Query on Ofono Architecture for multiple RATs

Query on Ofono Architecture for multiple RATs

[Naresh Mehta]

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Dear Ofono team,

Lets suppose that I have a modem which implements various radio access
technologies like CDMA, WCDMA,  GSM, LTE, etc. The questions I have
are:

- How should this modem look like inside Ofono and be exposed outside of Ofono?
- Do you expect to have separate modem drivers for CDMA, WCDMA/GSM and
LTE or a single driver covering these varied RATs would be accepted?
- Can there be multiple atoms to support the same functionality in
various RATs (like SMS or emergency calls) or we can modify one atom
to support all the RATs?
- I guess connman needs to know of the different connections such a
modem supports and trigger them accordingly? How might this
functionality look like?
- Can the Ofono DBus API differentiate between various RATs based on
parameters or some new messages needs to be defined if we use a single
modem driver for multiple RATs?

Please advise. Any pointers/suggestions would be of great help.

-- 

BR; Naresh

visit me at:
http://www.naresh.se/

Re: Query on Ofono Architecture for multiple RATs

[Marcel Holtmann]

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Hi Naresh,

> Lets suppose that I have a modem which implements various radio access
> technologies like CDMA, WCDMA,  GSM, LTE, etc. The questions I have
> are:
> 
> - How should this modem look like inside Ofono and be exposed outside of Ofono?
> - Do you expect to have separate modem drivers for CDMA, WCDMA/GSM and
> LTE or a single driver covering these varied RATs would be accepted?
> - Can there be multiple atoms to support the same functionality in
> various RATs (like SMS or emergency calls) or we can modify one atom
> to support all the RATs?

so what you have is CDMA/EVDO on one side and UMTS/GSM/LTE on the other.
I haven't seen any modem supporting both types at the same time. So
CDMA/EVDO is a separate modem and so is UMTS/GSM/LTE. For these modems
you can RAT selection. For example ISI and also HSO have support for RAT
selection on UMTS/GSM. No LTE since I haven't seen any hardware for it
so far.

> - I guess connman needs to know of the different connections such a
> modem supports and trigger them accordingly? How might this
> functionality look like?

Nope. ConnMan plays pretty much stupid here. Only oFono cares about the
differences.

> - Can the Ofono DBus API differentiate between various RATs based on
> parameters or some new messages needs to be defined if we use a single
> modem driver for multiple RATs?

See my comment above and look at the description of the RAT interface we
already have.

Regards

Marcel