Hi Pat,
Thanks a lot for the insightful comments!
The main theme of my mail is to use transmit power control is to enable
better
spatial re-use of the channels, managed by an external controller. The
focus is
not much on the power savings. With respect to the effect of power
control on
CSMA behaviour for the shared timeslots, one comes across literature
that talks
about optimal power control that trades-off between hidden node and exposed
node problems. The latter is for better spatial re-use. As Michel
pointed out
in his mail, the nodes can use different output power levels. Left to them,
this could lead to unpredictable the contention regions, and all the
associated
unfairness issues as well.
A well provisioned power levels managed by a centralized controller can also
help support more "deterministic" tracks that use dedicated TX
timeslots. For
reasons I cited in my earlier mail, don't you think a handle to transmit
power
control helps in managing the network better, at least in the case of
non-CSMA
timeslots ?
Anand
On Monday 08 June 2015 10:49 PM, Pat Kinney wrote:
Reducing transmit power may seem like a great idea but it creates havoc in many systems due to
the hidden node problem. A reduction in transmit power will often
degrade the effectiveness of the CSMA mechanism which is used in shared
timeslots. The reduced effectiveness frequently appears as lost
packets, requiring retransmissions, requiring more energy than that
saved by reduction of transmit power. However, since the CSMA is not
required for TX only timeslots, changing TX power in these timeslots may
be done with fewer ill effects.
>
> Pat
> Pat Kinney
> Kinney Consulting LLC
> IEEE 802.15 WG vice chair, TG chair
> ISA100.11a WG chair
> O: +1.847.960.3715
> pat.kin...@kinneyconsultingllc.com
>
>
>
>
>
>
> On 8, Jun2015, at 10:33, Michel Veillette
<michel.veille...@trilliantinc.com> wrote:
>
> Hi Anand and Qin
>
>
>
> Ill like to introduce the idea of supporting the option of
adding the phyTXPower value in an IE within BEACON frames.
>
> Provisioning the phyTXPower can be an issue when targeting multiple
markets with different output power limits.
>
> Including the phyTXPower within BEACON frames will enable joining
nodes to adjust dynamically their output power based on a value managed
at the PAN coordinator.
>
>
>
> <image001.jpg>
>
>
> Michel Veillette
> System Architecture Director
>
> Trilliant Inc.
> Tel: 450-375-0556 ext. 237
> michel.veille...@trilliantinc.com
>
> www.trilliantinc.com
>
>
>
>
>
> From: 6tisch [mailto:6tisch-boun...@ietf.org] On Behalf Of Qin Wang
> Sent: 8 juin 2015 11:08
> To: an...@ece.iisc.ernet.in; Kris Pister
> Cc: 6tisch@ietf.org
> Subject: Re: [6tisch] 6top and transmit power control
>
>
>
> Hi Anand,
>
>
>
> Regarding to power management, there is a parameter in the
IEEE802.15.4 PIB, i.e. phyTXPower. You can control the transmitting
power by changing its value. Is that what you want? If so, I think
6tisch MIB will provide the interface to access phyTXPower, which will
be defined in the 6tisch-interface draft.
>
>
>
> Thanks
>
> Qin
>
>
>
>
>
>
>
> On Saturday, June 6, 2015 2:50 PM, "an...@ece.iisc.ernet.in"
<an...@ece.iisc.ernet.in> wrote:
>
>
>
> Hi Kris,
>
> Thanks!
>
> I was not sure if and how such a parameter can be accommodated in the
> current scheme of things, although it could be a useful control parameter
> from the operator's perspective.
>
> Anand
>
>
>
> > seems like a good idea.
> >
> > ksjp
> >
> > On 6/4/2015 4:15 AM, SVR Anand wrote:
> >> Dear All,
> >>
> >> A slight digression from the ongoing ML discussions. Hope the timing
> >> is OK!
> >>
> >> As we all know, transmit power control is one of the powerful knobs
> >> that can be
> >> used to minimize the interference and thereby improve the wireless
> >> network
> >> performance and also provide deterministic network. Cell breathing
> >> technique
> >> used in WLANs comes to our mind. When it comes to 6tisch, one might
> >> argue that
> >> with 16 channels at our disposal, the interference can be avoided
> >> through smart
> >> 6top cell management interface without worrying much about transmit
> >> power
> >> control. However, there can be scenarios where transmit power control
> >> might be
> >> required, for instance, (i) large scale dense deployments with heavy
> >> traffic
> >> demands (ii) Co-existing WiFi reducing available non-overlapping
> >> channels for
> >> 15.4 (iii) prevent wireless leaks beyond the periphery of the
> >> deployement
> >> region and (iv) OTF scheduling where nodes make local decisions for
> >> managing
> >> cells, may be more.
> >>
> >> One possibility is to leave the power management to the nodes. We are
> >> then
> >> leaving this to implementors to device their own algorithms to handle
> >> interference. Alternatively, a centralised controller (NME)
knowing the
> >> information about conflicting links can adaptively and optimally
> >> adjust the
> >> operating transmit power of the nodes to avoid the interference and
> >> maximize
> >> the wireless network performance.
> >>
> >> If we treat transmit power as one of the controllable parameters along
> >> with the
> >> cell management parameters, wondering if 6tisch 6top interface MIB is
> >> the place
> >> to define this. Or this parameter is beyond the scope of 6tisch.
> >>
> >> Any suggestions ?
> >>
> >> Anand
> >>
> >
> >
> > --
> > This message has been scanned for viruses and
> > dangerous content by MailScanner, and is
> > believed to be clean.
> >
>
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
> _______________________________________________
> 6tisch mailing list
> 6tisch@ietf.org
> https://www.ietf.org/mailman/listinfo/6tisch
>
> _______________________________________________
> 6tisch mailing list
> 6tisch@ietf.org
> https://www.ietf.org/mailman/listinfo/6tisch
>
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
> _______________________________________________
> 6tisch mailing list
> 6tisch@ietf.org
> https://www.ietf.org/mailman/listinfo/6tisch
--
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.
_______________________________________________
6tisch mailing list
6tisch@ietf.org
https://www.ietf.org/mailman/listinfo/6tisch
