Re: [rohc] Liaison towards 3GPP

[Krister Svanbro <krister.svanbro@lu.erisoft.se>]

I have also seen these not yet concretized proposals for header
stripping and I don't think that they are a preferred way. They violate
the end-to-end integrity of IP. To me it seems like these proposals aim
at "eating the cake and still try to keep it".

Header stripping would be specialised per service standards that won't
be future proof. Furthermore, I seriously doubts that there is any large
gain in capacity having this kind of algorithms. The proposals I've seen
involves sending some header related information over the air-interface,
hence they will create some overhead. Since there are no actual detailed
proposals on header stripping (to my knowledge) it is not possible to
estimate the overhead, however, it is not unlike that it would be some
0.x of a byte overhead in average per packet.

Given the propsals for header compression in ROHC wg today, the
difference in efficiency will not be large. ROCCO for instance is
currently able to compress the header down to an average of appr. 1
byte. I don't expect the final scheme to be any less efficient. Hence,
with header compression the efficiency will be only slightly smaller,
but you have the very desirable property of IP end to end. 

Regards, 

/ Krister

 

"Casati, Alessio (Alessio)" wrote:
> 
> > Since bandwidth
> > is scarse in cellular system, standards for robust header compression
> > algorithms are essential to achieve spectrum efficiency.
> >
> I've seen some proposals for header stripping, that is
> deliver the RTP payload to the other end of the
> wireless channel where the headers are locally reconstructed.
> 
> It is true that the network side would have to terminate RTP and
> play out real time streams, thus potentially increasing complexity
> in the RNC.
> 
> On the other hand, one could argue that however
> efficient the Comression
> algorithm could be, stripping the header would
> save some octets on the average, and some $ billions
> - as per Carsten's estimate.
> 
> I think we need a ROHC algorithm anyway to run efficiently
> a host of apps, but I'm not sure
> that the header stripping proposals won't be the
> preferred way to deliver voice in wireless nets.
> 
> Any opinions?
> 
> alessio

-- 
 __________________________________________________________

 Krister Svanbro, M.Sc.  -  Ericsson Research 
 AWARE - Advanced Wireless Algorithm Research at Erisoft
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