WS Prague Power Control

8/10/2019 WS Prague Power Control

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RADIOMOBIL WORKSHOP

Power Control Process

April 1014, 2000

Prague


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CUSTOMER SUPPORT SERVICES DIVISION

Network Operations Engineering2April 2000

Overview


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Effect of Power Control

Power Co nt ro l Box

0

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

1 5 91

3

1

7

2

1

2

5

2

9

3

3

3

7

4

1

4

5

4

9

5

3

5

7

6

1

6

5

6

9

7

3

7

7

8

1

8

5

8

9

9

3

9

7

1

0

1

1

0

5

R X L E V

M

R

ul_ rxle v ul_ rxlev_ PC

effective reduction in power

due to powe r contro l

P owe r B ox

Power Box

Effective reduction

in power due to PC


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MS / BSS Power Control

UL & DL Measu rements Taken

Averages Produced

A Number of Averages Compared Against Threshold

Thresho ld Exceeded

Power Output Adjusted


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Power Control due to Level

MS & BTS power control shares the same averagingresult


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Power Control due to Quality

MS & BTS power control shares the same averagingresult


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Standard Power Control

decision_alg_num = 0 bts_p_con_ack and ms_p_con_ack timers are not used.

decision_alg_num = 1

bts_p_con_ack and ms_p_con_ack timers are used.

Quality takes precedence!

RxQual >l_rxqual_ul_h

&

RxLev > u_rxlev_ul_p

Decisio n_alg_number = 1INCREASE


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Power Control Parameters (1)

Tim ing ...

p_con_interval p_con_interval

Command Acknow ledged Command Not Acknow ledged

decision _alg_number = 0


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Power Control Parameters (2)

Tim ing ...

p_con_interval p_con_intervalp_con_ack

Command Acknow ledged Command Not Acknow ledged

decision _alg_number = 1


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Rapid Power Down

Functionality MS power is reduced faster

than the standard ramp downtime

Takes precedence over

conventional PC

Benefits Reduced UL interference

Reduced MS TX power Fast Power Down OFFFast Power Down ON

MS Tx Power

Up link 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, passumed as 1

Hreqavevalue equal to rpd_period

Ms_p_con_intervaltimer will be overridden if

l_rxlev_ul_por l_rxqual_ul_pexceeded

Recovery from a condition where RPD took the

MS to a low level or into poor quality


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Configuration of Rapid Power Down

Configuration rapid_pwr_down

0 - OFF

1 - ON rpd_period

1 - 32 SACCH periods

rpd_trigger

0 - 63

rpd_offset 0 - 63

Algorithm

rpd_trigger

rpd_offset

l_rxlev_ul_p

u_rxlev_ul_p

Required level

ul_rxlev

63

0

Ordered power = current power + (ul_rxlevrpd_trigger + rpd_offset)/2


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Implementation Results

Micro cell PC window l_rxlev_ul_p = 25

u_rxlev_ul_p = 35

+3 dB above PC window Rpd_period = 2

Rpd_offset = 8

Rpd_trigger = 38

+6 dB above PC window

Rpd_period = 2

Rpd_offset = 11

Rpd_trigger = 41


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Radio Link Revival

The full_pwr_rflossfield enables or disables theability of the RSS to instruct the MS and BSS to use

maximum power when loss od radio resource is

detected.

Triggered when link_failcounter reaches the threshold

of link_about to_fail.

link_about_to_fail

BTS&MS full power

link_fail


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POWER CONTROL OPTIMISATION

Upl ink RxLev

l_rxlev_ul_p = 20-90

dBm

Downl ink

RxLev

hreqave = 2

hreqt = 2

Upl ink RxQual

l_rxq ual_u l_p = 1143

Downl ink

RxQual

hreqave = 2 ; hreqt = 2

l_rxqu al_ul_p_hopp ing = 4505

u_rxlev_ul_p = 30

-80

dBm

l_rxlev_dl_p = 25-85

dBm

hreqave = 2

hreqt = 2

u_rxlev_dl_p = 35

-75

dBm

u_rxq ual_ul_p = 40

1

l_rxq ual_d l_p = 1143

l_rxqu al_dl_p_hopp ing = 4505

u_rxq ual_dl_p = 40

1

n1 = 1

p1 = 1

n2 = 2

p2 = 2

n3 = 1

p3 = 1

n4 = 2

p4 = 2

6

6

2

2


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Standard Power Control

RxQual >l_rxqual_ul_h

&

RxLev > u_rxlev_ul_p

Decision_alg_number = 1

Tx Power

Cell A Cell B

qual_pw r_f lag =

1


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Medidas de DL & UL

Producc ion de muestras promediadas

Muestras prom ediadas son com paradas con umbral

Se excede el um bral

Ajuste de la po tencia de sal ida

-110 dBm

-100 dBm

-90 dBm

-80 dBm

-70 dBm

0

10

20

30

40

l_rxlev_dl_p=25

u_rxlev_dl_p=35

-85 dBm

-75 dBm


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Handover Workshop 01

Power Control(including handover thresholds)

RXQUAL POWER

CTLS

14 (0.14=BAND 0

1810 (18.10%) =BAND 77

4

1

3

5

6

2

2

8

113

5

7

45

3

226

905

0

BAND ASSUMED BER

u_rxqual_ul_p

l_rxqual_ul_

p

l_rxqual_ul_p_hopping

l_rxqual_ul_h_hopping

l_rxqual_ul_h

RXLEV POWER CTLS

-110

-47

-60

-70

-80

-90

-

100

6

3

0

10

20

30

50

4

0

-5060

RXLE

V

dBm

u_rxlev_ul_p

l_rxlev_ul_p

l_rxlev_ul_h_hopping

l_rxlev_ul_p_hopping

l_rxlev_ul_h_

rpd__trigger

Rpd_offset


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Handover Workshop 01

Power Control(including handover thresholds)

RXQUAL POWER

CTLS

14 (0.14=BAND 0

1810 (18.10%) =BAND 77

4

1

3

5

6

2

2

8

113

5

7

45

3

226

905

0

BAND ASSUMED BER

u_rxqual_ul_p

l_rxqual_ul_

p

l_rxqual_ul_p_hopping

l_rxqual_ul_h_hopping

l_rxqual_ul_h

RXLEV POWER CTLS

-110

-47

-60

-70

-80

-90

-

100

6

3

0

10

20

30

50

4

0

-5060

RXLE

V

dBm

u_rxlev_ul_p

l_rxlev_ul_p

l_rxlev_ul_h_hopping

l_rxlev_ul_p_hopping

l_rxlev_ul_h_

rpd__trigger

Rpd_offset


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Power Control Adjustment

Mobile usingless power

Also resultinggoodperformancein RF Loss

Rate

Before

After

Modified N &

P settings will

help the

effectiveness of

power control


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Recommended N & P Settings


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Funktion

BTS- und MS-Leistung werden laufend so nachgeregelt, dasowohl XX_RxLevund XX_RxQualinnerhalb einesdefinierten Fensters liegen.

Die Steuerung erfolgt durch laufende Messungen vonXX_RxLevund XX_RxQual(Measurement Reports)

Liegen die aktuellen Werte fr XX_RxLevund/oderXX_RxQual auerhalb des Fensters, so wird die BTS/MS-Leistung in Schritten von +6dB erhht

bzw von2dBm reduziert.

Zweck

In Summe weniger Leistungs-abgabe von BTS und MS

Es wird schlechter RxQual

entgegengewirkt

Power Control

-47dBmXX_Rx_Lev

63

0 -110dBm

l_rxlev_XX_p -90dBm

u_rxlev_XX_p -80dBm

P

O

W

E

R

W

I

N

D

O

W

0XX_Rx_Qual

0

7 1810

l_rxqual_XX_p 400

u_rxqual_XX_p 0

Q

U

A

L

W

I

N

D

O

W


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Power Control

Dynamische Power Control

Bisher (vor GSR4) mit pow_inc_sep_size_XX (+6dB)undpow_red_sep_size_XX(-2dB) nur statische

Abstufungen der Leistungsregelung.

Ab GSR4 dynamische Power Increase/DecreaseSchritte mglich.

Je weiter die aktuellen XX_RxLex und/oderXX_RxQual Werte auerhalb des definierten Fenstersliegen umso grere Power Increase/Decrease Schrittewerden zur Leistungsregelung angewandt.


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OPTIMISED POWER CONTROL


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Optimised Power Control - Feature Overview

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 powerlevel

NO DL power level

oscillation prevention

control

DL oscillation prevention

included


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SEPARATE increment/decrement step sizes for

uplink and down link

Optimised Power Control -Separate uplink & downlink step sizes

pow_inc_step_size_ulpow_inc_step_size_dl

pow_inc_step_size

pow_red_step_size_ul

pow_red_step_size_dlpow_red_step_size

2,4,6,8,10

,12,14 dB

2,4dB

* The increment step size must be >= the decrement step size


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IF ENABLED , increment / decrement stepsize can be changed dynamically based on:

current power levelsproximity to upper / lower power thresholds

To ENABLE, set per cell elementdyn_step_adj to1:

chg_element dyn_step_adj 1 10 cell_number=0 01 0 1 1 1

Optimised Power Control -Dynamic Stepsize

RAPID_POWER_DOWN feature can workwith Optimised Power

Control at the same time.

When rapid power trigger point is reached, the feature

OVERRIDES any Optimised Power Control dynamic adjustment

decision


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3 types of dynamic step size adjustments

Dynamic power stepsize increase due to poorRXQUAL

Dynamic power stepsize increase due to poorRXLEV

Dynamic power stepsizereduction due to goodRXQUAL

Optimised Power Control -Dynamic stepsize

*NO Dynamic powerstepsize reduction due to good RXLEV


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Dynamic power increase due to poor RXQUAL

occurs when rxqual falls below the lower rxqual

threshold

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 the

nearest multiple of 2 dB


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Dynamic power increase due to poor RXQUAL

If current power is below lower power threshold, dynamicstepsize will increase power to a standard step size abovethe lower power threshold. Otherwise dynamic stepsize willbe by the standard step size.

EG. If poor rxqual AND power level is below lower powerthreshold...

l_rxlev_ul_p

u_rxlev_ul_pPower level

pow_inc_step_size_ul

Dynamicstep size

current_rxlev_ul

Current power level

Standard stepsize


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Dynamic power increase due to poor RXLEV

occurs when rxlevfalls below the lower rxlev threshold

l_rxlev_ul/dl_p

stepsize= DYN_POW_INC_XX_L = fhigh ( Y)

where Y = l_rxlev_xx_p + pow_inc_step_size_xx - current_rxlev_xx

A dynamic power increase stepsize due to low level will

bring the power up to a standard step size above the

lower threshold of the power box


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CUSTOMER SUPPORT SERVICES DIVISIONNetwork Operations Engineering

32April 2000

Dynamic power reduction due to good RXQUAL

occurs when rxqual is above the upper rxqual

threshold

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)

where f low( ) denotes the rounding down of a value to the

nearest multiple of 2 dB


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33April 2000


where valid range for dyn_step_adj_fmpr is 0

- 10

chg_element dyn_step_adj_fmpr 10 1cell_number=0 0 1 0 1 1 1

The rateof power reduction bringing power

back to the top of the power box isproportional to dyn_step_adj_fmpr(with a

minimum required reduction of

pow_red_step_size_xx)


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34April 2000


EG. If good rxqual AND current power level isabove the upper threshold AND dyn_step_adj_fmpris 10.

l_rxlev_ul_p

u_rxlev_ul_p

Power level

Dynamic

step size

current_rxlev_ul

Current power level


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35April 2000

BTS power downlink ocillations

Defined as a rxqual based power reductionresulting in an immediate rxlev based powerincrease

If the following condition is true, an RXQUALbased power reduction will NOT beperformed:

current_rxlev_dl < l_rxlev_dl_p + pow_red_step_size_dl

+ 2dB

Note: We currently have a different algorithm whichhandles this for uplink power oscillation.


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36April 2000

BTS power downlink ocillations

l_rxlev_dl_p

u_rxlev_dl_p

pow_red_step_size_dl

Is current_rxlev_dl

less than this level??

Standard stepsize

Power level

2dB


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37April 2000

Optimised Power Control

Separate Increment and Decrement steps for ULand DL

Range of values for Power Increment Stepextendedpow_inc_step_size_ul = 2, 4, 6, , 14

dBpow_red_step_size_ul = 2, 4 dB

MSpow_inc_step_size_dl = 2, 4, 6, , 14

dBpow_red_step_size_dl = 2, 4 dB

BTS

Apply dynamic Increment and Decrement steps based

on the position of current power level in the PC window

dyn_step_adj: Enables/disables the Dynamic Step Adjustment algorithm

dyn_step_adj_fmpr: Controls the rapidity of a dynamic power reduction


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38April 2000

Optimised Power Control (2)

Dynamic Power Control

Dynamic power increase due to poor qualityDYN_POW_INCR_XX_Q = max [pow_inc_step_size_xx, fhigh(l_rxlev_xx_p - av_rxlev_xx +

pow_inc_step_size_xx)]

The power increases more rapidly if the power is below the power windowthan if it is within it

Dynamic power increase due to low levelDYN_POW_INCR_XX_L = fhigh(l_rxlev_xx_p - av_rxlev_xx + pow_inc_step_size_xx)]

Dynamic power reduction due to good qualityDYN_POW_RED_XX_Q = max [pow_red_step_size_xx, fhigh((dyn_step_adj_fmpr / 10) * (av_rxlev_xx -

u_rxlev_xx_p))]

NO dynamic power reduction due to good level


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39April 2000

Optimised Power Control (3)

Oscillation Prevention

MS uplink power oscillations prevention mechanism

already existed. Activated with mspwr_alg NEW BTS downlink power oscillations prevention

algorithm. Activated withdyn_step_adj

A quality based power reduction will be ignored if:

av_rxlev_dl < (l_rxlev_dl_p + pow_red_step_size_dl + 2 dB)


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40April 2000

Enhanced Congestion Relief

Expand the decision process for handover toinclude the state of congestion at the target cell

Incorporate the added dimension of Time

Band Aware congestion relief

5 New proceduresNon-Imperative handover rejection

Congestion relief handover retry Incoming handover requests

Handover retry

Multi-band MS redirection


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41April 2000

Enhanced Congestion Relief (2)

Non-Imperative Handover Rejection

The BSS rejects an incoming non-imperative(congestion relief) handover if it will causecongestion relief procedures to be triggered in thetarget cell

Avoids the propagation of congestion

Congested

Congested

Congest ion

Relief 1

Congest io

n Relief 2

x


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42April 2000

Congested

Congested


Congestion Relief Handover Retry

The source cell will not attempt a congestion reliefhandover, for a period of time, to a target cell which had

rejected a previous handover attempt

Timer: retry_candidate_period

Timer does not affect imperative retriesCR HO Atmp t

2

CR HO Atmpt

1xRetry_candidate_period


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43April 2000


Incoming Handover Requests

New parameter in the target cell:

congest_at_target: Controls the behaviour of the target cell 0: No action if the cell rejects a handover request 1: Invoke congestion relief if the cell rejects a handover request

If the target cell rejects an incoming handover because it would

trigger congestion relief, and congest_at_target = 1, it will start

congestion relief to empty a channel and inform the source cell(intra-BSS only) in the future that the congestion situation has

disappeared

When the target cell accepts an incoming handover and results in

congestion relief invoked, it never attempts a handover back to

the source cell that started the process


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45April 2000


Multi-band Mobile Station Redirection

New parameter:

mb_tch_congest_thres: (0 - 100%) Percentage point atwhich multi-band mobiles start to be redirected to the

preferred band. The BSS does not allow an incoming band preference handover if

permitting it would cause this percentage to be exceeded

IMPORTANT: Associated Parameters for enhanced CR handover_required_reject_switch = 1 (MSC sends a handover reject message

to the BSC if an external target can not accept the handover)

number_of_preferred_cells = 1 (1 target cell in the handover required message)


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46April 2000

Directed Retry

HO from SDCCH (congested cell) to TCH (neigh.)

Increase the effective capacity of the system

Requires the MSC to support DR procedures

Decision based in a single Measurement Report

SDCCHconnection

DR HO

DR HO

CongestedMicrocell

DR HO's(SDCCH-TCH)

Macrocell


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Congestion Relief No special requirements in the switch More accurate averaging

SDCCHconnection

CongestedMicrocell

CR HO

CR HO CR HO

CR HOCR HO's(TCH-TCH)

Macrocell

More effectivetechnique than

Directed Retry

Documents

WS Prague Power Control