nRF9160 maximum transmit duty cycle

[Gmiddles]

I am curious if there is an inherit maximum transmit duty cycle of either M1 or the nRF9160.  I am asking for this because we need these numbers for SAR test.  Our product will be near the body and the duty cycle will be an important parameter for this test.

[Andreas]

Hi,

 

Unfortunately there is nothing new on this, the max duty cycle is 32/37 and 256/296. How long this lasts for depends on the application and how much data that has to send.

 

Best regards,

Andreas

[Andreas]

Hi,

 

One example calculation. Your case might be slightly different but it should give a ballpark estimate:

1 kbyte user data is transmitted over LTE-M1 uplink.

Assuming 40% higher layer overhead (estimate), and upon various assumption related to physical layer procedures and radio channel, we may estimate that the total time needed for UE to transmit 1 kbyte is about 0.5 second. The UL duty cycle during the transmission period of 0.5 second is 57% (assuming the repetition number for PUSCH is 8 and repetition number for MPDCCH is 2). So, the total UL duty cycle is

 

UL duty cycle (over 30 minutes) is: N * 0.5 * 0.57 / (30 * 60),

where N is the number of user data packets, each of size 1 kbyte, transmitted during the period of 30 minutes.

 

Best regards,

Andreas