LAC Dimensioning Report_W20

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Location Area Dimensioning Audit in Central Region (Week 20)

Alcatel-Lucent Optimization Service Team Central

Prepared By: Muhammad Nouman Afzal

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Table Of Contents

1. Introduction: .................................................................................................................. 3

1.1 Location Area Dimensioning: ............................................................................... 3 1.2 Paging Limitations ................................................................................................ 4

1.2.1 Um interface Limit with Uncombined cells .................................................. 4 1.2.2 BSC Limit...................................................................................................... 5

2. Area definition, Analysis & recommendations: ............................................................ 5 2.1 LAC 448 ................................................................................................................ 7

2.1.1 Recommendations ......................................................................................... 9 2.2 LAC 827 ................................................................................................................ 9

2.2.1 Recommendations ....................................................................................... 11 2.3 LAC 831 .............................................................................................................. 11





2.7.1 Recommendations ....................................................................................... 21 3. Discrepancies Found ................................................................................................... 21 4. Conclusion................................................................................................................... 21

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1. INTRODUCTION:

The location area is defined by a Set of cells which are paged each time one Mobile Terminating Call or SMS is initiated in a defined area called Location Area LA . It has a unique Location Area Code (LAC), & the position of each MS on a Location Area level is stored in HLR / VLR.

The MS updates the mobile network with its latest LA using SDCCH resources in the following two cases

. When it moves from one LAC to another (Location Update)

. Periodically its current LAC position (Periodical LU).

1.1 Location Area Dimensioning:

The Location Area Size is based on a Trade off between the three following criteria s which according to their values the Location Area is decided.

Signalling load in cells located at LAC border -SDCCH resources in each cell has to be sized accordingly

Number of simultaneous paging in each cell of the LAC -All MS in LAC and in MT call are paged simultaneously

The load on the Access grant channel, which in turn limits the number of blocks used for Paging

The maximum size of a Location Area is mainly driven by the max number of paging it can handle, i.e. by the traffic seen on this Location Area. Paging messages are transmitted within CCCH blocks contained within each 51 multiframe.

There are 9 CCCH blocks per M51 frame (duration of one M51 is 235 ms) for non-combined cells. Among those 9 blocks, 9 minus BS_AG_BLK_RES are reserved for paging (BS_AG_BLK_RES=4 as a usual default value for non-combined cells giving the number of Blocks reserved for Access Grant Channel).

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There are 3 CCCH blocks per M51 frame for combined cells. Among those 3 blocks, 3 minus BS_AG_BLK_RES are reserved for paging (BS_AG_BLK_RES=1 as an usual default value for combined cells).

All cells in Mobilink Network are operating in the Non combined Mode.

Depending of the usage of IMSI or TMSI, from 1 to 4 mobiles can be paged simultaneously.

The maximum number of paging per Location Area is derived from the paging limitations at Um interface and at the BSC side

1.2 Paging Limitations

1.2.1 Um interface Limit with Uncombined cells

A 2 Paging/PCH value has been used to derive the maximum paging load per Location Area while only one user can be given an Access grant block at a time (1 AG/Block). A value of 3 paging or even 4 paging per block can be reached if and only if:

high PCH load (> 80%). The (safe) engineering limit taken later makes likely that this load is not reached. Indeed the CCCH capacity is not a linear function because of the paging request encoding method. Real time simulations performed internally show that when the 3 Paging/PCH ratio is reached we usually have a high blocking rate on PCH (about 5%), which will induce repetition by the MSC.

very good distribution of MS among all paging groups. This depends on the IMSI distribution.

Finally, we obtain the following values.

Available blocks for paging per hour:

Taking BS_AG_BLK_RES=2

7 PCH/Multiframe * (3600s / 235 ms) = 107234 PCH / hour

Paging per hour: 2 paging / Block x 107234 Blocks=214468paging/hour at 100% load. When the 70% engineering limit is applied, we obtain 150127 paging/hour, giving a 41 paging/ second value.

In turn giving an AGCH limit = 2*1*3600*(0.7)/235ms= 21447 access grant/hour, giving a 5.9 access grant/second value.

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1.2.2 BSC Limit

The BSC limit is 70 Paging/ s, i.e. 252 000 paging/hour on the A interface (Alcatel traffic model). The paging on the A interface is the sum of the paging on all Location Area which are configured on a BSC. So it depends on the Paging rate on Location Area and on the number of Location Areas in a BSC.

2. AREA DEFINITION, ANALYSIS & RECOMMENDATIONS:

The Location Area audit report Part 1 will be carried out on the Area shown below in Figure 1.

Figure 1. Area being Audit

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The Area includes the following BSCs mentioned in Table 1 below, an Audit shall be submitted for each Location Area which shall include Auditing on the Paging Load on the UM interface, Paging load on the BSS side & AGCH load.

BSC Name Location Area Code

MGH481A__Muzaffar_3 448 MGH480A__Muzaffar_1 448

BKR471A__Nazirtwn 827 BKR472A__Godala 827

BKR469A__MasjidUmer 827 KNL462A__Gnawaz_1 831 KNL463A__Gnawaz_2 831

KNL450A__Shabnamcine

836 KNL449A_Civillines 836

KNL561A__Kachakhu 838 KNL562A__Civillines_2 838 MLS508A__VehariRd_1 853

MLS510A__Mozadin 853 VHR511A__RailwaySt_1 855 VHR564A__RailwaySt_2 855

Table 1. Area Definition

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2.1 LAC 448

Figure 2.1 LAC 448


MGH481A__Muzaffar_3

448 MGH480A__Muzaffar_1

448 Table 2.1 LAC 448

Since BS_AG_BLK_RES = 2 on all cells of these 2 BSCs Then AGCH limitation at 70% engineering limit = 21447 access grant/hour & Paging limitation at 70% engineering limit = 150127 paging/hour

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Figure 2.1.1 AGCH Load

As per figure 2.1.1, all cells belonging to LAC 448 have an AGCH load below the threshold defined according to the value of the parameter BS_AG_BLK_RES.

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HWY3959A__S_MNKQaziabad (LAC =448, CI = 13959) (notplanned) 448 13959MGH481A__Muzaffar_3

HWY3959B__S_MNKQaziabad (LAC =448, CI = 23959) (notplanned) 448 23959MGH481A__Muzaffar_3

HWY3959C__S_MNKQaziabad (LAC =448, CI = 33959) (notplanned) 448 33959MGH481A__Muzaffar

Figure 2.1.2 Paging Load

As per figure 2.1.2, all cells belonging to LAC 448 have a Paging load well below the threshold defined according to the value of the parameter BS_AG_BLK_RES. Also all cells are having the same exact Paging, showing that there is no error in their creation from the NSS end except one or two hours

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HWY3959A__S_MNKQaziabad (LAC =448, CI = 13959) (notplanned) 448 13959MGH481A__Muzaffar_3

HWY3959B__S_MNKQaziabad (LAC =448, CI = 23959) (notplanned) 448 23959MGH481A__Muzaffar_3

HWY3959C__S_MNKQaziabad (LAC =448, CI = 33959) (notplanned) 448 33959MGH481A__Muzaffar

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2.1.1 Recommendations

No Change in design for LAC 448 is needed as both the Paging load (on Um & BSS sides) & AGCH load are well below threshold.

2.2 LAC 827

Figure 2.2 LAC 827


BKR471A__Nazirtwn 827 BKR472A__Godala 827

BKR469A__MasjidUmer

827 Table 2.2 LAC 827


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BHL4879A__S_MCBBehal (LAC = 827, CI= 14879) (notplanned) 827 14879BKR471A__Nazirtwn

BHL4879B__S_MCBBehal (LAC = 827, CI= 24879) (notplanned) 827 24879BKR471A__Nazirtwn

BHL4879C__S_MCBBehal (LAC = 827, CI= 34879) (notplanned) 827 34879BKR471A__Nazirtwn


As per figure 2.2.1, all cells belonging to LAC 827 have an AGCH load below the threshold defined according to the value of the parameter BS_AG_BLK_RES.Only one cell did the violation for few hours,but it seems unreal stats as the trend has been quite normal throughout the week.

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BHL4879A__S_MCBBehal (LAC = 827, CI= 14879) (notplanned) 827 14879BKR471A__Nazirtwn

BHL4879B__S_MCBBehal (LAC = 827, CI= 24879) (notplanned) 827 24879BKR471A__Nazirtwn

BHL4879C__S_MCBBehal (LAC = 827, CI= 34879) (notplanned) 827 34879BKR471A__Nazirtwn


As per figure 2.1.2, all cells belonging to LAC 827 have a Paging load below the threshold defined according to the value of the parameter BS_AG_BLK_RES.

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However the cell DRK4983C_S_Yarasula had the highest paging of 143,803 which is quite close to the threshold of 70%.This LAC might need a review in the near future because of this cell. All cells are having the same exact Paging, showing that there is no error in their creation from the NSS end.However some cells had different values due to stuck stats and sometimes Abis fluctuations


No Change in design for LAC 827 is needed as both the Paging load (on Um & BSS sides) & AGCH load are well below threshold. .

2.3 LAC 831

Figure 2.3 LAC 831


KNL462A__Gnawaz_1

831 KNL463A__Gnawaz_2

831 Table 2.3 LAC 831

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HWY3217A__H_JHNChowkMetla (LAC =831, CI = 13217) (notplanned) 831 13217KNL462A__Gnawaz_1

HWY3217B__H_JHNChowkMetla (LAC =831, CI = 23217) (notplanned) 831 23217KNL462A__Gnawaz_1

HWY3217C__H_JHNChowkMetla (LAC =831, CI = 33217) (notplanned) 831 33217KNL462A__Gnawaz_


As per figure 2.3.1, all cells belonging to LAC 831 have an AGCH load below the threshold defined according to the value of the parameter BS_AG_BLK_RES except one cell HWY8547A__S_BastiTaraggar which sometimes crosses the threshold.So please change its Cell_reselect_hysteresis from 0 to 5.

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HWY3217A__H_JHNChowkMetla (LAC =831, CI = 13217) (notplanned) 831 13217KNL462A__Gnawaz_1

HWY3217B__H_JHNChowkMetla (LAC =831, CI = 23217) (notplanned) 831 23217KNL462A__Gnawaz_1

HWY3217C__H_JHNChowkMetla (LAC =831, CI = 33217) (notplanned) 831 33217KNL462A__Gnawaz_


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As per figure 2.3.2, all cells belonging to LAC 831 have a Paging load below the threshold defined according to the value of the parameter BS_AG_BLK_RES. Also all cells are having the same exact Paging, showing that there is no error in their creation from the NSS end.However for some cells stats showed some errors



2.4 LAC 836

Figure 2.4 LAC 836


KNL450A__Shabnamcine

836 KNL449A_Civillines 836

Table 2.4 LAC 836

Since BS_AG_BLK_RES = 2 on all cells of this BSC Then AGCH limitation at 70% engineering limit = 21447 access grant/hour & Paging limitation at 70% engineering limit = 150127 paging/hour

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HWY4028A__S_asitDingaPul (LAC =836, CI = 14028) (notplanned) 836 14028KNL449A_Civillines

HWY4028B__S_asitDingaPul (LAC =836, CI = 24028) (notplanned) 836 24028KNL449A_Civillines

HWY4028C__S_asitDingaPul (LAC =836, CI = 34028) (notplanned) 836 34028KNL449A_Civillines



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HWY4028A__S_asitDingaPul (LAC =836, CI = 14028) (notplanned) 836 14028KNL449A_Civillines

HWY4028B__S_asitDingaPul (LAC =836, CI = 24028) (notplanned) 836 24028KNL449A_Civillines

HWY4028C__S_asitDingaPul (LAC =836, CI = 34028) (notplanned) 836 34028KNL449A_Civillines


As per figure 2.4.2, all cells belonging to LAC 836 have a Paging load below the threshold defined according to the value of the parameter BS_AG_BLK_RES. Also all cells are having the same exact Paging, showing that there is no error in their creation from the NSS end.

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2.5 LAC 838

Figure 2.5 LAC 838


KNL561A__Kachakhu 838 KNL562A__Civillines_2

838

Table 2.5 LAC 838

Since BS_AG_BLK_RES = 2 on all cells of this BSC Then AGCH limitation at 70% engineering limit = 21447 access grant/hour & Paging limitation at 70% engineering limit = 150127 paging/hour

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ABH4291A__H_KBRAbdulHakeem (LAC= 838, CI = 14291)(not planned) 83814291KNL562A__Civillines

ABH4291B__H_KBRAbdulHakeem (LAC= 838, CI = 24291)(not planned) 83824291KNL562A__Civillines

ABH4291C__H_KBRAbdulHakeem (LAC= 838, CI = 34291)(not planned) 83834291


As per figure 2.5.1, all cells belonging to LAC 838 have an AGCH load below the threshold defined according to the value of the parameter BS_AG_BLK_RES.Only one cell crossed the 70% value however it was only for one hour, otherwise the trend is quite normal.

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ABH4291A__H_KBRAbdulHakeem (LAC= 838, CI = 14291)(not planned) 83814291KNL562A__Civillines

ABH4291B__H_KBRAbdulHakeem (LAC= 838, CI = 24291)(not planned) 83824291KNL562A__Civillines

ABH4291C__H_KBRAbdulHakeem (LAC= 838, CI = 34291)(not planned) 83834291


As per figure 2.5.2, all cells belonging to LAC 838 has a Paging load below the threshold defined according to the value of the parameter BS_AG_BLK_RES. Also all cells are having the same exact Paging, showing that there is no error in their creation from the NSS end, the value has fluctuated on some cells over the last day of the analysis due to some Abis Fluctuations.

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2.6 LAC 853

Figure 2.6 LAC 853


MLS508A__VehariRd_1

853 MLS510A__Mozadin 853

Table 2.6 LAC 853


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FPR8453A__S_KarorPakkaRoad (LAC =853, CI = 18453) (notplanned) 853 18453MLS508A__VehariRd_1

FPR8453B__S_KarorPakkaRoad (LAC =853, CI = 28453) (notplanned) 853 28453MLS508A__VehariRd_1

FPR8453C__S_KarorPakkaRoad (LAC =853, CI = 38453) (notplanned) 853 38453MLS508A__VehariRd



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FPR8453A__S_KarorPakkaRoad (LAC =853, CI = 18453) (notplanned) 853 18453MLS508A__VehariRd_1

FPR8453B__S_KarorPakkaRoad (LAC =853, CI = 28453) (notplanned) 853 28453MLS508A__VehariRd_1

FPR8453C__S_KarorPakkaRoad (LAC =853, CI = 38453) (notplanned) 853 38453MLS508A__VehariRd


As per figure 2.6.2, all cells belonging to LAC 853 has a Paging load below the threshold defined according to the value of the parameter BS_AG_BLK_RES. Also all cells are having the same exact Paging, showing that there is no error in their creation from the NSS end.

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2.7 LAC 855

Figure 2.6 LAC 855


VHR511A__RailwaySt_1

855 VHR564A__RailwaySt_2

855 Table 2.6 LAC 855


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Bdw7506A__S_Chak216_E-B (LAC = 855,CI = 17506) (notplanned) 855 17506VHR511A__RailwaySt_1

Bdw7506B__S_Chak216_E-B (LAC = 855,CI = 27506) (notplanned) 855 27506VHR511A__RailwaySt_1

Bdw7506C__S_Chak216_E-B (LAC = 855,CI = 37506) (notplanned) 855 37506VHR511A__RailwayS


As per figure 2.6.1, all cells belonging to LAC 855 have an AGCH load below the threshold defined according to the value of the parameter BS_AG_BLK_RES except PKM8469B__S_AddaPakhiMor which violated the threshold only for one hour but that seems unreal.

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Bdw7506A__S_Chak216_E-B (LAC = 855,CI = 17506) (notplanned) 855 17506VHR511A__RailwaySt_1

Bdw7506B__S_Chak216_E-B (LAC = 855,CI = 27506) (notplanned) 855 27506VHR511A__RailwaySt_1

Bdw7506C__S_Chak216_E-B (LAC = 855,CI = 37506) (notplanned) 855 37506VHR511A__RailwayS


As per figure 2.6.2, all cells belonging to LAC 855 has a Paging load below the threshold defined according to the value of the parameter BS_AG_BLK_RES. Also all cells are having the same exact Paging, showing that there is no error in their creation from the NSS end.

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3. DISCREPANCIES FOUND

No discrepancies were found during the Audit that need to be corrected.

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4. CONCLUSION

Location Area dimensioning Audit was performed on 7 LACs in Alcatel-Lucent C2 region. No LACs violated the dimensioning rules on the CCCH (regarding the paging channel load.

However paging load was quite normal for all the LACs. So it was not possible to propose any LAC mergers.

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LAC Dimensioning Report_W20