[6lowpan] IP over Narrowband Radios

["Timothy J. Salo" <[e-mail]>]

Hi,

Is anyone looking at running IP over narrowband very high frequency
(VHF) and ultra high frequency (UHF) data radios?  A couple of major
issues come to mind.

First, bandwidth is extremely limited and valuable.  These radios may
provide bandwidths of only 9,600 bits-per-second (bps), 4,800 bps, or
even less.  Networks composed of these radios might be viewed as
_wide-area_ wireless sensor networks (WSNs) (in contrast to the
"local-area" WSNs typically built with 6lowpan devices).  Link
distances in these narrowband networks may be kilometers or even
tens-of-kilometers long.  The narrowband radios used in these networks
may transmit with one to five watts of power.  In my view, the
extremely low bandwidths of these networks, combined with the very high
energy cost of transmitting a bit, is likely to drive different
engineering tradeoffs in protocol design (compared to 802.15.4
networks, where link bandwidths are relatively high and the cost of
transmitting a bit is relatively low).  For example, in a narrowband
network, it may make much more sense to compute or store information
whenever possible, rather than transmitting it (more than one) over
the air.  While I have not yet done the analysis, it seems to me that
it is quite likely that the engineering tradeoffs make in 6lowpan are
different than the engineering tradeoffs that might be made in a
narrowband radio network.  Perhaps, there is utility in a collection of
IP-over-narrowband-radio RFCs.

Second, there is a pretty complete lack of standards for narrowband
data radios, most importantly at the physical and MAC layers.  While
this topic is outside of the purview of the IETF, it is a serious
impediment to building interoperable products.  It might also complicate
the process of standardizing IP-over-narrowband-radio specifications.

-tjs