RF TroubleShooting Guideline LA1.1

8/13/2019 RF TroubleShooting Guideline LA1.1

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RF Troubleshooting Guideline LA1.1

Document number: LTE/IRC/APP/032278Document issue: V01.03 / ENDocument status: Approved Standard

Data classification: InternalDate:09/Sep/2010

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RF Troubleshooting Guideline LA1.1 LTE Unit/ TIS-CEC/NPE


LTE/IRC/APP/032278 V01.03 / EN Approved Standard 09/Sep/2010 Page 2/38

1INTRODUCTION

The main interest of the document is to highlight the most used and know workaroundidentified during LA1.1

1.1SCOPE

The document covers the troubleshoot hints for the main RF features of Alcatel-Lucent LTE

release LA1.1

The procedures detailed in this document can be used to avoid long time debugging and

loose time during problems already face in the field.

1.2AUDIENCE FOR THIS DOCUMENT

The audience of this document is typically involved in following activities:

Radio Network Design

Radio Network Optimization

Trials

2PUBLICATION HISTORY

Version.Ed/Language

Date Status NameReason of changes / shortdescription of significant

changes to previous edition

01.01/EN 27/May/2010 Draft Sequeira Sergio Creation

01.02/EN 10/Jun/2010Approved

preliminary

Jorge Santos

Ricardo Costa

Eman Moshneb

Reading Cycle Completed (DR4Step)

01.03/EN 09/Sep/2010Approvedstandard

Herv JulienMAJCHER

DR.5 milestone


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TABLE OF CONTENTS

1 INTRODUCTION...........................................................................................................................21.1SCOPE...........................................................................................................................................2 1.2AUDIENCE FOR THIS DOCUMENT ......................................................................................................22 PUBLICATION HISTORY .............................................................................................................23 REFERENCE DOCUMENTS ........................................................................................................74 WIPS .............................................................................................................................................7

4.1WIPSRECOMMENDATIONS .............................................................................................................7 5 LLDM MASK ................................................................................................................................ .9

5.1LOAD MASK....................................................................................................................................9 5.1.1 Short Description .................................................................................................................95.1.2 Proposed Tests....................................................................................................................9

6 ACCESSIBIL ITY .........................................................................................................................116.1SLEEPING CELL ............................................................................................................................11

6.1.1 Short description................................................................................................................116.1.2 Issue Description ...............................................................................................................126.1.3 Propose steps ....................................................................................................................126.1.4 Workaround .......................................................................................................................13

6.2LAZY CELL ...................................................................................................................................14 6.2.1 Short description................................................................................................................146.2.2 Issue description................................................................................................................146.2.3 Propose steps ....................................................................................................................156.2.4 Workaround .......................................................................................................................15

7 MOBILITY....................................................................................................................................167.1RRCCONNECTION REESTABLISHMENT REJECT .............................................................................16

7.1.1 Short description................................................................................................................167.1.2 Issue description................................................................................................................177.1.2.1 RRC Connection Reestablishment:.........................................................177.1.2.2 Tracking Area Update: .......................................................................177.1.3 Workaround .......................................................................................................................18

7.2TCPACKFREQUENCY MODIFICATION ..............................................................................................18


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7.2.1 Short description................................................................................................................187.2.2 Issue description................................................................................................................187.2.3 Workaround .......................................................................................................................197.2.4 Important Notes /Comments: .............................................................................................21

8 STATIC TRANSPORT FIBER DELAY LENGHT........................................................................228.1FIBER DELAY LENGTH CONFIGURATION ..........................................................................................22

8.1.1 Short description................................................................................................................228.1.2 Issue Description ...............................................................................................................228.1.3 CTC Examples...................................................................................................................228.1.3.1 Comments: ....................................................................................238.1.3.2 Comments: ....................................................................................23

9 MULTI UE....................................................................................................................................239.1UNFAIR ULTHROUGHPUT SHARING ...............................................................................................23

9.1.1 Short description................................................................................................................239.1.2 Propose steps ....................................................................................................................239.1.3 Issue Description ...............................................................................................................249.1.4 Workaround .......................................................................................................................249.1.5 MU parameter setting.........................................................................................................249.1.5.1 UL Parameters ................................................................................249.1.5.2 DL Parameters ................................................................................25

10 NEIGHBOURS PLANNING AND CELL ID PLANNING ...........................................................2510.1NEIGHBORS PLANNING................................................................................................................25

10.1.1 Short description..............................................................................................................2510.2CELL IDPLANNING .....................................................................................................................26

10.2.1 Short description..............................................................................................................2610.2.1.1 Comments: ....................................................................................27

10.3RSRPCRITERIA.........................................................................................................................27 10.3.1 Short description..............................................................................................................2710.3.1.1 Comments: ....................................................................................28

10.4DISTANCE CRITERIA....................................................................................................................28 10.4.1 Short description..............................................................................................................2810.4.1.1 Comments: ....................................................................................28

11 ANTENNA POSITIONING.........................................................................................................2911.1.1.1 Comments: ....................................................................................30


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LIST OF FIGURES

Figure 4.1-1: WIPS parameter changes ............................................................................................................ 8Figure 4.1-2: WIPS work order export ............................................................................................................. 9Figure 5.1-1: Log Mask Setting Dialog ............................................................................................................ 10Figure 5.1-2: CH1 MASK Load Information ..................................................................................................... 11Figure 6.1-1: RRC Connection scenario call flow........................................................................................... 12Figure 6.1-2: T300 expire .............................................................................................................................. 13Figure 6.2-1: MAC RA Problem ....................................................................................................................... 14Figure 6.2-2: RRC connection establishment procedure............................................................................... 15Figure 7.1-1: RRC Connection ReestablishmentReject.................................................................................. 16Figure 7.1-2: No data throughput during HO phase....................................................................................... 18Figure 7.2-1: TSHARK - UE Hardware Interface ID ......................................................................................... 19Figure 7.2-2: TCPoptimizer Edit Registry .................................................................................................... 20Figure 7.2-3: TCPoptimizer Add DWORD ..................................................................................................... 20Figure 7.2-4: TCPoptimizer Modify Value.................................................................................................... 21Figure 8.1-1: Cell 50 in Site 16 (Expo Axis)................................................................................................... 22Figure 8.1-2: Cell 198 in Site 66 (CTC Puxi Business Hall)............................................................................. 23Figure 10.2-1: Cell ID Planning MOD 3 and MOD 6 matrix............................................................................. 27Figure 10.4-1: Sol3 Antenna Ports ................................................................................................................. 29Figure 10.4-2: Antenna Distance Separation /Positioning ............................................................................. 29Figure 10.4-3: DL Traffic Impact ................................................................................................................... 30Figure 12.1-1: LTE Cluster ............................................................................................................................. 31


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LIST OF TABLES

Table 9-1: Unfair Throughput ........................................................................................................................ 24Table 9-2: Fair Throughput ............................................................................................................................ 24Table 12-1: All modes parameters change.................................................................................................... 37

3REFERENCE DOCUMENTS

Ref. Document Number Title

[1] PPP/DDD/CCC/NNNNGPS US site team

http://nwswww.ih.lucent.com/~lte-gps/

[2] PPP/DDD/CCC/NNNN

LTE OUTDOOR RF DESIGN GUIDELINE (Advanced RFCompetence Center)

https://wcdma-ll.app.alcatel-lucent.com/livelink/livelink.exe?func=ll&objId=54454844&objAction=browse&sort=name&viewType=1

4WIPS

4.1WIPS RECOMMENDATIONS

In LA1.1 to change the parameter you could do directly in the system, edit the DLU file andchange the respective parameter, or you can extract the DLU file change the respectedparameter and upload again the DLU file in the system.

Open the XML database in the WIPS select the parameter you need to change, and after thechange to correctly update the parameter select SET to finalize the update.


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Figure 4.1-1: WIPS parameter changes

After select SETis necessary create a work order to be ease to see the changes in the template

and to be able to roll back into the previous configuration.Rename the work order and export the file into the live server repository.


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Figure 4.1-2: WIPS work order export

5LLDM MASK

5.1LOAD MASK

Each time we start UE connection in LLDM software is necessary to define the MASK withspecific parameters.

The only log data items you choose in Log Mask Setting Tree View are collected at LTE UE sideand sent to LLDM.

5.1.1Short Description

Some occasions when setup the UE configuration is necessary to setup correctly the LOG MASKthat will allow processing all the information collected during the tests with LLDM. In somespecific cases if we select too many parameter to check the UE cannot hang on such load andcrash. To avoid this problem follow next steps.

5.1.2Proposed Tests

Step 1 Select in the LOG MASK the parameters that is strictly necessary for your information.


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Step 2 Connect the UE and check the CH information load.

Step 3 The channel information load should be between 30% and 40% of the capacity. In somecases using 50% or higher we have UE crash.

Figure 5.1-1: Log Mask Setting Dialog


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Figure 5.1-2: CH1 MASK Load Information

6ACCESSIBILITY

6.1 SLEEPING CELL

6.1.1Short description

Sleeping Cells can be defined as Cells that do not provide support for LTE traffic for undefinedmeans i.e.

They have not been put into a locked state by the operator.

They do not report standard failure of service indications e.g. hardware or software alarms.

Due to their nature Sleeping Cells are difficult to detect and therefore cells in these conditionscan remain out of service for prolonged time periods causing major service outages.

Channel 1Load


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This feature provides an initial capability of detecting sleeping cells in the LA2.0 release. It usesalarm and performance information available from eNBs deployed in the field to detect sleepingcell conditions.

6.1.2Issue Description

t300, This UE timer is started when sending RRCConnectionRequest and is stopped uponreception of RRCConnectionSetup or RRCConnectionReject. Defined in TS 36.331. Broadcast insystemInformationBlockType2.

When the eNB transmits the RRC CONNECTION SETUP message to the UE a defense timer isstarted in order to prevent the scenario when the UE does not receive the message due to e.g.;cell reselection.

If the eNB does not receive RRC CONNECTION SETUP COMPLETE before the timer expiry, theRRC connection is considered as failed and the eNB will delete UE context and release anyassociated eNB resources.

Figure 6.1-1: RRC Connection scenario call flow

6.1.3Propose steps

Step 1 Using LLDM please selected in the log MASK (Radio Problem Cause).

Step 2 Check the signal level (RSSI, SNR and RSRP).

Step 3 Using the signal log message is possible to see where message the connection fails.


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Figure 6.1-2: T300 expire

6.1.4Workaround

If timer t300 expires:

1 - Reset MAC, release the MAC configuration and re-establish RLC for all RBs that areestablished;

2 - Inform upper layers about the failure to establish the RRC connection, upon which theprocedure ends.

3 Before the next two steps please take all the respected traces relevant for debugging

4 Lock/Unlock cell

5 Reboot cell


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6.2LAZY CELL


In the scenario of a Lazy Cell all looks OK from Network operation center - RRH is TX'ing, UE canread MIB/SIB, RACH does work, UE will see rrcConnectionSetup, butrrcConnectionSetupComplete is not received by eNB.

6.2.2Issue description

In the Radio Problem Cause menu the MAC_RA_PROBLEM message is reported. This is indicationof Random access problem from MAC while neither T300, T301, T304 nor T311 is running.

Figure 6.2-1: MAC RA Problem


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Figure 6.2-2: RRC connection establishment procedure

6.2.3Propose steps

Step 1 Using LLDM please selected in the log MASK (Radio Problem Cause).

Step 2 Check the signal level (RSSI, SNR and RSRP).

6.2.4Workaround

1 Before the next two steps please take all the respected traces relevant for debugging

2 Lock/Unlock cell

3 Reboot cell

eNB doesnt receivethe RRCConnectionSetupComplete fromUE side


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7.1.2.1 RRC Connection Reestablishment:

In a number of failure cases (e.g. radio link failure, handover failure, RLC unrecoverable error,reconfiguration compliance failure), the UE initiates the RRC connection reestablishmentprocedure, provided that security is active. If security is not active when one of the indicatedfailures occurs, the UE moves to RRC_IDLE instead.

To attempt RRC connection re-establishment, the UE starts a timer known as T311 and performs

cell selection. The UE should prioritize searching on LTE frequencies. However, no requirementsare specified as to for how long the UE shall refrain from searching for other RATs. Upon findinga suitable cell on an LTE frequency, the UE stops the timer T311, starts the timer T301 andinitiates a contention based random access procedure to enable theRRCConnectionReestablishmentRequest message to be sent. In theRRCConnectionReestablishmentRequest message, the UE includes the identity used in the cell inwhich the failure occurred, the identity of that cell, a short Message Authentication Code and acause.

7.1.2.2 Tracking Area Update:

If the UE has moved to a cell which belongs to a different tracking area, it will establish a briefsignaling connection with the eNB to inform it about its new location within the new trackingarea before it enters the paging reception stage.

Since we have RRC ConnectionReestablishmentReject and after a tracking area update requestduring some seconds we dont have any data transfer, as you can see in the figure bellow.


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Figure 7.1-2: No data throughput during HO phase

7.1.3Workaround

1 Check adjacency neighbor list

7.2TCPACKFREQUENCY MODIFICATION


Accordingly to last trial feedbacks; it was observed that in some case there was a U-plane

packet loss during or shortly during HO.


It was found that with those settings the HO gap can be reduced as the impact of packet lossduring HO can be recovered quicker. It depends whether you see U-plane packet loss during orshortly after HO.


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7.2.3Workaround

Step 1 TSHARK - UE Hardware Interface ID

Ensure Wireshark is installed, and then run TSHARK-CTC.bat to checkChoose the right device from the list

E.g./ Samsung UE interface id = ****9DD2

Figure 7.2-1: TSHARK - UE Hardware Interface ID

Step 2 TCPoptimizer Edit Registry

Run TCP Optimizer

Go to Preference | Check Enable Registry Editor

tshark-ctc.bat


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Step 4 TCPoptimizer Modify Value

Edit DWORD Value | Value Data = 1 (Decimal)

Exit TCPoptimizer| Restart Windows

Figure 7.2-4: TCPoptimizer Modify Value

7.2.4Important Notes /Comments:

In some cases, the same UE may be having different interface IDs.

After windows restart (or any new test campaign), run TSHARK-CTC to ensure UE is still havingthe same ID as before.

Otherwise, repeat the steps described in this slides.

NOTE:There may be other ways to identify the ID not described in this slides.

BEST PRACTICE:Backup the registry before any modification.

CAUTION:Setting TcpAckFrequency = 1 is just a workaround for FTP throughput Gap issueduring HO. This setting may not be optimum for other test cases, as it increases the overheadesp. on the uplink.


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8STATIC TRANSPORT FIBER DELAY LENGHT

8.1FIBER DELAY LENGTH CONFIGURATION


The length of the fiber that connects the CpriRadioEquipment to the d2u is specified by thestaticTransportFiberDelayLength parameter. This value is specified in meters.


Based in recent investigations in Vlizy, a specific delay is advised to be used for the fiberconnection. This value is calculated based in calculus that for a fiber of 900m the delay to beused is of 200ms. Then to calculate the value to be used one can linearly use the followingformula:

Correct delay parameter = (real fiber length d2U to RRH / 900m) * 200ms

8.1.3CTC Examples

For the indoor installation site (cell 50 in site 16 (EXPO Axis)), was two equal fibers lengths(530m) to connect indoor antennas, the calculated delay was 118ms.

Mainly the test bellow was to see impact of optimum configuration versus non configured delay

Below the test you can find Throughput comparison with different fiber parameterization.

Figure 8.1-1: Cell 50 in Site 16 (Expo Axis)


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8.1.3.1 Comments:

Impact is more significant in DL FTP, while in UL FTP the gai is less significant.

For the Indoor installation for cell 198 in site 66 (CTC Puxi Business Hall) was used two equalfibers lengths (2000m) to connect indoor antennas; the calculated delay was 444ms.

Mainly the test was to the compromise in performance when introducing different fibers lengthsdelays beside the optimized one.

Below one can find Throughput comparison with different fiber parameterization

Figure 8.1-2: Cell 198 in Site 66 (CTC Puxi Business Hall)

8.1.3.2 Comments:

In this test main goal was to access different fibre lengths' delays (0m, 1Km, 1.5Km and 2Km).Possible to see that for distances bellow 1km we had improvement, for distances higher than1km the throughput decrease. Further tests need to run to confirm the results

9MULTI UE

It was seen during the Multi UE tests that in some cases an Unfair UL throughput sharing wasoccurring. In order correct this behavior this hint was built.

9.1UNFAIR UL THROUGHPUT SHARING


When using 8 UE in parallel in different conditions such as in Near Cell, Medium Cell and CellEdge the throughput according to ulSchedPropFairAlphaFactorparameter could be allocateddifferent PRBs for each UE.

9.1.2Propose steps

Step 1 Performed a FTP UL test with only one


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Step 2 Check the throughput reach with one UE

Step 3 Performed a FTP UL test with 8UEs in different RF conditions

Step 4 Check the throughput reach with each UE


In the following table is possible to see the different throughput between different UEs.

The parameter ulSchedPropFairAlphaFactorwas configure to be equal = 1 (aggressivescheduler). With this the fairness is notreached.

Table 9-1: Unfair Throughput

9.1.4Workaround

The parameter ulSchedPropFairAlphaFactorcould be configured to be less aggressive and likethis we had a fair throughput sharing

Setting up ulSchedPropFairAlphaFactor = 0we are able to setup the UL throughput fairness inall the UEs

SNR uL1Ttp uL1Ntp uTTI% uRB% utRB% uMCS DLnack% Rank PLavg

UE1 10.59 0.76 0.73 65.89 12.14 8 11.36 5.57 2 92

UE2 0.8 0.8 0.76 70.05 11.52 8.07 11.24 15.8 1.97 101

UE3 10.21 0.81 0.77 65.47 12.51 8.19 11.66 5.6 2 92

UE4 19.71 0.81 0.78 49.41 16.6 8.2 11.23 5.86 2 78

UE5 9.2 0.8 0.77 62.62 13.14 8.23 11.55 5.6 2 85

UE6 1.83 0.8 0.77 50.86 16.54 8.41 10.93 5.83 1.63 93

UE7 10.38 0.81 0.77 61.78 13.07 8.08 11.57 6.22 2 84

UE8 19.47 0.8 0.77 60.62 13.38 8.11 11.58 5.92 2 71

Table 9-2: Fair Throughput

9.1.5MU parameter setting

9.1.5.1 UL Parameters

PUSCH SINR Target = 4 dB

FbFunction numberOfPoints = 2 (as per default Ed13 DLU)

Unfair

SN R u L 1T t p u L 1 N t p u T TI% u R B % u tR B % u M C S D L n a c k % R an k PL a v g

U E1 1 0.9 5 0 .5 3 0 .5 1 4 9 .51 1 1 .4 5 .65 10 .9 1 5 .5 3 2 9 1

U E2 1.1 3 0 .1 6 0 .1 6 1 4 .96 12 .2 1 1 .83 9 .0 3 2 .9 7 1 .9 8 10 1

U E3 10 .6 1 .0 3 0 .9 8 7 1 .48 14 .0 8 1 0 .06 11 .6 8 6 .4 7 2 9 2

U E4 1 9.8 9 1 .2 4 1 .1 9 8 0 .53 1 4 .9 12 11 .7 7 5 .7 2 2 7 8U E5 9.4 7 0 .9 3 0 .8 7 5 5 .8 15 .6 5 8 .73 11 .7 9 5 .6 4 2 8 4

U E6 1.4 9 1 .1 3 1 .0 6 7 6 .83 14 .4 1 1 1 .07 11 .6 6 5 .8 4 1 .5 1 9 4

U E7 1 0.8 1 1 .1 2 1 .0 6 7 9 .89 13 .3 9 1 0.7 11 .8 9 5 .7 4 2 8 4

U E8 1 9.8 7 0 .6 6 0 .6 2 5 7 .53 11 .3 8 6 .55 11 .4 6 6 .2 1 2 7 1

FairThroughput


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FmFunction and FnFunction numberOfPoints = 4 (as per default Ed13 DLU)

ulSchedPropFairAlphaFactor = 0 (PF scheduler)

maxNbrOfUsersForStretchingPHlimit = 8

ulBOperiodicIncreaseEnabled = disabled (for all four MAC bearers)

UL Initial BLER Target = 10%

9.1.5.2 DL Parameters

dlSinrThresholdBetweenCLMimoTwoLayersAndOneLayer=10.0

dlSinrThresholdBetweenOLMimoAndTxDiv=10.0

nomPdschRsEpreOffset= -2

DL Tx Mode = CL-MIMO (Full Mode)

DL Initial BLER Target = 10%

10NEIGHBOURS PLANNING AND CELL ID PLANNING

In commercial networks or trials that coexisting already many eNB Same approach can beapplied to adjacent cluster sites of an already optimized cluster;

First optimized adjacent sites must be included in the computation zone, but not in the focuszone which should contain only the sites to optimize.

10.1NEIGHBORS PLANNING


The main planning rule is to re-use cell ID with a sufficient distance in order to avoidinterferences.

This distance depends on propagation path loss, the environment and the frequency.

A correct RF design and optimization induces average number neighbors between 16 and 25 percell.

The main criteria are the following one:

Considering two cells cell A and cell B, on the same frequency carrier using the same cell ID,the distance between those must satisfy the following criteria:

RSRP

At cell A edge (RSRPcellA -115dBm) : RSRPcellA

At cell B edge (RSRPcellB -115dBm): RSRPcellB


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In term of distance the range of distance where the radio conditions detailed above areanalyzed.

Dense urban/ urban for all frequency bandsMaximum distance to analyze neighbors conditions: 8km

Suburban for all frequency bands

Maximum distance to analyze neighbors conditions: 30km

Rural for all frequency bands

Maximum distance to analyze neighbors conditions: 30km

10.2CELL ID PLANNING

Cell ID plan use the same radio criteria than the ones for neighboring plan, but the process isnot the same, some added constraints must be taken into account.


One can find some quick note regarding the lessons learned about cell planning for LTENetworks.

Theoretical definition should be:

PCI:(physicalLayerCellIdentityGroupIndex *3 ) + physicalLayerCellIdentityIndex

physicalLayerCellIdentityGroupIndex between 0 and 167 (included)

physicalLayerCellIdentityIndex between 0 and 2 (included)

So 3 sectors belonging to the same site have a common group index but different cell identityindex (0, 1 and 2).

Bear also in mind the cell ID planning. 2 cells with modulo 3 cell IDs interfere more against each

other in the DL.Since the RS signal occupies each 6th RE within a OFDMA symbol, the Cell Planning should bethat the cell and its immediate neighbors should have cell Ids 0, 1, 2, 3, 4 and 5 surrounded bycells 6, 7, 8, 9, 10, 11 etc...


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Figure 10.2-1: Cell ID Planning MOD 3 and MOD 6 matrix

10.2.1.1Comments:

Typical example case for a MOD 3 and 6 matrixes, that helps to identify the bad relationsbetween Cell IDs.

If Cell A is oriented to Cell B then we have to use the follow relation:A = B + n*3, n = 0, 1, 2, 3, ...

10.3RSRP CRITERIA


Cell id is required to identify each cell, a cell id is the combination of one of the 3 sequencessupported by P-SCH and the group Id supported by S-SCH.

So Realizing a cell id planning = realizing P-SCH planning and S-SCH planning

The strategy recommended is to use the same S-SCH per site which induces that each sectoruses a different P-SCH sequence

This distance depends on propagation path loss, the environment and the frequency.

The main criteria are the following ones:

Considering two cells cell A and cell B, on the same frequency carrier using the same


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cell ID, the distance between those must satisfy the following criterias:

RSRP criterion to respect on the field

At cell A edge (RSRPcellA -115dBm) : RSRPcellA

At cell B edge (RSRPcellB -115dBm): RSRPcellB

10.3.1.1Comments:

The above rules should be followed, to avoid the risk of getting extra interference.

10.4DISTANCE CRITERIA


Distance criteria, but it can not be used alone as it assume an homogeneous environment whichis not always the case

Dense urban/ urban

2km @ 2600MHz considering 600m cell radius

2,4km @ 1800MHz and 2100MHz considering 700m cell radius

5,5km @ 850MHz and 900MHz considering 1,7km cell radius

6Km @ 700MHz considering 1,9km cell radiusSuburban

6km @ 2600MHz considering 1,8km cell radius

7km @ 1800MHz and 2100MHz considering 2,2km cell radius

18km @ 850MHz and 900MHz considering 5,5km cell radius

20Km @ 700MHz considering 6km cell radius

Rural

17km @ 2600MHz considering 6km cell radius

21km @ 1800MHz and 2100MHz considering 7km cell radius

60km @ 850MHz and 900MHz considering 18km cell radius

65Km @ 700MHz considering 20km cell radius

10.4.1.1Comments:

The above rules should be followed, to avoid the risk of getting extra interference.


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11ANTENNA POSITIONING

In order to achieve the best performance in DL on filed is quite important to respect the

antenna separation and positioning on the roof top of the drive test car This was evaluated atShang Nang Area.

In the Figure 10.4-1: and Figure 10.4-2: , one can find some identification for the correctcabling used and distance separation /positioning of the antennas.

Figure 10.4-1: Sol3 Antenna Ports

Figure 10.4-2: Antenna Distance Separation /Positioning

From the Figure 10.4-3: , what could be seen was that the positioning was influencing theperformance reached in the static test. In the different boxes identified with (1, 2 and 3) wehave different position /orientation setups. Accordingly to that the performance was changing.


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Figure 10.4-3: DL Traffic Impact

11.1.1.1Comments:

Detailed configuration used and performance highlight.

Rx DT antenna horizontal & Tx\Rx DT antenna vertical (~60Mbps)

Rx DT antenna vertical & Tx\Rx DT antenna vertical (~35Mbps)

Rx DT antenna vertical & Tx\Rx DT antenna horizontal (~40Mbps)

12FAQS

12.1HOW TO AVOID CALL DROP?

During RF optimization phase and RF parameter phase of a cluster, should be taken into accountthe following actions to avoid call drop inside cluster:


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Figure 12.1-1: LTE Cluster

12.1.1Propose steps

Step 1 First check on site during optimization phase (Tilts, Azimuths, cables)

Step 2 Drive test to get the best serving cells in the entire cluster

Step 3 With Optimization report prepare all the adjacencies possible to not drop the callduring handover between sites.

Step 4 Check all parameters that could impact Inter-Handover and Intra-Handover.

Step 5 Run a battery of tests inside the cluster such has mobility tests, static tests, multi UEtests and stability tests to avoid call drops.

12.2THE SNR IS GOOD, BUT THE UE COULD NOT ATTACH.WHAT CAN BE DONE?

In this case we have several possibilities for the UE couldnt connect to the network.

The best approach is check the messages in LLDM, would be easy to detect in witch way wecould go in the investigation.


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12.2.1Propose steps

Step 1 Check in the EPC if the IMSI associate to your UE is not blocked.Step 2 Check in the PCRF if the IMSI from your UE is not block.

Step 3 Check if the cell is not locked

Step 4 In the previous chapters another possibilities could be (Lazy Cell and Sleepy Cell)

Step 5 Check the value for parameter qRxLevMin.

In here you could contact system engineering to take the correct traces when you try to connectto investigate afterwards.

12.3THE SNR IS BAD EVEN UNDER THE SITE, AND THE UECOULD NOT ATTACH. WHAT CAN BE DONE?

In this case we have several possibilities for the bad SNR and the UE couldnt connect to thenetwork.

The best approach is check the messages in LLDM, would be easy to detect in witch way wecould go in the investigation.

12.3.1Propose steps

STEP 1 -Sites overshooting; it is pretty normal to have sites overshooting in a brand newnetwork. Usually the first step when detected is to introduce additional tilton the interferercell (considering that a specific cell should be dominant in a defined area). This step should berepeated while possible to introduce tilt without killing also the cell.

STEP 2 -Other approach if we observe that the main lob of the interferer cell is shooting in anundesired direction (azimuth); normally we can try to adjust the azimuthfor this interferercell.

STEP 3 -Last step when all the other two steps are not possible to perform, due to logisticsreason or any other reason; we can go for power reductionapproaches on the interferer cell.

NOTE:Take in to account that all these steps are interactive, and one should not expect toperform it once and thats it. Usually it is necessary to perform several runs.

12.4NAMING OF THE PATCH FILE FOR PQ3


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The issue was to avoid renaming old pq3 files into .old as the software will use these instead ofthe new ones.

12.4.1Propose steps to install a designer UPA, FPGA, or DSPimage on the CEM

STEP 1 - ftp or sftpto the PQ2 (on the CEM board), go to the /active/pq3directory andtransfer the private image(s) to that directory. Make sure you name the file the same as theoriginal in that directory.

NOTE:For LA2.0, you have to use the enb0xferlogin and password. Also, if you wantto keep the original files by renaming them, do not simply append .org or .old to the name ofthe file. Doing this will result in the eNB getting disabled, the BB getting disabled and aSoftware_anomaly_CE_global_setupalarm will getreported on the BB. We recommend that you rename the files, for example, to ori_ecectl.vxand ori_ucu3x.dspa instead.

STEP 2 - The private loads can be downloaded from the following server (password is blank):

ftp://[email protected]/UPA_Designer_Loads.

For Murray Hill users, many of the designer loads can be found on the white website.

STEP 3 - It may be necessary to make the active filesystem writeable; to do so type: mount -oremount rw /active

STEP 4 - Modify the cectlpackage.txtfile. If you are familiar with modifying the CDMA GDFfiles, then you will see that it follows the same structure. The first column is the board name,the second one is the file name, third is the directory path, next is the filesize and the lastcolumn is the checksum. Make sure you change the correct line.It is a little confusing because there are 4 FGPA images: combiner, a, b and c. There is also theDSP image. You have to update the file size, and for the checksum you have to either put thecorrect checksum or all zeroes.

STEP 5 -Save your changes, and reboot the entire eNB

Example with private UPA, and DSP load:

77df 74e0 cect l package. t xt

BNJ 103 cect l . vx . / 5821265 0x00000000 0x00000001


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dlSinrThresholdBetweenCLMimoTwoLayersAndOneLayer= 15.0

dlSpeedThresholdBetweenCLMimoTwoLayersAndOneLayer= 0

dlSpeedThresholdForDisablingPMI=0

For Enb/1 CellConf/0 CellMIMOConf/0 CodebookSubsetRestriction/0attribute

n2TxAntennaTm4OneLayerCodebook0= true




n2TxAntennaTm4TwoLayersCodebook1= true


12.7.2MIMO CLOSE LOOP Mixed mode

For Enb/1 cellConf/0 Cell2DLConf/0 attribute

transmissionMode = tm4

cqiReportingModeAperiodic = rm31

For Enb/1 CellConf/0 CellMIMOConf/0 attributedlFullCLMimoMode= false

dlMIMODefaultCodeBook = 2LayersCodebook1

dlMimoSinrSwitchAveragingCoefficient=252

dlSinrThresholdBetweenCLMimoAndTxDiv= 15.0

dlSpeedThresholdBetweenCLMimoAndTxDiv= 0

dlSpeedThresholdForDisablingPMI=0


n2TxAntennaTm4OneLayerCodebook0= false







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12.7.3MIMO OPEN LOOP


transmissionMode = tm3cqiReportingModeAperiodic = rm30

For Enb/1 CellConf/0 CellMIMOConf/0 attribute

dlFullCLMimoMode= false

dlMIMODefaultCodeBook = 2LayersCodebook1

dlMimoSinrSwitchAveragingCoefficient=252

dlSinrThresholdBetweenOLMimoAndTxDiv= 18.0

dlSpeedThresholdBetweenCLMimoAndTxDiv= 0






n2TxAntennaTm4TwoLayersCodebook1= false

n2TxAntennaTm4TwoLayersCodebook2= false

12.7.4TXDIV


transmissionMode = tm2cqiReportingModeAperiodic = rm30

12.7.5All modes comparison


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Table 12-1: All modes parameters change

13CONCLUSION

14ABBREVIATIONS AND DEFINITIONS

14.1ABBREVIATIONS

Acronym Description

AMR Adaptive Multi-Rate

BLER Block Error Rate

CCCH Common Control Channel

CH Channel

DL Downlink

DL-SCH Downlink Shared Channel

D2U Base Band Unit (BBU) d2U and d1U; A signal Distributed 2U (d-2U) digital unit, thisindoor unit contains the channel element cards and the control module.

eNB Evolved NodeB (or eNodeB) (combines functions of UMTS NodeB and RNC)

EPC Evolved Packet Core

FTP File Transfer Protocol

HO Handover

LLDM LGE UE Diagnostic Monitor

LTE Long Term Evolution

MIMO Multiple Input Multiple Output antenna technique

OFDMA Orthogonal Frequency Division Multiple Access DL air interface


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PCRF Policy Charging Rule Function

PRB Physical Resource Blocks

P-SCH Primary synchronization channel

PUSCH Physical Uplink Shared Channel

RAT Radio Access Technology

RF Radio Frequency

RLC Radio Link Control

RRC Radio Resource Control (3GPP TS 36.331)

RRH Remote Radio Head

RS Reference Symbol

RSRP Reference Signal Received Power

RSSI Received Signal Strength Indicator

SNR Signal to Noise Ratio

SINR Signal to Interference-plus-Noise Ratio

S-SCH Secondary Synchronization Channel

UDP User Datagram Protocol

UE User Equipment (similar to Access Terminal in EV-DO)

UL Uplink (equivalent to EV-DO Reverse Channel) LTE supports peak data rate of 80 MbpsUL

WIPS Wireless Provisioning System

14.2DEFINITIONS

END OF DOCUMENT

Documents

RF TroubleShooting Guideline LA1.1