HSDPA Reporting of Channel Quality Indicator Measurement Description

NOTE

The test set allows you to collect up to 99000 UE reported CQI values and 99000 filtered ACK/NACK responses in Reporting of Channel Quality Indicator measurement. If both parameters are set to their maximum value of 99000, this measurement can take over 24 minutes to complete.

3GPP TS 34.121 9.3.1 states "The reporting accuracy of channel quality indicator (CQI) under AWGN environments is determined by the reporting variance and the BLER performance using the transport format indicated by the reported CQI median."

The Reporting of Channel Quality Indicator measurement consists of two main parts, which run in sequential order:

    Part 1: CQI Variance test

    Part 2: Block Error Ratio (BLER) versus CQI Sense

For the CQI Variance test (Part1), the downlink signal is configured according to the transport format that corresponds to the CQI value set in the Starting Downlink TF CQI (default value is 16). This is regardless of any CQI values reported by the UE. The test set collects the CQI reports every 2 ms and then, once it collects the Number of CQI Reports to test , it calculates the Median_CQI based on the collected data. If the CQI Variance test it is not within ۬ of the median CQI value then the entire Reporting of Channel Quality Indicator measurement fails and the measurement does not perform the BLER versus CQI Sense test (Part 2).

For the BLER versus CQI Sense test, the downlink signal is sent using the transport format that corresponds to the Median_CQI calculated from the CQI Variance test. The test set continues to collect the associated ACK, NACK, and statDTX responses to any transmitted HSDPA blocks. The responses are filtered as described in 3GPP TS 34.121 9.3.1.4.2 step 6.

The test set collects the responses until the number of filtered responses reaches the Number filtered ACK/NACK responses to test parameter, and then calculates the filtered HSDPA BLER from the filtered responses ( Filtered BLER (%) ). Note, this is the completion of the first half of the BLER versus CQI Sense test. The second half is dependent on the Filtered BLER (%) result that was obtained using the Median_CQI. The second half of the BLER versus CQI Sense testis performed as follows:

• If the Filtered BLER (%) based on the Median_CQI is less than the Filtered BLER for initial CQI sense decision parameter (default is 10%), the test uses the transport format according to the Median _CQI+2 to gather filtered responses (until the number of filtered responses reaches the Number filtered ACK/NACK responses to test ) and then recalculates the filtered HSDPA BLER. If the filtered HSDPA BLER based on the Median _CQI+2 is greater than or equal to the Filtered BLER for PASS/FAIL: Median_CQI+2 parameter, then the UE passes the BLER versus CQI Sense test, and the BLER versus CQI Sense test is complete. Otherwise,
• If the Filtered BLER (%) based on the Median_CQI is greater than or equal to the Filtered BLER for initial CQI sense decision parameter (default is 10%), the test uses the transport format according to the Median _CQI-1 to gather filtered responses (until the number of filtered responses reaches the Number filtered ACK/NACK responses to test ) and then recalculates the filtered HSDPA BLER. If the filtered HSDPA BLER based on the Median _CQI+1 is less than the Filtered BLER for PASS/FAIL: Median_CQI-1 parameter, then the UE passes the BLER versus CQI Sense test, and the BLER versus CQI Sense test is complete.

Reporting of Channel Quality Indicator Measurement Parameters

• Starting Downlink TF CQI

  Sets the transport format of the downlink signal used during the CQI Variance test (Part 1 of the Reporting of Channel Quality Indicator measurement).

• Number of CQI Reports to test

  Sets the number of CQI reports to be gathered in the CQI Variance test (Part 1 of the Reporting of Channel Quality Indicator measurement).

• Percentage of CQI values within range

  Sets the percentage of values that must be in the range Median_CQI-2 to Median_CQI+2 used during CQI Variance test (Part 1 of the Reporting of Channel Quality Indicator measurement).

• Number filtered ACK/NACK responses to test

  Sets the number of filtered ACK/NACK responses to be gathered in the BLER versus CQI Sense test (Part 2 of the Reporting of Channel Quality Indicator measurement).

• Filtered BLER for initial CQI sense decision

  Sets the filtered HSDPA BLER ratio to use to make the CQI sense decision. That is, this parameter sets the filtered HSDPA BLER ratio that controls whether to use Median_CQI+2 or Median_CQI-1 is used for the second half of the BLER versus CQI Sense test.

• Filtered BLER for PASS/FAIL: Median_CQI-1

  Sets the filtered HSDPA BLER ratio used to determine the pass/fail result for the Median_CQI-1 sense direction during the BLER versus CQI Sense test (Part 2 of the Reporting of Channel Quality Indicator measurement).

• Filtered BLER for PASS/FAIL: Median_CQI+2

  Sets the filtered HSDPA BLER ratio used to determine the pass/fail result for the Median_CQI+2 sense direction during the BLER versus CQI Sense test (Part 2 of the Reporting of Channel Quality Indicator measurement).

• Measurement Timeout

  See Measurement Timeouts . If you set Measurement Timeout to On , ensure that the Measurement Timeout value is greater than the time the measurement needs to measure the desired Number of CQI Reports to test .

Reporting of Channel Quality Indicator Measurement Results

Since the Reporting of Channel Quality Indicator measurement consists of two parts, there are separate results reported for each part, including a Pass/Fail result for each part and then an overall Pass/Fail result for the entire measurement.

The CQI Variance test is performed first which provides the Part 1: CQI Variance test results. Then the BLER versus CQI Sense test is performed which provides the two sets of results that are at Median_CQI and either Median_CQI+2 or Median_CQI-1 (depending on the filtered HSDPA BLER result).

Part 1: CQI Variance Results.

• Downlink TF CQI

  This result indicates which transport format was used on the downlink by displaying the corresponding CQI value. The CQI value is an index into the CQI tables specified in 3GPP TS 25.214, which are separated based on the UE category and is characterized by the Number of Active HS-PDSCHs, Transport Block Size, Modulation Type, UE IR Buffer Size (see HSDPA RB Test Mode Setup for more information on these parameters)

• CQI Reports

  This result is the total number of CQI reports gathered during the CQI Variance test (Part 1 of the Reporting of Channel Quality Indicator measurement).

• Median_CQI

  This value is the Median CQI , as specified by 3GPP TS 34.121 9.3.1.4.2 step 4. The CQI report distribution generated by the test set during the CQI Variance test can be obtained using the GPIB query: "FETCh:HRCQuality:VARiance:CQIReports:DISTribution?" .

• CQI in Range (%)

  This result is the percentage of CQI values reported from the UE that are in the range of Median_CQI-2 to Median_CQI+2 .

• Pass/Fail

Part 2: BLER versus CQI Sense

• Downlink TF CQI

  This result indicates which transport format was used on the downlink by displaying the corresponding CQI value. The CQI value is an index into the CQI tables specified in 3GPP TS 25.214, which are separated based on the UE category and is characterized by the Number of Active HS-PDSCHs, Transport Block Size, Modulation Type, UE IR Buffer Size (see HSDPA RB Test Mode Setup for more information on these parameters)

• Median CQI

  This is determined the same way as that the Median_CQI is found in the CQI Variance test.

• statDTXs

  The number of statistical DTXs received.

• Filtered ACKs

  Number of filtered positive acknowledgments. (The responses are filtered as described in 3GPP TS 34.121 9.3.1.4.2 step 6.)

• Filtered NACKs

  Number of filtered negative acknowledgments. (The responses are filtered as described in 3GPP TS 34.121 9.3.1.4.2 step 6.)

• Filtered ACKs+NACKs

  The sum of the number of filtered positive acknowledgments and filtered negative acknowledgments. (The responses are filtered as described in 3GPP TS 34.121 9.3.1.4.2 step 6.)

• Filtered BLER (%)

  Filtered HSDPA BLER result.

  

Key 3GPP Tests Performed Using the Reporting of Channel Quality Indicator Measurement

3GPP TS 34.121 9.3 Reported Channel Quality Indicator

Reporting of Channel Quality Indicator Input Signal Requirements

• The expected power into the test set must be set in order to maintain a link with the UE. This is done using the UE Target Power setting or by using manual receiver control and specifying the expected power level. See Receiver Control .
• Frequency: 800 to 1000 MHZ, 1700 to 1990 MHz
• Input level: -61 dBm to +28 dBm

Other Things to Consider

The Reporting of Channel Quality Indicator measurement is aborted and restarted when the following test set parameters are changed while the measurement is active: Operating Mode , Measurement Frequency , Channel Type , RB Test HS-DSCH Configuration Type , or any changes to the System Configuration screen.

This measurement is triggered via the HS-DPCCH, and therefore you must have an RB Test Mode - HSDPA connection established (Channel Type 12.2K +HSDPA) in order for the test set to perform this measurement. Active Cell is the only Operating Mode currently supported.

Error messages are displayed when the following parameters are not set up correctly: CQI Repetition Factor, Measurement Power Offset, and UE IR Buffer Size. There are also several settings that must be set in order to comply with 3GPP TS 9.3.1.

During this measurement, the test set has ACK/NACK handling set such that new data is sent from the UE regardless of the previous response from the UE (ACK, NACK or DTX).

Since the CQI Variance and both parts of the BLER versus CQI Sense run sequentially, the intermediate count only applies to the part of the measurement that is currently running.

There are several parameters that are not specific to this measurement that must be set in order to comply with 3GPP TS 34.121 9.3.1. See Parameters that Affect the HSDPA Reporting of Channel Quality Indicator Measurement .

Related Topics

Manual Operation: How Do I Make an HSDPA Reporting Channel Quality Indicator Measurement?

Programming an HSDPA Reporting of Channel Quality Indicator Measurement

HSDPA Reporting of Channel Quality Indicator Troubleshooting