Proposed Change to 8-stream Pilot Patterns (Section 15.3.5.4.1) IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C80216m-09/1737r1 Date Submitted: 2009-08-31 Source: Chung-Lien Ho, Yan-Xiu Zheng, Yu-Chuan Fang, E-mail: clho@itri.org.tw Chang-Lan Tsai, ITRI Pei-Kai Liao, Chih-Yuan Lin, Paul Cheng pk.liao@mediatek.com MediaTek Zhouyue Pi, Jiann-An Tsai Samsung Electronics *<http://standards.ieee.org/faqs/affiliationFAQ.html> Venue: IEEE Session #63, Jeju, Korea Re: IEEE P802.16m/D1. Section 15.3.5.4.1 Base Contribution: N/A Purpose: To be discussed and adopted by TGm for the IEEE P802.16m/D1. 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 >.

Introduction Pilot patterns for 8 data streams in [1] are designed without considering pilot boosting issue Suggested DL power settings for data and pilot subcarriers [2] Table X: DL power settings for data and pilot subcarriers for different number of data streams [2] Number of data streams Mt Per stream power on data subcarriers Per stream pilot power Per stream pilot boosting level, dB 1 - 2 1/Mt 100.2 2 + 10*log10(Mt) 3 - 4 1 0 + 10*log10(Mt) 5 - 8 The DL peak spectral efficiency may support 30 bps/Hz for 8-Tx MIMO with rate up to 8. So based on the throughput requirement, the pilot overhead is an important design issue.

Original pilot patterns for 8 data streams

Pilot boosting level Based on Table X, per stream pilot booting level is 10*log10(Mt) = 6.9897, 7.7815, 8.4510, 9.0309 (dB) for Mt = 5, 6, 7, 8 This may cause OFDM symbol-by-symbol power fluctuation OFDM symbol-by-symbol power fluctuation can be avoided only when Mt = 8 and pilot booting level = 10*log10(4) = 6.0206 dB

Modified pilot patterns for 8 data streams

Pilot boosting level Based on Table X, per stream pilot booting level is 10*log10(Mt) = 6.9897, 7.7815, 8.4510, 9.0309 (dB) for Mt = 5, 6, 7, 8 No OFDM symbol-by-symbol power fluctuation for Mt = 5, 6, 7, 8

Performance Results Simulation parameters Parameter Value Frame Structure 16m frame structure (10 MHz, 1024 subcarriers) OFDM symbols/subframe 6 Permutation None (CRU) Channel model [16m EMD] Ped-B with 3 km/h Veh-A with 30 km/h Channel estimation (CE) 2D-MMSE (CE over 2 CRUs or 4 CRUs), delay spread perfectly known but actual power delay profile unknown Power boosting for level 10*log10(4) = 6.0206 dB for original patterns 10*log10(8) = 9.0309 dB for modified patterns MIMO scheme 8 x 8 spatial multiplexing (8-stream) Channel coding scheme 16e CTC Detection scheme Linear MMSE MCS Set [1] QPSK-101/256, QPSK-171/256, 16QAM-128/256, 64QAM-135/256, 64QAM-181/256, 64QAM-225/256 , 64QAM-237/256 Number of CRUs 2 CRUs or 4 CRUs with rate matching This page shows the simulation parameters. Here we consider 3 channel models: Indoor hotspot, Ped-B and Veh-A. We use the 2D-MMSE CE, and delay spread perfectly known but actual power delay profile unknown. And we use the following MCS set proposed in Reference #1 which has been accepted in the last meeting.

Simulation results Ped-B 3 km/h, CE over 2 CRUs This page shows the throughput performance for indoor hotspot channel with 3 km/h and CE over 2 CRUs. From this figure, we can see that ITRI and MediaTek patterns can indeed achieve the 30 bps/Hz. For single PRU-based CE, the performance is shown in the next page.

Ped-B 3 km/h, CE over 4 CRUs

Veh-A 30 km/h, CE over 2 CRUs For the Veh-A channel with 30 km/h and CE over 2 CRUs, Samsung and Fujitsu patterns can perform better, but the performance no long is good enough.

Veh-A 30 km/h, CE over 4 CRUs But however, ITRI’s patterns can perform better when the CE is done over 4 CRUs. So based on the simulation results, we would like to propose our ITRI’s pilot pattern to 16 AWD.

Conclusion The proposed pilot pattern provides the gain in terms of throughput comparing to existing 8 Tx pilot pattern The pilot pattern also resolves power fluctuation problem We would like to modify the 8TX pilot pattern in IEEE P802.16m/D1 by the new proposed pilot pattern

References [1] IEEE P802.16m/D1, “DRAFT Amendment to IEEE Standard for Local and metropolitan area networks, Part 16: Air Interface for Broadband Wireless Access Systems,” July 2009. [2] IEEE C802.16m-09/1681, “Proposed Changes to Pilot Patterns Boosting Values (15.3.12.2.7) for the IEEE 802.16m/D1,”

Proposed Text Replace Figures 422 by following figures This page shows the proposed text for the 8-Tx pilot pattern! That’s it! Thank you!