CN103428796B - In handoff procedure, determine method and the device of target BS - Google Patents

Abstract

The invention discloses method and the device of in a kind of handoff procedure, determining target BS. The method comprises: according to the Reference Signal Received Power measured value threshold value setting in advance, grade classification is carried out in alternative target base station corresponding to Reference Signal Received Power measured value comprising in the measurement reporting information receiving; Obtain the alternative target group of base stations that the highest grade, send handover request message to this alternative target group of base stations; For the alternative target base station of having fed back handover request ack message, according to the switching priority computing formula setting in advance, calculate its priority factors value, using the highest priority be that alternative target base station corresponding to factor values is as target BS, the alternative target base station of having returned to handover request ack message to other sends handover cancelling message, and notice is cancelled this handoff procedure. Application the present invention, the decline that can as far as possible avoid having switched rear user satisfaction.

Description

In handoff procedure, determine method and the device of target BS

Technical field

The present invention relates to handoff technique, particularly in a kind of handoff procedure determine target BS method andDevice.

Background technology

In long-term evolution plan (LTE, LongTermEvolved) system, RRM is carriedThe function that supplies the RRM of air interface, object is that some mechanism air interfaces can be providedEffective utilization, realize optimum resource utilization, thereby meet the defined wireless money of LTE systemThe demand that source is relevant. Wherein, the mobile management in RRM, for realizing LTE systemMobility in supporting cellular network, comprises the mobility pipe under LTE free time (LTE_IDLE) stateReason and LTE activate the mobile management under (LTE_ACTIVE) state. Wherein, LTE_ACTIVEMobile management under state shows as switching, subscriber equipment (UE, UserEquipment) forImprove communication quality, need between each base station (eNB), switch, below with existing LTESystem switches to example by X2 interface and introduces handoff procedure, and in handoff procedure, source eNB needsThe measurement reporting according to UE reports (MeasurementReport) information, for UE determines target eNBAnd notify UE, so that UE is switched to target eNB from source eNB.

Fig. 1 is that in existing LTE system, UE carries out the schematic flow sheet switching. Referring to Fig. 1, this flow processComprise:

Step 101, in the time that satisfied measurement reports triggering criterion, UE sends to measure to source eNB and notifiesBreath;

In this step, measure reporting information and mainly comprise: the Reference Signal Received Power of this community (RSRP,ReferenceSignalReceivedPower) the RSRP measured value information of measured value information, adjacent cell,Wherein, the RSRP measured value information of adjacent cell needs to determine alternative target eNB after being used for.

Measurement reports triggering criterion to be issued to each UE by LTE system by system message, if UE surveysMeasure satisfied measurement of the RSRP measured value of Dao Zhe community and the RSRP measured value of adjacent cell and report triggeringEvent criteria, carries out the process that reports of measuring.

Step 102, the measurement reporting information of source eNB based on receiving and the switch decision calculation setting in advanceMethod, for UE selects alternative target eNB, and sends handover request to the alternative target eNB selecting(HANDOVERREQUEST) message;

In this step, in HANDOVERREQUEST message, carry the contextual information of UE,The contextual information of UE mainly comprises: the QoS information of the current all business of UE, the security capabilities of UEInformation and AS security information etc.

Measurement reporting information and the switch decision algorithm of source eNB based on receiving, for UE selects alternative orderMark eNB specifically comprises following two kinds of technical schemes:

A, source eNB, from the RSRP measured value information receiving, choose the highest correspondence of RSRP measured valueENB as alternative target eNB; Or

B, source eNB, from the RSRP measured value information receiving, choose all switch decision algorithms that meetENB corresponding to RSRP measured value as alternative target eNB, like this, the number of alternative target eNBAmount can be one or more.

Step 103, alternative target eNB receives handover request message, determines and receives UE, will switch lifeOrder is carried at switching request response (HANDOVERREQUESTACKNOWLEDGE) messageIn, send to source eNB;

In this step, alternative target eNB, according to the resource situation of self, judges whether to meet to switch and asksAsk the UE carrying in message to wish the business need of setting up in target eNB, as long as one of them businessQoS demand can meet, and receives UE, and is UE distribution cell-radio network temporary indentification(C-RNTI, CellRadioNetworkTemporaryIdentity) and switch relevant configuration ginsengNumber, inserts in switching command.

Switching relevant configuration parameter comprises: the physics of Radio Resource common configuration information, target eNBID, system up-downgoing carrier bandwidths information, and random access resource information.

As previously mentioned, for source eNB choose RSRP measured value the eNB of high correspondence as alternative orderThe situation of mark eNB, if this alternative target eNB receives after handover request message, can not meet UEThe business need of building, return to switch to source eNB and prepare unsuccessfully (HANDOVERPREPARATIONFAILURE) message, shows to receive this UE, and source eNB receives HANDOVERPREPARATIONFAILURE message, from the RSRP measured value information receiving, chooses RSRPThe eNB of measured value time high correspondence, as new alternative target eNB, sends out to this new alternative target eNBAlternative target eNB send handover request message, until can return to HANDOVERREQUESTACKNOWLEDGE message.

Choosing all eNB corresponding to RSRP measured value that meet switch decision algorithm for source eNB doesFor the situation of alternative target eNB, all alternative target eNB that meet switch decision algorithm will be to source eNBReturn to HANDOVERREQUESTACKNOWLEDGE message or HANDOVERPREPARATIONFAILURE message, receives this UE or does not receive this UE showing.

In practical application, alternative target eNB not only can use according to the load of community self and resourceSituation, it is current whether judgement can meet the UE carrying in HANDOVERREQUEST messageThrough setting up the qos requirement of business, can also be in the time having available non-competing random access resource, provide non-Competition random access resource information, and this non-competing random access resource information is filled into switching commandIn.

Step 104, source eNB receives handover request ack message, determines target eNB;

In this step, sequentially send the situation of handover request message to alternative target eNB for source eNB,If receive HANDOVERREQUESTACKNOWLEDGE message, by transmission, this disappearsThe alternative target eNB of breath is as target eNB.

Choosing all eNB corresponding to RSRP measured value that meet switch decision algorithm for source eNB doesFor the situation of alternative target eNB, source eNB can select to reply at first HANDOVERREQUESTThe alternative target eNB of ACKNOWLEDGE message is as target eNB.

Above-mentioned steps 101, to step 104, is the flow process of determining target eNB in handoff procedure, switchesPreparatory stage.

Determining after target BS, just UE can be switched to target eNB from source eNB, carry out asLower step.

Step 105, passes through UE by the handover request ack message of target eNB, and UE is according to switchingRequest response, initiates access at random, starts the uplink synchronous process with target eNB;

In this step, UE passes through random access procedure, the uplink synchronous process of startup and target eNB,Wherein, uplink synchronous process can be according to whether there being non-competing random access resource information in switching command,Switching is divided into the switching of competition and non-competing switching, for non-competing switching, by non-competing moneySource is once only indicated to a UE and is used.

Step 106, target eNB is sent out up Timing Advance (TA, TimeAdvanced) informationDeliver to UE, and the ascending resource of indicating UE to need to target eNB feedback handoff completion message;

Step 105 to step 106 is handover execution stage, mainly carry out user random access procedure andThe forward process of user face data.

Step 107, target eNB receives handoff completion message, notice mobile management entity (MME,MobilityManagementEntity)/user entity (UPE, UserPlaneEntity) upgradesThe attaching information of UE.

In this step, in target eNB notice, MME/UPE upgrades after the attaching information of UE,MME/UPE can directly be sent to target eNB by new data, thereby completes switching flow.

This step, for to have switched the stage, is mainly that notice MME carries out the destination node conversion of user's face tunnel,And notification source eNB carries out resource release.

In the process that UE switches in execution, the time of expending while switching is called handover delay, i.e. UESend measure reporting information to target eNB notice MME/UPE upgrade the attaching information of UE required timeBetween; In handoff procedure, user face data sends time out and is called interruption time delay, and UE receives switchingThe time that UE can be required in the time of the normal transceiving data of target eNB is arrived in order, both weighs and switchesA very important index of algorithm quality, particularly for the high business of requirement of real-time, handover delayOr interrupt that time delay is long cannot meet quality of service (QoS, QualityofService) requirement, impactCommunication quality, experience thereby directly have influence on user in handoff procedure.

From above-mentioned, in existing LTE system, UE carries out the method for switching, alternative owing to not consideringThe real-time load information in community at target eNB place, makes UE may be switched to the real-time load in communityHigh target eNB, causes the satisfaction of switching rear user to decline; Further, select for source eNBGet eNB that all RSRP measured values that meet switch decision algorithm are corresponding as alternative target eNB'sSituation, sequentially chooses eNB that RSRP measured value is corresponding as alternative target eNB with respect to source eNBSituation, the interruption time delay that it causes is less, but this method has been brought necessarily to alternative target eNBData processing amount, need each alternative target feedback HANDOVERREQUESTACKNOWLEDGE message, particularly, for the alternative order of having indicated non-competing random access resourceMark eNB, may cause certain non-competing wasting of resources, this be because, due to non-competingResource once can only be indicated to a UE and be used, when alternative target eNB is by non-competing access-in resource informationWrite after HANDOVERREQUESTACKNOWLEDGE message, only receiving that UE is anti-The RRC message of feedback, or the HANDOVERCANCEL message sent of the source eNB of receiving, then orPerson, this alternative target eNB is feeding back HANDOVERREQUEST to source eNBAfter ACKNOWLEDGE message, starting protection timer, does not still receive at this timer expiryAny response message, could discharge current non-competing resource, the non-competing utilization of resources while making to switchRate is lower.

Summary of the invention

In view of this, main purpose of the present invention is to propose to determine in a kind of handoff procedure target BSMethod, the user satisfaction after the user experience in lifting subscriber handover process and switching complete.

Another object of the present invention is to propose to determine in a kind of handoff procedure the device of target BS, as far as possibleThe decline of user satisfaction after avoiding the decline of user experience in subscriber handover process and switching to complete.

For achieving the above object, the invention provides a kind of determine target BS in handoff procedure method,The method comprises:

According to the Reference Signal Received Power measured value threshold value setting in advance, the measurement receiving is reportedGrade classification is carried out in alternative target base station corresponding to Reference Signal Received Power measured value comprising in information;

Obtain the alternative target group of base stations that the highest grade, send handover request to this alternative target group of base stations and disappearBreath;

According to the switching priority computing formula setting in advance, calculate the handover request ack message pair receivingThe priority factors value of the alternative target base station of answering, by minimum priority factors value corresponding alternative target baseStand as target BS, the alternative target base station of returning to handover request ack message to other sends to switch and getsMessage, notice is cancelled this handoff procedure.

Described corresponding to the Reference Signal Received Power measured value comprising in the measurement reporting information receivingAlternative target base station is carried out grade classification and is specifically comprised:

Source base station based on receive measurement reporting information and the switch decision algorithm setting in advance, from referenceIn alternative target base station corresponding to signal received power measured value, be that subscriber equipment is selected alternative target base stationGroup;

Source base station carries out grade classification to the alternative target group of base stations of selecting.

The described alternative target base station using the minimum correspondence of priority factors value specifically comprises as target BS:

If the minimum corresponding alternative target base station number of priority factors value is one, this alternative target baseStand as the minimum corresponding alternative target base station of priority factors value;

If the minimum corresponding alternative target base station number of priority factors value is more than one, in conjunction with reference signalReceived power measured value information, selects the alternative target base of high correspondence of Reference Signal Received Power measured valueStand as target BS, or, from the plurality of alternative target base station, select at random an alternative target baseStand as target BS.

Described switching priority computing formula is as follows:

${\mathrm{PRI}}_m=\frac{N_{\mathrm{NotAdmitted}-\mathrm{RAB}}^m}{N_{\mathrm{total}-\mathrm{RAB}}}/\frac{\underset{k=0}{\overset{N_{\mathrm{NotAdmitted}-\mathrm{RAB}}^m-1}{\mathrm{\Σ}}}{\mathrm{QCI}}_k^{\mathrm{RAB}}}{\underset{i=0}{\overset{N_{\mathrm{total}-\mathrm{RAB}}-1}{\mathrm{\Σ}}}{\mathrm{QCI}}_i^{\mathrm{RAB}}}$ （1≤m≤N_total-Cell）

In formula,

PRI_mIt is the priority factors of m alternative target base station;

N_total-CellFor send the alternative target base station number of handover request ack message to source base station;

N_total-RABFor the current all business numbers of subscriber equipment;

N_{NotAdmitted-RAB}For not accepting the business number that subscriber equipment Zhe community is set up in alternative target base station,This value can obtain according to the E-RABsNotAdmittedList cell in handover request ack message;

For the QoS grade of business i.

In described handover request ack message, carry and switch relevant parameter, the parameter that described switching is relevantComprise: this alternative target base station can not accept subscriber equipment Zhe community set up business information list, shouldAlternative target base station is accepted the business information list of setting up subscriber equipment Zhe community and is needed source base stationPass through the switching command information of subscriber equipment.

Described measurement reporting information comprises: Reference Signal Received Power measured value information, the neighbour of this community are littleThe Reference Signal Received Power measured value information in district.

A device of determining target BS in handoff procedure, this device comprises: threshold value memory module,Grade classification module, the base station selected module of alternative target, priority factors value computing module and target baseThe determination module of standing, wherein,

Threshold value memory module, for storing the Reference Signal Received Power measured value grade classification of settingThreshold value;

Grade classification module, for according to Reference Signal Received Power measured value grade classification threshold value,To alternative target corresponding to Reference Signal Received Power measured value comprising in the measurement reporting information receivingGrade classification is carried out in base station;

The base station selected module of alternative target, for from alternative target group of base stations, obtains the highest grade standbySelect target BS group, send handover request message to this alternative target group of base stations;

Priority factors value computing module, for according to the switching priority computing formula setting in advance, countsCalculate the priority factors value of alternative target base station corresponding to handover request ack message receiving;

Target BS determination module, for using alternative target base station minimum corresponding priority factors value asTarget BS, the alternative target base station of returning to handover request ack message to other sends handover cancelling and disappearsBreath, notice is cancelled this handoff procedure.

Described target BS determination module comprises: minimum priority factors value acquiring unit, judging unit,Target BS selected cell and target BS determining unit, wherein,

Minimum priority factors value acquiring unit, for obtaining alternative order corresponding to minimum priority factors valueMark base station, described minimum priority factors value corresponds to TP top priority;

Judging unit, for the alternative target base station number that judges that minimum priority factors value acquiring unit is obtainedWhether be one, if so, export this alternative target base station to target BS determining unit, if not,Export each alternative target base station to target BS selected cell;

Target BS selected cell, for obtain reception each alternative target base station reference signal receive meritRate measured value information, selects the alternative target base station of high correspondence of Reference Signal Received Power measured value, or,From each alternative target base station, select at random an alternative target base station, export target BS to and determine singleUnit;

Target BS determining unit, for using receive alternative target base station as target BS.

As seen from the above technical solutions, determine target BS in a kind of handoff procedure provided by the inventionMethod and device, according to the Reference Signal Received Power measured value threshold value setting in advance, to what receiveMeasuring alternative target base station corresponding to Reference Signal Received Power measured value comprising in reporting information carries outGrade classification; Obtain the alternative target group of base stations that the highest grade, send and switch to this alternative target group of base stationsRequest message; According to the switching priority computing formula setting in advance, calculate the switching request response receivingThe priority factors value of alternative target base station corresponding to message, by the highest priority be that factor values is minimum correspondingAlternative target base station as target BS, to this alternative target group of base stations other returned handover request ringAnswer the alternative target base station of message to send notice, cancel this switching. Like this, by alternative target baseGrade classification is carried out at station, only sends handover request message to the highest grade alternative target group of base stations, effectivelyHaving reduced other alternative target eNB is to prepare to switch to carry out the required resource of data processing; By calculatingPriority factors value, can consider handover delay, cell load, QoS of survice requirement etc. to cuttingChange the impact of power into, improved handover success rate and also tried one's best and ensure to affect handoff procedure user's Experience DegreeUnaffected; Meanwhile, determining after target BS, return to the alternative of handover request ack message to otherTarget BS sends notice, cancels this handoff procedure, has effectively improved the resource utilization while switching.

Brief description of the drawings

Fig. 1 is that in existing LTE system, UE carries out the schematic flow sheet switching.

Fig. 2 is the method flow schematic diagram of determining target BS in embodiment of the present invention handoff procedure.

Fig. 3 is the method idiographic flow schematic diagram of determining target BS in embodiment of the present invention handoff procedure.

Fig. 4 is the apparatus structure schematic diagram of determining target BS in embodiment of the present invention handoff procedure.

Detailed description of the invention

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing and concreteThe present invention is described in further detail for embodiment.

In the embodiment of the present invention, in existing handoff procedure, on the basis of definite target BS method, carry outImprove, do not changing under the prerequisite of agreement, utilize existing measurement reporting information, handover request ack messageIn the content that comprises, consider handover delay, cell load, QoS of survice requirement etc. to switching toThe impact of power, after avoiding the decline of user's user experience in handoff procedure and switching to complete as far as possibleThe decline of user satisfaction.

Fig. 2 is the method flow schematic diagram of determining target BS in embodiment of the present invention handoff procedure. Referring toFig. 2, this flow process comprises:

Step 201, according to the RSRP measured value threshold value setting in advance, reports the measurement receivingAlternative target eNB corresponding to RSRP measured value comprising in information carries out grade classification;

Measuring reporting information mainly comprises: the RSRP measured value information of this community, the RSRP of adjacent cellMeasured value information.

Alternative target eNB corresponding to RSRP measured value comprising in the measurement reporting information receiving enteredRow grade classification specifically comprises:

A11, source eNB based on receive measurement reporting information and the switch decision algorithm setting in advance,For UE selects alternative target eNB;

In this step, source eNB, from the RSRP measured value information receiving, chooses all switchings that meetENB corresponding to the RSRP measured value of decision algorithm is as alternative target eNB.

A12, source eNB carry out grade classification to the alternative target eNB selecting.

In this step, source eNB is receiving measurement reporting information and is choosing after alternative target eNB,According to the RSRP measured value threshold value setting in advance, survey measuring the RSRP comprising in reporting informationThe alternative target eNB that value is corresponding carries out grade classification, is about in same classification RSRP measured valueAlternative target eNB corresponding to RSRP measured value in threshold range is divided into same grade alternative targetENB group. For instance, if a certain RSRP comprising in the measurement reporting information that UE reports measuresValue is greater than a RSRP measured value threshold value, by alternative target eNB corresponding this RSRP measured valueBe grouped into the first classification alternative target eNB group, measure if another RSRP measured value is less than a RSRPValue threshold value and be greater than the 2nd RSRP measured value threshold value, by alternative target corresponding this RSRP measured valueENB is grouped into the second classification alternative target eNB group, by that analogy.

Step 202, obtains the alternative target eNB group that the highest grade, sends out to this alternative target eNB groupSend handover request message;

In this step, the each RSRP measured value correspondence comprising in the measurement reporting information that UE is reportedAlternative target eNB carry out, after grade classification, obtaining the alternative target eNB group that the highest grade, to thisAlternative target eNB group sends handover request message, like this, and without to all switch decision algorithms that meetAlternative target eNB send handover request message, thereby effectively reduce alternative target eNB for preparingSwitch and carry out the required resource of data processing, also reduced this alternative target eNB and returned and cut to source eNBChange the required Internet resources of request response, saved Internet resources, alleviated offered load.

In HANDOVERREQUEST message, carry the contextual information of UE, the context of UEInformation spinner will comprise: the QoS information of the current all business of UE, security capabilities information and the AS of UESecurity information etc.

Step 203, according to the switching priority computing formula setting in advance, calculates the handover request receivingThe priority factors value of the alternative target eNB that response message is corresponding, by minimum priority factors value correspondingAlternative target eNB as target eNB, return to HANDOVERREQUEST to otherThe alternative target eNB of ACKNOWLEDGE message sends the HANDOVER that cancels this switchingCANCEL.

In this step, alternative target eNB receives handover request message, determines whether to receive UE, ifCan meet any one UE and wish the business need of setting up in target eNB, receive UE, and beUE distributes cell-radio network temporary indentification (C-RNTI) and switches relevant parameter, inserts and cutsChange in order, switching command and alternative target base station be can be to UE use service and that cannot receiveFamily business information list is carried in handover request ack message, sends to source eNB. If cannot expireAny one UE of foot wishes the business need of setting up in target eNB, returns to switch prepare to source eNBFailed message.

Switching relevant parameter comprises: the physical I D of Radio Resource common configuration information, target eNB,The information such as system up-downgoing carrier bandwidths information and random access resource.

Switch priority computing formula as follows:

${\mathrm{PRI}}_m=\frac{N_{\mathrm{NotAdmitted}-\mathrm{RAB}}^m}{N_{\mathrm{total}-\mathrm{RAB}}}/\frac{\underset{k=0}{\overset{N_{\mathrm{NotAdmitted}-\mathrm{RAB}}^m-1}{\mathrm{\Σ}}}{\mathrm{QCI}}_k^{\mathrm{RAB}}}{\underset{i=0}{\overset{N_{\mathrm{total}-\mathrm{RAB}}-1}{\mathrm{\Σ}}}{\mathrm{QCI}}_i^{\mathrm{RAB}}}$ （1≤m≤N_total-Cell）

In formula,

PRI_mIt is the priority factors of m alternative target eNB;

N_total-CellFor send the alternative target eNB number of handover request ack message to source eNB;

N_total-RABFor the current all business numbers of UE;

N_{NotAdmitted-RAB}For alternative target eNB can not accept the business number that UEZhe community is set up, this valueCan obtain according to the E-RABsNotAdmittedList cell in handover request ack message;

For the Qos grade of business i.

As can be seen from the above equation, the highest grade is priority factors value minimum, andRatio moreLittle, illustrate this alternative target cells m can accept UEZhe community set up business number more, relative, the load state of this alternative target eNB is better; AndRatio is less, explanationThis alternative target eNB can not be for switching the higher grade of business QCI of setting up user Zhe community, causesThe satisfaction of telex network process declines larger, and meanwhile, this value is less, also can secondary indication this is alternativeThe load state of target eNB is poorer.

Like this, by calculating priority level factor values, can consider handover delay, cell load, industryThe impact on handover success rate such as business qos requirement, if the priority factors value calculating is less,The integrated status that shows this alternative target eNB is better, selects the alternative of the minimum correspondence of priority factors valueTarget eNB is as target eNB, thereby can improve the success rate of switching.

Meanwhile, by return to HANDOVERREQUESTACKNOWLEDGE message to otherAlternative target eNB send HANDOVERCANCEL message, notice is cancelled and being switched, like this,Other alternative target eNB that return to HANDOVERREQUESTACKNOWLEDGE message withoutNeed be the reserved switchable resource of UE again, and without upgrading UE's at target eNB notice MME/UPEAfter attaching information, then return to HANDOVERREQUEST by source eNB to otherThe alternative target eNB of ACKNOWLEDGE message sends handover cancelling (HANDOVERCANCEL) message, also without protection timer expiry after, notice cancel switch, thereby can andTime discharge switchable resource, also improved the level of resources utilization of these alternative target eNB.

Fig. 3 is the method idiographic flow schematic diagram of determining target BS in embodiment of the present invention handoff procedure.Referring to Fig. 3, this flow process comprises:

Step 301, the RSRP measured value information comprising in the measurement reporting information reporting according to UE,Obtain the alternative target eNB that meets the switch decision algorithm setting in advance;

In this step, switch decision algorithm can be that the maximum RSRP in RSRP measured value threshold value surveysValue threshold value, i.e. a RSRP measured value threshold value.

Step 302, determines that alternative target eNB number is more than one, measures according to the RSRP setting in advanceValue threshold value, carries out grade classification to alternative target eNB;

In this step, if alternative target eNB number is one, the contextual information of UE is carried atIn HANDOVERREQUEST message, be sent to this alternative target eNB, follow-up according to existing streamCheng Jinhang processes, and does not repeat them here. If alternative target eNB number is more than one, according to establishing in advanceThe RSRP measured value threshold value of putting is corresponding to measuring the RSRP measured value comprising in reporting informationAlternative target eNB carries out grade classification.

RSRP measured value threshold value can arrange according to actual needs.

Step 303 is chosen the highest classification alternative target of classification from each classification alternative target eNB groupENB group, all eNB in the alternative target eNB group of this grade send HANDOVERREQUEST message;

In this step, by the RSRP measured value threshold value setting in advance, to alternative target eNBDivide into groups, all eNB in the highest grade alternative target eNB group send HANDOVERREQUEST message, carries out data thereby reduced other grade alternative target eNB group for carrying out to switchProcess required resource.

Step 304, according to the HANDOVERREQUESTACKNOWLEDGE message receivingIn the cell E-RABsNotAdmittedList that carries, the priority of calculating each alternative target eNB because ofSon;

In this step, be HANDOVERPREPARATION if alternative target eNB returnsFAILURE message, shows that this alternative target eNB does not receive this UE, according to existing procedure placeReason.

The priority factors value of alternative target eNB is less, shows that higher grade, this alternative target eNBComprehensive switch instances better, more adapt to the target eNB as UE.

Step 305, obtains the minimum corresponding alternative target eNB of priority factors value as target eNB;

In this step, the priority factors value of obtaining is sorted from small to large according to value, thereby obtainGet the minimum corresponding alternative target eNB of priority factors value.

Obtaining the minimum corresponding alternative target eNB of priority factors value specifically comprises:

If the minimum corresponding alternative target eNB number of priority factors value is one, this alternative targetENB is the minimum corresponding alternative target eNB of priority factors value;

If the minimum corresponding alternative target eNB number of priority factors value is more than one, can enter oneStep is in conjunction with RSRP measured value information, selects the alternative target eNB conduct of high correspondence of RSRP measured valueTarget eNB, or, from the plurality of alternative target eNB, select at random an alternative target eNB to doFor target eNB.

Step 306, returns to HANDOVERREQUESTACKNOWLEDGE message to otherAlternative target eNB return to HANDOVERCANCEL, notice cancel switch.

So far the flow process of, determining target BS in handoff procedure finishes.

In follow-up, the HANDOVERREQUEST that source eNB sends target eNBThe switching command carrying in ACKNOWLEDGE message passes through UE, and UE is according to the switching life receivingOrder, the uplink synchronous process of startup and target eNB, until target eNB receives handoff completion message,Notice MME/UPE upgrades the flow process of attaching information of UE, identical with existing procedure, specifically can be referring toCorrelation technique document, does not repeat them here.

The embodiment of the present invention that it should be noted that is in the handoff procedure based on X2 interface, to determine target baseThe method of standing, the method goes for minizone in eNB equally to be switched, and based on S1 interfaceBetween eNB, switch.

Fig. 4 is the apparatus structure schematic diagram of determining target BS in embodiment of the present invention handoff procedure. Referring toFig. 4, this device comprises: threshold value memory module, grade classification module, alternative target are base station selectedModule, priority factors value computing module and target BS determination module, wherein,

Threshold value memory module, for storing the RSRP measured value threshold value of setting;

In the embodiment of the present invention, can be according to actual needs, to the RSRP measured value threshold value of storageUpgrade.

Grade module, for according to RSRP measured value threshold value, in the measurement reporting information receivingAlternative target eNB corresponding to RSRP measured value comprising carries out grade classification;

The base station selected module of alternative target, for from alternative target eNB group, obtains the highest gradeAlternative target eNB group, sends handover request message to this alternative target eNB group;

Priority factors value computing module, for according to the switching priority computing formula setting in advance, countsCalculate the priority factors value of alternative target eNB corresponding to handover request ack message receiving;

In the embodiment of the present invention, switch priority computing formula as follows:

${\mathrm{PRI}}_m=\frac{N_{\mathrm{NotAdmitted}-\mathrm{RAB}}^m}{N_{\mathrm{total}-\mathrm{RAB}}}/\frac{\underset{k=0}{\overset{N_{\mathrm{NotAdmitted}-\mathrm{RAB}}^m-1}{\mathrm{\Σ}}}{\mathrm{QCI}}_k^{\mathrm{RAB}}}{\underset{i=0}{\overset{N_{\mathrm{total}-\mathrm{RAB}}-1}{\mathrm{\Σ}}}{\mathrm{QCI}}_i^{\mathrm{RAB}}}$ （1≤m≤N_total-Cell）

In formula,

PRI_mIt is the priority factors of m alternative target eNB;

N_total-CellFor send the alternative target eNB number of handover request ack message to source eNB;

N_total-RABFor the current all business numbers of UE;

N_{NotAdmitted-RAB}For alternative target eNB can not accept the business number that UEZhe community is set up, this valueCan obtain according to the E-RABsNotAdmittedList cell in handover request ack message;

For the QoS grade of business i.

Target BS determination module, for by the highest priority be alternative target corresponding to factor valuesENB is as target eNB, and the alternative target eNB that returns to handover request ack message to other sends logicalKnow and cancel the handover cancelling message of switching.

Wherein, target BS determination module comprises: minimum priority factors value acquiring unit, judging unit,Target BS selected cell and target BS determining unit (not shown), wherein,

Minimum priority factors value acquiring unit, for obtaining the alternative target eNB that priority is the highest,Alternative target eNB corresponding to minimum priority factors value;

Judging unit, for the alternative target eNB that judges that minimum priority factors value acquiring unit is obtainedWhether number is one, if so, exports this alternative target eNB to target BS determining unit, asFruit is no, exports each alternative target eNB to target BS selected cell;

Target BS selected cell, for obtaining the RSRP measured value of each alternative target eNB of receptionInformation, selects the alternative target eNB of high correspondence of RSRP measured value, or, from each alternative target eNBIn, select at random an alternative target eNB, export target BS determining unit to;

Target BS determining unit, for using receive alternative target eNB as target eNB.

The foregoing is only preferred embodiment of the present invention, be not intended to limit protection model of the present inventionEnclose. Within the spirit and principles in the present invention all, any amendment of doing, be equal to and replace and improvement etc.,Within all should being included in protection scope of the present invention.

Claims (7)

1. a method of determining target BS in handoff procedure, is characterized in that, the method comprises:

According to the Reference Signal Received Power measured value threshold value setting in advance, the measurement receiving is reportedGrade classification is carried out in alternative target base station corresponding to Reference Signal Received Power measured value comprising in information;

Obtain the alternative target group of base stations that the highest grade, send handover request to this alternative target group of base stations and disappearBreath;

According to the switching priority computing formula setting in advance, calculate the handover request ack message pair receivingThe priority factors value of the alternative target base station of answering, by minimum priority factors value corresponding alternative target baseStand as target BS, the alternative target base station of returning to handover request ack message to other sends to switch and getsMessage, notice is cancelled this handoff procedure;

Described switching priority computing formula is as follows:

${\mathrm{PRI}}_m=\frac{N_{NotAdmitted-RAB}^m}{N_{total-RAB}}/\frac{\underset{k=0}{\overset{N_{NotAdmitted-RAB}^m-1}{\Σ}}{\mathrm{QCI}}_k^{RAB}}{\underset{i=0}{\overset{N_{total-RAB}-1}{\Σ}}{\mathrm{QCI}}_i^{RAB}},(1\≤m\≤N_{total-Cell})$

In formula,

PRI_mIt is the priority factors of m alternative target base station;

N_total-CellFor send the alternative target base station number of handover request ack message to source base station;

N_total-RABFor the current all business numbers of subscriber equipment;

N_{NotAdmitted-RAB}For not accepting the business number that subscriber equipment Zhe community is set up in alternative target base station,N_{NotAdmitted-RAB}Can be according to the E-RABsNotAdmittedList cell in handover request ack messageObtain;

For the QoS grade of business i.

2. the method for claim 1, is characterized in that, described to notifying in the measurement receivingGrade classification tool is carried out in alternative target base station corresponding to Reference Signal Received Power measured value comprising in breathBody comprises:

Source base station based on receive measurement reporting information and the switch decision algorithm setting in advance, from referenceIn alternative target base station corresponding to signal received power measured value, be that subscriber equipment is selected alternative target base stationGroup;

Source base station carries out grade classification to the alternative target group of base stations of selecting.

3. the method for claim 1, is characterized in that, described by priority factors value minimumCorresponding alternative target base station specifically comprises as target BS:

If the minimum corresponding alternative target base station number of priority factors value is one, this alternative target baseStand as the minimum corresponding alternative target base station of priority factors value;

If the minimum corresponding alternative target base station number of priority factors value is more than one, in conjunction with reference signalReceived power measured value information, selects the alternative target base of high correspondence of Reference Signal Received Power measured valueStand as target BS, or, from multiple alternative target base station, select at random an alternative target base stationAs target BS.

4. the method as described in claims 1 to 3 any one, is characterized in that, described handover requestIn response message, carry and switch relevant parameter, the parameter that described switching is relevant comprises: this alternative targetBusiness information list, this alternative target base station that base station can not be accepted to set up subscriber equipment Zhe community are acceptedThe business information list that subscriber equipment Zhe community is set up and need source base station to pass through subscriber equipmentSwitching command information.

5. method as claimed in claim 4, is characterized in that, described measurement reporting information comprises:The Reference Signal Received Power measured value information of this community, the Reference Signal Received Power measured value of adjacent cellInformation.

6. a device of determining target BS in handoff procedure, is characterized in that, this device comprises:Threshold value memory module, grade classification module, the base station selected module of alternative target, priority factors valueComputing module and target BS determination module, wherein,

Threshold value memory module, for storing the Reference Signal Received Power measured value grade classification of settingThreshold value;

Grade classification module, for according to Reference Signal Received Power measured value grade classification threshold value,To alternative target corresponding to Reference Signal Received Power measured value comprising in the measurement reporting information receivingGrade classification is carried out in base station;

The base station selected module of alternative target, for from alternative target group of base stations, obtains the highest grade standbySelect target BS group, send handover request message to this alternative target group of base stations;

Priority factors value computing module, for according to the switching priority computing formula setting in advance, countsCalculate the priority factors value of alternative target base station corresponding to handover request ack message receiving;

Described switching priority computing formula is as follows:

${\mathrm{PRI}}_m=\frac{N_{NotAdmitted-RAB}^m}{N_{total-RAB}}/\frac{\underset{k=0}{\overset{N_{NotAdmitted-RAB}^m-1}{\Σ}}{\mathrm{QCI}}_k^{RAB}}{\underset{i=0}{\overset{N_{total-RAB}-1}{\Σ}}{\mathrm{QCI}}_i^{RAB}},(1\≤m\≤N_{total-Cell})$

In formula,

PRI_mIt is the priority factors of m alternative target base station;

N_total-CellFor send the alternative target base station number of handover request ack message to source base station;

N_total-RABFor the current all business numbers of subscriber equipment;

N_{NotAdmitted-RAB}For not accepting the business number that subscriber equipment Zhe community is set up in alternative target base station,N_{NotAdmitted-RAB}Can be according to the E-RABsNotAdmittedList cell in handover request ack messageObtain;

For the QoS grade of business i; Target BS determination module, for by priority factors valueThe standby of handover request ack message, as target BS, returned to other in minimum corresponding alternative target base stationSelect target BS to send handover cancelling message, notice is cancelled this handoff procedure.

7. device as claimed in claim 6, is characterized in that, described target BS determination module bagDraw together: minimum priority factors value acquiring unit, judging unit, target BS selected cell and target baseThe determining unit of standing, wherein,

Minimum priority factors value acquiring unit, for obtaining alternative order corresponding to minimum priority factors valueMark base station, described minimum priority factors value corresponds to TP top priority;

Judging unit, for the alternative target base station number that judges that minimum priority factors value acquiring unit is obtainedWhether be one, if so, export this alternative target base station to target BS determining unit, if not,Export each alternative target base station to target BS selected cell;

Target BS selected cell, for obtain reception each alternative target base station reference signal receive meritRate measured value information, selects the alternative target base station of high correspondence of Reference Signal Received Power measured value, or,From each alternative target base station, select at random an alternative target base station, export target BS to and determine singleUnit;

Target BS determining unit, for using receive alternative target base station as target BS.