CN103442420A - High-energy-efficiency resource optimization method based on advance and retreat method and golden section method - Google Patents

Abstract

The invention discloses a high-energy-efficiency resource optimization method based on an advance and retreat method and a golden section method. The high-energy-efficiency resource optimization method comprises the following steps of: establishing a mathematical model of the energy efficiency of a D2D (device-to-device) communication system on the premise that the energy efficiency of D2D users in term of occupied frequency spectrum resources is optimal; analyzing to find that the mathematical model can be decomposed into two layers of independent optimization problems, namely power control for the first layer and resource distribution for the second layer; in the first layer of optimization problems, respectively optimizing the self energy efficiency of each group of the D2D users in term of respective viable resources at first, proving that a corresponding energy efficiency function must have an optimal solution if having a characteristic of descending or ascending at first and then descending, then working out the optimal solution by adopting the advance and retreat method and the golden section method; putting forward a heuristic resource distribution method in the second layer of the optimization problems. The high-energy-efficiency resource optimization method can improve the energy efficiency of a D2D system for mobile communication and meets requirements for green communication and prolonging the battery service time of a mobile terminal.

Description

High energy efficiency method for optimizing resources based on advance and retreat method and Fibonacci method

Technical field

The present invention relates to mobile communication resources and distribute and power control techniques, relate in particular to the high energy efficiency method for optimizing resources based on advance and retreat method and Fibonacci method in the straight-through cellular communication system of a kind of terminal.

Background technology

At present, for solving the frequency spectrum resource anxiety and improving traffic rate, the common employing speed of people D2D(device-to-device high, low in energy consumption) technology, it is the straight-through technology of cellular terminal, but the D2D technology has strengthened the phone user to be disturbed cellular link D2D user's interference and D2D user, thereby reduces the data transmission rate between communication.

Along with green communications receive people's concern day by day, how by resource, distribute and power controls to improve the efficiency of D2D system, be that current D2D technology is urgently to be resolved hurrily.

Summary of the invention

Goal of the invention: in order to overcome the deficiencies in the prior art, the invention provides the high energy efficiency method for optimizing resources based on advance and retreat method and Fibonacci method in the straight-through cellular communication system of a kind of terminal, improve the D2D system energy efficiency.

Technical scheme: for achieving the above object, the technical solution used in the present invention is:

High energy efficiency method for optimizing resources based on advance and retreat method and Fibonacci method, be included in and guarantee that D2D user, under the optimum prerequisite of efficiency on shared frequency spectrum resource, has set up the Mathematical Modeling of D2D communication system efficiency; Find that by analysis this Mathematical Modeling can be decomposed into two-layer independently optimization problem: ground floor is that power is controlled, and the second layer is that resource is distributed; At first considered that in the ground floor optimization problem every group of D2D user is optimized self efficiency respectively on feasible resource separately, and proved that corresponding efficiency function has and successively decrease or first increase progressively the character of successively decreasing afterwards, just necessarily there is optimal solution in it, adopts advance and retreat method and Fibonacci method to try to achieve optimal solution; A kind of heuristic resource allocation algorithm has been proposed in second layer optimization problem.Comprise the steps:

(1) set up the target function of efficiency, suc as formula (1)

$\max U_{\mathrm{EE}}=\underset{i=1}{\overset{N_d}{\mathrm{\Σ}}}\frac{\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{x}_{i,j}\·R\left(p_{i,j}\right)}{\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{x}_{i,j}\·p_{i,j}+P_C}---\left(1\right)$

This target function comprises following constraints:

1. every group of minimum transmission rate request that D2D is right, minimum transmission rate can not be less than γ _i, the minimum transmission rate that D2D on the same group is not right can be different, to meet business need:

$R\left(p_{i,j}\right)\≥{\mathrm{\γ}}_i,\∀i,\∀j$

2. must be less than certain value τ to the phone user that shares same resource block to two D2D users' of this group D2D centering interference power with one group of D2D, the interference of bearing due to the reception user is larger, generally can think that the interference power to receiving the user must be less than certain value τ:

$p_{I,k,i}\·h_{k,i}\≤\mathrm{\τ},{\∀x}_{i,j}=1$

3. x _i,jget 1 expression i group D2D multiplexing to selecting j Resource Block to carry out, x _i,jget 0 expression i group D2D to not selecting j Resource Block to carry out multiplexing:

$x_{i,j}\∈\left\{\mathrm{0,1}\right\},\∀i,\∀j$

4. every group of D2D is to Resource Block that can and can only a multiplexing phone user:

$\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{x}_{i,j}=1,\∀i$

5. each phone user's Resource Block at most can only be by one group of D2D to multiplexing:

$\underset{i=1}{\overset{N_d}{\mathrm{\Σ}}}{x}_{i,j}\≤1,\∀j$

6. D2D user's maximum transmission power limits:

$0\≤p_{i,j}\≤p_{\max },\∀i,\∀j$

Every group of D2D centering comprises two D2D users, and one of them is for receiving the user, and another is for sending the user;

Wherein: N _dmean the right group number of D2D, M means the number of allowable resource piece, and i means i group D2D couple, and j means j Resource Block, and k means the sequence number to the phone user of multiplexing same resource block with i group D2D; U _eEmean the efficiency sum that all D2D are right; $R\left(p_{i,j}\right)=w\·{\log }_2(1+\frac{p_{i,j}\·h_{D,i}}{p_{I,k,i}\·h_{k,i}+{\mathrm{\σ}}^2}),$ Speed while meaning i group D2D to multiplexing j Resource Block; p _i,jmean that i group D2D is to the through-put power on j Resource Block, P _cmean the power (not being subject to the impact of D2D on through-put power) that on mobile terminal, circuit consumes, w means the bandwidth of Resource Block, h _d,imean same group of D2D centering emission user and receive the channel gain between the user, p _{i, k, i}mean the transmitting power to the phone user of shared resource piece with one group of D2D, h _k,ichannel gain between the phone user of the shared same Resource Block of expression and the reception user of D2D centering, σ ²the variance that means white Gaussian noise;

(2) if x _i,jget definite value, just removed D2D in former optimization problem between coupling, be about to target function and be divided into two-layer independently optimization problem, wherein the ground floor optimization problem is Power Control Problem, second layer optimization problem is resource allocation problem;

(3), in the ground floor optimization problem, every group of D2D is to the efficiency function U (p on fixed resource _i,j) be expressed as:

$U\left(p_{i,j}\right)=\frac{R\left(p_{i,j}\right)}{p_{i,j}+P_C}=\frac{w\·{\log }_2(1+\frac{p_{i,j}\·h_{i,i}}{p_{C,k,i}\·h_{k,i}+{\mathrm{\σ}}^2})}{p_{i,j}+P_C},\∀i,\∀j---\left(2\right)$

This efficiency function has and successively decreases or first increase progressively the character of successively decreasing afterwards, and every group of D2D is to adopting separately advance and retreat method and Fibonacci method to try to achieve optimal solution separately;

(4) in second layer optimization problem, adopt heuristic resource allocation algorithm to carry out the resource distribution, determine that every group of D2D is to multiplexing resource.

In described step (4), the Mathematical Modeling of second layer optimization problem is:

$\max \underset{i=1}{\overset{N_d}{\mathrm{\Σ}}}\underset{j=1}{\overset{M^{\′}}{\mathrm{\Σ}}}{x}_{i,j}U\left(p_{i,j}^{*}\right)---\left(3\right)$

This Mathematical Modeling comprises following constraints:

$\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{x}_{i,j}=1,\∀i$

$\underset{i=1}{\overset{N_d}{\mathrm{\Σ}}}{x}_{i,j}\≤1,\∀j$

$x_{i,j}\∈\left\{\mathrm{0,1}\right\},\∀i,\∀j$

Wherein:

mean resulting optimum efficiency value in the ground floor optimization problem, utilize the result of ground floor optimization to adopt heuristic resource allocation algorithm to carry out the resource distribution, specifically comprise the steps:

4a). by every group of D2D to the optimum efficiency U (p on each available resources _i,j) sorted from big to small;

4b). first allow every group of D2D all take and can imitate U (p _i,j) maximum resource;

4c). find out resource and the D2D couple of conflict;

4d). resource and the D2D centering of conflict, calculate every group of D2C to adopting efficiency U (p _i,j) efficiency loss that the resource of taking second place causes, the resource of conflict is distributed to efficiency and lose the resource that maximum D2D takes second place to multiplexing efficiency to all the other D2D;

4e). repeat 4c)～4d), until D2D is to the not conflict of multiplexing resource.

Always there is a unique through-put power p of global optimum for formula (2) _i,jmake U (p _i,j) reaching maximum, proof procedure is (will use the concept of concavity) as follows in proof procedure:

Definition: one by n tie up DUAL PROBLEMS OF VECTOR MAPPING in real number convex set D become the function f of a real number be intend recessed, if for x arbitrarily ₁, x ₂∈ D and x ₁≠ x ₂have:

f(λx ₁+(1-λ)x ₂)>min{f(x ₁),f(x ₂)}

Wherein, 0<λ<1; At first can be in the hope of R (p _i,j) second dervative

wherein

so known R (p _i,j) about p _i,ja strict concave function, definition U (p _i,j) the superlevel collection as follows:

S _β={p _i,j>0|U(p _i,j)≥β}

If for any real number β, S _βa strict convex set, U (p _i,j) about p _i,jit is a strictly quasi-concave function; There is no some S when β>=0 on border when β<0 _β={ p _i,j0| β (p _i,j+ P _{c_ave})-R _i(p _i,j)≤0}; Because R is (p _i,j) about p _i,jstrict concave function, S _βabout p _i,jit is Strict Convex; This has just proved U (p _i,j) be about p _i,jstrictly quasi-concave function; U (p again _i,j) first derivative as follows:

$\frac{\mathrm{dU}\left(p_{i,j}\right)}{{\mathrm{dp}}_{i,j}}=w\&CenterDot;[\frac{y_i+y_c}{(1+y_i)\ln 2}-{\log }_2(1+y_i)]/{(p_{i,j}+P_C)}^2=\mathrm{\&theta;}\left(p_{i,j}\right)/{(p_{i,j}+P_C)}^2$

Wherein $y_c=\frac{P_C\&CenterDot;h_{i,i}}{p_{C,k,i}\&CenterDot;h_{k,i}+{\mathrm{\&sigma;}}^2},$ θ (p _i,j) first derivative be ${\mathrm{\&theta;}}^{\&prime;}\left(p_{i,j}\right)=-\frac{\mathrm{\&lambda;}(y_i+y_c)}{{(1+y_i)}^2\ln 2}<0,$ So θ (p _i,j) be monotone decreasing;

obvious, (1 °) when

the time, U (p _i,j) be first monotonic increase monotone decreasing again; (2 °) when

u(p _i,j) be monotone decreasing, so U (p _i,j) at p _i,j=p _initialpoint is obtained maximum, so certainly exist a unique through-put power p of global optimum _i,jmake U (p _i,j) reach maximum.

Beneficial effect: the high energy efficiency method for optimizing resources based on advance and retreat method and Fibonacci method provided by the invention, set up under guaranteeing that every group of D2D is to the optimum of efficiency on shared frequency spectrum resource prerequisite, all D2D users' Mathematical Modeling, and the complicated optimum problem of former coupling has been resolved into to the bilevel optimization problem, bring great convenience for solving; When considering D2D user self efficiency, allow every group of D2D user all be operated on its efficiency optimum point; When considering to introduce every group of corresponding efficiency of D2D user, also taken into account the efficiency of whole D2D system, and made whole efficiency optimum by heuristic resource allocation algorithm.

The accompanying drawing explanation

Fig. 1 is principle flow chart of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is further described.

Be illustrated in figure 1 a kind of high energy efficiency method for optimizing resources based on advance and retreat method and Fibonacci method, comprise the steps: in simple terms

1) every group of D2D be to perception interference to it from phone user on different resource respectively, and select the resource that interference power is less than certain threshold value, as feasible set of resources;

2) every group of D2D be to first by the advance and retreat method, obtaining the interval that comprises optimal power point respectively, then obtain its efficiency optimum point (being transmitting power) and corresponding efficiency value on feasible set of resources by Fibonacci method;

3) every group of D2D user by it efficiency optimum point on each feasible set of resources and corresponding efficiency value pass to base station.

4) base station adopts heuristic resource allocation algorithm finally to determine every group of resource that D2D user is multiplexing.

The specific implementation process of the method is as follows:

(1) set up the target function of efficiency, suc as formula (1)

$\max U_{\mathrm{EE}}=\underset{i=1}{\overset{N_d}{\mathrm{\&Sigma;}}}\frac{\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{i,j}\&CenterDot;R\left(p_{i,j}\right)}{\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{i,j}\&CenterDot;p_{i,j}+P_C}---\left(1\right)$

This target function comprises following constraints:

1. every group of minimum transmission rate request that D2D is right, minimum transmission rate can not be less than γ _i, the minimum transmission rate that D2D on the same group is not right can be different, to meet business need:

$R\left(p_{i,j}\right)\&GreaterEqual;{\mathrm{\&gamma;}}_i,\&ForAll;i,\&ForAll;j$

2. must be less than certain value τ to the phone user that shares same resource block to two D2D users' of this group D2D centering interference power with one group of D2D, the interference of bearing due to the reception user is larger, generally can think that the interference power to receiving the user must be less than certain value τ:

$p_{I,k,i}\&CenterDot;h_{k,i}\&le;\mathrm{\&tau;},{\&ForAll;x}_{i,j}=1$

3. x _i,jget 1 expression i group D2D multiplexing to selecting j Resource Block to carry out, x _i,jget 0 expression i group D2D to not selecting j Resource Block to carry out multiplexing:

$x_{i,j}\&Element;\left\{\mathrm{0,1}\right\},\&ForAll;i,\&ForAll;j$

4. every group of D2D is to Resource Block that can and can only a multiplexing phone user:

$\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{i,j}=1,\&ForAll;i$

5. each phone user's Resource Block at most can only be by one group of D2D to multiplexing:

$\underset{i=1}{\overset{N_d}{\mathrm{\&Sigma;}}}{x}_{i,j}\&le;1,\&ForAll;j$

6. D2D user's maximum transmission power limits:

$0\&le;p_{i,j}\&le;p_{\max },\&ForAll;i,\&ForAll;j$

Every group of D2D centering comprises two D2D users, and one of them is for receiving the user, and another is for sending the user;

Wherein: N _dmean the right group number of D2D, M means the number of allowable resource piece, and i means i group D2D couple, and j means j Resource Block, and k means the sequence number to the phone user of multiplexing same resource block with i group D2D; U _eEmean the efficiency sum that all D2D are right; $R\left(p_{i,j}\right)=w\&CenterDot;{\log }_2(1+\frac{p_{i,j}\&CenterDot;h_{D,i}}{p_{I,k,i}\&CenterDot;h_{k,i}+{\mathrm{\&sigma;}}^2}),$ Speed while meaning i group D2D to multiplexing j Resource Block; p _i,jmean that i group D2D is to the through-put power on j Resource Block, P _cmean the power (not being subject to the impact of D2D on through-put power) that on mobile terminal, circuit consumes, w means the bandwidth of Resource Block, h _d,imean same group of D2D centering emission user and receive the channel gain between the user, p _{i, k, i}mean the transmitting power to the phone user of shared resource piece with one group of D2D, h _k,ichannel gain between the phone user of the shared same Resource Block of expression and the reception user of D2D centering, σ ²the variance that means white Gaussian noise;

(2) if x _i,jget definite value, just removed D2D in former optimization problem between coupling, be about to target function and be divided into two-layer independently optimization problem, wherein the ground floor optimization problem is Power Control Problem, second layer optimization problem is resource allocation problem;

(3), in the ground floor optimization problem, every group of D2D is to the efficiency function U (p on fixed resource _i,j) be expressed as:

$U\left(p_{i,j}\right)=\frac{R\left(p_{i,j}\right)}{p_{i,j}+P_C}=\frac{w\&CenterDot;{\log }_2(1+\frac{p_{i,j}\&CenterDot;h_{i,i}}{p_{C,k,i}\&CenterDot;h_{k,i}+{\mathrm{\&sigma;}}^2})}{p_{i,j}+P_C},\&ForAll;i,\&ForAll;j---\left(2\right)$

This efficiency function has and successively decreases or first increase progressively the character of successively decreasing afterwards, and every group of D2D is to adopting separately advance and retreat method and Fibonacci method to try to achieve optimal solution separately;

(4) in second layer optimization problem, adopt heuristic resource allocation algorithm to carry out the resource distribution, determine that every group of D2D is to multiplexing resource.

In described step (4), the Mathematical Modeling of second layer optimization problem is:

$\max \underset{i=1}{\overset{N_d}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{M^{\&prime;}}{\mathrm{\&Sigma;}}}{x}_{i,j}U\left(p_{i,j}^{*}\right)---\left(3\right)$

This Mathematical Modeling comprises following constraints:

$\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{i,j}=1,\&ForAll;i$

$\underset{i=1}{\overset{N_d}{\mathrm{\&Sigma;}}}{x}_{i,j}\&le;1,\&ForAll;j$

$x_{i,j}\&Element;\left\{\mathrm{0,1}\right\},\&ForAll;i,\&ForAll;j$

Wherein:

mean resulting optimum efficiency value in the ground floor optimization problem, utilize the result of ground floor optimization to adopt heuristic resource allocation algorithm to carry out the resource distribution, specifically comprise the steps:

4a). by every group of D2D to the optimum efficiency U (p on each available resources _i,j) sorted from big to small;

4b). first allow every group of D2D all take and can imitate U (p _i,j) maximum resource;

4c). find out resource and the D2D couple of conflict;

4d). resource and the D2D centering of conflict, calculate every group of D2C to adopting efficiency U (p _i,j) efficiency loss that the resource of taking second place causes, the resource of conflict is distributed to efficiency and lose the resource that maximum D2D takes second place to multiplexing efficiency to all the other D2D;

4e). repeat 4c)～4d), until D2D is to the not conflict of multiplexing resource.

The above is only the preferred embodiment of the present invention; be noted that for those skilled in the art; under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (2)

1. the high energy efficiency method for optimizing resources based on advance and retreat method and Fibonacci method, is characterized in that: comprise the steps:

(1) set up the target function of efficiency, suc as formula (1)

$\max U_{\mathrm{EE}}=\underset{i=1}{\overset{N_d}{\mathrm{\&Sigma;}}}\frac{\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{i,j}\&CenterDot;R\left(p_{i,j}\right)}{\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{i,j}\&CenterDot;p_{i,j}+P_C}---\left(1\right)$

This target function comprises following constraints:

1. every group of minimum transmission rate request that D2D is right, minimum transmission rate can not be less than γ _i, the minimum transmission rate that D2D on the same group is not right can be different:

$R\left(p_{i,j}\right)\&GreaterEqual;{\mathrm{\&gamma;}}_i,\&ForAll;i,\&ForAll;j$

2. must be less than certain value τ to the phone user that shares same resource block to two D2D users' of this group D2D centering interference power with one group of D2D:

$p_{I,k,i}\&CenterDot;h_{k,i}\&le;\mathrm{\&tau;},{\&ForAll;x}_{i,j}=1$

3. x _i,jget 1 expression i group D2D multiplexing to selecting j Resource Block to carry out, x _i,jget 0 expression i group D2D to not selecting j Resource Block to carry out multiplexing:

$x_{i,j}\&Element;\left\{\mathrm{0,1}\right\},\&ForAll;i,\&ForAll;j$

4. every group of D2D is to Resource Block that can and can only a multiplexing phone user:

$\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{i,j}=1,\&ForAll;i$

5. each phone user's Resource Block at most can only be by one group of D2D to multiplexing:

$\underset{i=1}{\overset{N_d}{\mathrm{\&Sigma;}}}{x}_{i,j}\&le;1,\&ForAll;j$

6. D2D user's maximum transmission power limits

$0\&le;p_{i,j}\&le;p_{\max },\&ForAll;i,\&ForAll;j$

Every group of D2D centering comprises two D2D users, and one of them is for receiving the user, and another is for sending the user;

Wherein: N _dmean the right group number of D2D, M means the number of allowable resource piece, and i means i group D2D couple, and j means j Resource Block, and k means the sequence number to the phone user of multiplexing same resource block with i group D2D; U _eEmean the efficiency sum that all D2D are right; $R\left(p_{i,j}\right)=w\&CenterDot;{\log }_2(1+\frac{p_{i,j}\&CenterDot;h_{D,i}}{p_{I,k,i}\&CenterDot;h_{k,i}+{\mathrm{\&sigma;}}^2}),$ Speed while meaning i group D2D to multiplexing j Resource Block; p _i,jmean that i group D2D is to the through-put power on j Resource Block, P _cmean the power that on mobile terminal, circuit consumes, w means the bandwidth of Resource Block, h _d,imean same group of D2D centering emission user and receive the channel gain between the user, p _{i, k, i}mean the transmitting power to the phone user of shared resource piece with one group of D2D, h _k,ichannel gain between the phone user of the shared same Resource Block of expression and the reception user of D2D centering, σ ²the variance that means white Gaussian noise;

(2) if x _i,jget definite value, just removed D2D in former optimization problem between coupling, be about to target function and be divided into two-layer independently optimization problem, wherein the ground floor optimization problem is Power Control Problem, second layer optimization problem is resource allocation problem;

(3), in the ground floor optimization problem, every group of D2D is to the efficiency function U (p on fixed resource _i,j) be expressed as:

$U\left(p_{i,j}\right)=\frac{R\left(p_{i,j}\right)}{p_{i,j}+P_C}=\frac{w\&CenterDot;{\log }_2(1+\frac{p_{i,j}\&CenterDot;h_{i,i}}{p_{C,k,i}\&CenterDot;h_{k,i}+{\mathrm{\&sigma;}}^2})}{p_{i,j}+P_C},\&ForAll;i,\&ForAll;j---\left(2\right)$

This efficiency function has and successively decreases or first increase progressively the character of successively decreasing afterwards, and every group of D2D is to adopting separately advance and retreat method and Fibonacci method to try to achieve optimal solution separately;

(4) in second layer optimization problem, adopt heuristic resource allocation algorithm to carry out the resource distribution, determine that every group of D2D is to multiplexing resource.

2. the high energy efficiency method for optimizing resources based on advance and retreat method and Fibonacci method according to claim 1, it is characterized in that: in described step (4), the Mathematical Modeling of second layer optimization problem is:

$\max \underset{i=1}{\overset{N_d}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{M^{\&prime;}}{\mathrm{\&Sigma;}}}{x}_{i,j}U\left(p_{i,j}^{*}\right)---\left(3\right)$

This Mathematical Modeling comprises following constraints:

$\underset{j=1}{\overset{M}{\mathrm{\&Sigma;}}}{x}_{i,j}=1,\&ForAll;i$

$\underset{i=1}{\overset{N_d}{\mathrm{\&Sigma;}}}{x}_{i,j}\&le;1,\&ForAll;j$

$x_{i,j}\&Element;\left\{\mathrm{0,1}\right\},\&ForAll;i,\&ForAll;j$

Wherein:

mean resulting optimum efficiency value in the ground floor optimization problem, utilize the result of ground floor optimization to adopt heuristic resource allocation algorithm to carry out the resource distribution, specifically comprise the steps:

4a). by every group of D2D to the optimum efficiency U (p on each available resources _i,j) sorted from big to small;

4b). first allow every group of D2D all take and can imitate U (p _i,j) maximum resource;

4c). find out resource and the D2D couple of conflict;

4d). resource and the D2D centering of conflict, calculate every group of D2C to adopting efficiency U (p _i,j) efficiency loss that the resource of taking second place causes, the resource of conflict is distributed to efficiency and lose the resource that maximum D2D takes second place to multiplexing efficiency to all the other D2D;

4e). repeat 4c)～4d), until D2D is to the not conflict of multiplexing resource.

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