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Precoder cycling duration for non-adaptive precoding IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C80216m-0 9 _0662 Date Submitted: 2009-03-08 Source: Wookbong Lee and Bin-Chul Ihm wbong@lge.com LG Electronics Venue:
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Precoder cycling duration for non-adaptive precoding • IEEE 802.16 Presentation Submission Template (Rev. 9) • Document Number: • IEEE C80216m-09_0662 • Date Submitted: • 2009-03-08 • Source: • Wookbong Lee and Bin-Chul Ihm wbong@lge.com • LG Electronics • Venue: • IEEE 802.16m Session#60, Vancouver, Canada • Call for Comments on IEEE 802.16m-09/0010IEEE 802.16m 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/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>. • Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat>.
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: N1 or N2 In 16m, there are three types of permutation DRU: diversity mode (MFM 0) PRU based CRU: diversity mode (MFM 1) Subband based CRU: diversity 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 C80216m-09/0385 Overview
Diversity mode, PRU based CRU (MFM 1)SFBC with precoder (MM 0)
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)
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 N2 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 N2 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 N2 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 N1 cycling and N2 cycling is almost same • In link adaptation mode, N1 cycling outperforms N2 cycling • In subband CRU, multiple PRU (N1) channel estimation can be done with N1 granularity • Remedy: Propose to select N1 cycling (Modify texts in C802.16m-09/0513 – proposed text of MIMO for the IEEE 802.16m 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 N1 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 N1 contiguous PRUs.