1. Proposed changes for IEEE P802.16m/D1: 15.4.8.1 Proximity based handover from macrocell to femtocell IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C80216m-09/1909 Date Submitted: 2009-08-28 Source: Yongseouk Choi, Raunak Maheshwari, Nak Wook Sung, Voice: +82-42-860-5679 Namsuk Lee, Jisoo Park, Sookjin Lee ETRI E-mail: {raunak,choiys,nwsung, namsuk,jsp, sjlee}@etri.re.kr 138 Gajeongno, Yuseong-gu, Daejeon, 305-700, KOREA * http://standards.ieee.org/faqs/affiliationFAQ.html Venue: IEEE 802.16 Session #63, Jeju, Republic of Korea (South) Base Contribution: None Purpose: To discuss and adopt the proposed text in the next revision of the P802.16m/D1 Notice: 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. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.16. Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: and.http://standards.ieee.org/guides/bylaws/sect6-7.html#6http://standards.ieee.org/guides/opman/sect6.html#6.3 Further information is located at and.http://standards.ieee.org/board/pat/pat-material.htmlhttp://standards.ieee.org/board/pat

2. Contents 1.Handover triggers 2.Proximity based handover scheme 3.Draft Text

3. Handover Triggers Triggers supported in the SDD are Signal Strength Proximity of the MS to the Femtocell BS Loading In this contribution we propose a text to for Proximity based handover scheme

4. Proximity based handover scheme Proximity of MS to Femto BS has to be detected. This can be done by Femto BS by analyzing received signals. FBS knows channel information of MS’ already associated with it From received signal it can distinguish the transmitted signals from associated MS’ But if MS not associated with FBS enters the coverage area of FBS, during uplink it causes additional interference at FBS as its channel information is not known. FBS

5. Proximity based handover scheme Once the Femto BS is able to detect an outsider device, there are two ways to handle the situation depending on whether or not the Femto BS has knowledge of Macro BS’ UL Map. Femto BS sends interference report for the duration of the interference experienced by it to the Macro BS. It may send access information (CSG list etc) if available The Macro BS finds out the list of the MS transmitting during that time and page the MS’ for handover. The paging message will contain information for enabling fast handover. Interference detection Interference report Handover instruction MSFBSMBS Data Transfer Handover and data transfer

6. Proximity based handover scheme In case the Femto BS has knowledge of UL Map of Macro BS, it will send the MCRC codes in the interference report. The MCRC codes will be retrieved from the UL map according to the duration of the Interference experienced by the Femto BS. Macro BS will find out the list of the MS by processing the information sent to it by the Femto BS In case the Femto BS has no knowledge of UL Map of Macro BS, it will send the duration/timing information to the Macro BS which will find the list of the MS transmitting during that duration from the UL Map. References [1] IEEE 802.16m-09/0034, “IEEE 802.16m System Description Document (SDD)”

7. Draft text 15.4.8.1.1 Proximity based handover 15.4.8.1.1.1 – FBS knows UL-MAP information If Femto BS detects presence of an unassociated MS in its coverage area due to interference caused by uplink signal from an unassociated MS to Macro BS, it will shortlist the MCRC from the UL-MAP information depending on the duration of the interference experienced. This list will be sent to Macro BS for processing and identification of MS’ transmitting in that duration. 15.4.8.1.1.2 – FBS doesn’t know UL-Map information If Femto BS detects presence of an unassociated MS in its coverage area due to interference caused by uplink signal from an unassociated MS to Macro BS, it will send the timing and duration information to Macro BS for processing for identification of MS’ transmitting during that time. In both the cases, after the Macro BS identifies the MS(s) it will instruct the identified MS’ for handover using AAI_BSHO-CMD message. The MS’ on receiving the AAI_BSHO-CMD message will scan for the target Femto BS. On finding the target Femto BS, re-entry process will start and if the target Femto BS is not found, it will send AAI_HO-IND message with event code of 0b01 (all target BS unreachable)

8. The figure details the handover procedure Interference detection Interference report AAI_BSHO-CMD MS Target Femto BS Serving Macro BS Established Data Path Network re-entry to Target Femto BS AAI_HO-IND HO Complete Data path established Process report & make list