CN103402212A - Method for macrocell user (MUE) selecting femtocell user (FUE) for relay coordination - Google Patents

Abstract

The invention provides a method for an MUE selecting an FUE for relay coordination. The method comprises the steps that 1) multiple MUE's and multiple FUE's employ a cooperative transmission mode, and a time-slot distribution protocol is prescribed; 2) relay efficacy of different FUE's for each MUE is respectively calculated; 3) each MUE sequentially selects an FUE relay set according to efficacy parameters; and 4) if one FUE is selected by multiple MUE's, all possible selection combination schemes are ergodic, a scheme in which the product of MUE efficacy increments is the maximal is selected as the optimal strategy, and a relay selection set for each MUE is determined according to the optimal strategy. According to the invention, when multiple FUE's monopolize frequency spectrum of the network, the multiple MUE's are guided to effectively select relay coordination of the FUE's, and the fairness among the MUE's is also considered; and thus, the method of the invention is less in operand and better in performance compared with a full-permutation algorithm.

Description

Macrocellular user MUE selects to fly phone user FUE and assists the method for relaying

Technical field

The present invention relates to communication technical field, particularly, relate to a kind of macrocellular user MUE and select to fly the method for phone user FUE assistance relaying.

Background technology

, fly honeycomb (Femtocell) and attract wide attention in academic and industrial quarters for the more requirement of low energy consumption in higher wireless transmission rate, wider wireless coverage and " green radio " based on people.Fly the setting of honeycomb access point at home,, as the user access core network of relaying help away from macro base station, reduced macrocellular (Macrocell) user's energy consumption.Yet,, for capacity and the back haul link of preserving self, many times fly honeycomb owner tendency and take closed access in up link, for example in macrocellular-fly cellular frequency spectrum is monopolized network.When macrocellular-fly honeycomb is taked cooperation policy,, if a macrocellular user (MUE) moves to the macro cells edge, but approach, fly cellular coverage, can employ some channel conditions to fly preferably phone user (FUE) and help relaying.Owing to flying between honeycomb access point (FAP) and macrocell base stations (MBS) to pass through wired connection, MUE can assist relay data to FAP by FUE, thereby realizes transfer of data.This has overcome the problem of bad channel quality when MUE directly transmits to MBS, helps MUE to save energy consumption.Simultaneously, these provide the FUE of service to obtain part-time in the MUE transmission structure to transmit in return the data of oneself.Such modality for co-operation is the situation that MUE and FUE have created win-win.

In recent years, about the MUE-FUE collaborative problem, caused the research that people are extensive, the stability of cooperation and the key of service quality are that one overlaps careful and effective resource allocation mechanism.Find by prior art documents, Linjie Duan, Jianwei Huang and Biying Shou will be in " Economics of femtocell service provision " (fly honeycomb the economics of service is provided) literary compositions of delivering on IEEE Transactions on Mobile Computing in 2013,, by the subgame perfect equilibrium of Stackelberg game, studied mobile operator and introduced the Economic Motivation that flies cellular service on current macrocellular service.

But above-mentioned technology when considering to maximize all MUE overall interests, is not considered the fairness between MUE.The assorted bargaining problem of receiving of considering fairness is the NP-hard problem, and existing exhaust algorithm, because amount of calculation is excessive, is difficult to realize in actual environment.

Summary of the invention

For defect of the prior art, the purpose of this invention is to provide a kind of macrocellular user MUE and select to fly the method for phone user FUE assistance relaying, guarantee to distribute liberally on the maximized basis of overall interests the strategy of a plurality of FUE.

According to an aspect of the present invention, provide a kind of macrocellular user MUE to select to fly phone user FUE and assist the method for relaying, it is characterized in that, comprise the steps:

The first step: a plurality of MUE and a plurality of FUE take the cooperation transmission mode, and regulation time slot allocation agreement;

Second step: calculating different FUE is the effectiveness of each MUE relaying;

The 3rd step: each MUE selects the FUE relay collection according to the order of sequence according to the effectiveness parameter;

The 4th step:, if exist FUE to be selected by a plurality of MUE, travel through all possible Selection and Constitute scheme, the long-pending maximum scheme of MUE effective increment is defined as optimal policy, and determines the relay selection set of each MUE according to described strategy.

Preferably, cooperation transmission mode in the described first step stipulates that each time slot is divided into the part α of three parts: MUE to the FUE broadcast data, the MUE of FUE side relays to and flies honeycomb access point FAP part (1-α) β, and FUE receives the MUE compensation for the part (1-α) (1-β) that passes own data.

Preferably, in described second step, the number that the note frequency spectrum is monopolized MUE in network is M, and the number of FUE is N, and note some MUE wherein are MUE _m, m=1,2 ... M, some FUE are FUE _n, n=1,2 ... N,, according to the transmission rate after relaying, calculate each FUE and help the value of utility of each MUE relaying, MUE _mSelect the FUE relay collection

The time effectiveness equal to employ separately relaying

Effective sum, calculate FUE _nFor MUE _mApart from d _m,n, obtain FUE _nFor MUE _mEffectiveness-distance product

Preferably, in described the 3rd step, each MUE is according to distance d _m,nAscending selection FUE, and calculate successively cumulative utility-distance product Each MUE finds a fulcrum μ that can evenly divide effectiveness in network-distance product summation _m, each MUE _mObtain a FUE relaying subset

Make

In cumulative utility-distance product of all FUE be not more than μ _m

Compared with prior art, the present invention has following beneficial effect:

In the frequency spectrum that has a plurality of FUE is monopolized network, instruct a plurality of MUE effectively to select FUE to assist relaying, take into account simultaneously the fairness between MUE, compare full permutation algorithm and have lower operand and performance preferably.

Description of drawings

By reading the detailed description of non-limiting example being done with reference to the following drawings, it is more obvious that other features, objects and advantages of the present invention will become:

Fig. 1 is flow chart of the present invention;

Fig. 2 is macrocellular of the present invention and flies the signal of honeycomb scene, and the contrast situation of MUE and the non-approach to cooperation of FUE (independent transmission) and approach to cooperation (MUE employs the FUE cooperating relay);

Fig. 3 is the result of MUE relay selection while adopting this method in certain example;

Fig. 4 is the result of MUE relay selection while adopting full ranking method in certain example;

Numerical value when when Fig. 5 adopts this method, the MUE effective increment is arranged optimum or random system of selection with employing is complete contrasts;

Fig. 6 is the impact long-pending on MUE average utility increment of FUE quantity.

Embodiment

The present invention is described in detail below in conjunction with specific embodiment.Following examples will help those skilled in the art further to understand the present invention, but not limit in any form the present invention.Should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, can also make some distortion and improvement.These all belong to protection scope of the present invention.

Referring to Fig. 1, macrocellular user MUE of the present invention selects to fly phone user FUE and assists the method for relaying to comprise the following steps:

Step 1, a plurality of MUE and a plurality of FUE form frequency spectrum and monopolize network, adopt the cooperation transmission mode between MUE, FUE, and the regulation time slot uses agreement.MBS and FAP all are connected to (step S01 in figure) on core net.

MBS, FAP and Covering domain thereof, system model such as Fig. 1 that a plurality of MUE and a plurality of FUE form.When MUE-FUE adopts modality for co-operation, each MUE/FUE time slot is divided into the hop α of three part: MUE to FUE, MUE relay portion (1-α) β of FUE side, and MUE compensation FUE is used for passing the part (1-α) (1-β) of own data.At MUE to FUE the transmission of data part, the peritropous FUE broadcast data of each MUE.Broadcast data adopts the mode of frequency division multiplexing, and each FUE receives only the data of corresponding frequency band.In the FUE relay portion, FUE adopts forward direction to amplify (AF, amplify and forward) mode, its data that receive of normalization, then according to the principle of first in first out, transfer data to FAP.

Step 2, calculating different FUE is effectiveness and the relevant parameter (step S02 in figure) of each MUE relaying.

Consider that all FUE in each MUE awareness network help the full detail of its relaying, such as through-put power, channel quality and noise level etc.The effectiveness of the different FUE MUE of side relayings is different, as FUE _nThe MUE of side _mThe effectiveness of relaying is

$U_m^n=\mathrm{\τ}{B}_n\log (1+\frac{{\left|{\mathrm{\α}}_{m,n}{h}_{m,n}{h}_{n,a}\right|}^2{P}_m}{{|1+{\mathrm{\α}}_{m,n}{h}_{n,a}|}^2{\mathrm{\σ}}^2}).$ Formula one

Wherein, τ=α (1-α) β is the time coefficient after cooperation, B _nFUE _nThe bandwidth during MUE of side relaying, α _m,nThe normalization factor of FUE section, h _m,n, h _n,aRespectively MUE _mTo FUE _nAnd FUE _nTo the channel gain of FAP, P _mMUE _mThrough-put power.Here we suppose that noise is additive white Gaussian noise, and its variance is σ ²Because adopting frequency division multiplexing mode and FUE, MUE takies independently channel, MUE when the relay transmission _mIn the FUE relay collection

Under effectiveness equal to employ separately relaying

Effective sum:

Formula two

For balance individual interest and whole fairness, we propose to receive assorted bargaining solution for the relay selection problem, that is:

Formula three

Wherein

It is the FUE set A kind of may cutting apart, U _mTo cut off MUE in this minute _mEffectiveness.d _mMUE when bargaining unsuccessfully _mEffectiveness, be equal to MUE at this _mData transfer rate while directly to MBS, transmitting:

$d_m=B_m\log (1+\frac{{\left|h_{m,b}\right|}^2{P}_m}{{\mathrm{\σ}}^2})$ Formula four

B wherein _mMUE _mBandwidth while directly transmitting, h _m,bMUE _mChannel gain to MBS.

Each MUE calculates arbitrary FUE according to formula one _nHelp the effectiveness of its relaying

In European how much categories, the bargaining game can be expressed with the space game.Calculate each FUE _nFor MUE _mApart from d _m,n:

$d_{m,n}=\frac{1/U_m^n}{\underset{m}{\mathrm{\Σ}}(1/U_m^n)}.$ Formula five

Be similar to the concept of the moment in lever system, we obtain arbitrary relaying FUE _nFor MUE _mEffectiveness-distance product:

${\mathrm{\φ}}_m^n=U_m^n\·d_{m,n}.$ Formula six

Step 3, each MUE selects FUE relay collection (step S03 in figure) according to the order of sequence according to parameter.

Each MUE is according to distance d _m,nAscending selection FUE, and calculate successively cumulative utility-distance product, namely apart from MUE _mLess than FUE _nThe effectiveness-distance product sum of all FUE:

Formula seven

Be analogous to lever system, each MUE need to find the fulcrum that can evenly divide effectiveness in network-distance product summation, and this fulcrum meets:

Formula eight

Each MUE determines its position of the fulcrum according to following formula.So each MUE _mObtain a FUE relaying subset

, make

Cumulative utility-distance product of middle FUE is not more than μ _m, that is:

Formula nine

Step 4,, if exist FUE to be selected by a plurality of MUE, travel through all possible Selection and Constitute scheme, and optimal policy is the long-pending maximum scheme (step S04 in figure) of MUE effective increment.

The long-pending P_UG of definition maximum utility increment ^*=0.Belong to more than one for any FUE

Enumerate all possible segmentation combination, circulation:

Calculate the current long-pending P_UG of effective increment of cutting apart in situation.

If P_UG〉P_UG ^*, make P_UG ^*=P_UG, and renewal optimal policy is current dividing method.

Circulate complete

Finally, each MUE determines that according to optimal policy its relaying choice set closes

As shown in Figure 2, be macrocellular of the present invention and fly honeycomb scene schematic diagram.Wherein three MUE(and FUE) adopt non-modality for co-operation, three MUE(and FUE) adopt modality for co-operation.

In non-modality for co-operation, MUE utilizes whole time slot directly to MBS, to pass data, and FUE must wait for.In modality for co-operation, the front α part MUE of each time slot is to the FUE broadcasting transmitting, and ensuing (1-α) beat portion FUE MUE of side relay data is to FAP, and own data are transmitted in the MUE compensation that last (1-α) (1-β) part FUE uses.

Fig. 3 to Fig. 6 is result and the parameter comparison of multiple relay selection method under certain example.

The environmental parameter of this example is:

It is in 1 * 1 square geographical regional extent of starting point that 6 MUE and 9 FUE are evenly distributed in (0,0), MBS in (2,2) and FAP in (0.5,0.5).To be 10, FUE transmission bandwidth obtained by the bandwidth of even segmentation service MUE the transmission bandwidth of each MUE.Through-put power P _m=1, noise level σ ²=1, parameter alpha=0.5, parameter beta=0.5.Usually, each the transmission pair between channel gain and their spacing be inversely proportional to.For the transmission quality between outstanding FUE-FAP, the channel gain between them is multiplied by 0 to 10 equally distributed factor.Except this method, this example has also been considered two kinds of control methods: full ranking method and random choice method.Full ranking method refers to travel through all possible Selection and Constitute scheme for the assorted bargaining solution of receiving in formula three, finds maximum MUE effective increment long-pending, and selection scheme corresponding to record is optimal policy.Due to all combinations of traversal, the higher (M of computation complexity of full ranking method ^NInferior).Random choice method refers to be randomly each MUE distribution relay collection, therefore only needs primary distribution to get final product.

Fig. 3 and Fig. 4 have contrasted the Different Results of MUE relay selection under this method and full ranking method.Under this method, MUE ₂, MUE ₃And MUE ₄The FUE relaying number of selecting is respectively 2,2 and 2; And MUE under full ranking method ₂, MUE ₃And MUE ₄The FUE relaying number of selecting is respectively 1,2 and 3.MUE ₁, MUE ₅And MUE ₆Relay selection under two kinds of methods is in full accord.

While as shown in Figure 5, adopting distinct methods, the effectiveness of each MUE has notable difference.MUE under this method ₂Effective increment higher than full ranking method, MUE under full ranking method ₃And MUE ₄Effective increment higher than this method, and MUE under this method ₁, MUE ₅And MUE ₆Effective increment be equal to full ranking method.Yet for random choice method, because MUE ₁Obtained too much FUE and assisted, thus higher effective increment is arranged, and MUE ₂To MUE ₆Effective increment be negative value.

, by changing respectively the quantity of FUE, also tested the impact long-pending on the MUE effective increment of this parameter in the present embodiment.As shown in Figure 6, fixedly the quantity of MUE is 4, and the quantity that makes FUE rises to 9 from 4, obtains the long-pending curve with the FUE number change of MUE average utility increment under three kinds of methods.For example in figure coordinate be (6,0.59) representative be respectively 4 and 6, MUE average utility increment is long-pending is about 0.59 when the quantity of MUE, FUE.In figure profitable result be all the average of the result that obtains by 100 repeated experiments.

When the quantity growth of FUE, the MUE effective increment under this method and full ranking method is long-pending all to be increased to some extent.Quantity at FUE reached before 5, and the growth rate of this method is slower, and remarkable increase is arranged afterwards.When the quantity of FUE is increased to after 5, under this method and full ranking method, the long-pending gap of MUE effective increment is constantly dwindled.When 9 FUE are arranged, long-pending 90% of the full ranking method that approximately reaches of the MUE effective increment of this method.And for random choice method, its MUE effective increment is long-pending hovers all the time near 0.

Above specific embodiments of the invention are described.It will be appreciated that, the present invention is not limited to above-mentioned particular implementation, and those skilled in the art can make various distortion or modification within the scope of the claims, and this does not affect flesh and blood of the present invention.

Claims (4)

1. a macrocellular user MUE selects to fly phone user FUE and assists the method for relaying, it is characterized in that, comprises the steps:

The first step: a plurality of MUE and a plurality of FUE take the cooperation transmission mode, and regulation time slot allocation agreement;

Second step: calculating different FUE is the effectiveness of each MUE relaying;

The 3rd step: each MUE selects the FUE relay collection according to the order of sequence according to the effectiveness parameter;

The 4th step:, if exist FUE to be selected by a plurality of MUE, travel through all possible Selection and Constitute scheme, the long-pending maximum scheme of MUE effective increment is defined as optimal policy, and determines the relay selection set of each MUE according to described optimal policy.

2. macrocellular user MUE according to claim 1 selects to fly phone user FUE and assists the method for relaying, it is characterized in that: the cooperation transmission mode in the described first step stipulates that each time slot is divided into the part α of three parts: MUE to the FUE broadcast data, FUE helps MUE to relay to part (1-α) β that flies honeycomb access point FAP, and FUE receives the MUE compensation for the part (1-α) (1-β) that passes own data, wherein, α, β are parameter.

3. macrocellular user MUE according to claim 1 selects to fly phone user FUE and assists the method for relaying, it is characterized in that: in described second step, the number that the note frequency spectrum is monopolized MUE in network is M, and the number of FUE is N, and note some MUE wherein are MUE _m, m=1,2 ... M, some FUE are FUE _n, n=1,2 ... N,, according to the transmission rate after relaying, calculate each FUE and help the value of utility of each MUE relaying, MUE _mSelect FUE relay collection N _mThe time effectiveness equal to employ separately relaying FUE _n(n ∈ N _m) effective sum, calculate FUE _nFor MUE _mApart from d _m,n, obtain FUE _nFor MUE _mEffectiveness-distance product

4. macrocellular user MUE according to claim 1 selects to fly phone user FUE and assists the method for relaying, it is characterized in that: in described the 3rd step, each MUE is according to distance d _m,nAscending selection FUE, and calculate successively cumulative utility-distance product

Each MUE finds a fulcrum μ that can evenly divide effectiveness in network-distance product summation _m, each MUE _mObtain a FUE relaying subset C _m, make C _mIn cumulative utility-distance product of all FUE be not more than μ _m

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