Joint Proposal PHY Overview November 2005 doc.: IEEE 802.11-05/xxxr0 November 2005 Joint Proposal PHY Overview Date: 2005-11-15 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>. Mujtaba (Agere), Petranovich (Conexant) et. al. Mujtaba (Agere), Petranovich (Conexant), Fischer (Broadcom), Stephens (Intel) et. al.

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November 2005 Abstract This document provides an overview of the joint proposal PHY, which is under development by the Joint Proposal group of TGn Sync, WWiSE, and Mitmot. Mujtaba (Agere), Petranovich (Conexant) et. al.

November 2005 PHY Overview Mujtaba (Agere), Petranovich (Conexant) et. al.

JP “decision making pipeline” November 2005 JP “decision making pipeline” Item under discussion “Item agreed upon” Motion passes Motion: Draft text put up for ballot Item brought forth for consideration Presentations, discussions, & strawpolls Draft text included in JP spec Motion fails (i.e. less than 75% support) Mujtaba (Agere), Petranovich (Conexant) et. al.

Recap of Architecture Encoder Puncturer Parser Interleaver QAM Mapper November 2005 Recap of Architecture Encoder Puncturer Parser Interleaver QAM Mapper Antenna Mapper iFFT Window & GI RF Pilot Preamble Agreed upon Under discussion Mujtaba (Agere), Petranovich (Conexant) et. al.

Scalable PHY Architecture November 2005 Scalable PHY Architecture Mandatory Optional Robustness Enhancement Open Loop SDM Closed Loop Tx BF Robustness Enhancement Conv. Coding LDPC RX Assisted Rate Control Throughput Enhancement 2 Spatial Streams 4 Spatial Streams Throughput Enhancement 20 MHz 40 MHz 150 Mbps  600 Mbps Mujtaba (Agere), Petranovich (Conexant) et. al.

JP PHY Key Parameters November 2005 Parameter JP PHY Spatial Streams 1 to 4 FEC (BCC) R=1/2, K=7 Generator polynomial (1338, 1718) Puncturer: 2/3, 3/4, and 5/6 Number of Encoders TBD (1 or 2) Parser TBD (Group parser or Bit Parser or Hybrid) Interleaver Block based One for each spatial stream Spatial streams separated by frequency rotation QAM Modes BPSK, QPSK, 16-QAM, 64-QAM 256-QAM TBD Antenna mapper STBC, beam steering TBD iFFT 20 MHz: 56 tones (52 data tones + 4 pilots) 40 MHz: 114 tones (108 data tones + 6 pilots) Mujtaba (Agere), Petranovich (Conexant) et. al.

JP PHY Key Parameters November 2005 Parameter JP PHY GI 800ns 400ns TBD Signal Bandwidth 20MHz, 40 MHz Long MIMO Preamble Long mixed mode preamble Legacy compatibility: 100% interoperable Supports per tone channel estimation Supports frequency smoothing & interpolation Compatible with beam forming Short MIMO Preamble TBD (green field or mixed mode) HT-SIG modulation TBD Scrambler Init MCS Set Symmetric MCS sets: defined from BPSK to 64-QAM Asymmetric MCS sets (primarily for beam forming) Mujtaba (Agere), Petranovich (Conexant) et. al.

JP PHY Key Parameters November 2005 Parameter JP PHY Pilot Tones 20 MHz 4 pilot tones 40 MHz 6 pilot tones Advanced Codec Low Density Parity Check codes are currently being developed Code structure has been defined Specific codes currently being verified Final selection expected this week Sounding Packet Format Format is TBD (staggered sounding or block structure) Space-Time Block Codes Codes defined: 2 x 1 3 x 2 4 x 2 4 x 3 Optional or mandatory TBD Mujtaba (Agere), Petranovich (Conexant) et. al.

Long Mixed Mode Preamble November 2005 Long Mixed Mode Preamble Structure Legacy portion maximum CDD delay ≤ 200 nsec for reliable legacy interoperability High throughput CDD delay at least 200 nsec per antenna for improved performance Mujtaba (Agere), Petranovich (Conexant) et. al.

Items currently under discussion November 2005 Items currently under discussion Number of encoders Parser format 256 QAM Beam steering 400ns GI Short preamble Asymmetric MCS Mujtaba (Agere), Petranovich (Conexant) et. al.

Number of encoders Single encoder: Dual encoder: November 2005 Number of encoders Single encoder: Lower implementation overhead Difficult implementation at very high data rates Dual encoder: Perhaps higher implementation overhead Not attractive for LDPC encoding Alleviates implementation concerns at very high data rates Under what conditions should the second encoder kick in? Mujtaba (Agere), Petranovich (Conexant) et. al.

Parser format Two flavors: Bit wise: Group wise: Hybrid: Bit wise November 2005 Parser format Two flavors: Bit wise Group wise Bit wise: Better performance for symmetric modulations However, does not support asymmetric modulations Group wise: Designed to support asymmetric modulations However, performance slightly degraded for symmetric modulations Hybrid: Bit wise for symmetric & group wise for asymmetric Complicates control? Mujtaba (Agere), Petranovich (Conexant) et. al.

256-QAM Requires very high EVM at Tx Requires very high SNR at Rx November 2005 256-QAM Requires very high EVM at Tx Requires very high SNR at Rx “Perhaps” feasible if system has adequate array and/or diversity gain: For example, when used with beam steering Mujtaba (Agere), Petranovich (Conexant) et. al.

Beam steering Format of sounding packet: November 2005 Beam steering Format of sounding packet: Two flavors – staggered or block Staggered – introduces a new preamble format, but preserves performance Block – reuses the existing preamble format, but may experience power fluctuation Feedback of channel estimates to the Tx: Explicit Implicit Mujtaba (Agere), Petranovich (Conexant) et. al.

400ns GI 400ns GI improves efficiency by reducing overhead November 2005 400ns GI 400ns GI improves efficiency by reducing overhead Useful for scenarios that are limited in delay spread However, 400ns GI complicates the design of the channel select filter at the receiver Reducing the temporal footprint of the filter may compromise it’s ability to reject adjacent channel energy Frequency with which delay spread needs to be estimated is unclear Mujtaba (Agere), Petranovich (Conexant) et. al.

Short Preamble Two flavors: Greenfield: Greenfield format November 2005 Short Preamble Two flavors: Greenfield format Short mixed mode preamble Greenfield: Shortest possible preamble No legacy interoperability Legacy interoperable Shorter than the “Long Mixed Mode” preamble Design is more difficult to optimize since constraints are higher Mujtaba (Agere), Petranovich (Conexant) et. al.

November 2005 Asymmetric MCS Increases “link rate” when eigen-channels are highly asymmetric in SNR Can only be used if channel state information is available at the transmitter However, increases system complexity, size of the MCS set, and burdens interoperability testing Mujtaba (Agere), Petranovich (Conexant) et. al.

November 2005 Summary Open items have pros and cons that place them in the “gray” area Not a black and white decision! Consensus will be reached via compromise rather than based on definitive technical data Mujtaba (Agere), Petranovich (Conexant) et. al.