Band optimization for different power profiles

[gjoasen]

In the nRF9160 AT Commands Reference Guide the description of the %PERIODICSEARCHCONF states that if the band_optimization paramter is set to 1 then "Use default optimizations predefined by the modem. Predefinition depends on the active data profile, which can be configured with %XDATAPRFL". However, I am not able to find any information about what the different data profiles acutally have predefined. The search patterns provided for the different data profiles have the band_optimization set to 1, so that does not help. Could you please provide the default optimization for the different data profiles?

[Charlie]

Hi Gjert,

Please see the following description:

Since v1.3.1 MFW introduced new command %PERIODICSEARCHCONF which can be used for configuring the idle time between the searches when in limited service or out of coverage. In earlier releases this was not possible but it was possible to configure data profile with %XDATAPRFL command. The data profile affected also to the periodic search configuration in use. The following citation is from the Nordic's AT command documentation and it represents the periodic search configurations used by default with each data profile:

Ultra low power:
AT%PERIODICSEARCHCONF=0,0,0,1,"0,10,40,,5","1,300,600,1800,1800,3600"
Low power:
AT%PERIODICSEARCHCONF=0,0,0,1,"0,10,40,,5","1,300,600"
Normal:
AT%PERIODICSEARCHCONF=0,0,0,1,"0,10,40,5,15","1,60,90,300"
Performance:
AT%PERIODICSEARCHCONF=0,0,0,1,"0,10,40,5,15","1,60,90"
High performance:
AT%PERIODICSEARCHCONF=0,0,0,1,"1,10","0,10,40,,15"

These configurations have been pretty much the same in the earlier MFW releases, too. One difference I can mention is that I think for Ultra low power data profile the longest idle time was at first 30 minutes, but it was extended to 60 minutes later. I think any other differences between the latest releases were minor and basically only caused by the fact that the search configuration is not anymore a static table in our implementation but is calculated based on the above configurations. Our target was to achieve with the configuration method similar default behaviour to what we earlier had with the static tables (the difference being that clients can do the configuration by themselves according to their use case - if they want to), which is why there should only be minor differences in the default functionality, i.e. when %PERIODICSEARCHCONF has not been used.

If periodic searches play an important role in your use case, I suggest getting familiar with the %PERIODICSEARCHCONF and using the latest MFW version that has the command implemented.

Best regards,

Charlie

[gjoasen]

Hi Charlie

My question is not about the period between searches, but about the band_optimization parameter passed to PERIODICSEARCHCONF. This parameter controls how often a all band search is carried out. In the periodic search configurations you provided for the different data profiles, the band_optimization parameter is set to 1 for all of them. According to the documentation this means:

"Use default optimizations predefined by the modem. Predefinition depends on the active data profile, which can be configured with %XDATAPRFL"

But the documentation does not say what the band optimization is for the different profiles. 

Cheers,

Gjert

[Charlie]

Hi Gjert,

Checked with our modem development team and got the following reply:

The default band optimization algorithm depends on many factors (e.g. cell history, location, etc.) and the details are not public information we can share.

We can say that the default configuration is something we have found to be a well-working configuration and all approval/acceptance tests etc. are passed with the normal power level without additional configuration for periodic searches. The possibility to configure the periodic searches and the band optimization in it is to provide a method to save more power on the cost of the time it takes to find a suitable cell again, or in contrary, to use more power to make it faster to find a suitable cell again. Suitable band optimization configuration depends on the use case.

Best regards,

Charlie