An interference mitigation framework in femtocell (P80216m/D3-16.4.11) Document Number: IEEE C802.16m-09_2679 Date Submitted: 2009-12-29 Source: Kanchei(Ken) Loa, Yi-Ting Lin, Tsung-Yu Tsai, Yung-Lan Tseng, Chun-Yen Hsu, Chiu-Wen Chen E-mail: loa@iii.org.tw, eating@nmi.iii.org.tw Institute for Information Industry (III) Venue: Base Contribution: N/A Re : P802.16m/D3 Purpose: Discussion and approval of the proposal into the IEEE P802.16m/D3 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 802.1 Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: <http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>. Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.

Introduction In this contribution, we propose an interference mitigation (IM) framework with the following features: Could operate under current PHY structure of 802.16m Limit the additional modification and complexity of the PHY structure of femtocell. Flexibility to accommodate different interference mitigation schemes or algorithms The choosing and operating of interference mitigation schemes in femtocells have limited effect to the operation of AMSs.

Proposed Interference Mitigation Framework The proposed IM framework considers two main categories of interference in femtocells The interference between femtocells and overlapping macrocells The interference between femtocells

IM between macrocell and femteocell If the DFPC of overlapping macrocell(s) is not equal to 0 the Femto ABS is able to obtain the frequency partitions information of the overlapping macro ABS via either the SFH transmitted by the overlapping macro ABS or wireline backhaul. Femto ABS can avoid scheduling data or control messages (e.g. A-MAP) in the occupied frequency partitions of the macro ABS (i.e. frequency partition with high power) to evade the interference. For the case that macrocell’s DFPC is 1~6, there is always two frequency partitions which have lower interference from the overlapping macrocells.

IM between femtocells Regardless the actual interference mitigation scheme performed in the backhaul, the Femto AMS receives/transmits data or control messages according to the received A-MAP. The interference of data could be evaded by scheduling. The signaling overhead for IM in the air link is minimized. The location of A-MAP region of femtocell is in the first DRUs of one of the frequency partition The Femto ABS transmits A-MAP in chosen frequency partition The location of A-MAP region may be semi-static and switched to different frequency partitions. The femto AMS could blindly decode the non-user-specific A-MAP in each frequency partition and detect the existence of A-MAP via the CRC in the non-user-specific A-MAP. Since DRU is permutated in a cell-specific manner, when the non-user-specific A-MAP is detected (via CRC) in a frequency partition, the cell which transmits the A-MAP is also identified. After non-user-specific A-MAP is detected, the Femto AMS continues to decode remaining part of the A-MAP region to obtain the scheduling information of this subframe.

Proposed text [Add the following text in the section 16.4.11 on page 604 (line 11) as shown below] The Femto ABS transmits A-MAP in selected DL subframes and frequency partitions. When the A-MAP is transmitted by a Femto ABS in a DL subframe, it appears in the first DRUs of the selected frequency partition.