09 RA47059EN16AGLA0 Capacity Management

Capacity Management Slide 1

NokiaEDU Capacity Management LTE Optimization Principles [FL16A] Module 09

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Capacity Management Slide 2

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Capacity Management Slide 4

Module Objectives • After completing this module, you will be able to:

• Summarize related network and field KPIs • Discuss PDCCH Optimization • Describe PUCCH capacity and related parameters

• Give an overview about PRACH planning and Optimization • Explain the concept of PCH Optimization in LTE • Discuss power saving optimization in LTE

• Summarize capacity features and parameters

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Capacity Management Slide 5

Index -

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Network + Field KPIs Summary KPI targets and reference values PDCCH optimization PUCCH optimization PRACH optimization PCH optimization Power optimization Relevant features and parameters summary

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Capacity Management Slide 6

The Most Important Usage KPIs – Traffic Tput • PDCP mean DL • LTE_5292d Average PDCP Layer Active Cell Throughput DL, kbps

• PDCP mean UL • LTE_5289d Average PDCP Layer Active Cell Throughput UL, kbps • PDCP peak DL

• LTE_291b Maximum PDCP Throughput DL, Kbps • PDCP peak UL

• LTE_288b Maximum PDCP Throughput UL, Kbps

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Capacity Management Slide 7

The Most Important Usage KPIs – Number of Users • Definitions

• Active user = user with at least one DRB established • RRC-connected user = user in RRC-connected mode

• Mean number of active users per cell • LTE_717a Average number of active users per cell • Peak number of active users per cell

• LTE_718a Maximum number of active users per cell • Mean number of RRC-connected users • LTE_805a Average of RRC connected users

• Peak number of RRC-connected users • LTE_806a Maximum of RRC connected users

- Radio Admission Control • LTE_5590c E-UTRAN RRC Connection Setup Failure Ratio per Cause, Rejection from eNB • LTE_5707a E-UTRAN RRC Connection Setup Failure Ratio per Cause Rejection from eNB due to Overload and Lack of Resources • LTE_5104a E-UTRAN HO Preparation Failure Ratio per Cause, intra eNB AC

• LTE_5107a E-UTRAN HO Preparation Failure Ratio per Cause, inter eNB X2 based AC

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Capacity Management Slide 8

The Most Important Usage KPIs – Data Channel Usage Per Cell • PRB usage, PDSCH cell-level • LTE_5276b E-UTRAN average PRB usage per TTI DL

• PRB usage, PUSCH cell-level • LTE_5273b E-UTRAN Average PRB usage per TTI UL

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Capacity Management Slide 9

The Most Important Usage KPIs – CCH Usage • Usage, PDCCH • M8011C61 PDCCH_3_OFDM_SYMBOLS • M8011C60 PDCCH_2_OFDM_SYMBOLS

• M8011C59 PDCCH_1_OFDM_SYMBOL • M8011C39..42 AGG1..8 used PDCCH

• M8011C43..46 AGG1..8 blocked PDCCH • Usage PUCCH • LTE_781a PRB PUCCH distribution Rate (does not identify blocking)

• LTE_5700a E-UTRAN SCell Scheduling Blocking Rate due to Conflicts on PUCCH Format 1bwcs Resources • LTE_5701a E-UTRAN SCell Scheduling Blocking Rate due to Conflicts on PUCCH Format 3 Resources • M8013C67 Number of Signaling Connection Establishment Requests rejected due to lack of PUCCH resources

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Capacity Management Slide 10

The Most Important Usage KPIs – RACH Usage • Usage, RACH LTE_5569a

E-UTRAN RACH Setup Completion Success Rate Identifies ratio of downlink RARs to received preambles

LTE_5670a

E-UTRAN Complete Contention Based RACH Setup Success Rate the number of Msg3 and RA preambles received from a UE during a contention-based RA procedure. Complete RACH Setup Success Rate Ratio of Signaling connection establishments to received contention based preambles.

LTE_1056b

LTE_5820a

Number of non-power limited UEs with RACH success within 1st preamble

LTE_5821a

Number of non-power limited UEs with RACH success after preamble retransmission

LTE_5822a

Total number of UEs with RACH success within 1st preamble

LTE_5823a

Total number of UEs with RACH success after preamble retransmission

LTE_5824a

Number of power limited UEs with RACH success within 1st preamble

LTE_5825a

Number of power limited UEs with RACH success for preamble re-transmission

• M8001C6 RACH_STP_ATT_SMALL_MSG

• M8001C7 RACH_STP_ATT_LARGE_MSG • M8001C286 RACH_STP_ATT_DEDICATED 10

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Capacity Management Slide 11

The Most Important Usage KPIs – PCH Usage • Usage, PCH • No utilization KPI available • LTE_5031b E-UTRAN RRC Paging Discard Ratio

• LTE_5122b E-UTRAN RRC Paging Records

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Capacity Management Slide 12

Index -

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Network + Field KPIs Summary KPI targets and reference values PDCCH optimization PUCCH optimization PRACH optimization PCH optimization Power optimization Relevant features and parameters summary

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Capacity Management Slide 13

KPI Targets • Traffic/user volume • n/a • PDSCH/PUSCH channel usage

• n/a • PDCCH/PUCCH channel usage • No PUCCH blocking should be allowed • Some PDCCH blocking is acceptable (increases delay, FFS)

• RACH usage • Average of 3 preambles per PRACH slot should not be exceeded (higher values are ok in bursts)

• PCH usage • With FSMr2 paging capacity is ~400 S1 paging messages per second. TA splitting (or some other method of reduction of paging load) should take place well in advance before this limit is reached

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Capacity Management Slide 14

Index -

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Network + Field KPIs Summary KPI targets and reference values PDCCH optimization PUCCH optimization PRACH optimization PCH optimization Power optimization Relevant features and parameters summary

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Capacity Management Slide 15

PDCCH Overview - The PDCCH carries the UL & DL scheduling assignments - A PDCCH is transmitted on an aggregation of one 1, 2, 4 or 8 control channel elements (CCE). A CCE consists of 36 REs

- The aggregations of CCEs have a tree structure, where an aggregation consisting of n CCEs starts on position (i mod n), where i is the CCE number - Further restrictions on the aggregations are defined with a Hashing function

pdcchAggDefUE

PDCCH LA UE default aggregation; used, when enableAmcPdcch disabled or no valid CQI exists LNCEL; 1(0), 2 (1), 4 (2), 8 (3); -; 4 (2)

The target error probability for a missed detection of a PDCCH is 10 -2

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Capacity Management Slide 16

DL - L1/L2 control info: PDCCH Resources

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-

The Maximum Number Of OFDM Symbols For PDCCH parameter defines how many OFDM symbols can be used.

-

eNB selects the actual value for each TTI, which is signaled to UE in PCFICH.

-

Range: 1, 2, 3 (BW > 1.4 MHz);

-

Range: 2, 3, 4 (BW = 1.4 MHz)

-

setting: maxNrSymPdcch

-

Usage Based PDCCH Adaptation) allows to maximize PDSCH throughput and reduce PDCCH blocking by adjusting dynamically the number of symbols used for PDCCH

-

Example shows dynamic (ActldPdcch) case for MaximumNumberOfOFDMSymbolsForPDCCH=3 (yellow)

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Capacity Management Slide 17

SSS PSS

Frequency

Physical Layer Downlink Summary DL-Physical Data & Control Channel

PBCH

PCFICH PHICH PDCCH Reference signals PDSCH UE1

PDSCH UE2 Time 17

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Capacity Management Slide 18

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

• Macro cell case #1 • Uniform UE distribution

4-CCE

8-CCE

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2-CCE

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Capacity Management Slide 19

CQI-to-Aggregation Mapping unit CQI from DL-AMC/DL-OLQC

CQI filtering/processing

ULS_IINPUT_LIST = { UE-1, Tag, USS, Prio-X; UE-2, Tag, USS, Prio-Y; …; UE-k: ...; }

Filtered, compensated and shifted CQI All DCI formats… 1 1a

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: ...; }

CQI-to-Aggregation Mapping • 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 = { UE-1: pdcchCQI, AGG-DCI0, AGG-DCI1, …; UE-2: pdcchCQI, AGG-DCI0, AGG-DCI1, …; …; UE-k: ...;}

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• 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.

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Capacity Management Slide 20

CQI-to-Aggregation Mapping unit

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. CQI = 0.51*SINR + 5.3 - 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. SFsmallDCI = 10*log10(DCI_size/45) SFlargeDCI = 10*log10(DCI_size/60) Mapping table for 45/60 bits payload composed based on CQI-to-SINR formula (4GMax)

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Capacity Management Slide 21

CQI-to-Aggregation Mapping unit

pdcchAggDefUE

rdPdcchAggTables

PDCCH LA UE default aggregation; LNCEL; 1(0), 2(1), 4(2), 8(3); 4(2)

- 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 OLLA PDCCH is disabled, see below).

Mapping table for 45/60 bits payload composed based on CQI-to-SINR formula (4GMax)

- If PDCCH AMC is disabled or CQI is outdated, pdcchAggDefUe will be applied to all DCI formats of all UEs.

CQI = 0.51*SINR + 5.3 SFsmallDCI = 10*log10(DCI_size/45)

SFlargeDCI = 10*log10(DCI_size/60)

pdcchCqiShift

LNCEL; -10…10;0.1; 0

Full rdPdcchAggTables for all available DCI formats (10MHz system bandwidth)

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Capacity Management Slide 22

OLLA for PDCCH - Motivation • PDCCH carries information about the resources assignments for both Uplink (UL) and Downlink (DL) data channels. Downlink scheduling grant (MCS, PRBs, ..)

TTI n

TTI n

PDCCH

TTI n+x

PDSCH e-NB

Scheduling request

Uplink scheduling grant (MCS, PRBs, ..)

UE

e-NB TTI n+y

PUCCH/PUSCH

PDCCH PUSCH

Data

UE

Data

• If a PDCCH payload is missed the User Equipment (UE) cannot know whether it has been scheduled and on which time/frequency resources.

TTI n

?

TTI n

PDCCH

PUCCH/PUSCH

TTI n+x

PDCCH

PDSCH UE

e-NB

e-NB TTI n+y

?

PUSCH

UE

Waste of Resources! 22

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Capacity Management Slide 23

OLLA for PDCCH – Principle The PDCCH OLLA can be based on the PDSCH OLLA as follows:

Offset_PDCCH = deltaCQI + pdcchCqiShift,

deltaCQI from OLQC is used to control the PDSCH and PDCCH inner loop link (ILLA) adaptation. It is the PDSCH OLQC offset available and calculated based on the Ack/Nack/DTX feedback from previous PDSCH transmission

and pdcchCqiShift is a term needed to compensate for the difference in BLER target for the PDSCH (e.g. 10%) and PDCCH (e.g. 1%).

pdcchCqiShift is in use to fine tune the PDCCH BLER The value is controlled statically by O&M: pdcchCqiShift or dynamically by the feature. In the latter case it’s computation is based on a similar algorithm as used for PDSCH OLLA and the target BLER PDCCH is O&M defined by pdcchHarqTargetBler

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Capacity Management Slide 24

PDCCH Blocking • PDCCH can be allocated in blocks of 1, 2, 4, 8 CCEs • Full PDCCH capacity cannot be typically used • Example: 10MHz has max 43 CCEs/TTI, however in one TTI it is not possible to allocate the combination 5*8CCE + 1*2CCE + 1*1CCE = 43CCEs (due to 3GPP PDCCH limitations) • PDCCH blocking can occur which may result in handover delays, data tput reduction etc • Recommended: load-based PDCCH allocation • PDCCH blocking KPIs need to be monitored

LTE_772a LTE_773a LTE_774a LTE_775a LTE_776a LTE_777a LTE_778a LTE_779a

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AGG1 utilization distribution rate AGG2 utilization distribution rate AGG4 utilization distribution rate AGG8 utilization distribution rate AGG1 blocked distribution rate AGG2 blocked distribution rate AGG4 blocked distribution rate AGG8 blocked distribution rate

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Capacity Management Slide 25

PDCCH Blocking Example from Operator X, RL20 • One site examined as an example • AGG4 most used, AGG8 second most – High AGG8 PDCCH block ratio up to 14%  lot of users in bad RF

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Capacity Management Slide 26

PDCCH Blocking – Impact of PUSCH Proactive Scheduling, RL30 Field Test • PUSCH proactive scheduling increases PDCCH usage • Pro-active scheduling has low priority, hence it won‘t block „real“ traffic • Drawback: three OFDM symbols are scheduled more often  less room for PDSCH. • Drawback: cannot tell real blocking from dummy grant blocking • Benefit: reduced latency

PDCCH 3 PDCCH OFDM Blocking Avg. CFI Symbol Rate Rate

UL RB Usage

PDCCH Usage [RB]

ilReacTimerUl=1500ms 3.50%

33.20%

59073554 3.90%

45%

2.1

ilReacTimerUl=0ms

3.00%

3.40%

7533658

8%

1.3

Delta

0.60%

29.80%

51539896 3.80%

36.10%

0.7

37% Reduction

DL tput 5.2% improvement

DL RB Usage

Item

Improvement, percents

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90% 87% Reduction Reduction

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97% Reduction

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Capacity Management Slide 27

PDCCH Blocking – How To Reduce It? • Some PDCCH blocking is acceptable as it kind of means that PDCCH is efficiently utilized • NOTE: pro-active scheduling results in „virtual blocking“ • How much is acceptable? • If UE scheduling is blocked, then it will be scheduled in a later TTI, so basically blocking just increases delay • If AGG8 blocking is high, it means that cell has RF problems • Fixing it: • Check that load adaptive PDCCH size is used - true • Off-loading users to neighboring cells by shrinking cell size by physical RF tuning, or by using handover and idle mode cell reselection offsets • Load balancing between layers • Increase the network capacity, add sectors, indoor BTSs, etc • PDCCH CQI shift value of -5 is current Golden SCF default, could be changed? Reduce pro-active scheduling timers? • Somehow reduce PDCCH load: ghost RARs, paging, high reTx rate, PDCCH orders

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Capacity Management Slide 28

Index -

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Network + Field KPIs Summary KPI targets and reference values PDCCH optimization PUCCH optimization PRACH optimization PCH optimization Power optimization Relevant features and parameters summary

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Capacity Management Slide 29

PUCCH Dimensioning • Scope: Dimensioning of the PUCCH region (how many RBs) to avoid excessive overheads - PUCCH is used to transfer Uplink Control Information (UCI) when the PUSCH is not in use through different PUCCH formats:

•

• •

PUCCH is allocated RBs at the 2 edges of the channel BW – To avoid fragmenting PUSCH RBs – To provide frequency diversity PUCCH always occupies 2 RBs distributed across the two time slots of a subframe Each PUCCH transmission uses 1 RB on each side of the channel bandwidth

Note: RB in here corresponds to 3GPP definition of 12 subcarriers x 1 slot

Transmission from a single UE

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Capacity Management Slide 30

PUCCH Structure -

The logical split between the PUCCH formats is the following:

-

1. Resources allocated for format 2/2a/2b/3 i.e. CQI • Number of resource blocks (RBs) defined by the parameter nCqiRb

•

The Parameter is semistatic allocated (and broadcasted)

•

Depends on the number of RRC connected UEs

•

Allocated on the outermost RBs (edge of the

LNCEL: nCqiRb reserved RBs per slot for PUCCH formats 2/2a/2b/3 1..98; 1 Default ; 2

APUCCH: assignedNPucchF3Prbs assignedNPucchF3Prbs PRBs for HARQ Format 3 used in PUCCH allocation 0..2 Default: 0

UL bandwidth) -

2. Resources allocated for format 1/1a/1b Semistatic allocation for Scheduling Request Information (SRI) • For SRI the parameter n1pucchAn is used •

to calculate the number of RBs (the parameter is broadcasted)

-

• •

It depends on the number of RRC connected UEs Dynamic allocation for ACK/NACK

•

The number of RBs for ACK/NACK depends

on the total number of scheduled UEs 3. Mixed formats 1 & 2 •

Used for small bandwidth (e.g. 1.4 MHz)

•

pucchNanCS parameter used to calculated the number

of RBs for mixed formats

LNCEL: n1PucchAn Offset to calculate ACK/NACK resources from PDCCH CCE 0..2047; 1 Default; 36

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(1) The maximum value of nCqiRb depends on ulChBw (in PRB) - if ulChBw is set to '1.4 MHz', nCqiRb must be configured to 1 - if ulChBw is set to '3 MHz', nCqiRb must be configured to 1 - if ulChBw is set to '5 MHz', nCqiRb is restricted to 1..25 - if ulChBw is set to '10 MHz', nCqiRb is restricted to 1..50 - if ulChBw is set to '15 MHz', nCqiRb is restricted to 1..75 - if ulChBw is set to '20 MHz', nCqiRb is not limited

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Capacity Management Slide 31

PUCCH UEs Multiplexing in One Resource Block -

-

For formats 2/2a/2b UEs are separated using CDM (code division multiplexing) inside the RB •

CDM is using the cyclic shift of the length 12 CAZAC sequence

•

The number of cyclic shifts is given by the parameter deltaPucchShift

•

deltaPucchShift = 1,2,3 indicating 12, 6 or 4 shifts

•

With 12 shifts 12 UEs could be multiplexed in one RB, with 6 shifts 6 UEs could be multiplexed and so on

•

It is recommended that no more than 6 UEs are multiplexed per RB (even if 12 are possible) to minimize interference

For formats 1/1a/1b on top of CDM also a block wise spreading with an orthogonal cover sequence is applied

•

3 orthogonal codes are used so the multiplexing capacity is 3 times increased

•

If 6 cyclic shifts and 3 orthogonal codes are used then the multiplexing capacity is 6*3= 18 UEs per RB

PUCCH formats

Number of Bits

Control type

PUCCH Format 1

Scheduling request

PUCCH Format 1a

1-bit ACK/NACK

PUCCH Format 1b

2-bit ACK/NACK

PUCCH Format 2

CQI

1 2

36, *18, 12 36, *18, 12

20

36, *18, 12 12, *6, 4 12,* 6, 4

PUCCH Format 2a

CQI + 1-bit ACK/NACK

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PUCCH Format 2b

CQI + 2-bit ACK/NACK

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12, *6, 4

deltaPucchShift delta cyclic shift for PUCCH formats 1/1a/1b LNCEL; 1..3; 1; 2 (i.e. 6 cyclic shifts)

*typical value

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Multiplexing Capacity (UE/RB)

ON/OFF keying

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Capacity Management Slide 32

Number of Resource Blocks for formats 2/2a/2b •

The number of RBs required for formats 2/2a/2b

•

depends on the number of RRC connected UEs

•

Defined by maxNumRrc parameter

•

Example configuration 2: •

CQI periodicity is 20 ms -> there are 20 TTIs transporting CQIs

•

Assuming 6 UEs multiplexed per TTI and per RB then there are 6*20= 120 UEs (per 20 TTIs/ per RB)

•

Number of RRC connected UEs maxNumRrc

Number of RBs nCqiRb

CQI Periodicity cqiPerNp

1.

840 (1680)

14

10 ms

2.

840 (1680)

7

20 ms

3.

768 (1536)

4

32 ms

4.

420 (840)

7

10 ms

5.

480 (960)

4

20 ms

6.

384 (768)

2

32 ms

7.

240 (480)

2

20 ms

8.

120 (240)

2

10 ms

9.

192 (384)

1

32 ms

10.

120 (240)

1

20 ms

11.

60 (120)

1

10 ms

So to support 840 RRC connected UEs we need:

840/120 = 7 RBs •

Please note that only 6 cyclic shifts are used in order

•

to avoid interference (even if 12 cyclic shifts possible) •

Con fig

With 12 cyclic shifts 12 UEs are multiplexed per TTI

so the capacity is doubled (the number are in the brackets in the table)

maxNumRrc Max. number of Use in the cell with established RRC connection LNCEL; 0..840; 1; 240 (*420 for 20 MHz bandwidth)

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cqiPerNp CQI periodicity LNCEL; 2ms (2), 5ms (5), 10ms (10), 20ms (20), 40ms (40), 80ms (80) default: 40ms(40)

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Number of RBs allocated for formats 2/2a/2b example

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Capacity Management Slide 33

Number of Resource Blocks for formats 1/1a/1b – SRI -

The number of RBs for SRI depends on:

-

parameter n1PucchAn (Ack/Nack offset relative to the

deltaPucchShift

n1PucchAn

Number of RBs for SRI

1

36

1

1

72

2

1

108

3

1

144

4

…

…

…

1

360

10

18 UEs could be multiplexed per TTI and per RB

2

18

1

So there are 20*18 = 360 UEs per 20 ms

2

36

2

Assuming that maximum number of RRC connections

2

54

3

2

72

4

…

…

…

2

180

10

3

12

1

…

…

…

3

120

10

Lowest CCE index of the associated DL scheduling PDCCH) Number of cyclic shifts deltaPucchShift

-

n1PucchAn * deltaPucch Shift Number _ PUCCH _ RBs _ SRI  roundup( ) 3 *12

Example: Assuming that deltaPucchShift = 2 and the periodicity of SRI is 20 ms (cellSrPeriod parameter) then

maxNumRrc is 840 then we need roundup(840/360) = 3 RBs for SRI

So the offset for Ack/Nack -> n1PucchAn = 54

cellSrPeriod SRI repetition period LNCEL; 5ms(0), 10ms(1), 20ms(2), 40ms(3), 80ms(4); 20ms(2)

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Capacity Management Slide 34

Number of Resource Blocks for formats 1/1a/1b – dynamic ACK/NACK - The number of resource blocks for dynamic ACK/NACK is not fixed but it depends on the amount of scheduled UEs - For the dimensioning of PUCCH resources for ACK/NACK the total number of CCE (control channel elements) available for PDCCH are considered :

Number _ PUCCH _ RBs _ ACK / NACK  roundup(

- The total number of CCEs depends on the system bandwidth:

TotalNumCCE * deltaPucch Shift ) 3 *12

- Example: Assume that bandwidth is 10MHz and the deltaPucchShift is 2 then the number of resource blocks for dynamic ACK/NACK is:

43 * 2 Number _ PUCCH _ RBs _ ACK / NACK  roundup( )3 3 *12

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Bandwidth

Total Number of CCEs

5 MHz

21

10 MHz

43

15 MHz

65

20 MHz

87

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Capacity Management Slide 35

Number of RBs for PUCCH – total

- The total number of RBs required for PUCCH is the sum of RBs required for CQI, for SRI and dynamic ACK/NACK:

 TotalNumCCE  n1PucchAn * deltaPucch Shift  Number _ PUCCH _ RBs  nCqiRb  roundup  3 *12  

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Capacity Management Slide 36

Carrier aggregation for multi-carrier eNode Bs PUCCH implications

General comment on 2CC CA and PUCCH: Multi-cell ACK/NACK sent via PUCCH (on PCELL)is handled via special message: PUCCH format 1b with channel selection – standardized specifically for Carrier Aggregation for the cases where there is a need to send up to 4 bits of HARQ information (2 per each cell due to MIMO – one bit for each transport block) LTE1562: PUCCH 1b CS resources in the primary cell are statically split 50/50 between SCell A and SCell B: • UEs configured with SCell A got only odd numbered PUCCH 1b CS resources

• UEs configured with SCell B got only even-numbered PUCCH 1b CS resources

For 3 CC CA PUCCH format 3 must be used. These blocks are located within the area defined by nCQIrb, and the number of resource blocks by assignedNPucchF3Prbs. Therefore nCQIrb must be increased by assignedNPucchF3Prbs amount. APUCCH: assignedNPucchF3Prbs assignedNPucchF3Prbs PRBs for HARQ Format 3 used in PUCCH allocation 0..2 Default: 0

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LTE1562

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Capacity Management Slide 37

Carrier Aggregation • PUCCH resources are adjusted at once if only CAREL object is created under given LNCEL what implies that this cell could play a role of a primary cell in the Carrier Aggregation • Note that if PUCCH size is extended, amount of PRBs to be used for PUSCH will be decreased. Consequently, UL cell capacity will be compromised.

• The cell playing a role of secondary one is not affected unless it plays also a role of the primary cell (symmetrical relation between PCell and SCell was created).

Note: maxNumCaConfUeDc maxNumCaConfUe3c parameters do not affect the amount of PUCCH resources configured to convey multi-cell ACK/NACK and taken out from SR resources

It is likely the case that UL capacity will be compromised in contrast to nonCA case because n1PucchAn has to be equal to at least 72 for regular CA deployments

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Capacity Management Slide 38

Automatic PUCCH Capacity Optimization (LTE1808) Feature Overview • PUCCH capacity optimization automatically adjusts the PUCCH resource size according to the actual traffic load in the LTE cell. • It evaluates cell’s performance counters for a defined period of time and determines adjustment needed to Admission control parameters (i.e., maxNumRRC, maxNumRRCEmergency, maxNumActDrb, maxNumActUE and maxNumQci1Drb) as per traffic load in the cell. • Based on the adjustment to Admission control parameters, it does the adaptation of PUCCH size adjusting the values for the parameters: nCqiRb and n1PucchAn. Additionally, PUCCH Periodicity parameters (cellSrPeriod and cqiPerNp) are also adjusted. • In order to ensure that PUCCH resources do not overlap with PRACH resources, changes in PUCCH size would trigger check for consistency of PRACH assignment, i.e., check/recalculation of PRACH parameters. • The finally proposed changes are saved to a plan and provisioned to the network automatically eventually increasing efficient usage of resources and efficiency of the network.

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Capacity Management Slide 39

LTE1130: Dynamic PUCCH allocation Before & after

LTE1808 Automatic PUCCH Capacity optimization (phased out in FL16A/TL16A) •

•

•

39

PUCCH resource allocation is automatically adjusted on cell individual level based on real load ongoing in that cell (by using information from at least one previous day) Irrespectively of cell load conditions values of CQI and SR periodicities are always the same for all UEs NetAct feature

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LTE1130 Dynamic PUCCH allocation •

• •

Simplified configuration • Less parameters to configure • Less consistency checks Dynamic switching between CQI periodicity:40, 80 ms Dynamic switching between UL Scheduling Request periodicity: 10 ms, 20 ms, 40 ms

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Capacity Management Slide 40

Flexible Uplink Bandwidth (LTE786) (LTE825)

LNCEL: blankedPucch (Blanked PUCCH resources) Range:0.. 60 ;

Purpose of the feature is to define an area at the borders of uplink band where PUSCH nor PUCCH are not allocated to any UE •

Achieved by increasing the bandwidth allocated to PUCCH, and not using the resources situated at spectrum edge.

•

LTE transmission bandwidth thus reduced, leaving blanked areas at bandwidth edge.

•

Blanked areas serve as a guard band for reducing out of band emissions

default: 0 (feature off)

WCDMA 5MHz

LTE 5 MHz

Deployment possible with narrower spacing LNCEL: selectOuterPuschRegion Target UL outer scheduling region

0 1 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940414243444546474849 None (0), UpperEdge (1), LowerEdge (2) Default: None (0)

Blanked area

PUCCH area

PUSCH/ PRACH

PUSCH resources

LTE786 modifies the receiver at the eNodeB. The blanked PUCCH PRBs are not received, therefore they do not influence the received SINR. This means that the blanked resources do not contribute to the PUCCH RSSI nor SINR statistics, the measurements of the PUSCH RSSI and SINR are performed on the reduced amount of PRBs

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Allows for leaving border uplink PRBs unused Based on standardized possibility to freely determine the size of the PUCCH area allocated for PUCCH Format 2.x These resources are used for CQI transmission. LTE786 in the first step allocates more PRBs for PUCCH, and then modifies the algorithm allocating PUCCH CQI with an offset effectively preventing the border PRBs from being used. The number of blanked PRBs is determined by blankedPucch. The feature affects both sides of the spectrum Only symmetrical configurations possible, LTE835 uplink outer region scheduling allows upper or lower edge to be scheduled for PUSCH or PRACH Any modification of PUCCH size affects the remaining PUSCH area The operator has to assure sufficient PUCCH capacity with PUCCH blanking activated PUCCH planning has to consider only actually used PUCCH Format 2.x resources

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Capacity Management Slide 41

Example configuration (uplink bandwidth 10 MHz, 50PRBs) ulChBw = 10 MHz

No PUCCH blanking

PUCCH Format 1.x area

Frequency (PRBs)

0 1 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940414243444546474849

Total PUSCH area: 40 PRBs

0 2 4 6 8 1 3 5 7 9

Total PUCCH area: 2x5PRB

nCqiRb = 4

9 7 5 3 1 8 6 4 2 0

With PUCCH blanking

Area reserved with nCqiRb

PUCCH Format 2.x allocations starting from PUCCH allocation region 16 (PRB #8)

nCqiRb = 20 blankedPucch = 16

Actual blanked area: 2x8PRB

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 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Total PUSCH area: 24 PRBs

0 2 4 6 8 10 12 14 16 18 20 22 24 1 3 5 7 9 11 13 15 17 19 21 23 25

Blanked zone

41

Total PUCCH area: 2x5PRB

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25 23 21 19 17 15 13 11 9 7 5 3 1 0

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Capacity Management Slide 42

LTE1059: Uplink multi-cluster scheduling Resource allocation type 1 • Resource allocation type 1 requires additional bit “Resource Allocation Type” set to 1 which needs to be added to DCI format 0 • Additionally addressing of two clusters requires additional bit compared to single-cluster allocation. Frequency hopping flag is used as a missing bit, therefore frequency hopping on PUSCH can’t be applied together with UL multi-cluster scheduling

• With resource allocation type 1, allocation of resources is done by means of RBGs (Resource Block Groups) like in downlink. Size of RBG depends on system bandwidth • 2-3-5 rule for resource allocation still needs to be obeyed, and additionally RBGs which are partly allocated by PUCCH or PUSCH mask can’t be considered for uplink scheduling

20MHz bandwidth 0

99

PRBs RBGs

x

0

x x

1

2

3

4

5

6

7

8

9

10

11

12

x x PUSCH MASK (BLANKED PRBs)

13

14

15

16

17

18

19

x

20

21

22

23

24

Only those RBGs can be used for UL scheduling due to mentioned rules

For 20MHz: 1RBG = 4PRBs

UEs only from release 10 and above can support multi-cluster scheduling

multiClusterPUSCH-WithinCC-r10 is set to supported nonContiguousUL-RA-WithinCC-Info-r10 is set to supported 42

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With resource allocation type 1 it is possible to allocate resources from 2 PUSCH areas to one UE, therefore in case PUSCH is divided into more areas, the two areas with highest number of PRBs will be selected for resource allocation All parameters which define a certain PRB allocation size like:

Minimum PRB allocation (LNCEL:redBwMinRbUl, LNCEL:ulsMinRbPerUe, LNCEL:ulsMinTbs in conjunction with MCS) Maximum PRB allocation (LNCEL:redBwMaxRbUl, LNBTS:axNumPrbSr, LNBTS:maxNumPrbSr) Initial PRB allocation (LNCEL:iniPrbsUl) have to be adapted to granularity of the RBG size Parameters which determine lower limit or initial PRB allocation will be rounded up Parameters which determine upper limit will be rounded down but to value not smaller than 1 RBG.

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Capacity Management Slide 43

LTE1059: Uplink multi-cluster scheduling Checking BLER target • UE must have enough power to be scheduled in multi-cluster mode so the BLER target will be fulfilled. • Following equation is used to check if UE can be scheduled in multi-cluster mode: Power difference in terms of different number of allocated PRBs between transmission with PHR and current transmission

PHR(t PHR )  10 log10 (

M PHR (t PHR ) )  MPRPHR (t PHR )  MPRPUSCH _ Allocation(t )  5 M PUSCH _ Allocation(t )

Normalized power

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Additional power needed for multi-cluster scheduling

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Hardcoded multicluster scheduling threshold

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Capacity Management Slide 44

PUCCH Blocking - If there is not enough resources to allocate CQI/SR PUCCH resources to a new user, admission control will reject the user • LTE_5218d Total E-UTRAN RRC Connection Setup Success Ratio • LTE_5707a E-UTRAN RRC Connection Setup Failure Ratio per Cause Rejection from eNB due to Overload and Lack of Resources

• LTE_5104a E-UTRAN HO Preparation Failure Ratio per Cause, intra eNB AC • LTE_5107a E-UTRAN HO Preparation Failure Ratio per Cause, inter eNB X2 based AC - The solution is to increase PUCCH region size - However, PUCCH region should be aligned with the number of allowed RRC connected users otherwise PUSCH PRBs are reduced needlessly

• From FL15a some useful new counters

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M8011C166

PUCCH_BLOCK_RATE_FORMT_1BWCS

M8011C167

PUCCH_BLOCK_RATE_FORMT_3

M8013C67

SIGN_CONN_ESTAB_FAIL_PUCCH

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SCell scheduling blocking rate due to conflicts on PUCCH format 1bwcs resources SCell scheduling blocking rate due to conflicts on PUCCH format 3 resources Number of Signaling Connection Establishment Requests rejected due to lack of PUCCH resources

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Capacity Management Slide 45

PUCCH Configuration – Parameters •The following parameter are deployed for PUCCH configuration (10 MHz). Parameters nCqiRb cqiperNp

Range 1...98

2ms (0), 5ms (1), Periodicity of periodic CQI / PMI feedback on PUCCH or 10ms (2), 20ms (3) PUSCH

n1pucchAn

10...2047

deltapucchshift

1…3

cellSrPeriod

Offset to decide the number of resources reserved for SRI (and A/N from persistent PDSCH scheduling in later releases). Maximum number of cyclic shifts allowed for Formats 1/1a/1b

5ms (0), 10ms (1), Scheduling Request periodicity in the cell. The 20ms (2), 40ms recommendation is to have one scheduling request (SR) (3), 80ms (4) configured per frame.

prachFreqOff

0...94, step 1

actLdPdcch

false (0), true (1)

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Description Number of PRBs dedicated to Formats 2.x

First physical resource block available for PRACH in the UL system frequency band. Roundup [PUCCH resources/2]. Must not overlap with PUCCH. Activate or deactivate the load adaptive number of PDCCH symbols in a cell. The actual OFDM symbol amount used for PDCCH in a TTI is dynamically selected from one up to maximum allowed number of PDCCH symbols (maxNrSymPdcch = 3).

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36 2

20 ms 3

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Capacity Management Slide 46

Periodic Rank Indicator (RI) – Parameters •The periodic Rank Indicator (RI) reporting on PUCCH needs to be aligned with a CQI reporting instance in order to allocate only 1 Format 2.x resource for a single UE per cqiPerNp. •Rank Indication periodicity = cqiPerNp * riPerM = 40 ms * 2 = 80ms Parameters

Range

riEnable

false (0), true (1)

riPerM

riPerOffset

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Recommendation 10MHz

Description

Determines whether RI reporting is enabled (true) or not (false).

true

Multiplier M for defining periodic RI feedback reporting period. The parameter defines the offset for the periodic Rank Indicator reporting instance in relation to the CQI reporting subframe. If, for example, subframe 5 is chosen for CQI reporting and riPerOffset is -1, then 1 (0), 2 (1) subframe 4 is chosen for the RI report. In case riPerM is set to value 1 than riPerOffset must be set to -1. In case riPerM is set to value 2 than riPerOffset must be set to 0. In case riEnable is set to 'true' and additionally riPerM is set to 1, cqiPerNp cannot be set to 1 (5ms)

2

Time offset for periodic CQI/PMI reporting for defining the periodic RI reporting instance. The parameter defines the offset for periodic Rank Indicator reporting instance. The offset tells the time shift for the periodic CQI/PMI reporting instance. The range of the offset depends on the periodicity (cqiPerNp) of periodic CQI/PMI reporting

0

-1...0

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Capacity Management Slide 47

Radio Admission Control – Parameters •RAC thresholds for the maximum number of RRC connected users and the active (DRB) users in a cell should be aligned according to the configured PUCCH capacity. Range

maxNumRrc

The number of RRC-connections established in the cell cannot exceed maxNumRrc. RAC shall always be invoked for the admission of SRB1 at RRC Connection Setup. An RRC connection is considered as established if the SRB1 has been admitted and successfully configured. 0..1500 Maximum number of RRC connections (maxNumRrc) is to be set to a higher value (or equal) than maximum number of active UEs in the cell: maxNumActUE + max [addAUeRrHo, addAUeTcHo]