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.