Re: [coman] Merged terminology draft

[peter van der Stok <[e-mail]>]

Hi Carsten,

thanks for the pointer.
I did not want to go into in watss and watthours but wanted to classify 
according to network behavior.
I thought that was more relevant in the long term because technology 
advances on battery side, harvesting side, and transmitter side.
However, at the end of the day these devices are optimized to a wanted 
behavior on the network for a minimum cost.

Peter

Carsten Bormann schreef op 2012-11-09 16:17:
> Hi Peter,
>
> in RFC6606, we are using the following terms (section 5):
>
>    o  host nodes drawing their power from primary batteries or using
>       energy harvesting (sometimes called "power-constrained nodes")
>
>    o  mains-powered host nodes (an example of what we call "power-
>       affluent nodes")
>
>    o  power-affluent (but not necessarily mains-powered) high-
>       performance gateway(s)
>
>    ... (further distinctions not relevant here)
>
> Clearly, it is a bit more complicated than just power-constrained vs.
> power-affluent.
>
> Even for power-affluent nodes, we don't want to waste energy (green
> and all that).
> One group of power-affluent nodes has a tens-of-kJ secondary battery
> that is regularly recharged (e.g., smartphones), so the energy supply
> is large, but with a defined limit per period (e.g, 24 hours for most
> smartphones); a typical amount of power continuously available (on
> average) is in the hundreds of mW.
>
> The typical primary-battery powered node has an average power
> availability on the order of tens to hundreds of µW.  So there is a
> clear difference -- around three orders of magnitude.  That should
> nicely separate the classes.
>
> Energy harvesting nodes are different enough to warrant their own
> group.  But there is a group of energy harvesting devices that find
> enough energy to almost be power-affluent.  So it might be useful to
> actually give an approximate boundary, e.g., in µW actually available
> averaged over a long time.  (That doesn't work very well for
> event-based harvesting, but you can just assume an event frequency 
> and
> likely will arrive at a useful number.)
>
> Grüße, Carsten
>
>
> On Nov 9, 2012, at 09:51, peter van der Stok <[e-mail]> 
> wrote:
>
>> Dear all,
>>
>> Next to the classification on memory, I should like to add a 
>> classification on power availability. In small nodes the largest power 
>> consumer is the transmitter. So I propose to classify the nodes 
>> according to their power-supply expressed as its transmission 
>> capacity. I propose three types of devices:
>>
>> P0: battery-less devices. They have a capacitor which is charged by 
>> harvesting power delivered by a small movement or light. The stored 
>> energy  is just sufficient to send 1 or at most 2 packets per 
>> communication. For example, think of a light switch where the 
>> transmission power is delivered by pushing the button.
>>
>> P1: battery-constrained devices. They have a battery with a limited 
>> charge. The device can continue sending packets over years by 
>> executing a cycle of relatively long off periods and short on periods 
>> in which a few packets can be sent and received. For example, think of 
>> a battery-powered temperature sensor with a life-time of 7-10 years.
>>
>> P2: battery-unconstrained devices. They may have a battery which is 
>> usually rechargeable. The device can send and receive packets at any 
>> moment during its operational life. For example, think of a thermostat 
>> connected to an external power supply.
>>
>> Hope this is helpful.
>>
>> Peter van der Stok
>>
>>
>> Carsten Bormann schreef op 2012-11-08 20:43:
>>> As discussed in LWIG and COMAN today, Mehmet and I have extracted 
>>> our
>>> common, "essential" terminology out of the LWIG WG document and
>>> Mehmet's COMAN draft, and merged it into one document.
>>>
>>> The intention is to move this forward within LWIG independently, in 
>>> an
>>> expedited way, and reference it from the next version of
>>> draft-ietf-lwig-guidance as well as further COMAN documents.
>>>
>>> Since we got positive feedback in the LWIG meeting for this little
>>> piece of surgery, I'm now asking the LWIG chairs to ask the 
>>> question
>>> on the mailing list for working group adoption of this draft.
>>>
>>> Htmlized:        
>>> http://tools.ietf.org/html/draft-bormann-lwig-terms-00
>>>
>>> Clearly, this isn't perfect yet, but further improving the document 
>>> is
>>> the point of the WG process.
>>> Of course, comments that could lead to improvement are highly 
>>> welcome.
>>>
>>> Grüße, Carsten
>>>
>>> _______________________________________________
>>> coman mailing list
>>> [e-mail]
>>> https://www.ietf.org/mailman/listinfo/coman
>>
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