CN105611572A - Reconfiguration method and reconfiguration system of relay subframes - Google Patents

Abstract

The invention relates to a reconfiguration method and a reconfiguration system of relay subframes, belonging to the technical field of wireless communication. The method comprises the following steps of: predicting traffic of an eNodeB and a Relay of next subframe adjusting period according to change conditions of the traffic of the eNodeB and the relay of former N subframe adjusting periods; and judging whether to increase a Un subframe or reduce the Un subframe according to the predicted traffic of a DeNB and the relay of the next subframe adjusting period, and performing reconfiguration for RN subframes according to the result, when increase of the subframes is required, selecting a subframe configuration mode capable of increasing the number of the subframes from Un subframe configuration modes corresponding to uplink and downlink configuration modes of a DeNB cell, and when decrease of the subframes is required, selecting the subframe configuration mode capable of decreasing the number of the subframes from the Un subframe configuration modes corresponding to the uplink and downlink configuration modes of the DeNB cell. Thus, configuration modes of the subframes can be adjusted according to the traffic, a problem of data congestion caused by unreasonable subframe configuration is avoided. The method and the system provided by the invention are simple and practicable, are easy to realize in engineering, and improve performance of relay nodes.

Description

A kind of method for reconfiguration of relay sub-frame and system

Technical field

The method for reconfiguration and the system that the present invention relates to a kind of relay sub-frame, belong to wireless communication technology field.

Background technology

Relaying technique as a kind of emerging technology, has caused more and more widely and has paid attention to, has been regarded as the key of B3G/4GTechnology, in wireless communication system, in order to increase coverage or focus business to be provided, is used relaying technique to become importantTechnological means. As shown in Figure 1, via node (RN, RelayNode) is connected to the eNodeB of its ownership by wireless modeCommunity, introduces after RN, and the back haul link between the eNodeB (Donor, DeNB) of RN and its ownership becomes Un interface. At Type1In relaying, Un interface uses identical carrier resource with Uu interface, for avoiding producing and disturb between Un interface and Uu mouth, two chainsRoad adopts time division way work. 19 kinds of Un sub-frame allocation sides that configured by high-level signaling by DeNB are provided in 3GPP standardFormula, as shown in table 1. In existing standard, only provide 19 kinds of configuration modes of Un subframe, but according to which kind of method, How to choose is joinedDo not put and specifically provide, if Un subframe is reshuffled irrational words, must cause the congested of data, affect relay systemEnergy.

Summary of the invention

The object of this invention is to provide a kind of method for reconfiguration and system of relay sub-frame, to solve the sub-frame configuration due to RNThe unreasonable problem that causes data congestion.

The present invention is for solving the problems of the technologies described above the method for reconfiguration that a kind of relay sub-frame is provided, this method for reconfiguration bagDraw together following steps:

1) according to top n subframe adjustment cycle DeNB and RN portfolio situation of change, the prediction next son framing control cycleDeNB and RN portfolio;

2) judge whether to increase Un according to the DeNB in next son framing control cycle and the portfolio of Relay that dopeSubframe or minimizing Un subframe, and according to result, RN subframe is reshuffled.

In the time that needs increase subframe, current subframe mode is adjusted into RN corresponding to DeNB community uplink-downlink configuration modeThe sub-frame configuration mode that in frame configuration mode, number of sub-frames increases; In the time that needs reduce subframe, current subframe mode is adjusted intoThe sub-frame configuration mode that in RN sub-frame configuration mode corresponding to DeNB community uplink-downlink configuration mode, number of sub-frames reduces.

Described step 1) in the DeNB portfolio in next son framing control cycle of doping be the business of current period DeNBAmount adds the mean value that top n subframe adjustment cycle DeNB portfolio changes, the RN industry in the next son framing control cycle dopingBusiness amount is that the portfolio of current period RN adds the mean value that top n subframe adjustment cycle RN portfolio changes.

For descending sub frame, described step 2) in increase subframe criterion be:

$T_{eNodeB}^{\′}+{\widetilde{\mathrm{\Δ}}}_{eNodeB}>T_{max-eNodeB}$

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}<\mathrm{\&alpha;}*T_{max-relay}$

Wherein, T '_eNodeBAnd T '_relayBe respectively DeNB and the RN downlink traffic of current period,WithBe respectively the mean value that top n subframe adjustment cycle DeNB and RN downlink traffic change, T_max-eNodeBThat DeNB isThe buffer traffic peak that via node distributes, T_max-relayBe RN down buffer storage device traffic peak, what α was buffer facesBoundary's ratio, 0 < α < 1.

For descending sub frame, described step 2) in reduce subframe criterion be:

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}>T_{max-relay}$

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}<\mathrm{\&alpha;}*T_{max-eNodeB}$

Wherein, T '_eNodeBAnd T '_relayBe respectively DeNB and the RN downlink traffic of current period,WithBe respectively the mean value that top n subframe adjustment cycle DeNB and RN downlink traffic change, T_max-eNodeBThat DeNB isThe buffer traffic peak that via node distributes, T_max-relayBe RN down buffer storage device traffic peak, what α was buffer facesBoundary's ratio, 0 < α < 1.

Described step 2) in be that DeNB carries out the adjustment of RN subframe according to court verdict, and by RRC signaling, RN is reshuffledMessage sends to RN, completes subframe and reshuffles, and complete by RRC signaling DeNB reprovision at RN.

The present invention also provides a kind of reconfiguration system of relay sub-frame, and this reconfiguration system comprises prediction module and judgementAdjusting module,

Described prediction module is used for according to top n subframe adjustment cycle DeNB and RN portfolio situation of change, under predictionThe DeNB of one subframe adjustment cycle and RN portfolio;

The DeNB in next son framing control cycle and the business of Relay that described judgement adjusting module dopes for basisAmount judges whether to increase subframe or reduces subframe, and according to result, RN subframe is reshuffled.

Described judgement adjusting module, judging need to increase subframe time, is adjusted into current subframe mode on DeNB communityThe sub-frame configuration mode that in RN sub-frame configuration mode corresponding to downstream arrangements mode, number of sub-frames increases; Need to reduce when judgingWhen subframe, current subframe mode is adjusted into subframe in RN sub-frame configuration mode corresponding to DeNB community uplink-downlink configuration modeThe sub-frame configuration mode that number reduces.

For descending sub frame, describedly judge that adjusting module for increasing the criterion of subframe is:

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}>T_{max-eNodeB}$

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}<\mathrm{\&alpha;}*T_{max-relay}$

Wherein, T '_eNodeBAnd T '_relayBe respectively DeNB and the RN downlink traffic of current period,WithBe respectively the mean value that top n subframe adjustment cycle DeNB and RN downlink traffic change, T_max-eNodeBThat DeNB isThe buffer traffic peak that via node distributes, T_max-relayBe RN down buffer storage device traffic peak, what α was buffer facesBoundary's ratio, 0 < α < 1.

For descending sub frame, describedly judge that adjusting module for reducing the criterion of subframe is:

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}>T_{max-relay}$

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}<\mathrm{\&alpha;}*T_{max-eNodeB}$

Wherein, T '_eNodeBAnd T '_relayBe respectively DeNB and the RN downlink traffic of current period,WithBe respectively the mean value that top n subframe adjustment cycle DeNB and RN downlink traffic change, T_max-eNodeBThat DeNB isThe buffer traffic peak that via node distributes, T_max-relayBe RN down buffer storage device traffic peak, what α was buffer facesBoundary's ratio, 0 < α < 1.

The invention has the beneficial effects as follows: the present invention changes according to top n subframe adjustment cycle eNodeB and Relay portfolioSituation, the portfolio of prediction next son framing control cycle eNodeB and Relay, according to the next son framing control cycle dopingThe portfolio of DeNB and Relay judges whether to increase Un subframe or reduces Un subframe, and according to result, RN subframe is carried outReshuffle, in the time that needs increase subframe, according to choosing in Un sub-frame configuration mode corresponding to DeNB community uplink-downlink configuration modeThe sub-frame configuration mode that number of sub-frames increases, in the time that needs reduce subframe, corresponding according to DeNB community uplink-downlink configuration modeIn Un sub-frame configuration mode, choose the sub-frame configuration mode that number of sub-frames reduces, thereby realize the configuration to subframe according to portfolioMode is adjusted, and has avoided the problem of the data congestion unreasonable caused due to sub-frame configuration, and the method is simple, workIn journey, be easy to realize, improved the performance of via node.

Brief description of the drawings

Fig. 1 is the connection diagram of via node RN;

Fig. 2 is RN configuration schematic diagram;

Fig. 3 is relay sub-frame configuration flow chart.

Detailed description of the invention

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

The embodiment of the method for reconfiguration of a kind of relay sub-frame of the present invention

Because Un interface in Type1 relaying and Uu interface need time-division work, so DeNB need to be Type1 link deploymentUn subframe, so that RN determines the time of carrying out data transmit-receive on Un interface, the start-up course of RN can be divided into two stages,First stage, RN accesses network, and is connected to OAM system downloads initial configuration parameter. In the second stage of RN start-up course andAfter, DeNB can use RN reconfiguration course to carry out reprovision to Un mouth parameter, as shown in Figure 2.

Un sub-frame configuration mode from current 19, carries out subframe according to portfolio and reshuffles mainly for Un descendingThe increase of subframe or minimizing, therefore the present embodiment describes with the adjustment of Un descending sub frame, but that the present invention is not only limited to is descending. ThisEmbodiment subframe reconfiguration course is as shown in Figure 3: concrete configuration step is as follows:

1.DeNB is by operation management maintain (OperationAdministrationandMaintenance, OAM)System acquisition DeNB community uplink-downlink configuration mode and sub-frame configuration mode.

2. start via node RN, adopt common UE attaching process to access network, obtain initial configuration.

3. set Un subframe adjustment cycle, judge whether to reach Un subframe adjustment cycle, if reach, adjust according to Un subframeWhole criterion is adjusted.

The DeNB portfolio in next son framing control cycle is that the portfolio of current period DeNB adds top n subframe adjustment weekThe mean value that phase DeNB portfolio changes, the RN portfolio in the next son framing control cycle doping is the business of current period RNAmount adds the mean value that top n subframe adjustment cycle RN portfolio changes.

The DeNB of current period T and the variation of RN downlink traffic are respectively Δ_eNodeBAnd Δ_relay,

Δ_eNodeB＝T′_eNodeB-T_eNodeBΔ_relay＝T′_relay-T_relay

Wherein T '_eNodeB、T′_relayBe respectively DeNB and the RN downlink traffic of current period T, T_eNodeB、T_relayFor upper oneThe DeNB of cycle T and RN downlink traffic, in like manner can calculate top n subframe adjustment cycle DeNB and the quantitative change of RN downlink businessThe mean value of changing is respectivelyWithRelaying is by buffer status report (BufferStatus shown in table 2Reports, BSR) instruction downlink traffic is reported to DeNB. ENodeB is by the DeNB of prediction next son framing control cycle TWith RN downlink traffic, carry out subframe adjustment, if:

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}<\mathrm{\&alpha;}*T_{max-relay}$

Increase Un descending sub frame; Wherein, T_max-eNodeBThat DeNB is the buffer traffic peak that via node distributes,T_max-relayRN down buffer storage device traffic peak, the aritical ratio that α is buffer, 0 < α < 1.

If:ReduceUn descending sub frame, otherwise subframe does not adjust.

Table 1

Table 2

4.DeNode carries out the adjustment of Un subframe according to subframe court verdict, and by RRC signaling, RN reconfiguration message is sent outGive RN, in the time that needs increase subframe, current subframe mode is adjusted into RN corresponding to DeNB community uplink-downlink configuration modeThe sub-frame configuration mode that in frame configuration mode, number of sub-frames increases; In the time that needs reduce subframe, current subframe mode is adjusted intoThe sub-frame configuration mode that in RN sub-frame configuration mode corresponding to DeNB community uplink-downlink configuration mode, number of sub-frames reduces. RN completesSubframe is reshuffled, and completes by RRC signaling eNodeB reprovision.

Example 1

Describe as an example of a certain concrete OAM system example below, suppose that the up-downgoing of this OAM system DeNB cell initial joinsThe mode of putting is that 1, Un subframe initial configuration mode is 0, and it is 1s that subframe is reshuffled cycle T, the descending via node of distributing to of DeNBThe maximum of T of buffer_max-eNodeBFor 3000000bytes, the descending buffer maximum of T of RN_max-relayFor 250990bytes,Buffer aritical ratio α is 75%.

1.DeNB is by operation management maintain (OperationAdministrationandMaintenance, OAM)System obtains sub-frame configuration mode, and DeNB cell initial uplink-downlink configuration mode is that 1, Un subframe initial configuration mode is 0, subframeReshuffling cycle T is 1s.

2.RN starts, and adopts common UE attaching process to access network, and obtaining Un subframe initial configuration mode is 0.

3. whether current time arrives Un subframe adjustment cycle, sentences if arrival subframe adjustment cycle carries out subframe adjustmentDetermine, otherwise finish.

If 4. subframe adjustment cycle arrives, adjust criterion according to Un subframe and adjust, suppose current period eNodeBBe transferred to relaying downlink traffic T '_eNodeBFor 2439678bytes, RN downlink traffic is reported and is designated as 25 by BSR,1162＜T′_relay≤ 1429, get N=5, it is average that front 5 sub-framing control cycle eNodeB and Relay downlink traffic changeValue Can be calculated next son framing control cycle eNodeB andThe downlink traffic predicted value of Relay is respectively 3145334bytes and 4086,

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}>T_{max-eNodeB}$

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}<\mathrm{\&alpha;}*T_{max-relay}$

Increase Un descending sub frame.

5.DeNode carries out the adjustment of Un subframe according to the 4th step frame court verdict, by Un sub-frame configuration mode by 0 adjustmentBe 2, and by RRC signaling, RN reconfiguration message sent to RN.

6.RN completes Un sub-frame configuration mode and changes, and subframe reprovision is set to 2, and heavy by RRC signaling eNodeBJoin.

Example 2

Suppose that OAM system DeNB cell initial uplink-downlink configuration mode is that 1, Un subframe initial configuration mode is 3, subframe weightConfiguration cycle T is 1s, the descending maximum of T of distributing to via node buffer of DeNB_max-eNodeBFor 3000000bytes, under RNRow buffer maximum of T_max-relayFor 250990bytes, buffer aritical ratio α is 75%

1.DeNB is by operation management maintain (OperationAdministrationandMaintenance, OAM)System obtains sub-frame configuration mode, and DeNB cell initial uplink-downlink configuration mode is that 1, Un subframe initial configuration mode is 3, subframeReshuffling cycle T is 1s.

2.RN starts, and adopts common UE attaching process to access network, and obtaining Un subframe initial configuration mode is 3.

3. whether current time arrives Un subframe adjustment cycle, sentences if arrival subframe adjustment cycle carries out subframe adjustmentDetermine, otherwise finish.

If 4. subframe adjustment cycle arrives, adjust criterion according to Un subframe and adjust, suppose current period eNodeBBe transferred to relaying downlink traffic T '_eNodeBFor 134986bytes, RN downlink traffic is reported and is designated as 49 by BSR,165989<T′_relay≤ 204111, get N=5, it is flat that front 5 sub-framing control cycle eNodeB and Relay downlink traffic changeAverage $\begin{array}{cc}{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}=89272bytes& {\stackrel{\&CenterDot;}{\mathrm{\&Delta;}}}_{relay}=109774bytes,\end{array}$ Can be calculated

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}>T_{max-relay}$

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}<\mathrm{\&alpha;}*T_{max-eNodeB}$

Reduce Un descending sub frame

5.DeNode carries out the adjustment of Un subframe according to the 4th step frame court verdict, and Un sub-frame configuration is adjusted into 1 by 3,And by RRC signaling, RN reconfiguration message is sent to RN.

6.RN completes Un sub-frame configuration mode and changes, and subframe reprovision is set to 1, and heavy by RRC signaling eNodeBJoin.

The embodiment of the reconfiguration system of a kind of relay sub-frame of the present invention

Simultaneously the present invention also provides a kind of reconfiguration system of relay sub-frame, this reconfiguration system comprise prediction module andJudge adjusting module, wherein prediction module, for according to top n subframe adjustment cycle DeNB and RN portfolio situation of change, is predictedThe DeNB in next son framing control cycle and RN portfolio; Judge the next son framing control cycle that adjusting module dopes for basisDeNB and the portfolio of Relay judge whether to increase subframe or reduce subframe, and according to result, RN subframe is carried out to weightConfiguration. The detailed description of the invention of each module is illustrated in the embodiment of method, repeats no more here.

The present invention, according to top n subframe adjustment cycle eNodeB and Relay downlink traffic situation of change, predicts next sonThe downlink traffic of framing control cycle eNodeB and Relay, according to DeNB and the Relay in the next son framing control cycle dopingPortfolio judge whether to increase Un subframe or reduce Un subframe, and according to result, RN subframe is reshuffled, work as needWhile increasing subframe, increase according to choosing number of sub-frames in Un sub-frame configuration mode corresponding to DeNB community uplink-downlink configuration modeSub-frame configuration mode, in the time that needs reduce subframe, the Un sub-frame configuration side corresponding according to DeNB community uplink-downlink configuration modeIn formula, choose the sub-frame configuration mode that number of sub-frames reduces, the configuration mode of subframe adjusted according to portfolio thereby realize,The problem of having avoided the data congestion unreasonable caused due to sub-frame configuration, the method is simple, is easy to realize in engineering.

Claims (10)

1. a method for reconfiguration for relay sub-frame, is characterized in that, this method for reconfiguration comprises the following steps:

1) according to top n subframe adjustment cycle DeNB and RN portfolio situation of change, the DeNB in prediction next son framing control cycleWith RN portfolio;

2) judge whether to increase Un subframe according to the DeNB in next son framing control cycle and the portfolio of Relay that dopeOr reduce Un subframe, and according to result, RN subframe is reshuffled.

2. the method for reconfiguration of relay sub-frame according to claim 1, is characterized in that, in the time that needs increase subframe, and willCurrent subframe mode is adjusted into that number of sub-frames in RN sub-frame configuration mode corresponding to DeNB community uplink-downlink configuration mode increasesSub-frame configuration mode; In the time that needs reduce subframe, current subframe mode is adjusted into DeNB community uplink-downlink configuration mode correspondenceRN sub-frame configuration mode in number of sub-frames reduce sub-frame configuration mode.

3. the method for reconfiguration of relay sub-frame according to claim 2, is characterized in that, described step 1) in dopeThe DeNB portfolio in next son framing control cycle is that the portfolio of current period DeNB adds top n subframe adjustment cycle DeNB industryThe mean value of business quantitative change, the RN portfolio in the next son framing control cycle doping is that the portfolio of current period RN adds and goes forwardN the mean value that sub-framing control cycle RN portfolio changes.

4. the method for reconfiguration of relay sub-frame according to claim 2, is characterized in that, for descending sub frame, and instituteState step 2) in increase the criterion of subframe and be:

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}>T_{\max -eNodeB}$

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}<\mathrm{\&alpha;}*T_{max-relay}$

Wherein, T '_eNodeBAnd T '_relayBe respectively DeNB and the RN downlink traffic of current period,WithRespectivelyFor the mean value of top n subframe adjustment cycle DeNB and the variation of RN downlink traffic, T_max-eNodeBThat DeNB is that via node dividesThe buffer traffic peak of joining, T_max-relayRN down buffer storage device traffic peak, the aritical ratio that α is buffer, 0 < α <1。

5. the method for reconfiguration of relay sub-frame according to claim 2, is characterized in that, for descending sub frame, described inStep 2) in reduce the criterion of subframe and be:

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}>T_{max-relay}$

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}>\mathrm{\&alpha;}*T_{\max -eNodeB}$

Wherein, T '_eNodeBAnd T '_relayBe respectively DeNB and the RN downlink traffic of current period,WithRespectivelyFor the mean value of top n subframe adjustment cycle DeNB and the variation of RN downlink traffic, T_max-eNodeBThat DeNB is that via node dividesThe buffer traffic peak of joining, T_max-relayRN down buffer storage device traffic peak, the aritical ratio that α is buffer, 0 < α <1。

6. according to the method for reconfiguration of the relay sub-frame described in claim 4 or 5, it is characterized in that described step 2) in beDeNB carries out the adjustment of RN subframe according to court verdict, and by RRC signaling, RN reconfiguration message is sent to RN, completes son at RNFrame is reshuffled, and completes by RRC signaling DeNB reprovision.

7. a reconfiguration system for relay sub-frame, is characterized in that, this reconfiguration system comprises prediction module and judgement adjustmentModule,

Described prediction module, for according to top n subframe adjustment cycle DeNB and RN portfolio situation of change, is predicted next sonThe DeNB in framing control cycle and RN portfolio;

Described judgement adjusting module is for sentencing according to the DeNB in next son framing control cycle and the portfolio of Relay that dopeBreak and whether need to increase subframe or reduce subframe, and according to result, RN subframe is reshuffled.

8. the reconfiguration system of relay sub-frame according to claim 7, is characterized in that, described judgement adjusting module is being sentencedBreak and need to increase subframe time, current subframe mode is adjusted into RN sub-frame configuration corresponding to DeNB community uplink-downlink configuration modeThe sub-frame configuration mode that in mode, number of sub-frames increases; When judging need to reduce subframe time, current subframe mode is adjusted intoThe sub-frame configuration mode that in RN sub-frame configuration mode corresponding to DeNB community uplink-downlink configuration mode, number of sub-frames reduces.

9. the reconfiguration system of relay sub-frame according to claim 8, is characterized in that, for descending sub frame, described inJudge that adjusting module for the criterion that increases subframe is:

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}>T_{\max -eNodeB}$

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}<\mathrm{\&alpha;}*T_{max-relay}$

Wherein, T '_eNodeBAnd T '_relayBe respectively DeNB and the RN downlink traffic of current period,WithRespectivelyFor the mean value of top n subframe adjustment cycle DeNB and the variation of RN downlink traffic, T_max-eNodeBThat DeNB is that via node dividesThe buffer traffic peak of joining, T_max-relayRN down buffer storage device traffic peak, the aritical ratio that α is buffer, 0 < α <1。

10. the reconfiguration system of relay sub-frame according to claim 8, is characterized in that, for descending sub frame, described inJudge that adjusting module for the criterion that reduces subframe is:

$T_{relay}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{relay}>T_{max-relay}$

$T_{eNodeB}^{\&prime;}+{\widetilde{\mathrm{\&Delta;}}}_{eNodeB}>\mathrm{\&alpha;}*T_{\max -eNodeB}$

Wherein, T '_eNodeBAnd T '_relayBe respectively DeNB and the RN downlink traffic of current period,WithRespectivelyFor the mean value of top n subframe adjustment cycle DeNB and the variation of RN downlink traffic, T_max-eNodeBThat DeNB is that via node dividesThe buffer traffic peak of joining, T_max-relayRN down buffer storage device traffic peak, the aritical ratio that α is buffer, 0 < α <1。