nRF9160 NB-IOT Current Cosumption

[ashokhirpara]

Hi Nordic Support Team,

I am planning to use nRF9160 Customised Board  for NB-IOT Application.

I want to make it battery Operated Device.

As i want to know how Communication will take place like SIM Authentication Time,minimum Time require for NB-IOT communication.Total time period of operation.

During above events how much maximum current will flow for maximum time.

so according that i can able to get battery life for product.

can you suggest how it can be done.

hoping for your kind Support..

[Stian Røed Hafskjold]

Hi, sorry for not giving you an answer on this yet. There are many parameters involved in this so it's hard to give a definite answer. I'm attaching a plot of NB-IOT waking up from PSM and sending 1kB of data:

Yellow is the nRF91 current, and Green is the SIM card current:

First you see network sync, then SIM refresh (green), then RRC setup. authentication, TAU and data upload. The highest peaks are radio TX and the peak current depends on the dBm setting, which changes based on the reception, and the radio band. You can find the peak currents here: https://infocenter.nordicsemi.com/topic/ps_nrf9160/_tmp/alta.nRF9160/autodita/CURRENT/parameters.id_current_modem.html?cp=2_0_0_4_1_0_13

If you wake up from eDRX idle instead of PSM there's less overhead, and the consumption might be a bit lower.

[ashokhirpara]

Thanks For Your Answer.

i have gone through shared link.

can you tell me what will be the my normal active current.

as said during transmission i am considering Peak current.

in between what is the normal current of module.

my peak current is for little time period of communication .

is RRC is my normal active current?

Please Suggest

[Stian Røed Hafskjold]

How often do you want to wake up to send/receive data?

You usually go to RRC idle, and eDRX idle mode after sending data. The sleep current is 7 uA in this mode. The radio listens to the network in intervals so the total current will depend on how often you need to monitor the network, i.e. the latency of the communication.

If you don't need to monitor the network you can use PSM mode. In PSM the sleep current is 4 uA and you can wake up to send or receive data whenever you want, but it's unreachable by the network, so the transfer will be initiated by the UE.

[ashokhirpara]

Thanks For Reply,
As i am using cellular as a alternative option if my first preference is not available.
lets say cellular will stay up for 30 second of operation.

in 30 second operation contains network scanning,registration,data reception and data transmission.
what is the my average transmission, reception current and average current while network registration and authentication.

please consider maximum current consumption scenario,so i can get maximum battery life for same

Please suggest.

Thanks & Regards, 

[Stian Røed Hafskjold]

Hi, sorry for the late response.

Attaching a plot of:

• Modem waking up from offline mode
• Scanning for networks
• Attaching to the network
• Sending 100 bytes of data and staying in RRC connected mode with 320ms DRX intervals (waiting for any response from the network)
• Then goes to PSM (power saving mode, consuming 4 uA)

Complete event:

Scanning:

Connected:

Staying in DRX mode (discontinuous reception), waiting for incoming data. This length is decided by the network and may be longer or shorter than shown here:

PSM mode. Power saving mode. Do not have to scan for the network again upon waking up: