Drop Call Reduction Strategy 1.0

FIELD GUIDE 1 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05

Drop Call Rate Reduction Strategy

Owner: James Michael Ledesma [email protected] Scope: Discusses various strategies used to improve the DCR Originator: Status: Draft Document ID: Location: Atlanta

Change History

Issue Date Handled by Comments 0.01 04/13/05 Michael Ledesma Document Creation 0.02

04/15/05 Michael Ledesma Feedback from Regions

added in the document. 1.0 04/16/05 Michael Ledesma Changes to graphs, and

parameter baseline in Detroit was added. Official Release

Approved by

04/13/05 Physon Nguyen Timo Halonen

FIELD GUIDE 2 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 1. Introduction .................................................................................................................................... 3 2. Where do we start? ........................................................................................................................ 3

2.1 Network Assessment Are We Coverage or Interference Limited? ........................................ 4 2.1.1 Coverage Limited Network ............................................................................................... 4 2.1.2 Interference Limited Network ........................................................................................... 5 2.1.3 What Strategies Fit Which Network?................................................................................ 6

3. Main Strategies .............................................................................................................................. 7 3.1 HO Management In A Multi BCCH Environment ..................................................................... 7

3.1.1 Control Over Shooting Cells............................................................................................. 7 3.1.2 Improve Indoor Coverage................................................................................................. 8 3.1.3 Optimize Multi layer Handovers ....................................................................................... 9 3.1.3.1 Umbrella Ho Vs Traffic Reason HO............................................................................ 11 3.1.4 Trial Results in LA .......................................................................................................... 11 3.1.5 Handover Optimization Recommended Parameter Settings (Summary) ....................... 12

3.2 AMR HR OPTIMIZATION...................................................................................................... 13 3.2.1 Recommended Parameter Settings for 70% HR Usage ................................................ 13 3.2.2 Trial Results in LA .......................................................................................................... 14 3.2.3 DL FER and C/I Performance for 85% HR Usage in Detroit .......................................... 15 3.2.4 MAXCAP Feature........................................................................................................... 16

4. Appendix : Performance Charts ................................................................................................... 17 4.1 Indoor Coverage.................................................................................................................... 17 4.2 HO Management In A Multi BCCH Environment ................................................................... 18 4.3 AMR Downlink FER and RXQUAL (Detroit) .......................................................................... 19 4.4 DL AMR HR C/I Distribution Curve (Detroit).......................................................................... 20 4.5 AMR Codec Distribution (LA Trial) ........................................................................................ 21 4.6 EFL Formula:......................................................................................................................... 22 4.7 Example Of XY Scatter Plot for DCR vs Ave Erlang/Cell ...................................................... 22

FIELD GUIDE 3 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 1. INTRODUCTION

This document was created to provide the engineer with a general guideline on how to improve the Drop Call Rate of the existing network. The techniques and solutions provided in this document give a general direction to the engineer so that they can focus on their optimization efforts effectively. These techniques and solutions are a product of the optimization learnings gained from trials conducted in different live networks. Basic day-to-day optimization activities will not be discussed here. 2. WHERE DO WE START?

Aside from the day-to-day optimization activities we have some main strategies that we can use to reduce the drop call rate. But in order to achieve the drop call rate improvement we need to do the following:

Assess if you are Coverage or Interference Limited Select the strategies that are applicable for your network type Implement the strategies and optimize the parameters related to that particular strategy

FIELD GUIDE 4 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 2.1 Network Assessment Are We Coverage or Interference Limited?

It is important to know if the network we are optimizing is coverage or interference limited. Knowing this information would impact the general direction of the optimization efforts and the solutions available

2.1.1 Coverage Limited Network

Coverage limited network is typically characterized by: Low EFL Constant drop call rate despite increase/decrease in Erlang traffic

Activities are more focused on:

Adding more sites and TMAs Antennal Changeouts and Downtilt Adjustment

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Average Erlangs/cell

dcr8

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Baseline - HR%=20% TestCase 1.0 - HR%=85% Log. (Baseline - HR%=20%) Log. (TestCase 1.0 - HR%=85%)

Figure 1: Using Hourly DCR8C and Erlang traffic per cell on a BSC, you can generate the scatterplot graph above and run a logarithmic trend line to determine if you have a flat trend indicating a that you have a coverage limited network.

FIELD GUIDE 5 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 2.1.2 Interference Limited Network

Interference limited network is typically characterized by:

High EFL Drop call rate is proportional to the increase/decrease in Erlang traffic

Activities are more focused on

Interference Management Antenna Changeouts and Downtilt Adjustment Optimize current frequency plan

Figure 2: Using Hourly DCR8C and Erlang traffic per cell on a BSC, you can generate the scatter plot graph above and run a logarithmic trend line to determine if you have a positive sloping trend indicating a that you have an interference limited network. The steeper the slope the more interfered the network

FIELD GUIDE 6 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 2.1.3 What Strategies Fit Which Network?

Strategies Discussed

Applicable to Coverage

Limited

Applicable to Interference

Limited Applicable to Multi BCCH

Applicable to CBCCH

Applicable to Single Band

HO Management in a Multi BCCH environment Y Y Y N Y

AMR HR Optimization Y Y Y Y Y If your network were truly Coverage Limited there would be no impact to the DCR thus HR optimization would not be applicable. The strategies outlined for the single layer can be used to improve the handovers and ultimately the drop call performance. As of today CBCCH optimization trials have just started. Recommendations to improve CBCCH multi band strategies will be included in future revisions.

FIELD GUIDE 7 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 3. MAIN STRATEGIES

There are 2 strategies that we use to improve the drop call rate

Manage HO Related Drops In A Multi BCCH Environment AMR HR Optimization

3.1 HO Management In A Multi BCCH Environment

This strategy improves the drop call rate by reducing the handover related drops in a multi BCCH environment. The activities focus on the following objectives:

Control Over Shooting Cells

o Reduce the interference and island coverage created by overshooting cells

Improve Indoor Coverage

o Move indoor traffic to the 850 layer since it has better coverage than the 1900 layer using Traffic Reason HO (TRHO)

Optimize Multi layer Handovers

o Control the traffic load on each layer with TRHO to keep traffic on 850 and move to 1900 only when the load threshold is met

o Reduce the number of unnecessary handovers

3.1.1 Control Over Shooting Cells

Below are the steps taken to control overshooting cells:

1. Identify Worst Offenders 2. Compare # drops 1900 Vs. 850 3. Compare ERP 4. Compare Timing Advance (TA) 5. Adjust PMAX in order to match ERP of 850 to ERP 1900 6. Check Stats after the PMAX change 7. Review and either start again from step 1. Or suggest DOWNTILT


Figure 3 below shows the improvement after an over shooting cell was adjusted to control interference.

Figure 3: Improvements after adjusting an overshooting cell.

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3.1.2 Improve Indoor Coverage

To improve indoor coverage in an MBCCH environment, Traffic Reason HO is used to:

1. Keep the traffic on the 850 layer (better coverage) by adjusting:

a. AUT = AMH Upper Load Threshold to trigger BSC TRHO b. AML = AMH Max Load of Target cell for TRHO c. TRHO = Min RxLev of Target cell for TRHO

2. Avoid useless handovers in low signal strength conditions that lead to drop calls


3.1.3 Optimize Multi layer Handovers

These are the steps taken to optimize multi layer handovers

1. Reduce the number of unnecessary handovers

a. Remove Level HO

b. Increase HO Margins

i. PBGT

1. Intra-site (intra-layer) => 6 dB

2. Inter-site (intra-layer) => 4 dB

ii. LMRG = 24 dB (disabled)

iii. QMRG = 3 dB

2. Use more Quality HO

3. Use Traffic Reason HO rather than Umbrella HO

4. Use Level HO only to move from 1900 to 850 in collocated sectors

Macro GSM850 Macro GSM850

Macro GSM1900

Collocated BTSs (same azimuth A Vs. X or B Vs. Y or C Vs. Z)

UL RX Quality HODL Rx Quality HO

PBGT



Macro GSM1900

UL Rx Level HODL Rx Level HO



TRAFFIC HO

PBGT


Macro GSM850 Macro GSM850

Macro GSM1900



PBGT



Macro GSM1900

UL Rx Level HODL Rx Level HO



TRAFFIC HO

PBGT


Figure 4A: Overview of proposed multi layer handover behavior


These are the suggested baseline parameters we recommend to start with. Further optimization can be done there after to improve your network performance.

AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5LMRG = 24 (disabled)AUCL = -47 dBm (disabled)BSC TRHO (TRHO = -85 dBm)

AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5UL Rx Level HO = -105 dBmDL Rx Level HO = -97 dBmLMRG = 3 dBQMRG = 3 dB

AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5 LMRG = 24 dB (disabled)QMRG = 3 dBPBGT = 4/6 dB

Macro GSM850AUT = 80%AML = 100%


Macro GSM1900 Macro GSM1900AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5LMRG = 24 dB (disabled)QMRG = 3 dBPBGT = 4/6 dB



AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5 LMRG = 24 dB (disabled)QMRG = 3 dB


AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5UL Rx Level HO = -105 dBmDL Rx Level HO = -97 dBmLMRG = 3 dBQMRG = 3 dB

AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5 LMRG = 24 dB (disabled)QMRG = 3 dBPBGT = 4/6 dB



Macro GSM1900 Macro GSM1900AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5LMRG = 24 dB (disabled)QMRG = 3 dBPBGT = 4/6 dB



AMR FR UL/DL RX Qual HO = 5AMR HR UL/DL RX Qual HO = 5EFR UL/DL RX Qual HO = 5 LMRG = 24 dB (disabled)QMRG = 3 dB

Figure 4B: Proposed Baseline Parameter set

FIELD GUIDE 11 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 3.1.3.1 Umbrella Ho Vs Traffic Reason HO

Umbrella handovers do not offer much flexibility. Only the RxLevelDL controls the handover from the 850 to 1900 layer. Traffic Reason handovers offer better flexibility as the load of the serving and target cell can be set plus the RxLevelDL and a margin can also be set giving the engineer more control of the layers.

UMBRELLA HO TRAFFIC HO

UMBRELLA HO is allowed only when1. Rx Level DL > Umbrella Threshold (e.g. -90 dBm)

HO even if 850 is not loaded HO only if 850 is loaded

850

1900

850

1900

BSC Controlled TRAFFIC HO is allowed only when1. Load @ 850 > AMH Upper Load Threshold (e.g. 80%)2. Load @ 1900 < AMH Max Load of Target Cell (e.g. 100%)3. Rx Level DL > TRHO Target Level (e.g. 85 dBm)4. Target is at least TRHO Margin dB better (e.g. -24 dB)

UMBRELLA HO TRAFFIC HO

UMBRELLA HO is allowed only when1. Rx Level DL > Umbrella Threshold (e.g. -90 dBm)

HO even if 850 is not loaded HO only if 850 is loaded

850

1900

850

1900

BSC Controlled TRAFFIC HO is allowed only when1. Load @ 850 > AMH Upper Load Threshold (e.g. 80%)2. Load @ 1900 < AMH Max Load of Target Cell (e.g. 100%)3. Rx Level DL > TRHO Target Level (e.g. 85 dBm)4. Target is at least TRHO Margin dB better (e.g. -24 dB)

Figure 5: Umbrella vs Traffic Reason Handover 3.1.4 Trial Results in LA

Please see section 4.1 and 4.2 in the Appendix

FIELD GUIDE 12 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 3.1.5 Handover Optimization Recommended Parameter Settings (Summary)

BSC TRAFFIC REASON HO GSM850 (HOC): ATPM = -24 dB GSM1900 (HOC): ATPM = -24 dB GSM850 to GSM850 (ADJ): TRHO = N GSM850 to GSM1900 (ADJ): TRHO = -85 dBm (or similar) GSM1900 to GSM1900 (ADJ): TRHO = N GSM1900 to GSM850 (ADJ): TRHO = N AUT (AMH Upper Load Threshold) = 80% AML (AMH Max Load of Target Cell) = 100% AUCL = -47 dBm or Umbrella HO = N HANDOVER MARGINS (ADJ) Collocated BTS (A/X,B/Y,C/Z)

GSM 850 to GSM 850 : PMRG = 6 dB LMRG = 24 dB QMRG = 3 dB GSM850 to GSM1900 : PMRG = 63 LMRG = 24 dB QMRG = 0 GSM1900 to GSM1900 : PMRG = 6 dB LMRG = 24 dB QMRG = 3 dB GSM1900 to GSM850 : PMRG = 63 LMRG = 3 dB QMRG = 3 dB Non Collocated BTS GSM 850 to GSM 850 : PMRG = 4 dB LMRG = 24 dB QMRG = 3 dB GSM850 to GSM1900 : PMRG = 63 LMRG = 24 dB QMRG = 0 GSM1900 to GSM1900 : PMRG = 4 dB LMRG = 24 dB QMRG = 3 dB GSM1900 to GSM850 : PMRG = 63 LMRG = 24 dB QMRG = 3 dB LEVEL HO (HOC) Only on Collocated BTS AND in one direction GSM 1900 to GSM 850 LUR - UL Rx Level HO = -105 dBm LUP/LUN = 1/1 LDR - DL Rx Level HO = -97 dBm LDP/LDN = 1/1 RX QUALITY HO (HOC) QDRH/QURH : 5/5 QDP/QDN = 3/4 QDRF/QURF : 5/5 QUP/QUN = 3/4 QDR/QUR : 5/5 Attached is an excel sheet for reference purposes

BSC

DB_ NAMEDB_VALUEDescriptionRemark

amh_upper_load_thld80Set the max load allowed before triggering TRHO

amh_max_load_of_tgt_cell100Set the max load allowed for a target cell in TRHO

BTS


amr_ho_fr_thr_dl_rx_qual5AMR FR downlink quality HO threshold - rx qualityAMR only. EFR value is an HOC parameter

amr_ho_fr_thr_ul_rx_qual5AMR FR uplink quality HO threshold - rx qualitypx/nx same as EFR threshold

amr_ho_hr_thr_dl_rx_qual5AMR HR downlink quality HO threshold - rx qualityAMR only. EFR value is an HOC parameter

amr_ho_hr_thr_ul_rx_qual5AMR HR uplink quality HO threshold - rx qualitypx/nx same as EFR threshold

amr_poc_hr_pc_l_thr_dl_rx_qual3AMR HR POC lower threshold downlink rx quality

amr_poc_hr_pc_l_thr_ul_rx_qual3AMR HR POC lower threshold uplink rx quality

amr_poc_hr_pc_u_thr_dl_rx_qual1AMR HR POC upper threshold downlink rx quality

amr_poc_hr_pc_u_thr_ul_rx_qual1AMR HR POC upper threshold uplink rx quality

amr_poc_fr_pc_l_thr_dl_rx_qual4AMR FR POC lower threshold downlink rx quality

amr_poc_fr_pc_l_thr_ul_rx_qual4AMR FR POC lower threshold uplink rx quality

amr_poc_fr_pc_u_thr_dl_rx_qual3AMR FR POC upper threshold downlink rx quality

amr_poc_fr_pc_u_thr_ul_rx_qual3AMR FR POC upper threshold uplink rx quality

amh_upper_load_thldAMH BTS settings will be changed by rf engineers

amh_lower_load_thldAMH BTS settings will be changed by rf engineers

amh_max_load_of_tgt_cellAMH BTS settings will be changed by rf engineers

amh_trho_guard_timeAMH BTS settings will be changed by rf engineers

HOC


min_int_ho_req4

min_int_unsucc_ho_attempt3

ho_a_l_dl_window_size6Averaging Window Size for downlink level handover

ho_a_l_dl_weighting2DL rx level DTX weighting

ho_a_l_ul_window_size6Averaging Window Size for uplink level handover

ho_a_l_ul_weighting2UL rx level DTX weighting

ho_a_q_dl_window_size1Averaging Window Size for downlink quality handover

ho_a_q_dl_weighting2DL rx quality DTX weighting

ho_a_q_ul_window_size1Averaging Window Size for uplink quality handover

ho_a_q_ul_weighting2UL rx quality DTX weighting

ho_t_l_dl_rx_level13Downlink level HO threshold - rx level-97 dBm

ho_t_l_dl_px1Downlink level HO threshold - px

ho_t_l_dl_nx1Downlink level HO threshold - nx

ho_t_l_ul_rx_level5Uplink level HO threshold - rx level-105 dBm

ho_t_l_ul_px1Uplink level HO threshold - px

ho_t_l_ul_nx1Uplink level HO threshold - nx

ho_t_q_dl_rx_qual5Downlink quality HO threshold - rx qualityEFR only. AMR value is a BTS parameter

ho_t_q_dl_px3Downlink quality HO threshold - px

ho_t_q_dl_nx4Downlink quality HO threshold - nx

ho_t_q_ul_rx_qual5Uplink quality HO threshold - rx qualityEFR only. AMR value is a BTS parameter

ho_t_q_ul_px3Uplink quality HO threshold - px

ho_t_q_ul_nx4Uplink quality HO threshold - nx

ho_t_i_dl_rx_level30Downlink interference HO threshold - rx level-80 dBm. Quality threshold is the same as downlink quality HO

ho_t_i_dl_px1Downlink interference HO threshold - px

ho_t_i_dl_nx1Downlink interference HO threshold - nx

ho_t_i_ul_rx_level20Uplink interference HO threshold - rx level-90 dBm. Quality threshold is the same as uplink quality HO

ho_t_i_ul_px1Uplink interference HO threshold - px

ho_t_i_ul_nx1Uplink interference HO threshold - nx

avg_window_size_adj_cell4Averaging Window Size for adjacent cell

ho_period_umbrella6Handover Period Umbrella

ho_period_pbgt4Handover Period PBGT

amh_trho_pbgt_margin-24TRHO PBGT Margin

POC


pc_ctrl_enabled1Changed for sanity check only

pc_incr_step_size1Changed for sanity check only

pc_red_step_size0Changed for sanity check only

pc_control_interval0Changed for sanity check only

pc_a_l_dl_window_size1Averaging Window Size for downlink level power control

pc_a_l_dl_weighting2DL rx level DTX weighting

pc_a_l_ul_window_size1Averaging Window Size for uplink level power control

pc_a_l_ul_weighting2UL rx level DTX weighting

pc_a_q_dl_window_size1Averaging Window Size for downlink quality power control

pc_a_q_dl_weighting2DL rx quality DTX weighting

pc_a_q_ul_window_size1Averaging Window Size for uplink quality power control

pc_a_q_ul_weighting2UL rx quality DTX weighting

pc_l_t_lev_dl_rx_level25Downlink level POC lower threshold - rx level-75 dBm

pc_l_t_lev_dl_px1Downlink level POC lower threshold - px

pc_l_t_lev_dl_nx1Downlink level POC lower threshold - nx

pc_u_t_lev_dl_rx_level35Downlink level POC upper threshold - rx level-85 dBm

pc_u_t_lev_dl_px1Downlink level POC upper threshold - px

pc_u_t_lev_dl_nx1Downlink level POC upper threshold - nx

pc_l_t_lev_ul_rx_level15Uplink level POC lower threshold - rx level-95 dBm

pc_l_t_lev_ul_px1Uplink level POC lower threshold - px

pc_l_t_lev_ul_nx1Uplink level POC lower threshold - nx

pc_u_t_lev_ul_rx_level25Uplink level POC upper threshold - rx level-85 dBm

pc_u_t_lev_ul_px1Uplink level POC upper threshold - px

pc_u_t_lev_ul_nx1Uplink level POC upper threshold - nx

pc_l_t_qual_dl_rx_qual3Downlink quality POC lower threshold - rx qualityEFR only. AMR value is a BTS parameter

pc_l_t_qual_dl_px1Downlink quality POC lower threshold - px

pc_l_t_qual_dl_nx1Downlink quality POC lower threshold - nx

pc_u_t_qual_dl_rx_qual1Downlink quality POC upper threshold - rx qualityEFR only. AMR value is a BTS parameter

pc_u_t_qual_dl_px1Downlink quality POC upper threshold - px

pc_u_t_qual_dl_nx1Downlink quality POC upper threshold - nx

pc_l_t_qual_ul_rx_qual3Uplink quality POC lower threshold - rx qualityEFR only. AMR value is a BTS parameter

pc_l_t_qual_ul_px1Uplink quality POC lower threshold - px

pc_l_t_qual_ul_nx1Uplink quality POC lower threshold - nx

pc_u_t_qual_ul_rx_qual1Uplink quality POC upper threshold - rx qualityEFR only. AMR value is a BTS parameter

pc_u_t_qual_ul_px1Uplink quality POC upper threshold - px

pc_u_t_qual_ul_nx1Uplink quality POC upper threshold - nx

ADJ

DB_ NAME850 to 850850 to 19001900 to 19001900 to 850DescriptionRemark

ho_priority_level3333Changed for sanity check only

ho_margin_pbgt4 / 6634 / 6636 for intra-site adjacencies, 4 otherwise

ho_margin_lev2424243 / 243 only for co-located 850 / 1900 sectors

ho_margin_qual3333

ho_level_umbrella63636363Umbrella disabled.

enable_ho_margin_l_q1111Enable use of margins in Level/Quality HO target cell evaluation

trho_target_level02500

dadlb_target_cell0000Changed for sanity check only

amr_dadlb_target_cell0000Changed for sanity check only

jledesmaParameters for MBCCH MultiBand.xls

FIELD GUIDE 13 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 3.2 AMR HR OPTIMIZATION

Optimizing the AMR HR usage results in the reduction of interference in the network. Higher HR usage would translate to better drop call rate. The DCR gain varies per BSC.

Interference Limited networks show major improvement in DCR Coverage Limited networks benefit only if there is some interference otherwise the DCR

remains the same

Big slope -> Interference limitedcluster

Flat slope -> Coverage limitedcluster

Figure 6: Increasing HR usage in an interference-limited network improves the DCR by reducing interference that could cause drop calls. Using aggressive HR significantly reduces the interference resulting in a flat slope indicating that majority of the call drops would be coverage related.

3.2.1 Recommended Parameter Settings for 70% HR Usage

Why 70%? This is a reasonable value for reducing interference, improving the drop call rate, and maintaining reasonable FER in the network.

Below is the recommended baseline parameter set for 70% HR usage:

MaxCap Feature = disabled QDP=QUP=4 QDN=QUN=6 QMRG=2 IHRF=1 IHRH=5 QDRH=QDRF=5 QURH=QURF=5 FRL/FRU=50/70 IAC=1 HRI=1


The parameter set presented here is the recommended baseline. If we want to go100% HR penetration then the FRL/FRU can be changed accordingly to 99/100 to achieve this but take note that using this setting will FER and voice quality. From this baseline we can optimize it further to balance the DCR and Voice Quality.

HR Usage Voice Quality FER Interference* Intra HO100% Worse Worse Better More

0% Better Better Worse Less/None

* interference limited network

Figure 7: Relation chart for HR Usage

3.2.2 Trial Results in LA

Below is an example of the DCR improvement with about 65% HR usage in one BSC in LA. There was a 30% improvement in the drop call rate using 60% HR usage as a target. The AMR HR codec distribution is shown in section 4.5 in the Appendix

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Baseline HR%=70% Log. (Baseline) Log. (HR%=70%)

Reference

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Baseline HR%=70% Log. (Baseline) Log. (HR%=70%)

Reference

30% improvement

Figure 8A: DCR improvement with 65% HR usage


Parameter Old Settings 60% HR Baseline

IAC 1 1 FRL 20 40 FRU 40 60 IHRF 2 1 IHRH 4 5 QDRF 5 5 QURF 5 5 QDRH 5 5 QURH 5 5 QDR No Change 6 QUR No Change 6 QDP Dependent on BTS (2, 3, 4) 4 QDN Dependent on BTS (3, 4, 6) 6 QUP Dependent on BTS (2, 3, 4) 4 QUN Dependent on BTS (3, 4, 6) 6

QMRG Dependent on BTS and adjacent

cell (-2, 2, 3, 10) 2 MaxCap OFF OFF HR Usage 23% 65%

Figure 8B: Parameter settings before and after and the resulting HR usage

3.2.3 DL FER and C/I Performance for 85% HR Usage in Detroit

Detroit used 100% HR usage settings in their market (FRL/FRU = 99/100). Below are the parameter settings for the trial and the DCR. The DL FER and C/I performance results are in sections 4.3, and 4.4 in the Appendix.

DETRBSC15

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%D-LC-BHErlangs BH

Figure 9A: DCR for Detroit BSC with 100% HR settings. This was implemented 3/22/05


Parameter Baseline 100% HR IAC 2 1 HRL 40 99 HRU 65 100 IHRF 2 1 IHRH 4 6 QDRF 5 5 QURF 5 5 QDRH 5 5 QURH 5 5 QDR 5 5 QUR 5 5 QDP 4 2 QDN 4 4 QUP 4 2 QUN 4 4 MaxCap OFF OFF HR Usage 25% 85%

Figure 9B: Parameter Settings Before and After and the resulting HR usage 3.2.4 MAXCAP Feature

The MaxCap feature was designed during the MaxCap project in Miami back in 2H of 2004. It was observed that when inter cell handover and unpacking is triggered at the same time, and there is no suitable target cell, the call remains in HR the call does not unpack.

As a result, Voice Quality of HR call may become worse and customer will experience bad speech quality.

The Max Cap feature can be activated/deactivated from CD 3.0 onwards and the default value is ON (unpacking allowed).

Note that when Max Cap feature is ON unpacking is allowed in the specific condition described above. Therefore, we expect more number of intra cell HOs (depending upon quality threshold, nx/px) and this increases the probability of dropping calls.

Currently, Nokia has recommended that the MaxCap feature be turned OFF until further improvements to the feature can be made that would benefit the customer.

Please refer to BSC Change Delivery 3.0 for S11 SW 1.34-0 issue 1.2-0 for instructions on how to deactivate the MaxCap feature.

FIELD GUIDE 17 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 4. APPENDIX : PERFORMANCE CHARTS

Below are some performance charts for the related activities

4.1 Indoor Coverage

Average Signal Strenght

-102

-100

-98

-96

-94

-92

-90

-88

-86

-84

-82

-801 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

DLUL

LSANBSC27 on Friday Feb.25th 2005

Average Signal Strength24 Hr. RSSI Profile shows 3 to 6 dB difference between 1700 BH and 2100 BH

24 Hr. Traffic Profile ICBH traffic to be high at 2100H indoor call traffic.

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Total Traffic ICBH Traffic

ENTIRE CLUSTER on Friday Feb.25th 2005

FIELD GUIDE 18 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 4.2 HO Management In A Multi BCCH Environment

BIGGER HYSTERESIS FOR HO

REMOVED LEVEL HO TRAFFIC HO replaces the UMBRELLA HOBIGGER HYSTERESIS FOR HO

REMOVED LEVEL HO TRAFFIC HO replaces the UMBRELLA HO

2 00 , 0 0 0

3 00 , 0 0 0

4 00 , 0 0 0

5 00 , 0 0 0

6 00 , 0 0 0

7 00 , 0 0 0

8 00 , 0 0 0

9 00 , 0 0 0

1 , 0 00 , 0 0 0

1 , 1 00 , 0 0 0

01.0

1.05

02.0

1.05

03.0

1.05

04.0

1.05

05.0

1.05

06.0

1.05

07.0

1.05

08.0

1.05

09.0

1.05

10.0

1.05

11.0

1.05

12.0

1.05

13.0

1.05

14.0

1.05

15.0

1.05

16.0

1.05

17.0

1.05

18.0

1.05

19.0

1.05

20.0

1.05

21.0

1.05

22.0

1.05

23.0

1.05

24.0

1.05

25.0

1.05

26.0

1.05

27.0

1.05

28.0

1.05

29.0

1.05

30.0

1.05

31.0

1.05

01.0

2.05

02.0

2.05

03.0

2.05

04.0

2.05

05.0

2.05

06.0

2.05

07.0

2.05

08.0

2.05

09.0

2.05

10.0

2.05

11.0

2.05

12.0

2.05

13.0

2.05

14.0

2.05

15.0

2.05

16.0

2.05

17.0

2.05

18.0

2.05

19.0

2.05

20.0

2.05

21.0

2.05

22.0

2.05

23.0

2.05

24.0

2.05

25.0

2.05

26.0

2.05

27.0

2.05

28.0

2.05

L S A N 03L S A N 18L S A N 27

5 0 % R E D U CTIO N in H O A TT EM P TS

2 00 , 0 0 0

3 00 , 0 0 0

4 00 , 0 0 0

5 00 , 0 0 0

6 00 , 0 0 0

7 00 , 0 0 0

8 00 , 0 0 0

9 00 , 0 0 0

1 , 0 00 , 0 0 0

1 , 1 00 , 0 0 0

01.0

1.05

02.0

1.05

03.0

1.05

04.0

1.05

05.0

1.05

06.0

1.05

07.0

1.05

08.0

1.05

09.0

1.05

10.0

1.05

11.0

1.05

12.0

1.05

13.0

1.05

14.0

1.05

15.0

1.05

16.0

1.05

17.0

1.05

18.0

1.05

19.0

1.05

20.0

1.05

21.0

1.05

22.0

1.05

23.0

1.05

24.0

1.05

25.0

1.05

26.0

1.05

27.0

1.05

28.0

1.05

29.0

1.05

30.0

1.05

31.0

1.05

01.0

2.05

02.0

2.05

03.0

2.05

04.0

2.05

05.0

2.05

06.0

2.05

07.0

2.05

08.0

2.05

09.0

2.05

10.0

2.05

11.0

2.05

12.0

2.05

13.0

2.05

14.0

2.05

15.0

2.05

16.0

2.05

17.0

2.05

18.0

2.05

19.0

2.05

20.0

2.05

21.0

2.05

22.0

2.05

23.0

2.05

24.0

2.05

25.0

2.05

26.0

2.05

27.0

2.05

28.0

2.05

L S A N 03L S A N 18L S A N 27

5 0 % R E D U CTIO N in H O A TT EM P TS

20% REDUCTIO N in DROPPED CALL DURING HO20% REDUCTIO N in DROPPED CALL DURING HO

There was almost 50% reduction in handovers in the LA market after the layers were optimized. The HO distribution is now mostly PBGT and Quality. The main impact is 20% reduction in the counts of HO related drops.

FIELD GUIDE 19 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 4.3 AMR Downlink FER and RXQUAL (Detroit)

Baseline parameter setting at 25% AMR HR usage

HR RXQUAL vs FER Distribution

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

0 4 8 12 16 20 24 28 32 36 40 44 48 60 68 72 76 64 56 84 52 80 96

76543210

100% HR settings at 85% AMR HR usage

HR RXQUAL vs FER Distribution

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

0 4 8 12 16 20 24 28 32 36 40 44 48 60 68 72 76 64 56 84 52 80 88

76543210

Improved RXQUAL distribution Improved DL FER from 89% to 91%

FIELD GUIDE 20 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 4.4 DL AMR HR C/I Distribution Curve (Detroit)

HR C/I Distribution Curve

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

C/I (dB)

BeforeAfter

There C/I distribution curve improved after HR penetration was changed from 25% to

85% There was also an improvement in the coverage as we have more samples in the 6 db

to 14 dB range

FIELD GUIDE 21 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 4.5 AMR Codec Distribution (LA Trial)

100% 95% 90% 85% 80% 75% 70% 65% 60% 55%

50%

HR CODEC DISTRIBUTION %

50%

55%

60%

65%

70%

75%

80%

85%

90%

95%

02/2

8/05

03/0

2/05

03/0

4/05

03/0

6/05

03/0

8/05

03/1

0/05

03/1

2/05

03/1

4/05

03/1

6/05

03/1

8/05

03/2

0/05

03/2

2/05

03/2

4/05

03/2

6/05

03/2

8/05

03/3

0/05

04/0

1/05

04/0

3/05

04/0

5/05

04/0

7/05

04/0

9/05

04/1

1/05

04/1

3/05

04/1

5/05

04/1

7/05

HR 7.5 HR 5.9 HR 4.75

FR CODEC DISTRIBUTION %100%

02/2

8/05

03/0

2/05

03/0

4/05

03/0

6/05

03/0

8/05

03/1

0/05

03/1

2/05

03/1

4/05

03/1

6/05

03/1

8/05

03/2

0/05

03/2

2/05

03/2

4/05

03/2

6/05

03/2

8/05

03/3

0/05

04/0

1/05

04/0

3/05

04/0

5/05

04/0

7/05

04/0

9/05

04/1

1/05

04/1

3/05

04/1

5/05

04/1

7/05

FR 12.2 FR 7.4 FR 5.9 FR 4.75

30% to 45% FR

40% to 70% HR 87% HR

4% FR

MaxCap Active

AMR HR trial

AMR HR trial

New Frequency Plan

New Frequency Plan

No change in AMR codec distribution with HR usage change from 23% to 65% Changes seen in the graphs were caused by a new frequency plan and and MaxCap

FIELD GUIDE 22 (22) DCR Reduction Strategy System Planning and Performance Engineering James Michael Ledesma 04/16/05 4.6 EFL Formula:

=

TRXTCHAvg

EFL 1Freq of #BH Erl

4.7 Example Of XY Scatter Plot for DCR vs Ave Erlang/Cell

Sample SCATTERPLOT

DCR8CTraffic/Cell

03/24/2005 161.634.09Creating the scatter plot

03/24/2005 171.674.74

03/24/2005 182.053.911You need to have two columns for the scatter plot ( DCR and Average Erlang/Cell )

03/24/2005 191.693.262It is recommended to use Hourly Data for DCR and Traffic to get more granularity

03/24/2005 201.742.783Go to INSERT, CHART, XY SCATTER

03/24/2005 211.922.774Create the chart and use the TRAFFIC and DCR for X and Y axis respectively

03/24/2005 222.252.01

03/24/2005 232.151.33

03/25/2005 001.280.97

03/25/2005 011.880.44

03/25/2005 022.920.22

03/25/2005 033.470.09

03/25/2005 041.070.08

03/25/2005 052.860.15

03/25/2005 061.630.37

03/25/2005 071.861.07

03/25/2005 081.591.93

03/25/2005 091.602.63

03/25/2005 101.593.11

03/25/2005 111.343.28

03/25/2005 121.363.62

03/25/2005 131.293.45

03/25/2005 141.623.42

03/25/2005 151.383.62

03/25/2005 161.673.70

03/25/2005 171.823.58

03/25/2005 181.413.19

03/25/2005 191.482.69

03/25/2005 201.832.27

03/25/2005 211.712.19

03/25/2005 221.711.66

03/25/2005 231.391.27

03/26/2005 001.800.75

03/26/2005 012.080.47

03/26/2005 023.010.29

03/26/2005 034.070.13

03/26/2005 041.290.08

03/26/2005 051.270.10

03/26/2005 061.590.24

03/26/2005 070.980.61

03/26/2005 081.051.30

03/26/2005 091.332.15

03/26/2005 101.432.63

03/26/2005 111.482.83

03/26/2005 121.402.83

03/26/2005 131.902.71

03/26/2005 141.432.70

03/26/2005 151.362.54

03/26/2005 161.412.67

03/26/2005 171.242.66

03/26/2005 181.392.60

03/26/2005 191.632.38

03/26/2005 201.502.16

03/26/2005 211.551.88

03/26/2005 221.451.51

03/26/2005 232.641.15

03/27/2005 001.950.80

03/27/2005 013.030.55

03/27/2005 022.340.34

03/27/2005 031.650.18

03/27/2005 041.120.11

03/27/2005 050.840.10

03/27/2005 061.330.19

03/27/2005 070.800.39

03/27/2005 081.770.92

03/27/2005 091.651.37

03/27/2005 101.431.81

03/27/2005 111.351.90

03/27/2005 121.442.01

03/27/2005 131.641.97

03/27/2005 141.671.88

03/27/2005 151.491.75

03/27/2005 161.711.81

03/27/2005 172.182.09

03/27/2005 181.912.37

03/27/2005 191.992.60

03/27/2005 201.942.32

03/27/2005 211.942.02

03/27/2005 222.061.69

03/27/2005 233.271.14

03/28/2005 002.820.75

03/28/2005 013.580.41

03/28/2005 021.530.18

03/28/2005 033.130.11

03/28/2005 042.050.12

03/28/2005 051.640.18

03/28/2005 061.510.35

03/28/2005 071.790.95

03/28/2005 081.491.65

03/28/2005 091.472.35

03/28/2005 101.572.74

03/28/2005 111.573.09

03/28/2005 121.273.18

03/28/2005 131.483.15

03/28/2005 141.593.07

03/28/2005 151.463.14

03/28/2005 161.723.47

03/28/2005 172.013.86

03/28/2005 182.163.37

03/28/2005 191.953.09

03/28/2005 202.092.90

03/28/2005 212.382.57

03/28/2005 222.402.01

03/28/2005 232.461.27

Sample SCATTERPLOT

1.63

1.67

2.05

1.69

1.74

1.92

2.25

2.15

1.28

1.88

2.92

3.47

1.07

2.86

1.63

1.86

1.59

1.6

1.59

1.34

1.36

1.29

1.62

1.38

1.67

1.82

1.41

1.48

1.83

1.71

1.71

1.39

1.8

2.08

3.01

4.07

1.29

1.27

1.59

0.98

1.05

1.33

1.43

1.48

1.4

1.9

1.43

1.36

1.41

1.24

1.39

1.63

1.5

1.55

1.45

2.64

1.95

3.03

2.34

1.65

1.12

0.84

1.33

0.8

1.77

1.65

1.43

1.35

1.44

1.64

1.67

1.49

1.71

2.18

1.91

1.99

1.94

1.94

2.06

3.27

2.82

3.58

1.53

3.13

2.05

1.64

1.51

1.79

1.49

1.47

1.57

1.57

1.27

1.48

1.59

1.46

1.72

2.01

2.16

1.95

2.09

2.38

2.4

2.46

Profile

Average Erlang/Cell

DCR8C

Sample Scatter Plot

jledesmaHow To Create ScatterPlot.xls

INTRODUCTIONWHERE DO WE START?Network Assessment Are We Coverage or InterferenCoverage Limited NetworkInterference Limited NetworkWhat Strategies Fit Which Network?

MAIN STRATEGIESHO Management In A Multi BCCH EnvironmentControl Over Shooting CellsImprove Indoor CoverageOptimize Multi layer HandoversUmbrella Ho Vs Traffic Reason HO

Trial Results in LAHandover Optimization Recommended Parameter Settings (Summary)

AMR HR OPTIMIZATIONRecommended Parameter Settings for 70% HR UsageTrial Results in LADL FER and C/I Performance for 85% HR Usage in DetroitMAXCAP Feature

APPENDIX : PERFORMANCE CHARTSIndoor CoverageHO Management In A Multi BCCH EnvironmentAMR Downlink FER and RXQUAL (Detroit)DL AMR HR C/I Distribution Curve (Detroit)AMR Codec Distribution (LA Trial)EFL Formula:Example Of XY Scatter Plot for DCR vs Ave Erlang/Cell

Documents

Drop Call Reduction Strategy 1.0