1. Some Considerations about 16m Network Architecture Document Number: C80216m-08_491 Date Submitted: 2008-5-8 Source: Qu Hongyun, Fang Huiying, Liu Yang, Chen Yuqin Sean Cai, Jerry Chow, Xu Ling E-mail: qu.hongyun@zte.com.cn * http://standards.ieee.org/faqs/affiliationFAQ.html Venue: To Response “Call for Contributions on Project 802.16m System Description Document (SDD) – pertaining to comment on entire content of IEEE 802.16m-08/003r1.” Base Contribution: Purpose: To be accepted by TGm. 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. Introduction In current SDD document 802.16m-08_003r1, the section 4 describes the overall network architecture for 16m system, including the air interface with relay station, as the following figure.

3. Problems Problem-1 –If 16m BS can operate with 16j RS, it means 16m BS has to include the capabilities same with 16j BS, which is referred to MR-BS in current 16j draft standard. In other words, 16m BS has to backward support reference system with functionalities to support 16j RS. –Actually according to the legacy supporting requirement in 16m SRD, the legacy reference system is defined by WiMAX Mobile System Profile, which does not include the definition of 16j BS. –So if 16m BS can operate with 16j RS, the capability of backward compatibility of 16m BS is extended to support 16j BS. It is not a requirement of 16m SRD. And it will cause high complexity for 16m BS, because 16m BS has to support at least three air interfaces, including16e, 16j, and 16m. If the air interfaces between 16mMS-16mBS and 16mRS- 16m BS are different, then 16m BS has to support four air interfaces. Problem-2 –From another perspective, in current 16j draft standard, there is a lot of optional features to support the same functionality. It does not meet the complexity requirements of 16m for minimum optional features. Problem-3 –Currently 16jm adhoc suggest to support the connection between 16m BS and 16j RS under such a assumption that a 16j relay profile will be defined, which is not necessary in IEEE 802.16 WG. –We do not think this assumption makes sense. Obviously, IEEE 802.16 WG will not define this 16j relay profile. And actually the activities outside of IEEE 802.16 WG can not be controlled by IEEE 802.16 WG.

4. Our Opinion Our suggestion is as follows. –16m BS should not support 16j RS. –16m RS may support legacy 16e MS. –Referring to the design schemes currently in 16j draft standard as many as possible, when 16m RS is designed. Reason: –It will reduce the implementation complexity of 16m BS, compared with 16m BS with supporting 16j RS. –It will reduce the redundancy of relay station, because 16m RS will be defined and it can support both 16e MS and 16m MS.

5. Text Proposal To replace the Figure 2 in the Section 4 with the following Figure:

6. Text Proposal To replace the current paragraph below the Figure 2 in the Section 4 with the following text: A 16m RS that is capable of supporting a legacy MS, shall communicate with the legacy MS in the "legacy zone". The design of 16m relay protocols should refer to the design of 16j wherever possible.