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Transcript of RF Power Control
8/3/2019 RF Power Control
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RF Power Control
August 2001
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RF Power Control
What is RF Power Control?
Why we need RF Power Control?
Execution of RF Power Control
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Power Control - Definition
Increasing or Decrease the RF power based
on the Rxlev , quality .
– Uplink ( mandatory ).
– Downlink (optional).
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RF Power Control - Affect
Uplink
– Battery Saving.
– Co-Channel Interference.
Downlink
– Co-Channel Interference.
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RF Power Control - Execution
Power Control Procedure.
Optimized Power Control.
Rapid Power Down.
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RF Power Control - Process
Process for PC for either the Rxlev,
quality
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RF Power Control – MR
MS send SACCH message every 480 ms. It contains
measuring about
– Downlink Received Signal Strength.
– Downlink Received Qual.
– Neighbors BCCH/BSIC with Rx Lev.
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RF Power Control – MR (cont)
The Radio Interface forward measurements about the
uplink to the HDPC .
– Uplink Signal Strength.
– Uplink Received BER.
– Uplink Interference on Idle.
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RF Power Control - Averaging
We can’t depend on just one SACCH message MR, so we
make an algorithm for averaging .
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RF Power Control - Averaging
The Averaging/Voting algorithms are based on four
parameters
– HREQAVE
– HREQT
– N
– P
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RF Power Control - Triggering
If P out of N exceed the threshold a decision will take
place
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RF Power Control – Process summery
Decision was taken due to level .
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RF Power Control – Process summery
Decision was taken due to quality.
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RF Power Control - Decision
Decision_alg_number = 1INCREASE
Check Oscillation before
There is no such a thing
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Optimization RF Power Control
GSR3 GSR4
SINGLE power increase /
decrease step size for UL &
DL
Separate for UL & DL
Power increase step size :
range of 2 - 6 db Power increase step size : range
of 2 - 14 db
Step sizes FIXED in
database Step sizes DYNAMICALLY
SET depd on current power
level NO DL power level
oscillation prevention
control
DL oscillation prevention
included
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Optimization RF PC – Step Size
SEPARATE increment/decrement step sizes for
uplink and down link
pow_inc_step_size_ulpow_inc_step_size_dl
pow_inc_step_size
pow_red_step_size_ul
pow_red_step_size_dl pow_red_step_size
2,4,6,8,10
,12,14 dB
2, 4dB
* The increment step size must be >= the decrement step size
GSR3
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Optimization RF Power Control
GSR3 GSR4
SINGLE power increase /
decrease step size for UL &
DL
Separate for UL & DL
Power increase step size :
range of 2 - 6 db Power increase step size : range
of 2 - 14 db
Step sizes FIXED in
database Step sizes DYNAMICALLY
SET depd on current power
level NO DL power level
oscillation prevention
control
DL oscillation prevention
included
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Optimization RF Power Control
GSR3 GSR4
SINGLE power increase /
decrease step size for UL &
DL
Separate for UL & DL
Power increase step size :
range of 2 - 6 db Power increase step size : range
of 2 - 14 db
Step sizes FIXED in
database Step sizes DYNAMICALLY
SET depd on current power
level NO DL power level
oscillation prevention
control
DL oscillation prevention
included
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Optimization RF PC – Dynamic step size
To ENABLE, set dyn_step_adj = 1 3 types of dynamic step size adjustments
Dynamic power stepsize increase due to poorRXQUAL
Dynamic power stepsize increase due to poorRXLEV
Dynamic power stepsize reduction due to goodRXQUAL
* NO Dynamic power stepsize reduction due to good RXLEV
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Optimization RF PC – Dynamic step size(increase due poor Rxqual)
occurs when rxqual falls below the lower rxqualthreshold
l_rxqual_ul/dl_pstepsize = DYN_POW_INC_XX_Q =
MAX [ pow_inc_step_size_xx , fhigh ( Y ) ]
where Y = l_rxlev_xx_p + pow_inc_step_size_xx -
current_rxlev_xx
where fhigh( ) denotes the rounding up of a value to thenearest multiple of 2 dB
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Optimization RF PC – Dynamic step size(Increase due to Rxqual)
l_rxlev_ul_p
u_rxlev_ul_p
Power level
pow_inc_step_size_ul
Dynamic
step size
current_rxlev_ul
Current power level
Standard stepsize
• Y = l_rxlev_xx_p + pow_inc_step_size_xx - current_rxlev_xx
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Optimization RF PC – Dynamic step size
(Increase due to Rxlev)
occurs when Rxlev falls below the lower rxlevthreshold
l_rxlev_ul/dl_pstepsize = DYN_POW_INC_XX_L = fhigh ( Y )
where Y = l_rxlev_xx_p + pow_inc_step_size_xx - current_rxlev_xx
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Optimization RF PC – Dynamic step size(Reduction due good Rxqual)
occurs when rxqual is above the upper Rxqualthreshold
u_rxqual_ul/dl_pstepsize = DYN_POW_RED_XX =
MAX [ pow_red_step_size_xx , f low ( Y ) ]
where Y = (dyn_step_adj_fmpr /10 ) * (current_rxlev_xx -
u_rxlev_xx_p)
• dyn_step_adj_fmpr = 0 to 10 ( used to control therapidity )
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Optimized RF Power Control
GSR3 GSR4
SINGLE power increase /
decrease step size for UL &
DL
Separate for UL & DL
Power increase step size :
range of 2 - 6 db Power increase step size : range
of 2 - 14 db
Step sizes FIXED in
database Step sizes DYNAMICALLY
SET depd on current power
level NO DL power level
oscillation prevention
control
DL oscillation prevention
included
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Optimized RF PC – Uplink Oscillation prevention
Problem definition
– Decrease due to good Rxqual , Increase due to
poor Rxlev
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Optimized RF PC – Uplink Oscillation prevention
Solution
– Adjust increment step size ( via HDPC)
– Ignore decrease due to Rxqual after increasedue to Rxlev ( mspwr_alg =1 )
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Optimized RF PC – Downlink Oscillation
prevention
Decrease due to good Rxqual followed by
Increase due poor Rxlev immediately
current_rxlev_dl < l_rxlev_dl_p + pow_red_step_size_dl+ 2dB If the following condition is true, an
RXQUAL based power reduction will NOT
be performed:
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Optimized RF PC – Downlink Oscillation
prevention
current_rxlev_dl < l_rxlev_dl_p +pow_red_step_size_dl + 2dB
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RF Rapid Power Down
Where ?
– In urban area .
Problem
– Low step size
– Slow change
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RF Rapid Power control - Rapid down
Definition – MS power is reduced faster
than the standard ramp down
time
– Takes precedence over
conventional PC
Benefits – Reduced UL interference
– Reduced MS TX power Fast Power Down OFF
Fast Power Down ON
MS Tx Power
Uplink RxLev rpd_trigger
rpd_offset
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Interaction between RPD and PC
Averaging & voting of normal PC is not utilised
No voting employed: hreqt, n, p assumed as 1
Hreqave value equal to rpd_period
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RF Power Control
Thank You
Q & A