CN102026201A - Game type selection-based method for realizing dynamic spectrum allocation - Google Patents

Abstract

The implementation method of dynamic spectrum allocation based on game type selection. With the development of wireless communication technology, the traditional fixed spectrum allocation method leads to waste of resources and low spectrum utilization, which has become a key factor restricting the further development of wireless communication networks. The dynamic spectrum allocation technology based on cognitive radio is considered to be a key technology that can effectively solve the above problems. In the present invention, by comparing the returns of the complete and perfect dynamic game and the Nash negotiation, the cognitive base station and the secondary user can flexibly and fairly choose their respective best strategies, that is, the optimal spectrum unit quotation and spectrum purchase amount. At the same time, in order to realize the selection operation of both parties, a simple spectrum access process is designed, which is compatible with the traditional mobile call access process. The invention can effectively increase the return of cognitive base stations and secondary users, and promote spectrum utilization.

Description

The implementation method of the dynamic frequency spectrum deployment of selecting based on game types

Technical field

The invention belongs to the frequency spectrum resource management method for designing of the cognition network of wireless communication technology field, relate in particular to a kind of implementation method of the dynamic frequency spectrum deployment of selecting based on game types.

Background technology

Along with the sustainable growth of radio communication service demand, the frequency range that is suitable for radio communication service has at present become very crowded, and regulator has realized that traditional fixed frequency spectrum mode is unusual poor efficiency.Dynamic frequency spectrum deployment based on cognitive radio allows secondary user's (unauthorized user) under the prerequisite of not disturbing naive user (authorized user) communication, dynamically inserts the idle frequency range of naive user in the mode of consulting and select a good opportunity, thereby improves the availability of frequency spectrum.Therefore, dynamic frequency spectrum deployment is considered to alleviate the wireless frequency spectrum shortage, improves one of key technology of the availability of frequency spectrum.

In cognition wireless network, subscriber equipment equipment has certain cognitive ability, and the frequency spectrum decision-making of unique user can be subjected to the influence of self other users' decision-making; Simultaneously, user's decision-making is autonomous.Therefore, game theoretical model is the common tool of research trends spectrum allocation may, and many scholars have launched research to this.Zhu has provided the summary based on game theoretic dynamic frequency spectrum deployment research.Zhao etc. utilize game theory that cognition network is carried out Performance Evaluation, and have provided measure and utility function.Be the QoS of assurance PU and the BER requirement of SU, Attar etc. have proposed a kind of distribution frame based on cooperative game and Na Shi negotiation.At user's selfish characteristic, Wang etc. have proposed the Mechanism Design problem, and making tells the truth becomes player's best strategy.Wu etc. have proposed a kind of repeated game model based on punishment, make the user that the real information of motivation exchange oneself be arranged.Frequency spectrum lease and secondary frequency spectrum trade market are the important kind that realizes dynamic frequency spectrum deployment.Jayaweera etc. have studied the dynamic spectrum lease problem that has realized heterogeneous network by the game of power control.In the secondary frequency spectrum marketing model of foundation such as Niyato, a plurality of PU launch non-cooperative game for winning SU.Mihaela etc. have utilized at random game theory analysis multiple centralized and distributed secondary frequency spectrum access market, and provided the optimal policy that can satisfy effectiveness and fairness tolerance target.Huang and Gandhi have analyzed the auction problem of game under the interference-limited constraint.

Existing research supposes that the game types of dynamic frequency spectrum deployment is constant more, and in fact, player's game types can be bidded and demand situation changes along with different in the spectrum allocation may process.The bid that can reduce oneself such as CRBS to be exchanging more spectrum requirement for, thereby improves the income of oneself.In this patent, we have studied also is the access request of cognitive base station in the face of multiple types of terminals equipment, how to improve the income of oneself, the spectrum utilization of encouraging the user simultaneously by man-to-man price game.Studies show that the base station can select game types to maximize the income of oneself according to the spectrum utilization ability of SU neatly, does not damage the income of SU simultaneously, and encourages the spectrum utilization of SU.The spectrum allocation may flow process that proposes can guarantee carrying out smoothly of game effectively, and with existing flow process compatibility.

Summary of the invention

The object of the present invention is to provide a kind of repayment that increases cognitive base station and secondary user's effectively, and promote the implementation method of the dynamic frequency spectrum deployment of selecting based on game types of spectrum utilization.

For achieving the above object, the technical solution used in the present invention is: in communication scenes, cognitive base station (cognitive radio base station, CRBS) and secondary user's (secondary users, behavior SU) had with the next stage:

(1) CRBS proposes frequency spectrum quotation w;

(2) SU observes (and acceptance) w, selects frequency spectrum use amount L subsequently;

(3) repayment of CRBS and SU be respectively U (w, L) and π (w, L);

For any quotation w that CRBS in the phase I proposes, SU decides optimum spectrum requirement L by maximizing its repayment in second stage ^*(w), promptly

$\underset{L\≥0}{\max }\mathrm{\π}(w,L)=\underset{L\≥0}{\max }\{R\left(L\right)-\mathrm{wL}\}$

Try to achieve optimum spectrum requirement L ^*(w);

Backstepping is to the phase I, and CRBS selects w ^*Make U (w ^*, L ^*(w ^*)) reaching maximization, this quotation is called as the optimum quotation per unit under the dynamic game, is designated as separating of following formula:

$\underset{w\≥0}{\max }U(w,L^{*}\left(w\right))$

If launch to receive assorted negotiation with regard to a frequency spectrum use between CRBS and the SU, if both sides can not reach an agreement, then both sides' utility level all is 0; If both sides reach an agreement, the utility level of CRBS is u ₁, the utility level of SU is π ₁, corresponding optimization aim is:

$\underset{w,L}{\max }U(w,L)\mathrm{\π}(w,L)$

Get the CRBS optimal spectrum quotation per unit w of this moment ^BWith SU optimal spectrum purchase volume L ^B

The dynamic frequency spectrum deployment method is as follows:

(1) CRBS periodically announce oneself the repayment function U (w, L), SU in the networking initialization procedure, announce oneself repayment function π (w, L);

(2) CRBS proposes the frequency spectrum w that initially offers ^*, this quotation is the optimum bid of the CRBS in the conventional dynamic game;

(3) SU observes w ^*, and at oneself dynamic optimal spectrum use amount L ^*With receive assorted bargaining solution frequency spectrum use amount L ^BIn select one and report CRBS;

(4) CRBS is that SU assigns corresponding frequency spectrum quantity, but contract quoting is at L ^*Be w ^*, at L ^BBe w ^B, SU will offer as agreed and repay the frequency spectrum cost of use.

The present invention is by the repayment of more complete and perfect dynamic game and Na Shi negotiation, and cognitive base station and secondary user's can be selected optimal strategy separately, promptly optimum frequency spectrum quotation per unit and frequency spectrum purchase volume flexibly liberally.Simultaneously, for realizing both sides' selection operation, designed a kind of simple frequency spectrum access process, with traditional mobile calls access process compatibility.Can increase the repayment of cognitive base station and secondary user's effectively, and promote spectrum utilization.

Description of drawings

Fig. 1 is the spectrum allocation may figure of the cognitive sub-district of multiple access;

Fig. 2 is the poor efficiency figure of dynamic game equilibrium;

Fig. 3 is the situation of change (DG: dynamic game of the repayment function of CRBS and SU with α; NB: receive assorted negotiation);

Fig. 4 is that α changes the influence (DG: dynamic game to SU frequency spectrum purchase volume; NB: receive assorted negotiation);

Fig. 5 is that α changes the influence (DG: dynamic game to CRBS frequency spectrum quotation per unit; NB: receive assorted negotiation).

Embodiment

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

Consider the scene of single cognitive multiple access sub-district, as shown in Figure 1.Cognitive base station has the usable spectrum that obtains in secondary frequency spectrum marketing, and can reshuffle flexibly self with and the terminal communication of polytype (as types such as WCDMA, CDMA2000EV-DO).Dissimilar users (SU) needing from the communication of acquisition frequency spectrum in base station with oneself to thirst in the sub-district.Because the spectrum opportunities of CRBS is paid acquisition,, SU pays a price so being necessary for the frequency spectrum use of oneself.CRBS proposes the unit frequency spectrum and uses price w, has used the SU of L unit's frequency spectrum to need to pay expense wL to CRBS.

The repayment function of supposing CRBS be U (w, L).Obviously Be that U is the increasing function of quotation w and use amount L.The repayment function of SU is that (w, L)=R (L)-wL, wherein R (L) is the communication revenue function of SU to π.Obviously, income is big more more at most for the frequency spectrum that SU uses, but the marginal benefit that its frequency spectrum uses is then more and more littler.Therefore, R (L) is the increasing function of L and is concave function.R ' (0)=∞, R ' (∞)=0, promptly R ' (L) ∈ [0, ∞).

In the communication scenes of routine, the behavior of CRBS and SU had with the next stage:

(1) CRBS proposes frequency spectrum quotation w;

(2) SU observes (and acceptance) w, selects frequency spectrum use amount L subsequently;

(3) repayment of CRBS and SU be respectively U (w, L) and π (w, L).

Therefore, CRBS and SU all are faced with and how obtain maximum repayment in the frequency spectrum transaction.

For SU, it is clear know CRBS repayment U (w L) is equal to the in-and-out price difference of frequency spectrum, promptly has:

U(w，L)＝(w-w ₀)L

W wherein ₀Be CRBS per unit frequency spectrum secondary market transaction cost.Obviously, w 〉=w ₀〉=0.

CRBS can be configured to different mode and communicate by letter with SU, for example from the WCDMA mode switch be the CDMA2000 pattern to satisfy the access request of certain EV-DO type SU, the clear complete characteristic of knowing the CDMA2000 terminal of CRBS then, therefore, it also knows repayment function π (w, structure L) of SU.Simply, order:

π(w，L)＝R(L)-wL

$R\left(L\right)=\sqrt{L}$

The repayment function (net profit) of SU equals frequency spectrum and uses income R (L) to deduct cost of use wL.It is the increasing function of L that the frequency spectrum of SU uses income, but its growth slows down gradually.This can explain like this: have more frequency spectrum, SU just can carry out more business (as video calling) or improve the professional income (as reducing power consumption) that obtains; But, L hour, the frequency spectrum purchase volume can not satisfy the business of SU carries out, and increases purchase volume and can improve business income significantly; When L was big, the traffic load of SU was saturated substantially, increased purchase volume and promoted very little to improving business income.

Because the version of repayment function is known to the both sides before transaction beginning and CRBS and SU all can observe the other side's action, sees that according to game theoretic viewpoint this communication scenes is a complete and perfect dynamic game.Player 1 is CRBS, and its strategic space is { to propose frequency spectrum quotation w}; Player 2 is SU, and its strategic space is { decision frequency spectrum use amount L}.

For complete and perfect dynamic game, can use reverse induction to find the solution.

For any quotation w that CRBS in the phase I proposes, SU decides optimum spectrum requirement L by maximizing its repayment in second stage ^*(w), promptly

$\underset{L\≥0}{\max }\mathrm{\π}(w,L)=\underset{L\≥0}{\max }\{R\left(L\right)-\mathrm{wL}\}$

By first-order condition R ' (L)=w solves:

$L^{*}=L^{*}\left(w\right)=\frac{1}{{4w}^2}$

Backstepping is to the phase I now, and CRBS selects then w ^*Make U (w ^*, L ^*(w ^*)) reach maximization, promptly CRBS in the target of phase I is

$\underset{w\≥0}{\max }U(w,L^{*}\left(w\right))$

Can obtain best CRBS quotation and corresponding SU use amount is:

$\left\{\begin{array}{c}{w}^{*}=2w_0\\ L^{*}=\frac{1}{16w_0^2}\end{array}\right.$

Then after complete and perfect information game, both sides' income is:

$\left\{\begin{array}{c}U=\frac{1}{16w_0}\\ \mathrm{\π}=\frac{1}{8w_0}\end{array}\right.$

Fig. 2 has provided the picture specification of above solution procedure.U ₂And U ₀Be the indifference curve of CRBS, on the indifference curve all each points (w, L) combination brings identical repayment to CRBS, obviously U ₂＞U ₀π ₂And π ₀Be the indifference curve (waiting acknowledge line) of SU, when using identical frequency spectrum quantity (income is identical), the quotation that the upper curve correspondence is bigger, obviously π ₂＞π ₀L ^*(w) be the optimal spectrum purchase volume of the different quotations of SU reply CRBS, therefore, curve L ^*(w) and the point of contact of CRBS indifference curve be exactly the equilibrium point of game.

Obviously, if the combined spot of w and L is arranged in Fig. 2 dash area, promptly the quotation of CRBS is than w ^*Reduce, the frequency spectrum purchase volume of SU is than L ^*(w ^*) increase, then the repayment of CRBS and SU all can improve simultaneously, and just new combined spot is that Pareto is effective with respect to the equilibrium point.

Carrying out unlimited repeated game can be so that the game both sides selects effectively strategy combination of Pareto, and still, the probability that the mobility of SU and professional bursting property make unlimited repeated game take place is very little.A more real model is to receive assorted bargaining model, also is to use the expansion consultation with regard to a frequency spectrum between CRBS and the SU, if both sides can not reach an agreement, then both sides' utility level all is 0; If both sides reach an agreement, the utility level of CRBS is u ₁, the utility level of SU is π ₁Corresponding optimization aim is:

$\underset{w,L}{\max }U(w,L)\mathrm{\π}(w,L)$

In view of U (w, L) and π (w L) is continuous function while bounded on the domain of definition, so must there be optimal solution in the problems referred to above, and the assorted negotiation of promptly receiving can obtain (u ₁, π ₁), the both sides that then participate in the frequency spectrum transaction have two selections, the dynamic game or the assorted negotiation of receiving.

Find the solution this optimization problem, can be at point

$\left\{\begin{array}{c}{w}_B=\frac{3}{2}{w}_0\\ L_B=\frac{1}{4w_0^2}\end{array}\right.$

Obtain maximum:

$\left\{\begin{array}{c}{U}_B=\frac{1}{8w_0}\\ {\mathrm{\π}}_B=\frac{1}{8w_0}\end{array}\right.$

The cotype dynamic game compares, and both sides' effectiveness that the assorted negotiation of obviously receiving obtains is better than the effectiveness of dynamic game.This mainly is the quotation that reduces oneself by CRBS, has encouraged the frequency spectrum of SU to use, thereby improved the repayment of oneself under the prerequisite of not damaging the SU repayment.

The Ruo Nashi negotiation is more excellent separating, and then CRBS or SU wish participating in this negotiation.Wish that as CRBS SU can improve the frequency spectrum use amount when oneself reduces quotation.But the analyzing examples of front shows, this moment, SU can not make a profit the assorted negotiation from receiving, and therefore, its strategy can be to keep original purchase volume, and this can damage the interests of CRBS.Therefore, need introducing certain constraint makes both sides participate under the prerequisite of not damaging number one to receive in the assorted negotiation.

For this reason, introduce new spectrum allocation may flow process:

(1) CRBS periodically announce oneself the repayment function U (w, L), SU in the networking initialization procedure, announce oneself repayment function π (w, L);

(2) CRBS proposes the frequency spectrum w that initially offers ^*

(3) SU observes w ^*, calculate and at oneself dynamic optimal spectrum use amount L ^*With receive assorted bargaining solution frequency spectrum use amount L ^BIn select one and report CRBS;

(4) CRBS is that SU assigns corresponding frequency spectrum quantity, but contract quoting is at L ^*Be w ^*, at L ^BBe w ^BSU will offer as agreed and repay the frequency spectrum cost of use.

The frequency spectrum that SU uses is that CRBS distributes, so its purchase volume need be through the affirmation of CRBS.As provide the long-term communication serving base station can be for the profit of once transaction wrong valuation (demand L ^BThe time by the quotation w ^*Charge) or the wrong frequency spectrum quantity of paying, can damage oneself prestige like this.Therefore, it is feasible receiving assorted negotiation.

Analyze now the optimal policy of CRBS and SU under general situation.Both sides' repayment function is as follows:

U(w，L)＝(w-w ₀)L

π(w，L)＝R(L)-wL

R(L)＝L ^α?α∈(0，1)

Be cost price w ₀Be variable, the income of SU also is variable.Then in dynamic game, quotation and the frequency spectrum purchase volume that can obtain the best are:

$\left\{\begin{array}{c}{w}^{*}=\frac{w_0}{\mathrm{\α}}\\ L^{*}={\left(\frac{w_0}{{\mathrm{\α}}^2}\right)}^{\frac{1}{\mathrm{\α}-1}}\end{array}\right.$

Corresponding both sides' repayment this moment is:

$\left\{\begin{array}{c}{U}_0=(\mathrm{\α}-{\mathrm{\α}}^2){\left(\frac{w_0}{{\mathrm{\α}}^2}\right)}^{\frac{\mathrm{\α}}{\mathrm{\α}-1}}\\ {\mathrm{\π}}_0=(1-\mathrm{\α}){\left(\frac{w_0}{{\mathrm{\α}}^2}\right)}^{\frac{\mathrm{\α}}{\mathrm{\α}-1}}\end{array}\right.$

Receiving assorted negotiation back best quotation and frequency spectrum purchase volume be:

$\left\{\begin{array}{c}{w}_B=\frac{w_0}{\mathrm{\α}}\frac{\mathrm{\α}+1}{2}\\ L_B{=\left(\frac{w_0}{\mathrm{\α}}\right)}^{\frac{1}{\mathrm{\α}-1}}\end{array}\right.$

Corresponding both sides' repayment this moment is:

$\left\{\begin{array}{c}{U}_B=\frac{1-\mathrm{\α}}{2}{\left(\frac{w_0}{\mathrm{\α}}\right)}^{\frac{\mathrm{\α}}{\mathrm{\α}-1}}\\ {\mathrm{\π}}_B=\frac{1-\mathrm{\α}}{2}{\left(\frac{w_0}{\mathrm{\α}}\right)}^{\frac{\mathrm{\α}}{\mathrm{\α}-1}}\end{array}\right.$

From top formula as can be seen, no matter be dynamic game or receive assorted negotiation, given both sides' repayment function, it is very little that the player makes more required amount of calculation.Therefore, the selection of this spectrum allocation may strategy can be carried out fast in existing type equipment and base station survey.

Can prove that for SU the superiority of assorted negotiation received depends on the parameter alpha in the revenue function.And CRBS always wishes to receive assorted negotiation.Less cost price can encourage frequency spectrum to use simultaneously.This provides an instrument that the regulation and control frequency spectrum uses for frequency spectrum supervision mandate department.

Utilize Matlab software that the conclusion that obtains is previously carried out the system emulation checking.The cost price that Fig. 3 has provided at CRBS is 1 o'clock, and the variation of α is to the influence of CRBS and the final repayment of SU.As can be seen, when α＜0.5, SU tends to dynamic game, and in α＞0.5 o'clock, the assorted negotiation that participates in receiving will bring more income for SU.This is consistent with the conclusion in 3.4.For CRBS, the repayment of negotiation (note the repayment curve of this moment and SU negotiation repayment curve overlap) always be better than dynamic game.

The cost price that Fig. 4 and Fig. 5 have provided respectively at CRBS is 1 o'clock, and the variation of α is to the influence of SU frequency spectrum purchase volume and CRBS quotation per unit.As can be seen, the quotation the when quotation of CRBS when participating in receiving assorted negotiation always is lower than dynamic game, corresponding therewith is, SU always is higher than the purchase volume of dynamic game receiving frequency spectrum purchase volume after the assorted negotiation.This has verified that the analysis conclusion of Fig. 2: CRBS can reduce bid and use more frequency spectrum to stimulate SU, thereby improves the repayment (referring to Fig. 3) of self.

Claims (1)

1. the implementation method of the dynamic frequency spectrum deployment of selecting based on game types is characterized in that:

In communication scenes, cognitive base station (cognitive radio base station, CRBS) and secondary user's (secondary users, behavior SU) had with the next stage:

(1) CRBS proposes frequency spectrum quotation w;

(2) SU observes (and acceptance) w, selects frequency spectrum use amount L subsequently;

(3) repayment of CRBS and SU be respectively U (w, L) and π (w, L);

For any quotation w that CRBS in the phase I proposes, SU decides optimum spectrum requirement L by maximizing its repayment in second stage ^*(w), promptly

$\underset{L\≥0}{\max }\mathrm{\π}(w,L)=\underset{L\≥0}{\max }\{R\left(L\right)-\mathrm{wL}\}$

Try to achieve optimum spectrum requirement L ^*(w);

Backstepping is to the phase I, and CRBS selects w ^*Make U (w ^*, L ^*(w ^*)) reaching maximization, this quotation is called as the optimum quotation per unit under the dynamic game, is designated as separating of following formula:

$\underset{w\≥0}{\max }U(w,L^{*}\left(w\right))$

If launch to receive assorted negotiation with regard to a frequency spectrum use between CRBS and the SU, if both sides can not reach an agreement, then both sides' utility level all is 0; If both sides reach an agreement, the utility level of CRBS is u ₁, the utility level of SU is π ₁, corresponding optimization aim is:

$\underset{w,L}{\max }U(w,L)\mathrm{\π}(w,L)$

Get the CRBS optimal spectrum quotation per unit w of this moment ^BWith SU optimal spectrum purchase volume L ^B

The dynamic frequency spectrum deployment method is as follows:

(1) CRBS periodically announce oneself the repayment function U (w, L), SU in the networking initialization procedure, announce oneself repayment function π (w, L);

(2) CRBS proposes the frequency spectrum w that initially offers ^*, this quotation is the optimum bid of the CRBS in the conventional dynamic game;

(3) SU observes w ^*, and at oneself dynamic optimal spectrum use amount L ^*With receive assorted bargaining solution frequency spectrum use amount L ^BIn select one and report CRBS;

(4) CRBS is that SU assigns corresponding frequency spectrum quantity, but contract quoting is at L ^*Be w ^*, at L ^BBe w ^B, SU will offer as agreed and repay the frequency spectrum cost of use.

Images