> -----Original Message-----
> From: EXT Andrew Worsley [mailto:epaanwo@asac.ericsson.se]
> Sent: Tuesday, April 04, 2000 6:09 PM
> To: Phil Neumiller
> Cc: rohc@cdt.luth.se; pilc@lerc.nasa.gov
> Subject: [rohc] Re: [MOBILE-IP] Comments on PILC draft
>
......
> I assumed packets were segemented into segements of size f
> with with two
> bytes of overhead per segment (1 byte CRC and 1 byte count?),
> ignored the Nack traffic (as it's in the other direction?) and got
> for the average amount transmitted (in the one direction)
> for a packet of
> length D:
>
> T = ((D/f)+1)*(f + c)/p
>
> where f = segement size (I called it fragment)
> c = size of segement overhead
> p = probability of segment transmission, assuming a
> constant BER.
> i.e. p = 1 - (1 - BER)**(f+c)
Just want to point out a typo here. If p is the probability that
a segment is transmitted successfully, p should equal to
(1 - BER)**(f+c). The p above actually gives the probability of
a failed transmission.
Zhigang Liu
>
> and I assume the last segment is truncated to only
> contain the remaining
> data, if not you need an upper bound on the segment size
> say 50 bytes.
>
> For c = 2, D = 640
> Optimal values for f were:
>
> BER = .01 f = 4 p = 0.617290 efficiency = 2.430
> BER = .001 f = 16 p = 0.865825 efficiency = 1.299
> BER = 0.0001 f = 50 p = 0.959251 efficiency = 1.084
> BER = 1e-05 f = 150 p = 0.987914 efficiency = 1.026
>
> (efficiency is how much data is transmitted in the one direction
> divided by the size of the original data)
>
......
>
> Andrew Worsley
> ---
> Mailing list for Robust Header Compression WG
> Archive: http://www.cdt.luth.se/rohc/
>
This archive was generated by hypermail 2b29 : Mon Jan 28 2002 - 09:12:24 EST