Rank Indication is one of the important input to eNB , in selection of the transmission layer in downlink data transmission. Even though the system is configured in transmission mode 3 (or open loop spatial multiplexing) for a particular UE and if the same UE report the Rank Indication value 1 to eNB, eNB will start sending the data in Tx diversity mode to UE . If UE report Rank Indication 2 , eNB will start sending the downlink data in MIMO mode (Transmission Mode 3).

Why we need this RI in LTE concept? When UE experience bad SNR and it would be difficult (error prone) to decode transmitted downlink data  it gives early warning to eNB by stating Rank Indication value as 1. When UE experience good SNR it pass this information to eNB by indicating rank value as 2.

Because of this reason, you might have observed that some time data transmitted by eNB is in Tx diversity mode, though MIMO was configured and hence you may have observed less downlink throughput than expected one. 

However, it is not necessary that eNB will always change the transmission mode based on RI value, it could be implementation specific decision.

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LTE L12 Radio Network Functionality

LTE MAC UL Tx Statistics

Time : 20:39:41.073

Length : 36

Log Code (Hex) : 0xB067

HW Timestamp : (2230372.50 ms) 00:37:10.373

1.25 ms fraction : 0.00

CFN : 56

1.25 ms counter : 1784298

ML1 Serving Cell Measurement Response

Time : 20:50:40.153

Length : 96

Log Code (Hex) : 0xB193

HW Timestamp : (2889445.00 ms) 00:48:09.445

1.25 ms fraction : 0.00

CFN : 44

1.25 ms counter : 2311556

Version : 1

Number of Subpackets : 1

Subpackets :

[0 ] :

Subpacket ID : 0x19

Subpacket Version : 3

Subpacket Size (bytes) : 80

Serving Cell Measurement Results

EARFCN : 2600

Physical Cell Id : 237

Current SFN : 287

Cell Timing [0] : 241700

Cell Timing [1] : 241700

Cell Timing SFN [0] : 287

Cell Timing SFN [1] : 287

Inst RSRP Rx[0] : -77.50 dBm

Inst RSRP Rx[1] : -90.25 dBm

Inst Measured Rsrp : -77.50 dBm

Inst RSRQ Rx[0] : -9.13 dB

Inst RSRQ Rx[1] : -8.00 dB

Inst RSRQ : -8.00 dB

Inst RSSI Rx[0] : -51.38 dBm

Inst RSSI Rx[1] : -65.25 dBm

Inst RSSI : -51.38 dBm

Residual Frequency Error : 0

SINR Rx[0] : 8.20 dB

SINR Rx[1] : 10.80 dB

LL1 PCFICH Decoding Results

Time : 20:39:41.073

Length : 180

Log Code (Hex) : 0xB12A

HW Timestamp : (2230373.75 ms) 00:37:10.374

1.25 ms fraction : 0.00

CFN : 180

1.25 ms counter : 1784299

Version : 1

Serving Cell Id : 237

Number of Records : 20

Subframe Number : 1

Reserved : 0

System Frame Number : 937

Cfi Value : 0

Subframe Records :

[0 ] :

SubframeOffset : 0

[1 ] :

SubframeOffset : 1

[2 ] :

SubframeOffset : 2

[3 ] :

SubframeOffset : 3

[4 ] :

SubframeOffset : 4

[5 ] :

SubframeOffset : 5

[6 ] :

SubframeOffset : 6

[7 ] :

SubframeOffset : 7

[8 ] :

SubframeOffset : 8

[9 ] :

SubframeOffset : 9

[10] :

SubframeOffset : 10

[11] :

SubframeOffset : 11

[12] :

SubframeOffset : 12

[13] :

SubframeOffset : 13

[14] :

SubframeOffset : 14

[15] :

SubframeOffset : 15

[16] :

SubframeOffset : 16

[17] :

SubframeOffset : 17

[18] :

SubframeOffset : 18

[19] :

SubframeOffset : 19

ML1 Grant Manager Dedicated Configuration

Time : 20:58:27.691

Length : 72

Log Code (Hex) : 0xB165

HW Timestamp : (3356827.50 ms) 00:55:56.828

1.25 ms fraction : 0.00

CFN : 144

1.25 ms counter : 2685462

Version : 4

_3gppStandardsVersion : 0

SR Configuration : Present

OptionalSrEnable : Disabled

SrPucchResourceIndex : 0

SrConfigurationIndex : 0

SrMaximumTransmissions : 0

CQI Configuration : Present

OptionalCqiEnable : Disabled

OptionalCqiReportingAperiodicPresent : Not present

NominalPdschRsEpreOffset : 8

OptionalCqiReportingPeriodicPresent : Not present

OptionalCqiReportingPeriodicEnable : Disabled

OptionalCqiFormatIndicator : Wideband CQI

OptionalSimultaneousAckNackAndCqi : Not Allowed

CqiPucchResourceIndex : 0

RiConfigIndex : 0

OptionalRiConfigEnabled : Disabled

K : 0

CqiPmiConfigIndex : 0

SRS Configuration : Present

OptionalSrsEnable : Disabled

SrsBandwidth : 0

SrsHoppingBandwidth : 0

FrequencyDomainPosition : 0

OptionalDuration : Single

TxCombination : 0

CyclicShift : 0

SrsConfigIndex : 0

PHR Configuration : Present

OptionalPhrEnable : Disabled

PeriodicPhrTimerValue : 0

ProhibitPhrTimerValue : 0

DlPathlossChangeThreshold : 0

PUSCH TPC Configuration : Present

OptionalPuschTpcEnable : Disabled

OptionalPuschTpcDciFormat : Format 3

PuschTpcIndex : 0

PuschTpcRnti : 0

PUCCH TPC Configuration : Present

OptionalPucchTpcEnable : Disabled

OptionalPucchTpcDciFormat : Format 3

PucchTpcIndex : 0

PucchTpcRnti : 0

ULSCH Configuration : Present

MaxHarqTransmissions : 5

OptionalTtiBundlingEnabled : Disabled

UL Power Control Configuration : Present

OptionalAccumulationEnabled : Enabled

P0UePusch : 0

P0UePucch_HighPart : -1

P0UePucch_LowPart : 0

OptionalDeltaMcsEnabled : Disabled

P_SrsOffset : 7

PUSCH Configuration : Present

DeltaOffsetAckIndex : 10

DeltaOffsetCqiIndex : 15

DeltaOffsetRiIndex : 12

PUCCH Configuration : Present

OptionalPucchCfgEnable : Disabled

AckNakFeedbackMode : 0

OptionalAckNakRepetitionEnabled : Disabled

AckNakRepetitionFactor : 0

n1PucchAnRep : 0

Antenna Configuration : Present

TransmissionMode : 2

OptionalTxAntennaSelection : Disabled

AntennaCodebookSubsetRestriction_LowPart : 0

AntennaCodebookSubsetRestriction_HighPart : 0

CDRX Configuration : Present

OptionalCdrxCfgEnable : Disabled

CdrxOnDurationTimer : 0

CdrxInactivityTimer : 0

CdrxDlDrxRetxTimer : 0

CdrxLongCycleLength : 0

CdrxCycleStartOffset : 0

OptionalCdrxShortDrxCycleEnable : Disabled

CdrxShortDrxCycleLength : 0

CdrxShortDrxTimer : 0

Service Request

Time : 21:05:27.397

Vendor Header

Length : 18

Log Code (Hex) : 0xB0EB

HW Timestamp : (3776733.75 ms) 01:02:56.734

1.25 ms fraction : 0.00

CFN : 172

1.25 ms counter : 3021387

KSI And Sequence Number

KSI : 1

Sequence number : 5

Message dump (Hex):

C7 25

RRC Connection Request (UL-CCCH)

Time : 21:05:27.397

Vendor Header

Length : 31

Log Code (Hex) : 0xB0C0

HW Timestamp : (3776735.00 ms) 01:02:56.735

1.25 ms fraction : 0.00

CFN : 16

1.25 ms counter : 3021388

RRC Signaling Header

Log Packet Version : 2

RRC Release Number : 9.3.0

Radio Bearer Id : 0

Physical Cell Id : 237

E-ARFCN : 2600

System Frame Number

System frame number : N/A

Sub frame number : N/A

Message Type : CcchUplink

Message Length : 6

criticalExtensions : rrcConnectionRequest-r8

rrcConnectionRequest-r8

ue-Identity

InitialUE-Identity : s-TMSI

s-TMSI

mmec

mmec : (0x2) : 2

m-TMSI : (0xC8E0F268) : 3370185320

establishmentCause : mt-Access

spare : 0

[0 ] : 0

Message dump (Hex):

40 2C 8E 0F 26 84

LL1 PUCCH CSF Log

Time : 20:50:40.153

Length : 20

Log Code (Hex) : 0xB14D

HW Timestamp : (2889452.50 ms) 00:48:09.453

1.25 ms fraction : 0.00

CFN : 184

1.25 ms counter : 2311562

Version : 2

Start system Subframe Number (SFN) : 2

Start system frame number : 288

CSF Tx Mode : Open-loop spatial multiplexing

PUCCH Reporting Mode : MODE_1_0

PUCCH Report Type : Type 3, RI feedback

Number of subbands : 9

Rank Index : 0

Paging (PCCH)

Time : 20:39:41.218

Vendor Header

Length : 34

Log Code (Hex) : 0xB0C0

HW Timestamp : (2230453.75 ms) 00:37:10.454

1.25 ms fraction : 0.00

CFN : 140

1.25 ms counter : 1784363

RRC Signaling Header

Log Packet Version : 2

RRC Release Number : 9.3.0

Radio Bearer Id : 0

Physical Cell Id : 237

E-ARFCN : 2600

System Frame Number

System frame number : N/A

Sub frame number : N/A

Message Type : Pcch

Message Length : 9

pagingRecordList

PagingRecordList :

[0 ] :

ue-Identity

PagingUE-Identity : s-TMSI

s-TMSI

mmec

mmec : (0x2) : 2

m-TMSI : (0xC2B050EC) : 3266334956

cn-Domain : ps

Message dump (Hex):

40 00 2C 2B 05 0E C0 00 00

ESM Information Response

Time : 11:41:41.491
Vendor Header
Length : 37
Log Code (Hex) : 0xB0E3
HW Timestamp : (70928885.00 ms) 19:42:08.885
1.25 ms fraction : 0.00
CFN : 120
1.25 ms counter : 805512103108
Protocol discriminator : (2) EPS session management messages
EPS Bearer Identity : 0
Procedure Transaction Identity : 12
Message type : 218
Access point name
Access point name value : broadband

ESM Information Request

Time : 11:41:41.491
Vendor Header
Length : 19
Log Code (Hex) : 0xB0E2
HW Timestamp : (70928885.00 ms) 19:42:08.885
1.25 ms fraction : 0.00
CFN : 76
1.25 ms counter : 805512103108
Protocol discriminator : (2) EPS session management messages
EPS Bearer Identity : 0
Procedure Transaction Identity : 12
Message type : 217

Identity Response

Time : 11:41:41.086
Vendor Header
Length : 33
Log Code (Hex) : 0xB0ED
HW Timestamp : (70928535.00 ms) 19:42:08.535
1.25 ms fraction : 0.00
CFN : 24
1.25 ms counter : 805512102828
Protocol discriminator : (7) EPS mobility management messages
Security Header Type : 0
Message type : 86
Mobile identity
Odd/even indication : (1) Odd number of digits
Type of identity : (1) IMSI
Identity digits (BCD) : 310980300013567

Identity Request

Time : 11:41:41.086
Vendor Header
Length : 19
Log Code (Hex) : 0xB0EC
HW Timestamp : (70928533.75 ms) 19:42:08.534
1.25 ms fraction : 0.00
CFN : 188
1.25 ms counter : 805512102827
Protocol discriminator : (7) EPS mobility management messages
Security Header Type : 0
Message type : 85
Identity type 2
Type of identity : (1) IMSI

Attach Accept

Time : 11:41:42.131
Vendor Header
Length : 152
Log Code (Hex) : 0xB0EC
HW Timestamp : (70929508.75 ms) 19:42:09.509
1.25 ms fraction : 0.00
CFN : 64
1.25 ms counter : 805512103607
Protocol discriminator : (7) EPS mobility management messages
Security Header Type : 0
Message type : 66
EPS Attach Result
spare : 0
EPS Attach Result Value : (2) Combined EPS/IMSI attach
GPRS timer
Unit : (1) Value is incremented in multiples of 1 minute
Value : (30) 30 minutes
Tracking area identity list
Length : 6
spare : 0
Type Of List : (0) list of TACs belonging to one PLMN, with non-consecutive TAC values
Number Of Elements : 1 Elements
TrackingAreaIdentity
plmn
Mobile country code (MCC) : 310
Mobile network code (MNC) : 980
TAC : 64257
TACValues :
NASMessageContainer
Protocol discriminator : 2 (ESM)
MessageType : Activate Default EPS Bearer Context Request
Message Contents : 52 0C C1 01 08 1D 09 62 72 6F 61 64 62 61 6E 64 06 6D 6E 63 39 38 30 06 6D 63 63 33 31 30 04 67 70 72 73 05 01 0A 5D 0A 1F 5D 01 00 30 10 14 92 1F 73 96 FE FE 73 2A FF FF 00 81 00 54 00 32 05 82 34 01 08 5E 04 FE FE 81 54 27 15 80 80 21 0A 02 00 00 0A 83 06 AC 1A 26 02 00 0D 04 AC 1A 26 01
GUTI
Length : 11
Odd/even indication : (0) Even number of digits
Type of identity : (6) Reserved
plmn
Mobile country code (MCC) : 310
Mobile network code (MNC) : 980
MMEGroupID : 65520
MMECode : 1
M_TMSI : 3490051258
Location Area Identification
Mobile country code (MCC) : 310
Mobile network code (MNC) : 980
Location area code (LAC) : 49000 (Hex 0xBF68)
Mobile identity
Odd/even indication : (0) Even number of digits
Type of identity : (4) TMSI/P-TMSI
TMSI/P-TMSI : Hex 0x0110F0EA

Attach Request

Time : 11:41:41.070
Vendor Header
Length : 119
Log Code (Hex) : 0xB0ED
HW Timestamp : (70928378.75 ms) 19:42:08.379
1.25 ms fraction : 0.00
CFN : 80
1.25 ms counter : 805512102703
Protocol discriminator : (7) EPS mobility management messages
Security Header Type : 0
Message type : 65
NAS Key Set Identifier
TSC : (0) native security context
Key : 0
EPS Attach Type
EPS Attach Type Value : (2) combined EPS/IMSI attach
Old GUTI or IMSI
Length : 11
Odd/even indication : (0) Even number of digits
Type of identity : (6) Reserved
plmn
Mobile country code (MCC) : 310
Mobile network code (MNC) : 980
MMEGroupID : 9500
MMECode : 2
M_TMSI : 3758224433
UE Network Capability
Length : 4
128EEA0 : (1) supported
128EEA1 : (1) supported
128EEA2 : (1) supported
EEA3 : (0) not supported
EEA4 : (0) not supported
EEA5 : (0) not supported
EEA6 : (0) not supported
EEA7 : (0) not supported
128EIA1 : (1) supported
128EIA2 : (1) supported
EIA3 : (0) not supported
EIA4 : (0) not supported
EIA5 : (0) not supported
EIA6 : (0) not supported
EIA7 : (0) not supported
UEA0 : (1) supported
UEA1 : (1) supported
UEA2 : (0) not supported
UEA3 : (0) not supported
UEA4 : (0) not supported
UEA5 : (0) not supported
UEA6 : (0) not supported
UEA7 : 0
UCS2 : The UE has a preference for the default alphabet (defined in 3GPP TS 23.038 [3]) over UCS2 (see ISO/IEC 10646 [29]).
UIA1 : (1) supported
UIA2 : (0) not supported
UIA3 : (0) not supported
UIA4 : (0) not supported
UIA5 : (0) not supported
UIA6 : (0) not supported
UIA7 : (0) not supported
SpareArray :
NASMessageContainer
Protocol discriminator : 2 (ESM)
MessageType : PDN Connectivity Request
Message Contents : 02 0C D0 11 D1 27 1A 80 80 21 10 01 00 00 10 81 06 00 00 00 00 83 06 00 00 00 00 00 0D 00 00 0A 00
Old P-TMSI signature
Value : 59200 (Hex 0x00E740)
Additional GUTI
Length : 11
Odd/even indication : (0) Even number of digits
Type of identity : (6) Reserved
plmn
Mobile country code (MCC) : 310
Mobile network code (MNC) : 980
MMEGroupID : 65520
MMECode : 5
M_TMSI : 4026791086
Last visited registered TAI
plmn
Mobile country code (MCC) : 310
Mobile network code (MNC) : 980
TAC : 64257
DRX parameter
Split PG cycle code : (10) Value: 10
CN Specific DRX cycle length coefficient : (0) CN Specific DRX cycle length coefficient not specified
Split on CCCH : (0) Split pg cycle on CCCH is not supported by the MS.
Non-DRX timer : (2) Max 2 sec non-DRX mode after transfer state.
MS Network Capability
GEA/1 : (1) Encryption algorithm GEA/1 available
SM capabilities via dedicated channels : (1) MS supports mobile terminated point to point SMS via dedicated signalling channels.
SM capabilities via GPRS channels : (1) MS supports mobile terminated point to point SMS via GPRS packet data channels.
UCS2 support : (0) The ME has a preference for the default alphabet (defined in GSM 03.38) over UCS2.
SS Screening Indicator : 1, Defined in 24.080
SoLSA Capability : (0) The ME does not support SoLSA.
Revision level indicator : (1) The ME is Release '99 onwards
PFC feature mode : (1) Mobile station does support BSS packet flow procedures
Extended GEA bits
GEA/2 : (1) Encryption algorithm GEA/2 available
GEA/3 : (1) Encryption algorithm GEA/3 available
GEA/4 : (0) Encryption algorithm GEA/4 not available
GEA/5 : (0) Encryption algorithm GEA/5 not available
GEA/6 : (0) Encryption algorithm GEA/6 not available
GEA/7 : (0) Encryption algorithm GEA/7 not available
LCS VA capability : (0) Location request notification via PS domain not supported
PS inter-RAT HO to UTRAN Iu mode capability : (0) PS inter-RAT HO to UTRAN Iu mode not supported
Old LAI
Mobile country code (MCC) : 310
Mobile network code (MNC) : 980
Location area code (LAC) : 9500 (Hex 0x251C)
Mobile Station Classmark 2
Revision level : (2) Mobile station supporting R99 or later versions of the protocol
ES IND : (1) "Controlled Early Classmark Sending" option is implemented in the MS
A5/1 : (0) Encryption algorithm A5/1 available
RF Power Capability : (3) class 4
PS capability (pseudo-synchronization capability) : (1) PS capability present
SS Screening Indicator (defined in TS 24.080) : 1
SM capability (MT SMS pt to pt capability) : (1) Mobile station supports mobile terminated point to point SMS
VBS notification reception : (0) No VBS capability or no notifications wanted
VGCS notification reception : (0) No VGCS capability or no notifications wanted
FC Frequency Capability : (1) (GSM900 only:) The MS supports E-GSM or R-GSM
CM3 : (1) The MS supports options that are indicated in classmark 3 IE
LCS VA capability : (1) LCS value added location request notification capability supported
UCS2 : (0) The ME has a preference for the default alphabet (defined in GSM 03.38) over UCS2.
SoLSA : (0) The ME does not support SoLSA.
CMSP: CM Service Prompt : (1) "Network initiated MO CM connection request" supported for at least one CM protocol.
A5/3 : (1) Encryption algorithm A5/3 available
A5/2 : (0) Encryption algorithm A5/2 not available

RRC Connection Release (DL-DCCH)

Time : 11:41:40.821
Vendor Header
Length : 27
Log Code (Hex) : 0xB0C0
HW Timestamp : (70928246.25 ms) 19:42:08.246
1.25 ms fraction : 0.00
CFN : 68
1.25 ms counter : 805512102597
RRC Signaling Header
Log Packet Version : 2
RRC Release Number : 9.3.0
Radio Bearer Id : 1
Physical Cell Id : 270
E-ARFCN : 5780
System Frame Number
System frame number : N/A
Sub frame number : N/A
Message Type : DcchDownlink
Message Length : 2
rrc-TransactionIdentifier : 0
criticalExtensions : c1
c1 : rrcConnectionRelease-r8
rrcConnectionRelease-r8
releaseCause : other

Tracking Area Update Reject

Time : 11:41:40.290
Vendor Header
Length : 19
Log Code (Hex) : 0xB0EC
HW Timestamp : (70927743.75 ms) 19:42:07.744
1.25 ms fraction : 0.00
CFN : 96
1.25 ms counter : 805512102195
Protocol discriminator : (7) EPS mobility management messages
Security Header Type : 0
Message type : 75
EMM Cause
Value : (10) Implicitly detached