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Hi
All,
I have the
following thoughts on HO process:
1. Since
we are considering the possibility of allowing SHO and fast BS
switching HO, we adopt an acitve set maintenance procedure regardless of the HO
type (BBM, MBB Hard HO, SHO or fast BS swiitching).
2. I propose to
change the current HO process defined in 16e to make it more deterministic. With
the current definition, the HO decision point could be at the BS or the MSS, and
any of the messages maybe or may not be sent during a HO. I think this allows
for too many possibilities, it's hard to implement and maintain a state machine
with so many undeterminstic events. When operating and optimizing a
larget network, it would be easier to have a more defined HO procedure. I
propose we do the following:
a) The HO decision
point should be at the BS. The MSS can assist in the HO process by reporting a
list of recommaned target BS, but the BS directs to the MSS to handover to a
specific active set (the list of serving BS).
b) There is a
minimum pair of messages have to be sent during a HO: BS Handover Command (or if
we don't want to add a new message, we can just use BS Handover Request to
direct the MSS) and MS Handover Indication. When the BS decides a HO should
take place and chooses the new active set, the BS should send BS Handover
Command to the MSS. When the MSS has performed the HO, the MSS should send
MS Handover Indication to indicate the status of the handover. The MSS can use
this message to Reject the HO if it has to.
c) For the MSS
assisted HO, the HO can be triggered by the MSS sending MS Handover Request.
However, this message doesn't have to result in HO. The BS should send BS
Handover Response just to stop possible retransmission of MS Handover Request
message. For BS triggered HO, the BS just need to send BS Handover Command to
start the HO process.
d) I believe no
matter what type of HO we are supporting, we should use the same HO process as
defined above with possiblity different parameters included in the message. i.e.
For a HO with Level 3 backbone communication, the BS Handover Command message
can indicate skipping certain steps when the MSS performing network entry at the
target BS (maybe just ranging necessary).
Just some of my
thought. Thanks.
Best
Regards,
Mary
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