Re: [MM 0.6] Plumb up the SPN display-rule bits

[Nathan Williams <njw google com>]

>> +    <property name="DisplayRegisteredNetworkNameAtHome" type="b" access="read" />
>
>
> Quoting from the TS:
> "b1=0: display of registered PLMN name not required when registered PLMN
> is either HPLMN or a PLMN in the service provider PLMN list.
> b1=1: display of registered PLMN name required when registered PLMN is
> either HPLMN or a PLMN in the service provider PLMN list."
>
> I don't think that "DisplayRegisteredNetworkNameAtHome" covers
> everything the property is meant to say. Actually, it hides the main
> purpose of the property, which is the fact that the registered PLMN name
> should be displayed even if the network is not the home network, but a
> network allowed in the PLMN list. E.g. I have a card from the 'Yoigo'
> operator, and when using 2G my phone connects to the 'Movistar'network:
> but my phone still needs to display 'Yoigo' instead of 'Movistar'. The
> fact that the device should display the name of the registered PLMN when
> in the same home PLMN is quite obvious already.
...
> The name "DisplayOperatorNameWhileRoaming" is also not fully clear.
> 'Roaming' means for the modem/phone 'not in the home network', and that
> covers both being in a network allowed in the list stored in the SIM
> card, or really roaming in another not-listed network. Following my
> example before, when I connect to the Movistar network with a Yoigo SIM
> card, I will be reported as being roaming, even if the network is one of
> the allowed networks in the list stored in the SIM card.

I don't think this is right - the "service provider PLMN list",
EF_SPDI, referred to in 31.102 is not the list of all possible
networks to roam on; it's a separate list that exists purely for
fine-tuning this display.

If the card from 'Yoigo' doesn't list 'Movistar', then bit 1 is
irrelevant, we always display 'Movistar', and bit 2 controls whether
we display 'Yoigo' as well. (If the card from 'Yoigo' did list the
'Movistar' PLMN on its (E)HPLMN list, or has it in the EF_SPDI list,
then bit 1 controls whether we need to mention 'Movistar' at all (we
always need to mention 'Yoigo' when on a home network)).

I admit that the inclusion of the EF_SPDI list in the discussion makes
the home/roaming distinction a bit fuzzier (though I have yet to see a
non-empty EF_SPDI list), but I think that's roughly the right
division.

>From Annex A.4 of 22.101:

When registered on the HPLMN, or one of the PLMN Identifications used
for Service Provider Name display:
(i) The SP Name shall be displayed;
(ii) Display of the PLMN Name is an operator"s option by setting the
appropriate fields in the USIM (i.e. the Service Provider name shall
be displayed either in parallel to the PLMN Name or instead of the
PLMN Name).

When registered on neither the HPLMN, nor one of the PLMN
Identifications used for Service Provider Name display:
(i) The PLMN name shall be displayed;
(ii) Display of the SP Name is an operator"s option by setting the
appropriate fields in the USIM.

    - Nathan