Precoder cycling duration for nonadaptive precoding IEEE 802

Precoder cycling duration for non-adaptive precoding IEEE 802. 16 Presentation Submission Template (Rev. 9) Document Number: IEEE C 80216 m-09_0662 Date Submitted: 2009 -03 -08 Source: Wookbong Lee and Bin-Chul Ihm LG Electronics wbong@lge. com Venue: IEEE 802. 16 m Session#60, Vancouver, Canada Call for Comments on IEEE 802. 16 m-09/0010 IEEE 802. 16 m Amendment text Base Contributions: N/A Re: Purpose: To discuss and adopt in 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: <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 >.

Overview • In current document, – With non-adaptive precoding, the precoder W is predefined and selected from the base codebook or its subset. The changes of the precoder W are [TBD]. – There are two candidates: N 1 or N 2 • In 16 m, there are three types of permutation – DRU: diversity mode (MFM 0) – PRU based CRU: diversity mode (MFM 1) – Subband based CRU: localized mode (MFM 3) • In this contribution, we show which precoder cycling duration is proper for all of these permutation • All of simulation conditions can be found in C 80216 m 09/0385

Diversity mode, DRU (MFM 0) SFBC with precoder (MM 0)

Diversity mode, PRU based CRU (MFM 1) SFBC with precoder (MM 0)

Diversity mode, DRU (MFM 0) SM with precoder (MM 1)

Diversity mode, PRU based CRU (MFM 1) SM with precoder (MM 1)

Link adaptation mode, Subband based CRU (MFM 3) rank-1 precoder and SM with precoder (RA) (MM 1) Uncorrelated Channel Highly correlated Channel [2 Tx, 2 Rx] N 1 granularity N 2 granularity Normalized Spectral Efficiency 100 98. 4 Normalized Cell Edge throughout 100 96. 3 Normalized Spectral Efficiency 100 88. 5 Normalized Cell Edge throughout 100 77. 8

Discussion 1/2 • Problem of logical index cycling – In DRU, pilots will be shared by different LRUs • The pilot can’t be precoded with logical index cycling pilot overhead reduction gain is disappeared • If we use same precoder for PRU, logical index precoding will be end up very small number of precoder cycling reduce diversity gain • Problem of N 2 cycling – Miniband will be used for link adaptation mode (MFM 3) as well as diversity mode (MFM 1) • In link adaptation mode (MFM 3), subband CQI will be used for scheduling miniband N 2 cycling has CQI mismatch due to different precoders are allocated to different miniband within a subband • Problem of time domain cycling – In link adaptation mode (MFM 3), different precoder for different subframe will reduce performance as same reason as N 2 cycling – MS will be allocated to one subframe or two subframe CQI mismatch or Feedback overhead increase

Discussion 2/2 • In diversity mode, the performance of N 1 cycling and N 2 cycling is almost same • In link adaptation mode, N 1 cycling outperforms N 2 cycling • In subband CRU, multiple PRU (N 1) channel estimation can be done with N 1 granularity • Remedy: Propose to select N 1 cycling (Modify texts in C 802. 16 m-09/0513 – proposed text of MIMO for the IEEE 802. 16 m amendment) – (In recommended text proposal #5) With non-adaptive precoding, the precoder W is predefined and selected from the base codebook or its subset. The changes of the precoder W are [TBD], and it changes every N 1 contiguous PRUs. – (In recommended text proposal #6) With non-adaptive precoding, the precoder W is predefined and selected from the base codebook or its subset. The changes of the precoder W is [TBD], and it changes every N 1 contiguous PRUs.