C802.16m-08/589
Project
Title
Date
Submitted
Source(s)
Re:
Abstract
IEEE 802.16 Broadband Wireless Access Working Group < http://ieee802.org/16 >
ToC Proposal for Interference Mitigation in SDD
2008-07-08
Choong Il Yeh, Young Seog Song, Seung Joon Lee,
Byung-Jae Kwak, Jihyung Kim, Min Sik Seo, Wooram Shin,
Dong Seung Kwon
ETRI 161 Gajeong-dong Yuseong-gu, Taejeon 305-700,
Korea
Voice: +82 42 860 4895 (Choong Il Yeh)
+82 42 860 5936 (Dong Seung Kwon)
E-mail: ciyeh@etri.re.kr
(Choong Il Yeh) dskwon@etri.re.kr
(Dong Seung Kwon)
Hyoungjin Choi
TTA
267-2, Seohyeon-dong, Bundang-gu,
Seongnam-si, Gyeonggi-do, 463-824,
Korea ibm686@tta.or.kr
IEEE 802.16m-08/024: Call for Contributions on Project 802.16m System Description Document (SDD) (2008-06-18), Interference
Mitigation.
ToC for interference mitigation under universal or aggressive frequency reuse is proposed.
Purpose
Notice
Release
Patent Policy
Adoption of proposed text into SDD
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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>.
Further information is located at < http://standards.ieee.org/board/pat/pat-material.html
> and
< http://standards.ieee.org/board/pat >.

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C802.16m-08/589
Problem Statement
Universal or aggressive frequency reuse in upcoming OFDMA systems including TGm cause very severe inter-cell interference especially in the cell boundaries and limit system capacity.
What should we do?
In order to mitigate inter-cell interference and to improve system performance not only PHY/MAC layer but also Inter-BS coordination should be specified in SDD.

C802.16m-08/589
11.x Interference Management
11.x.1 Inter-cell Coordination
[FFR, power control, and Multi-cell MIMO are the key factors to mitigate intercell interference. Inter-BS coordination is indispensible to support these functionalities.]
11.x.2 Logical Control Channels
[DL and UL control channels for resource allocation and for carrying required measurements may be necessary.]
11.x.3 Interference Randomization
[Allocating subcarriers into a subchannel, the adjacent cells permute them differently in order to guarantee minimum subcarrier-hit probability. But when applying FFR where some of the subcarriers are not used to reduce inter-cell interference, the subcarrier permutation may not be necessary. With the absence of permutation in FFR, there is no subcarrier hit and therefore no intercell interference between neighbors. But with the permutation, there still exists inter-cell interference due to the subcarrier-hit.]

C802.16m-08/589
11.x.4 FFR
11.x.4.1 Hard FFR
[Some of the tones can not be used to mitigate inter-cell interference.]
11.x.4.2 Soft FFR
[To mitigate inter-cell interference the power of some of the tones can be adjusted (reduced) rather than not used. Uplink power control considering the neighbor cells’ overload condition falls into soft FFR.]
11.x.5 Multi-cell MIMO
[Network coordinated BF, precoding, or interference nulling shall be supported to mitigate inter-cell interference. A multi-cell MIMO zone can be configured in a frame to support multi-cell MIMO transmission.]

[1] IEEE 802.16m-07/002r4, “TGm System Requirements Document (SRD)”
[2] IEEE 802.16m-08/004r2, “TGm Evaluation Methodology Document”
[3] IEEE 802.16m-08/003r3, “Draft IEEE 802.16m System Description Document”
C802.16m-08/589