X.1 Maximum Packet Loss Rate (Max. PLR) for Speech

26.1143GPPIP Multimedia Subsystem (IMS)Media handling and interactionMultimedia telephonyRelease 18TS

Based on the 3GPP EVS Selection and Characterization results that included AMR-WB, AMR-WB with G718IO, and EVS codec, this clause provides an example set of Max. PLR operating points that the terminal may indicate to the PCRF/PCF.

X.1.1 Max. PLR recommendation without Application Layer Redundancy

Table X.1 provides example Maximum PLR operating points based on the EVS Selection and Characterization experiment results in TR 26.952 [168] and TR 26.959 [169].

Table X.1: Example Maximum End-to-end Packet Loss Rate (PLR) per link for AMR-WB and EVS

Codec	Robustness Parameter	Maximum End-to-end Packet Loss Rate
AMR-WB	Normal	1.5%
AMR-WB/G718 IO, EVS AMR-WB IO	Medium	3%
EVS WB, SWB	High	6%
EVS WB, SWB Channel Aware	Extreme High	9%

X.1.2 Max. PLR recommendation with Application Layer Redundancy

Application layer redundancy can work in conjunction with any of the aforementioned codec modes in Table X.1.

Table X.2 provides example Maximum PLR operating points with and without application layer redundancy applicable to EVS codec based on informal objective and subjective results in Annex A of TR 26.959 [169].

The example in Table X.2 includes 100% application layer redundancy with offset 2, resulting in (2 x Bitrate). It should be noted that the relationship to path loss when operating at twice the bit rate (with 100% application layer redundancy) is not accounted in the Max. PLR recommendation in Table X.2.

Table X.2: Example Max. End-to-end Packet Loss Rate (PLR) with application layer redundancy for EVS codec

Codec	Robustness Parameter	Maximum End-to-end Packet Loss Rate
No application layer redundancy, EVS at bitrate of R kb/s	–	X %
With 100% application layer redundancy, EVS at bitrate of 2xR kb/s, Offset = 2.	–	X + (2 to 5) %