MCPTT access time values in private calls

[SAAFISalwa]

Hello,

I wanted to compare the average MCPTT access time values in private calls in three different coverage and sidelink mode scenarios (i.e., in-coverage UEs with sidelink mode-1, in-coverage UEs with sidelink mode-2, and out-of-coverage UEs with sidelink mode-2).

I found that in in-coverage UEs with sidelink mode-1 and out-of-coverage UEs with sidelink mode-2 scenarios, the average access time values are around 80 ms (for a sidelink period of 40 ms). However in the in-coverage UEs with sidelink mode-2 scenario, the average values are around 500 ms for the same sidelink period.

Is there an explanation for this gap that can be related to sidelink configurations?

Thanks in advance for your thoughts.

PS: for in-coverage UEs with sidelink mode-2 and out-of-coverage UEs with sidelink mode-2, I used the "Fixed" scheduling method with the same KTRP, MCS, and RB size values.

[wdgj]

Hi,

It sounds like for the in-coverage/mode-1 and out-of-coverage/mode-2 scenarios the 80 ms is as expected for simple request-response.

However, for in-coverage/mode-2 a 500 ms access time is possible when there is a considerable amount of loss. So the first thing you could check and compare are the "mcptt-msg-trace.txt" trace files to see if this is true. Also, for both mode-2 scenarios, what is the difference that makes your UEs either in-coverage or out-of-coverage with your scenario definition?

[SAAFISalwa]

Hi,

Ok, thanks. I will check the trace files.

Well, in terms of scenario definition, the main difference between the two scenarios you mentioned is that since there is no eNB in the out-of-coverage situation then channel setup (freq and PLM mainly) and initialization should be performed explicitly in the scenario.

Before running the simulations, I thought that the two scenarios with sidelink mode-2 will have approximately the same results but after I got different ones that's when I started questioning about the possible impact of the network coverage presence (i.e., eNB definition).