1. Macro Diversity Handover in Multi-carrier System IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16m-08/1008r1 Date Submitted: 2008-09-16 Source: Yih-Guang Jan, Yang-Han Lee, E-mail: yihjan@yahoo.com Ming-Hsueh Chuang, Hsien-Wei Tseng, Wei-Chieh Tseng, Po-Jung Lin, Ting-Chien Wang Tamkang University (TKU) Shiann-Tsong SheuE-mail: stsheu@ce.ncu.edu.tw National Central University (NCU) Whai-En Chen E-mail: wechen@niu.edu.tw National Ilan University (NIU) Venue: PHY: Multi-Carrier Operation; in response to the TGm Call for Contributions and Comments 802.16m-08/033 for Session 57 Base Contribution: N/A Purpose: Propose a Macro Diversity Handover in Multi-carrier System 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 this contribution we will be based on the standard of 802.16m system to propose the multi-carrier handover process so that this handover mechanism can be selected and implemented into the 802.16m system. In the discussion of multi-carrier handover mechanism we assume in our discussion that the system synchronization has completed therefore the synchronization process will not be discussed in this contribution. We will be in this contribution to utilize the concept of multi-carrier handover to design the macro diversity soft handover technique.

3. Macro Diversity Handover (1/4) The main task of soft handover is to the improve the drawbacks of hard handover and to improve the service quality and to reduce the drop rate. The concept of soft handover is before the MS terminates its connection with the serving BS it needs to manke connection with other BS, in other words in the handover process the MS has connection with more than one BS. In the OFDMS system it can be classified into two categories in the soft handover, namely Macro Diversity Handover (MDHO) and Fast Base Station Switching (FBSS). In considering the technique for multi-carrier HO it is suitable to use the design technique of soft handover process.

4. Macro Diversity Handover (2/4) Either with MDHO or FSBB handover, it will be in the MS to maintain a list of base stations, namely the Diversity Set. In the Diversity Set it will define one BS as an Anchor BS, it has the same function as the serving BS; its main function is to proceed and maintain the information exchange with the MS. By taking MDHO for example, the receiving signal strength of the MS from the outer layer neighboring BS is not strong enough and will not be included in the Diversity Set and consequently the outer layer BSs are not included in the Diversity Set. The MS will communicate with all active BSs in the Diversity Set, in other words, the MS will be simultaneously to transmit or receive data with many BSs.

5. Macro Diversity Handover (3/4) When MS moves, the Active BS list in the Diversity Set is constantly modified through the Anchor BS; when the signal strength of the Active BS becomes weak it will be removed from the list through the Anchor BS, on the contrary when a BS has stronger signal strength it will be included in the Diversity Set through the Anchor BS. The design of soft handover process is suitably implemented with multi-carrier HO technique. The multi-carrier HO can be expanded to three, four or many carriers technique. One of the carrier is used to contact with the Anchor BS while the other carrier is used to contact with the Active BS to complete the soft handover implementation. In the following figure it discusses and models the multi-carrier MDHO process.

6. Macro Diversity Handover (4/4)

7. Conclusion In this contribution we use the multi-carrier handover process to design the soft Macro Diversity Handover, it concludes with a system flow chart as shown in the following figure. It is proposed to be adopted in the 802.16m as its handover algorithm.

8. Text Proposal ===================Start of Proposed Text==================== 19 Support for Multi-carrier 19.x Multi-carrier Handover Method 19.x.1 Macro Diversity Handover The macro diversity handover mechanism with three carriers involved in the handover has the flow chart as shown in the following figure:

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