The following subclauses describe how to derive generic QoS parameters from IEEE Std 802.11 link measurement parameters. This derivation relies on incremental values of counters as specified in the IEEE Std 802.11.
Note that the parameters are unicast parameters that are unrelated to multicast traffic.
Packet loss rate
To calculate the packet loss rate (PLR), one uses Equation (1).
According to IEEE Std 802.11, a packet is a MAC user data packet or MAC service data unit (MSDU).
The PLRMSDU can be derived from the Transmit Stream/Category Measurement Report using Equation (2).
Packet error rate
The packet error rate (PER) can be calculated using Equation (3).
Unlike for PLR, this parameter is only defined for the IEEE 802.11 MPDU. The PER can be derived from the STA Statistics Report information element using Equation (4).
Average transfer delay
In IEEE Std 802.11k, the transmit delay (MSDU delay) is defined as follows:
Transmit delay (MSDU delay): The delay shall be measured from the time the MSDU is passed to the MAC sublayer until the point at which the entire MSDU has been successfully transmitted including receipt of the final ACK.
If the average MSDU transmit delay is used for the IEEE 802.21 average transfer delay, it can be derived from Transmit Stream/Category Measurement Report.
Packet transfer delay jitter
Using the IEEE 802.21 definition of “the standard deviation of the delay over a population of interest,” the IEEE 802.11 MAC sublayer provides the Transmit Stream/Category Measurement Report and measurement parameters to calculate the standard deviation of delay.