Re: Monitor current technology

[Denis Kenzior <denkenz@gmail.com>]

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Hi Daniel,

> This series adds a new property to DCM to export the
> current technology used.
> 

So I've been reviewing your patches and also thinking about solving this 
technology problem nicely.  First a bit of background on the state of hardware 
today:

27.007 (The Standard):
- +CREG - Reports CS netreg parameters, including tech.
- +CGREG - Same as above for PS netreg parameters
- +CPSB - Reports the current packet switched bearer for a given context.  
Presumably this can change quite dynamically during a GPRS session.

MBM:

- *EREG - Reports CS netreg parameters, including status/lac/ci and tech (0 - 
GSM, 2 - UMTS).  Essentially same as CREG with addition of tech reporting.
- +CGREG - Reports PS netreg parameters, including status/lac/ci/tech (per 
27.007)
- *ERINFO - Reports current Cell capability, gprs/egprs/umts/hsdpa, nothing 
new over +CGREG
- *EPSB - Reports current packet switched bearer.  This is only available on 
recent devices.  This one is supposed to tell the actual packet bearer and 
acts similar to 27.007 +CPSB.  The state depends on the link state, and tends 
to oscillate between 0 (no bearer) and some bearer quite often, even when 
context is active.

STE:

- Same as MBM with *ERINFO seemingly missing.

ISI:

I'm not an ISI expert, but here's what I gleamed from a quick look at that 
driver:

- Reports RAT (gsm/gsm compact/umts) and current cell capability (edge / no 
edge, hsupa availability, hsdpa availability)
- No equivalent of +CPSB

Huawei:

- ^MODE and ^SYSINFO can report current mode.  This seems to be the same as 
cell capability on other devices.

HSO:

- One of the weird ones.  There is no tech reporting through CREG/CGREG at all
- The current access technology (gsm / umts) is reported through OSSYSI
- Edge / no edge capability is reported through OCTI
- UMTS/HSDPA/HSUPA are reported through OUWCTI.  Unfortunately OUWCTI is not 
always reported properly and can change within the cell when the context is 
activated / deactivated.  Some firmware does not report / support OUWCTI at 
all.

The consensus among the hw seems to be to report the capability of the 
currently selected cell, with the exception of HSO, which just acts stupidly.

So my current thinking is to drop any Tech reporting in gprs atom for now.  At 
least until we actually find a usecase for EPSB/CPSB style reporting.

HSO OUWCTI reporting is still an issue.  I'd be glad to hear some alternate 
ideas about how to integrate it properly at this point.

Regards,
-Denis