CN101674627A - Process method of GSM cell switching and system thereof - Google Patents

Abstract

The invention discloses a process method of GSM cell switching, comprising the steps of: judging whether the cell is taken as a candidate switching object cell according to that whether the duration time that the receiving level of the adjoining cells is higher than a preset value is over a set threshold value T; and if the duration time is over the threshold value T, the cell is taken as the candidate switching object cell. The invention also discloses a process system of GSM cell switching. By judging whether the duration time that the receiving level of the adjoining cells is higher than the preset value is over the set threshold value T when switching, the invention can prevent from taking the cell which generates short strong signals caused by signal leakage and drift under some special scenes to be as the candidate switching object cell, thus preventing from error switching caused thereby.

Description

A kind of GSM sub-district switching processing method and system

Technical field

The present invention relates to moving communicating field, relate in particular to switching processing method and system in sub-district among the GSM.

Background technology

The so-called switching in the mobile communication, be meant that working as travelling carriage moves to another base station overlay area from a base station overlay area in communication process, when perhaps causing speech quality to descend owing to external interference, must change original voice channel and be transferred to a new idle voice channel and get on, to continue to keep the process of conversation.Handoff algorithms has multiple, comprises switching based on level, based on the switching of quality, based on the switching of distance, based on the switching of speed, based on the switching of path loss and grand little switching or the like.

One of trigger condition that produces switching is BSS (Base-Station Sub-System: base station sub-system) receive from mobile station MS (Mobile Station: measurement report travelling carriage).Behind the measurement report of receiving MS, information such as the level of level, quality information and the peripheral adjacent sub-district of the Serving cell that BSS reports according to MS and quality, according to certain handoff algorithms, whether adjudicate this MS should initiate to switch, BSS will select switching candidate target cells according to certain algorithm from the adjacent area simultaneously, and from candidate target cells, select final switching target small area by certain sort method, initiate switching flow then.

When the select target sub-district, relate to the processing and the judgement of the adjacent area level value that BSS measures MS.In general, the every 480ms of MS reports the one-shot measurement report, and BSS need carry out preliminary treatment to the measurement report of MS.The moving average method is generally adopted in preliminary treatment.So-called moving average method is exactly when new measurement data, gives up data the oldest in averaging process last time, adds up-to-date data, participates in average data like this and keeps identical number always, just the size of sliding window.The data of having only accumulative total just begin the process of average computation during more than a sliding window.Formula is shown in (1):

$\mathrm{AvRx}\left(n\right)=\frac{\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}\mathrm{Rx}\left(i\right)}{N}---\left(1\right)$

Wherein n represents n sampled point (n the measurement report that MS reports), and AvRx (n) is illustrated in the descending collection of letters average level of this sub-district that this sampled point calculates, and Rx (n) is illustrated in the descending level value of this sub-district that MS reports in this measurement report.

Whether BSS will use the level value of Serving cell level value, signal quality value and adjacent area after the moving average comprehensively to judge, should initiate to switch and to which adjacent area initiate to switch in conjunction with the judgement of information summaries such as native region priority, cell load.

In existing neighboring area signal level sliding window preprocessing process and switch decision process, the mistake switching problem that the of short duration strong signal that produces because of the signal leakage of some sub-district, drift under the part special screne causes is difficult to solve, and therefore need basic handoff algorithms be optimized.Below this scene is described for example.

As shown in Figure 1, sub-district B and C are the adjacent area of sub-district A, and B and A have the intersection overlay area, and the intersection overlay area is the arterial traffic between A and the B; C and A also have the intersection overlay area, and the intersection overlay area is the arterial traffic between A and the C.Certain some K of arterial traffic between A and B, signal passing through building E and the slit between the building F of sub-district C cover the K point.When travelling carriage along the arterial highway between A and the B from A when B moves, when travelling carriage arrives the K point, we do not wish that the switching from A to C takes place this travelling carriage.But because the C cell signal of ordering at K is very strong, the level changing value of the C sub-district that the MS of ordering at K measures as shown in Figure 2; Be easy to trigger the switching from A to C like this, and this be we do not wish to take place.

Want at the K point switching from A to C not to take place, effective method comprises the handoff threshold value of revising adjacent area C, but will inevitably have a strong impact on the switching effect of travelling carriage when move the arterial highway from A to C like this.Other method is to revise the size of sliding window N of the average level value of calculation plot C; By being provided with N more greatly, the high signal level of some blinks will be offset by long-time moving average like this, thereby can avoid this sub-district judgement is candidate handover cell; But the defective of this algorithm is can not be cancelled effectively for the very strong signal level of part burst.

Summary of the invention

The technical problem to be solved in the present invention is that a kind of GSM sub-district switching processing method and system that can prevent effectively that mistake from switching is provided.

Technical problem of the present invention is solved by the following technical programs:

A kind of GSM sub-district switching processing method, comprise: whether whether the duration that is higher than predetermined value according to abutting subdistrict collection of letters level surpass setting threshold T and judge described sub-district as the candidate handover target sub-district, if surpass then as the candidate handover target sub-district.

Above-mentioned decision process specifically is higher than described predetermined value by the collection of letters level that judges whether continuous K report in described setting threshold T, T=K * measurement report cycle wherein, if the then described duration surpass described setting threshold T.

Above-mentioned moving average method is handled and is specifically calculated by following formula:

$\mathrm{AvRx}\left(n\right)=\frac{\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}\mathrm{Rx}\left(i\right)}{N}$

Wherein n represents n measurement report, and N represents the reporting quantities in the sliding window.

A kind of GSM sub-district switching processing system, comprise detection module, whether described detection module is used for whether surpassing setting threshold T according to the duration that abutting subdistrict collection of letters level is higher than predetermined value and judges described sub-district as the candidate handover target sub-district, if surpass then as the candidate handover target sub-district.

Above-mentioned collection of letters level predetermined value is the collection of letters level threshold of presetting.

Above-mentioned detection module is used for also judging whether that the collection of letters level of continuous K report is higher than described predetermined value in described setting threshold T, T=K * measurement report cycle wherein, if the then described duration surpass described setting threshold T.

The collection of letters level of above-mentioned report is the value that adopts after the moving average method is handled.

The value that above-mentioned moving average method is handled is meant by following formula to be calculated:

$\mathrm{AvRx}\left(n\right)=\frac{\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}\mathrm{Rx}\left(i\right)}{N}$

Calculate the value that obtains, wherein n represents n measurement report, and N represents the reporting quantities in the sliding window.

The present invention's beneficial effect compared with prior art is:

The present invention is by increasing the judgement whether duration that abutting subdistrict collection of letters level is higher than predetermined value surpasses setting threshold T when switching, the sub-district that so just can avoid producing of short duration strong signal because of signal leakage, drift under the part special screne is as the candidate handover target sub-district, thereby the mistake of avoiding bringing is thus switched.

Description of drawings

Fig. 1 is an application scenarios schematic diagram of the present invention;

Fig. 2 is that the C cell signal level of ordering at K when MS moves in the application scenarios of the present invention changes schematic diagram;

Fig. 3 is a kind of embodiment flow chart of the inventive method;

Fig. 4 is that level after the C cell signal moving average that K is ordered changed schematic diagram when MS moved in the application scenarios of the present invention.

Embodiment

In conjunction with the accompanying drawings the present invention is described in further details with embodiment below.

The present invention relates to a kind of optimized Measures of handoff algorithms in global system for mobile communications GSM, at BSS to PBGT (Power Budget: the power budget handoff algorithms) switch, when selecting candidate target cells in based on the switching of level, based on the handoff algorithms such as switching of quality, whether whether the duration that is higher than predetermined value by collection of letters level surpass setting threshold T and judge described sub-district as the candidate handover target sub-district, if surpass then as the candidate handover target sub-district.Solve the problem that issuable mistake is switched under some special screne.

GSM of the present invention sub-district switching processing system, its a kind of embodiment, comprise detection module, whether detection module is used for whether surpassing setting threshold T according to the duration that abutting subdistrict collection of letters level is higher than predetermined value and judges described sub-district as the candidate handover target sub-district, if surpass then as the candidate handover target sub-district.

This collection of letters level predetermined value is the collection of letters level threshold of presetting.

This detection module is used for also judging whether that the collection of letters level of continuous K report is higher than predetermined value in described setting threshold T, T=K * measurement report cycle wherein is if then the duration surpasses setting threshold T.

The collection of letters level of this report is the value that adopts after the moving average method is handled.

The value that this moving average method is handled is meant by following formula to be calculated:

$\mathrm{AvRx}\left(n\right)=\frac{\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}\mathrm{Rx}\left(i\right)}{N}$

Calculate the value that obtains, wherein n represents n measurement report, and N represents the reporting quantities in the sliding window.

GSM of the present invention sub-district switching processing method, its a kind of embodiment comprises:

Whether whether the duration that is higher than predetermined value according to abutting subdistrict collection of letters level surpass setting threshold T and judge described sub-district as the candidate handover target sub-district, if surpass then as the candidate handover target sub-district.

This collection of letters level predetermined value is the collection of letters level threshold of presetting.

This decision process specifically is higher than predetermined value by the collection of letters level that judges whether continuous K report in setting threshold T, and T=K * measurement report cycle wherein is if then the duration surpasses described setting threshold T.

The collection of letters level of this report is the value that adopts after the moving average method is handled.Promptly calculate by following formula:

$\mathrm{AvRx}\left(n\right)=\frac{\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}\mathrm{Rx}\left(i\right)}{N}$

Wherein n represents n measurement report, and N represents the reporting quantities in the sliding window.

The another kind of execution mode of processing method of the present invention, its flow process may further comprise the steps as shown in Figure 3:

Step 301:MS reporting measurement reports; The MS reporting measurement reports is given BSS, the time interval that reports and the quantity of abutting subdistrict can be provided with as required, in this embodiment, every 480ms reports the descending level value, received signal quality value of Serving cell and the down receiving signal level value of the strongest 6 abutting subdistricts.

Step 302:BSS preliminary treatment; BSS is according to the selection of measurement report and different handoff algorithms (collection), and the descending incoming level signal quality of up/descending level value, received signal quality value and the abutting subdistrict of the Serving cell in the measurement report is carried out preliminary treatment.Such as, when the handoff algorithms selected based on descending level, then at first need descending level to the Serving cell that comprises in the measurement report to carry out moving average and calculate, adjudicate according to sliding average then whether needs trigger switches.

Step 303:BSS produces the candidate cell tabulation; When finding to need to initiate to switch, will carry out the process of selecting candidate target cells.The selection of candidate target cells comprises the cell downlink collection of letters level that hierarchical relationship, telephone traffic level and the MS of needs investigation minizone report etc.Through after this process, BSS will produce a candidate handover cell tabulation from the adjacent area table of Serving cell.

Step 304: be K AvRx (n) all above collection of letters level threshold continuously? based on what use always at present the adjacent area level is adopted the average scheme of N bit slip, collection of letters level predetermined value and duration setting threshold T at each adjacent area judge, in the present embodiment, this collection of letters level predetermined value and duration setting threshold T are embodied as collection of letters level threshold and abutting subdistrict collection of letters level duration two parameters respectively, whether these two parameters are used for the judging process of this abutting subdistrict as the candidate handover target sub-district, only when the duration that the level of this abutting subdistrict is higher than threshold value surpasses " duration of the collection of letters level of abutting subdistrict " that is provided with, just permission with this abutting subdistrict as the candidate handover target sub-district.This algorithm and N bit slip average algorithm use jointly; Need calculate AvRx (n) according to N bit slip averaging method, then a continuous K AvRx (n) value be judged, wherein T=K * measurement report cycle; Judge whether that a continuous K AvRx (n) value all above collection of letters level threshold, is then to change step 305, otherwise changes step 306 over to.

Step 305: list the candidate cell tabulation in; The level duration of this sub-district is not of short duration, can list the candidate handover target cell list in, carries out next step switch decision.

Step 306: do not carry out next step judgement; The level duration of this sub-district is of short duration, no longer carries out switch decision.

Under the scene of Fig. 1, we can be provided with higherly the duration of the Target cell collection of letters level of C sub-district (concrete value can obtain according to on-the-spot test), like this when travelling carriage at A to the path of B during through place K, although there is the signal of (the concrete time is depended on the width between user moving speed and building E and F) C in the of short duration time stronger, but because the duration of the Target cell collection of letters level that the C sub-district is provided with, it is also just long to trigger the time decision of switching, and the mistake that so just can not trigger from A to C is switched.

Concrete being provided with is as follows: open the handoff functionality based on descending level of sub-district A → sub-district C, moving average window N value=4 to sub-district C are set; The PBGT handoff threshold value that A → C is set is 4dB.According to the actual measurement of ordering at K (moving to the C sub-district from the A sub-district), the level value after moving average of A sub-district is-85dBm.The level value of the C sub-district that MS reports as shown in Figure 2.

Set the duration T=8s of abutting subdistrict collection of letters level, collection of letters level threshold=-80dBm.

By the moving average algorithm, the average level value of C sub-district as shown in Figure 4, the time span that C sub-district level intensity continues to be better than collection of letters level threshold-80dBm is 5s, duration T (8 seconds) less than abutting subdistrict collection of letters level, even therefore the level of C sub-district surpasses A sub-district level promptly greater than 4dB (PBGT thresholding), the PBGT that also can not trigger from A to C switches.

Above content be in conjunction with concrete preferred implementation to further describing that the present invention did, can not assert that concrete enforcement of the present invention is confined to these explanations.For the general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, can also make some simple deduction or replace, all should be considered as belonging to protection scope of the present invention.

Claims (10)

1. a GSM sub-district switching processing method is characterized in that, comprising:

Whether whether the duration that is higher than predetermined value according to abutting subdistrict collection of letters level surpass setting threshold T and judge described sub-district as the candidate handover target sub-district, if surpass then as the candidate handover target sub-district.

2. the method for claim 1 is characterized in that, described predetermined value is the collection of letters level threshold of presetting.

3. method as claimed in claim 1 or 2, it is characterized in that, described decision process specifically is higher than described predetermined value by the collection of letters level that judges whether continuous K report in described setting threshold T, T=K * measurement report cycle wherein, if the then described duration surpass described setting threshold T.

4. method as claimed in claim 3 is characterized in that, the collection of letters level of described report is the value that adopts after the moving average method is handled.

5. method as claimed in claim 4 is characterized in that, described moving average method is handled and specifically calculated by following formula:

$\mathrm{AvRx}\left(n\right)=\frac{\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}\mathrm{Rx}\left(i\right)}{N}$

Wherein n represents n measurement report, and N represents the reporting quantities in the sliding window.

6. GSM sub-district switching processing system, it is characterized in that, comprise detection module, whether described detection module is used for whether surpassing setting threshold T according to the duration that abutting subdistrict collection of letters level is higher than predetermined value and judges described sub-district as the candidate handover target sub-district, if surpass then as the candidate handover target sub-district.

7. system as claimed in claim 6 is characterized in that, described predetermined value is the collection of letters level threshold of presetting.

8. as claim 6 or 7 described systems, it is characterized in that, described detection module is used for also judging whether that the collection of letters level of continuous K report is higher than described predetermined value in described setting threshold T, T=K * measurement report cycle wherein, if the then described duration surpass described setting threshold T.

9. system as claimed in claim 8 is characterized in that, the collection of letters level of described report is the value that adopts after the moving average method is handled.

10. system as claimed in claim 8 is characterized in that, the value that described moving average method is handled is meant by following formula to be calculated:

$\mathrm{AvRx}\left(n\right)=\frac{\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}\mathrm{Rx}\left(i\right)}{N}$

Calculate the value that obtains, wherein n represents n measurement report, and N represents the reporting quantities in the sliding window.

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