Field Guide Change Alert Field Guide Change Information: Name of
Change:LTE UL power control parameters change Affective Date of
Change: 06/10/2013 Change Number:L12B-E-11Field Guide Reference #:
Ericsson LTE Vol. II Equipment Vendor: Ericsson (LTE)Issuer
Name:Jing XuIssuer Contact #: 9256407057 Description of the Change:
In the space below, describe at a high level what and why this
change is necessary and how it may affect the current systems. This
approved Field Guide Alert is sent as part of the normal Field
Guide Alert process to communicate a change in the National
recommendation for Ericsson LTE configurable parameters. This FGA
is dealing only with the UL power control parameters
pZeroNominalPusch and pZeroNominalPucch which defines the target
Power spectral density (PSD in short) for PUSCH and PUCCH. By
setting pZeroNominalPusch and pZeroNominalPucch to higher value, we
are providing better SINR result for PUCCH and PUSCH, thus more UEs
will be able to meet the minimum SINR request for PUSCH and PUCCH
respectively, provide better throughput and signaling continuity.
The algorithm is explained below:
TocalculatethebitratesitisnotonlyrequiredtoknowthenumberofresourceblocksthatUEis
allocatedbutalsowhatSINRtheseresourcesblocksarereceived.Thisisgovernedbythepower
controlsetting.Uplinkpowercontrolconsistsofopenandclosedloopcomponentsandcontrols
energyperresourceelementappliedforaUEtransmission.Forintra-celluplinkpowercontrolthe
closed loop component adjusts a set point determined by the open
loop power control component. Formula for PUSCH Power Setting Power
control for PUSCH reduces the PSDTX for UEs close to the RBS. The
PSDRX is kept constant. The actual PSDTX is used to calculate SINR
(based on GINR and PSD), used by PUSCH link adaptation. 3GPP
specifies the following PUSCH power setting equation: where: Pmax
is the UE power capability. M is the number of scheduled resource
blocks. is the path-loss compensation factor, which is set to 1, so
the open loop compensates completely for the path loss. Po is the
target PSDrx for each resource block, set according to the
parameter pZeroNominalPusch. Po is common for all UEs in the cell.
mcs is an MCS-specific offset and set to 0. PL is the path loss
estimated by the UE. The f(i) is the closed loop power control
part, while the rest is the open loop power control part. i is a UE
specific power adjustment included in the uplink scheduling grant
on PDCCH.The closed loop power adjustments are used to enforce the
open loop PSDRX target in the RBS. It is updated fast enough to
follow slow fading.Formula for PUCCH Power Setting PUCCH is power
controlled independently via an open loop and a closed loop with
Transmission Power Control (TPC) commands transmitted on PDCCH. The
power setting formula for PUCCH, as per 3GPP TS 36.213, is as
follows: where: Pmax is the UE power capability. P0pucch is the
target PSDrx for PUCCH, corresponding to Po for PUSCH. It is set
according to the parameter pZeroNominalPucch and signaled
separately on BCCH System Information Blocks (SIBs). PL is the
pathloss estimate and is the same as for PUSCH. h(n) is a PUCCH
format dependent value where ncqi corresponds to the number of
information bits for the CQI, and nharq the number of HARQ bits.
F,pucch is an offset that depends on the information transmitted on
PUCCH. g(i) is the current PUCCH power control adjustment state.
The open loop part controls P0pucch, and the closed loop part
controls g(i). Below is a chart that demonstrate the power control
under different path loss condition: Figure 1 Illustration of Power
Levels The figure can be divided into four regions with different
characteristics: Region 1: Here UE power control is working within
the dynamic range. The power control target pZeroNominalPusch is
met and SINR of PUSCH is constant. Region 2: Here the UE is
transmitting at the maximum power. RX power level per resource
block and SINR for PUSCH decreases with a higher signal attenuation
until SINR reach to minimum request SINR for the PUSCH. Region 3:
Here RX power level per resource block and SINR for PUSCH are
constant even though the signal attenuation increases. The number
of allocated resource blocks decreases. Region 4: The number of
allocated resource blocks has reached its minimum, 2 for current
release, and SINR for PUSCH decreases with a higher signal
attenuation. By increasing pZeroNominalPusch, the region 1 will be
shrunk,the Region 2 will be extended further into Region 1 and the
rest of the region unchanged due to limitation on Maximim UE
transmit power.
AstheminimumdesiredSINRlevelattheRBSforbasestationsconfiguredwith2or4receive
antennasaredifferentby4dB,thedefinedpZeroNominalPuschandpZeroNominalPucch
arealso differed by 4dB for different receiver amount. The values
in braces indicate [Level, Value, Units, Class]: pZeroNominalPusch
[EUtranCellFDD=2RX , -100, dBm, Global] is changed from -106 to
-100 with permission of Global. This parameter defines the nominal
component of the UE transmit power for Physical Uplink Shared
Channel (PUSCH) for NodeB with 2 receive antennas.
pZeroNominalPusch [EUtranCellFDD=4RX , -104, dBm, Global] is
changed from -109 to -104 with permission of Global. This parameter
defines the nominal component of the UE transmit power for Physical
Uplink Shared Channel (PUSCH) for nodeB with 4 receive antennas.
pZeroNominalPucch [EUtranCellFDD=2RX , -116,-110, -108 dBm, Local]
initial setting at -116dBm is changed from -120, -110, -108 to
-116, -110, -108 with permission of Local. This parameter defines
the nominal component of the UE transmit power for Physical Uplink
Control Channel (PUCCH). The two higher value are only provided for
sites with high interference from external network such as WIFI
that need to be launched in time. pZeroNominalPucch
[EUtranCellFDD=4RX , -120,-110, -108 dBm, Local] initial setting at
-120dBm is changed from -123, -110, -108 to -116, -110, -108 with
permission of Local. This parameter defines the nominal component
of the UE transmit power for Physical Uplink Control Channel
(PUCCH). The two higher value are only provided for sites with high
interference from external network such as WIFI that need to be
launched in time. The following KPIs change were observed when the
change is made:Improved Accessibility due to RRC success rate
improvement. Improved Retainability due to reduction on dropcalls
due to handoverexecutionfailure; this improvement is more obvious
in dense urban area. Improved UL MCS with more 16QAM usage and
better ack rate from HARQ. Improved SINR for both PUSCH and PUCCH.
Slightly increased PUSCH RSSI, no obvious difference on PUCCH RSSI.
Reduced UL PRB utilization indicating UL efficiency improved.
Improved Tnol due to improved RRC process, this is only observed in
dense urban area. Improved UL&DL throughput according to
speedtest.net result. The trial was done in SF, SAC and SD market.
Test report for SF and SAC market can be found here. Note:The
parameter values indicated in the Ericsson LTE Gold Standard
located at the Gold Standards Governance Team website supersede any
parameter values recommended by any Field Guide Alert or other
document that provide recommendations for parameter values.Please
consult the Ericsson LTE Gold Standard when in doubt.
Implementation of the Change: pZeroNominalPusch and
pZeroNominalPucch are an eNB level parameter belonging to
EUtranCellFDD MO class.. No action needed by the markets, these
changes will be implemented by the MNT team. For any questions
regarding the timeline for specific market please contact
Christopher Wyatt ([email protected]).
