Module 3 DT-Drive Test Parameters

5/27/2018 Module 3 DT-Drive Test Parameters

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Understanding Drive Data

EcNo, RSCP, UE Tx Power and RSSI


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Commercial in Confidence 2007-04-112

Introduction

The is presentation contains simplified guides for determining RF

failure reasons and air-interface quality from drive data. Intention of these guides is:

Assist in initiating pro-active optimization plans.

Determine if failure reason(s) is due to air-interface, sector, site,

transport or network issues?

General data preparation and visual analysis work flow is alsopresented.

It is recommended the Engineer understand UMTS call procedures,

network timers/thresholds and interface protocols to attain overall

network optimization skills.


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Definitions3GPP TS 25.215

CPICH Ec/No:Received energy per chip divided by the power density in the band. The CPICH

Ec/No is identical to CPICH RSCP/UTRA Carrier RSSI. Measurement shall beperformed on the Primary CPICH.

UTRA CARRIER RSCP:Received Signal Code Power, the received power on one code measured on the

Primary CPICH.

Carrier RSSI:

Received Signal Strength Indicator. The received wide band power, includingthermal noise and noise generated in the receiver, within the bandwidth defined by

the receiver pulse shaping filter.

UeTxPwr:Total UE transmitted power on one carrier

Where: n = PSC

(mW)

)(mW

_

___/ RSSICarrier

RSCPCPICH

NoEc

n

n

(dB)(dBm)(dBm) ___ nn EcNoRSCPRSSICarrier


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RSSI, RSCP and EcNo Relationship

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

UARFCN

PercentageContribution

ToCarrierRSSI

Other & Noise

RSCP_psc8

RSCP_psc7

RSCP_psc6

RSCP_psc5

RSCP_psc4

RSCP_psc3

RSCP_psc2

RSCP_psc1

RSSI

RSCP

3.84Mhz


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RSSI, RSCP and EcNo Relationship

mW dBm EcNo mW dBm

RSCP_psc1 5.01E-13 -93 -8.0 RSSI 3.16E-12 -85

RSCP_psc2 6.31E-14 -102 -17.0

RSCP_psc3 1.26E-13 -99 -14.0

RSCP_psc4 3.16E-13 -95 -10.0

RSCP_psc5 2.00E-13 -97 -12.0

RSCP_psc6 6.31E-14 -102 -17.0

RSCP_psc7 7.94E-14 -101 -16.0

RSCP_psc8 5.01E-14 -103 -18.0

Other & Noise 1.76E-12 -87.5 -2.5

mW dBm EcNo mW dBm

RSCP_psc1 3.98E-13 -94 -4.1 RSSI 1 .02E -12 -89. 9

RSCP_psc2

RSCP_psc3RSCP_psc4

RSCP_psc5

RSCP_psc6

RSCP_psc7

RSCP_psc8

Other & Noise 6.25E-13 -92.0 -2.1

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

mW

PercentageContributionToCarrierRSSI

Other & Noise

RSCP_psc8

RSCP_psc7

RSCP_psc6

RSCP_psc5

RSCP_psc4

RSCP_psc3

RSCP_psc2

RSCP_psc1

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

mW

PercentageCo

ntributionToCarrierRSSI

Other & Noise

RSCP_psc8

RSCP_psc7

RSCP_psc6

RSCP_psc5

RSCP_psc4

RSCP_psc3

RSCP_psc2

RSCP_psc1


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Drive Data Preparation and Analysis

Following is a simple process:

Merge drive data files (as required)

Create plots of: Call events

Serving/best cell/PSC

EcNo/RSCP of serving/best PSC

RSSI plot

UeTx Power

Active set size, actual or simulated (optional) Number of PSCs within 5dB of serving/best PSC (optional)

Review call events Identify dropped calls, failed ASUs, etc

Areas with high number of ASUs

Identify areas with large number (>3) PSCs within 5dB

Use matrices in following slides to assist analysis


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Simplified RF Quality Matrix

EcNo, RSCP and RSSI

EcNo / RSCP

HIGH LOW

R

SSI

HIGH

LOW

Good Coverage

Good Quality

Low Pollution

Good Coverage

Poor Quality

Interference / Pollution

Poor Coverage

Good Quality

Low Pollution

Poor Coverage

Poor Quality

Possible Pollution



Simplified RF Failure Symptom Matrix

EcNo, RSSI and UE TxPwr

EcNo

HIGH LOW

UE Tx Pwr

LOW HIGH LOW HIGH

RSSI

HIGH

LOW

No RF Issue.

Check Hardware,

Transport, Protocol,

Timer Expiration,

etc issues.

Limited UL.

Check UL Receive

Hardware Or UL

Interference.

DL Interference.

Check Missing

Neighbours Or

External

Interference.

UL/DL Interference.

Check Cell Overlap,

Serving Cell

Distance, Ant. Tilts

etc

DL Coverage. UL Coverage.

DL Coverage Hole.

Check Cell Overlap,

Serving Cell

Distance, Ant. Tilts

etc

Lack of Coverage

(DL & UL).



0

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-18

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-2

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-6

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-10

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-14

-16

-18

0

-2

-4

-6

-8

-10

-12

-14

-16-18

0

-2

-4

-6

-8

-10

-12

-14

-16

-18

0

-2

-4

-6

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-10

-12

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-16

-18

0

-2

-4

-6

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-10

-12

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0

-2

-4

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13:18:07

13:18:17

13:18:27

13:18:37

13:18:47

13:18:57

13:19:30

13:19:40

13:19:50

13:20:00

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13:20:40

13:20:50

13:21:00

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13:21:50

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13:22:50

13:23:00

13:23:10

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13:23:40

13:23:50

13:24:00

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13:24:50

13:25:00

13:25:10

Time

EcNo(d

B)

-100.0

-90.0

-80.0

-70.0

-60.0

-50.0

-40.0

-30.0

-20.0

-10.0

0.0

10.0

20.0

13:18:07

13:18:18

13:18:29

13:18:40

13:18:51

13:19:25

13:19:36

13:19:47

13:19:58

13:20:09

13:20:20

13:20:31

13:20:42

13:20:53

13:21:04

13:21:15

13:21:26

13:21:37

13:21:48

13:21:59

13:22:10

13:22:21

13:22:32

13:22:43

13:22:54

13:23:05

13:23:16

13:23:27

13:23:38

13:23:49

13:24:00

13:24:11

13:24:22

13:24:33

13:24:44

13:24:55

13:25:06

13:25:17

Time

RSSI(dB)/UETxPwr(dBm)

0.0

1.0

2.0

3.0

4.0

ActiveSetSize

UeTxPwr RSSI ActiveSetSize

Example 1: Dedicated-modeDownlink

PSC_7

PSC_1

PSC_3

PSC_2

PSC_4

PSC_5

PSC_6

PSC_81

2

3

4

1

2 3

4

Dropped call

3

4

2

1

Serving Cell/PSC Plot



-20.0

-18.0

-16.0

-14.0

-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

0.0

9:52:16

9:52:25

9:52:34

9:52:42

9:52:51

9:53:00

9:53:08

9:53:17

9:53:25

9:53:34

9:53:43

9:53:51

9:54:00

Ec

No(dB)

-95.0

-90.0

-85.0

-80.0

-75.0

-70.0

-65.0

-60.0

RSSI(dBm)

PSC1_EcNo PSC2_EcNo PSC3_EcNo PSC3_EcNo PSC4_EcNo RSSI

Example 2: Idle-mode

Impact of #servers and

individual contribution

Module 3 DT-Drive Test Parameters

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