Supporting Femtocell: on Interference Mitigation for Unconnected Mobile Station
Document Number: IEEE C80216m-09_1967r1
Date Submitted: 2009-09-22
Source:
Ying Li, Baowei Ji, Zhouyue Pi,
Jung Je Son, Anshuman Nigam,
Youngkyu Baek
Email: yli2@sta.samsung.com
Phone: +1-972-761-7903
Samsung Electronics
Nader Zein, Linghang Fan
NEC
nader.zein@eu.nec.com
Venue:
IEEE Session #63
Base Contributions:
Re:
Contribution in support of a comment on LB30
Purpose:
Notice:
Discussion and Approval
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Problem definition
• Large interference from an inaccessible Femtocell
may saturate or block the MS radio receiver, such
that it will not able to maintain the
communication with the serving BS.
• When a non-member AMS is seriously interfered
by a neighbor CSG-closed Femtocell ABS and
cannot get any service from the network, what
should be done for such MS?
Solution (1/2)
•
This case is for that an AMS is not served by
Non-member AMS
CSG-Closed FBS macro BS, hence the AMS does not have
Receiving SFH,
proper CMAC to use.
A-preamble
MS can judge
• If an AMS is seriously interfered by a
SFH
whether it is a
neighbor CSG-closed femto ABS and cannot
Initial ranging code
member/nonget any service from the network, the MS
RNG-RSP
member of FBS
may request the femto ABS to mitigate the
RNG-REQ, with a purpose bit
based on
interference .
indicating IM
CSGID/BSID
• MS can send an AAI_RNG-REQ message with
Ranging Purpose Indication Bit#5 set as ‘1’.
SBC-REQ/RSP
• Having received this IM indication, the CSGPKM-REQ
closed Femto ABS may further allow MS to
enter the EAP stage for authentication.
Authentication
• If the FBS recognize the AMS is illegal, it
PKM-RSP
rejects any request from MS. If the FBS
recognize that the AMS is a legal user but a
Interference
non-member, the FBS may either accept the
mitigation
IM request, or reject.
• Whether to accept the request of IM or
reject, depends on the FBS service provider
or operator rule.
• Advantage:
– Prevent the CSG femto generating coverage hole
to non-member MS
Solution (2/2)
•
This case is for that an AMS has a proper
Non-member AMS
CSG-Closed FBS CMAC to use.
• This can happen, for example, AMS was in
Receiving SFH,
A-preamble
idle state served by a macro BS, but now it
MS can judge
SFH
whether it is a
cannot hear macro, but only a strong
ranging code
member/noninterference from inaccessible CSG-closed
RNG-RSP
member of FBS
FBS.
based on
• If an AMS is seriously interfered by a
RNG-REQ, with a purpose bit
CSGID/BSID
neighbor CSG-closed Femtocell ABS and
indicating IM. RNG-REQ
contains CMAC
cannot get any service from the network, the
MS may request the femto ABS to mitigate
the interference.
Authenticati
on
• MS can send an AAI_RNG-REQ message with
Ranging Purpose Indication Bit#5 set as ‘1’,
and the CMAC is contained.
RNG-RSP
• The Femto ABS may authenticate the
request.
Interference•
If the FBS recognize the AMS is illegal, it
mitigation
rejects any request from MS. If the FBS
recognize that the AMS is a legal user but a
non-member, the FBS may either accept the
IM request, or reject.
• Whether to accept the request of IM or
reject, depends on the FBS service provider
or operator rule.
Proposed text
Insert the following to page 493, line 48.
If an AMS is seriously interfered by a neighbor CSG-closed
femto ABS and cannot get any service from the network, the
MS may request the femto ABS to mitigate the interference
by sending an AAI_RNG-REQ message with Ranging Purpose
Indication Bit#5 set as ‘1’, to indicate the IM request. Having
received this message, the CSG-closed femto ABS may
further authenticate the AMS. If the FBS recognizes the AMS
is illegal, it rejects any request from MS. If the FBS
recognizes that the AMS is a legal user but a non-member,
the FBS may either accept the IM request, or reject.
Whether to accept or reject the request of IM and how to
mitigate the interference may be up to the service
provider’s policy.