1. Radio Resource Allocation for Multi-radio Coexistence IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16m-08/882r1 Date Submitted: 2008-09-05 Source: Feng Seng ChuNational Taiwan University E-mail: b8901009@ee.ntu.edu.twb8901009@ee.ntu.edu.tw Kwang Cheng Chen National Taiwan University E-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 Industry E-mail: loa@iii.org.twloa@iii.org.tw Venue: IEEE 802.16 Interim, Session #57, Kobe, Japan PHY aspects of Multi-Radio Coexistence; in response to the TGm Call for Contributions and Comments 802.16m-08/033 for Session 57 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. Outline Multi-radio Coexistence Classification of Multi-radio Coexistence – Collaborative/Non- collaborative – Collocation/Non- collocation Proposed Solution Realization based 16m SDD Example Algorithms in Function Block Proposed Text

3. Multi-radio Coexistence In 802.16m SRD, Section “Co-deployment with other networks” [1] – It is anticipated that IEEE 802.16m is to be deployed in the same (on a co-channel and non- co-channel basis) or adjacent RF bands as non IEEE 802.16m legacy networks. – The 802.16m standard shall provide a method to avoid generate or suffer interference to/from other coexisting systems.

4. Classification of Multi-radio Coexistence Collaborative/Non-collaborative [2] – There is information exchange among coexisting systems. Collocation/Non-collocation [2] – When two devices’ antennas are positioned less than 0.5 meters apart. In this contribution we focus on – 1. Non-collaborative non-collocation coexistence. – 2. Collaborative non-collocation coexistence.

5. Proposed Solution 16m and non 16m systems may be deployed in the same licensed band [section 9.3, 1], however, interference among systems should be avoid. 16m shall enable the advanced RRM for efficient utilization of radio resources [section 6.4, 1]. Radio resource management/allocation (RRM and RRA) can satisfy both requirements. – Avoid interference among systems. – Significant capacity improvement to achieve reliable communications by efficient resource utilization.

6. Non-collaborative Non-collocation Coexistence General operations BS MS 1.Identify available subcarriers. Spectrum Sensing 2. Estimate CSI of available subcarriers. Feedback CSI of available sub-carriers RRA Data Traffic Optimal allocation or Low-complexity 3. Predict available subcarriers and their CSI in next frame.

7. 16m Protocol Structure

8. Processing Flow Radio Resource Management Multi-Carrier System Configuration Management Scheduling and Resource Multiplexing PHY Control - interference and CQI measurement Control Signaling RRCM MAC

9. Key Operations PHY control – interference and CQI measurement – Identify available subcarriers. – Estimate CSI of available subcarriers. – Predict available subcarriers in next frame. – Predict CSI of next frame available subcarriers. Radio resource management, Scheduling and Resource Multiplexing – Properly allocating system resource among user to maximize system capacity while avoiding interference

10. Example Algorithm to Identification of Subcarrier Status Generalized Likelihood Ratio test

11. Other Example Algorithms in PHY To estimate CSI of available subcarriers – Least-square or LMMSE [3] To predict available subcarriers in next frame – Based on HMM [4] To predict CSI – Linear prediction [5]

12. Properly Allocating System Resource cc After collecting above information of all user by PHY control function block, do RRM and SRM. :un-available subcarrier :available subcarrier User 1 cc User 2 cc User 3

13. Example Algorithm for Radio resource allocation Such a multi-variable non-linear optimization is hard to be Solved, low-complexity 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

14. Another Choice: Low-complexity Algorithm 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

15. Numerical Result (1)

16. Numerical Result (2)

17. Numerical Result (3)

18. Collaborative Non-collocation Coexistence Since there are information exchange among coexisting systems, we can consider a more aggressive scheme – Cross-Three-Layer Radio Resource Allocation by including frequency allocation among cells. Inter-BS coordination function are included.

19. Processing Flow based on 16m SDD Radio Resource Management Multi-Carrier System Configuration Management Scheduling and Resource Multiplexing PHY Control - CQI measurement Control Signaling RRCM MAC Inter-BS coordination

20. Resource Management/Allocation Spectrum allocated to cell i

21. Resource Management/Allocation Furthermore, with different assumptions the resulted capacity of each systems are different. For example, if we assume MIMO-OFDMA systems, the system capacity can be Depend on decoding scheme and channel assumption

22. Numerical Result

23. Note Resource should be allocated to users according to resource allocation unit defined in SDD [6]. The proposed RRA algorithm can be slight modified to fit 16m system PHY configuration.

24. Contributions We propose RRA as critical mechanism for multi-radio coexistence. Both non-collaborative / collaborative non- collocation scenario were considered. Processing flow based on 16m SDD. Example algorithms for each function block.

25. Proposed Text 17.x Solutions for Co-deployment and Co-existence – For avoiding interference to/from coexisting systems, flexibly adjusting system usage spectrum is a critical characteristic of coexistence mechanism. Furthermore, to achieve reliable communication under such scenario, efficiently utilizing system resource is also essential. Radio resource management/allocation is a well-known approach satisfying both the two requirements. By properly integrating the capability of existing function blocks in 16m protocol structure, the proposed mechanism can be realized effectively.

26. 17.x.1 RRA for Non-Collaborative Non-collocation Multi-Radio Coexistence – Since there is no information exchange among coexisting systems for this scenario, the function block “PHY Control - interference measurement” is required. – There should be at least two step in this function, (i) identify each subcarrier status of each user. (ii) Predict each subcarrier status in next frame of each user. – For resource allocation, the function block “PHY Control – CQI measurement/feedback” is required. – According to RRA algorithm adopted, the required CSI or CQI should be estimated and predicted in this function block. – Both the two function blocks “Radio resource management” and “Scheduling and resource multiplexing” are required to properly avoid interference and optimize system performance by information mentioned above. – In order to dynamic adjust system spectrum, both the “Multi-carrier” and “system configuration management” function blocks are required. 17.x.2 RRA for Collaborative Non-collocation Multi-Radio Coexistence – Since there is information exchange among coexisting systems for this scenario, interference measurement is not necessary and we can further improve system performance by integrating frequency allocation among cells into resource allocation to formulate an aggressive Cross-Three-Layer scheme. – To realize this idea, inter-BS function block should be considered.

27. Reference [1]“Project 802.16m System Requirements Document (SRD),” August, 2008. http://www.wirelessman.org/tgm/docs/80216m-07_002r5.pdf. http://www.wirelessman.org/tgm/docs/80216m-07_002r5.pdf [2]IEEE 802.15.2/D09, March 2003, http://myurl.com.tw/6gus.http://myurl.com.tw/6gus [3]Morelli M, Mengali U, “A comparison of pilot-aided channel estimation methods for OFDM systems,” Signal Processing, IEEE Transactions on, Volume 49, Issue 12, page(s): 3065-3073. [4]Akbar, I.A.; Tranter, W.H., “Dynamic spectrum allocation in cognitive radio using hidden Markov models: Poisson distributed case,” SoutheastCon, IEEE, March 2007 Page(s):196 – 201. [5]Akhtman J., Hanzo L., “Channel Impulse Response Tap Prediction for Time-Varying Wireless Channels,” IEEE Trans. on Vehicular Technology, Vol. 56, Issue 5, Part 1, 2007 Page(s):2767 – 2769.Issue 5 [6]“Draft IEEE 802.16m System Description Document,” July, 2008, http://wirelessman.org/tgm/docs/80216m-08_003r4.zip http://wirelessman.org/tgm/docs/80216m-08_003r4.zip