[Tinyos-devel] Feedback on TEP 124

[Omprakash Gnawali]

Thanks Martin for your comments. I think we are down to one final item
in our discussion.

...
> Section 2.3:
>
>>> One popular way to define the
>>> bi-directional link quality between a node pair (A,B) as the
>>> probability that a packet transmitted by A will be successfully
>>> received and acknowledged by B.
>
> Rewrite: Either insert "is" after "way" or replace "as" by "is" or
> something.
>
>>> This approach computes the
>>> bi-directional link quality of a node pair (A,B) as the product of the
>>> link quality of (A,B) and (B,A).
>
> Suggest to rewrite as: "According to this definition, the link quality is
> computed as ..."
> However, the step from the definition of link quality as the "roundtrip"
> success
> probability to the product of the link qualities is not correct.
> As I said earlier, this would only hold if the successes of the two
> transmissions were independent, and in most cases they are not. So the
> product
> is a pessimistic metric, and I'd prefer to use the minimum of the two
> probabilities.
> At least a remark should be included that taking the product is only valid
> assuming
> independence (and does not follow directly from the definition above); and
> perhaps a scenario can be included where independence would be justified
> (I can't think if any except some far-fetched ones such as high mobility).

I have shortened the text:
"
One popular way to define the
bi-directional link quality between a node pair (A,B) as the
probability that a packet transmitted by A will be successfully
received and acknowledged by B. This approach computes the
bi-directional link quality of a node pair (A,B) as the product of the
link quality of (A,B) and (B,A).
"

to

"Routing protocols often
compute the bi-directional link quality of a node pair (A,B) as a
function (product, min, etc.) of the link quality of (A,B) and (B,A).
"

so that we limit ourselves to observations on how routing protocols
use the information that is exchanged using this protocol. What do you
think?

- om_p