MBS Frame Structure Considerations IEEE 802 16 Presentation

MBS Frame Structure Considerations IEEE 802. 16 Presentation Submission Template (Rev. 9) Document Number: IEEE S 802. 16 m-08/089 Date Submitted: 2008 -01 -16 Source: Wookbong Lee, Dongcheol Kim, Jaho Koo Voice: LG Electronic Inc. LG R&D Complex, 533 Hogye-1 dong, Dongan-gu, Anyang, 431 -749, Korea *<http: //standards. ieee. org/faqs/affiliation. FAQ. html> Venue: Levi, Finland Base Contribution: IEEE C 802. 16 m-08/089 Purpose: For discussion and approval by TGM Notice: +82 -31 -450 -1931 E-mail: wbong@lge. com, Dong. Cheol. Kim@lge. com, Jaho 9@lge. com 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: <http: //standards. ieee. org/guides/bylaws/sect 6 -7. html#6> and <http: //standards. ieee. org/guides/opman/sect 6. html#6. 3>. Further information is located at <http: //standards. ieee. org/board/pat-material. html> and <http: //standards. ieee. org/board/pat >.

Basic numerology Parameter Value : 802. 16 e Reference System CP length CP ratio CP duration 128 1/8 11. 43 μs 64 1/16 5. 71 μs 256 1/4 22. 86 μs OFDM symbol duration 102. 86 μs 97. 14 μs 114. 29 μs # of samples per symbol 1152 1088 1280 # of OFDM symbols per frame 48. 61 51. 47 43. 75 # of data OFDM symbols per frame 44 48 40 # of data slots 660 720 600 Effective frame duration (for fair comparison) 4. 8343 ms 4. 9543 ms 4. 9143 ms Additional simulation assumptions

Effective sample number in MBS environment • Threshold of [-30 d. B]

MBS performance: effect of CP length • 11. 43 us CP ratio is enough even for large ISD

Proposed MBS frame structure Unicast’s CP ratio MBS CP size option / CP ratio (G) Number of unicast OFDM symbols per MBS subframes Number of MBS OFDM symbols per MBS subframes Number of borrowed OFDM symbols Idle time Guni=1/8 11. 43 μs (GMBS=1/8) N N-K K=0 K*NFFT*(1+GMBS)/Fs-NFFT*(GMBS-Guni)/Fs*N [s] Guni=1/16 11. 43 μs (GMBS =1/8) N N-K K = ceil(N/18) K*NFFT*(1+GMBS)/Fs-NFFT*(GMBS-Guni)/Fs*N [s] Since uplink start time for TDD system or preamble start time is well known by MS and BS, so if we put MBS frame at the end of DL frame, MS or BS do not need to do anything with MBS idle time.

MBS feedback (1) • AMC type of operation – slow adaptation • What will be MBS feedback, ex) ACK/NACK or NACK only or else, and How to feedback it is for further study Number of MBS user in a sector Throughput gain 1 3 5 7 10 47% 11. 40% 14. 26% 11. 60% 8. 30%

MBS feedback (2) • With MBS feedback, BS decides to turn on/off hierarchical modulation (HM) • HM turn off BS’s MSs will experience same quality of service as ‘always HM turn off case’, while HM turn on BS’s MSs can get better services

Conclusion • MBS CP duration: 11. 43μs for all cases • MBS subframes shall be located at the end of DL frame • MBS feedback channel shall be considered to improve performance