1. A New Approach for Inter-cell Interference Randomization based on Cell/Sector-specific Interleaver Pattern Document Number: IEEE S802.16m-07_218, Date Submitted: 2007-11-13 Source: Yunzhou Li, Xibin Xu, Xin Su, Xiaofeng Zhong, Shidong Zhou E-mail:{liyunzhou, xuxb, suxin, zhongxf, zhousd}@tsinghua.edu.cn Tsinghua Univ. 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 IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs 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 The traditional approaches to randomize the inter-cell interference The proposed approach to ICI What is the benefit from cell-specific interleaving? The performance of IDMA and principle 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 The proposed approach to ICI The cell-specific interleaving Coded bit-level interleaving Dont need channel interleaver 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 What is the benefit from cell-specific interleaving? cell-specific scrambling 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 when iterative multi-user detection is used in receiver. The benefit from cell-specific interleaving is very important for broadcasting, for which other ICI mitigating techniques, such as beamforming or ICI coordinating cant be implemented. Moreover, saving energy by reducing RF operating

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 The performance of IDMA and principle Simulation conditions: Rayleigh channel, Three Users (K=3) QPSK, convolutional code with constraint length=5 Iteration times= 3 Conlusion: In conclusion, the BER performance of multi-user system based on IDMA is approaching that of single user system

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 Assumption: channel coefficient BPSK for two users System Model Best case:

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 worst case: But, if the prior information about b0 and/or b1 is derived from FEC decoder, it is easily to further increase the certainty about b0 and b1

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 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

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 Conclusion and Proposal to 802.16m SDD [ The following text proposal is suggested by this contribution: cell/sector-specific interleaving shall be considered in SDD as an approach to randomize and mitigate the inter-cell interference ]