nrf9160 PSM mode strange current profile

RE: nrf9160 PSM mode strange current profile

crasspm — Tue, 09 Mar 2021 14:22:04 GMT

Thanks Jonathan, I'm in contact with my network supplier now to verify. I'll also keep an eye on NBIOT and RAI.

RE: nrf9160 PSM mode strange current profile

JONATHAN LL — Tue, 09 Mar 2021 12:12:35 GMT

Hi,

No, it is sett and decided by the network.
Something you can check out is RAI or release assistant indication but it is only available in NBIOT.
Regards,
Jonathan

RE: nrf9160 PSM mode strange current profile

crasspm — Mon, 08 Mar 2021 15:40:38 GMT

Thanks Jonathan. My lowest sleep current is ~6uA so I'm sure I'm in PSM, my question about whether I'm connecting correctly is more targeted to whether my configuration (PSM timers etc) is to blame for the ~20s of Connected Mode DRX. More importantly, is there any way to reduce this time spent in Connected Mode DRX? I can see that the data transaction is complete (transmit and response receive) before the Connected Mode DRX period, and if I can reduce this period I can save on power.

Thanks!

RE: nrf9160 PSM mode strange current profile

JONATHAN LL — Mon, 08 Mar 2021 08:52:33 GMT

[quote user="crasspm"]Am I connecting correctly?[/quote]

Yes.

When in PSM mode the consumption should be sub 100uA. If you test the UDP sample and measure you will see approximately how low it can go, and compare the results to what you have in your code.

But, not all networks\SIM cards provide PSM so this is something you have to check.

Regards,
Jonathan

RE: nrf9160 PSM mode strange current profile

crasspm — Thu, 04 Mar 2021 14:30:10 GMT

Thanks Jonathan!

Here is the connection code I'm using:

		err = lte_lc_psm_req(true);
		if (err) {
			LOG_ERR("PSM request failed, error: %d", err);
			return err;
		}
		
		err = lte_lc_init();
		if (err) {
			LOG_ERR("LTE link could not be established, error: %d",
				err);
			return err;
		}
                
        err = lte_lc_connect();
		if (err) {
			LOG_ERR("LTE link could not be established, error: %d",
				err);
			return err;
		}

As I understand it, RAI is only available for eDRX, which I am not enabling (in fact, if I do attempt to request RAI I get an error indicating that it isn't available).

Am I connecting correctly? Can I possibly reduce the time spent listening on the PDCCH channel? I would like to be very conservative with power.

Thanks so much for your help so far!

RE: nrf9160 PSM mode strange current profile

JONATHAN LL — Wed, 03 Mar 2021 14:42:16 GMT

Hi,

it is lissening on the PDCCH channel, DRX interval is the space between the pikes. First is TX data (black area), Then RRC connected, then it idles (grey area).

pleas take a look at the UDP sample, it shows you how to use and set up PSM.

In the UDP sample the following is done to enable PSM:

static int configure_low_power(void)
{
int err;
#if defined(CONFIG_UDP_PSM_ENABLE)
/** Power Saving Mode */
err = lte_lc_psm_req(true);
if (err) {
printk("lte_lc_psm_req, error: %d\n", err);
}
#else
err = lte_lc_psm_req(false);
if (err) {
printk("lte_lc_psm_req, error: %d\n", err);
}
#endif
#if defined(CONFIG_UDP_EDRX_ENABLE)
/** enhanced Discontinuous Reception */
err = lte_lc_edrx_req(true);
if (err) {
printk("lte_lc_edrx_req, error: %d\n", err);
}
#else
err = lte_lc_edrx_req(false);
if (err) {
printk("lte_lc_edrx_req, error: %d\n", err);
}
#endif
#if defined(CONFIG_UDP_RAI_ENABLE)
/** Release Assistance Indication */
err = lte_lc_rai_req(true);
if (err) {
printk("lte_lc_rai_req, error: %d\n", err);
}
#endif
return err;
}

Remember to call for PSM before connecting.

Regards,
Jonathan