RE: PSM + eDRX

Håkon Alseth — Tue, 24 May 2022 10:57:11 GMT

Hi,

[quote user=""]TAU Request with both PSM and eDRX - PSM Granted, but eDRX not Granted on TAU Accept[/quote]

You can only be in one sleep mode at the same time.

[quote user=""]

On my understanding the modem is getting into sleep for 156 seconds after the 5.12 PTW.

How does this RF inactivity sleep differs from a PSM sleep as bellow?

[/quote]

There's two different modes of sleep. PSM is normally used for longer periods than eDRX.

[quote user=""]

Are both sleeps expected to have the same 2.7uA floor level? If not, what would be the floor level for the RF inactivity sleep from eDRX?

[/quote]

Both yes and no. The modem can turn off the clock to the SIM if the SIM supports lower power modes (see here for more info https://infocenter.nordicsemi.com/topic/ps_nrf9160/ip/radio_lte/doc/simif_lte_m/frontpage.html?cp=2_0_0_6_0).

There's a tradeoff between SIM-wear wrt. going into lower power mode, so you usually need to check how many read/write cycles your SIM can handle to ensure that it stays operational for the duration period of the product. Please see this AT command for more info:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/xdataprfl_set.html?cp=2_1_4_13_0

If the SIM is powered on, you'll normally see a idle current of ~20-60 uA from the SIM itself (depends on the type of SIM).

[quote user=""]Would enabling (if possible) both PSM + eDRX would make the modem sleep on a lower floor level during the 156 seconds of the eDRX interval?[/quote]

No, not possible. You're either in eDRX or PSM, not both.

Kind regards,

Håkon