CN104918238A - Cooperation interference excitation method for realizing physical layer safety - Google Patents

Abstract

The invention provides a cooperation interference excitation method for realizing physical layer safety in the mobile communication technical field. The invention provides an excitation measure based on paid cooperation interference service according to energy finiteness and selfishness of cooperation nodes. The method comprises the steps: collecting channel state information of each cooperation node and selecting an appropriate node to carry out cooperation interference; a legal communication source node giving initial service total compensation m according to the service need of itself; carrying out gaming of the service total compensation m between the source node and the cooperation nodes by utilizing a Stackelberg gaming method; and carrying out gaming of each obtained compensation mi between the cooperation nodes by utilizing the Stackelberg gaming method. Through double gaming processes, the source node is allowed to obtain the cooperation interference service, of which the cost performance is optimal; and meanwhile, optimum allocation of cooperation power and compensation of each cooperation node is realized.

Description

A kind of motivational techniques realizing the cooperation interference of safety of physical layer

Technical field

The present invention relates to mobile communication technology field, be specifically related to a kind of motivational techniques realizing the cooperation interference of safety of physical layer.

Background technology

Along with the develop rapidly of wireless communication technology, and the application of wireless communication technology is more and more general, and wireless communication technology has infiltrated through the every aspect of common people's life, for we bring more own and convenient.But some problems that himself exists also day by day highlight, and the deficiency especially in the safe and reliable guarantee of information, receives all the more the concern of people.Particularly in recent years, in order to realize the network coverage widely and message transmission rate faster, the cooperating relay communication technology is suggested and is widely used.Also just due to the introducing of more cooperative relay network interior joint, make network configuration complicated all the more, opening is also stronger, and therefore, the communication information is more easily ravesdropping, intercept and capture, and the safety of the communication information faces larger threat and challenge.

Within 1975, American scholar Wyner is according to the concept of extending secrecy capacity in the theory of Shannon secure communication, proposes the concept of safety of physical layer communication first.Subsequently, the technology of safety of physical layer is applied to cooperative relay system by the people such as Dabora, Dong, and proposes the multiple cooperative strategies such as amplification forwarding, decoding forwarding and cooperation interference to improve system safety performance.

The current research for safety of physical layer technology in relay cooperative network, more that research is under the prerequisite having certain energy constraint to transmission node, carry out the optimization process of optimum sensor selection problem and cooperation transmission signal, to reach the object maximizing inter-node link safe capacity.But in considered relay cooperative network, the node in network is generally the passive bus of finite energy.Therefore each node is in order to the optimal utilization of the maximum respective energy, and other nodes of active assistance of being reluctant carry out safety of physical layer communication.For this, the cooperation security service that the scholars such as Han propose cooperative node and provide is paid service, utilizes game theoretic method to encourage playing an active part in of cooperative node.Han for amplification forwarding, decoding forwards and multiple cooperative scene such as cooperation interference etc. is all discussed and analyzes, but the multiple legitimate correspondence user of the scene Main Analysis disturbed for cooperating competes single cooperation interfering nodes and two scenes disturbing cooperative node to serve a legitimate correspondence user.But the incentive mechanism of existing security cooperation interference, require higher for communication quality between cooperative node limited energy and legitimate correspondence user, need multiple cooperative node jointly to provide the scene of interference service, do not provide definite solution.

Summary of the invention

(1) technical problem solved

For the deficiencies in the prior art, the invention provides a kind of motivational techniques realizing the cooperation interference of safety of physical layer, require higher for communication quality between cooperative node limited energy and legitimate correspondence user, multiple cooperative node is needed jointly to provide the scene of interference service, provide effective incentives strategy, meeting between legitimate correspondence user while safe capacity requirement, the every a energy of cooperative node collection is made all to obtain maximized income and the most reasonably utilize.

(2) technical scheme

In order to reach above object, the present invention is achieved by the following technical programs:

Realize motivational techniques for the cooperation interference of safety of physical layer, the method comprises:

S1: source node collects the channel condition information of destination node and eavesdropping node;

S2: source node, according to the improvement effect of each cooperative node to the safe capacity of source node, selects the cooperative node that can realize secure communication as alternative cooperative node;

S3: source node according to the business demand of self, its total recompense m of service that can pay of initialization, and determine that it passes through cooperation interfering process obtainable benefit U _s;

S4: utilize Stackelberg game method, carries out game to the total recompense m of service, and determines the optimum total recompense of service according to source node benefit function between source node and cooperative node collection;

S5: utilize Stackelberg game method, carries out apportionment games to the total recompense of optimal service, and determines the getable optimum benefit of each cooperative node between each cooperative node, and tries to achieve respective service recompense m _iand separately needed for the cooperation interference power P that provides _i.

Preferably, the channel condition information of described destination node and eavesdropping node comprises: source node is respectively G to the channel condition information of destination node and eavesdropping node _sdand G _se; And each cooperation interfering nodes is respectively G to destination node and the channel condition information of eavesdropping node _idand G _ie.

Preferably, the computing formula of described each cooperative node to the improvement effect of the safe capacity of source node is:

C _{s_i}=(C _{sd_i}-C _{se_i}) ⁺

Wherein:

C _{s_i}for source node provides the safe capacity disturbed under service at a certain cooperative node to destination node;

C _{sd_i}for source node is to the channel capacity of destination node, expression formula is:

$C_{\mathrm{sd}\_i}={\log }_2(1+\frac{P_s{G}_{\mathrm{sd}}}{{\mathrm{\σ}}^2+P_i{G}_{\mathrm{id}}})$

C _{se_i}for source node is to the channel capacity of eavesdropping node, expression formula is:

$C_{\mathrm{se}\_i}={\log }_2(1+\frac{P_s{G}_{\mathrm{se}}}{{\mathrm{\σ}}^2+P_i{G}_{\mathrm{ie}}})$

Wherein, P _sand P _ibe respectively the transmitting power that source node adopts with cooperation interfering nodes, and σ ²then represent the thermal noise power at eavesdropping node and destination node.

Preferably, the safe capacity C of source node realization at destination node place can be assisted _{s_i}be greater than the cooperative node of 0, alternative cooperative node will be chosen as.

Preferably, described source node is by the income U of cooperation interference acquired by service process _s, depend on the size of the recompense of the safe capacity that obtains of source node and required payment in cooperation interference service process, its concrete expression formula is:

$\begin{array}{c}{U}_s=({\log }_2(1+\frac{A}{1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{u}_j{P}_j})-{\log }_2(1+A))\\ -({\log }_2(1+\frac{B}{1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{P}_j})-{\log }_2(1+B))\\ -m\end{array}$

Wherein:

$A\stackrel{\mathrm{\Δ}}{=}\frac{P_s{G}_{\mathrm{sd}}}{{\mathrm{\σ}}^2}$

$B\stackrel{\mathrm{\Δ}}{=}\frac{P_s{G}_{\mathrm{se}}}{{\mathrm{\σ}}^2}$

$u_i\stackrel{\mathrm{\Δ}}{=}\frac{P_i{G}_{\mathrm{id}}}{{\mathrm{\σ}}^2}$

$v_i\stackrel{\mathrm{\Δ}}{=}\frac{G_{\mathrm{ie}}}{{\mathrm{\σ}}^2}$

Wherein, P _jrepresent the transmitting power that in cooperation interfering nodes collection ψ, cooperative node j adopts.

Preferably, whole cooperation interfering process, selects multiple cooperation interfering nodes to form cooperation interference collection and jointly provides service in cooperative node, and the obtainable recompense m of each cooperative node _i, depend on that the interference service provided separately is to the improvement degree of main channel safe capacity, is specifically expressed as:

$m_i=m\left(\frac{P_i{G}_{\mathrm{ie}}-P_i{G}_{\mathrm{id}}}{{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}-P_j{G}_{\mathrm{jd}}}\right).$

Preferably, each cooperative node is by providing cooperation interference service, and obtainable benefit is expressed as:

$U_i=m\left(\frac{P_i{G}_{\mathrm{ie}}-P_i{G}_{\mathrm{id}}}{{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}-P_j{G}_{\mathrm{je}}}\right)-a{P}_i$

Wherein, a is the gain corresponding to per unit of power.

Preferably, in each cooperative node power one timing, the optimum benefit of source node depends on the size of the total recompense m of paid service.For described benefit function U _sbe independent variable with m, ask first derivative, namely

$\frac{{{\∂U}_s}^{*}}{\∂m}=0$

U is obtained by above formula _sabout the extreme point m of independent variable m ^*, and U _ssecond dervative about independent variable m is less than 0, and function U is described _sbe the concave function about m, namely obtain maximum at obtained extreme point place.

Preferably, in total recompense one timing of system, the optimum benefit of each cooperative node depends on its interference power P provided _isize.For described U _ithink P _iindependent variable, asks first derivative, namely

$\frac{{\∂U}_i}{\∂P_i}=0$

U is obtained by above formula _iabout independent variable P _iextreme point P _i ^*, and U _iabout independent variable P _isecond dervative be less than 0, function U is described _iabout P _iconcave function, namely obtain maximum at obtained extreme point place.

Preferably, the method also comprises: by the cooperation interference power P of each cooperative node of step 5 gained _isubstitute in the benefit function of source node in step S4, so circulate, finally try to achieve total service recompense value m that the overall situation is uniquely stable, and the interference power P of corresponding each cooperative node _i, this equilibrium point is the Nash Equilibrium Solution of Stackelberg game.

(3) beneficial effect

The present invention has following beneficial effect at least:

Present invention is directed at communication quality requirement between cooperative node limited energy and legitimate correspondence user higher, multiple cooperative node is needed jointly to provide the scene of interference service, propose to utilize the method for Stackelberg game effectively to encourage many cooperative nodes to carry out cooperation interference service, simultaneously by the strategy of double-deck game, make while source node obtains optimum safe capacity with rational recompense, make every part that provides power of each cooperation interfering nodes obtain maximum value.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these figure.

Fig. 1 is a kind of flow chart realizing the motivational techniques of the cooperation interference of safety of physical layer in the embodiment of the present invention;

Fig. 2 is the structure chart of the multi-node collaboration interference model in the embodiment of the present invention;

Fig. 3 shows the safe capacity of Stackelberg game strategies and uniform distribution strategy and the contrast of observable index;

Fig. 4 shows the average interference power contrast in different cooperation interfering nodes participation situation;

When Fig. 5 shows different cooperation interfering nodes participation, the obtainable maximum safe capacity of source node;

Fig. 6 shows cooperation interfering nodes number when being 8, the power division of each cooperation interfering nodes.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

As shown in Figure 1, be the motivational techniques realizing the cooperation interference of safety of physical layer a kind of in the embodiment of the present invention, the method comprises the following steps:

S1: source node collects the channel condition information of destination node and eavesdropping node;

S2: source node, according to the improvement effect of each cooperative node to the safe capacity of source node, selects the cooperative node that can realize secure communication as alternative cooperative node;

S3: source node according to the business demand of self, its total recompense m of service that can pay of initialization, and determine that it passes through cooperation interfering process obtainable benefit U _s;

S4: utilize Stackelberg (Stackelberg) game method, carries out game to the total recompense m of service, and determines the optimum total recompense of service according to source node benefit function between source node and cooperative node collection;

S5: utilize Stackelberg game method, carries out apportionment games to the total recompense of optimal service, and determines the getable optimum benefit of each cooperative node between each cooperative node, and tries to achieve respective service recompense m _iand separately needed for the cooperation interference power P that provides _i.

And the cooperative communication network model that the embodiment of the present invention is considered as shown in Figure 2, the system considered comprises a source node S, destination node D, an eavesdropping node E and N number of cooperation interfering nodes J _i, i ∈ N, N={1,2 ... n}.Here mentioned node all adopts single antenna and works in semiduplex pattern, and namely each node can not carry out the receipts of data simultaneously and send out operation.Eavesdropping node attempts the information that eavesdropping source node sends all the time.When being weaker than source to the main channel quality of object from source node to the internodal tapping channel quality of eavesdropping, the both sides of legitimate correspondence can ensure securely communicate with the speed of non-zero and be not ravesdropping.The speed of the maximum safe transmission that this can reach by we from source node to destination node is called safe capacity.Safe rate is then the justifiable rate lower than safe capacity.When main channel is second-rate and when being weaker than tapping channel, in order to ensure the fail safe of destination node received information, just need the assistance resorting to interfering nodes, send artificial interference signal to destroy the quality of tapping channel by interfering nodes, thus build the environment that can securely communicate.

Be directed to the communication scenes of interfering nodes cooperation, whole communication process comprises two parts: Part I, and source node S is with power P _ssignal is sent to destination node D, and this information also will be ravesdropping node and eavesdropped simultaneously, now G _sdand G _sebe respectively link S → D, the channel gain on S → E.Part II, interfering nodes J _iwith power P _ithe artificial interference signal of external transmission, now link J _i→ D and J _ithe channel gain of → E is respectively G _idand G _ie.Here suppose that source node can obtain the transient channel information of every bar communication channel, and every bar channel all obeys the Rayleigh fading of Flat quasistatic, in path loss model, path loss coefficient is set to α, is represented as σ at the thermal noise power of eavesdropping node and destination node ².

Be directed to the scene that between cooperative node limited energy or legitimate correspondence user, channel quality is poor, in order to ensure the secure communication quality between legitimate correspondence user, need multiple cooperation interfering nodes to form cooperation interference collection and carry out associating interference, now destination node and the obtainable channel capacity of eavesdropping node are expressed as C _sdand C _se,

$C_{\mathrm{sd}}={\log }_2(1+\frac{P_s{G}_{\mathrm{sd}}}{{\mathrm{\σ}}^2+{\mathrm{\Σ}}_{i\∈N}{P}_i{G}_{\mathrm{id}}})---\left(1\right)$

$C_{\mathrm{se}}={\log }_2(1+\frac{P_s{G}_{\mathrm{se}}}{{\mathrm{\σ}}^2+{\mathrm{\Σ}}_{i\∈N}{P}_i{G}_{\mathrm{ie}}})---\left(2\right)$

In order to ensure that data that source node sends are not ravesdropping node and intercept and capture, source node should with C _ssafe capacity carry out transfer of data:

C _s=(C _sd-C _se) ⁺(3)

Wherein can find out due to cooperative node send the impact of interference, C _sdand C _seall reduced accordingly, how to select the power of interfering nodes and distribution interfering nodes will finally affect acquired C _seffect.And the safe capacity C of source node realization at destination node place can be assisted _sbe greater than the cooperative node of 0, participate in be chosen as alternative cooperative node in follow-up cooperation interference service process.

Cooperation is participated in the secure communication demand meeting validated user in order to encourage more node, guarantee that recompense and power used distribute efficiently between many cooperative nodes, Stackelberg game is used and analyzes its impact promoted for system safety performance simultaneously.

In designed game scene, source node S is expected by from cooperative node J _ithe safe capacity of oneself is optimized in the interference " service " that place buys.Therefore its utility function U _sbe represented as:

maxU _s=max(C _s-m) ⁺(4)

Wherein m be source node S pay total recompense of all cooperation interfering nodes.

Corresponding cooperation interfering nodes J _ithe source node being then responsible for demand provides paid interference service, and it is by asking for recompense to acquire an advantage from source node, therefore its utility function U _iobtain by its difference between recompense and the cost paid:

maxU _i=max(m _i-aP _i) ⁺(5)

Wherein a is the gain corresponding to per unit of power, and m _ithen cooperation interfering nodes J _ithe recompense obtained, it depends on that this node is for the contribution improving main channel safe capacity.

$m_i=m\left(\frac{P_i{G}_{\mathrm{ie}}-P_i{G}_{\mathrm{id}}}{{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}-P_j{G}_{\mathrm{jd}}}\right)---\left(6\right)$

In formula, territory ψ is all node set participating in cooperation interference, and P _jit is then the interference power that in the ψ of territory, each cooperation interfering nodes adopts.

Be easy to find from publicity (4) and (5), only have when source node and cooperative node can be made a profit from this gambling process, it is just ready to participate in this gambling process.We utilize the method for Stackelberg game to carry out the design and optimization of game strategies, therefore source node is the buyer in gambling process, and cooperative node is then the auctioneer in gambling process.

Source node end is sentence optimum price from cooperative node to buy interference service as much as possible to improve the safe capacity desired by it as its target of buyer.Therefore its utility function specifically can be expressed as:

$\begin{array}{c}{U}_s=({\log }_2(1+\frac{A}{1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{u}_j{P}_j})-{\log }_2(1+A))\\ -({\log }_2(1+\frac{B}{1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{P}_j})-{\log }_2(1+B))\\ -m\end{array}---\left(7\right)$

Wherein

$A\stackrel{\mathrm{\Δ}}{=}\frac{P_s{G}_{\mathrm{sd}}}{{\mathrm{\σ}}^2}---\left(8\right)$

$B\stackrel{\mathrm{\Δ}}{=}\frac{P_s{G}_{\mathrm{se}}}{{\mathrm{\σ}}^2}---\left(9\right)$

$u_i\stackrel{\mathrm{\Δ}}{=}\frac{P_i{G}_{\mathrm{id}}}{{\mathrm{\σ}}^2}---\left(10\right)$

$v_i\stackrel{\mathrm{\Δ}}{=}\frac{G_{\mathrm{ie}}}{{\mathrm{\σ}}^2}---\left(11\right)$

Suppose P _i=ρ _im, then for formula (7), the benefit that it obtains when cooperative node is fixed is relevant with the total recompense paid, and asks local derviation to obtain formula (7) for m

$\begin{array}{c}\frac{{\∂U}_s}{\∂m}=\frac{B{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{P}_j}{\ln 2(1+B+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{P}_{j}m)(1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{P}_{j}m)}\\ -\frac{A{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{u}_j{P}_j}{\ln 2(1+A+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{u}_j{P}_{j}m)(1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{u}_j{P}_{j}m)}-1\end{array}---\left(12\right)$

Formula (12) be solved to closed solutions, the solution procedure of its closed solutions is too complicated, in order to reduce system complexity, we are by System Model Reduction: by the preliminary treatment for interference signal, make interference signal only impact eavesdropping Nodes and can not reduce the channel quality at destination node place, thus the utility function at source node place is changed to:

$\begin{array}{c}{U}_s=({\log }_2(1+B)-{\log }_2(1+\frac{B}{1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{P}_j}))\\ -m\end{array}---\left(13\right)$

For source node, it only has when formula (13) equals 0 about the local derviation of m, the benefit extreme value that it obtains:

$\begin{array}{c}\frac{{{\∂U}_s}^{*}}{\∂m}=\frac{B{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_j}{\ln 2(1+B+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_{j}m)(1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_{j}m)}\\ -1=0\end{array}---\left(14\right)$

Rearrange formula (14) can obtain

$m^2+\frac{(B+2)m}{{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_j}+\frac{1+B-B{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_j/\ln 2}{{\left({\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_j\right)}^2}=0---\left(15\right)$

Therefore the closed solutions for formula (15) is

$m^{*}=-\frac{B+2}{2K}+\sqrt{\frac{{(B+2)}^2}{4K^2}-\frac{(1+B-\mathrm{BK}/\ln 2)}{K^2}}---\left(16\right)$

Wherein K=∑ _{j ∈ J}v _jρ _j, consider the actual physics implication of m, m should be greater than 0 value, when m≤0, show that source node cannot obtain benefit by the help of cooperative node.

$\begin{array}{c}\frac{{\∂}^2{U_s}^{*}}{{\∂m}^2}=-\frac{B{\left({\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_j\right)}^2}{\ln 2{(1+B+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_{j}m)}^2(1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_{j}m)}\\ -\frac{B{\left({\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_j\right)}^2}{\ln 2(1+B+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_{j}m){(1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{\mathrm{\ρ}}_{j}m)}^2}\end{array}---\left(17\right)$

Known according to formula (17), U _ssecond dervative about m is minus, is the concave function about m.Therefore make U _sthe first derivative m value that equals 0 be in cooperative node power P _iwhen fixing, source node is made to obtain the point of greatest benefit.

According to formula (5) and (6), can find that the recompense that cooperative node can obtain is how many relevant with the total recompense given by the power that it is paid and source node, its utility function specifically can be expressed as:

$U_i=m\left(\frac{P_i{G}_{\mathrm{ie}}-P_i{G}_{\mathrm{id}}}{{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}-P_j{G}_{\mathrm{jd}}}\right)-a{P}_i---\left(18\right)$

In order to reach paid power and obtain optimal proportion between recompense, our hypothesis, when total recompense m is certain, asks U _iwith P _ibetween relation.P is asked to formula (18) _ilocal derviation be:

$\frac{{\∂U}_i}{{\∂P}_i}=m\frac{G_{\mathrm{ie}}}{{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}}-m\frac{P_i{G}_{\mathrm{ie}}^2}{{\left({\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}\right)}^2}-a---\left(19\right)$

When formula (19) equals 0 time, can in the hope of under the total recompense m fixing situation of system, power when making cooperative node obtain optimum benefit.

${P_i}^{*}=\frac{\sqrt{m{G}_{\mathrm{ie}}{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}/a}-{\mathrm{\Σ}}_{j\≠i}{P}_j{G}_{\mathrm{je}}}{G_{\mathrm{ie}}}---\left(20\right)$

The present invention is poor mainly for channel quality between cooperative node limited energy or legitimate correspondence user, needs multiple cooperation interfering nodes to carry out the scene of associating interference.When the nodes participating in cooperation interference is greater than 2, there is Nash Equilibrium in designed whole gambling process.

According to the definition of Nash Equilibrium, in order to reach Nash Equilibrium, each cooperation interfering nodes J _iall select the interference power of its optimum responsively.Otherwise interference cooperative node will be had and expect that its strategy of adjustment is to obtain better income.

Therefore, carry out distortion to formula (20) can obtain

${P_i}^{*}=\frac{C(m{G}_{\mathrm{ie}}-\mathrm{aC})}{m{G}_{\mathrm{ie}}^2}---\left(21\right)$

Wherein C=∑ _{j ∈ ψ}p _jg _je.

Combine the optimal response considering each cooperative node, therefore to all P _i ^*g _iecarry out suing for peace and just equal C, still can obtain P _i ^*new expression formula,

$\left\{\begin{array}{c}{P_i}^{*}=m\frac{(n-1)(E{G}_{\mathrm{ie}}-n+1)}{a{G}_{\mathrm{ie}}^2{E}^2}=m{\mathrm{\ρ}}_i\\ E={\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}\frac{1}{G_{\mathrm{ie}}}\end{array}\right.---\left(22\right)$

Wherein n is the quantity of the interfering nodes participating in cooperation.Can find out that the program is only applicable to multiple node and carries out the scene disturbed that cooperates, i.e. n >=2 simultaneously by formula (22).

$\frac{{\∂}^2{U}_i}{\∂{P^2}_i}=\frac{2P_i{G}_{\mathrm{ie}}^{3}m}{{\left({\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}\right)}^2}-\frac{2m{G}_{\mathrm{ie}}^2}{{\left({\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}\right)}^2}---\left(23\right)$

Can find about P from formula (23) _isecond dervative be less than 0, therefore U _iabout P _iconcave function.Can be found again to only have and work as by formula (22) time, cooperation interfering nodes just can be selected to carry out providing interference service.Otherwise work as time, required P _i ^*for negative value, in this case, this interference cooperative node then keeps silent status externally not carry out the transmission of interference signal.

According to the definition of Nash Equilibrium, when optimal response function be on the occasion of, dull, during easily extensible, the Nash Equilibrium of gambling process exists and unique.Obviously, P can be proved easily from formula (20) and (22) _i ^*meet above requirement, therefore the Nash Equilibrium of this gambling process existence anduniquess.

Present invention is directed at communication quality requirement between cooperative node limited energy and legitimate correspondence user higher, multiple cooperative node is needed jointly to provide the scene of interference service, propose to utilize the method for Stackelberg game effectively to encourage many cooperative nodes to carry out cooperation interference service, simultaneously by the strategy of double-deck game, make while source node obtains optimum safe capacity with rational recompense, make every part that provides power of each cooperation interfering nodes obtain maximum value.

Simulation analysis is carried out to the method mentioned in the embodiment of the present invention below, in order to verify the proposed excitation of interference cooperative node based on Stackelberg game and the performance of power distribution strategies, algorithm that the present invention carries will be analyzed with average power allocation strategy.In the communication scenes considered, comprise a source node, a destination node and an eavesdropping node, their their positions lay respectively at (0,0), (0,100), (50,50).In order to contrast the allocative efficiency of designed Stackelberg game playing algorithm for node power and recompense, we also discuss disturbance cooperative node participate under systematic function, wherein discussed cooperation interfering nodes number is as shown in table 1.For simplicity, selected cooperation interfering nodes all at eavesdropping near nodal, and then makes produced interference signal very little for the impact of destination node, even can ignore in computational process.Other parameters required in simulation process are as shown in table 1.According to above known to middle formula, the optimal power that gain corresponding to per unit of power calculates for system and system benefit have vital impact, therefore in simulation process, the value of a carries out dynamic change from 100 to 1000, to analyze the impact of different a for systematic function.

Table 1 cooperates EVAC (Evacuation Network Computer Model) parameter

Parameter	Value
		Source node transmitting power P s	0.02W
Path loss index α	3
		Noise power σ 2	10 -8W
Cooperative node number N	2,3,4,5,6,7,8

In order to verify the high efficiency of designed Stackelberg game for many cooperation interfering nodes power division, first we contrast with even power allocation strategy, as shown in Figure 3, no matter is at N _j=2 or N _jwhen=8, designed strategy can obtain higher safe capacity and always disturb power dissipation ratio, and namely proposed scheme can consume less power consumption and realize the effect of same safe capacity lifting.When Fig. 4 and Fig. 5 respectively show designed Stackelberg game strategies corresponding to different cooperation interfering nodes participation, the interference power of the required consumption of average each cooperative node and the obtainable maximum safe capacity of source node.From the angle of ensemble average, when there being multiple node to cooperate, each cooperation interfering nodes can adopt less power that source node can be made to obtain higher safe capacity.

But due to the difference of each nodal distance eavesdropping node location, its interference signal is also different for the impact of eavesdropping node, therefore can obviously find from Fig. 6, have 8 nodes cooperate simultaneously interference time, utilize Stackelberg game, for the game competition that gained recompense is carried out between different node, thus impel each node to adopt the most rational power to cooperate, thus realize the optimum safe capacity at source node place acquired in Fig. 5.

Above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that; It still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of various embodiments of the present invention technical scheme.

Claims (10)

1. realize motivational techniques for the cooperation interference of safety of physical layer, it is characterized in that, the method comprises:

S1: source node collects the channel condition information of destination node and eavesdropping node;

S2: source node, according to the improvement effect of each cooperative node to the safe capacity of source node, selects the cooperative node that can realize secure communication as alternative cooperative node;

S3: source node according to the business demand of self, its total recompense m of service that can pay of initialization, and determine that it passes through cooperation interfering process obtainable benefit U _s;

S4: utilize Stackelberg game method, carries out game to the total recompense m of service, and determines the optimum total recompense of service according to source node benefit function between source node and cooperative node collection;

S5: utilize Stackelberg game method, carries out apportionment games to the total recompense of optimal service, and determines the getable optimum benefit of each cooperative node between each cooperative node, and tries to achieve respective service recompense m _iand separately needed for the cooperation interference power P that provides _i.

2. motivational techniques according to claim 1, is characterized in that, the channel condition information of described destination node and eavesdropping node comprises: source node is respectively G to the channel condition information of destination node and eavesdropping node _sdand G _se; And each cooperation interfering nodes is respectively G to destination node and the channel condition information of eavesdropping node _idand G _ie.

3. motivational techniques according to claim 1, is characterized in that, the computing formula of described each cooperative node to the improvement effect of the safe capacity of source node is:

C _{s_i}=(C _{sd_i}-C _{se_i}) ⁺

Wherein:

C _{s_i}for source node provides the safe capacity disturbed under service at a certain cooperative node to destination node;

C _{sd_i}for source node is to the channel capacity of destination node, expression formula is:

$C_{\mathrm{sd}\_i}={\log }_2(1+\frac{P_s{G}_{\mathrm{sd}}}{{\mathrm{\σ}}^2+P_i{G}_{\mathrm{id}}})$

C _{se_i}for source node is to the channel capacity of eavesdropping node, expression formula is:

$C_{\mathrm{se}\_i}={\log }_2(1+\frac{P_s{G}_{\mathrm{se}}}{{\mathrm{\σ}}^2+P_i{G}_{\mathrm{ie}}})$

Wherein, P _sand P _ibe respectively the transmitting power that source node adopts with cooperation interfering nodes, and σ ²then represent the thermal noise power at eavesdropping node and destination node.

4. motivational techniques according to claim 3, is characterized in that, can assist the safe capacity C of source node realization at destination node place _{s_i}be greater than the cooperative node of 0, alternative cooperative node will be chosen as.

5. motivational techniques according to claim 1, is characterized in that, described source node is by the income U of cooperation interference acquired by service process _s, depend on the size of the recompense of the safe capacity that obtains of source node and required payment in cooperation interference service process, its concrete expression formula is:

$\begin{array}{c}{U}_s=({\log }_2(1+\frac{A}{1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{u}_j{P}_j})-{\log }_2(1+A))\\ -({\log }_2(1+\frac{B}{1+{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{v}_j{P}_j})-{\log }_2(1+B))\\ -m\end{array}$

Wherein:

$A\stackrel{\mathrm{\Δ}}{=}\frac{P_s{G}_{\mathrm{sd}}}{{\mathrm{\σ}}^2}$

$B\stackrel{\mathrm{\Δ}}{=}\frac{P_s{G}_{\mathrm{se}}}{{\mathrm{\σ}}^2}$

$u_i\stackrel{\mathrm{\Δ}}{=}\frac{P_i{G}_{\mathrm{id}}}{{\mathrm{\σ}}^2}$

$v_i\stackrel{\mathrm{\Δ}}{=}\frac{G_{\mathrm{ie}}}{{\mathrm{\σ}}^2}$

Wherein, P _jrepresent the transmitting power that in cooperation interfering nodes collection ψ, cooperative node j adopts.

6. motivational techniques according to claim 1, is characterized in that, whole cooperation interfering process, select multiple cooperation interfering nodes to form cooperation interference collection and jointly provide service in cooperative node, and the obtainable recompense m of each cooperative node _i, depend on that the interference service provided separately is to the improvement degree of main channel safe capacity, is specifically expressed as:

$m_i=m\left(\frac{P_i{G}_{\mathrm{ie}}-P_i{G}_{\mathrm{id}}}{{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}-P_j{G}_{\mathrm{jd}}}\right).$

7. motivational techniques according to claim 1, is characterized in that, each cooperative node is by providing cooperation interference service, and obtainable benefit is expressed as:

$U_i=m\left(\frac{P_i{G}_{\mathrm{ie}}-P_i{G}_{\mathrm{id}}}{{\mathrm{\Σ}}_{j\∈\mathrm{\ψ}}{P}_j{G}_{\mathrm{je}}-P_j{G}_{\mathrm{je}}}\right)-a{P}_i$

Wherein, a is the gain corresponding to per unit of power.

8. motivational techniques according to claim 5, is characterized in that, in each cooperative node power one timing, the optimum benefit of source node depends on the size of the total recompense m of paid service.For described benefit function U _sbe independent variable with m, ask first derivative, namely

$\frac{{{\∂U}_s}^{*}}{\∂m}=0$

U is obtained by above formula _sabout the extreme point m of independent variable m ^*, and U _ssecond dervative about independent variable m is less than 0, and function U is described _sbe the concave function about m, namely obtain maximum at obtained extreme point place.

9. motivational techniques according to claim 7, is characterized in that, in total recompense one timing of system, the optimum benefit of each cooperative node depends on its interference power P provided _isize.For described U _ithink P _iindependent variable, asks first derivative, namely

$\frac{{\∂U}_i}{\∂P_i}=0$

U is obtained by above formula _iabout independent variable P _iextreme point P _i ^*, and U _iabout independent variable P _isecond dervative be less than 0, function U is described _iabout P _iconcave function, namely obtain maximum at obtained extreme point place.

10., according to the said motivational techniques of claim 1, it is characterized in that, the method also comprises:

By the cooperation interference power P of each cooperative node of step 5 gained _isubstitute in the benefit function of source node in step S4, so circulate, finally try to achieve the interference power P of the uniquely stable total service recompense value m of the overall situation and corresponding each cooperative node _i, this equilibrium point is the Nash Equilibrium Solution of Stackelberg game.