[e2e] Ressource Fairness or Througput Fairness, was Re: Opportunistic Scheduling.

Detlef Bosau detlef.bosau at web.de
Mon Jul 16 14:43:40 PDT 2007

For some reasons, a post of mine did not appear in the list.

So, I will only repeat the very essential parts:

I refer to the HSDPA downlink which is shared by some set of users. The 
shared ressource is hence the service time at BS. Let´s consider the 
users, not the flows. So each user gets a certain share of service time.

Although there is one common ressource, the individual users may 
experience different noise levels which affect the achieved throughput 
for a user.

Now the most basic question is:

Do we pursue ressource fairness?
Or do we pursue throughput fairness?

To my understanding of the End to End design, we typically pursue 
_ressource_ fairness, wheres the actual literature on HSDPA and the like 
pursues _throughput_ fairness.

Do you agree here?

In general, I see three concerns in this context, which I cut from this 
post´s draft, but I think they may be understood as well:

1.: In literature dealing with HSDPA and the like whe have a  mixup
between the terms service rate and code rate.
2.: PF scheduling pursues throughput fairness whereas in best effort
networks, we want to pursue ressource fairness instead.
3.: Kelly´s "recipe" on elastic traffic simply does not apply here.
Elastic traffic is not best effort traffic. Elastic traffic comes with a
utility function while best effort traffic does not. And because best
effort traffic is equally charged on a per ressource basis, I don´t see
Kelly´s work to be applicable here.

Do you agree here?


Detlef Bosau                          Mail:  detlef.bosau at web.de
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