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<< A broader question which might be silly >>
It is not silly. Essentially you are asking a question that carriers have been asking themselves and discussing with each other and with their infra and handset vendors over the last 45 days.
The answer to this question relates to their timing for full scale commercial launches of their already commercially live networks, and sign off on integration testing of handsets they have on order, allowing their OEMs to ramp production.
<< If PBCCH is not used, isn't the whole packet-based nature of GPRS compromised? >>
No. GPRS is a bearer service for packet data, with or without PBCCH/PCCCH.
We are talking about CONTROL channels here. PBCCH/PCCCH are EXTRA PACKET CONTROL channels (in addition to BCCH/CCCH non-packet control channels for packet data - which is already implemented in launched and live GPRS networks) that allow optimization of a GPRS network and minimize congestion on that network when mass deployment is achieved.
<< is DCCM really GPRS? >>
It would have been if acted upon but Dual Control Channel Mode (DCCM/A) is not anything (if my understanding of the status of the joint Nokia/Ericsson/Siemens/Vodafone proposal is correct). The proposal to amend the 'R97' standard (finalized in 1998 and amended since) with an optional dual-mode capability was withdrawn as I understand it last Monday following a week of discussion in the GERAN TSG meeting.
Evidently PBCCH contains an enormous amount of functionality that can be divided into smaller features, but infrastructure that is currently being provided does not offer full PBCCH functionality and operators for the most part have not turned PBCCH on. IOT in the field is being conducted using BCCH/CCCH and available handsets have not been tested against a full, live, PBCCH implementation, and the issue that this created was the possibility of interworking problems with future PBCCH features as they are implemented in whole or in part.
The e-mail reflector that Ilmarinen linked provides good background for the issues that faced carriers and vendors when they met in Naantali last week and this week.
Message 16271581
Evidently by Monday a compromise was reached that allows vendors to supply a basic agreed upon level of requisite functionality in a GPRS handset with respect to packet signaling, and advanced "optional" features (leading to full compliance with the GPRS standard) that can be incorporated over time.
This evidently will allow carriers to proceed with IOT while bringing PBCCH/PCCCH functionality forward on the network side without materially postponing commercial launches of GPRS networks.
Vendors will in turn make decisions about whether or not to ramp production (and when) of GPRS handsets to avoid having to recall at a later date when PBCCH/PCCCH is fully implemented and turned on.
... at least that is how I understand it. No complete summary of what has transpired on this subject this week has been made public so far as I know but some research notes are evidently starting to circulate from sources other than CSFB and WitSoundview (where I picked up on the issue).
Essentially what has transpired is that competitive vendors and carriers have once again demonstrated that they can work together cooperatively in committee to advance open non-proprietary standards and insure that the resultant technology implementation - regardless of which vendor supplies it - works in optimum and uniform fashion network to network.
Thanks as always to Ilmarinen for the examples and explanations he has provided to those of us who are not deeply technically literate.
If I have stated anything innacurately, I am hopeful he will correct. Maybe he already has since I started this post, but before I completed it (in between phone calls).
Best and have a great weekend.
- Eric - |
