CN1949916B

CN1949916B - Method for overcoming soft handoff dropped call in third generation mobile communication system

Info

Publication number: CN1949916B
Application number: CN2005101093112A
Authority: CN
Inventors: 王亮; 周烜; 续斌
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2005-10-14
Filing date: 2005-10-14
Publication date: 2010-06-23
Anticipated expiration: 2025-10-14
Also published as: CN1949916A

Abstract

The invention advances a method for overcoming call disconnection in soft swithicng in third-generation mobile communication system, in macro diversity state, when one or plural ones of the user equipment received downlinks are outside the transmitting window, network controller removes these links; if these links qualities are certainly good, the user equipement will report their qualities by in-frequency measurement, and the network controller adds them to an activation set again, and after this, the user equipment received downlink links are bound to be inside the transmitting time window. And the method assures user equipment able to normally switch, and remarkably raises user equipment soft-switching success rate and the whole operating performance of WCDMA system.

Description

Overcome the method for soft handoff dropped call in a kind of 3-G (Generation Three mobile communication system)

Technical field

The present invention relates to the control method of a kind of soft handover in WCDMA (Wideband Code Division Multiple Access) the R99 system, refer more particularly to and in the WCDMA system, utilize the inner portable terminal transmission of user equipment (UE) (User Equipment) time of reception poor (Rx-Tx time difference) internal measurement to report the result, overcome the method for soft handoff dropped call.

Background technology

Appearance along with 3-G (Generation Three mobile communication system), soft hand-off also is applied gradually as the advantage of WCDMA system, be that travelling carriage is set up when getting in touch with new sub-district in moving process, do not interrupt immediately getting in touch, in same carrier frequency, implement soft handover and can reduce cutting off rate greatly with former sub-district.In the soft switching process, the mobile subscriber can carry out signal processing with merging from the down link signal of different districts, Here it is grand diversity receiving technology, as shown in Figure 1.

Along with the application more and more widely of mobile communcations system, grand diversity technique also is gradually improved as the key technology in this system, but still has some problems to need to solve.It is exactly one of them problem that cross-node B (NODE B) soft handover area is switched, and mainly shows as to stride just to be easy to generate call drop after NODE B soft handover is called out maintenance a period of time.Because when UE is in macro diversity status, the up delivery time of UE is not adjusted, although initial descending correctly demodulation of multilink, but along with UE moves or the drift of NODE B transmitting time, may change the time of reception of UE down link, probably causes NODE B down sending time to drop on the UE time of reception outside window, and UE is demodulation one or more down link correctly, finally cause the UE downlink quality to degenerate, until causing call drop.

When having only a link in the UE Active Set, the descending multipath adjustment that the up delivery time of UE can reach the earliest according to this link, guarantee as far as possible in the time window before down link drops on the UE delivery time time of reception, make correctly down link of demodulation of UE.Since UE move or the frequency of NODE B and UE floats, can change the time of reception of down link, the delivery time that UE has the ability by adjusting up link levels off to 1024 chips to guarantee its Rx-Tx time difference.After adding new link in the UE Active Set, network controller RNC reports to NODE B according to the UE amount of reporting and UE newly disposes, and is synchronous to realize new link and UE.Along with UE move or NODE B between the drift of clock cause change the time of reception of down link, probably drop on outside the preceding time window of UE delivery time, UE is demodulation one or more down link correctly, makes the debase of UE down link, finally might cause call drop.

The WCDMA system compares with other system (as gsm system and cdma system) many its oneself special characters, because its development time in various countries is relatively short, therefore the specific implementation aspect of handling this problem does not also have too many data to look into, in disclosed patent, also how not solve at present and stride under the NODE B macro diversity situation, time drift causes the patent of soft handover failure aspect can reference and comparison.

Adopting different soft handover implementation methods striding under the NODE B macro diversity situation, is bigger for the influence of system.The first, for improving the communication quality of part UE, realize striding NODE B soft handover and be the basic functions of one of system, otherwise might communication quality be had an immense impact on; The second, which kind of mode to realize that frequently interior soft handover could obtain best performance of handoffs by, promptly when strengthening the UE communication quality, can reduce risk of dropped calls again, this is extremely important for the performance that guarantees whole system.

Summary of the invention

The purpose of this invention is to provide the method that overcomes soft handoff dropped call in a kind of 3-G (Generation Three mobile communication system), employing sends time of reception difference Rx-Tx time difference measurement event according to user equipment (UE) inside portable terminal and triggers report judgement soft handover, has solved the problem that clock drift causes soft handover to be failed under the WCDMA system handles cross-node B macro diversity situation preferably.

Core concept of the present invention is: under macro diversity status, if user equipment (UE) receives down link when having one or more to drop on it and send outside window, network controller RNC can cut away this or multilink.If the quality of excision link is good really, UE can report its quality by frequently interior measurement report, and RNC can add it in Active Set once more, and after adding Active Set again, UE receives down link and must drop in its transmitting time window.

The method that overcomes soft handoff dropped call of the present invention may further comprise the steps:

Step 1: when subscriber equipment (UE) is in grand diversity condition following time, network controller (RNC) is opened subscriber equipment (UE) internal measurement, its measuring amount is that portable terminal sends time of reception poor (Rx-Tx time difference), and trigger mode is to trigger in Event triggered or cycle.

Step 2: the internal measurement of certain link reports and satisfies the requirement of 6f incident in subscriber equipment (UE) Active Set, this link drops on outside the time window of the up delivery time of subscriber equipment (UE) time of reception in network controller (RNC) the judgement Active Set, makes the judgement that soft handover removes this link.

Step 3: when subscriber equipment (UE) when leaving macro diversity status, network controller (RNC) is closed subscriber equipment (UE) internal measurement.

In the said method, specifically comprise in the described step 2:

1) subscriber equipment is measured according to measurement control order, and measurement result is filtered, to the CF signal assessment of measuring;

2) network controller is waited for measurement report;

When 3) satisfying condition, subscriber equipment is uploaded to network controller with measurement result;

4) whether subscriber equipment internal measurement report court verdict is to trigger thresholding 6f, if less than 6f, changes step 2 over to); If be 6f, continue step 5);

5) judge report the 6f incident link whether in Active Set, if in Active Set, continue step 6); If not in Active Set, change step 2 over to);

6) network controller judgement soft handover;

7) network controller sends the activating set updating order to subscriber equipment;

8) subscriber equipment carries out activating set updating;

9) subscriber equipment sends activating set updating to network controller and finishes message;

10) network controller sends the order of Radio Link removal request;

11) Radio Link of knot removal reported event 6f;

12) whether network controller judgement subscriber equipment Active Set number is 1, if the Active Set number is 1, carries out subsequent step; If the Active Set number greater than 1, changes step 2 over to again).

In the said method, the threshold setting of described 6f Event triggered is a 1024+T6f chip, wherein the T6f threshold value is a network controller RNC configurable parameter, through checking in a large number in the real system, can do corresponding the adjustment according to the needs of practical application and the performance of mobile phone.

As from the foregoing, the present invention is directed to that clock drift causes the soft handover Failure Causes Analysis under cross-node B (NODE B) macro diversity situation, a kind of method that triggers soft handover based on UE internal measurement reporting events is provided, guarantee that UE can normally switch, guarantee UE equipment handover success, avoided having significantly improved the overall operation performance of UE soft handover success rate and WCDMA system because factors such as NODE B equipment clock drift cause unnecessary soft handover failure.

Description of drawings

Fig. 1 be in the WCDMA system under macro diversity situation RNC handle the basic flow sheet of UE soft handover;

Fig. 2 adopts the inventive method in the WCDMA system, and RNC handles the basic flow sheet of UE soft handover under macro diversity situation;

Fig. 3 adopts the inventive method in the WCDMA system, and RNC is according to the flow chart of UE internal measurement incident judgement soft handover.

Embodiment

The invention is characterized in: therefore only need be under macro diversity status, realization gets final product the link circuit deleting that drops on the time of reception of UE down link outside its transmitting time window, remaining flow process is equivalent to a normal soft handover handling process fully, as shown in Figure 2.

The present invention makes full use of the internal measurement result that the UE Event triggered reports in the WCDMA system, in RNC, incident and measurement result that UE reported are controlled fully and adjudicated, thereby whether decision is necessary to carry out soft handover.In the WCDMA system, use the method for the invention, require UE to support that measuring amount is a Rx-Tx time difference internal measurement.After adopting the art of this patent, the basic procedure that is under the grand diversity condition can may further comprise the steps, as shown in Figure 3:

Step 110, RNC measures control (Measurement Control) order to the UE transmission, and filling in and wherein measuring sign (Measurement identity) cell is UE internal measurement config. number.The physical quantity of specified measurement, the physical quantity that reports, the filtration coefficient of measurement, the cell information of measurement in measuring control.The measurement report mode is set at that Event triggered reports mode, the quantity of the measurement report that reports, measurement report report parameters such as interval;

Step 115, UE is after receiving measurement control order, the specific requirement according in the order begins to measure, and utilizes the filtration coefficient of giving in the measurement control order that measurement result is filtered, and each CF signal of measuring is carried out comprehensive assessment;

Step 120, sign cell to be measured such as RNC is a UE internal measurement config. number, and occurs in measurement result (Measured Results) cell in measurement report (Measurement report) process of UE internal measurement result (Internal measured results) cell;

Step 125, UE is according to measuring control (Measurement Control) when event criteria is satisfied in the order request measurement, with measurement report (Measurement report) message measurement result is uploaded to RNC, sign cell to be measured such as RNC is a UE internal measurement config. number, and occurs UE internal measurement cell as a result in the measurement result cell;

Step 130, RNC equipment is according to UE internal measurement result (Internal Measured Result) cell in UE equipment reporting measurement reports (Measurement report) message.If it is EVENT6G (the UE Rx-Tx time difference of the current Active Set link of equipment is less than decision threshold) that the UE internal event indicates (Internal event identity) cell, change 120 steps over to; If it is EVENT6F (the UE Rx-Tx timedifference of the current Active Set link of equipment is greater than decision threshold) that the UE internal event indicates cell, then the RNC judgement report the 6F incident link whether in Active Set, if Active Set no longer changes step 120 over to; If at Active Set, change over to step 135 (corresponding to Fig. 3 135);

Step 135, the judgement of RNC equipment cuts the link that judgement triggers EVENT6F;

Step 140, RNC sends activating set updating (Active Set Uptate) order to UE, wherein comprises the Radio Link that reports the 6f incident, and its information appears in Radio Link deletion information (the Radio Link Removal Information) cell;

Step 145, UE is according to receiving activating set updating (Active Set Uptate) order, from Active Set, delete the Radio Link of reported event 6f according to Radio Link deletion information (RadioLink Removal Information) cell, and finish (Active Set Uptate Complete) message to RNC transmission activating set updating;

Step 150, after RNC receives that UE transmission activating set updating is finished (Active Set Uptate Complete) message, send Radio Link removal request (Radio Link Deletion Request) order to NODE B equipment, wherein comprise the Radio Link that reports the 6f incident, and its information appears in wireless link information (RL Information) cell;

Step 155, NODE B receives the Radio Link removal request order of RNC, according to the Radio Link of RL Information cell deletion reported event 6f;

Step 160, RNC receives Radio Link deletion corresponding (Radio Link Deletion Response) message that NODE B returns, whether judgement UE Active Set number is 1, if UE Active Set number is 1, changes 165 steps over to; If UE Active Set number changes step 120 over to greater than 1;

Step 165, RNC sends measurement control order to UE, discharges the UE internal measurement that is measured as Rx-Tx time difference;

This patent is not limited to the internal measurement of UE Event triggered, and the internal measurement that can trigger in the employing cycle is adjudicated the condition that whether satisfies the 6f incident by RNC.

In sum, the present invention guarantees the correctness of UE equipment Radio Link under macro diversity situation, the wireless performance index when having guaranteed the 3-G (Generation Three mobile communication system) operation by carry out the method for soft handover according to the judgement of UE internal measurement report.

Because the reliable easily row of this invention, for all relate to and stride NODE B soft switch message miscellaneous service flow process in 3-G (Generation Three mobile communication system), this invention is same to be suitable for, and can guarantee the correctness of relevant miscellaneous service flow process, improves the overall operation performance of 3-G (Generation Three mobile communication system).

Above embodiment only is used to illustrate the present invention, but not is used to limit the present invention.

Claims

1. overcome the method for soft handoff dropped call in the 3-G (Generation Three mobile communication system), it is characterized in that it may further comprise the steps:

Step 1: when subscriber equipment is in grand diversity condition following time, network controller sends measurement control order so that subscriber equipment begins to measure to subscriber equipment, its measuring amount is that portable terminal transmission time of reception is poor, and trigger mode is to trigger in Event triggered or cycle;

Step 2: the internal measurement of certain link reports and satisfies the 6f incident in the subscriber equipment Active Set, this link drops on outside the time window of the up delivery time of subscriber equipment the time of reception in the network controller judgement Active Set, makes and carries out soft handover to delete the judgement of this link;

Step 3: when subscriber equipment left macro diversity status, network controller sent measurement control order so that subscriber equipment stops to measure to subscriber equipment;

Wherein, described 6f incident is that transmitting-receiving time difference of the current Active Set link of described subscriber equipment is greater than decision threshold.

2. overcome the method for soft handoff dropped call in the 3-G (Generation Three mobile communication system) according to claim 1, it is characterized in that, specifically comprise in the described step 2:

1) described subscriber equipment is according to the described measurement control order that is sent by described network controller, and measurement result is filtered, to the CF signal assessment of measuring;

2) network controller is waited for measurement report;

3) when described subscriber equipment required measurement to satisfy event criteria according to described measurement control order, subscriber equipment was uploaded to network controller with measurement result;

6) network controller judgement soft handover;

8) subscriber equipment carries out activating set updating;

10) network controller sends the order of Radio Link removal request;

11) Radio Link of knot removal reported event 6f;

12) whether network controller judgement subscriber equipment Active Set number is 1, if the Active Set number is 1, carries out subsequent step; If the Active Set number greater than 1, changes step 2 over to again);

3. overcome the method for soft handoff dropped call in the 3-G (Generation Three mobile communication system) according to claim 1 and 2, it is characterized in that, the threshold setting of described 6f Event triggered is a 1024+T6F chip, wherein the T6f threshold value is the network controller configurable parameter, and described 6f incident is the situation of the transmitting-receiving time difference of the current Active Set link of wherein said subscriber equipment greater than decision threshold.