RE: stds-802-16-mobile: Handoff and Sleep Mode Ad-hoc: Start of d iscussion
All,
For me it's OK also
Vladimir
-----Original Message-----
From: Changhoi Koo [mailto:chkoo@samsung.com]
Sent: Monday, June 09, 2003 7:47 AM
To: Itzik Kitroser; stds-802-16-mobile@ieee.org
Subject: Re: stds-802-16-mobile: Handoff and Sleep Mode Ad-hoc: Start of
discussion
Dear Itzik and all.
I fully agree with your suggestion and changes for the fast HO
Thanks
Changhoi Koo
----- Original Message -----
From: "Itzik Kitroser" <itzikk@runcom.co.il>
To: <stds-802-16-mobile@ieee.org>
Sent: Thursday, June 05, 2003 4:47 PM
Subject: RE: stds-802-16-mobile: Handoff and Sleep Mode Ad-hoc: Start of
discussion
> Dear Changhoi, Vladimir and All,
>
> Thank you for your perspectives.
> I think that an approach which will bridge between our views can be as
follows:
> 1. Have two backoff values (actually min and max for each case), one for
initial ranging and one for HO-initial ranging.
> 2. Make those values global, i.e. published in the UCD, this means, add to
current UCD encoding another two values:
> Ho_Ranging_Backoff_Start and Ho_Ranging_Backoff_End (with scope for all
PHYs).
> 3. No change for initial ranging backoff algorithm, add definition that HO
MSSs will perform truncated binary exponential backoff with [0..2^HO_BOFF]
value, when HO_BOFF in [Ho_Ranging_Backoff_Start,Ho_Ranging_Backoff_End].
>
> The motivation is as follows:
> a. I agree with Vladimir that the number of expected collisions will be
inherently low, therefore, there is no logic for exclusive windows to
eliminate collisions, the statistical spreading should do the work with
bounded guaranties.
> b. I also agree with Changhoi, that since we have two different processes,
with two different control and performance requirements, having two
different window parameters makes sense (even when the windows are
overlapping).
> c. I agree that from BS point of view, changing the windows boundary is
totally implementation dependent issue, from the MSS point of view, an
deterministic algorithm must be defined (i.e. item 3 above), otherwise, the
contention process will not work.
>
> Please provide feedback, and agree or disagree observations. I would like
for continue for the next topic.
>
> Regards,
> Itzik.
>
> > -----Original Message-----
> > From: Changhoi Koo [mailto:chkoo@samsung.com]
> > Sent: Thursday, June 05, 2003 04:14
> > To: Vladimir Yanover; 'Itzik Kitroser'; stds-802-16-mobile@ieee.org
> > Subject: Re: stds-802-16-mobile: Handoff and Sleep Mode Ad-hoc: Start of
> > discussion
> >
> >
> > Hello All
> >
> > Thanks fot your comments on Samsung's contribution.
> > Please let me make some answers
> > For Chairman's view, the boundary of backoff region would depend
> > on the number of entry call and HO call and it can be dynamically
> > allocated by the BS through the DL message which includes
> > information to be used to indicate boundary.
> > And your suggestion looks good and can be alternative in terms of
> > allocation and indication of backoff field. Furthermore, it seems
> > depend on the operation view.e.g how to handle and allocate the
> > boundary would be implementational issues.
> > However, most important thing would be that the different backoff
> > region should be defined and allocated for each entry call and HO
> > call. So I believe if we make a room for different backoff field
> > allocation on the messgae, everything will be O.K and there will
> > be no any problem.
> >
> > For Mr Yanover's view
> > Thanks for your comments. Unfortunately, we did not meet in the
> > last meeting so I had not chance to hear your valuable comments.
> > But I'm very happy to see mail from you...
> > You are right. Everything depends on the number of HO call and
> > entry call, and statistical charcteristics of the MSS. We may or
> > may not show some statistical references or simulation results.
> > Even we have a simple simulation results chich can be give the
> > evidence to be shown the useful approach of this proposal, But
> > I'm not sure whether the simulation results can be satisfied for
> > you. However, it is hard to evaluate and analysize the enough and
> > reasonable simulation resulta due to so many variables such as
> > MSS characteristics, call characteristics, number of MSS during
> > HO and any other parameters which can be obtained from
> > measurement under real fields..
> > I believe that the basic purpose of the backoff field would give
> > avoidance of the collision between the calls and the different
> > access delay can be happend according to the backoff field.And
> > the allocation scheme and direction can be treatable and
> > dynamically handled based on the cell load including entry call
> > and HOcall. If the BS does not want to allocate different backoff
> > field, it can do that..However, we don't need to such approache
> > and should allow the way for the performance enhancement.
> > Furthermore, Because it does not require the major changes and
> > H/W changes, and it can be done simply on the message level, We'd
> > better give minimum directions and way to assist the fast HO in
> > IEEE802.16e specificatin.
> > Thanks and Welcome further comments and discussions.
> > Changhoi Koo
> >
> >
> > ----- Original Message -----
> > From: "Vladimir Yanover" <vladimir.yanover@alvarion.com>
> > To: "'Itzik Kitroser'" <itzikk@runcom.co.il>;
> > <stds-802-16-mobile@ieee.org>
> > Sent: Thursday, June 05, 2003 12:52 AM
> > Subject: RE: stds-802-16-mobile: Handoff and Sleep Mode Ad-hoc:
> > Start of discussion
> >
> >
> > > Hello All,
> > > This is about C802.16e/03-28 document. The tool suggested
> > > for the solution of the problem seems appropriate: allocate for
> > mobile users
> > >
> > > a separated initial ranging channel. But it would be more convincing
> > > with some statistical data. Is the problem really hard? The
> > answer depends
> > > on traffic/mobility characteristics.
> > >
> > > For example, we know that for voice cellular networks busy hours
arrival
> > > rate may reach 3-4 users/sec per cell. If we assume that data
> > terminals are
> > > not more mobile than cellular
> > > phones then we may expect same order of maximum arrival rate for
802.16e
> > > cells.
> > > If we take MAC frame duration = 5 ms then we have 50-60 frames
> > per SS for
> > > initial ranging. So we may allocate MAINT region with 1-2 slots
> > once per 5
> > > frames
> > > and configure backoff window to 2 or 4 slots and still have 4-5
> > attempts for
> > >
> > > power adjustment of each incoming SS.
> > >
> > > Now, what is the role of "fixed" users in this picture?
> > Probably, busy hours
> > > are those when people power up their SSs in the evening. If 100
> > such events
> > > are
> > > distributed over one hour interval, then we have 36 sec for
> > each user, 10
> > > times more than for mobile one. Thus, under given assumptions, there
is
> > > just a small interference from fixed SSs. Do we need a separated MAINT
> > > channel
> > > in this case?
> > >
> > > It would be interesting to hear from other participants of the
> > discussion
> > > on their view on traffic/mobility characteristics of future
> > 802.16e users
> > >
> > > Vladimir
> > >
> > > -----Original Message-----
> > > From: Itzik Kitroser [mailto:itzikk@runcom.co.il]
> > > Sent: Monday, June 02, 2003 6:53 PM
> > > To: stds-802-16-mobile@ieee.org
> > > Subject: stds-802-16-mobile: Handoff and Sleep Mode Ad-hoc: Start of
> > > discussion
> > >
> > >
> > > Hello All,
> > >
> > > Given enough time passed, I would like to start the discussion
> > in the scope
> > > of this group.
> > > As indicated in working document the following topics should be
> > discussed:
> > > ---->
> > > 1. Contributions to discuss:
> > > a.C802.16e/03-28: Fast handoff service
> > > b.C802.16e/03-30r1: Reporting of scanning results
> > > c.C802.16e/03-31: Sleep mode enhancement
> > > 2. Clarification on the types of handoff that are supported;
> > currently the
> > > text implies that two kind of handoff are supported
> > (break-before-make and
> > > make-before-break) but descriptions are provided only for the
> > > break-before-make type. I would like to request proposals on
> > > make-before-break type (relevant to the current Tga/d
> > technology of course)
> > > 3. Provide message flow diagrams for the Sleep mode and Handoff
> > procedure,
> > > such diagrams must provide a clear explanation of the actions
> > performed by
> > > the BS and by the MSS. The diagrams must be considered for
> > different kind of
> > > scenarios (i.e. handoff success, target BS rejection etc.)
> > > <----
> > >
> > > I would like to open the discussion with item 1.a. "C802.16e/03-28:
Fast
> > > handoff service " contribution:
> > > This contribution presents the idea of improving the Initial
> > Ranging of MSS
> > > during handoff by using two backoff types of backoff parameters:
> > > 1. "Regular" backoff (min) value for initial ranging, called
"MAX_BOFF"
> > > 2. HO MSS backoff (min) value for MSS during handoff time,
> > called "HO_BOFF"
> > > The backoff window of MSS doing HO will be: [0,2^HO_BOFF] and
> > the backoff
> > > window for MSS doing regular (i.e. not handoff) network entry will be:
> > > [2^HO_BOFF+1,2^MAX_BOFF].
> > >
> > > The advantage of this method, is that, when using a shared contention
> > > resource, the MSS performing HO will not collide with MSS
> > performing initial
> > > network entry.
> > > The drawback of this method is the inherited delay for the
> > initial network
> > > entry process for regular MSSs.
> > >
> > > My view on this issue is:
> > > a. One of the main targets of the 802.16 handoff procedures is
> > to make the
> > > handoff process efficient and fast. Coming for this
> > orientation, we have the
> > > ability to make the initial network synchronization for MSS performing
> > > handoff, a contentionless process. This is achieved by using the
> > > "Fast_UL_ranging_IE", which is sent unsolicited, by the target
> > BS to the MSS
> > > coming in. If the aspire that most of the MSS will be able to
> > do so, than
> > > the problem solved by C802.16e/03-28 dose not exists.
> > > b. If there are subscribers, which still required to perform
contention
> > > entry to the target BS, then due to the fact that the number of MSS
that
> > > performing an initial ranging in a stabilized system is very
> > low, it seems
> > > more reasonable to make two contention windows, which are overlapping:
> > > b1. "Regular" backoff (min) value for initial ranging, called
> > "MAX_BOFF",
> > > backoff window [0,2^MAX_BOFF]
> > > b2. HO MSS backoff (min) value for MSS during handoff time, called
> > > "HO_BOFF", [0,2^HO_BOFF]
> > > When MAX_BOFF is large enough, then the probability of
> > collision is still
> > > low.
> > >
> > > Please provide your views on this issue, deadline is 04/06/03.
> > >
> > > Best Regards,
> > > Itzik.
> > >
> > >
> > >
> > >
> > >
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> > >
> > >
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Dr. Vladimir Yanover
Alvarion Ltd.
21 A Habarzel St. Ramat - Hahayal Tel - Aviv 69710
P.O. Box 13139, Tel-Aviv 61131, Israel
Tel.: +972-36457834
Fax: +972-36456290
E-Mail: vladimir.yanover@alvarion.com
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