CN101610105B - Satellite communication link supportable system and optimization method thereof - Google Patents

Abstract

The invention discloses a satellite communication link supportable system and an optimization method thereof. The system consists of five modules of a maximum value selection module, a logarithmic barrier processing module, an adjustable attenuation module, a penalty function processing module and an adjustable amplifier module. The optimization method firstly carries out initialization, then sequentially selects an initial neighbourhood, obtains a new point in the initial neighbourhood, carries out local research and finally carries out neighborhood change. The application of the link supportable system and the optimization method thereof can effectively solve the difficult problem of co-exist of big and small carriers in a multi-carrier satellite communication system, improves the capacity of the system and the power utilization rate of a transponder and has very important theoretical guiding significance and engineering practical value for the design of the satellite communication system.

Description

A kind of satellite communication link supportable system and optimization method thereof

Technical field

The invention belongs to technical field of satellite communication, be specifically related to a kind of satellite communication link supportable system and optimization method thereof.

Background technology

Now, many satellite communication systems adopt multi-beam frequency division multiple access (Frequency-division multiple access abbreviates FDMA as) communication system.Under this communication system, system can compatible various types of ground based terminals, comprise airborne, carrier-borne, vehicle-mounted even hand-held terminal device.For waiting the residing satellite communication link of small aperture terminal as handing, it is more valuable that the power resource of satellite is compared bandwidth resources; Simultaneously, in this multicarrier satellite system, the power amplifier of satellite repeater will amplify a plurality of carrier waves simultaneously.Because power amplifier non-linear, multi-carrier signal during through transponder, can produce Intermodulation Interference, the strong signal phenomenons such as inhibition to weak signal.Usually; For fear of or reduce these phenomenons to the satellite system Effect on Performance; The transponder power amplifier must operate at linear zone; This just causes the power utilization of satellite repeater to descend, and to cause big carrier wave be that the higher carrier wave of power is that the lower carrier wave of power has certain depression effect to little carrier wave.The multicarrier operating state has hindered effective utilization of satellite power.Therefore; The loading analysis of satellite communication system is especially analyzed each communication link supportable in the system, promptly confirms each up effective isotropic radiated power (Effective Isotropic Radiated Power; Abbreviate EIRP as), optimize high power amplifier (High Power Amplifier in gain and the transponder of satellite repeater; Abbreviate HPA as) being provided with etc. of working point, how effectively to utilize satellite repeater power, overcome the problems such as inhibition of big carrier wave thereby solve little carrier wave, improve the performance of satellite communication system; Meaning is very great, is an important subject of system optimization design.

Traditional Transparent Transponder can only be carried out integral body adjustment to repeater gain, therefore big or small carrier wave coexistence, satellite repeater power effectively utilize the problem multicarrier satellite communication system of always puzzling.Along with the digital channelizing The Application of Technology, the solution of the problems referred to above has had new thinking, and makes a breakthrough.In the digital channelizing technology, the subchannel of certain bandwidth in each up user from occupying up-channel carries out subchannel with filtering method on the star and separates; Extract each subscriber signal; After circuit switching, combine each subscriber signal again, get into downlink wave beam.This shows that after utilization digital channelizing technology, the gain of each subchannel can be adjusted respectively in the multicarrier satellite repeater, for the link supportable analysis provides new thinking.

The link supportable of satellite communication system is meant the essential up EIRP of ground based terminal in the satellite system and the relation between its available maximum EIRP; That is: under the condition that recipient's carrier-to-noise ratio meets the demands; If the essential up EIRP of transmitting party is less than its available maximum EIRP; Claim that then this communication link has supportable, promptly in the case, this link can be kept normal communication; Otherwise, if the essential up EIRP of transmitting party more than or equal to its available maximum EIRP, claims that then this communication link does not have supportable.In satellite communication system, the number of links with supportable is many more, and the capacity of system is also just high more.Obviously, link supportable is an important indicator of reflection satellite communication system performance.For the digital channelizing satellite communication system; The task of link supportable analysis is the gain of confirming the up EIRP of each link, optimizing each subchannel in the transponder; Thereby the working point of HPA in the optimization transponder; Reach and overcome a large and small carrier wave coexistence difficult problem, the purpose of raising satellite repeater power utilization.It is thus clear that the link supportable analysis has very important theory directive significance and engineering practical value for the planning and design of novel satellite communication system.

Summary of the invention

The problem that the objective of the invention is to be difficult to coexist in order to overcome big or small carrier wave in the conventional satellite communication, the transponder power utilance is low proposes a kind of link supportable system of satellite communication, and to this system, proposes a kind of heuristic optimization method.The result of global optimum who uses this optimization method to come the said link supportable system of optimization process obtains the best transmit power of each subchannel optimum gain and each link in the satellite repeater.This link supportable system reaches following purpose through the maximum carrier power in the satellite repeater output is minimized:

A) dwindle the difference of each carrier power in the transponder as far as possible, avoid each carrier power uneven, thereby can the repeater operation point be arranged on optimal location, improve the power utilization of transponder;

B) minimize the up EIRP at each terminal, make link as much as possible can realize proper communication, thereby improve the capacity of system.

In order to achieve the above object, proposed a kind of satellite communication link supportable system, this system chooses module, logarithm obstacle processing module, adjustable damping module, penalty function processing module and five modules of adjustable amplification module by maximum and forms.Wherein, first input signal input logarithm obstacle processing module, the output signal input adjustable damping module of logarithm obstacle processing module; Second input signal input maximum is chosen module; The 3rd input signal input penalty function processing module, the output signal of penalty function processing module is imported adjustable amplification module; The difference signal with signal and adjustable damping module output signal that maximum is chosen module and two module output signals of adjustable amplification module becomes the output signal of satellite communication link supportable system of the present invention.

Based on said system of the present invention, a kind of optimization method of satellite communication link supportable system may further comprise the steps:

Step 1: initialization

Construct two neighborhoods, select initial point and formulate the end condition of processing procedure;

Step 2: choose initial neighborhood

Choose a neighborhood as initial neighborhood;

Step 3: obtain the new point in the initial neighborhood

Acquisition point is as the new point in the initial neighborhood at random;

Step 4: Local Search

New with what obtain in the step 3 as initial point, in another neighborhood, obtain another new point as Local Search;

Step 5: neighborhood change.

In sum; The optimization method of the satellite communication link supportable system that the link supportable system that utilization the present invention proposes and the present invention propose is analyzed the digital channelizing satellite communication system; Can solve the intrinsic problem in traditional multicarrier satellite communication system very effectively; The capacity of raising system, promptly a satellite communication system can be held more different types of ground based terminal; Improve the power utilization of satellite repeater simultaneously, more effectively utilize the power resource of satellite.This link supportable system and optimization method thereof have very important theory directive significance and engineering practical value concerning the design engineer of digital channelizing satellite communication system.

The invention has the advantages that:

(1) native system has solved the intrinsic problem of traditional multicarrier transparent forwarding satellite communication system under the fit applications of digital channelizing technology: big or small carrier wave is difficult to coexistence, the transponder power utilance is not high;

(2) this method is a kind of global optimum method, and compares such as the optimization method of classics such as SQP method, and the latter is when optimization process satellite communication link supportable system of the present invention; Very responsive to choosing of initial value; Initial value is different, and the result who obtains is different, and difference is very big; The former does not then have this defective.

Description of drawings

Fig. 1 is the channel model of existing digital channelizing satellite communication system;

Fig. 2 is a satellite communication link supportable system block diagram of the present invention;

Fig. 3 is for confirming the method flow diagram of line search step-length in the optimization method of satellite communication link supportable system of the present invention;

Fig. 4 is the optimization method flow chart of satellite communication link supportable system of the present invention.

Among the figure: 1. satellite repeater 2. M ground launch terminals 3. first ground launch terminals

4. M ground receiving terminal 5. first ground receiving terminals 6. maximums are chosen module

7. logarithm obstacle processing module 8. adjustable damping modules 9. penalty function processing modules

10. adjustable amplification module

Embodiment

To combine accompanying drawing that the present invention is done further explain below.

The present invention is a kind of satellite communication link supportable system and optimization method thereof.Fig. 1 is the channel model of existing digital channelizing satellite communication system; This model comprises satellite repeater 1, M ground launch terminal 2, the first ground launch terminal 3, M ground receiving terminal 4 and the first ground receiving terminal 5; Wherein satellite repeater 1 receives the upward signal from the first ground launch terminal 3 and M ground launch terminal 2, and sends to the first ground receiving terminal 5 and M ground receiving terminal 4 respectively after the signal that receives handled.To should channel model, suppose that a subchannel can hold several little carrier waves, a big carrier wave can take several adjacent sub-channel.Do not consider the quantity of antenna, single transponder has the N subchannel holding M carrier wave, and has only a HPA in each transponder, its non-linear Intermodulation Interference that causes.For link i, i=1 wherein, 2 ..., M, the up EIRP of note ground launch terminal is E _i, the up link loss is a _i, it comprises that free-space loss, scattering loss, rain decline and the satellite earth antenna gain G _{U, a}, downlink loss is b _i, it comprises the satellite transmitting antenna gain G _{D, a}, free-space loss, scattering loss, rain declines and the antenna gain of ground receiving terminal.Each carrier power of transponder input is x _i, each carrier power of output is y _iMake k represent Boltzmann constant, T _sThe system noise temperature of expression transponder, T _iThe system noise temperature of representing receiving terminal in this link.Then transponder can be modeled as: having density is kT _sAdditive noise, desirable subchannel G _n, desirable filtering, memoryless non-linear, n=1 wherein, 2 ..., N.Concerning all subchannels, additive noise is with non-linear all identical, but gain is different with filtering.The overall gain of transponder is embodied in each subchannel gains G _nOn, and under the small-signal situation, the gain of HPA is 1.

When the basic parameter of satellite communication system was known, the up path loss was known, and at this moment, the essential up EIRP that confirms the terminal is equivalent to and confirms the essential input power x of transponder _i, i=1 wherein, 2 ..., M.

In order to analyze link supportable, also to confirm the operating point of transponder, on this operating point, assess the non-linear influence of HPA, the setting of removing optimization work point based on this influence to multi-carrier signal.For this reason, the working point of definition transponder is: do not having under the situation of gain compression, the gross power of transponder output is designated as z with respect to the normalized value of saturation power P, then:

$z=\frac{1}{P}(\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{x}_i{G}_{n\left(i\right)}+k{T}_s\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{G}_n{B}_n)---\left(1\right)$

Wherein: G _nBe the gain of n subchannel, G _{N (i)}Be the gain of the n subchannel of distributing to link i, n (i) expression subchannel n distributes to link i, B _nThe bandwidth of representing the n subchannel.

Definition gain compression amount is the function of repeater operation point z, for the sake of simplicity, supposes that the gain compression of all links is all identical, is designated as g (z), and then for link i, the net gain that the upward signal at terminal obtains behind the transponder via satellite is G _{N (i)}/ g (z), the outgoing carrier power y of transponder _i=x _iG _{N (i)}/ g (z).

Suppose that Intermodulation Interference is white, and its spectrum density is the function of working point, remembers that normalized Intermodulation Interference characteristic function is h (z), then the actual Intermodulation Interference spectrum density of transponder output place is h (z) P/B, and B is the total bandwidth of transponder here.

Therefore, when modeling, the maximum carrier power that transponder is exported minimizes, and guarantees that simultaneously the carrier-to-noise ratio of link satisfies the error rate of system performance requirement, and in view of the above, the link supportable of digital channelizing satellite communication system is modeled as:

$\min \mathrm{imize}\underset{1\≤i\≤M}{\max }{y}_i---\left(2\right)$

Formula (2) is the maximum of picking out in all carrier powers of output of transponder, and this maximum is minimized.

Suppose that the aggregate date rate that link i supports is R _b, c _iBe the essential carrier-to-noise ratio of this link, according to the recipient E of system _b/ N ₀Demand, have

$c_i={\left(\frac{E_b}{N_0}\right)}_i\×R_b---\left(3\right)$

E wherein _bBe to send the required energy of every bit information, N ₀It is noise spectral density.Make link i satisfy the error rate of system performance demands, then must make recipient's in this link actual carrier-to-noise ratio more than or equal to c _i, promptly

$\frac{y_i/b_i}{\left(\frac{{\mathrm{kT}}_s{G}_{n\left(i\right)}}{g\left(z\right)b_i}\right)+\frac{1}{b_i}\underset{j\≠i}{\mathrm{\Σ}}{\mathrm{\Δ}}_{\mathrm{ij}}{y}_i+\frac{h\left(z\right)P}{{\mathrm{Bb}}_i}+{\mathrm{kT}}_i}\≥c_i---\left(4\right)$

Wherein: molecule y _i/ b _iThe signal power of expression receiving terminal demodulator porch; Denominator is represented noise and interference, comprises the uplink noise of amplification

Monkey chatter

Intermodulation Interference

And downlink noise kT _iHere, Δ _IjBe the transponder power output of residual link j in the link i filter, promptly

Δ _ij＝∫S _i(f)S _j(f)df

Wherein: S _i(f) and S _j(f) represent the normalized power spectral density of carrier wave i and carrier wave j respectively.

Therefore, but the satellite communication link supportable system complete expression be:

$\min \mathrm{imize}\underset{1\≤i\≤M}{\max }{y}_i$

$\mathrm{subjectto}\frac{y_i/b_i}{f_i\left(Y\right)}\≥c_i,1\≤i\≤M,---\left(5\right)$

$z=\frac{1}{P}(\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{x}_i{G}_{n\left(i\right)}+{\mathrm{kT}}_s\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{G}_n{B}_n)$

Formula (5) is the mathematic(al) representation of the link supportable system of digital channelizing satellite communication system of the present invention.Wherein: $f_i\left(Y\right)=\left(\frac{{\mathrm{KT}}_s{G}_{n\left(i\right)}}{g\left(z\right)b_i}\right)+\frac{1}{b_i}\underset{j\≠i}{\mathrm{\Σ}}{\mathrm{\Δ}}_{\mathrm{Ij}}{y}_i+\frac{h\left(z\right)P}{{\mathrm{Bb}}_i}+{\mathrm{KT}}_i,$ y _i=x _iG _{N (i)}/ g (z).Here, x _iAnd G _{N (i)}Be design variable, i=1 wherein, 2 ..., M.First constraints $\frac{y_i/b_i}{f_i\left(Y\right)}\≥c_i,$ 1≤i≤M guarantees that each link recipient carrier-to-noise ratio satisfies system's error performance requirement; Second constraints $z=\frac{1}{P}(\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{x}_i{G}_{n\left(i\right)}+{\mathrm{KT}}_s\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{G}_n{B}_n)$ The working point of guaranteeing HPA in the transponder is away from nonlinear area.Through logarithm obstruction method and penalty function method (5) formula is converted into

$\min \mathrm{imize}\underset{1\≤i\≤M}{\mathrm{mex}}{y}_i-\mathrm{\μ}\underset{i=1}{\overset{M}{\text{\Σ}}}\log (\frac{y_i/b_i}{f_i\left(Y\right)}-c_i)+\mathrm{\σ}{(z-q(X,G))}^2---\left(6\right)$

Formula (6) is that the unconfinement of (5) formula is optimized the form of expression.Wherein: f _i(Y) with (5) formula in consistent; $q(X,G)=\frac{1}{P}(\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{x}_i{G}_{n\left(i\right)}+{\mathrm{KT}}_s\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{G}_n{B}_n);$ μ is an obstruction factor, and value is 10 ^-5σ is a penalty factor, and value is 100.

Therefore, the satellite communication link supportable system that the present invention proposes is chosen module 6, logarithm obstacle processing module 7, adjustable damping module 8, penalty function processing module 9 and 10 5 modules of adjustable amplification module by maximum and formed, and is as shown in Figure 2.Wherein, first input signal input logarithm obstacle processing module 7, the output signal input adjustable damping module 8 of logarithm obstacle processing module 7; Second input signal input maximum is chosen module 6; The 3rd input signal input penalty function processing module 9, the output signal of penalty function processing module 9 is imported adjustable amplification module 10; The difference signal of exporting signals with signal and adjustable damping module 8 that maximum is chosen module 6 and 10 two module output signals of adjustable amplification module becomes the output signal of satellite communication link supportable system of the present invention.Wherein, maximum is chosen module 6, the max in the corresponding (6) _1≤i≤My _i, from second input signal, pick out maximum input signal; Logarithm obstacle processing module 7, in corresponding (6) formula $\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\mathrm{Log}(\frac{y_i/b_i}{f_i\left(Y\right)}-c_i),$ First input signal is taken the logarithm, then summation; Adjustable damping module 8 is carried out the variable attenuation adjusting with the output result of logarithm obstacle processing module 7, and attenuation is μ; Penalty function processing module 9, (the z-q (X, G)) in corresponding (6) formula ², detect the level of the 3rd input signal and the error between the expected level, then with this error square as output signal; The output signal of 10 pairs of penalty function processing modules 9 of adjustable amplification module carries out adjustable amplification to be regulated, and amplification quantity is σ.

A kind of effective optimization method of design is optimized processing to the link supportable system of top foundation below, and obtain the result of its global optimum: each carrier wave is at the power x of satellite repeater input place _iGain G with each subchannel in the satellite repeater _n, i=1 wherein, 2 ..., M, n=1,2 ..., N; At last,, comprise the setting to the up EIRP at this each terminal of system, the setting of satellite repeater intermediate power amplifier, accomplish the task that the system link supportable is analyzed according to this global optimum digital channelizing satellite communication system of studying of configure as a result.For this reason, construct two neighborhood N ₁And N ₂

N ₁The constitution step of neighborhood is:

A) obtain the random search direction

Obtain 4M different random search direction d according to following method ₁, d ₂..., d _4M

$d_j=\left\{\begin{array}{cc}1,& u\∈[\mathrm{0,1}/3)\\ 0,& u\∈[1/\mathrm{3,2}/3)\\ -1,& u\∈[2/\mathrm{3,1}]\end{array}\right.$

Wherein: u is for being evenly distributed on the random number on the interval [0,1];

B) confirm line search interval

If wait to ask the independent variable x ∈ [x of problem _L, x _U], in the j time iterative process, current point is x _j, the current search direction is d _j, consider current search direction d _jCan be positive number, negative or 0, therefore with step-size in search λ _jBe restricted to non-bearing, i.e. λ _j>=0.

Because

x _L≤x _j≤x _U (7)

The point x that obtains after once of iteration then _j+ λ _jd _jAlso should satisfy

x _L≤x _j+λ _jd _j≤x _U (8)

If x _L(i), x _U(i), x _j(i) and d _j(i) represent x respectively _L, x _U, x _jAnd d _jI component, i=1 wherein, 2 ..., 2M; x _LBe the lower bound of independent variable x, x _UBe the upper bound of independent variable x, x _jBe current point, d _jIt is the current search direction.Then have according to (8) formula

x _L(i)≤x _j(i)+λ _jd _j(i)≤x _U(i)

Again according to (7) formula

x _L(i)≤x _j(i)≤x _U(i)

So:

Situation one: work as d _j(i)=1 o'clock, can get 0≤λ _j≤x _U(i)-x _j(i)

Important to institute, about λ _jThe result get common factor, obtain d _j(i)=1 (i=1,2 ..., λ in the time of 2M) _jLine search interval [a, b] do $[0,\underset{1\≤i\≤M}{\mathrm{Min}}(x_U\left(i\right)-x_j\left(i\right))];$

Situation two: work as d _j(i)=0 o'clock, can get 0≤λ _j＜+∞

Important to institute, about λ _jThe result get common factor, obtain d _j(i)=0 (i=1,2 ..., λ in the time of 2M) _jLine search interval [a, b] be [0 ,+∞);

Situation three: work as d _j(i)=-1 o'clock, can get 0≤λ _j≤x _j(i)-x _L(i)

Important to institute, about λ _jThe result get common factor, obtain d _j(i)=-1 (i=1,2 ..., λ in the time of 2M) _jLine search interval [a, b] do $[0,\underset{1\≤i\≤M}{\mathrm{Min}}(x_j\left(i\right)-x_L\left(i\right))];$

C) confirm step-size in search

At first, initialization:

Make step-size in search λ _jFirst recruitment l=1, the compressibility factor s=10 of this recruitment, variable quantity δ=0.5 of hunting zone, the thresholding δ of search procedure _f=0.05, best step-size in search λ ^*=λ _i=a, current optimal function is min=f (x+ λ as a result _iD);

Secondly, step-size in search disturbance:

Make step-size in search λ _iIncrease a quantitative l, and whether the step-size in search of inspection after increasing exceed the step-size in search scope that step 2 is formulated, if exceeded, expanded search scope a=λ then ^*-δ, b=λ ^*+ δ, and write down current function result f (x+ λ ^*D) as optimum, with the recruitment boil down to l/s of step-size in search; If do not exceed, then check current function result f (x+ λ _iD) whether less than the optimum that writes down, if, then repeat this perturbation process, otherwise, change search over to and stop;

At last, obtain step-size in search:

Propagation δ=δ/the s of compression step length searching scope, and whether inspection δ is less than the threshold delta of search procedure _f, if, then stopping search procedure, the step-size in search of this moment is best step-size in search; Otherwise restart this search procedure.As shown in Figure 3.

D) confirm optimum orientation and the best step-length of upgrading

Find out optimum orientation d ^*And corresponding with it the best is upgraded step-length λ ^*, they satisfy

$f(x_j+{\mathrm{\λ}}^{*}{d}^{*})=\underset{1\≤i\≤2M}{\min }f(x_j+{\mathrm{\λ}}_i{d}_i)$

Wherein: f representes the target function of problem to be solved, x _jBe the starting point of j iteration, λ _iBe c) in the step-size in search confirmed, d _jBe the direction of search of obtaining in a).

E) upgrade current point

If the optimal value of pending optimization problem target function is f ^*If, f (x _j+ λ ^*d ^*)＜f ^*, then upgrade current point and optimal value, i.e. x _J+1=x _j+ λ ^*d ^*, f ^*=f (x _j+ λ ^*d ^*)

Otherwise current point and optimal value are not updated.

N ₂The constitution step of neighborhood is:

If the variable of waiting to ask problem for (x, y), (1＜x, y＜1).

A) confirm initial point and search moving direction

If the search initial point is (x _Initial ^Best, y _Initial ^Best), x wherein _Initial ^BestThe x component of representing best initial point, y _Initial ^BestThe y component of representing best initial point is then searched for moving direction and is confirmed according to following rule

Order

${\stackrel{\‾}{x}}_{\mathrm{initial}}^{\mathrm{best}}=(x_{\mathrm{initial}}^{\mathrm{best}}+0.99x_{\mathrm{initial}}^{\mathrm{best}})/2$

${\stackrel{\‾}{y}}_{\mathrm{initial}}^{\mathrm{best}}=(y_{\mathrm{initial}}^{\mathrm{best}}+0.99y_{\mathrm{initial}}^{\mathrm{best}})/2$

If $f({\stackrel{\‾}{x}}_{\mathrm{Initial}}^{\mathrm{Best}},y_{\mathrm{Initial}}^{\mathrm{Best}})\≤f(x_{\mathrm{Initial}}^{\mathrm{Best}},y_{\mathrm{Initial}}^{\mathrm{Best}}),$ Then the direction of search on the x component is+1; Otherwise, be-1;

If $f(x_{\mathrm{Initial}}^{\mathrm{Best}},{\stackrel{\‾}{y}}_{\mathrm{Initial}}^{\mathrm{Best}})\≤f(x_{\mathrm{Initial}}^{\mathrm{Best}},y_{\mathrm{Initial}}^{\mathrm{Best}}),$ Then the direction of search on the y component is+1; Otherwise, be-1;

B) confirm step-size in search

The step-size in search Δ is for being evenly distributed on the random number on the interval [α, α], and the initial value of α is taken as 0.5, after each search iteration, with 0.67 * α as the α of search iteration next time.

C) confirm the iteration update mode

If (x _T-1, y _T-1) solution vector that obtains behind the t-1 time iterative search of expression, the then solution vector (x that obtains of the t time iterative search _t, y _t) follow following renewal rule:

x _t＝x _t-1±Δ，(t＝1，2，…，T) (9)

y _t＝y _t-1±Δ，(t＝1，2，…，T) (10)

Wherein: maximum iteration time T is chosen for 500; When the search moving direction of confirming in the step 1 is+1, get in (9) and (10) '+'; Otherwise get '-'.

Like this, as shown in Figure 4, the complete optimization method of satellite communication link supportable system of the present invention may further comprise the steps:

Step 1: initialization

Two neighborhood N of constitution step structure according to above-mentioned neighborhood ₁And N ₂, select initial point x and formulate the end condition of processing procedure;

Step 2: choose initial neighborhood

Because constructing two neighborhoods in the present invention just is enough to reach the object of the invention, therefore choose neighborhood N ₁As initial neighborhood;

Step 3: obtain the new point in the initial neighborhood

Acquisition point y ∈ N at random _k(x ^*), k=1,2 as the new point in the initial neighborhood;

Step 4: Local Search

With the new point that obtains in the step 3 is that y is an initial point, at neighborhood N ₂In newly put y ' as Local Search;

Step 5: neighborhood change

The target function at the new some place that obtains in the determining step four as a result f (y ') whether less than current optimal value f ^*, if then move to new some y ', and make optimal function f as a result ^*=f (y '), and whether the processing procedure end condition that inspection is formulated in the step 1 satisfy, if satisfy, termination process then, otherwise jump back to step 2, restart this processing procedure.As shown in Figure 4.

Then, according among Fig. 4 about the optimization method step of satellite communication link supportable system of the present invention, (6) formula is optimized processing, obtain each subchannel gains G _n, n=1 wherein, 2 ..., N, and each carrier wave is in the input power x at transponder place _i, i=1 wherein, 2 ..., M obtains the up effective isotropic radiated power at each terminal again according to formula (11)

$E_i=\frac{x_i{a}_i}{G_{u,a}}---\left(11\right)$

According to this G _nAnd E _i, the surface launching terminal, various places and the satellite repeater of system is provided with, make whole satellite communication system be in optimum Working.

Below introduce the embodiment of link supportable system of the present invention and optimization method:

Before introducing concrete embodiment, provide the parameter that needs utilization among each embodiment:

Table 1 satellite basic parameter table

Upstream frequency (GHz)	31
		Downstream frequency (GHz)	21.2
Channel width (MHz)	124.8
		EIRP(dBW)	55.2
G/T(dB/deg.)	8.4
		Saturation flux density (dBW/m2)	-89.4
Equivalent noise temperature (deg.)	1819
		Saturation power (W)	34
Receiving antenna gain (dBi)	41
		Transmitter antenna gain (dBi) (dBi)	39.9
Repeater gain scope (dB)	100-150

Have two Terminal Types in the system, antenna aperture is respectively 8 feet and 2 feet.The basic parameter of this two Terminal Type is as shown in table 2.

Table 2 terminal basic parameter table

Terminal nominal size (foot)	8	2
			Transmitter antenna gain (dBi) (dBi)	55.2	43.2
Receiving antenna gain (dBi)	51.9	39.3
			Noise temperature (deg.)	450	450
Maximum transmission power (W)	25	5
			Maximum EIRP (dBW)	69.2	50.2
G/T(dB/deg.)	25.4	13.4

Be provided with 16 links in the system altogether, wherein four links are: 2-foot terminal is sent out 8-foot terminal and is received, and transmission rate is 1Mbps; Four links are in addition: 8-foot terminal is sent out 2-foot terminal and is received, and transmission rate is 1Mbps; Eight remaining links are: 8-foot terminal is sent out 8-foot terminal and is received, and transmission rate is 10Mbps.For the sake of simplicity, establish the E of all links _b/ N ₀Demand is 5dB, and the down link rain surplus that declines is 5dB.Total channel width is 124.8MHz in the system; Be divided into 48 subchannel; Each subchannel bandwidth 2.6MHz distributes two subchannel to send out four 1Mbps links that receive at 8-foot terminal for 2-foot terminal, and other distributes two subchannel to send out four 1Mbps links that receive at 2-foot terminal for 8-foot terminal; Also distribute 34 subchannel to send out eight 10Mbps links that receive at 8-foot terminal for 8-foot terminal, 10 remaining subchannel are idle.The basic parameter of link is as shown in table 3, wherein c _iObtain according to (3) formula:

Table 3 link basic parameter table

Linktype	c i	Occupied bandwidth (MHz)
			1Mbps, 2-foot send out the 8-foot and receive	1.0e7	2×2.6
1Mbps, 8-foot send out the 2-foot and receive	1.0e7	2×2.6
			10Mbps, 8-foot send out the 8-foot and receive	1.0e8	34×2.6

Transponder nonlinear characteristic function g (z) and Intermodulation Interference characteristic function h (z) get respectively:

g(z)＝1+1.27z

$h\left(z\right)=\frac{0.123}{{(1+1/z)}^3}$

Embodiment one: with the link supportable system of the present invention's proposition and the link supportable of optimization method analysis satellite communication system

Adopt digital channelizing satellite communication link supportable system of the present invention and optimization method thereof that the link supportable of digital channelizing satellite communication system is analyzed, the result is as shown in table 4.

Table 4 applied satellite communication link supportable system and optimization method thereof are analyzed the result that link supportable obtains

Linktype	Gain (dB)	Essential EIRP (dBW)	Maximum EIRP (dBW)
				1Mbps, 2-foot send out the 8-foot and receive	125.21	48.50	50.2
1Mbps, 8-foot send out the 2-foot and receive	107.88	67.62	69.2
				10Mbps, 8-foot send out the 8-foot and receive	111.89	64.24	69.2

Can know that from table 4 in all three kinds of links, the essential up EIRP of launch terminal therefore all can be by system's support less than its maximum EIRP.In the case, the link supporting rate reaches 16/16, that is to say, the link supportable system that the present invention proposes has solved the contradiction that the system size carrier wave is difficult to coexist, and has improved the capacity of satellite system.

Embodiment two: the power utilization of transponder in link supportable system that proposes with the present invention and the methods analyst satellite system.

For the digital channelizing satellite communication system, existing link supportable system is suc as formula the p norm system shown in (12)

$\min \mathrm{imize}\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{y}_i^p,p\≥1---\left(12\right)$

$\mathrm{subjectto}\frac{y_i/b_i}{f_i\left(Y\right)}\≥c_i,1\≤i\≤M.$

Wherein: f _i(Y) with (5) formula in consistent.

Utilization Lagrange multiplier method treatment system (12), the result who obtains the transponder power utilance is shown in second line data in the table 5; And the result of the transponder power utilance that the optimization method that utilization the present invention proposes obtains is shown in the third line data in the table 5.

Under two kinds of models of table 5, satellite repeater power utilization result contrast

Link supportable system	Total essential up EIRP (dBW)	The descending EIRP (dBW) that transponder is total
			P norm system	77.19	49.53
System of the present invention	76.50	51.26

Visible from table 5, link supportable system that the present invention carries has higher transponder power utilance, and promptly total descending EIRP brings up to the 51.26dBW of system of the present invention by the 49.53dBW of " p norm system ", and power utilization improves 48% approximately.

The optimization processing method that the link supportable system that utilization the present invention proposes and the present invention propose is analyzed the digital channelizing satellite communication system; Can solve the intrinsic problem in traditional multicarrier satellite communication system very effectively; The capacity of raising system, promptly a satellite communication system can be held more different types of ground based terminal; Improve the power utilization of satellite repeater simultaneously, more effectively utilize the power resource of satellite.This link supportable system and optimization method thereof have very important theory directive significance and engineering practical value concerning the design engineer of digital channelizing satellite communication system.

Claims (1)

1. a satellite communication link supportable system is characterized in that, this system chooses module (6), logarithm obstacle processing module (7), adjustable damping module (8), penalty function processing module (9) and (10) five modules of adjustable amplification module by maximum and forms,

First input signal input logarithm obstacle processing module (7), the output signal input adjustable damping module (8) of logarithm obstacle processing module (7); Second input signal input maximum is chosen module (6); The 3rd input signal input penalty function processing module (9), the output signal of penalty function processing module (9) is imported adjustable amplification module (10); The difference signal with signal and adjustable damping module (8) output signal that maximum is chosen module (6) and (10) two module output signals of adjustable amplification module becomes the output signal of this satellite communication link supportable system;

The all module mutual group of this system are built up a model, and its expression formula is:

Wherein: N is the number of satellite repeater sub-channels, and M is carrier wave or a quantity of links in the satellite repeater, G _nBe the gain of n subchannel, n=1,2 ..., N, n (i) expression subchannel n distributes to link i, i=1,2 ..., M, G _{N (i)}Be the gain of the n subchannel of distributing to link i, B _nThe bandwidth of representing the n subchannel, k representes Boltzmann constant, T _sThe system noise temperature of expression satellite repeater, x _iBe each carrier power of satellite repeater input, y _iBe each carrier power of satellite repeater output, b _iBe the loss of satellite downlink i, c _iBe the essential carrier-to-noise ratio of link i, P is the saturation power of satellite repeater, y _i=x _iG _{N (i)}/ g (z), T _iThe system noise temperature of receiving terminal among the expression link i, B is the total bandwidth of satellite repeater, and g (z) is the nonlinear characteristic function of satellite repeater about its high power amplifier HPA working point z, and h (z) is an Intermodulation Interference characteristic function in the satellite repeater, Δ _IjSatellite repeater power output for residual link j in the link i filter; First constraints

Guarantee that each link recipient carrier-to-noise ratio satisfies system's error performance requirement; Second constraints

The working point of guaranteeing high power amplifier HPA in the transponder is away from nonlinear area;

Through logarithm obstruction method and penalty function method following formula is converted into unconfinement and optimizes the form of expression:

Wherein:

μ is an obstruction factor, and value is 10 ^-5σ is a penalty factor, and value is 100;

Wherein, to choose the model of module (6) be the max in the following formula to maximum _1≤i≤My _i, maximum is chosen module (6) and from second input signal, is picked out maximum input signal;

The model of logarithm obstacle processing module (7) is that

logarithm obstacle processing module (7) is taken the logarithm to first input signal in the following formula, then summation;

Adjustable damping module (8) is carried out the variable attenuation adjusting with the output result of logarithm obstacle processing module (7), and attenuation is the μ in the following formula;

The model of penalty function processing module (9) is (z-q (X, G)) in the following formula ², penalty function processing module (9) detects the level of the 3rd input signal and the error between the expected level, then with this error square as exporting signal;

Adjustable amplification module (10) carries out adjustable amplification adjusting to the output signal of penalty function processing module (9), and amplification quantity is the σ in the following formula.

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