[Tinyos-devel] 4bitle LinkEstimatorP.nc

[Omprakash Gnawali]

On Mon, Dec 1, 2008 at 3:45 AM, Andreas Köpke <koepke at tkn.tu-berlin.de> wrote:
> Hi, I'm wondering about the exponential weighted average implementation in the
> 4bitle:
>
>  void updateEETX(neighbor_table_entry_t *ne, uint16_t newEst) {
>    ne->eetx = (ALPHA * ne->eetx + (10 - ALPHA) * newEst)/10;
> }
> here, the influence of newEst is limited to newEst/10 -- underestimating the
> etx.
>
> I think it should round to nearest:
>
> void updateEETX(neighbor_table_entry_t *ne, uint16_t newEst) {
>    ne->eetx = (ALPHA * ne->eetx + (10 - ALPHA) * newEst + 5)/10;
> }

Adding 5 will cause the estimate to veer of the historical value
(eetx) or the new measured value (newEst). In your experience, adding
5 helped?

If newEst is a high value enough times this function is called, eetx
will approach newEst.

- om_p