Embodiment
In order to make those skilled in the art person understand the scheme of the embodiment of the invention better, the embodiment of the invention is done further to specify below in conjunction with accompanying drawing and execution mode.
In realizing process of the present invention; The inventor find handoff failure normally UE lose with the relevant signaling between the network side or wrong causing, and cause said relevant signaling to be lost or wrong reason mostly is because parameter is provided with improper or network (comprising website or antenna) planning is unreasonable or user's fast moving etc.For this reason, the embodiment of the invention is to the handoff failure phenomenon that occurs in LTE (Long Term Evolution, the Long Term Evolution) network; The incident and the metrical information that report according to UE; Confirm to cause the true cause of failure, and then handoff parameter is adjusted automatically, reduce the handoff failure probability; Reduce cutting off rate, improve user experience.
Fig. 1 shows a space interface signaling interaction flow in the handoff procedure, may further comprise the steps:
1.UE send the RRC measurement report to the cell-of-origin;
2. the cell-of-origin is sent to switch to one or more sub-districts (comprising Target cell and preparation cells) and is prepared message, after these sub-districts are the UE distributing radio resource, return to switch and prepares acknowledge message;
3. which preparation cells the cell-of-origin determines as the Target cell that switches according to correlation criterion, sends RRC reconfiguration message, i.e. switching command to UE then;
4.UE MAC (Media Access Control, medium access control) layer logic entity successfully receive message after, send HARQ (Hybrid Auto Repeat Request mixes automatic repeat requests) acknowledge message;
5.UE carry out down-going synchronous with Target cell;
Synchronously after UE send uplink random access lead (special-purpose or at random);
7. after Target cell is received the uplink random access lead, send descending accidental access response message;
8.UE after receiving the response message of target side, send up RRC and reshuffle completion message;
9. the MAC layer logic entity of Target cell successfully received and reshuffled completion message, sends the HARQ acknowledge message to UE, simultaneously to MME transmit path transforming message;
10. if there is downlink data to need to send, then Target cell uses PDCCH (Packet Dedicated Control Channel, grouping DCCH) to send control information to UE, and indication UE prepares downlink data receiving;
11. the RLC of Target cell (Radio Link Control, Radio Link control) layer logic entity sends downstream state information, Target cell sends resource release message to the cell-of-origin.
When UE inserts in target side at random, use the situation of dedicated preamble, after UE receives A3 message, just think handover success for UE; Use the situation of lead code at random for UE, have only as UE and receive A6 message, promptly during first descending PDCCH control signaling, just think handover success.
Visible by above-mentioned flow process, the rrc layer signaling message of interface transmission aloft mainly contains in the handoff procedure: measurement report, switching command and switching are confirmed.Wherein, measurement report is the upstream message that UE sends to network side, and switching command is the downstream message that the cell-of-origin of switching sends to UE, switches and confirms it is the upstream message that UE sends to the Target cell of switching.Signaling message is lost the following several kinds of situation that mainly contain:
(1) measurement report is lost.When measurement report can't successfully send to network side and reach maximum retransmission, UE can initiate RRC and rebuild.Also might be before reaching maximum times, user's quality of wireless channel deteriorates into to a certain degree, and Radio Link Failure takes place, and UE initiates RRC and rebuilds.
(2) switching command is lost.Switching command is lost probably causes that all Radio Link Failure can take place usually, UE initiates the RRC reconstruction afterwards because radio link conditions worsens.
(3) switch acknowledgment message is lost.At this moment UE inserts success in target side at random, and Target cell has become Serving cell.When switch acknowledgment message can't successfully send to network side and reach maximum retransmission, UE can initiate RRC and rebuild.
It is thus clear that the whichever signaling message is lost or mistake, all can cause handoff failure or Radio Link Failure.
The switching optimization method of the embodiment of the invention; Based on the RRC process of reconstruction behind switching and the handoff failure; Obtain the incident and the metrical information that write down in the UE handoff procedure; Confirm because the handoff parameter of handoff failure that handoff parameter causes and needs adjustment according to said incident and metrical information, the handoff parameter of needs adjustment is sent to and switches relevant sub-district, thereby realize self-optimizing the UE switching.
In order to realize the self-optimizing of LTE network; Can begin from sending the RRC measurement report by UE to the cell-of-origin; Finish up to the RRC process of reconstruction; The a series of incidents and the metrical information that take place during the record, behind the handoff failure, UE sends to the SON functional entity with the incident and the metrical information of record; Confirm according to these incidents and metrical information because handoff parameter is provided with the handoff parameter of improper handoff failure that causes and needs adjustment by the SON functional entity, the handoff parameter of needs adjustment is sent to and switches relevant sub-district.Wherein, said SON functional entity is a logic entity, and it can be arranged in the Operational Management System of network, also can part of functions be arranged in said Operational Management System, and another part function is arranged in the base station.Can confirm that according to actual needs the embodiment of the invention does not limit this during concrete the application.
As shown in Figure 2, be the flow chart of embodiment of the invention UE switching optimization method, mainly may further comprise the steps:
Step 201 is obtained the incident and the metrical information that write down in the UE handoff procedure.
In embodiments of the present invention, can be begun from sending measurement report by UE, till the RRC process of reconstruction finished, no matter be handover success or failure, a series of incidents, object and the metrical information that take place during the record mainly comprised:
(1) message (comprising measurement report, switching command, switching affirmation etc.) is sent or the reception incident, the Radio Link Failure incident, and RRC rebuilds incident, at the access events at random of target side, and the time interval between each incident;
(2) frequency of the sub-district relevant with above-mentioned each incident and physical layer identifications (PCI) comprise subdistrict frequency point and PCI resident when Serving cell frequency and PCI, Target cell frequency and PCI, reconstruction finish;
When (3) incident takes place; The signal measurement amount of the sub-district that relates to: reference symbol received power (RSRP and/or the reference symbol quality of reception (RSRQ); The RSRP and/or the RSRQ of Serving cell when comprising RSRP and/or RSRQ, the Radio Link Failure of Serving cell and Target cell in the measurement report, RRC rebuild successfully or the RSRP and/or the RSRQ of the resident sub-district, back of failing;
Also can further comprise:
(4) translational speed of UE oneself estimation;
(5) if UE possesses positioning function, the geographical position coordinates of UE when also wanting recording events to take place.
UE can be an effective time of every recording setting (this time can also can be provided with by UE oneself, such as being set to half an hour or 1 hour or the like by network settings).If RRC rebuilds successfully, UE still is in connection status, sends this record in the network SON functional entity through up-to-date serving BS.If the RRC reconstruction failure, then UE loses connection, gets into idle condition, and UE might initiate again to connect and set up.So when UE gets into connection status next time, as long as also in effective time, UE just will write down through serving BS and send the SON functional entity in the network to.If effective time is overtime, UE does not still have to send this record in the network SON functional entity, so just deletes overtime record.
Step 202, definite according to said incident and metrical information because handoff parameter is provided with the handoff parameter of improper handoff failure that causes and needs adjustment.
The SON functional entity is according to a large amount of UE handoff failure records of from network, collecting; Be incident and the metrical information that UE writes down in handoff procedure; The handoff parameter of determining owing to the improper handoff failure that causes of handoff parameter and needing to adjust, concrete definite process will be described in detail later.
If the SON functional entity can also obtain the translational speed of UE oneself estimation; When the rate travel that can be set in UE is no more than a predetermined value; Need to confirm the handoff parameter of adjustment according to the method for the embodiment of the invention, otherwise can adopt additive method to confirm.
Step 203 sends to the handoff parameter of needs adjustment and switch relevant sub-district.
The SON functional entity sends instruction through the base station to respective cell, and inappropriate parameter is revised in indication.
Below further combine switching and the RRC process of reconstruction of UE, be described in detail under the different failed handoff scenario SON functional entity and how confirm the improper handoff failure that causes of handoff parameter.
Need to prove that the measurement report of the following stated does not comprise being used for the report that SON ANR (neighborhood automatically) measures, and the report that is used to measure the control of GAP (measuring at interval) switch.
1. send measurement report failure-RRC and rebuild request-reconstruction failure, get into the IDLE attitude, reside in another sub-district
This scene is following: UE sends measurement report; But do not receive the affirmation information that network returns, up to reaching maximum number of times of transmission, RLC (Radio Link Control; Radio Link control) layer reporting errors perhaps detects according to physical layer Radio Link Failure takes place; UE initiates the RRC process of reconstruction then, but reconstruction failure, the RRC connection of UE is lost, and gets into idle condition, and the resident sub-district that is different from the source Serving cell to another supposes that this sub-district is sub-district A.
The SON functional entity is according to the incident and the metrical information that write down in the UE handoff procedure that obtains, checks the sub-district A that in measurement report, whether comprises after the reconstruction.
If comprise the sub-district A after the reconstruction in the measurement report; Then compare and measure in the report and these two constantly RSRP and/or the RSRQ values of sub-district A behind the reconstruction failure; If the measured value that is somebody's turn to do when previous is apparently higher than the respective measurement values in a back moment, for example surpass 3dB, and the RSRP of Serving cell and/or the respective measurement values that RSRQ also is starkly lower than sub-district A in the measurement report in the measurement report; Can confirm that then switching condition is provided with too strictly; Neighboring area signal is very strong UE is reporting measurement reports, and at this moment the Serving cell radio link quality is relatively poor, and message can not correctly be received by the base station.This means that change action is too late, missed preferable switching instant.To this situation, need to reduce switching threshold, and/or reduce lagged value, and/or reduce the reporting measuring result triggered time, change action can be shifted to an earlier date.
2. send measurement report-Radio Link Failure (reason is not receive switching command)-RRC reconstruction and ask-rebuild successfully, transfer to another sub-district
This scene is following: UE successfully sends measurement report, and Radio Link Failure takes place soon, and before Radio Link Failure takes place, does not receive switching command; UE initiates the RRC reconstruction then; Rebuild successfully, UE transfers to another sub-district, supposes that this sub-district is sub-district B.
RRC rebuilds successfully, explains that final resident sub-district B appears in the measurement report message, satisfies and switches requirement, and be chosen to be the switching preparation cells by the base station.In this case; Can when relatively sending measurement report and Radio Link Failure take place the time; The RSRP and/or the RSRQ value of these two moment Serving cells, and newly sub-district (the sub-district B after promptly rebuilding) reaches reconstruction RSRP and/or RSRQ value afterwards in measurement report.If former Serving cell is in two measured value difference little (such as less than first threshold) in above-mentioned two moment; Sub-district B is in two measured value difference in above-mentioned two moment also little (such as less than second threshold value); And sub-district B at the mean value of the measured value in above-mentioned two moment obviously greater than the mean value (such as greater than three threshold value) of former Serving cell at the measured value in above-mentioned two moment; Then possibly be that handoff parameter is improper; It is slow to cause switching, and when sending measurement report, the signal quality of Serving cell has been difficult to guarantee the correct reception of air-interface information.To this situation, need to reduce switching threshold, and/or reduce lagged value, and/or reduce the reporting measuring result triggered time, change action can be shifted to an earlier date.
First threshold recited above, second threshold value and the 3rd threshold value can be set according to actual application environment.
3. send measurement report-receive cut change life and make – target side at random access failure-RRC rebuild and ask-rebuild successfully, return the preceding sub-district of switching
This scene is following: UE sends measurement report, and receives switching command, but at the target side access failure, UE initiates the RRC reconstruction subsequently, rebuilds successfully, and UE turns back to the cell-of-origin before switching.
This situation means that for the sub-district before switching switched too early, the signal quality of Target cell is not enough to guarantee the access of UE.Therefore the comparison object sub-district is in measurement report, at random during access failure and when reconstruction, the RSRP in these three moment and/or RSRQ value.
If the respective measurement values in three moment is more or less the same (such as all less than the 4th threshold value), explain that the signal of Target cell is more stable, access failure means that this signal quality does not reach the degree of service UE at random.For this situation, can be through changing handoff parameter, as increasing switching threshold, and/or increase lagged value, improve the requirement that UE switches, so that Target cell intensity just triggers switching when reaching higher level.
If first measured value constantly is apparently higher than latter two measured value (such as all being higher than the 5th threshold value) constantly; Then can confirm it is reason owing to the actual propagation environment; Make Target cell described position signalling of UE when UE sends measurement report more intense, but other position still a little less than.For this situation, can increase the reporting measuring result triggered time, through delaying measurement and report, filter the violent shake of neighbor cell signal to a certain extent at boundary.
The 4th threshold value recited above, the 5th threshold value can be set according to actual application environment.
4. send measurement report-receive cut change life and make – insert success-transmissions switch acknowledgment message failure-RRC at random in target side and rebuild and ask-rebuild successfully, return the preceding sub-district of switching
This scene is following: UE sends measurement report, and receives switching command, inserts success at random at Target cell then; But send up switching message failure, reach maximum number of times of transmission after, UE initiates RRC and rebuilds; Rebuild successfully, UE turns back to the cell-of-origin before switching.
Scene under this scene and above-mentioned the 3rd kind of situation is similar; Under this scene; The SON functional entity is according to the incident and the metrical information that write down in the UE handoff procedure that obtains; Confirm that handoff failure that causes owing to handoff parameter and process and the process under above-mentioned the 3rd kind of situation of the handoff parameter that needs adjustment are similar, be not described in detail at this.
Need to prove that above-mentioned switching threshold, lagged value and reporting measuring result triggered time are identical with implication of the prior art.Wherein, said switching threshold is meant that when judging handover triggering condition, neighbor cell signal intensity surpasses the difference of current service cell.Said lagged value, be meant that difference that neighbor cell signal intensity surpasses current service cell reaches threshold value after, also to surpass a difference again and just think and satisfy trigger condition, this extra difference is lagged value, it is mainly used in and prevents that table tennis from switching.The said reporting measuring result triggered time is meant that measurement result satisfies the report condition needs after lasting such a period of time, and report is just really sent to network in the terminal, mainly is the situation that is used for preventing the measurement result shake.
It is thus clear that; The incident that embodiment of the invention switching optimization method writes down in handoff procedure according to UE, with working frequency points and the physical layer identifications and the measured value of said incident related cell; The handoff parameter of confirming owing to the improper handoff failure that causes of handoff parameter and needing to adjust; Can improve the accuracy rate of confirming the handoff failure reason, and the handoff parameter that will adjust sends to and switch relevant sub-district, make said sub-district carry out relevant parameters and optimize and revise; Thereby can reduce the handoff failure probability of happening, improve user's experience.
One of ordinary skill in the art will appreciate that all or part of step that realizes in the foregoing description method is to instruct relevant hardware to accomplish through program; Described program can be stored in the computer read/write memory medium; Described storage medium, as: ROM/RAM, magnetic disc, CD etc.
The embodiment of the invention also provides a kind of handover optimization equipment, and is as shown in Figure 3, is the structural representation of this handover optimization equipment.
This handover optimization equipment comprises: unit 302 and transmitting element 303 are confirmed in acquiring unit 301, parameter adjustment.Wherein:
Acquiring unit 301, be used for obtaining incident that the UE handoff procedure writes down, with working frequency points and the physical layer identifications and the measured value of said incident related cell;
Unit 302 is confirmed in parameter adjustment, is used for according to said incident, with the working frequency points of said incident related cell and physical layer identifications and measured value confirms because the handoff parameter of handoff failure that handoff parameter causes and needs adjustment;
Transmitting element 303 is used for handoff parameter with needs adjustment and sends to and switch relevant sub-district.
To by the agency of in the description of switching optimization method of the present invention, said incident comprises following any one or more incidents in front: the switching command that measurement report sends success or failure, Radio Link Failure, whether UE receives automatic network before Radio Link Failure takes place, send switch acknowledgment message success or failure, insert success or failure, UE at random and send radio resource control connection reestablishment request, UE and send that radio resource control connection reestablishment is accomplished message or UE receives the radio resource control connection reestablishment refuse information; Said measured value comprises: when said incident takes place; With the reference symbol received power of said incident related cell and/or with the reference symbol quality of reception of said incident related cell, also can further comprise: the translational speed of UE estimation, the geographical position coordinates of UE.Thereby can make parameter adjustment confirm that unit 302 further combines the translational speed of UE need to determine whether the adjustment handoff parameter.
In embodiments of the present invention, said parameter adjustment confirms that a kind of preferred structure of unit 302 is as shown in Figure 3, comprising: the handoff failure state is confirmed subelement 321, measured value relatively subelement 322 and handoff parameter analysis subelement 323.Wherein:
The handoff failure state is confirmed subelement 321, be used for according to said incident, with the working frequency points of said incident related cell and the scene that physical layer identifications is confirmed the UE handoff failure;
Measured value is subelement 322 relatively, when being used for comparison different event taking place under said scene, and the measured value relevant with said incident;
Handoff parameter is analyzed subelement 323, is used for need confirming the handoff parameter of adjustment according to the scene of UE handoff failure and the said measured value comparative result of subelement 322 relatively.Particularly, can have following several kinds of situation need adjust handoff parameter:
(1) if confirms that according to said incident and metrical information UE sends measurement report failure back reconstruction failure and resident to a sub-district that is included in the measurement report; And the measured value of this sub-district is higher than the respective measurement values of this sub-district behind the reconstruction failure in the measurement report; And the respective measurement values that is higher than Serving cell in the said measurement report, then confirming needs the handoff parameter of adjustment to comprise following one or more arbitrarily: reduce switching threshold, reduce lagged value, reduce the reporting measuring result triggered time;
(2) if confirm that according to said incident and metrical information UE sends Radio Link Failure behind the measurement report; Rebuild successfully also resident afterwards to a switching preparation cells that is included in the measurement report; And differ at the measured value that sends said measurement report and these two former Serving cells of the moment of Radio Link Failure take place and to be lower than first threshold; And the measured value of said switching preparation cells differs and is lower than second threshold value in said measurement report and after rebuilding; And said switching preparation cells differs at the mean value of the respective measurement values in two moment at the mean value of the measured value in two moment and former Serving cell and is higher than the 3rd threshold value, need then to confirm the handoff parameter of adjustment to comprise following one or more arbitrarily: to reduce switching threshold, reduce lagged value, reduce the reporting measuring result triggered time;
(3) if after confirming the UE handoff failure according to said incident and metrical information; Rebuild success and turn back to the sub-district before switching; And Target cell in measurement report, the measured value in these three moment differs and all is lower than the 4th threshold value during access failure and when rebuilding at random, need then to confirm the handoff parameter of adjustment to comprise following one or more arbitrarily: to increase switching threshold, increase lagged value;
(4) if after confirming the UE handoff failure according to said incident and metrical information; Rebuild success and turn back to the sub-district before switching; And the measured value of Target cell in measurement report with when the access failure at random and the respective measurement values in when reconstruction differ and all be higher than the 5th threshold value, need then to confirm the handoff parameter of adjustment to comprise: to increase the reporting measuring result triggered time.
Need to prove that in the embodiment of the invention handover optimization equipment, each unit can be concentrated in the MOS that is distributed in the network, also can disperse to be arranged in said MOS and the base station.
The incident that embodiment of the invention handover optimization equipment writes down in handoff procedure according to UE, with working frequency points and the physical layer identifications and the measured value of said incident related cell; Confirm because the handoff parameter that handoff parameter is provided with the improper handoff failure that causes and needs adjustment; Can improve the accuracy rate of confirming the handoff failure reason; And the handoff parameter that will adjust sends to and switches relevant sub-district; Make said sub-district carry out relevant parameters and optimize and revise, thereby can reduce the handoff failure probability of happening, improve user's experience.
The embodiment of the invention also provides a kind of subscriber equipment, and is as shown in Figure 4, is the structural representation of this subscriber equipment.
In this embodiment, said subscriber equipment comprises: record cell 401, transmitting element 402 and delete cells 403.Wherein:
Record cell 401, be used for writing down the handoff procedure event, with working frequency points and the physical layer identifications and the measured value of said incident related cell, concrete incident and measured value are existing in front to be specified, and repeats no more at this.
Transmitting element 402 is used for behind handoff failure, sends 401 information recorded of record cell described in this handoff procedure to network through serving BS.
Delete cells 403 is used for behind handover success, deletes 401 information recorded of record cell described in this handoff procedure.
Guarantee that for further a series of incidents of UE record are effective; And satisfying different event belongs to and has causal incident in the same handoff procedure; In embodiments of the present invention; Also can further comprise time setting unit 404, be used to effective time of every recording setting of said record cell 401.Like this, said delete cells 403 also is used for the said record of deletion after said record surpasses its effective time.
The a series of incidents and the measured value of record in the said record cell 401; Form one and switch unusual or Radio Link Failure log record; Behind the handoff failure; When between UE and base station, having RRC to be connected, said transmitting element 402 sends these records to base station, is transmitted to the SON functional entity in the network by the base station again.Such as, behind handoff failure, carry out RRC and rebuild.If RRC rebuilds successfully, UE still is in connection status, then sends these records in the network SON functional entity through the base station through new serving BS; If the RRC reconstruction failure, then UE loses connection, gets into idle condition.When initiating to connect the process of setting up again and get into connection status Deng UE, if said record still in effective time, then said transmitting element 402 just sends these records in the network SON functional entity through serving BS.If in effective time overtime after, these records still do not send the base station to, then by said delete cells 403 these records of deletion.Being provided with of said effective time can confirm flexibly, such as 1 minute or 5 minutes etc.
The subscriber equipment of the embodiment of the invention can provide effective reference information for handover optimization, makes the SON functional entity in the network confirm those because the improper switching that causes of handoff parameter is unusual or Radio Link Failure with reference to these information.
The embodiment of the invention also provides a kind of handover optimization system, and is as shown in Figure 5, is the networking sketch map of this system.
In this system, comprise: subscriber equipment 501, serving BS 502 and handover optimization equipment 503.Wherein:
Subscriber equipment 501; Be used for writing down the handoff procedure event, with working frequency points and the physical layer identifications and the measured value of said incident related cell; And behind handoff failure; Information recorded in this handoff procedure is sent to serving BS 502, concrete incident with otherwise measured value is existing in front specifies, repeat no more at this.
Handover optimization equipment 503; Be used for obtaining subscriber equipment handoff procedure information recorded from said serving BS 502; And confirm because the handoff parameter of handoff failure that handoff parameter causes and needs adjustment according to said information, the handoff parameter of needs adjustment is sent to and switches relevant sub-district.
When concrete the application; Said subscriber equipment 501 can utilize existing air interface signaling message to transmit information recorded; Also can use new dedicated signaling message to transmit, serving BS 502 is handed to handover optimization equipment 503 after receiving the recorded information of subscriber equipment 501 transmissions.In addition, said subscriber equipment 501 can also carry information recorded in the upstream data bag, after serving BS 502 is received such packet, said information recorded is extracted from said packet, hands to handover optimization equipment 503.
Need to prove, do not have geographical location information in the record if subscriber equipment 501 does not possess positioning function; So can be before handover optimization equipment 503 be handed in record by serving BS 502; The neighborhood region correlation chart that inquiry is local according to the frequency and the physical layer identifications of sub-district, obtains the overall identification of each sub-district in the record; And add in the corresponding record, so that handover optimization equipment 503 can correctly identify each sub-district.
The concrete structure of subscriber equipment in the embodiment of the invention and handover optimization equipment can repeat no more at this respectively with reference to Fig. 4 and Fig. 3 and corresponding explanatory note.
Embodiment of the invention handover optimization system; The incident that in handoff procedure, writes down according to UE, with working frequency points and the physical layer identifications and the measured value of said incident related cell; Confirm because the handoff parameter that handoff parameter is provided with the improper handoff failure that causes and needs adjustment; Can improve the accuracy rate of confirming the handoff failure reason, and the handoff parameter that will adjust sends to and switch relevant sub-district, make said sub-district carry out relevant parameters and optimize and revise; Thereby can reduce the handoff failure probability of happening, improve user's experience.
More than the embodiment of the invention has been carried out detailed introduction, used embodiment among this paper the present invention set forth, the explanation of above embodiment just is used for help understanding method and apparatus of the present invention; Simultaneously, for one of ordinary skill in the art, according to thought of the present invention, the part that on embodiment and range of application, all can change, in sum, this description should not be construed as limitation of the present invention.