optimized power control1
DESCRIPTION
Power ControlTRANSCRIPT
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
Optimized Power ControlOptimized Power Control
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)
Optimized Power ControlOptimized Power Control
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)
Optimized Power ControlOptimized Power Control
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
Congestion ReliefCongestion Relief
Type 2
Congestion ReliefCongestion Relief
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
Congestion ReliefCongestion Relief
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 ReliefCongestion Relief
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
Concentric Cells Power Base AlgorithmConcentric Cells Power Base Algorithm
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
Concentric Cells Power Base AlgorithmConcentric Cells Power Base Algorithm
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
RxQual Handover OptimizedRxQual Handover Optimized
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
RxQual Handover OptimizedRxQual Handover Optimized
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
RxQual Handover OptimizedRxQual Handover Optimized
Initial Standard Settings– Hreqave = 4– Hreqt = 1– Qual Margin = 0– Non Hopping Threshold = 340 (2*4 and 2*5)– Hopping Threshold = 453 (4*5)
RxQual Handover OptimizedRxQual Handover Optimized
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
RxQual Handover OptimizedRxQual Handover Optimized
Proposed Settings for Macro Cells– Hreqave = 4– Hreqt = 1– Qual Margin = 0– Non Hopping Threshold = 650– Hopping Threshold = 700 – Power Flag Enabled
RxQual Handover OptimizedRxQual Handover Optimized
Proposed Settings for Micro Cells– Hreqave = 4– Hreqt = 1– Qual Margin = 0– Non Hopping Threshold = 300– Hopping Threshold = 300– Power Flag disabled
RxQual Handover OptimizedRxQual Handover Optimized
Evaluation of Results– % UL and DL Handovers– Qual Distribution using CTP– Number of Handovers– Internal and External Handover Congestion
RxQual Handover OptimizedRxQual Handover Optimized
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