Paging strategy & LAC optimization

Summary

There are several kinds of paging strategy in MSC , in order to get the high page successful rate , choose one of the page strategy is very important and necessary. Whatever page strategy need the LAC group , so setting the right LAC group is advantaged to improve the page successful rate .

Paging strategy in MSC

There are three times paging function in MSC ,it should be chose with different page strategy in every time page .the page strategy include muti-LAI page-LAI set page-BSC page-All BSC page and Intersystem page .

1. Introduce the page strategy

muti-LAI page: MSC will send the page message to those LAC which mobile register in last three times .LAI set page: MSC will send the page message to those LAC which be composed as a LAC group in MSC .BSC page: MSC will send the page message to the all of sites in a BSC which mobile register .All BSC page: MSC will send the page message to the all of the BSC that belong to the MSC which mobile register .Intersystem page: the page message will be sent to different sites which belong to different MSC at the same time .

2. How to choose the different page strategy

Actually  the page strategy is flexible ,engineer should chose the page strategy as different network topology configuration .the picture about page strategy in MSC is as follow

If the BSC that belong to same MSC are not nearby ,then this page strategy should be used as below:

First time — muti-LAI page

Second time —-LAI set page

Third time—–BSC page

If the BSC that belong to same MSC are neighbor , then this page strategy should be used as below:

First time — muti-LAI page

Second time —-LAI set page

Third time—–all BSC page

If there are some border site that belong to different MSC ,we can add one more page strategy in third times when it is necessary :

Third time—–all BSC page or BSC page and intersystem page

Note nce we use the intersystem page ,the border cell should be defined in MSC .

3. Configure the LAC group in MSC

Setting the LAC group is complex work ,which LAC should be composed as one LAC group ,we have to consult the rule as below:

• Those LAC which is near a small town should be one LAC group with town LAC together Example as below picture , the LAC1 and LAC2 should be composed as one LAC group, because there are so many border cell in this tow LAC area

• In one LAC, if all of the sites are not in border ,in other word the sites belong to different LAC have long distance each other, one LAC one LAC group is much better.

4. Step of optimize the LAC group in MSC

First step : export the data of LAC group from MSC like the table below

Second step: make a map with LAC code and BTS information in mapinfo like the map below

Third step : add or delete the LAC from LAC group by map with the rule of configure the LAC group .please consult the table below

Forth step : modify the LAC group with new LAC group in MSC.

5. Check the LAC&CI

After add the new site or rehome site ,we have to check the number of LAC & CI in MSC and BSC ,because the LAC & CI must be same in MSC and BSC. So two table that include LAC&CI should be exported from MSC and BSC,the detail is below :

1. Cell parameter table from BSC

BSC	BSSID	SYSTEM	CELLID	SID	NID	LAC	CI	PILOT_PN
Asansol1	0	2	0	14655	65535	43840	21	81
Asansol1	0	2	1	14655	65535	43840	22	249
Asansol1	0	2	2	14655	65535	43840	23	417
Asansol1	0	3	0	14655	65535	43840	31	162
Asansol1	0	3	1	14655	65535	43840	32	330
Asansol1	0	3	2	14655	65535	43840	33	498
Asansol1	0	4	0	14655	65535	43777	41	105
Asansol1	0	4	1	14655	65535	43777	42	273

2. Globe cell table from MSC

BSC	MCC	MNC	CI	LAC	Protocol Type	Border Id
Asansol BSC	404	0	51	43777	IS20001X	0
Asansol BSC	404	0	52	43777	IS20001X	0
Asansol BSC	404	0	53	43777	IS20001X	0
Asansol BSC	404	0	61	43777	IS20001X	0
Asansol BSC	404	0	62	43777	IS20001X	0
Asansol BSC	404	0	63	43777	IS20001X	0
Asansol BSC	404	0	71	43777	IS20001X	0

3. If the site has already rehomed or handovered to other MSC , delete it’s CI in “Globe cell table from MSC” is necessary .

Observe the kpi of page

We can compare with the kpi of page after optimization , generally there are three KPI we can collect in MSC and BSC ,then we can get the result .

1. Paging success ratio (%)

we can get the KPI directly in MSC and export the table as follow

Paging statistical data query template
Begin Time	Paging success ratio (%)
2008-02-07 19:00:00	83.2986
2008-02-08 19:00:00	81.9061
2008-02-09 19:00:00	84.1396
2008-02-10 19:00:00	84.2749
2008-02-11 19:00:00	84.7602
2008-02-12 19:00:00	84.3345
2008-02-13 19:00:00	84.6874
2008-02-14 19:00:00	84.5274
2008-02-15 19:00:00	84.0037
2008-02-16 19:00:00	83.865
2008-02-17 19:00:00	83.057
2008-02-18 19:00:00	83.8845
2008-02-19 19:00:00	84.2285
2008-02-20 19:00:00	82.6549

2. Paging success ratio (%)

we can get the original data(2155_1X  Global Voice Paging) in BSC ,and then calculate it by manually.

Formal : paging success ratio=( Common Call MS Paging Response Num+ Assign Soft Handoff Paging Response Num)/ Common Call MS Paging Num *100

Begin Time	Node	BSS	Common Call MS Paging Num	Common Call MS Paging Response Num	Assign Soft Handoff Paging Response Num	Paging success ratio (%)
2008-02-20 16:00:00	100001	0	106019	58349	27241	80.73
2008-02-21 16:00:00	100001	0	101009	54555	27443	81.18
2008-02-22 16:00:00	100001	0	101500	55729	27695	82.19
2008-02-23 16:00:00	100001	0	97956	53097	26682	81.44
2008-02-24 16:00:00	100001	0	93177	49552	25591	80.65
2008-02-25 16:00:00	100001	0	105300	57755	27687	81.14
2008-02-26 16:00:00	100001	0	93726	55876	27788	89.26

3. Usage ratio of page channel (%)

we can get the original data(2892_1X  Cell Control Channel Usage) in BSC ,and then calculate it by manually like the table below.

Formal : page channel usage ratio= Actual Transmit Bits of Paging Channel/Can Transmit Bits of Paging Channel*100

Begin Time	Node	BSS	BTS	Actual Transmit Bits of Paging Channel	Can Transmit Bits of Paging Channel	page channel usage ratio(%)
2008-02-27 19:00:00	100001	0	2	80556251	311011200	25.90
2008-02-27 19:00:00	100001	0	3	61616015	207331200	29.72
2008-02-27 19:00:00	100001	0	23	64030554	207340800	30.88
2008-02-27 19:00:00	100001	0	24	62790615	207331200	30.29
2008-02-27 19:00:00	100001	0	25	84347813	311040000	27.12
2008-02-27 19:00:00	100001	0	26	108424699	414662400	26.15

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