WWiSE Pilot Scheme Performance January 2005 doc.: IEEE 802.11-05/1616r0 January 2005 WWiSE Pilot Scheme Performance Date: 2005-01-14 Authors: Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) 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 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <stuart.kerry@philips.com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>. Allert van Zelst, Airgo Networks Allert van Zelst, Airgo Networks

January 2005 doc.: IEEE 802.11-05/1616r0 January 2005 Abstract The goal of this presentation is to show that the pilot scheme proposed by WWiSE outperforms the pilot scheme of 802.11a. This is shown by comparing the performance loss due to timing, frequency offset estimation, and pilot processing of 802.11a with that of WWiSE for the same average SNR per receive antenna. Furthermore, to only consider the effect of the pilot processing, the post-processing SNRs of the pilot processing of 802.11a and WWiSE are compared. It is concluded that the pilot scheme of WWiSE in its mandatory configuration outperforms the pilot scheme of 802.11a. Allert van Zelst, Airgo Networks Allert van Zelst, Airgo Networks

January 2005 Introduction The goal of this presentation is to show that the pilot scheme proposed by WWiSE outperforms the pilot scheme of 802.11a. Since the pilot scheme of 802.11a is standardized, its performance is considered acceptable. So, WWiSE has selected it as reference. Allert van Zelst, Airgo Networks

January 2005 802.11a Pilot Scheme The pilot scheme of 802.11a is Tone Symb.1 Symb.2 Symb.3 Etc. -21 1 1 1 ... -7 1 1 1 ... 7 1 1 1 ... 21 -1 -1 -1 ... Note that above notation does not include the pseudo random sequence pn as defined in Section 17.3.5.9 of IEEE Std 802.11a-1999. Allert van Zelst, Airgo Networks

January 2005 WWiSE Pilot Scheme The pilot scheme of WWiSE for the 2 transmitter (TX) 20 MHz mode is ([1]) For TX1: Tone Symb.1 Symb.2 Symb.3 Etc. -21 1 1 1 ... 21 1 1 1 ... For TX2: Tone Symb.1 Symb.2 Symb.3 Etc. -21 1 -1 1 ... 21 -1 1 -1 ... Note that above notation does not include the pseudo random sequence pn as defined in Section 17.3.5.9 of IEEE Std 802.11a-1999. Allert van Zelst, Airgo Networks

802.11a PER Performance 0.7 dB January 2005 802.11a 24 Mbps mode SISO 48 data subcarriers 4 pilot tones 16-QAM Coding rate ½ Channel Model D 1000 byte packets Without and with TGn impairments Pilot processing: coherent combining Allert van Zelst, Airgo Networks

WWiSE PER Performance January 2005 WWiSE 54 Mbps mode 2  2 MIMO, 20 MHz MMSE detection 54 data subcarriers 2 pilot tones 16-QAM, rate ½ Channel Model D 1000 byte packets Without and with TGn impairments Pilot processing: coherent combining Performance loss compared to ideal sync.: maximal 0.5 dB Allert van Zelst, Airgo Networks

Post-Processing SNR of Pilot Processing January 2005 Post-Processing SNR of Pilot Processing Channel Model D Average SNR per RX antenna = 20 dB Pilot processing: coherent combining Note that the shapes of these curves do not depend on the average SNR per RX antenna Allert van Zelst, Airgo Networks

Post-Processing SNR of Pilot Processing January 2005 Post-Processing SNR of Pilot Processing Channel Model B Average SNR per RX antenna = 20 dB Pilot processing: coherent combining Note that the shapes of these curves do not depend on the average SNR per RX antenna Allert van Zelst, Airgo Networks

January 2005 Conclusions For a 2  2 antenna configuration (which is the minimal requirement to support the mandatory modes of WWiSE (and other proposals)), the WWiSE pilot mapping outperforms the 11a pilot mapping, while having the same tracking bandwidth. If one decides to not fully comply with the mandatory modes by, e.g., designing a 2  1 system, the 11a pilot processing can still be outperformed when the pilot processing for the WWiSE pilot mapping is averaged over two symbols. Allert van Zelst, Airgo Networks

January 2005 References [1] IEEE 802.11/04-0886-06-000n, “WWiSE Proposal: High throughput extension to the 802.11 Standard,” C. Hansen, B. Edwards, et al. Allert van Zelst, Airgo Networks

January 2005 Backup Slides Allert van Zelst, Airgo Networks

Post-Processing SNR of Pilot Processing January 2005 Post-Processing SNR of Pilot Processing Channel Model D Average SNR per RX antenna = 0 dB Pilot processing: coherent combining Allert van Zelst, Airgo Networks