A study on the effect of handover parameters on the network performance will be done in a trial cluster (part of Cerritos) The parameter change to be implemented as an iterative process with each drive and the results to be compared to analyze the effect of the parameters

1. Mpcs la
lte ho parameters trial

2. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 2
Overview
› A study on the effect of handover parameters on the network
performance will be done in a trial cluster (part of Cerritos)
› The parameter change to be implemented as an iterative process with
each drive and the results to be compared to analyze the effect of the
parameters
› Following parameters to be changed
A3offset;
hysteresisA3;
filtercoefficientEutranRsrp;
sMeasure;
timetotriggerA3

3. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 3
Review: LTE HO
› Evaluates if one or more intra frequency cell is better than current
serving cell
› UE receives measurement configuration in RRC Connection
Reconfiguration
› No measurement list sent to UE (UE search for all 504 physical cell id
and reports the cell(s) fulfilling the event criteria).
› UE Event Trigger controlled by:
– Filtering (How much averaging is done before event evaluation)
– Offset (How much better in dB)
– Time to trigger (For how long)

4. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 4
Main Trigger Parameters
› sMeasure = 0 { -140..-44, 0 } [dBm]
Controlling if the UE is required to perform measurements.
Disabled if set to “0” (used only RSRP is the trigger)
› a3offset = 30 { -150..150 } [0.1 dB]
Offset value for EventA3, added to serving cell
› hysteresisA3 = 10 { 0..150 } [0.1 dB]
Hysteresis value for eventA3, added to neighbor cell
› timeToTriggerA3 = 40 { 0, 40, 64, 80, 100, 128, 160, 256, 320, 480, 512,
640, 1024, 1280, 2560, 5120 } [ms]
Time after Event A3 is fulfilled when UE starts to send Measurement reports
› triggerQuantityA3 = RSRP [RSRP,RSRQ]
The quantity that triggers the event
› cellIndividualOffsetEUtran
Offset value specific to a neighbor relation

5. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 5
Handover Filtering
› To avoid that the measurement reporting is triggered by fast fading, the
measurement configuration contains filter coefficient for the UE to use
› filterCoefficientEUtraRsrp = 9{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15,
17, 19 }
Filter coefficient for RSRP measurements
› filterCoefficientEUtraRsrq = 11{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17,
19 }
Filter coefficient for RSRQ measurements

6. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 6
Event A3: A neighbour cell(b) becomes offset
better than serving cell(a)

7. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 7
Drive Info
Test Parameter
Drive Details
Date Started Time Started Date Finished Time Finished
Baseline - 12/17/2010 21:15:00 12/13/2010 00:30:00
Offset1 a3offset=10 12/23/2010 21:00:00 12/23/2010 23:15:00
Offset2 a3offset=20 12/27/2010 20:30:00 12/27/2010 23:00:00
Offset3 a3offset=30 12/28/2010 23:15:00 12/28/2010 01:45:00
Hyst1 hysteresisA3=30 12/29/2010 20:00:00 12/29/2010 22:15:00
Hyst2 hysteresisA3=40 12/30/2010 20:30:00 12/30/2010 22:30:00
Hyst3 hysteresisA3=60 12/30/2010 22:30:00 12/31/2010 01:30:00
Hyst4 hysteresisA3=70 01/03/2011 20:15:00 01/03/2010 22:15:00
TTT1 timeToTriggerA3=80 01/05/2011 20:30:00 01/05/2011 22:45:00
TTT2 timeToTriggerA3=160 01/05/2011 22:45:00 01/06/2011 00:45:00
TTT3 timeToTriggerA3=320 01/12/2011 20:00:00 01/12/2011 22:30:00
FC1 filterCoefficientEUtraRsrp=7 01/12/2011 23:00:00 02/13/2011 01:00:00
FC2 filterCoefficientEUtraRsrp=5 01/13/2011 20:00:00 01/13/2011 22:30:00
FC3 filterCoefficientEUtraRsrp=13 01/13/2011 22:45:00 01/14/2011 00:45:00
FC4 filterCoefficientEUtraRsrp=11 01/14/2011 20:15:00 01/14/2011 22:30:00
SM1 sMeasure=-70 01/15/2011 19:45:00 01/15/2011 22:15:00
SM2 sMeasure=-80 01/17/2011 20:30:00 01/17/2011 22:45:00
BL2 Baseline2 01/18/2011 20:00:00 01/18/2011 22:30:00
BL3 Baseline3 01/19/2011 20:30:00 01/19/2011 23:00:00
Hyst0 hysteresisA3=20 01/20/2011 20:15:00 01/20/2011 23:15:00
Hyst5 hysteresisA3=80 01/21/2011 20:45:00 01/21/2011 23:30:00
TTT0 timeToTriggerA3=0 01/25/2011 00:30:00 01/25/2011 02:45:00
SM3 sMeasure=-90 01/25/2011 19:00:00 01/25/2011 21:15:00
Baseline Baseline 01/25/2011 21:30:00 01/26/2011 01:00:00
TTT4 timeToTrigger=640 01/26/2011 01:15:00 01/26/2011 03:00:00

8. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 8
Trial Cluster – Drive Route

9. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 9
Baseline Test Cases
MO Parameter Baseline BL2 BL3
UeMeasControl sMeasure 0 0 -80
UeMeasControl filterCoefficientEUtraRsrp 9 5 4
ReportConfigEUtraBestCell hysteresisA3 50 30 0
ReportConfigEUtraBestCell timeToTriggerA3 40 40 480
ReportConfigEUtraBestCell a3offset 0 10 40
Baseline Baseline 2 Baseline 3
Cell Availability 100% 100% 100%
Retainability (Session Failure Rate) 0% 26% 0%
Integrity DL Throughput Mean (kbps) 2636.85 2482.42 2511.49
Integrity DL Throughput Max (kbps) 3664.32 3600.96 3738.24
Mobility (Handover Success Rate) 100% 100% 100%
FTP DL session starts 14 19 14
FTP DL session ends 14 14 14
EUTRAN Intra-frequency Handover Failed events 0 0 0
EUTRAN Intra-frequency Handover (success)
events 192 322 161

10. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 10
Baseline Test Cases (contd)
› Baseline2 drive demonstrated the highest number of handovers and the
smallest delta in RSRP/RSRQ.
Handover Measurement Info (Source-to-Target)
Baseline
5.5 5.3
6.7
2.8
1.6
4.0
0
1
2
3
4
5
6
7
8
Baseline Baseline 2 Baseline 3
Average Delta RSRP(dBm) Average Delta RSRQ (dB)

11. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 11
Baseline Test Cases (contd)
› Baseline drive demonstrated the best SINR performance.
PRE-HANDOVER SINR CDF (%)
Baseline
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
SINR
Percentage
Baseline Baseline2 Baseline3

12. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 12
A3offset Test Cases
MO Parameter Baseline Offset1 Offset2 Offset3 Offset4
UeMeasControl sMeasure 0 0 0 0 0
UeMeasControl filterCoefficientEUtraRsrp 9 9 9 9 9
ReportConfigEUtraBestCell hysteresisA3 50 50 50 50 50
ReportConfigEUtraBestCell timeToTriggerA3 40 40 40 40 40
ReportConfigEUtraBestCell a3offset 0 10 20 30 40
Baseline (0) a3offset=10 a3offset=20 a3offset=30 a3offset=40
Cell Availability 100% 100% 100% 100% 100%
Retainability (Session Failure Rate) 0% 0% 0% 0% 0%
Integrity DL Throughput Mean (kbps) 2636.85 2365 2509.72 2415.835 2564.95
Integrity DL Throughput Max (kbps) 3664.32 3632 3696 3674.88 3653.76
Mobility (Handover Success Rate) 100% 100% 99.23% 100% 100%
FTP DL session starts 14 13 13 14 18
FTP DL session ends 14 13 13 13 17
EUTRAN Intra-frequency Handover
Failed events 0 0 1 0 0
EUTRAN Intra-frequency Handover
(success) events 192 161 129 118 99

13. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 13
A3offset Test Cases (contd)
› There was a clear decrease in the number of handovers and an increase in the
RSRP/RSRQ delta as went from a3offset=0 to a3offset=40.
› This is expected as the sum of hysteresisA3 and a3offset increases.
Notice, as expected, Delta RSRP ~ hysteresisA3+a3offset.
Handover Measurement Info (Source-to-Target)
a3Offset
5.5
6.6
7.4
8.2
9.0
2.8
3.4
4.2
4.9 5.2
0
2
4
6
8
10
Baseline (0) a3Offset=10 a3Offset=20 a3Offset=30 a3Offset=40
Average Delta RSRP(dBm) Average Delta RSRQ (dB)

14. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 14
A3offset Test Cases (contd)
› Baseline (smallest offset) demonstrated the best SINR performance.
PRE-HANDOVER SINR CDF (%)
a3Offset
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
SINR
Percentage
Baseline (0) a3Offset=10 a3Offset=20 a3Offset=30 a3Offset=40

15. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 15
HysteresisA3 Test Cases
MO Parameter Hyst0 Hyst1 Hyst2 Baseline Hyst3 Hyst4 Hyst5
UeMeasControl sMeasure 0 0 0 0 0 0 0
UeMeasControl filterCoefficientEUtraRsrp 9 9 9 9 9 9 9
ReportConfigEUtraBestCell hysteresisA3 20 30 40 50 60 70 80
ReportConfigEUtraBestCell timeToTriggerA3 40 40 40 40 40 40 40
ReportConfigEUtraBestCell a3offset 0 0 0 0 0 0 0
hysteresisA3=20 hysteresisA3=30 hysteresisA3=40 Baseline (50) hysteresisA3=60 hysteresisA3=70 hysteresisA3=80
Cell Availability 100% 100% 100% 100% 100% 100% 100%
Retainability (Session Failure
Rate) 19% 0% 0% 0% 0% 0% 0%
Integrity DL Throughput Mean
(kbps) 2545.26 2380.99 2418.08 2636.85 2464.73 2275.54 2548.9
Integrity DL Throughput Max
(kbps) 3706.56 3590.4 3664.32 3664.32 3442.56 3643.2 3632.64
Mobility (Handover Success
Rate) 100% 100% 100% 100% 100% 100% 100%
FTP DL session starts 16 13 14 14 13 12 14
FTP DL session ends 13 13 14 14 13 12 14
EUTRAN Intra-frequency
Handover Failed events 0 1 0 0 0 0 0
EUTRAN Intra-frequency
Handover (success) events 417 337 224 192 131 140 121

16. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 16
HysteresisA3 Test Cases (contd)
› There was a clear decrease in the number of handovers and an increase in the
RSRP/RSRQ delta as went from hysteresisA3=20 to hysteresisA3=80.
› This is expected as the sum of hysteresisA3 and a3offset increases.
Notice, as expected, Delta RSRP ~ hysteresisA3+a3offset.
Handover Measurement Info (Source-to-Target)
hysteresis
3.0
3.9
4.8
5.5
6.6
7.5
8.2
1.0
1.6
2.2
2.8
3.5
4.2
4.9
0
1
2
3
4
5
6
7
8
9
hysteresisA3=20 hysteresisA3=30 hysteresisA3=40 Baseline (50) hysteresisA3=60 hysteresisA3=70 hysteresisA3=80
Average Delta RSRP(dBm) Average Delta RSRQ (dB)

17. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 17
HysteresisA3 Test Cases (contd)
› hysteresisA3=20 (smallest hysteresis) demonstrated the best SINR
performance.
PRE-HANDOVER SINR CDF (%)
Hysteresis
0
10
20
30
40
50
60
70
80
90
100
-10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
SINR
Percentage
hysteresisA3=20 hysteresisA3=30 hysteresisA3=40 Baseline (50)
hysteresisA3=60 hysteresisA3=70 hysteresisA3=80

18. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 18
TimeToTriggerA3 Test Cases
MO Parameter TTT0 Baseline TTT1 TTT2 TTT3 TTT4
UeMeasControl sMeasure 0 0 0 0 0 0
UeMeasControl filterCoefficientEUtraRsrp 9 9 9 9 9 9
ReportConfigEUtraBestCell hysteresisA3 50 50 50 50 50 50
ReportConfigEUtraBestCell timeToTriggerA3 0 40 80 160 320 640
ReportConfigEUtraBestCell a3offset 0 0 0 0 0 0
timeToTriggerA3= 0 Baseline (40) timeToTriggerA3= 80 timeToTriggerA3= 160 timeToTriggerA3= 320 timeToTriggerA3= 640
Cell Availability 100% 100% 100% 100% 100% 100%
Retainability (Session Failure
Rate) 0% 0% 0% 0% 0% 0%
Integrity DL Throughput
Mean (kbps) 2618.28 2636.85 2487.26 2461.05 2461.72 2654.53
Integrity DL Throughput Max
(kbps) 3633.24 3664.32 3600.96 3696 3653.22 3674.88
Mobility (Handover Success
Rate) 100% 100% 100% 100% 100% 100%
FTP DL session starts 13 14 13 13 13 13
FTP DL session ends 13 14 13 13 13 13
EUTRAN Intra-frequency
Handover Failed events 0 0 0 0 0 0
EUTRAN Intra-frequency
Handover (success) events 187 192 197 186 171 120

19. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 19
TimeToTriggerA3 Test Cases (contd)
› Number of handovers decreased and RSRP/RSRQ delta increased with the
increasing timeToTrigger. This is as expected.
Handover Measurement Info (Source-to-Target)
timeToTriggerA3
5.3 5.5
5.9 6.2 6.4 6.7
2.7 2.8
3.2 3.3
3.9
4.3
0
1
2
3
4
5
6
7
8
timeToTriggerA3=0 Baseline (40) timeToTriggerA3=80 timeToTriggerA3=160 timeToTriggerA3=320 timeToTriggerA3=640
Average Delta RSRP(dBm) Average Delta RSRQ (dB)

20. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 20
TimeToTriggerA3 Test Cases (contd)
› timeToTriggerA3=0 and Baseline(40) demonstrated the best SINR
performance.
PRE-HANDOVER SINR CDF (%)
timeToTriggerA3
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
SINR
Percentage
timeToTriggerA3=0 Baseline (40) timeToTriggerA3=80
timeToTriggerA3=160 timeToTriggerA3=320 timeToTriggerA3=640

21. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 21
FilterCoefficientEutraRSRP Test Cases
MO Parameter FC0 FC2 FC1 Baseline FC4 FC3
UeMeasControl sMeasure 0 0 0 0 0 0
UeMeasControl filterCoefficientEUtraRsrp 3 5 7 9 11 13
ReportConfigEUtraBestCell hysteresisA3 50 50 50 50 50 50
ReportConfigEUtraBestCell timeToTriggerA3 40 40 40 40 40 40
ReportConfigEUtraBestCell a3offset 0 0 0 0 0 0
filterCoefficient
EUtraRsrp=3
filterCoefficient
EUtraRsrp=5
filterCoefficient
EUtraRsrp=7 Baseline (9)
filterCoefficient
EUtraRsrp=11
filterCoefficient
EUtraRsrp=13
Cell Availability 100% 100% 100% 100% 100% 100%
Retainability (Session Failure Rate) 0% 0% 0% 0% 0% 0%
Integrity DL Throughput Mean (kbps) 2661.5 2549.69 2423.83 2636.85 2553.79 2540.09
Integrity DL Throughput Max (kbps) 3706.56 3600.96 3590.4 3664.32 3706.56 3759.36
Mobility (Handover Success Rate) 100% 100% 100% 100% 99.38% 100.00%
FTP DL session starts 13 13 13 14 13 13
FTP DL session ends 13 13 13 14 13 13
EUTRAN Intra-frequency Handover
Failed events 0 0 0 0 1 0
EUTRAN Intra-frequency Handover
(success) events 269 262 214 192 161 141

22. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 22
FilterCoefficientEutraRSRP Test Cases (contd)
› Number of handovers decreased and RSRP/RSRQ delta increased with the
increasing filterCoefficientEUtraRsrp.
› This is as expected as the number of measurement samples analyzed for each
handover increases.
Handover Measurement Info (Source-to-Target)
filterCoefficientEUtraRsrp
6.0 6.0 5.8 5.5 5.5 5.4
2.0 2.2
2.6 2.8
3.8
4.4
0
1
2
3
4
5
6
7
filterCoefficientEUtraRsrp=3 filterCoefficientEUtraRsrp=5 filterCoefficientEUtraRsrp=7 Baseline (9) filterCoefficientEUtraRsrp=11 filterCoefficientEUtraRsrp=13
Average Delta RSRP(dBm) Average Delta RSRQ (dB)

23. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 23
FilterCoefficientEutraRSRP Test Cases (contd)
› Baseline gave the best SINR performance.
PRE-HANDOVER SINR CDF (%)
filterCoefficientEUtraRsrp
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
SINR
Percentage
filterCoefficientEUtraRsrp=3 filterCoefficientEUtraRsrp=5 filterCoefficientEUtraRsrp=7
Baseline(9) filterCoefficientEUtraRsrp=11 filterCoefficientEUtraRsrp=13

24. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 24
sMeasure test cases
MO Parameter Baseline SM1 SM2 SM3
UeMeasControl sMeasure 0 -70 -80 -90
UeMeasControl filterCoefficientEUtraRsrp 9 9 9 9
ReportConfigEUtraBestCell hysteresisA3 50 50 50 50
ReportConfigEUtraBestCell timeToTriggerA3 40 40 40 40
ReportConfigEUtraBestCell a3offset 0 0 0 0
Baseline (0) sMeasure=-70 sMeasure=-80 sMeasure=-90
Cell Availability 100% 100% 100% 100%
Retainability (Session Failure Rate) 0% 0% 0% 0%
Integrity DL Throughput Mean (kbps) 2636.85 2251.63 2496.11 2603.72
Integrity DL Throughput Max (kbps) 3664.32 3812.16 3643.2 3590.4
Mobility (Handover Success Rate) 100% 100% 100% 99.5%
FTP DL session starts 14 14 13 13
FTP DL session ends 14 14 13 13
EUTRAN Intra-frequency Handover Failed events 0 0 0 1
EUTRAN Intra-frequency Handover (success) events 192 188 204 193

25. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 25
sMeasure test cases (contd)
› No apparent trend was observed between these drives.
Handover Measurement Info (Source-to-Target)
sMeasure
5.5 5.7 5.9 5.8
2.8
3.3 3.2 3.1
0
1
2
3
4
5
6
7
Baseline (0) sMeasure=-70 sMeasure=-80 sMeasure=-90
Average Delta RSRP(dBm) Average Delta RSRQ (dB)

26. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 26
sMeasure test cases (contd)
› The effect of sMeasure parameter on the network is inconclusive in regards to
the performed drives.
PRE-HANDOVER SINR CDF (%)
sMeasure
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
SINR
Percentage
Baseline (0) sMeasure=-70 sMeasure=-80 sMeasure=-90

27. Harshit Chuttani | © Ericsson AB 2011 | 2011-01-26 | Page 27
Summary
› Tested parameters for the most part resulted in the expected behavior:
– Number of Handover events.
– RSRP/RSRQ delta upon Handover.
– Pre-handover SINR performance.
› Part of the unexpected behavior can be attributed to the variation in
drive test setup between some of the drives.
› The effect of sMeasure parameter on the network is inconclusive at this
point. It will be further analyzed during the testing on DAS nodes.
› Current Baseline is pretty suitable to the network at this early stage of
operation. It is recommended that optimization, when performed, be
performed on a case by case basis.