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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
From: Phillip Barber
To: Ofer Kelman ; Itzik Kitroser ; stds-802-16-mobile@ieee.org
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