Re: [manet] New drafts for DLEP layer1 metrics

[Abdussalam Baryun <[e-mail]>]

On Mon, Sep 13, 2021 at 9:12 AM Henning Rogge <[e-mail]> wrote:

> On Sun, Sep 12, 2021 at 11:19 PM Abdussalam Baryun
> <[e-mail]> wrote:
> >> I think the most work have to be done for the "BitError" TLV in the
> radio-quality draft... I am still not happy with the encoding but I am not
> quite sure what to do.
> >
> >
> > for the radi-quality-draft ....the error bit-rate not much value only if
> router knows the data rate/speed, which is specified in rfc8175, so I
> suggest  the draft needs to show the importance of this item related to
> data item of speed.
>
> If you look up some technical specification of a digital radio, you
> will (most likely) find tables for each modulation that show the
> correlation between biterror-rate and (necessary) signal-to-noise
> ratio. This means a radio measuring the biterror rate can give you an
> estimate what error-rate you can expect at other modulations.
>

There are some-assumptions (e.g low mobility environment) in all tables. As
usually assumes fixed data-speed and channel-bandwidth, so any increase in
data rate increases bit error rate depending on physical-comm-channel.


> The biterror rate will also make it possible to estimate the different
> frame-error-rates of small and large frames, which could give you a
> more precise way to calculate the link metric for a routing protocol.
>

That should be discussed I think in the draft. Is there a possibility of
error in getting the BER? however, the bit-error rate is not a rate of
time, just number of errors detected per received bits, also the modulated
signal is not in bits but demodulated is in bits. Each channel has a
maximum data rate, getting equal to that speed or less can increase or
reduce bit error rate while fixed modulation, channel, and noise.

For example, if the router finds increase/decrease in error rate without
knowing changes in data speed then it will expect either change in noise or
channel. Therefore, I suggested the knowledge of speed with BER and some
details on ways of estimating BER or frame-error-rate in draft.

Best Regards
AB