Parameter Tuning for DPCH_v4_penting

1 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials

Company Confidential

Optimization based on Ptx pwr & DYLO statistic

Apr. 2006

C&I, Network Design & Performance

James & water

Nokia Taiwan



ProblemBig Coverage

Link power unbalance

Many Users

Code blocking &

Short of CE or Transmission

High radio link power

Big Interference Radio link rejection or shortage

& Handover fail

High BLER & Lower Ec/No

Coverage hole Poor Network Quality (call failure)



Which cells need to trace??

•Cells can be defined as following;-. Overloaded cells which require Ptx power more than 43dBm

-. Overloaded cells with high code, CE and transmission blocking ratio

-. Cells with big coverage ( radio link power limited cells )

• Phase 1 & 2 cells use 20W(43dBm) WPA but Phase 3 cells use 40W(46dBm). Nevertheless, Radio link power parameters are set to the same value as following;

PtxDPCHMax : -3dB

PtxDPCHMin : -28dB

PtxDLabsMax : 50dBm

What is current issue??



Overloaded cells

Some cells reach overload power range over 43dBm



Current CHT network summary (only North area)

This statistic is calculated from counter data for 10days .

Most of overloaded cells come from Ph3 sites

Percentage out of total overloaded cells in each phase



e.x) 38577_coverage overlay too much



Tuning parameter

• What are benefits from changing

“Minimum DPCH -31dB and PtxDLabsMax 40dBm“ ??

- Share Radio link resources among 3G users

- Ptx power to be operated within Marginal load areaMarginal load area

- Can prevent UE from suddenly getting worse Ec/No and Eb/No so that provide stable cell coverage

- No need to transmit unnecessary power for users closed to sites so that can improve Ec/No

- Handover performances can be improved so call drop ratio will be decreased.



Downlink Radio power from E2K after changing

SF8

SF16

SF128

SF256

Sometime downlink power needs more than max. 31dBm for Voice



SF8

SF16

SF128

SF256

Sometime downlink power needs more than max. 41dBm for PS 384K

Downlink Radio power from E2K before changing



RL pwr for SF8 & SF16 After & Before changing

SF8

SF16

Max. 38dBm

Max. 41dBm

Min. 21.5dBm

Min. 25dBm

After

After

Before

Before



SF128

SF256

Min. 18dBm

Min. 15dBm

Min. 18dBm

Min. 15dBm

After

After

Before

Before

RL pwr for SF128 & SF256 After & Before changing



8577U set to 40dBm

Not Overloaded any more

Overloaded

PtxDLabsMax

40dBm

50dBm



8561U set to 40dBm

Not Overloaded any more

Overloaded

PtxDLabsMax

40dBm

50dBm



3369U without changing

Still Overloaded



8374U without changing

Still Overloaded



DYLO_8577U

After changing, REC_PREP_MOD ratio due to DYLO could be

increased



Current CHT network summary (only North area)

This statistic is calculated from counter data for 10days .

Most of overloaded cells come from Ph3 sites

Percentage out of total overloaded cells in each phase



Dynamic Link Optimization in PS





RL Reconfiguration Counters: Prepare

• Counters incremented when RNC sends RADIO LINK RECONFIGURATION PREPARE message:

REC_PREP_SRNCREC_PREP_SRNC

RECONF_PREP_DCH_ADD_SRNCRECONF_PREP_DCH_ADD_SRNC

RECONF_PREP_DCH_DEL_SRNCRECONF_PREP_DCH_DEL_SRNC

1 for each PREPARE 1 for each PREPARE message (SRNC and message (SRNC and DRNC)DRNC)

1 for each DCH addition 1 for each DCH addition requested in the message requested in the message SRNC and DRNCSRNC and DRNC

1 for each DCH deletion 1 for each DCH deletion requested in the message requested in the message SRNC and DRNCSRNC and DRNC

REC_PREP_MOD_DYN_LNK_SRNCREC_PREP_MOD_DYN_LNK_SRNC1 for each DCH modification due 1 for each DCH modification due to DyLo requested in the to DyLo requested in the message SRNC onlymessage SRNC only



DYLO statistics

For some cells REC_PREP_MOD ratio due to DYLO is more than 30%



Ex.2) cell 3357 with high DYLO attempt



Example DLO : PtxDLabsMax 50 dBm, PtxTotalMax 43dBm/46dBm

DL

pw

r (d

Bm

)

PtxTotalMax 43dBm/46dBm

PtxPrimaryCPICH 33dBm

PtxPrimaryCPICH – CPICHtoRefRABoffset = 31 dBm

PtxDLabsMax 50 dBm

Calculated max RL pwr

Calculated max RL pwr - DLOptimisationPwrOffset

• This is where DLO triggers. (If PtxDLabsMax is set high)•384kbps:38dBm•128kbps:37.387dBm

Default hidden value is 2dB

reftxP ,

max,txP

Ptx, threshold

384kbps:40dBm

128kbps:39.387dBm



PtxDPCHMax

• Parameter defines the maximum code channel output power for the power control dynamic range of BTS. The maximum transmission power is calculated by adding the value of the parameter to the BTS maximum output power (Pmax in dBm).

range: -3 ... 0dB , step 0.1dBdefault: -3 dB

PtxDPCHMin

• Parameter defines the minimum code channel output power for the power control dynamic range of BTS. Minimum transmission power is calculated by adding the value of the parameter to the BTS maximum output power (Pmax in dBm).

range: -60 ... –28dB , step 1dBdefault: -28 dB

Relevant DL Power Parameters



PCrangeDL

• The parameter defines the downlink power control range in relation to the maximum allocated transmission power of the radio link

• The minimum transmission power is achieved by subtracting the value of the parameter from the maximum transmission power of the radio link

• However, the minimum BTS output power of the code channel defines the absolute lower limit for the minimum transmission power

range: 0 ... 25 dB, step 1 dB default: 18dB

DL Power Control Dynamic Range



Planned Maximum DL Ptx of the Radio Link

PtxDLabsMax

• The planned maximum downlink transmission power of radio link. This parameter is used in the downlink power allocation when CCTrCH includes one or more DCH's of interactive or background traffic class RAB's. The allocated power of a radio link cannot exceed the value of this parameter. The parameter is set separately for each cell. This parameter is the planned maximum, not the physical limit.

range: -10 ... 50 dBm, step 0.1 dBm

default: 50 dBm



Inactivity timer

Documents

Parameter Tuning for DPCH_v4_penting