wcdma power calculation guide

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WCMDA POWER CALUCLATION GUIDE Security Level: Internal

Case Title WCDMA Power Calculation Guide

Author Name Muhammad Usman Khalid Khan / m0026399

The Related Project WCDMA !etwor" U# $radation Pro%ect

WCDMA Power Calculation Guide

Abstract ： The abstract of this guide is related to Power

calculation including Max Power of Cells and all associated commoncontrol channels in UMTS. The reason for writing this guide as it

would be very helpful when you will upgrade your software version

like from !" to !# or later$ to avoid upgrade fails because the

maximum transmit power of a cell is lower than the sum of the

transmit power of channels in the cell. %lso it will give you a better

understanding of power which is shared among many channels.

&e have to upgrade our software version from '()))!"C#)) to

'()))!#C)) so we have to check in the said UMTS *etwork that

the comparision of CellMaxTxPower to Total number of downlink

Channels powers before execution.

This guide contains the idea behind how the calculation has been

done in all our network to avoid activity failure and give good

perception of Power in &C+M%.

Keywords: Power$ Control channels$ adio$ Planning$ ,ptimi-ation$

$ Upgrade

1 !ituation

There are total !!"/ sites in this UMTS network and di0erent

Maximum transmit powers are set in the network. The power

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calculation has to be done on every cell which re1uires some

strategy to 1uickly complete this task e0eciently. %ll this mentioned

in the later part of this guide how calculation done and what was the

criteria.

2efore going in the details here is the information of all the channels

which have been used in the calculation.

• Maximum Transmit Power of Cell

Sum of the maximum transmit power of all +3 channels in a cell.

To fetch this information from M4))) the command is as follows

LST UCELL: LstType=ByCellId, CellId=11234;

• P5CP6C7 Transmit Power of Cell

T8 power of the P5CP6C7 in a cell. This parameter should be set

based on the actual system environment such as cell coverage

9radius: and geographical environment. or the cells to be covered$

the downlink coverage must be guaranteed. or the cells re1uiring

soft handover area$ this parameter should satisfy the proportion of

soft handover areas stipulated in the network plan.

The value of this parameter must satisfy the following relationship;

<Min Transmit Power of PCP6C7< => <PCP6C7 Transmit Power<

=><Max Transmit Power of PCP6C7<


LST UPCPICH: CellId=11234;

*ote; The P5CP6C7 transmit power must be higher than the minimum

pilot power and lower than the maximum pilot power.

• P6C7 Power ,0set and %6C7 Power ,0set

P6C7 Power ,0set is the di0erence between the transmit power of

P6C7 and that of PCP6C7





%6C7 Power ,0set is the di0erence between the transmit power of

an %6C7 and that of PCP6C7.


LST UCHPWROFFSET: CellId=11234;

• 2C7 Transmit Power

This is the ,0set of the 2C7 transmit power from the P5CP6C7

transmit power in a cell. 6f the value is set too small$ the U?s on the

cell edge cannot receive the system messages properly. This

problem a0ects the coverage of the downlink common channel and

furthermore the coverage of the cell. 6f the value is set too great$ it

causes interference to other channels$ occupies the downlink

transmit power$ and a0ects the cell capacity.


LST UBCH: CellId=11234;

• PSC7 Transmit Power

This is the ,0set of the PSC7 transmit power from the P5CP6C7

transmit power in a cell. 6f the value is excessively low$ U?s at the

edge of cells fail in network searching$ resulting in in@uence on

coverage of the downlink common channel. This Anally a0ects the

cell coverage. 6f the value is excessively high$ the power resources

are wasted$ and other channels are interfered seriously$ thus the

cell capacity is in@uenced.

To fetch this information from M4))) the command is as

follows

LST UPSCH: CellId=11234;

• SSC7 Transmit Power

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This is the o0set of the SSC7 transmit power from the P5CP6C7

transmit power in a cell. 6f the value is excessively low$ U?s at the

edge of cells fail in network searching$ resulting in in@uence on

coverage of the downlink common channel. This Anally a0ects the

cell coverage. 6f the value is excessively high$ the power resources

are wasted$ and other channels are interfered seriously$ thus the

cell capacity is in@uenced.


follows LST USSCH: CellId=11234;

• PC7 Transmit Power

This is the o0set of the PC7 transmit power from the PCP6C7

transmit power in a cell. 6f the value is set too small$ the U?s on the

cell edge cannot receive the paging message properly. This problem

a0ects the coverage of the downlink common channel and

furthermore the coverage of the cell. 6f the value is set too great$ it

causes interference to other channels$ occupies the downlink

transmit power$ and a0ects the cell capacity.


follows

LST UPCH: CellId=11234;

• Maximum %C7 Transmit Power and %C7 6+s

This is the o0set between the %C7 transmit power and P5CP6C7

transmit power in a cell. 6f MaxachPower is set excessively low$ a

U? positioned at the cell edge may fail to receive the services and

signaling carried over the %C7$ in a correct way. This will impact

the downlink common channel coverage and thus the cell coverage.

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6f MaxachPower is set excessively high$ other channels will be

interfered and more downlink power resources will be occupied. This

will conse1uently impact the cell capacity.

%C7 6+ is used to uni1uely identifying a %C7 bearing the common

transport channel in a cell.


follows

LST UFACH: CellId=411;

• *umber of %6C7s.

The deAned number of %6C7s can be identied through %6C76+.


LST UAICH: CellId=11234;

• Maximum Transmit Power and Minimum Transmit Power of P5CP6C7

Maximum T8 power of the PCP6C7 in a cell. This settings

should be set based on the actual system environment such

as cell coverage 9radius: and geographical environment$ and

the cell total power. &hen the ratio of soft handover areas

keeps the same$ the downlink coverage cannot be promoted

by the increase of PCP6C7 power.

Minimum T8 power of the PCP6C7 in a cell. This parameter

should be set based on the actual system environment such

as cell coverage 9radius: and geographical environment.

?nsure that MinPCP6C7Power is set under the condition of a

proper proportion of soft handover area$ or under the

condition that no coverage hole exists.


follows

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LST UPCPICH: CellId=11234;

" Analysis%s 6 mentioned above to avoid discrepancy in power calculation the

strategy has been developed which divided in di0erent combinations

according to the deAned Maximum transmit power settings which has

been discussed in the later part. 6n this part the formulas has been

mentioned which have been used in the calulation. This all is based on

+ownlink channel mapping based on the below diagram.





ormulas Used

2elow are the formulas which has been used in the calculation$ refer

attached excel also in case of any confusion.

C?33 M%86MUM T%*SM6T P,&? B P,&? 9!)$9M%8T8P&!):!):

PCP6C7 B P,&? 9!)$9PCP6C7!):!):

P6C7 B P,&?9!)$9P6C7DCP6C7!):!):

%6C7 B P,&?9!)$9%6C7DCP6C7!):!):E*um of %6C7

2C7 B P,&?9!)$999M%892C7$PSC7$SSC7:DPCP6C7::!)!)::

%C7 B P,&?9!)$999M%89%C7$PC7:DPCP6C7::!)!)::E*um of %C7

T,T%3 C,MM,* C7%**?3 P,&? B PCP6C7DP6C7D%6C7D2C7D%C7

COMPARE CELL MAXIMUM TRANSMIT POWER WITH TOTAL

COMMON CHANNEL POWER

IF MAXIMUM TRANSMIT POWER >= TOTAL COMMON CHANNEL

POWER → PASS

IF MAXIMUM TRANSMIT POWER < TOTAL COMMON CHANNEL

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POWER → FAIL

PowerFormula.xlsx

# Wor$in% !trate%y

The mapping between Maximum Transmit Power and all downlink channel

power has been done with di0erent combinations or scenarios.

The di0erent combinations are based on Maximum transmit power which

are currently using in this UMTS network.

irst all the relative data of all sites has been gathered in one sheet by

di0erent commands as mentioned above through latest CGMM3s of all

*Cs. 2elow mentioned depicts the same.

6n the above diagram the columns highlighted with yellow are constant in

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this network and set on one value only.

%fter processing the above data it has been observed that there were H

di0erent types of MaxT8Power set in the network so we need at least H

combinations to cross check whether the maximum transmit power of all

cells is greater or e1ual to other common channels.

urther calrify here that every time the MaxT8P& will be change and

correspondingly the maximum power of the other downlink channels and

max number 9%C7 I %6C7 6+: will be selected.

Combiatio ! "#

6n combination ! the highest set power has been taken which is "() d2m

correspondingly the cell whose CP6C7 power is highest according to this

Alter which is JK) has been taken$ the reason to select the highest CP6C7

Power is because of this has the highest weightage in the power

calculation means this will consume max power also the same strategy

has been setup with other channel powers to check the peak case.

%fter calculation as per the above formulas it has been concluded that Cell

Maximum transmit power is greater than the total channel power as

re@ecting in the below table.

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Power &' Cell(d)m* +esult（m,）

CellMa-.-Power 90 932123

PCPC 360 39140406

PC 5 932123

AC 56 4000

)C 520 24411632

7AC 40 400236

P8C 50

88C 50

PC 520

!um o' AC 4

!um o' 7AC 2

Ma- o' PCPC 390

Min o' PCPC 30

.otal o' Channels 413440340

Combiatio! "$

The same strategy we use in the next round select the next MaxT8Power

of "/H and selecting its corresponding max values of CP6C7 power P6C7$

%6C7$ 2C7$ %C7 and other common channels.

,ne thing which is signiAcant to notify here that the *umber of %C7 and

*umber of %6C7 is important in the calculation as if their number is any

combination their weight age will be high in the calculation which is

prominent in overall a0ect.

Power &' Cell(d)m* +esult（m,）CellMa-.-Power 1 6029164

PCPC 310 63093

PC 5 4219242

AC 56 41193492

)C 520 39140406

7AC 40 4116669

P8C 50

88C 50

PC 520





!um o' AC 4

!um o' 7AC 2

Ma- o' PCPC 343

Min o' PCPC 36


Ot%&r Combiatios

,ther all remaining K combinations has mentioned below based on

changing max tx power and its corresponding maximum values of other

common channels.

The result is based on above mentioned formulas.



PCPC 390 932123

PC 53 39140406

AC 56 49926234

)C 520 04412336

7AC 40 20000

P8C 50

88C 50

PC 520

!um o' AC 4

!um o' 7AC 2

Ma- o' PCPC 0

Min o' PCPC 30




PCPC 360 39140406

PC 5 932123

AC 56 4000

)C 520 24411632

7AC 40 400236





P8C 50

88C 50

PC 520

!um o' AC 4

!um o' 7AC 2

Ma- o' PCPC 31

Min o' PCPC 32



CellMa-.-Power 29420922PCPC 30 04412336

PC 5 4000

AC 56 4219242

)C 520 3462266

7AC 40 426494619

P8C 50

88C 50

PC 520

!um o' AC 4!um o' 7AC 2

Ma- o' PCPC 00

Min o' PCPC 30




PCPC 360 39140406

PC 5 932123

AC 56 4000

)C 520 24411632

7AC 40 400236





P8C 50

88C 50

PC 520

!um o' AC 4

!um o' 7AC 2

Ma- o' PCPC 31

Min o' PCPC 30


Power &' Cell(d)m* +esult（m,）CellMa-.-Power 30 04412336

PCPC 260 39140406

PC 5 932123

AC 56 400

)C 520 24411632

7AC 40 400236

P8C 50

88C 50

PC 520!um o' AC 4

!um o' 7AC 2

Ma- o' PCPC 21

Min o' PCPC 22




PCPC 260 39140406

PC 5 932123

AC 56 400

)C 520 24411632

7AC 40 400236

P8C 50

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88C 50

PC 520

!um o' AC 4

!um o' 7AC 2

Ma- o' PCPC 21

Min o' PCPC 22


rom all the above calculations it has been depicted that Maximum

transmit power is greater in every scenario from the total channel power

hence all the results are in pass category.

6n case if you And the Maximum transmit power of a cells is less than

common control channel power then either you have to increase the

maximum transmit power or you have to reduce CP6C7 power to avoid any

issue.

&' (n a Nutshell ) !ummary

7ere 6 would like to mention that this guide would be very helpful while

doing some immense activities to avoid failure. %lso you can have the

better understanding of Power conAguration in &C+M% which will give you

good visibility during optimi-ation and planning phases that tuning of

power and its consumption.

6 hope this guide book will be helpful and interesting for all concerned

colleagues.

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wcdma power calculation guide

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