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Radio Performance Measurments Based on IuB Monitoring

Chip Energy over Noise (Ec/No)

In CDMA systems, becasuse of the frequency reuse factor 1, there is a need for

a power level independent quality criterion of received signals. For donwlinkchannels this is the Chip Energy over Noise (Ec/No). The EcNo is not really a

UE measurement, rather it is a calculated value. It is defined as ratio between

received signal code power RSCP and UTRA carrier strength (UTRA carrier

RSSI). A UE reports the EcNo of CPICH (CPICH Ec/No) of serving and neighbor

cells. Obviously this is done via RRC protocol. Two information elements

contain Ec/No measurement results: Measured Results on RACH and Cell

Measured Results. Measured Results on RACH contains measurements

done by UE in idle mode or CELL_FACH state. These measurements are used

by the RNC for open loop power control on FACH. The following messages

may contain this parameter:

RRC CONNECTION REQUEST (for idle UE)

INITIAL DIRECT TRANSFER and UPLINK DIRECT TRANSFER(for CELL_FACH mode only)

CELL UPDATE and URA UPDATE (conditional, depends onmeasurement configuration in SIB11/SIB12)

MEASUREMENT REPORT (CELL_FACH mode only)

The information element Cell Measured Results occurs in the

MEASUREMENT REPORT message only. The reporting scenarios for Ec/No

are also applicable for RSCP and Pathloss reporting. The UE may use Ec/No

for event triggered reporting.

Productivity Tips:

Ec/No can be measured alsothrough Drive Test but using aIub interface monitoring ap-

proach provides more reliablestatistics sampling, faster ac-cess to information and reducedcost of operations In somecases RNC Traces can also pro-vide this vale but requiring ex-tensive configuration

NSA Trend-Navigate CPTCell Radio Analysis showsthe Ec/No values from intra-frequency and inter-frequencyMeasurement Reports andinitial Ec/No from RRC

Connection Request

NSA Trend-Navigate CPTProblematic Cell providesEc/No threshold for violationset to -14dBm (Configurable)

NSA Call Analysis allows toanalyze detailed Ec/Novalues over single calls

Quick Guide | www.tektronixcommunications.com/UTRAN

UMTS UTRAN Troubleshooting Quick Guides

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Troubleshooting Tips:

Look for Ec/No to troubleshoot issues related to DOWNLINK SIGNAL

QUALITY and/or to check if you are providing the right balance of

POWER and QUALITY to your users

Contact Tektronix Communications:

Please visit www.tektronixcommunications.com

About Tektronix Communications:

Tektronix Communications provides network

operators and equipment manufacturers around

the world an unparalleled suite of network

diagnostics and management solutions for fixed,

mobile, IP and converged multi-service networks.

This comprehensive set of solutions support a

range of architectures and applications such as

LTE, fixed mobile convergence, IMS, broadband

wireless access,WiMAX, VoIP and triple play,

including IPTV. Tektronix Communications is

headquartered in Plano,Texas.

Learn more about the company's test,

measurement and network monitoring solutions by

visiting www.tektronixcommunications.com.

For Further Information:

Tektronix Communications maintains a

comprehensive, constantly expanding collection of

application notes, technical briefs and other

resources to help engineers working on the cutting

edge of technology.

Please visit www.tektronixcommunications.com

Copyright , Tektronix.All rights reserved.Tektronix products are covered by U.S. and foreign patents, issued andpending. Information in this publication supersedes that in all previously published material. Specification and pricechange privileges reserved. TEKTRONIX and TEK are registered trademarks of Tektronix, Inc. All other trade namesreferenced are the service marks, trademarks or registered trademarks of their respective companies.

07/11 | CMW-27190-0

Want to know more?

NOTE : Ec/No and Ec/Io are now considered as equivalent terms. In

CDMA theory, No covers all wideband power including wanted and

unwanted signals, whereas Io means only interfering signals. Under

normal load the difference between Io and No is neglectable.

Chip Energy over Noise (Ec/No Ec/Io)Received energy per single bit divided by power density on the radioband. Calculated as RSCP / UTRA carrier RSSI. Only reported fordonwlink measurements by UE (RRC).

unit: dB range/step: -24 dBm ... 0 dBm / 0.5 dBm calculation: CPICH Ec/No = CPICH Ec/No / UTRA carrier RSSI coded as: INTEGER (0..49) [RRC]

Reported value Range Unit

CPICH_Ec/No_00 CPICH EcIo < -24.0 dB

CPICH_Ec/No_01 -24.0 CPICH EcIo < -23.5 dB

CPICH_Ec/No_02 -23.5 CPICH EcIo < -23.0 dB

CPICH_Ec/No_03 -23.0 CPICH EcIo < -22.5 dB

... ... ...

CPICH_Ec/No_47 -1.0 RSCP < -0.5 dB

CPICH_Ec/No_47 -0.5 RSCP < 0 dB

CPICH_Ec/No_49 0 RSCP dB

Benchmark: Desired value is for single call between -3 dBm and -9dBm, for ActiveSet Update ~ -10dBm. An high RSCP at low Ec/No (e.g. -70dBm and low EcNO e.g.

-15dB ) means Downlink Interference

-124 dBm

RSCP

0 EcNO -24.5dB

CoverageIssue

OK DownlinkInterference

Cell Edge

When Ec/No value is out of

range, Downlink quality is

impacted: call drops.

The lower the value,

the lower the Signal quality