end is eavesdropped, including the white Gaussian noise eavesdropping end owing to transmitting terminal is not aware thatBeing how many is also Ignorant.So, the present invention considers a kind of for validated user during worst, i.e.Then, eavesdrop The reception Signal to Interference plus Noise Ratio of end can be expressed as

${\mathrm{\γ}}_{e_1}=\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2},{\mathrm{\γ}}_{e_2}=\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2+{\mathrm{\σ}}_{w_2}^2+{\mathrm{\σ}}_b^2},{\mathrm{\γ}}_{e_3}=\frac{{\mathrm{\α}}^2{\mathrm{\σ}}_s^2}{{\mathrm{\α}}^2({\mathrm{\σ}}_{w_2}^2+{\mathrm{\σ}}_b^2)+{\mathrm{\σ}}_a^2+{\mathrm{\σ}}_{w_3}^2}.---\left(18\right)$

Assume legitimate receipt end and all use maximum-ratio combing receiver with eavesdropping to hold, then legitimate receipt end and the appearance eavesdropping end Amount is respectively

$\begin{array}{c}{C}_b({\mathrm{\γ}}_0,{\mathrm{\σ}}_{w_1}^2,{\mathrm{\σ}}_{w_2}^2)=\frac{1}{3}\·P_{no\_out}\·log(1+{\mathrm{\γ}}_{b_1}+{\mathrm{\γ}}_{b_2})\\ =\frac{1}{3}\·e^{-2{\mathrm{\γ}}_0}\·\log (1+\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2+{\mathrm{\σ}}_b^2}+\frac{{\mathrm{\β}}^2{\mathrm{\α}}^2{\mathrm{\σ}}_s^2}{{\mathrm{\β}}^2{\mathrm{\α}}^2{\mathrm{\σ}}_b^2+{\mathrm{\β}}^2{\mathrm{\σ}}_a^2+{\mathrm{\σ}}_b^2})\end{array},---\left(19\right)$

And

$\begin{array}{c}{C}_e({\mathrm{\γ}}_0,{\mathrm{\σ}}_{w_1}^2,{\mathrm{\σ}}_{w_2}^2)=\frac{1}{3}\·P_{no\_out}\·log(1+{\mathrm{\γ}}_{e_1}+{\mathrm{\γ}}_{e_2}+{\mathrm{\γ}}_{e_3})\\ =\frac{1}{3}\·e^{-2{\mathrm{\γ}}_0}\·\log (1+\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2}+\frac{{\mathrm{\σ}}_s^2}{{\mathrm{\σ}}_{w_1}^2+{\mathrm{\σ}}_{w_2}^2+{\mathrm{\σ}}_b^2}+\frac{{\mathrm{\α}}^2{\mathrm{\σ}}_s^2}{{\mathrm{\α}}^2({\mathrm{\σ}}_{w_2}^2+{\mathrm{\σ}}_b^2)+{\mathrm{\σ}}_a^2})\end{array},---\left(20\right)$

Wherein, P_{no_out}Referring to the probability not occurring to interrupt when using channel inversion technique in three phases, it is concrete Can be expressed asHere only have not interrupting generally of the first two-stage Rate is multiplied, and to be because the channel of phase III and first stage be the same, as long as the first stage can transmit signal, then the 3rd rank Duan Yiding can transmit.

Thus it is possible to obtain at some fixing interrupt threshold γ₀Under, the safe capacity of system is

$\begin{array}{c}{C}_s({\mathrm{\γ}}_0,{\mathrm{\σ}}_{w_1}^2,{\mathrm{\σ}}_{w_2}^2)={\[C_b({\mathrm{\γ}}_0,{\mathrm{\σ}}_{w_1}^2,{\mathrm{\σ}}_{w_2}^2)-C_e({\mathrm{\γ}}_0,{\mathrm{\σ}}_{w_1}^2,{\mathrm{\σ}}_{w_2}^2)\]}^{+}\\ =\frac{1}{3}\·e^{-2{\mathrm{\γ}}_0}\·{\[\log (1+{\mathrm{\γ}}_{b_1}+{\mathrm{\γ}}_{b_2})-\log (1+{\mathrm{\γ}}_{e_1}+{\mathrm{\γ}}_{e_2}+{\mathrm{\γ}}_{e_3})\]}^{+}.\end{array}---\left(21\right)$

By traveling through all possible γ₀,The safe capacity that can obtain maximum is

$\begin{array}{c}{C}_s={\max }_{{\mathrm{\&gamma;}}_0,{\mathrm{\&sigma;}}_{w_1}^2,{\mathrm{\&sigma;}}_{w_2}^2}{C}_s({\mathrm{\&gamma;}}_0,{\mathrm{\&sigma;}}_{w_1}^2,{\mathrm{\&sigma;}}_{w_2}^2)\\ \begin{array}{cc}s.t.& {\mathrm{\&gamma;}}_0>0,0<{\mathrm{\&sigma;}}_{w_1}^2<P_a^0\left({\mathrm{\&gamma;}}_0\right),0<{\mathrm{\&sigma;}}_{w_2}^2<P_b^0\left({\mathrm{\&gamma;}}_0\right)\end{array}\end{array}---\left(22\right)$

So that information can safe transmission, then must assure that safe capacity is more than 0.Observe formula (21) to understand, Make safe capacity be more than 0, must then be fulfilled for

Without loss of generality, normalization legitimate receipt end and the additive white Gaussian noise of transmitting terminal, i.e.Cause This, above-mentioned condition can be expressed as

$\begin{array}{c}\frac{P_b^0\left({\mathrm{\&gamma;}}_0\right)P_{\mathrm{\&alpha;}}^0\left({\mathrm{\&gamma;}}_0\right){\mathrm{\&sigma;}}_s^2}{\left(P_a^0\right({\mathrm{\&gamma;}}_0)+1){\mathrm{\&sigma;}}_{w_2}^2+P_b^0\left({\mathrm{\&gamma;}}_0\right)({\mathrm{\&sigma;}}_{w_2}^2-{\mathrm{\&sigma;}}_{w_1}^2)+2P_b^0\left({\mathrm{\&gamma;}}_0\right)P_a^0\left({\mathrm{\&gamma;}}_0\right)+P_a^0\left({\mathrm{\&gamma;}}_0\right)P_a^0\left({\mathrm{\&gamma;}}_0\right)+2P_a^0\left({\mathrm{\&gamma;}}_0\right)+P_b^0\left({\mathrm{\&gamma;}}_0\right)+1}\\ +\frac{{\mathrm{\&sigma;}}_s^2}{{\mathrm{\&sigma;}}_{w_1}^2+1}>\frac{{\mathrm{\&sigma;}}_s^2}{{\mathrm{\&sigma;}}_{w_1}^2}+\frac{{\mathrm{\&sigma;}}_s^2}{{\mathrm{\&sigma;}}_{w_1}^2+{\mathrm{\&sigma;}}_{w_2}^2+1}+\frac{P_b^0\left({\mathrm{\&gamma;}}_0\right){\mathrm{\&sigma;}}_s^2}{\left(P_b^0\right({\mathrm{\&gamma;}}_0)+1){\mathrm{\&sigma;}}_{w_2}^2+P_a^0\left({\mathrm{\&gamma;}}_0\right)+P_b^0\left({\mathrm{\&gamma;}}_0\right)+1},\end{array}---\left(23\right)$

As long as this inequality is set up, then system just can realize safe transmission.Meanwhile, this formula gives this Bright middle w₂Specific design thinking.

In order to proof scheme is realizing the superiority of secure context theoretically, the present invention has carried out following analysis.

Without loss of generality, it is assumed that transmitting terminal and legitimate receipt end have identical Power Limitation, i.e. P_a=P_bAndDue at given γ₀In the case of,WithIt is constant, so with a unified symbol p Represent, i.e.Simultaneously, it is assumed that the variance of the man made noise that first stage and second stage send is Identical, i.e.The man made noise w of phase III₃It is intended merely to introduce uncertainty, it is possible to considerTherefore, the left side of above-mentioned inequality and the right can be expressed as

$\begin{array}{c}f\left(x\right)=\frac{p-x}{x+1}+\frac{p^2(p-x)}{(p+1)x+3p^2+3p+1},\\ h\left(x\right)=\frac{p-x}{x}+\frac{p-x}{2x+1}+\frac{p(p-x)}{(p+1)x+2p+1},\end{array}---\left(1\right)$

Wherein, x < p.Thus, safe capacity can be expressed as

$C_s({\mathrm{\&gamma;}}_0,x)=\frac{1}{3}\&CenterDot;e^{-2{\mathrm{\&gamma;}}_0}\&CenterDot;log\frac{1+f\left(x\right)}{1+h\left(x\right)}.---\left(2\right)$

Can draw from this expression formula, as long as f (x) > h (x), safe rate just can be more than 0.F (x) > h (x) means The man made noise sent and be enough to protect the information of need for confidentiality.The situation of the limit is, almost all of available horsepower is used for Serve as man made noise, and these man made noises just can protect the secret signal slightly larger than 0, i.e. as x → p,Time, C_s→0⁺.Wherein C_s→0⁺Can be converted toI.e.This formula can be write as further

$\underset{x\&RightArrow;p}{\lim }\frac{f\left(x\right)-f\left(p\right)}{x-p}=\underset{x\&RightArrow;p}{\lim }\frac{h\left(x\right)-h\left(p\right)}{x-p},---\left(3\right)$

Wherein, f (p)=h (p)=0.According to the definition of derivative, above-mentioned formula can be write as f ' (p)=h ' (p), here f ' P () and h ' (p) represent f (x) and the h (x) derivative at x=p respectively.Solve equation f ' (p)=h ' (p), it can be deduced that p=p₀= 5.913.If it means that power p > p₀=5.913, exist for man made noiseMake transmitting terminal and reception End can be with secure communication.

This result indicates the advantage of the present invention, even if it means that eavesdropping end is in more favourable than legitimate receipt end Position (such as eavesdrop end clutch method end closer to), there is no antenna advantage, there is no outside aid, as long as there being enough transmission merits Rate, still can realize safety.And in traditional safety approach, not by antenna advantage or outside aid, as long as stealing Listen end channel quality better than legitimate receipt end, then even power is infinitely great, safe transmission can not be realized.

In order to from emulation upper checking present invention effect in terms of secure communication, accompanying drawing 2,3,4 give concrete emulation Result.

Accompanying drawing 2 gives safe capacity with the change of general power ratio shared by noise power.It can be seen that select suitably Noise power is so that safe capacity is more than 0, and the ratio that safe capacity can be made to account for general power along with noise power becomes Changing, when ratio is about 0.6, safe capacity reaches maximum.

Accompanying drawing 3 gives safe capacity change with transmit power under different artifact power.Obviously, merit is sent Rate is the biggest, and safe capacity is the biggest, and is almost linear increase when high s/n ratio.

Accompanying drawing 4 gives the curve that safe capacity changes with interrupt threshold.It will be seen that along with the increase of interrupt threshold, Safe capacity first increases and then decreases.Select suitable thresholding, so that safe capacity reaches maximum.

To sum up, the shortcoming that instant invention overcomes traditional scheme, do not eavesdrop end channel information, there is no antenna advantage, with And in the case of there is no outside aid, still can realize secure communication.

The invention is not limited in above-described embodiment, on the basis of technical scheme disclosed by the invention, the skill of this area Art personnel are according to disclosed technology contents, it is not necessary to some of which technical characteristic just can be made one by performing creative labour A little replacements and deformation, these are replaced and deformation is the most within the scope of the present invention.

Claims (9)

1. a cordless communication network allied signal feedback and man made noise's safety of physical layer communication means, it is characterised in that bag Include following step:

First stage, transmitting terminal uses channel inversion technique, mixes with variance be in information s of need for confidentialityArtificial Noise w₁, send first stage signal x_a1, it is ensured that send signal and meet first stage Power LimitationLegitimate receipt terminates Receive first stage informationAnd receive first stage Signal to Interference plus Noise Ratio accordinglyEavesdrop termination to receive and include needing protecting Close information s with mixing with variance isMan made noise w₁First stage informationEavesdrop end and receive corresponding the One stage received Signal to Interference plus Noise Ratio

Second stage, legitimate receipt end is also adopted by channel inversion technique, to transmitting terminal feedback signal x_b, this feedback signal is base The first stage information received is terminated in legitimate receiptInclude information s of need for confidentiality in feedback signal, mix with side Difference isMan made noise w₁, and mix and a certain amount of with variance beGauss man made noise w₂, it is ensured that feedback signal Meet second stage Power LimitationAnd mixed signal is fed back to transmitting terminal；Transmitting terminal receives in second stage Feedback signal y_a, transmitting terminal can be with variance beingMan made noise w₁Disappear；Eavesdrop end to receive at second stage signal y_e2, eavesdrop end can not with man made noise w₁Disappear；Eavesdrop termination and receive corresponding second stage reception Signal to Interference plus Noise Ratio γ_e2；

Phase III, transmitting terminal still uses channel inversion technique, be sent in feedback signal include need for confidentiality information s, With variance it isGauss man made noise w₂, and be contaminated with variance and beGauss man made noise w₃SignalEnsure Send signal and meet Power LimitationLegitimate receipt end receives second stage signalReceiving terminal can be w₂Disappear；Close Method receiving terminal receives corresponding second stage and receives Signal to Interference plus Noise RatioEavesdrop end and receive phase III signalEavesdrop end Can not be w₂Disappear, w₂Sufficiently large infringement is caused to eavesdropping end；Eavesdrop termination corresponding phase III reception Signal to Interference plus Noise Ratio γ_e3；

By introducing extra first stage variance it isGauss man made noise w₁, second stage variance beHigh this person Work noise w₂With phase III variance it isGauss man made noise w₃, and ensure that second stage feedback signal meets second-order simultaneously Section Power LimitationAnd first stage and phase III send signal and meet first stage Power LimitationAnd want MakeAnd then shouldPower Limitation should be all higher than the power threshold p set₀, make ?WithLess than Power LimitationLess than Power LimitationThus realize between transmitting terminal and receiving terminal Secure communication.

Method the most according to claim 1, it is characterised in that in the described first stage, work as channel coefficients | h_AB|²More than cutting Disconnected thresholding γ₀Time, transmitting terminal use channel inversion technique transmission signal:

x_a1=(s+w₁)/h_AB

Wherein, s is the information of need for confidentiality, w₁Being the Gauss man made noise mixed the first stage, its average is 0, and variance ish_ABIt it is the transmitting terminal channel to receiving terminal.

Method the most according to claim 2, it is characterised in that the Power Limitation of transmitting terminalS and w₁Side Difference must is fulfilled for

Wherein,For the variance of the information of need for confidentiality, P_aThe transmit power instantaneous for transmitting terminal limits,For asking for 1/ | h_AB|²Meansigma methods, wherein p (x) is channel coefficients | h_AB|²Probability density Function.

Method the most according to claim 1, it is characterised in that in the described first stage, legitimate receipt termination receives first Session information:

$y_{b_1}=h_{AB}{x}_{a1}+n_{b1}=h_{AB}\&CenterDot;\frac{1}{h_{AB}}(s+w_1)+n_{b1}=s+w_1+n_{b1}$

Wherein, h_ABFor the channel of transmitting terminal to receiving terminal,For legitimate receipt end at the additive white Gaussian noise of first stage, all Value is 0, and variance is

Eavesdrop termination and receive first stage information:

$y_{e_1}=h_{AE}{x}_{a1}+n_{e1}=h_{AE}\&CenterDot;\frac{1}{h_{AB}}(s+w_1)+n_{e1}=\frac{h_{AE}}{h_{AB}}s+\frac{h_{AE}}{h_{AB}}{w}_1+n_{e1}$

Wherein, h_AEIt is transmitting terminal to eavesdropping the channel of end, n_e1Being to eavesdrop to hold the additive white Gaussian noise in the first stage, average is 0, variance is

Method the most according to claim 1, it is characterised in that in described second stage, meet condition at channel coefficients | h_BA |²＞ γ₀Time, to transmitting terminal feedback signal:

$x_b=\mathrm{\&alpha;}\&CenterDot;(y_{b_1}+w_2)/h_{BA}$

α is to ensure that feedback signal meets Power LimitationCoefficient,It is expressed as:

Wherein,For the variance of the information of need for confidentiality, P_bThe transmit power instantaneous for transmitting terminal limits,For sending letter Number Power Limitation,For asking for 1/ | h_BA|²Meansigma methods, wherein q (x) is channel coefficients | h_BA|² Probability density function.

Method the most according to claim 1, it is characterised in that in described second stage, transmitting terminal is connected on second stage and receives To feedback signal be

$y_a=\mathrm{\&alpha;}(s+w_1+w_2+n_{b_1})+n_a$

Wherein, n_aBeing the additive white Gaussian noise of transmitting terminal, average is 0, and variance isα is the coefficient meeting Power Limitation, table It is shown as:

Wherein,For the variance of the information of need for confidentiality,For the variance yields of the additive white Gaussian noise of receiving terminal,For asking for 1/ | h_AB|²Meansigma methods, wherein p (x) is channel coefficients | h_AB|²Probability density Function；

Transmitting terminal can be w₁Disappearing, disappear w₁After reception signal be

${\tilde{y}}_a=\mathrm{\&alpha;}s+\mathrm{\&alpha;}(w_2+n_{b_1})+n_a$

But, eavesdrop the signal y that end receives in second stage_e2, eavesdrop end can not with man made noise w₁Disappear；Eavesdrop end Receive second stage signal y_e2For

$y_{e2}=\mathrm{\&alpha;}\frac{h_{BE}}{h_{BA}}s+\mathrm{\&alpha;}\frac{h_{BE}}{h_{BA}}(w_1+n_{b_1}+w_2)+n_{e_2}$

Wherein,Being to eavesdrop to hold the additive white Gaussian noise in second stage, average is 0, and variance ish_BEIt is that receiving terminal arrives steathily Listen the channel of end,For legitimate receipt end at the additive white Gaussian noise of first stage, average is 0, and variance is

Method the most according to claim 1, it is characterised in that in the described phase III, when channel coefficients meets | h_AB|²＞ γ₀Time, transmission signal:

$x_{a_2}=\mathrm{\&beta;}({\tilde{y}}_a+w_3)/h_{AB}$

Wherein,For the w that disappears₁After reception signal, β be to ensure that transmission signal meet Power LimitationCoefficient,It is expressed as:

Wherein,For the variance of the information of need for confidentiality,For asking for 1/ | h_AB|²Meansigma methods, Wherein p (x) is channel coefficients | h_AB|²Probability density function.

Method the most according to claim 1, it is characterised in that in the described phase III, legitimate receipt end receive second Stage signal is

$y_{b_2}=\mathrm{\&beta;}\mathrm{\&alpha;}s+\mathrm{\&beta;}\mathrm{\&alpha;}(w_2+n_{b_1})+\mathrm{\&beta;}(n_a+w_3)+n_{b_2}$

Wherein,Being the legitimate receipt end additive white Gaussian noise in the phase III, average is 0, and variance isReceiving terminal receives Signal becomes

${\tilde{y}}_{b2}=\mathrm{\&beta;}\mathrm{\&alpha;}s+{\mathrm{\&beta;\&alpha;n}}_{b_1}+\mathrm{\&beta;}(n_a+w_3)+n_{b_2}$

Now, the reception phase III signal eavesdropping end is

$y_{e_3}=\frac{h_{AE,2}}{h_{AB}}\mathrm{\&beta;}\mathrm{\&alpha;}s+\frac{h_{AE,2}}{h_{AB}}\left(\mathrm{\&beta;}\mathrm{\&alpha;}\right(w_2+n_{b_1})+\mathrm{\&beta;}(n_a+w_3\left)\right)+n_{e_3}$

Wherein,Being to eavesdrop to hold the additive white Gaussian noise in the phase III, average is 0, and variance ish_AE,2It is to eavesdrop end to exist The channel of phase III.

Method the most according to claim 1, it is characterised in that the legitimate receipt end in first and third stage receives accordingly Signal to Interference plus Noise Ratio is:

${\mathrm{\&gamma;}}_{b_1}=\frac{{\mathrm{\&sigma;}}_s^2}{{\mathrm{\&sigma;}}_{w_1}^2+{\mathrm{\&sigma;}}_b^2},{\mathrm{\&gamma;}}_{b_2}=\frac{{\mathrm{\&beta;}}^2{\mathrm{\&alpha;}}^2{\mathrm{\&sigma;}}_s^2}{{\mathrm{\&beta;}}^2{\mathrm{\&alpha;}}^2{\mathrm{\&sigma;}}_b^2+{\mathrm{\&beta;}}^2({\mathrm{\&sigma;}}_a^2+{\mathrm{\&sigma;}}_{w_3}^2)+{\mathrm{\&sigma;}}_b^2}$

The white Gaussian noise of end is eavesdropped in first, second and third stageTime, eavesdropping end reception Signal to Interference plus Noise Ratio is

${\mathrm{\&gamma;}}_{e_1}=\frac{{\mathrm{\&sigma;}}_s^2}{{\mathrm{\&sigma;}}_{w_1}^2},{\mathrm{\&gamma;}}_{e_2}=\frac{{\mathrm{\&sigma;}}_s^2}{{\mathrm{\&sigma;}}_{w_1}^2+{\mathrm{\&sigma;}}_{w_2}^2+{\mathrm{\&sigma;}}_b^2},{\mathrm{\&gamma;}}_{e_3}=\frac{{\mathrm{\&alpha;}}^2{\mathrm{\&sigma;}}_s^2}{{\mathrm{\&alpha;}}^2({\mathrm{\&sigma;}}_{w_2}^2+{\mathrm{\&sigma;}}_b^2)+{\mathrm{\&sigma;}}_a^2+{\mathrm{\&sigma;}}_{w_3}^2}$

Wherein,For the variance of the information of need for confidentiality,For the variance of the additive white Gaussian noise of transmitting terminal,Connect for legal Receiving end is in the variance of the additive white Gaussian noise of first stage, and α is for ensureing that feedback signal meets Power Limitation Coefficient, β is for ensureing that sending signal meets Power LimitationCoefficient.