CN104780567A - Satellite network flow control method - Google Patents

Abstract

An embodiment of the invention provides a satellite network flow control method. The method comprises steps as follows: determining a GEO satellite, the channel capacity of each LEO satellite and the channel bit error ratio threshold value allowed by a satellite system; if the sum of the channel capacity of all the LEO satellites is larger than the channel capacity of the GEO satellite, determining the data transmission rate of each LEO satellite with non-cooperative game equilibrium; controlling the satellite network flow according to the data transmission rate of each LEO satellite. With the adoption of the method, the data transmission rate of each LEO satellite is optimized, and the optimal system transmission performance is realized.

Description

A kind of satellite network flow control methods

Technical field

The embodiment of the present invention relates to radio transmission techniques field, particularly relates to a kind of satellite network flow control methods.

Background technology

Satellite communication wide coverage, does not limit by geographical conditions, in commercial communication, is that other means of communication can not be compared.At present, the application such as satellite television, broadcast, remote monitoring, video conference is more and more extensive.Especially emergency communication aspect, satellite communication have ground communication can not and advantage, be no matter in city, rural area, mountain area or desert, can satellite communication be realized.

LEO satellite has R&D cycle short, the feature such as launch cost is low, propagation delay time is little, obtains and apply more and more widely in meteorology, the hydrology, geological disaster, scientific experimentation etc.Especially in rescue and relief work, because satellite coverage is wide, not by the restriction of ground infrastructure, when the strong natural calamity of generation, other GCF ground communication facilities are destroyed, satellite communication is very necessary a kind of means of communication, in time the condition of a disaster can be conveyed to command centre, be convenient to rescue work and launch.Because LEO satellite orbit is low, shorter with the led to time of ground station, when satellite and ground station not visible time, mass data can only be kept on satellite, poor in timeliness, and a large amount of memory devices makes the load-carrying ability on star weaken.In order to reduce data transmission delay and the requirement to LEO satellite storage capacity, when LEO satellite and ground station not visible time will be forwarded to ground station by GEO satellite.

But, the transfer capability of GEO satellite is limited, when transfer capability more than GEO satellite of the transmission rate of many LEO satellites forwarding data simultaneously, because each LEO satellite is different to the channel quality of GEO satellite, if reduce each channel speed equably, for the channel that quality is lower, receiving terminal cannot receive valid data, waste limited channel resource, and the data of high-quality channel can not get timely transmission.

Summary of the invention

The embodiment of the present invention provides a kind of satellite network flow control methods, during with the transfer capability of the transmission rate overcoming in prior art many LEO satellites forwarding data simultaneously more than GEO satellite, and the problem that channel resource utilance is low.

The embodiment of the present invention provides a kind of satellite network flow control methods, comprising:

Determine the channel capacity of GEO satellite, each LEO satellite and the channel bit error rate threshold value of satellite system permission;

If the channel capacity sum of described each LEO satellite is greater than the channel capacity of described GEO satellite, then Nash Equilibrium is adopted to determine the message transmission rate of described each LEO satellite;

Message transmission rate according to described each LEO satellite controls satellite network flow.

Further, described determine GEO satellite, each LEO satellite channel capacity and the channel quality that allows of satellite system after, also comprise:

Judge GEO satellite, whether the channel quality of each LEO satellite meet the channel quality requirement of satellite system.

Further, described employing Nash Equilibrium determines the message transmission rate of each satellite, comprising:

Determine that the revenue function of single LEO satellite in the Nash Equilibrium based on satellite channel quality is:

$U\left(x_i\right)=\frac{{\left[x_i{(1-{\mathrm{Pe}}_i)}^{x_i}\right]}^{{\mathrm{\β}}_i}}{\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}}---\left(1\right)$

Wherein, described U (x _i) be the ratio of satellite channel throughput and data accumulation time delay, described x _ifor the transmission rate of user, described Pe _ifor LEO _ithe channel bit error rate of satellite, described c is GEO satellite channel capacity over the ground, described β _ifor balance coefficient, and β _i∈ (0,1];

Adopt nonlinear iteration that described revenue function is converted to formula

$f\left(x_i\right)=\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}---\left(2\right)$

To any x _imeet time, solve described formula (3),

$x_{i+1}=x_i-k\frac{f\left(x_i\right)}{f^{\′}\left(x_i\right)}=x_i-k\frac{\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}}{-\frac{{\mathrm{\β}}_i}{x_i^2}-\frac{1}{{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}^2}}---\left(3\right)$

Determine the message transmission rate of LEO satellite, wherein, described W (x _i) be the logarithmic form of formula (1), revenue function is converted to the throughput of LEO satellite transmission data and the difference of time delay.

The embodiment of the present invention determines the channel capacity of GEO satellite, each LEO satellite and the channel bit error rate threshold value of satellite system permission, thus when the channel capacity sum of each LEO satellite is greater than the channel capacity of GEO satellite, adopt Nash Equilibrium to determine the message transmission rate of each LEO satellite, and control satellite network flow according to the message transmission rate of described each LEO satellite.During the transfer capability of the transmission rate solving in prior art many LEO satellites forwarding data simultaneously more than GEO satellite, the problem that channel resource utilance is low.The embodiment of the present invention is applicable to the non-cooperation Nash game flow control based on channel quality of LEO-GEO-earth communication system, makes entire system income the highest, instead of merely change the flow of a certain LEO satellite by the flow control of each LEO satellite.Improve the channel resource utilance of system.

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 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 accompanying drawings.

Fig. 1 is satellite network flow control methods flow chart of the present invention;

Fig. 2 is satellite network flow control methods satellite flow structural representation of the present invention;

Fig. 3 is LEO satellite data transmission rate contrast figure in satellite network flow control methods simulation result of the present invention;

Fig. 4 is LEO satellite system revenue function contrast figure in satellite network flow control methods simulation result of the present invention;

Fig. 5 is another LEO satellite data transmission rate contrast figure in satellite network flow control methods simulation result of the present invention;

Fig. 6 is another LEO satellite system revenue function contrast figure in satellite network flow control methods simulation result of the present invention.

Embodiment

For making the object of the embodiment of the present invention, technical scheme and advantage clearly, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is 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.

Fig. 1 is satellite network flow control methods flow chart of the present invention, and as shown in Figure 1, the method for the present embodiment can comprise:

The channel bit error rate threshold value that step 101, the channel capacity determining GEO satellite, each LEO satellite and satellite system allow;

If the channel capacity sum of the described each LEO satellite of step 102 is greater than the channel capacity of described GEO satellite, then Nash Equilibrium is adopted to determine the message transmission rate of described each LEO satellite;

Step 103, control satellite network flow according to the message transmission rate of described each LEO satellite.

Specifically, in satellite communication system, as shown in Figure 2, when having n (n > 1) LEO satellite, i.e. LEO simultaneously ₁~ LEO _n, during with GEO satellite communication, there is a communication channel in every LEO satellite and GEO inter-satellite, total n bar channel, and the message transmission rate of each bar channel, channel capacity and snr of received signal are respectively x _i, c _iand r _i, 0≤x _i≤ c _i, i=1,2 ..., n.If GEO satellite channel capacity is over the ground when time, transmission will occur congested.In system, each LEO satellite all wishes to send data to GEO satellite in the shortest time, but the system being in congestion state can not meet each LEO satellite all with the demand of maximum rate communication.In the present embodiment, in system, each LEO satellite can regard the participant in flow control game as, and the speed of each channel constitutes whole strategy set, and each participant selects different strategies to carry out game, and ensures that system benefit is maximum.

Further, described determine GEO satellite, each LEO satellite channel capacity and the channel quality that allows of satellite system after, also comprise:

Judge GEO satellite, whether the channel quality of each LEO satellite meet the channel quality requirement of satellite system.

Further, described employing Nash Equilibrium determines the message transmission rate of each satellite, comprising:

Step one, determine based on satellite channel quality Nash Equilibrium in the revenue function of single LEO satellite be:

$U\left(x_i\right)=\frac{{\left[x_i{(1-{\mathrm{Pe}}_i)}^{x_i}\right]}^{{\mathrm{\β}}_i}}{\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}}---\left(1\right)$

Wherein, described U (x _i) be the ratio of satellite channel throughput and data accumulation time delay, described x _ifor the transmission rate of user, described Pe _ifor LEO _ithe channel bit error rate of satellite, described c is GEO satellite channel capacity over the ground, described β _ifor balance coefficient, and β _i∈ (0,1];

Specifically, the description of player, strategy and revenue function is comprised in satellite communication flow control non-cooperation Nash betting model.(1) player: in satellite communication flow control game, player refers to the user needing to transmit data, i.e. other players outside certain player i, in order to discuss conveniently, are designated as-i by each LEO satellite.In order to improve the income of oneself, every LEO satellite can the transmission rate of random Update Table.(2) strategy: in satellite communication flow control game, the strategy of user is exactly taking satellite communication resource.Each user only considers the income oneself obtained, and does not consider its amount of communications resources taken.If the communication resource that user i takies is x _i, and x _i∈ s _i, s _iit is the policy space of user i.N player respectively selects the vector of a strategy formation to be designated as x=(x ₁..., x _i... x _n), note x _-i=(x ₁..., x _i-1, x _i+1... x _n) for except user i, the vector that the strategy that other users take is formed.X _iaccording to the difference of application, its implication is different.In satellite communication flow control game, x _iit is the transmission rate of user.(3) income: income is the function of the strategy that all users take, the value realized in order to the measure user use communication resource.The revenue function of user i defines user i and to take action x _itime the benefit that obtains.In game, the income of the strategy that user adopts by revenue function and acquisition links together.Each user cannot know the strategy that other users take, and according to the revenue function of self, can only maximize the income of oneself under prescribed conditions, namely each user will safeguard the interests of oneself.

Non-cooperation Nash betting model can use G={M, S, U () } describe.Wherein, M is the user's set participating in game; S is the policy space of user in game; U () is the revenue function of user, and the total revenue that namely user obtains deducts the total punishment given.

In Fig. 1, if the data interval time of advent of each LEO satellite meets Poisson distribution, and GEO satellite forwarding data also meets Poisson distribution, then the queuing model of GEO satellite flow is typical M/M/1 model, represent that all LEO satellites arrive the data rate sum of GEO satellite, all LEO satellite datas in the accumulation time delay of GEO satellite are suppose that i-th channel received signal to noise ratio is r _i, system adopts BPSK modulation system, and its channel bit error rate is Pe _i, then the throughput of i-th channel is [x _i(1-Pe _i) ^xi] ^{β i}, β _ibalance coefficient, and β _i∈ (0,1], represent that i-th LEO satellite is to the sensitivity of flow speed.

Be defined as based on the revenue function of single LEO satellite in the non-cooperation Nash game method of channel quality:

$U\left(x_i\right)=\frac{{\left[x_i{(1-{\mathrm{Pe}}_i)}^{x_i}\right]}^{{\mathrm{\β}}_i}}{\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}}---\left(2\right)$

In formula, revenue function is the ratio of channel throughput and data accumulation time delay.Therefore, channel throughput is higher, and its revenue function is larger; And data delay is larger, revenue function is lower.This formula prefers to higher throughput, punishes larger time delay simultaneously, to improve data transmission efficiency.

By formula (1) form of taking the logarithm be:

$W\left(x_i\right)={\mathrm{\β}}_i\ln \left(x_i\right)+{\mathrm{\β}}_i{x}_i\ln (1-{\mathrm{Pe}}_i)-\ln \left(\frac{1}{c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i}\right)---\left(3\right)$

Namely the revenue function of single LEO satellite is the throughput of these satellite transmission data and the difference of time delay.

In formula (2), W (x _i) be continuous function, to x _isecond Order Continuous can be micro-, and second dervative is less than zero, therefore W (x _i) be unimodal convex function, there is maximum namely the Nash equilibrium point of this formula exists.Meanwhile, U _i()={ U ₁(), U ₂() ... U _n() } in its bounded, (boundary is hyperplane ) variable region (x ₁, x ₂..., x _n) upper unbounded, then U _i() maximum of existence anduniquess in bounded variable region.Therefore, the Nash equilibrium point of satellite communication flow control exists and unique, and revenue function reaches rate sequence during maximum constitute this Nash equilibrium point.If the channel bit error rate thresholding meeting system data quality requirement is Pe _y, namely the error rate of i-th channel exceedes the thresholding error rate, and receiving terminal cannot obtain valid data, now selects transmitting terminal not send data, namely

$x_i=\left\{\begin{array}{cc}{x}_i,& {\mathrm{Pe}}_i\≤{\mathrm{Pe}}_y\\ 0,& {\mathrm{Pe}}_i>{\mathrm{Pe}}_y\end{array}\right.---\left(4\right)$

According to above-mentioned analysis, for the non-cooperation congestion control of single bottleneck channel, Nash equilibrium solution is present in each LEO satellite revenue function value maximum point, is the first derivative zero point of formula (2).Namely

$\frac{\∂W\left(x_i\right)}{\∂x_i}=\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}=0---\left(5\right)$

According to the right equation solution namely

$\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}=0---\left(6\right)$

Formula (5) is n unit quadratic equation group, is difficult to by direct derivation the analytic solutions obtaining this formula

Described revenue function is converted to formula by step 2, employing nonlinear iteration

$f\left(x_i\right)=\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}---\left(7\right)$

To any x _imeet time, solve described formula (3),

$x_{i+1}=x_i-k\frac{f\left(x_i\right)}{f^{\′}\left(x_i\right)}=x_i-k\frac{\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}}{-\frac{{\mathrm{\β}}_i}{x_i^2}-\frac{1}{{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}^2}}---\left(8\right)$

Determine the message transmission rate of LEO satellite, wherein, described W (x _i) be the logarithmic form of formula (1), revenue function is converted to the throughput of LEO satellite transmission data and the difference of time delay.

Specifically, this embodiment introduces nonlinear equation iteration to carry out solving revenue function.First determine iteration variable, then set up a kind of rule, i.e. iteration expression formula, then set an initial value for iteration variable, obtain following element successively according to initial value and iteration expression formula.Finally, the exact solution of approaching numerical problem is gone by the limit process of the element sequence obtained successively.The present embodiment adopts Newton down-hill method to carry out the iterative of Nash equilibrium solution, formula (5) is expressed as the form of Newton iteration expression formula, order

$f\left(x_i\right)=\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}---\left(9\right)$

Then

$x_{i+1}=x_i-k\frac{f\left(x_i\right)}{f^{\′}\left(x_i\right)}=x_i-k\frac{\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}}{-\frac{{\mathrm{\β}}_i}{x_i^2}-\frac{1}{{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}^2}}---\left(10\right)$

To any x _i, all satisfied namely Newton iterated conditional is met therefore, Nash equilibrium solution is solved by Newton interative computation.

The present embodiment, the direct derivation of through type (6) is difficult to the analytic solutions obtaining this formula for this reason, the present invention adopts Newton interative computation to solve.

Satellite network flow control methods for the present embodiment emulates, if having 4 LEO satellites (LEO1 ~ LEO4) in satellite communication simultaneously by GEO satellite forwarding data, namely there are 4 channels.C _ibe the channel capacity of i-th channel, c is the channel capacity of GEO to ground station, is set to 20Mbps, and table 1 is non-all the other each optimum configurations of cooperation Nash game method simulated environment based on channel quality, as shown in table 1,

Table 1

Satellite	β i	c i(Mbps)	Pe y	Pe 1i	Pe 2i
						LEO1	0.95	6	10 -5	10 -6	10 -6
LEO2	0.80	6	10 -5	2×10 -5.5	2×10 -5.5
						LEO3	0.85	6	10 -5	3×10 -6	3×10 -4
LEO4	0.99	6	10 -5	5×10 -7	5×10 -7

Be provided with two groups of channel bit error rates, wherein first group of Pe _1ithe channel quality of middle LEO satellite all meets system requirements, second group of Pe _2iin the channel quality of LEO3 satellite be discontented with pedal system requirement.

In order to analyze the performance of the non-cooperation Nash game method based on channel quality, method the method and equal proportion being reduced each LEO satellite transmission speed compares.In emulation, suppose that channel quality all meets system requirements, namely adopt Pe _1igroup channel bit error rate, as shown in Figure 3 and Figure 4, wherein, 1 represents Nash game method to the income that the LEO satellite data transmission rate of two kinds of methods and system obtain, and 2 is equal proportion deceleration method.

Simulation result shows, each channel throughput summation that the non-cooperation Nash game method based on channel quality obtains is 13.8653Mbps, and system benefit function summation is 60.4161; And the throughput summation that the method that equal proportion reduces each LEO satellite speed obtains is 13.6749Mbps, system benefit function summation is 59.5865.Visible, the non-cooperation Nash game method based on channel quality can make system benefit function maximization.

Fig. 5 and Fig. 6 depicts data transmission rate and the revenue function of each LEO satellite obtained based on channel quality and the non-non-cooperation Nash game method based on channel quality respectively, wherein, 1 represents the non-Nash method based on channel quality, and 2 are expressed as the Nash method based on channel quality.

Based in the non-cooperation Nash game method of channel quality, the channel quality of LEO3 satellite is discontented with pedal system channel quality requirement, and this satellite does not send data, therefore the queuing delay of residue 3 LEO satellites will reduce, and income summation will increase.The speed summation of 4 the LEO satellites obtained is 14.6523Mbps, and income summation is 69.9956.If do not carry out flow control according to channel quality, still non-cooperation Nash game method is adopted, the speed summation of 4 the LEO satellites obtained is 11.9389Mbps, income summation is 47.1556, the data volume transmitted far below the non-cooperation Nash game flow control methods based on channel quality and the income of acquisition.

Visible, when each LEO satellite channel quality is higher, each channel obtains system top gain by different transmission data rates; When a certain channel quality is discontented with pedal system requirement, this channel does not send data, and the message transmission rate of all the other each channels increases thereupon, thus substantially increases the throughput of system.

The present embodiment, the embodiment of the present invention determines the channel capacity of GEO satellite, each LEO satellite and the channel bit error rate threshold value of satellite system permission, thus when the channel capacity sum of each LEO satellite is greater than the channel capacity of GEO satellite, adopt Nash Equilibrium to determine the message transmission rate of each LEO satellite, and control satellite network flow according to the message transmission rate of described each LEO satellite.During the transfer capability of the transmission rate solving in prior art many LEO satellites forwarding data simultaneously more than GEO satellite, the problem that channel resource utilance is low.The embodiment of the present invention is applicable to the non-cooperation Nash game flow control based on channel quality of LEO-GEO-earth communication system, makes entire system income the highest, instead of merely change the flow of a certain LEO satellite by the flow control of each LEO satellite.Improve the channel resource utilance of system.

Last it is noted that above each embodiment is only in order to illustrate technical scheme of the present invention, be not intended to limit; Although with reference to foregoing embodiments 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 some or all of technical characteristic; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the scope of various embodiments of the present invention technical scheme.

Claims (3)

1. a satellite network flow control methods, is characterized in that, comprising:

Determine the channel capacity of GEO satellite, each LEO satellite and the channel bit error rate threshold value of satellite system permission;

If the channel capacity sum of described each LEO satellite is greater than the channel capacity of described GEO satellite, then Nash Equilibrium is adopted to determine the message transmission rate of described each LEO satellite;

Message transmission rate according to described each LEO satellite controls satellite network flow.

2. method according to claim 1, is characterized in that, described determine GEO satellite, each LEO satellite channel capacity and the channel quality that allows of satellite system after, also comprise:

Judge GEO satellite, whether the channel quality of each LEO satellite meet the channel quality requirement of satellite system.

3. method according to claim 1 and 2, is characterized in that, described employing Nash Equilibrium determines the message transmission rate of each satellite, comprising:

Determine that the revenue function of single LEO satellite in the Nash Equilibrium based on satellite channel quality is:

$U\left(x_i\right)=\frac{{\left[x_i{(1-{\mathrm{Pe}}_i)}^{x_i}\right]}^{{\mathrm{\β}}_i}}{\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}}---\left(1\right)$

Wherein, described U (x _i) be the ratio of satellite channel throughput and data accumulation time delay, described x _ifor the transmission rate of user, described Pe _ifor LEO _ithe channel bit error rate of satellite, described c is GEO satellite channel capacity over the ground, described β _ifor balance coefficient, and β _i∈ (0,1];

Adopt nonlinear iteration that described revenue function is converted to formula

$f\left(x_i\right)=\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}---\left(2\right)$

To any x _imeet time, solve described formula (3),

$x_{i+1}=x_i-k\frac{f\left(x_i\right)}{f^{\′}\left(x_i\right)}=x_i-k\frac{\frac{{\mathrm{\β}}_i}{x_i}+{\mathrm{\β}}_i\ln (1-{\mathrm{Pe}}_i)-\frac{1}{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_1)}}{-\frac{{\mathrm{\β}}_i}{{x_i}^2}-\frac{1}{{(c-\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i)}^2}}---\left(3\right)$

Determine the message transmission rate of LEO satellite, wherein, described W (x _i) be the logarithmic form of formula (1), revenue function is converted to the throughput of LEO satellite transmission data and the difference of time delay.