[e2e] Opportunistic Scheduling.
detlef.bosau at web.de
Mon Jul 2 07:42:02 PDT 2007
Hi to all.
Some weeks ago, I asked some questions about this topic on the e2e-list.
Perhaps, the TCCC list might be more appropriate. However, I´m not
quite sure. So, if I´m completely wrong here, I would appreciate if
someone can please give me a hint.
I refer to systems like the Qualcomm 1xEV-DO wireless system, i.e. to
systems with a high data rate TDM downlink from a base station (BS) to
several (mobile) terminals (UE) and dedicated CDMA uplinks from the UE
To my understanding, at BS there is one queue per UE. All queues are
served in turn and the question is which scheduling mechanism is
Now, there is a huge amount of literature about this issue and perhaps I
cannot place all of my questions into this one post, but let me please
ask the following few.
1. In uplink direction, CDMA is used. To my understanding, the use of
CDMA requires a rather precise channel state model at least for the
purpose of propper power control. So the question is: Can I reasonably
assume a channel model on each terminal which particularly allows the
terminal to identify periods of "locally high SNR", i.e. periods of
constructive interference when Rayleigh fading is considered, and
periods of "locally low SNR", i.e. periods with destructive interference
To my understanding, each terminal issues a "data rate control" message
once in a time slot and the content of this message could be derived
from such a channel model.
Is this correct?
2. When I look at the "opportunistic scheduling" algorithm as used e.g.
by Jalali, Padovani and Pankaj, I honestly do not understand how the
rationale of Kelly´s "Charging and Rate Control for Elastic Traffic"
paper does apply to this algorithm.
Could someone please give me some hints on this one?
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