Interference mitigation to support overlaid CSG-closed femto ABS Document Number: IEEE C80216m-09_2596 Date Submitted: 2009-11-06 Source: Ying Li, Baowei Ji, Zhouyue Pi, Youngkyu Baek, Jung Je Son, Anshuman Nigam Email: yli2@sta.samsung.com Phone: +1-972-761-7903 Samsung Electronics Venue: IEEE Session #64 Base Contributions: Re: Contribution in support of a comment on LB30a Purpose: Notice: Discussion and Approval This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein. 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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 551, line 23 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.