Fw: stds-802-16-mobile: Sleep window parameters in Table 275a[From: Phillip Barber]
Title: Fw: stds-802-16-mobile: Sleep window parameters in
Tab
Sent: Sunday, November 02, 2003 4:52 PM
Subject: Re: stds-802-16-mobile: Sleep window parameters
in Table 275a
I understand, and think I
partially agree. I think the amount of absolute time spent in a
given sleep interval window is more important than percentage of time
that 4,096 frames represents. Absolute time affects
recovery-to-active operation to meet sleep interval QoS
request for session initiation. Percentage of time spent
sleeping versus listening affects power conservation, but is
essentially arbitrary, and has no QoS implications. So you want
the sleep interval/listening interval ratio to be something like
10-to-1. As long as the ratio is adequately high, you don't
really care about 10-to-1 or 12-to-1. But you certainly care
about 8 second absence versus 2 second absence. At
4,096 frames with 2ms frame sizes, the MSS would be spending eight
second time slices in sleep windows before entering a listening
interval--really too long to recover for QoS request for session
initiation while MSS was sleeping. Two second delay is
probably more reasonable, so a Max_Sleep_Interval window of 1,024
frames is more reasonable for the current model.
For my contribution C80216e-03_57
revised sleep mechanism, I should probably reduce final sleep window
bit size to 10 bits (1,024 frames) and expand sleep window iterations
to 10 bits (1,024 iterations). So using max values, no
single sleep window would exceed 2 seconds and the total time
through all sleep window iterations would be 87 minutes
before MSS would have to return to Normal Operation with Serving BS
(if you max out all variables). A pretty reasonable number.
Forcing the MSS to return to Normal Operation every hour- to two-hours
or so is a good idea because it allows the Serving BS to re-establish
that the MSS is still 'connected'. The MSS could have
dropped-off in the interim and the Serving BS would have no way to
know. Need to let Serving BS clean-up resources and allocations
periodically. Especially important in mobile systems.
Using normal sleep interval expiration to force the MSS to return to
Normal Operation is a more elegant mechanism than forcing the Serving
BS to send false traffic messages periodically to make the MSS exit
sleep and return to Normal Operation to find dropped MSS.
Itzik's response points to a one
second max and references previous literature. But I am not
aware of any critical QoS documents that indicate one second is an
imporant max recovery period to overcome QoS session initiation lag.
Indeed, for most common forms of multimedia traffic, of all types and
through all transmission mediums employed today, four to twelve second
session initiation windows are the rule. Also, on average, a two
second max window will result in a one second imposed average
latency. I just think two seconds is a better number to use than
one second for max period. But I will submit to the will of the
group.
Thanks for continuing to look at
this. I think it still could use more noodling.
Thanks,
Phillip Barber
----- Original Message -----
From: Ofer
Kelman
To: Phillip Barber ; stds-802-16-mobile@ieee.org
Sent: Sunday, November 02, 2003 7:45
AM
Subject: RE: stds-802-16-mobile: Sleep window
parameters in Table 275a
Phillip and
all,
I agree that
the 5 frames duration may me too small of a period, but at the same
time 4096 is much too much. To my
understanding, the sleeping interval should be around
10 times of the listening time. This gives us some 90% power
savings in time. to get better percentage the sleep interval
grows too much. For example take a ratio of 20 frames sleep and 2
frames listening time. It is around 89% power saving (taking into
consideration that the "wake-up" process consumes more
power then continues operation). While 30 frames of sleep with 2
listening frames goes to 96%. This shows that the additional 7% of
saving costs 30% in sleeping time.
I would
recommend 30 to be the maximum value.
Ofer
-----Original Message-----
From: Phillip Barber
[mailto:pbarber@broadbandmobiletech.com]
Sent: 28 October, 2003 6:16 PM
To: stds-802-16-mobile@ieee.org
Subject: stds-802-16-mobile: Sleep window parameters in Table
275a
Itzik and
all,
I have been working on a
revision to Table 275a. A few observations:
SS/Max_Sleep_Interval/Max.
Value seems very low. Shouldn't this be something more like
4,096 frames or more?
For
SS/Listening_Interval/Min. Value, didn't we settle on 4 frames at
Session 27?
Thanks
all.
Table 275a-Parameters and
Constants
System
Name
Time
Reference
Min.
Value
Default
Value
Max.
Value
SS
Min_Sleep_Interval
Minimum sleeping time allowed to
SS
2 Frames
SS
Max_Sleep_Interval
Maximum sleeping time allowed to
SS
5 Frames
SS
Listening_Interval
The time duration during which the SS,
after waking up and synchronizing with the DL transmissions, can
demodulate downlink transmissions and decides whether to stay awake or
go back to sleep
BS
BEA-ADV interval
Nominal time between transmission of
BEA-ADV messages
30s
BS
ASC-AGING-TIMER
Nominal time for aging of MSS
associations
100ms
BS
Neighbor_Info interval
Nominal time between transmission of
Neighbor_Info messages
600s
BS
Neighbor-Aging-Timer
Nominal time for aging of BS neighbor
association and removal from the dynamic Neighbor BS table
3600s
Thanks,
Phillip Barber