1. Radio Resource Allocation for Multi-radio Coexistence IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16m-08/882 Date Submitted: 2008-08-31 Source: Feng Seng ChuGraduate Institute of Communication EngineeringE-mail: b8901009@ee.ntu.edu.twb8901009@ee.ntu.edu.tw Kwang Cheng ChenGraduate Institute of Communication EngineeringE-mail: chenkc@cc.ee.ntu.edu.twchenkc@cc.ee.ntu.edu.tw Neeli PrasadAalborg University E-mail: np@es.aau.dknp@es.aau.dk Ramjee PrasadAalborg University E-mail: prasad@kom.aau.dkprasad@kom.aau.dk Kanchei (Ken) LoaInstitute for Information IndustryE-mail: loa@iii.org.twloa@iii.org.tw Venue: IEEE 802.16 Interim, Session #57, Kobe, Japan Purpose: Propose radio resource allocation as collaborative and non-collaborative coexistence mechanism. 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. Necessity of Coexistence Mechanism Officially, according the LMSC P & P [1] ▫For a wireless project to be authorized, the WG is required to produce a Coexistence Assurance (CA) document to be submitted with their draft unless there is a compelling reason to omit this step. Furthermore, Section 8.3 in 802.16m SRD [2] ▫Methods to avoid being the victim or source of interference when co-deployed with legacy non- IEEE 802 (3GPP, CDMA2000, TD-SCDMA, etc.) and IEEE 802-based systems (802.16, 802.15, 802.11, 802.22, etc) are required.

3. Necessity of Coexistence Mechanism (2) Technically, we need such mechanisms to achieve reliable and quality communications by avoiding interference among systems ▫1. operating in overlap/adjacent un-license bands. ▫2. as secondary in license bands. Please note, what we consider now is next generation high-bandwidth-efficiency wireless technologies, only (MIMO) OFDMA based systems is targeted.

4. What’s mechanism we consider? Since existing pure physical and MAC approaches are neither effective nor scalable with number of radios and number of vendors. From section 6.4 in 802.16m SRD [2] ▫Resource management to support efficient utilization of system resources and to reduce interference are required. We consider radio resource allocation (RRA) as our critical mechanism.

5. What’s the benefit? From many existing researches, RRA can largely improve system capacity by dynamic allocating OFDMA time slots and subcarriers among users. However, the significance of RRA for coexistence is NOT only to transform this increased capacity to system throughput or user data rate, but is to realize reliable communications and guarantee quality service under such unsure operating environments by this increased capacity.

6. What’s the benefit? (2) In additions, by adaptively utilizing system resource, scalability and flexibility of 4G requirements can be satisfied. Furthermore, such increased capacity can also be used to ▫1. enlarge cell coverage. ▫2. Better support mobility. ▫3. keep as margin for backup. ▫4. ……

7. Different types of coexistence According to IEEE 802.15.2 [3] ▫Collaborative and Non-collaborative ▫Collocation and Non-collocation For us, collocation is not the point because the RRA should be implemented at BS, we tend to view the collocated standards in user terminal as independent clients. In the following we propose RRA for ▫1. Non-collaborative coexistence. ▫2. Collaborative coexistence.

8. RRA for Non-collaborative scenario For systems operating in un-license band or as secondary in license band, we at least need the following three general functions. ▫1. Channel Identification. ▫2. Feedback. ▫3. Radio Resource Allocation. In this contribution we assume feedback channel is perfect.

9. General System Operations BS MS 1. Identify available subcarrier now by proposed composite hypothesis test. Channel Identification Algorithm 2. Estimate required CSI of available subcarriers. Feedback CSI of available sub-carriers RRA Algorithm Data Traffic Optimal or Low-complexity 3. Predict available subcarriers and their CSI in next frame.

10. Channel Identification Example Generalized Likelihood Ratio test

11. Radio resource allocation Example cc After collect above information from all user, the base station can allocate available time slots and subcarriers of each user among all users. :un-available subcarrier :available subcarrier User 1 cc User 2 cc User 3 Power is also considered in allocation.

12. Radio Resource Allocation Example Such a multi-variable non-linear optimization is hard to be solved. A low-complexity but sub-optimal algorithm may be preferred. Subcarrier allocation index for user u, time slot t and subcarrier k Power allocated to subcarrier k in time slot t Channel to noise ratio

13. Low-complexity Algorithm Example We can divide the optimal allocation into ▫1. time-frequency subcarrier allocation. ▫2.Power allocation. By subcarriers allocation resulted in prior step. Allocate power among subcarriers Uniformly distribute power Allocate subcarriers

14. Numerical Result (1)

15. Numerical Result (2)

16. Numerical Result (3)

17. RRA for collaborative scenario Now there are information exchange among coexisting systems, we can consider a more aggressive scheme such as ▫Cross-Three-Layer Radio Resource Allocation.

18. Fundamental Idea Traditionally, frequency reuse are network layer issue and not included in MAC-PHY RRA. However, if the information exchange among BSs are possible, dynamic allocate spectrum among cells become possible. Actually, this scheme should be more considered when coexisting BSs are collocated.

19. Problem Formulation Spectrum allocated to cell i

20. System Architecture

21. Problem Formulation (2) Furthermore, with different assumptions the resulted capacity formulation of each systems are different. For example, if we assume MIMO-OFDMA systems, the system capacity can be

22. Problem Formulation (3) Apparently, the definition of SNR is direct relate to the receiver structure and channel assumption. We can formulate a cross-three-layer RRA by prior description.

23. Numerical Result

24. Contributions We propose RRA as critical coexistence mechanism. Algorithms for two different coexistence scenarios are demonstrated. Both the algorithms can largely increase system capacity from fixed resource allocation, we can utilize this increased capacity to realize reliable communication. Since resource are adaptive allocated, scalability can be also satisfied.

25. Reference [1] IEEE PROJECT 802 LMSC POLICIES AND PROCEDURES, January, 2006. http://ieee802.org/policies-and-procedures.pdf.http://ieee802.org/policies-and-procedures.pdf [2] “Project 802.16m System Requirements Document (SRD),” October, 2007. http://www.wirelessman.org/tgm/docs/80216m- 07_002r4.pdf.http://www.wirelessman.org/tgm/docs/80216m- 07_002r4.pdf [3] IEEE 802.15.2/D09, March 2003, http://myurl.com.tw/6gus.http://myurl.com.tw/6gus