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Re: [rohc] [Fwd: I-DACTION:draft-svanbro-rohc-lower-layer-guidelines-00.txt]
Roberto,
The purpose of producing a draft in the ROHC wg with lower layer
guidelines is to push these kind of discussion and work to the
standardisation bodies were they belong. This allows us in ROHC to focus
on development of an efficient scheme. E.g., the discussion of how to
enable error detection in for example 3GPP type of links should thus be
solved in related groups in 3GPP. It is however important that we in
the ROHC wg makes sure that the scheme is possible to use in relevant
systems such as those standardized by 3GPP. However, I think that this
specific question is an issue for 3GPP rather then the ROHC wg.
To give an short answer:
RLC and PDCP are layer 2 protocols in 3GPP and they don't provide with
this kind of error detection. The error detection is instead done at the
physical layer - layer 1. If you look at the attributes of an UMTS
bearer (in 3GPP 23.107 for example) you'll se that there are parameters
for residual bit error rate, etc. It is possible to choose a certain
value for residual BER, which results in that a CRC of for example 8 or
16 bits is used for error detection. Moreover, in release 99 of 3GPP is
already now RFC2507 supported and 2507 requires also error detection on
headers.
Hence, I am confident that 3GPP type system can provide with the
required error detection but we must put requirements on this error
detection.
/ Krister
Roberto Winkler wrote:
>
> hello,
>
> I have a question about the section 3.1.1 'Error detection on (compressed)
> headers': at present, 3GPP specs on PDCP and RLC do not seem to match the
> requirement set by existing header compression schemes on layer 2 ability
> to detect errors and this is mostly true if Unacknowledged or Transparent
> RLC operation modes apply. How do you plan to solve this issue: by
> suggesting modifications to the current draft versions of these
> specifications or what else ?
>
> >Hi,
> >
> >A new Internet Draft is now available from the
> >on-line Internet-Drafts directories:
> >draft-svanbro-rohc-lower-layer-guidelines-00.txt
> >(see below)
> >
> >The draft elaborates on how to incooperate robust
> >header compression (ROHC) schemes into lower layers.
> >This draft corresponds to the "I-D of layer-2
> >design guidelines." as described in the ROHC charter.
> >
> >The draft will (most likely) be presented at the ROHC
> >meeting. Comments are welcome!
> >
> >Cheers,
> >
> >/ Krister Svanbro
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> >Subject: I-D ACTION:draft-svanbro-rohc-lower-layer-guidelines-00.txt
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> >A New Internet-Draft is available from the on-line Internet-Drafts
> >directories.
> >
> >
> > Title : Lower Layer Guidelines for Robust Header Compression
> > Author(s) : K. Svanbro
> > Filename : draft-svanbro-rohc-lower-layer-guidelines-00.txt
> > Pages : 7
> > Date : 13-Mar-00
> >
> >This document describes lower layer guidelines for robust header
> >compression (HC). The purpose of this document is to support the
> >incorporation of robust header compression algorithms, as specified
> >in the ROHC working group, into different systems such as those
> >specified by 3GPP, 3GPP2, ETSI, etc. This document treats general
> >guidelines as well as guidelines specific for cellular systems.
> >
> >A URL for this Internet-Draft is:
> >http://www.ietf.org/internet-drafts/draft-svanbro-rohc-lower-layer-guidelines-0
> >0.txt
> >
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> >
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>
> Roberto Winkler
> Senior Researcher
> Fondazione Ugo Bordoni
> Via B. Castiglione, 59
> 00142 Rome Italy
>
> tel +39 0654803411
> fax. +39 0654804404
> e-mail wnk@fub.it
>
> ---
> Mailing list for Robust Header Compression WG
> Archive: http://www.cdt.luth.se/rohc/
--
__________________________________________________________
Krister Svanbro, M.Sc. - Ericsson Research
AWARE - Advanced Wireless Algorithm Research at Erisoft
Box 920 | Tel. : +46 920-20 20 77
SE-971 28 Luleå | Fax : +46 920-20 20 99
Sweden | GSM : +46 70-621 69 42
mailto:Krister.Svanbro@epl.ericsson.se