Peter makes a good point. The rules will allow a device to use channel availability data for as much as 48 hours - it allows that the device must access the database at least once per day, but if it tries and fails it can use the data until 11:59pm of the follow day.
That wasn't the 48 hours I was thinking about though, I was thinking about the paragraph before that: § 15.711 (b)(3)(i) ... Fixed TVBD must adjust their use of channels in accordance with channel availability schedule information provided by their database for the 48-hour period beginning at the time of the device last accessed the database for a list of available channels. So in addition to providing what is available now, plus how things are expected to change over the next 48 hour period. I shouldn't have said "guess" since the requirements for notice from the priority users are greater than 48 hours. Having now discussed it "out loud" so to speak, it really does not need to be two distinct notions. The The "start/end" on a per channel basis provides what you need; and the database has to provide a schedule at the time of request that shows everything from now until now + 48 hours. I also agree enthusiastically with Peter that we should expect changes in the requirements (and that is a guess, but an educated one ;-). Ben > Ben, > FCC rules do assume that a channel assignment if from now until some time > in the future, the current default is 24 hours - unless the device moves. > It is same to assume that the duration will become much shorter > eventually. So "Valid until" is a reasonable proposition. However the FCC > does not preclude a radio from getting a channel list in advance. In many > ways it makes more sense for a device to ask for a new channel list before > it's current list expires so start time might be relevant in this case. > > I don't think the FCC was proposing a "predictive guess". The actual FCC > rule is that a channel list is valid for 24hours, but if a device cannot > contact a database at that time it has permission to keep using the > channel list for a further 24hours (48hours total) I don't think this is a > good idea as it precludes a broadcaster reserving channels inside that > window, and, as mentioned above there is some discussion about making the > window much shorter to accommodate situations where broadcasters cannot > plan 24, or worst case 48 hours, in advance. Personally I prefer that the > device get a channel list that is good for some period, without any ifs > buts or maybes, and then it has to query again. This is much simpler than > trying to map matrices of start/stop times for various channels (maybe > with variable power limits) over an extended period. > Peter S. > > On MonAug/20/12 Mon Aug 20, 11:15 AM, "Benjamin A. Rolfe" > <[email protected]> wrote: > >> Thanks for the clarification. >> There are also two notions of what "schedule" means, at least in the FCC >> rules. There is the notion that the current channel availability data >> has a expiration time, and thus there is a time in the future when >> updating will be necessary. This is at most a day. Based on FCC rules, >> this could be a local time determined by the device using the channel >> data, and if that device is acting as a source for dependent device >> "using" includes providing it to other dependent devices (and it would >> have to provide the "valid until" time). I can imagine that other >> regulatory bodies (and perhaps the FCC in the future) will require that >> channel availability data provided by the data base also be tagged with >> the "valid until" information. This does not require a start time, as >> "now" is implied. >> >> The other notion of schedule time is that the database contains a >> predictive guess as to what channels will be available for the next 48 >> hours into the future. This is required by FCC (though the device must >> still check at least once a day if what it is using is still valid). A >> start/stop pair is required for this. >> >> I think either format can be used to represent time in both cases. It is >> also possible that the 48-hour schedule is all that PAWS needs to >> provide to meet the regulations and the "valid until" can be derived > >from that by the using device. >> Hope that helps. >> -Ben >> >>> Uh, the difference is representation of start/stop times. We both >>> propose >>> to send start/stop times. Vincent proposes that the representation of >>> time be a long integer seconds since an epoch. He would send two such >>> long integers. I propose it be an ISO 8601 time string. Specifically, >>> I >>> would propose an ISO 8601 interval limited to start/end, e.g. >>> 2011-03-01T13:00:00Z/2012-05-11T15:30:00Z. >>> >>> On 8/16/12 6:45 PM, "[email protected]" <[email protected]> >>> wrote: >>> >>>> It seems we have an agreement on the requirement to identify the >>>> spectrum, by using the start/stop frequencies, with optional channel >>>> identifiers. >>>> >>>> Wrt to the schedule, we have so far two proposals, one from Brian >>>> proposing the use of start/stop times for each spectrum unit available, >>>> and one from Vincent proposing to use of Unix Epoch time in seconds. We >>>> need to decide on this, so please send your preference on this topic to >>>> the list. >>>> >>>> - Gabor >>>> >>>> -----Original Message----- >>>> From: [email protected] [mailto:[email protected]] On Behalf Of >>>> Probasco Scott (Nokia-CIC/Dallas) >>>> Sent: Monday, August 13, 2012 10:12 AM >>>> To: [email protected] >>>> Subject: Re: [paws] use cases and requirements document >>>> >>>> Hi All, >>>> >>>> Given that we have completed two Working Group Last Call cycles and >>>> this >>>> next version will go to the IESG, I hope we could agree on minimal >>>> changes to the document, i.e. changes only to D.7 for this topic. This >>>> will ensure the proper requirements are established for the developing >>>> PAWS protocol. >>>> I believe Brian's proposed text captures the essential requirements. >>>> >>>> Kind Regards, >>>> Scott >>>> >>>> >>>> On 8/13/12 8:24 AM, "ext Rosen, Brian" <[email protected]> wrote: >>>> >>>>> <as individual> >>>>> I would prefer to not use the word "channel" in our documents at all >>>>> except for the term "channel identifier". I proposed "spectrum unit", >>>>> although any other term will do. "Channel" has too much baggage, A >>>>> simple editorial change like this is simple, and it's much better to >>>>> do >>>>> it now. >>>>> >>>>> I think we need power in both the query and the response. In some >>>>> domains, it may be that you specify what power you want to use and the >>>>> DB tells you what spectrum you can use at that power. In other, a >>>>> US-like rule may be in place. Also in either the query or the >>>>> registration, we need a device type, which should be an entry from an >>>>> IANA registry. This is how you get the US "Mode II" information. >>>>> >>>>> With regard to schedule, I would like to see two mechanisms >>>>> 1) a time by which the database should be queried again (which could >>>>> represent the next change in schedule) >>>>> 2) start/stop times for each spectrum unit available >>>>> >>>>> Both these should be optional in the response. >>>>> >>>>> My text >>>>> >>>>> The data model must support specifying spectrum availability. >>>>> Spectrum >>>>> units are specified by low and high frequencies and may have an >>>>> optional channel identifier. >>>>> >>>>> The data model must support a schedule for spectrum unit availability. >>>>> Two mechanisms must be supported. The response to spectrum >>>>> availability query may include a time by which the database must be >>>>> requeried. Each spectrum unit mentioned in the response may be >>>>> annotated with start and stop time/date. >>>>> >>>>> >>>>> >>>>> -----Original Message----- >>>>> From: Eric Chu [mailto:[email protected]] >>>>> Sent: Saturday, August 11, 2012 11:43 AM Eastern Standard Time >>>>> To: Teco Boot >>>>> Cc: Rosen, Brian; [email protected] >>>>> Subject: Re: [paws] use cases and requirements document >>>>> >>>>> >>>>> Hi everyone, >>>>> >>>>> Gathering all the shared points from everyone... I believe below is >>>>> the >>>>> complete list so far: >>>>> >>>>> >>>>> >>>>> * What's the best consistent representation of the words "channel >>>>> numbers" for non-TV spectrum >>>>> * Should we update the entire doc on the topic of ³channel² or >>>>> ³channel numbers² >>>>> * What¹s the best way to reduce vagueness in whether/how to include >>>>> "channel numbers" >>>>> * Is the reference to variable power required >>>>> * What does channel availability schedule mean >>>>> >>>>> >>>>> Brian's suggestion of replacing every instance of "channel" is >>>>> technically correctly. However, it is important for us to focus moving >>>>> forward. I would suggest we only work on the normative part of the >>>>> spec. >>>>> The section Gabor is proposing for us to modify... >>>>> >>>>> On what's the best generic label for the words "channel numbers", >>>>> channel identifier might be the most accurate and neutral "label". >>>>> Thoughts? >>>>> >>>>> On the question whether variable power is required, based on FCC >>>>> adjacent-channel rules, the database may limit the Mode II devices to >>>>> 100mW for some channels and 40mW for others. Therefore, the data model >>>>> needs to support specification of maximum power levels. >>>>> >>>>> Lastly, with regards to "schedule", the intent is to have a way of >>>>> informing devices when to operate for each frequency range. As long as >>>>> the data model supports, for example, a list of time ranges, it does >>>>> not prevent an implementation from providing a list with 1 entry which >>>>> corresponds to the "shortest available". The word "schedule" should >>>>> be >>>>> sufficient to capture this intent? >>>>> >>>>> We would like to propose the following text to address these points: >>>>> >>>>> "The Data Model MUST support specifying available spectrum. The Data >>>>> Model MUST support specification of this information by start and stop >>>>> frequencies and MAY also support specification of this information by >>>>> channel identifiers. The Data Model MUST support a >>>>> spectrum-availability schedule and maximum power levels for each >>>>> frequency range." >>>>> >>>>> >>>>> Thoughts? >>>>> Eric >>>>> >>>>> >>>>> >>>>> On 8/10/12 5:48 AM, Teco Boot wrote: >>>>> >>>>> >>>>> What about this: >>>>> >>>>> ³The Data Model MUST support specifying a list of available >>>>> channels. The Data Model MUST support specification of this >>>>> information >>>>> by start and stop frequencies, or equivalents such as center >>>>> frequencies with channel width or channel numbers with channel nummer >>>>> allocation scheme . The Data Model MUST support a channel availability >>>>> schedule and maximum power level for each channel in the list.² >>>>> >>>>> More thoughts on channel numbers: we likely run into problems in >>>>> bands without a channel numbering scheme, or for example sub channels >>>>> in TV bands. >>>>> >>>>> Teco >>>>> >>>>> >>>>> Op 10 aug. 2012, om 13:57 heeft Rosen, Brian het volgende >>>>> geschreven: >>>>> >>>>> >>>>> <as individual> >>>>> While I don't care if it's center and width or upper/lower, I >>>>> do think we will define the format in the protocol for >>>>> interoperability >>>>> reasons, but don't need to do that in requirements. It wouldn't hurt >>>>> to decide now and use consistent terms, but we don't need to. >>>>> >>>>> I think "band" won't work, as it usually implies a much wider >>>>> piece of spectrum that has a common purpose. The TV Band is all the >>>>> channels. >>>>> >>>>> >>>>> On Aug 10, 2012, at 2:37 AM, Teco Boot <[email protected]> wrote: >>>>> >>>>> >>>>> (somewhat late response) >>>>> >>>>> A center frequency and channel width is functional >>>>> equivalent to start/stop frequencies. So is channel number, with ref >>>>> to >>>>> channel number assignment scheme. For a requirements document, we just >>>>> need to specify what is needed. How it is encoded (Hz, wave length, >>>>> channel ID) is solution space. >>>>> >>>>> Seen our goal to make PAWS somewhat universal (not limited >>>>> to US TVWS), I do not prefer using channel numbers. >>>>> >>>>> Teco >>>>> >>>>> >>>>> Op 9 aug. 2012, om 21:55 heeft <[email protected]> >>>>> <[email protected]> het volgende geschreven: >>>>> >>>>> >>>>> Folks, >>>>> >>>>> During the last F2F meeting, there was an agreement to >>>>> make a slight update to requirement D.7 in >>>>> >>>>> http://www.ietf.org/id/draft-ietf-paws-problem-stmt-usecases-rqmts-06.t >>>>> xt, to make channel numbers optional to be supported. Ie, change the >>>>> current >>>>> D.7 >>>>> ³The Data Model MUST support specifying a list of >>>>> available channels. The Data Model MUST support specification of this >>>>> information by channel numbers and by start and stop frequencies. The >>>>> Data Model MUST support a channel availability schedule and maximum >>>>> power level for each channel in the list.² >>>>> to >>>>> ³The Data Model MUST support specifying a list of >>>>> available channels. The Data Model MUST support specification of this >>>>> information by start and stop frequencies and MAY include channel >>>>> numbers. The Data Model MUST support a channel availability schedule >>>>> and maximum power level for each channel in the list.² >>>>> >>>>> I¹d like to confirm this change on the list. If anyone >>>>> has any objections, let me know. Otherwise I¹ll plan to send the >>>>> document to the iesg after this change is implemented. >>>>> >>>>> - Gabor >>>>> _______________________________________________ >>>>> paws mailing list >>>>> [email protected] >>>>> https://www.ietf.org/mailman/listinfo/paws >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> paws mailing list >>>>> [email protected] >>>>> https://www.ietf.org/mailman/listinfo/paws >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> paws mailing list >>>>> [email protected] >>>>> https://www.ietf.org/mailman/listinfo/paws >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> paws mailing list >>>>> [email protected] >>>>> https://www.ietf.org/mailman/listinfo/paws >>>> _______________________________________________ >>>> paws mailing list >>>> [email protected] >>>> https://www.ietf.org/mailman/listinfo/paws >>>> _______________________________________________ >>>> paws mailing list >>>> [email protected] >>>> https://www.ietf.org/mailman/listinfo/paws >>> _______________________________________________ >>> paws mailing list >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/paws >> _______________________________________________ >> paws mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/paws _______________________________________________ paws mailing list [email protected] https://www.ietf.org/mailman/listinfo/paws
