1. Triggered QoS Measurements
January 2005
doc.: IEEE /0294r0
January 2005
Triggered QoS Measurements
Date:
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Simon Black et al, Nokia
Simon Black, Nokia

2. January 2005
doc.: IEEE /0294r0
January 2005
Abstract
This presentation introduces the concept of triggered autonomous measurements on QoS streams.
Simon Black et al, Nokia
Simon Black, Nokia

3. QoS Measurements – Current Situation
January 2005
QoS Measurements – Current Situation
TGk has received several submissions proposing to add QoS metrics to the 11k draft
Useful to collect QoS transmission statistics to help optimise performance
QoS Metrics Measurement provides a good starting point
QAP can request QoS metrics, or set up periodic reporting using a repeated measurement request
Simon Black et al, Nokia

4. QoS Measurements - Observations
January 2005
QoS Measurements - Observations
QoS metrics measurement is not invasive in normal operation
Does not involve measurement on a non-serving channel
Measurement data is particularly useful when there is something to report
For example, a QSTA experiences lengthening transmission delay, or multiple transmission failures
Repeated measurements may successfully report this, but
Will also report when conditions are fine – wasting bandwidth and QAP processing
May miss periods of difficulty if measurement is not continuous
Autonomous measurements might help, but
The QAP has no control over what the QSTA reports so can’t rely on receiving useful data
Simon Black et al, Nokia

5. Triggered Measurements
January 2005
Triggered Measurements
What is needed is a QoS measurement scheme that
Runs continuously at a QSTA – regardless of measurement requests of other types
Only reports when needed
Reports before things get too bad
The QAP has control over and can rely on
The QoS metrics measurement provides the right report content
All that is needed is a triggering mechanism with parameters controlled by the QAP
Simon Black et al, Nokia

6. Triggered QoS Measurement Overview
January 2005
Triggered QoS Measurement Overview
QAP enables autonomous measurement and sets up trigger conditions in measurement request
Autonomous measurements disabled by default
Set up on a per traffic stream as a triggered autonomous measurement
QSTA may refuse to accept autonomous measurement by using the refused bit in a measurement report
QSTA sends measurement report if trigger conditions are met
Measurement Report is a QoS Metrics Report for the traffic stream – exactly as for a requested measurement
QAP has control of the measurement and therefore can effectively use the data
Measurement disabled by
QAP sending a measurement request turning off the measurement, or
Stream is deleted (e.g. QSTA disassociates)
Simon Black et al, Nokia

7. Triggered QoS measurements in practice
January 2005
Triggered QoS measurements in practice
Define new fields for the QoS Metrics Measurement Request frame to enable the QAP to enable/disable triggered reporting conditions for the traffic stream
Allow trigger conditions to be set by including a QoS Metrics measurement request when enable and report bits are set (enabling autonomous reporting)
The Measurement Duration in the request specifies the averaging period for some triggers
If trigger condition met, QSTA sends an autonomous QoS Metrics Report with QoS metrics for the link
Simon Black et al, Nokia

8. Trigger Conditions Proposed Trigger thresholds
January 2005
Trigger Conditions
Proposed Trigger thresholds
Number of MSDU failures in the specified period
Number of consecutive MSDU failures
Consecutive MSDUs delayed by more than a threshold
QAP enables each trigger and sets the appropriate threshold for reporting
Simon Black et al, Nokia

9. Compared to QoS Repeated Measurements
January 2005
Compared to QoS Repeated Measurements
Reports only generated when conditions of interest occur – saves bandwidth and QAP processing
Not subject to requested measurement precedence rules – can run continually at the QSTA even if other measurements performed
QAP enables and disables measurement rather than setting an arbitrary number of repetitions
Simon Black et al, Nokia

10. Compared to Existing Autonomous Measurements
January 2005
Compared to Existing Autonomous Measurements
QAP has control of the measurement and therefore can effectively use the data
Standardized reporting conditions
Simon Black et al, Nokia