1. A New Approach for Inter-cell Interference Randomization based on Cell/Sector-specific Interleaver Pattern Document Number: IEEE S802.16m-07_218r5, Date Submitted: 2008-1-17 Source: Yunzhou Li, Shidong Zhou, Xibin Xu, Xin Su, Xiaofeng Zhong, Jing Wang, Xiaolu Dong, Ying Du, Shanpeng Xiao, Wenqi Liao, LianYang, Zhongkai Wang, Weijun Xu, Thomas Li, E-mail:{liyunzhou, zhousd, xuxb, suxin, zhongxf, wangj}@tsinghua.edu.cn, {dongxiaolu, duying}@mail.ritt.com.cn, {xiaoshanpeng, liaowenqi} @chinamobile.com, yang.lian@huawei.com, {wangzk,xwj}@thip.gov.cn, thomasli@legendsilicon.com Tsinghua Univ., CATR, CMCC, Huawei Technologies, Tianjin Municipal Government, Tianjin Hi-Tech Industrial Park, Legend Silicon Corp. Re: TGm Call for comments on SDD, IEEE 802.16m-07/040 Abstract: This document proposes a new approach to randomize inter-cell interference based on cell/sector-specific interleaver pattern. Purpose: This contribution proposes a new approach to randomize inter-cell interference based on cell/sector-specific interleaver pattern. Meanwhile, some simulation results to verify the advantages of the new approach are presented in this contribution, too. 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. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 2 Outline Concept of Cell/Sector-Specific Interleaver Benefit of cell-specific interleaving to Inter-Cell- Interference Conclusion & Proposal to 802.16m SDD

3. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 3 The traditional approaches to inter-cell interference The randomization of ICI is necessary The traditional approaches to ICI include:  Cell-specific scrambling (3GPP downlink)  Frequency Hopping  etc. Channel coding process

4. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 4 Cell-Specific Interleaving The cell-specific interleaving  Different interleave patterns for different cells/sectors  Pattern is pseudo-random generated, determined by seed and interleaver length. Generation and allocation of cell-specific interleaver patterns  A pseudo-random method is proposed in C80216m-07_218r1.doc to generate the cell-specific interleaver pattens  An interleaver patten is completely determined by its generation seed and the length of the interleaver.  The seeds can be reused between “far-spaced” cells in a manner similar to that of frequency reuse in a cellular system. A detailed method is given in C80216m-07_218r1.doc

5. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 5 Benefits from cell-specific interleaving cell-specific scrambling (CDMA) and cell-specific interleaving (IDMA) basically have the same performance for the receiver without iterative detection. cell-specific interleaving obviously outperforms cell-specific scrambling in BER performance with iterative multi-user detection at receiver. The benefit from cell-specific interleaving is very important for broadcasting within each cell, for which other ICI mitigating techniques, such as beamforming or ICI coordinating can’t be implemented.

6. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 6 Comparison between IDMA and scrambling, with iterative receiving Simulation conditions:  AWGN channel,  Three Users (K=3)  QPSK,  convolutional code with constraint length=5  Iterative multi-user detection at receiver with iteration times= 3 Conlusion:  IDMA can distinguish high rate users with iterative receiver, which could not be realized by simple scrambling.

7. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 7 The performance of IDMA and principle Simulation conditions:  Rayleigh channel,  Three Users (K=3)  QPSK,  convolutional code with constraint length=5  Iterative multi-user detection at receiver with iteration times= 3 Conlusion:  The BER performance of multi-user system based on IDMA is approaching that of single user system  High spectrum efficiency at cell/sector edge can be achieved

8. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 8 The performance of IDMA and principle Based on the results presented by the published papers about IDMA and iterative multi- user detection, we can draw the following conclusions:  User-specific interleaving is more helpful than user-specific scrambling to refine the certainty of coded bits of all users.  Rayleigh channel is more favorable to reduce the iterative times of detection for the IDMA-OFDM system, due to the inconsistent fluctuations of the channels of different users

9. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 9 Conclusion and Proposal to 802.16m SDD [Insert the following text into Physical Layer sub-clause (i.e. Chapter 11 in [X]): ------------------------------- Text Start --------------------------------------------------- Cell/sector specified interleaving shall be used to randomize the transmitted signal, in order to support frequency reuse at the cell/sector edge, with more opportunities to achieve high spectrum efficiency by additional algorithm. Different cells or sectors may use different seeds in generating pseudo random interleavers. This interleaver can be also used as channel interleaver, i.e., it is not necessary to apply additional interleavers for interference randomization. [ Insert the section 4 of this contribution: “Generation and allocation of cell- specific interleaver patterns”] In order for much better performance, additional dedicated pilot within data block is optional. ------------------------------- Text End ---------------------------------------------------

10. March 21, 2007, Presentation to Verizon MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All other product or service names are the property of their respective owners. © Motorola, Inc. 2006. 10 10 [Insert the following text into Medium Access Control Sub- Layer sub-clause (i.e. Chapter 10 in [X]): - ------------------------------ Text Start --------------------------------------------------- When cell/sector specified interleaver is being applied, no additional action is mandatory for the MAC sub-layer. However, with the following option supported, much better throughput can be achieved at the cell edge. MAC sub-layer optional operation: Resource allocation alignment among users from adjacent cells, which may interfere with each other. While selecting MCS(modulation and coding rate parameter) of the users at cell edge, which may interfere with each other, taking the knowledge of the processing capability (iterative decoding) of the MTs(reported from MT) into consideration. ------------------------------- Text End --------------------------------------------------- ]