NRF9160 eDRX Online Power Profiler

[cri13]

Hello,

When using eDRX alone and without DATA (eDRX=81,92 sec, no PSM, no data transmittion,iDRX PDCCH = 1), it's showing an average current of 17,84 uA. This value is similar that we can found in the datasheet but on the graph i don't see the PTW time that could be a value between 2,56s and 40,96s.

If I increase iDRX PDCCH to 256, the length of the iDRX range grow up from 104ms to 355ms. It's very different of the PTW range. 

Why?

Thanks.

[Stian Røed Hafskjold]

Hi, it's not possible to change the PTW in the OPP, it defaults to one paging occasion per DRX event. We are working on implementing this. As a workaround you can change the eDRX interval, e.g. if you halve the interval, it will be equivalent to doubling the number of paging occasions.

[cri13]

Hello,

When using RRC iDLE mode without DATA (cDRX=5,12sec, cDRX on = 8 ms, cDRX inactivity timer = 100ms, no PSM, 100 data upload every 120s , RRC inactivity timer = 10s  iDRX PDCCH = 1), it's showing a cDRX iDLE current of 26,82 uA and equal to the eDRX idle current.

is it normal??

Thanks.

[Stian Røed Hafskjold]

If you have no data or PSM TAU events, the modem will never wake up and will stay in RRC idle forever.

In general, the DRX average current in RRC idle and RRC connected mode can be similar if the DRX intervals and RX window length match.

[cri13]

Hello,

I do a mistake on my request. Data are really sending.

My question should be :

 Why in RRC iDLE mode with data (cDRX=5,12sec, cDRX on = 20 ms, cDRX inactivity timer = 100ms, no PSM, 100 data upload every 120s , RRC inactivity timer = 10s  iDRX PDCCH = 1)  there are a lot of scenarii:

•  Synchro
• RRC setup
• Transmit Data
• DRX inactivity timer
• cDRX mode (cDRX event + cDRX)
• DRX incativity timer
• iDRX.

whereas in RRC mode with data (cDRX =5,12s, cDRX on = 20 ms, no PSM) there are only two steps:

• Transmit data
• cDRX mode (cDRX event + cDRX ) ???

And something more suspicious is the average current for these two cases:

• in RRC with iDLE mode < I > = 598µA.   ( RRC iDLE ??)
• in RRC mode                   < I > = 353µA.   (RRC connected ??)

Normally, the current in the RRC iDLE mode shouldn't be lesser than in the RRC mode?

I'm wondering if i don't do a mistake between the two cases.

What do you think?

[Stian Røed Hafskjold]

Hi, this looks normal. In RRC idle the modem will attach to the network (go from RRC idle to RRC connection) every time data is transmitted; this will add to the average current consumption.

There are two reasons why your scenario with only RRC connected probably will not work.

1. RRC connection may be released after a few seconds automatically by the network (RRC connected -> RRC idle automatically)
2. The cDRX interval is decided by the network (cannot be requested by the modem), and it is usually a lot shorter than 5.12 seconds. So the RRC connected average current is usually much higher.