05 b rrm dl PARAMETER

For internal use only
1 © Nokia Siemens Networks /
DL LA and PC

Comparison of DL and UL link adaptation for
PSCH
• Downlink
– fast
 1 TTI
– channel aware
 CQI based
– MCS selection
 1 out of 0-28
– output
 MCS
 TBS
– UE capabilities support
 max. TBS per TTI
– up to 64QAM support
• Uplink
– slow periodical
 ~30ms
– channel partly aware
 average BLER based
– MCS adaptation
 +/- 1 MCS correction
– output
 MCS
 ATB
– UE capabilities support
 power headroom
 QoS profile
– up to 16 QAM support

DL LA overview
UE eNodeB
CQI, RI (and PMI)
DL Data
Outer Link Quality Control (OLQC)
•Corrects reported CQI based on Ack/Nack
• Target BLER - dlTargetBler (10% by default)
UE calculates CQI:
•Based on RS and
data CE SINR
(assumption?)
•Wideband and sub-
band CQIs can be
reported.
UE calculates RI:
Based on tx branch
correlation
(assumption?)
HARQ Ack/Nack
Dynamic MIMO mode switching
•Selects MIMO mode based on CQIcorr and RI
•Switching decisions in 100ms intervals
•Adds additional compensation to CQIcorr based on RI
and MIMO mode
MCS selection
•Based on CQI corrected by OLQC and MIMO switching

DL LA - input parameters description
• CQI values (from OLQC)
– corrected wideband/frequency selective CQIs
• Scheduling information (from DL SCH)
– list of PRBs/RBGs assigned to the UE
– upper or lower downlink rate limit
• HARQ feedback (from DL HARQ)
– ack/nack information
• UE capabilities (from RAC)
– maximum allowed number of bits for single(all) DL SCH transport
block(s) within a TTI according to 3GPP-36.306
• MiMo mode selection (from MiMo-MC)
– single/double code word case
• Rank indicator (from OLQC)

DL LA – algorithm overview
• Algorithm has a UE scope
and is working on TTI basis
• Performed separately for each
code word if only code word
specific CQI is available
(from RL20)
Retrieve Default MCS
Start
End
Yes
Dynamic AMC active?
Determine averaged CQI
value for allocated PRBs
Use same MCS as for initial
transmission
Determine MCS
No
Yes
HARQ retransmission?
No
Use default MCS
Link adaptation
disabled
Retransmission
Start with default
MCS

• Select CQI values related to the
PRBs/RBGs which have been
assigned to UE by DL SCH
• Map these CQIs to CIRs values
by means of R&D look-up table
• Calculate average CIR value
• Map average CIR to average CQI
(possible interpolation between
full CQI steps defined by 3GPP)
• If only wideband CQI is available above
procedure is obsolete
CQI index Modulation
Coding Rate
x 1024
Efficiency
0 out of range
1 QPSK 78 0.1523
2 QPSK 120 0.2344
3 QPSK 193 0.3770
4 QPSK 308 0.6016
5 QPSK 449 0.8770
6 QPSK 602 1.1758
7 16QAM 378 1.4766
8 16QAM 490 1.9141
9 16QAM 616 2.4063
10 64QAM 466 2.7305
11 64QAM 567 3.3223
12 64QAM 666 3.9023
13 64QAM 772 4.5234
14 64QAM 873 5.1152
15 64QAM 948 5.5547
4-bit CQI table, 3GPP 36.213, table 7.2.3-1
DL LA – determine average CQI for assigned PRBs 2/2
If 64QAM modulation
is not enabled in the cell
CQI index is limited to 9

OLQC – CQI Adaptation
• Outer Link Quality Control (OLQC) adapts the channel quality information
that is used by the scheduler and link adaptation to achieve target block
error ratio (BLER) for the first transmission of a Transport Block
• OLQC compensates any non-idealities of the link adaptation :
• CQI estimation error of the UE
• CQI quantization error
• CQI reporting error
• Time delay between CQI measurement and the reception of the subsequent data
block
• CQI interpolation error
• Errors due to CQI averaging of PRBs
• dlOlqcEnable parameter is used to enable/disable the outer link quality
control. When outer link quality control is disabled then the corrected CQI
values correspond to the reported CQI values.

OLQC algorithm – input parameters description
• CQI reports (from UL L1/L2 sig):
– wideband
– frequency selective
– code word specific (starting from RL20)
• HARQ feedback (from DL HARQ)
– ack/nack information
• MiMo mode selection (from MiMo-MC)
– single/double code word case
OLQC algorithm – output parameters description
• Corrected CQI reports (to DL LA):
– wideband
– frequency selective
– code word specific (starting from RL20)

CQI adaptation/correction algorithm
• OLQC adds a CQI offset ( ) to the wideband/frequency
selective and code word specific (starting from RL20) CQI
values
• Delta CQI is initialized in the following way
CQI

)
CQI(
)
,
,
(
CQI
)
,
,
(
CQI rep
reported
rep
corrected t
t
f
x
t
f
x 


)
CQI(
)
,
(
CQI
)
,
(
CQI reported
corrected t
t
x
t
x 


init
setup ΔCQI
)
(
ΔCQI 
t

• Delta CQI calculation
– single code word case
– double code word case
– balance condition




















N/A.
feedback
HARQ
first
for
),
1
(
CQI
NACK,
feedback
HARQ
first
for
),
CQI
,
CQI
)
1
(
CQI
max(
ACK,
feedback
HARQ
first
for
),
CQI
,
CQI
)
1
(
CQI
min(
)
(
CQI min
stepdown
max
stepup
t
t
t
t
stepdown
target
stepup
target CQI
BLER
CQI
)
BLER
1
( 




















































N/A.
N/A
feedbacks
HARQ
first
for
),
1
(
CQI
N/A,
NACK
feedbacks
HARQ
first
for
),
CQI
,
CQI
)
1
(
CQI
max(
N/A,
ACK
feedbacks
HARQ
first
for
),
CQI
,
CQI
)
1
(
CQI
min(
NACK,
ACK
feedbacks
HARQ
first
for
),
CQI
),
CQI
,
2
/
)
CQI
CQI
(
)
1
(
CQI
min(max(
NACK,
NACK
feedbacks
HARQ
first
for
),
CQI
,
CQI
)
1
(
CQI
max(
ACK,
ACK
feedbacks
HARQ
first
for
),
CQI
,
CQI
)
1
(
CQI
min(
)
(
CQI
min
stepdown
max
stepup
max
min
stepdown
stepup
min
stepdown
max
stepup
t
t
t
t
t
t
t

• Provide DL LA with:
– corrected wideband CQI
– corrected frequency selective CQI
– code word specific (from RL20)
)
CQI(
)
,
,
(
CQI
)
,
,
(
CQI rep
reported
rep
corrected t
t
f
x
t
f
x 


)
CQI(
)
,
(
CQI
)
,
(
CQI reported
corrected t
t
x
t
x 



OLQC - O&M configuration
Parameter,
abbreviated Name
(mand)
Description
(mand)
Access
RW
R
(mand)
Parameter
Type
O: operator
configurable
V: vendor
configurable
(mand)
Range,
Stepsize/Granul
arity, Units,
Special Value
(e.g. "not
defined")
(mand)
Default
Value
(opt)
Parameter
Scope
(PLMN,
RAN, Nb,
Cell, Chl)
Proposed
MOC
(mand)
Reference
e.g. 3GPP
name or
other
(opt)
Multiplicity
dlOlqcEnable
Switch to enable/disable
OLQC
RW O
Boolean (0/1)
0=True 1=False
True Cell - 1
dlOlqcDeltaCqiIni Initial value of CQI offset R V
-15 to +15
in steps of 0.1
-0.5 BTS - 1
dlOlqcDeltaCqiMax
Maximum value of CQI
offset
R V
0 to 15
in steps of 0.1
1 BTS - 1
dlOlqcDeltaCqiMin
Minimum value of CQI
offset
R V
-15 to 0
in steps of 0.1
-3 BTS - 1
dlTargetBler
Target block error ratio of
transport blocks for 1st
transmission
RW O
0.001 to 0.999
in steps of 0.001
0.10 Cell - 1
dlOlqcDeltaCqiStepUp
CQI offset increase for an
ACK
R V
0.001 to 1
in steps of 0.001
0.125 BTS - 1

Dynamic MIMO mode (RL10)
Depending on Radio Conditions:
switch between Diversity and Spatial Multiplexing
- Open loop MIMO Switch Algorithm
- Open loop adaptive MIMO Algorithm
- Support of UE Capabilities
- UE basis
- CQI and Rank Information: used as switching criteria
Diversity
x
Spatial
Multiplex

Dynamic MIMO mode
Simulation Results (Source 4GMAX)

Dynamic MIMO mode
Inactivity
: aging
RI
Time
CQI
Time
Inactivity
: Aging
applied
Filtered
Filtered:
cqi, ri
• Switching decision based on CQI, RI
• Frequency: rather low (100 msec..seconds)
Downgrade Switch::
If
mimoCQI <= mimoOlCqiThD
or
mimoRANK <= mimoOlRiThD
Upgrade Switch :
If
mimoCQI > mimoOlCqiThU
and
mimoRANK > mimoOlRiThU
mimoOlCqiThD
mimoOlCqiThU
mimoOlRiThU
mimoOlRiThD

MIMO CQI COMPENSATION EXAMPLE,
(dlMimoMode=3)
CQI
TIME
Compensated
CQI
CQI and RI
reported by UE
Transmission mode
changed to OL-SM by
MIMO mode control
RI=1 RI=1 RI=2
RI=2
RI=2 RI=2
RI=2 RI=2
cqiCompTdRi2Ol
UE-reported RI
changes to 2, TM is still
tx diversity
cqiCompSmRi1Ol
RI=1 RI=1
UE starts reporting
RI=1, but OL-MIMO still
in use
Default cqiCompTdRi2Ol = 3
Default cqiCompSmRi1Ol =-3

Generic Parameters
RL20

OL MIMO – Parameters (not modifiable mostly)

CL MIMO – Parameters (for RL20)

PDCCH Scheduling

Introduction to PDCCH
• Physical channel for Downlink Control Information (DCI)
i.e. resource assignments, PC commands
• DCI can be dedicated for a group of UEs (common
signaling) or to a specific UE (dedicated signaling)
• Allocation rules
– 0…3 OFDM symbols per subframe
– 2…4 OFDM symbols per subframe (1.4 MHz; RL20)
– Aggregated on CCEs
– QPSK only but different aggregation levels (AGG levels)
Cell-specific RS (port 0)
Cell-specific RS (port 1)
Resource Element Group (REG) = 4 REs
Control Channel Element (CCE) = 9 REGs
t
f
Physical Resource Block (PRB)
PDCCH
format
Number of
CCEs
Number of Resource
Element Groups
Number of
PDCCH bits
0 1 9 72
1 2 18 144
2 4 36 288
3 8 72 576

1-CCE
8-CCE 2-CCE
4-CCE
• Macro cell case #1
• Uniform UE distribution
Main target of DL-AMC-CCH
• Similar to data transmission, it is necessary to make a signaling
(PDCCH) robust enough for poor UEs (low SINR, e.g. at the cell-edge)
• Transmission with low ECR (Effective Coding Rate) leads to increased
resource utilization which reduces the number of scheduled UEs; thus
good UEs should occupy less PDCCH resources and operate with
lower number of CCEs (higher ECR)
– 7 UEs (5 MHz), 10 UEs (10 MHz), 20 UEs (20 MHz)
• Any Link Adaptation technique must deal with a trade-off between
signaling robustness (coverage) and signaling capacity

CQI Measurements filtering
pdcchCQI(t) = (1-pdcchCqiAvg)*pdcchCQI(t-1) + pdcchCqiAvg*newCqi
• DL-AMC-CCH requires to operate with CQI reports
filtered based on the historical reporting and newly
calculated CQI.
• Initial value of pdcchCQI(0) corresponds to CQI
which is required to set the default AGG level for DCI
format 1.
pdcchCQI(0) = F-1(pdcchAggDefUe)
• CQI filter ages last CQI report every 10 ms if no new
ones are available.
pdcchCQI(t) = rdPdcchCqiAge*pdcchCQI(t-1)
t
CQI1
10ms 10ms 10ms 10ms
CQI2 CQI3 CQI4
More robust AGG levels…
• Filtered CQI might be shifted according to cell-specific
CQI shift.
E.g. all UEs in the cell may be forced to switch to higher
AGG levels at the cost of PDCCH capacity.
pdcchCQI(t) = pdcchCQI(t) + pdcchCqiShift
• CQI filter operates with wideband CQI reports and
Rank Information. The effect of OLLA/OLQC can be
disabled.
• MIMO compensation is needed because the reported
CQI is smaller than for single codeword transmission,
however if Rank Information is not available, Rank=1 is
assumed (no compensation).
• For open loop MIMO (RL10) CQI for Stream1 equals
Stream2
Rank=1 
newCQI = WIDEBAND_CQI_Stream1 +
DELTA_CQI*rdPdcchOllaUsed
Rank=2 
newCQI = (WIDEBAND_CQI_Stream1 +
WIDEBAND_CQI_Stream2)/2 + pdcchXXComp +
DELTA_CQI*rdPdcchOllaUsed
To CQI-to-Aggregation Mapping unit…
pg1
pg2

pg1 CQI-Ageing is stopped when pdcchCQI(t)=0 or pdcchCQI(t) falls below the threshold determines by DCI format 1 with the default AGG
level (taken from
Piotr Godziewski, 1/18/2010
pg2 Reverse function F-1(pdcchAggDefUe) can be calculated using the formula:
CQI=
Piotr Godziewski, 1/18/2010

CQI-to-Aggregation Mapping unit
CQI from DL-AMC/DL-OLQC
CQI filtering/processing
Filtered, compensated
and shifted CQI
All DCI
formats…
1
CQI-to-Aggregation Mapping
REQUIRED_AGG_LIST =
{
UE-1: pdcchCQI, AGG-DCI0, AGG-DCI1, …;
UE-2: pdcchCQI, AGG-DCI0, AGG-DCI1, …;
…;
UE-k: ...;
}
DLS_INPUT_LIST =
{
Broadcast, Tag, DCI-format, CSS, Prio-A;
Paging, Tag, DCI-format, CSS, Prio-B;
RACH Response, Tag, DCI-format, CSS, Prio-C;
Preamble Assignment, Tag, DCI-format, CSS, Prio-D;
Message 4 Assignment, Tag, DCI-format, CSS, Prio-E;
UE-1, Tag, DCI-format, USS, Prio-X;
UE-2, Tag, DCI-format, USS, Prio-Y;
…;
UE-k: ...;
}
ULS_IINPUT_LIST =
{
UE-1, Tag, USS, Prio-X;
UE-2, Tag, USS, Prio-Y;
…;
UE-k: ...;
}
• CQI-to-Aggregation Mapping unit relies on UE-
specific CQI information to build the list of required
AGG levels for all possible DCI formats for every
active UE (UE which appears on the DL/UL
scheduling list).
• REQUIRED_AGG_LIST must refer to all active
UEs so that the schedulers know how many
resources are needed to allocate them.
• Common signaling (e.g. Broadcast, Paging, etc.)
is not considered at this step; the mapping affects
UE Search Space (USS) only.
1a
…

rdPdcchAggTables
• SINR-vs-BLER tables have been
obtained from 4GMax LL
simulator (EPA05, 2x2MIMO) for
two representative payload sizes
of 45 bits and 60 bits.
• The PDCCH performance
should aim at 1% target BLER.
• SINR targets have to be
translated to CQI thresholds.
• The mapping table is not
sufficient. R&D in-built table
must consist of thresholds for all
possible DCI formats (various
payload size). A scaling factor
(SF) is applied.
CQI = 0.51*SINR + 5.3
Mapping table for 45/60 bits payload composed
based on CQI-to-SINR formula (4GMax)
SFsmallDCI = 10*log10(DCI_size/45)
SFlargeDCI = 10*log10(DCI_size/60)

rdPdcchAggTables
• After post-processing of 4GMax output, the
table is ready to be used by the CQI-to-
Aggregation Mapping unit.
• The table is valid for 10MHz bandwidth,
however the operator can adjust the
thresholds by using O&M parameter
pdcchCqiShift.
• If PDCCH AMC is disabled or CQI is outdated,
pdcchAggDefUe will be applied to all DCI
formats of all UEs.
Mapping table for 45/60 bits payload composed
based on CQI-to-SINR formula (4GMax)
Full rdPdcchAggTables for all available DCI formats (10MHz system bandwidth)
CQI = 0.51*SINR + 5.3
SFsmallDCI = 10*log10(DCI_size/45)
SFlargeDCI = 10*log10(DCI_size/60)

PDCCH Scheduling - Parameters
Short
Name
Description
Range/
Step
Default
Value
Parameter
Scope
Remark
enableAmcPdcch Enable/disable CQI-based
AMC for PDCCH. In case the
parameter is disabled, the
default AGG level is used.
true/false true Cell Changing parameter requires
object locking.
Operator configurable.
pdcchAggDefUe Default AGG level for
PDCCH in case
enableAmcPdcch==false or
(enableAmcPdcch==true and
there are no valid CQIs
available).
1 (0), 2
(1), 4 (2),
8 (3)
4 (2) Cell Changing parameter requires
object locking.
pdcchCqiAvg Averaging constant for CQI
measurement filter.
0.05...1,
step 0.05
0.5 BTS Not modifiable.
Vendor configurable.
pdcchCqiShift The fine-tuning parameter to
adjust measured and
averaged CQI.
-10...10,
step 0.1
- BTS Changing parameter requires
object locking.
pdcchOlComp CQI compensation for open
loop MIMO mode.
0...10,
step 0.1
3 BTS Not modifiable.
pdcchClComp CQI compensation for closed
loop MIMO mode.
0...10,
step 0.1
3 BTS Not modifiable.
pdcchCqiHist The time which old CQI is
remembered for (than
fallback to the default AGG
level).
0...1000
ms, step
1 ms
30 ms BTS Not modifiable.

DL power control, RL10
RL10: (static) Cell Power Reduction
• based on single parameter CELL_PWR_RED = 0.0, 0.1 … 10.0 dB
•  cell size adjustment and coverage control
• flat Power Spectral Density (PSD)
• semi-static MIMO_COMP (if enabled)
PSD
Frequency
PSD=(Max_TX_Pwr – CELL_PWR_RED) – 10*log10( 12*# PRBs)
Allocated DLPRBs
DLPilots
PSD
Time
PSD= (Max_TX_Pwr – CELL_PWR_RED) – 10*log10( 12*#PRBs)
PDCCH
BCH, SCH
PDSCH, PCH
PSD
Frequency
PSD=(Max_TX_Pwr – CELL_PWR_RED) – 10*log10( 12*# PRBs)
Allocated DLPRBs
DLPilots
PSD
Time
PSD= (Max_TX_Pwr – CELL_PWR_RED) – 10*log10( 12*#PRBs)
PDCCH
BCH, SCH
PDSCH, PCH
LNCEL: dlCellPwrRed
0..10dB, default = 0 dB

Power allocations
Channel Cell / User 1 TX Mode TX Diversity Mode MIMO SM Mode
BCCH (PBCH+PDSCH) Cell PSD_0 PSD_MIMO PSD_MIMO
PDCCH User
PSD_0/
PC
PSD_MIMO/
PC
PSD_MIMO/
PC
PCFICH Cell PSD_0 PSD_MIMO PSD_MIMO
PHICH User PSD_0 PSD_MIMO PSD_MIMO
PDSCH User PSD_0 PSD_MIMO PSD_MIMO
RS Cell PSD_0 PSD_0 PSD_0
SYNC Cell PSD_0
PSD_0 /
PSD_MIMO
PSD_0 /
PSD_MIMO
PCH Cell PSD_0 PSD_MIMO PSD_MIMO
At system setup the eNodeB shall claculate the following PSD values:
PSD_0 = (pMax - CELL_PWR_RED) - 10*log10( # PRBs_DL *12)
PSD_MIMO = (pMax - CELL_PWR_RED) - 10*log10( # PRBs_DL *12) - MIMO_COMP
PDCCH power
control can be
enabled by
parameter
Depends if Sync
diversity is
enable/disabled.

DL basic power parameters
Name Object Abbreviation Range Description Default
Cell Power
Reduce
LNCEL dlCellPwrRed 0...10 dB,
step 0.1 dB
CELL_PWR_RED: Sets the power reduction from a antenna
maximum Tx power
0 dB
MIMO
Compensation
LNCEL dlpcMimoComp 0...10 dB,
step 0.1 dB
When TxDiv or 2x2 MIMO SM is used, gain applies in downlink.
Parameter shall be set according to known gain (typically 3dB).
0 dB

Impact of Cell Tx power
•Increasing cell Tx power
will improve DL
performance
•Impact is biggest in noise
limited case (empty
network or isolated cells) LTE max cell power
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 10 20 30 40 50 60 70 80
Phy DL Tput (Mbps)
Cumulative
%
20W
40W
60W
Max Average Max Average Max Average
RSRP (dBm) -72 -88.61 -68 -86.04 -65 -84.12
SINR (dB) 29 23.38 31 23.83 28 23.63
CQI Metric 0 15 11.23 15 11.44 15 11.26
CQI Metric 1 15 11.17 15 11.34 15 11.18
Phy DL Tput (Mbps) 62.34 28.98 70.78 33.31 63.39 34.24
20W 40W 60W
Example results (RL10, 10MHz bw, 3HK trial)

dlpcMimoComp parameter
•Reduces power of all other Channel elements, except
Reference Signal CEs => works like RS boosting
RSRP vs. throughput
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
-130
-128
-126
-124
-122
-120
-118
-116
-114
-112
-110
-108
-106
-104
-102
-100
-98
-96
-94
-92
-90
-88
-86
-84
-82
-80
-78
-75
dBm
Mbps
MIMOcomp 0dB MIMOcomp 3dB
SINR vs. throughput
0
10
20
30
40
50
60
70
-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
dB
Mbps
MIMOcomp 0dB MIMOcomp 3dB

PDCCH power control
• DL Power Control for PDCCH is an additional mechanism interacting with
DL AMC for PDCCH in order to make the signaling as robust as possible
• DL-PC-CCH aims at 1% target BLER but cannot modify AGG assignments
• Main actions performed by DL-PC-CCH
– Power reduction on CCEs with assigned AGG level higher than required (or equal)
– Power boosting on CCEs with assigned AGG level lower than required
– Equal power relocation among all scheduled CCEs
1-CCE
8-CCE 2-CCE
4-CCE
• Macro cell case #1
• Uniform UE distribution
 Very good CCEs (CQI highly above
1% BLER target)
 Bad CCEs (AGG level too high to
meet 1% BLER target)
 If still some power available,
relocate equally among all CCEs

Principles of DL-PC-AMC
• PDCCH Power Control can be enabled/disabled by O&M switch
• Maximum transmit power of the Power Amplifier cannot be exceeded (pMax; O&M)
• Reduction and boosting range is strictly defined and is always considered as the limit for
power level modification
• DL-PC-CCH operates together with DL-AMC-CCH on TTI basis
• DCI messages with more than one CCE (AGG-…>1) have a flat PSD,
thus all CCEs belonging to one scheduled UE are transmitted with the same power
Short
Name
Description
Range/
Step
Default
Value
Parameter
Scope
Remark
enablePcPdcch Enabling/disabling PC for PDCCH.
In case the parameter is disabled, a
flat downlink PSD is used.
true, false true Cell Changing parameter
requires object locking.
pdcchPcBoost Maximum power boost per CCE. 0...10 dB,
step 0.1 dB
4 dB BTS Not modifiable.
pdcchPcRed Maximum power reduction per
CCE.
0...10 dB,
step 0.1 dB
pdcchPcReloc Maximum limit on the equal power
relocation per CCE.
0...10 dB,
step 0.1 dB

General algorithm
OUTPUT_LIST_DL_AMC_CCH
from DL-AMC-CCH
• required AGG levels per UE per DCI format
• assigned AGG levels per UE per DCI format
• pdcchCQI per UE
• calculated TOTAL_NUM_CCEs
(all available CCEs; PHICH&PCFICH considered)
Build the Power Basket
(“free unused” power on PDCCH)
 Count unused power from unscheduled CCEs
 Decrease the power for all UEs with assigned
AGG level equal to the required AGG level to
meet the 1% BLER target and count the amount
to the Power Basket
Increase the power for all UEs with the assigned
AGG level lower than the required AGG level to
meet the 1% BLER target.
Modify the Power Basket according to the amount
of power used for boosting.
If the Power Basket is still not empty, relocate the
excess power equally among all scheduled UEs.
OUTPUT_LIST_DL_PC_CCH
from DL-PC-CCH
• power levels to be applied for all scheduled UEs
…to DL-PHY

Power reduction
• Power reduction is always limited by the threshold (pdcchPcRed)
• CQI_UEi is the output CQI derived based on the assigned AGG level
• CQI_TARGETi is the target CQI for the 1% BLER target for the given DCI format
PWR_REDi = min(pdcchPcRed, 1.96*(CQI_UEi – CQI_TARGETi)) [dB]
CQI_UEi ≥ CQI_TARGETi
This can happen to UEs:
 with the assigned AGG-1 although
the CQI is still much higher than
required for 1% BLER
 with AGG-2, -4 or -8 with the CQI
slightly above 1% BLER target
 with AGG level perfectly matching the
requirement for 1% BLER target
• The factor of 1.96 has been obtained from 4GMax
• The Power Basket PWR_BASKET is correspondingly
modified but the detailed calculation will depend on
the implementation
• Finally the power correction must be stored in
PWR_BASKET += f(AGG-Xi, PWR_REDi)
PSDi = PSD_UE_CTRL – PWR_REDi

Power boosting
• Power boosting is always limited by the threshold (pdcchPcBoost)
• CQI_UEi is the output CQI derived based on the assigned AGG level
• CQI_TARGETi is the target CQI for the 1% BLER target for the given DCI format
PWR_BOOSTi = min(pdcchPcBoost, 1.96*(CQI_TARGETi – CQI_UEi )) [dB]
CQI_UEi ≤ CQI_TARGETi
It can happen if all the following
conditions are true:
 enableLowAgg=true &
 enablePcPdcch=true &
 PDCCH Utilization > pdcchLowAggTh
…then:
 all AGG-8AGG-4 &
 all AGG-4AGG-2
• The factor of 1.96 has been obtained from 4GMax
• The Power Basket PWR_BASKET is correspondingly
modified but the detailed calculation will depend on
the implementation
• Finally the power correction must be stored in
PWR_BASKET –= f(AGG-Xi, PWR_REDi)
PSDi = PSD_UE_CTRL + PWR_BOOSTi
DL-PC-CCH “will take care of” the UEs
which are assigned with too low AGG-
levels (lowering AGG levels cannot be
performed w/o PC for PDCCH enabled).

Power relocation
• Power relocation is always limited by the threshold (pdcchPcReloc) however the total power
increase due to boosting and relocation cannot exceed pdcchPcBoost
PWR_RELOCi = min(pdcchPcReloc, 10*log10(1+PWR_BASKET/(TOTAL_NUM_CCES*CCE_UTILIZATION)))
PSDi = PSD_UE_CTRL + min(pdcchPcBoost, - PWR_REDi + PWR_BOOSTi + PWR_RELOC)
…however it will never happen that the one
and the same CCE is decided to be boosted
and reduced at the same time (TTI).

CQI reporting

Several CQI Reporting Modes have been defined in 3GPP:
•Periodic and Aperiodic CSI (Channel Status Indicator)
•Aperiodic CSI reports are sent on PUSCH only
•Periodic CSI reports can be setn either on PUCCH or PUSCH
•The reporting mode of CSI also depends on DL transmission mode
– Single Stream, Dual Tx (Alamouti), open loop spatial Mux, closed loop spatial mux)
• CQI can be reported the follwing way
– a) Wideband – over whole frequency range (like in UMTS HSDPA)
– b) UE selected sub-band reporting
– c) L3 configured sub-band reporting
 b) and c) needed to support „Downlink Frequency Domain Scheduling - DFDS“
DL Scheduler: CQI Reporting Modes

CQI Reporting
Aperiodic Periodic
PUSCH
PUSCH or PUCCH
Wideband
UE selected
sub-band
L3 configured
sub-band Wideband
UE selected
sub-band
1-2 2-0 2-2 3-0 3-1 1-0 1-1 2-0 2-1
4,6 1,2,3,7 4,6 1,2,3,7 4,5,6 1,2,3,7 4,5,6
1,2,3,7 4,5,6
Rep
Mode
Trans
Mode

Aperiodic Reporting: (on PUSCH only)
•Aperiodic reporting can be enabled/disabled on LNCEL level: cqiAperEnable
•Reporting Mode can be controlled with LNCEL: cqiAperMode
– FBT1 means UE selected sub-band reporting is used
– FBT2 means L3 selected sub-band reporting is used
• eNB can poll CQIs out of UE based on certain timer LNBTS: cqiAperPollT
Periodic Reporting: (on PUCCH or PUSCH [multiplexed with data])
• cqiPerSimulAck controls whether UE need to report CQI simulatneous with HARQ ACK-NACK info
• For combined wideband and sub-band reporting operator can instruct UE how many sub-band reports of a
the bandwidth parts should be included between 2 consecutive wideband CQI reports: cqiPerSbCycK
• cqiPerNb controls the frequency when UE shall deliver the periodic CQI reports
• For transmission modes 3 and 4 UE needs to know where is the position to send Rank Indicator realtive to
CQI report LNCEL: riPerM (default is „1“) defines multiplier for LNCEL: riPerOffset (default is „-1“)
– Current default is „Rank Indicator shall be sent exactely 1 TTI before CQI is sent“
• eNB controls mode of reporting with LNBTS: cqiPerMode (Wideband only or Wideband and sub-band)

• Periodic on PUCCH
– Mode 1-0
 wideband CQI
 rank indicator
• Aperiodic on PUSCH
– Mode 2-0
 aperiodic on PUSCH
 wideband CQI
 one average CQI for M best subbands of size k
– Mode 3-0
 only for first codeword (in case of dual stream)
 wideband CQI
 one CQI for each subband (higher layer configured)
CQI/RI/PMI reporting modes in RL10
System Bandwidth
DL
RB
N
Subband Size k (RBs) M
6 – 7 NA NA
8 – 10 2 1
11 – 26 2 3
27 – 63 3 5
64 – 110 4 6
System Bandwidth Subband Size
DL
RB
N (k)
6 - 7 NA
8 - 10 4
11 - 26 4
27 - 63 6
64 - 110 8
Example: 10 MHz channel bandwidth
(different colours stands for different reported CQI values)
Mode 1-0 Mode 2-0 Mode 3-0
RL10 default config: Mode 1-0 + Mode 3-0

Aperiodic (PUSCH) reporting 2-0 versus 3-0
• Mode 2-0 reports only average CQI over M best UE-selected subbands
– Example: System bandwidth =10 MHz  average CQI over the best 5x3=15 PRBs
reported, no subband info for remaining 35 PRBs
• Mode 3-0 reports the whole band for a set of subbands
System Bandwidth
DL
RB
N
6 – 7 NA NA
8 – 10 2 1
11 – 26 2 3
27 – 63 3 5
64 – 110 4 6
M = 3 best Subbands are selected and an average CQI value is reported
Channel SINR
Subband index 1 2 3 4 5 6 7 8
PRB index 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Best-M scheme
Best-M scheme (2-0)
Full subband CQI (3-0)
DL
RB
N (k)
6 - 7 NA
8 - 10 4
11 - 26 4
27 - 63 6
64 - 110 8

Memory rule for CQI report names
• Reporting Mode x-y:
– x denotes CQI frequency reporting type
 x=1 (wideband)
 x=2 (UE-selected best-M subbands)
 x=3 (eNB-selected subband size, reporting over entire band)
– y denotes Precoding Matrix Indication frequency reporting type
 y=0 (no PMI reported)
 x=1 (one PMI reported, wideband)
 x=2 (multiple PMI reported, subband)
• Rank Indicator is always wideband, i.e., single RI value per report
• Example: Report 3-0 @20MHz system means that full-band CQI reporting using
subband size of 8 PRBs  ROUNDUP(100/8)=13 CQI values are reported. No
PMI is reported.
• PMI reporting only needed with closed-loop MIMO and rank-1 precoding
transmission modes
System Bandwidth
DL
RB
N
6 – 7 NA NA
8 – 10 2 1
11 – 26 2 3
27 – 63 3 5
64 – 110 4 6
Best-M scheme (2-0)
Full subband CQI (3-0)
DL
RB
N (k)
6 - 7 NA
8 - 10 4
11 - 26 4
27 - 63 6
64 - 110 8

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