Optimized Power Control1

Database Features Database Features Optimized Power Control Second Assignment Optimized RxQual Handovers Channel Priority Adaptive Handovers Neighbor Cell Process Frequency Hopping Enhancements SDCCH Handovers Concentric Cells Advance Congestion Relief Call Queuing

Optimized Power ControlOptimized Power Control

Important Parameters

•dyn_step_adj (enables/disable)

•dyn_step_adj_fmpr (set the value of aggressiveness)

•step size for the UL and DL ( independent settings for UL and DL)

•power control interval and acknowledge (ms/bts)

POWER CNTRL DL

-65

-80 -80

-65

OPTIMIZED POWER CNTRL DL


Power Decrement Step Size

DL

Upper Threshold

Lower Threshold

Aggressiveness Factor

Average Power Steps

2 -65 -80 3 -50 6,4,2..

2 -65 -80 5 -50 8,4,2..

2 -65 -80 8 -50 12,4,2..

2 -65 -80 10 -50 16,2..

•Increase due to poor quality

•Increase due to low level

•Reduction due to good quality

•Oscillation prevention ( in the example above power reduction will be applied until the level is –76 dBm)


Benmore % DL Handovers

1.00

6.00

11.00

16.00

21.00

26.00

2000-0

2-1

0

2000-0

2-1

1

2000-0

2-1

2

2000-0

2-1

3

2000-0

2-1

4

2000-0

2-1

7

2000-0

2-1

8

2000-0

2-1

9

2000-0

2-2

0

2000-0

2-2

1

2000-0

2-2

4

2000-0

2-2

5

2000-0

2-2

6

2000-0

2-2

7

2000-0

2-2

8

2000-0

3-0

2

2000-0

3-0

3

2000-0

3-0

4

2000-0

3-0

5

2000-0

3-0

6

Dates

%

Benmore-3 DL HO Benmore-2 DL HO Benmore-1 DL HO

Optimized Power ControlOptimized Power ControlBenmore % Ul Handovers

2.00

7.00

12.00

17.00

22.00

27.00

32.00

37.00

2000-0

2-1

0

2000-0

2-1

1

2000-0

2-1

2

2000-0

2-1

3

2000-0

2-1

4

2000-0

2-1

7

2000-0

2-1

8

2000-0

2-1

9

2000-0

2-2

0

2000-0

2-2

1

2000-0

2-2

4

2000-0

2-2

5

2000-0

2-2

6

2000-0

2-2

7

2000-0

2-2

8

2000-0

3-0

2

2000-0

3-0

3

2000-0

3-0

4

2000-0

3-0

5

2000-0

3-0

6

Dates

%

Benmore-3 UL HO Benmore-2 UL HO Benmore-1 UL HO Poly. (Benmore-3 UL HO) Poly. (Benmore-2 UL HO) Poly. (Benmore-1 UL HO)


Benmore DCR

0.00

0.50

1.00

1.50

2.00

2.50

2000

-02-

10

2000

-02-

11

2000

-02-

12

2000

-02-

13

2000

-02-

14

2000

-02-

17

2000

-02-

18

2000

-02-

19

2000

-02-

20

2000

-02-

21

2000

-02-

24

2000

-02-

25

2000

-02-

26

2000

-02-

27

2000

-02-

28

2000

-03-

02

2000

-03-

03

2000

-03-

04

2000

-03-

05

2000

-03-

06

Dates

%

Benmore-3 DCR Benmore-2 DCR Benmore-1 Poly. (Benmore-1) Poly. (Benmore-2 DCR) Poly. (Benmore-3 DCR)

Second AssignmentSecond Assignment

Assignment Command

Assignment Command

Assignment Failure

Assignment Failure

BTS

MS

•second_assignment _attempts

•second_assignment _success

•mean holding time of sdcch

•tch assignment success rate

Second AssignmentSecond AssignmentRS04

0

1000

2000

3000

4000

5000

6000

Dates

Nu

mb

er

84.00

85.00

86.00

87.00

88.00

89.00

90.00

91.00

92.00

93.00

%

Sec Assign Atmpt Sec Assign Suc Call Setup Suc

Congestion ReliefCongestion ReliefType 1

CELL

Queue Call Handed Out

•Queue length

•Queuing time

•Handover margin

•Bounce protection

•Sufficient overlap

Congestion ReliefCongestion Relief

Typical Values– 0 < ho_margin < 15 depending on the overlap– 0 < q_length < 10– 0 < q_time < 5 sec– Bounce protect time should be set approx 0.75*MHT of call– 3 < bounce_protect_margin < 5

Stats – TCH_CONGESTION– ALLOC_TCH_FAIL– DROP CALL RATE– HANDOVER FAILURE RATE– HANDOVERS DUE CONGESTION


Type 2


Parameters– Ho_exist_congest = 2– 75% < Tch_cong_prevent_thres < 95 %– Bounce_protect_tmr– Bounce_protect_margin– Rtry_cand_prd– Congest_at_source

Stats– Same stats as type 1


Handover_required_reject_switch (set to 1)– Target BSC will be marked if handover is rejected

Number of preferred cells (set to 1)– Target Cells will be marked if handover is rejected


Congestion Relief on Mmabatho Sector 3

0

5

10

15

20

25

Dates

TC

H C

on

ge

sti

on

0

10

20

30

40

50

60

70

80

90

%

HO

Co

ng

es

tio

n

TCH Congestion [%] % Handover on Congestion

Call QueuingCall Queuing

CELL

Queue

•Queue Length

•Time in the Queue

•TCH set_up congestion

•Calls queued (mean)

•SDCCH mean holding time

Call QueuingCall Queuing

Lenasia Sector -3

0

1

2

3

4

5

6

7

8

Dates

Q-L

en

gth

0

2

4

6

8

10

12

14

16

18

20

% o

f T

CH

Se

t-U

p C

on

ge

sti

on

tch_q_length_max TCH Setup Congestion Rate[%]

Channel PriorityChannel Priority

Allows the operator to specify the relative priority the carrier

Benefits– Improves call setup– Improves the handover success rate

Trial Results ( 9 BSCs)– There was no different in the call setup or handover success rate

Reasons for Poor Results– Carriers are assign on the IOI stats and then on the priority

therefore the IOI stats overrides the priority of the RTF

Adaptive HandoversAdaptive Handovers

Triggers handover to occur faster when the conditions are deteriorating rapidly and slower when conditions are marginally poor thereby helping to prevent needless handovers

Same trigger values applies for all neighbors There are three type of adaptive handovers

– Power budgets– Quality both uplink and downlink– Level both uplink and downlink

Independent quality thresholds can be set for hopping and non-hopping carriers

Adaptive Handovers PBGTAdaptive Handovers PBGTSTART

PBGT(n) > HO_margin

Cumulative_value = cumulative_value + (PBGT(n) – HO_margin)

Cumulative_value > PBGT_trigger

Generate Handover

NO

NO

Adaptive Handovers QualAdaptive Handovers QualSTART

rxqual > l_rxqual_h

Cumulative_value = cumulative_value + (rxqual – l_rxqual_h)

Cumulative_value > qual_trigger

Generate Handover

NO

NO

Adaptive Handovers LevelAdaptive Handovers LevelSTART

rxlev <l_rxlev_h

Cumulative_value = cumulative_value + (rxlev_h – rxlev)

Cumulative_value > rxlev_trigger

Generate Handover

NO

NO

Adaptive Handovers BenefitsAdaptive Handovers Benefits

Reduction in RF Loss Rate Reduction in Drop Call Rate Reduction in Handover Failures Increase in traffic in micro cells Increase in the number of handovers

Concentric CellsConcentric Cells

Based on quality and power levels Outer zone provides coverage Inner zone provides capacity and aggressive reuse Power and Interference base algorithm

Concentric Cells Power Base AlgorithmConcentric Cells Power Base Algorithm

Carriers have reduced uplink and downlink transmit levels Intracell handover (inter zone) is performed base on the following

criteria– Both the uplink and downlink power levels are considered before a

handover can be initiated to the inner zone– Handover to outer zone is triggered if either the downlink or uplink levels

is below the respective threshold and further increase in power is not allowed


Important Parameter– rxlev_dl_zone, rxlev_ul_zone, zone_ho_hyst

Use CTP to determined values– Tarffic spread using level, quality and timing advance– To set the power level for the inner zone i.e distribution of quality versus

level Monitor Usage of Zones

– Tch_usage_inner_zone– Tch_cong_inner_zone– Zone_change_attempts– Zone_change_suc


Expected Results– Improvement in the quality by reducing the power – Decrease in RF Losses– Increase the number of handover (intracell)– Increase in TCH assignment

RxAccess Level MinRxAccess Level Min

Reasons for Testing– There are three values used –102, -108, -110 for all cells in the network– Other Motorola have different values depending on the location of cells

Benefits– Reduce the call attempts at extremely low levels thereby improving

SDCCH and TCH setup Methods

– Use CTP to check the percentage MS reports low levels at low TA– Only deploy in Urban area where penetration is high– Rural areas should be set –110 dBm– Values for indoor cells should be carefully chosen

RxQual Handover OptimizedRxQual Handover Optimized

Reasons for optimizing– New thresholds for hopping– Worst neighbor– Handover only at max power– Approximately 35 % of all handovers are quality based– Variety of settings for averaging and thresholds


Example of Results after Audit on OMC1

Number of Cells dlrxqualhoallowed l_rxqual_dl_h 2 1 20010 1 2665 0 340

176 1 3403 1 35011 1 4201 1 44013 1 45061 0 5506 1 5501 0 700


Example of Results after Audit on OMC1

Number of Cells qual_margin_flag hreqave hreqt adj_qual_margin 1 0 1 3 013 0 2 2 038 0 4 1 01 1 2 6 533 1 4 1 415 1 4 1 519 1 4 6 5559 1 5 1 464 1 5 1 15


Initial Standard Settings– Hreqave = 4– Hreqt = 1– Qual Margin = 0– Non Hopping Threshold = 340 (2*4 and 2*5)– Hopping Threshold = 453 (4*5)


Results from Initial Settings– High Internal and External Handover Congestion due

large number of handovers– Handover Congestion = Request - Attempts– Results in increase in the number of calls dropped


Proposed Settings for Macro Cells– Hreqave = 4– Hreqt = 1– Qual Margin = 0– Non Hopping Threshold = 650– Hopping Threshold = 700 – Power Flag Enabled


Proposed Settings for Micro Cells– Hreqave = 4– Hreqt = 1– Qual Margin = 0– Non Hopping Threshold = 300– Hopping Threshold = 300– Power Flag disabled


Evaluation of Results– % UL and DL Handovers– Qual Distribution using CTP– Number of Handovers– Internal and External Handover Congestion


Additional Testing– Thresholds needs to be adjusted after download of a

frequency plan i.e. as the fractional loading increase the thresholds needs to relaxed

– Investigate the use of adaptive handover instead of relaxing the thresholds

Optimized Power Control1

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