Hi,
I have addressed the first major comment to the Use Cases draft given
by several reviewers, which was about the typical characteristics of
LoWPANs being out of date. Here is a new list, I hope it better
reflects the current state of the art.
o Limited processing capability: the smallest common LoWPAN nodes
have 8-bit processors with clock rates around 10 MHz. However,
the most commonly used models have either 16-bit or 32-bit cores
(typically ARM7), running at frequencies in the order of tens of
MHz.
o Small memory capacity: common RAM sizes for LoWPAN devices consist
of a few kilobytes, usually 4K or 8K bytes, but reaching up to
256K bytes for high-performance models.
o Low power: wireless radios for LoWPANs are normally battery-
operated. Their RF transceivers often have a current draw of
about 10 to 30 mA, depending on the transmission power level. In
order to reach common indoor ranges of up to 30m and outdoor
ranges of 100m, the used transmission power is set around 0 to 3
dBm. Depending on the processor type, there is an additional
battery current consumption of the CPU itself, commonly in the
order of tens of milliamperes. However, the CPU power consumption
can often be reduced by a thousandfold by switching to sleep mode.
o Short range: the Personal Operating Space (POS) defined by IEEE
802.15.4 implies a range of 10 meters. For real implementations,
the range of LoWPAN radios is typically measured in tens of
meters, but can reach over 100 meters in line-of-sight situations.
o Low bit rate: the IEEE 802.15.4 standard defines a maximum over-
the-air rate of 250 kb/s, which is most commonly used in current
deployments. Alternatively, three lower data rates of 20 kb/s, 40
kb/s and 100 kb/s are defined.
Greetings,
Dominik
On Wed, Sep 30, 2009 at 1:20 PM, 6lowpan issue tracker
<[email protected]> wrote:
> #56: Update Characteristics
> -------------------------------------+--------------------------------------
> Reporter: [email protected] | Owner:
> Type: defect | Status: new
> Priority: major | Milestone:
> Component: usecases | Version:
> Severity: - | Keywords:
> -------------------------------------+--------------------------------------
> The list of typical characteristics of LoWPAN nodes must be updated.
>
> --
> Ticket URL: <http://trac.tools.ietf.org/wg/6lowpan/trac/ticket/56>
> 6lowpan <http://tools.ietf.org/6lowpan/>
>
>
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