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TGn Sync Complete Proposal

TGn Sync Complete Proposal. Aon Mujtaba, Agere Systems Inc., ( mujtaba@agere.com ) Adrian P Stephens, Intel Corporation, ( adrian.p.stephens@intel.com ) Alek Purkovic, Nortel Networks ( apurkovi@nortelnetworks.com ) Andrew Myles, Cisco Systems ( amyles@cisco.com )

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TGn Sync Complete Proposal

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  1. TGn Sync Complete Proposal Aon Mujtaba, Agere Systems Inc., (mujtaba@agere.com) Adrian P Stephens, Intel Corporation, (adrian.p.stephens@intel.com) Alek Purkovic, Nortel Networks (apurkovi@nortelnetworks.com) Andrew Myles, Cisco Systems (amyles@cisco.com) Brian Johnson, Nortel Networks Corporation, (brjohnso@nortelnetworks.com) Chiu Ngo, Samsung Electronics Co. Ltd., (chiu.ngo@samsung.com) Daisuke Takeda, Toshiba Corporation, (daisuke.takeda@toshiba.co.jp) Darren McNamara, Toshiba Corporation, (Darren.McNamara@toshiba-trel.com) Dongjun (DJ) Lee, Samsung Electronics Co. Ltd., (djthekid.lee@samsung.com) David Bagby, Calypso Consulting, (david.bagby@ieee.org) Eldad Perahia, Cisco Systems, (eperahia@cisco.com) Huanchun Ye, Atheros Communications Inc., (hcye@atheros.com) Hui-Ling Lou, Marvell Semiconductor Inc., (hlou@marvell.com) Isaac Lim Wei Lih, Panasonic (wllim@psl.com.sg) James Chen, Marvell Semiconductor Inc., (jamesc@marvell.com) James Mike Wilson, Intel Corporation, (james.mike.wilson@intel.com) Jan Boer, Agere Systems Inc., (janboer@agere.com) Jari Jokela, Nokia, (jari.jokela@nokia.com) Syed Aon Mujtaba, Agere Systems, et. al.

  2. Authors (continued) Jeff Gilbert, Atheros Communications Inc., (gilbertj@atheros.com) Job Oostveen, Royal Philips Electronics, (job.oostveen@philips.com) Joe Pitarresi, Intel Corporation, (joe.pitarresi@intel.com) Jörg Habetha, Royal Philips Electronics, (joerg.habetha@philips.com) John Sadowsky, Intel Corporation, (john.sadowsky@intel.com) Jon Rosdahl, Samsung Electronics Co. Ltd., (jon.rosdahl@partner.samsung.com) Kiyotaka Kobayashi, Panasonic (kobayashi.kiyotaka@jp.panasonic.com) Luke Qian, Cisco Systems, (lchia@cisco.com) Mary Cramer, Agere Systems (mecramer@agere.com) Masahiro Takagi, Toshiba Corporation, (masahiro3.takagi@toshiba.co.jp) Monisha Ghosh, Royal Philips Electronics, (monisha.ghosh@philips.com) Nico van Waes, Nokia, (nico.vanwaes@nokia.com) Osama Aboul-Magd, Nortel Networks Corporation, (osama@nortelnetworks.com) Paul Feinberg, Sony Electronics Inc., (paul.feinberg@am.sony.com) Pen Li , Royal Philips Electronics (pen.li@philips.com) Peter Loc, Marvell Semiconductor Inc., (ploc@marvell.com) Pieter-Paul Giesberts, Agere Systems Inc., (pgiesberts@agere.com) Richard van Leeuwen, Agere Systems Inc., (rleeuwen@agere.com) Ronald Rietman, Royal Philips Electronics, (ronald.rietman@philips.com) Seigo Nakao, SANYO Electric Co. Ltd., (snakao@gf.hm.rd.sanyo.co.jp) Sheung Li, Atheros Communications Inc., (sheung@atheros.com) Syed Aon Mujtaba, Agere Systems, et. al.

  3. Authors (continued) Stephen Shellhammer, Intel, (stephen.j.shellhammer@intel.com) Taekon Kim, Samsung Electronics Co. Ltd., (taekon.kim@samsung.com) Takashi Fukagawa, Panasonic, (fukagawa.takashi@jp.panasonic.com) Takushi Kunihiro, Sony Corporation, (kuni@wcs.sony.co.jp) Teik-Kheong (TK) Tan, Royal Philips Electronics, (tktan@philips.com) Tomoko Adachi, Toshiba Corporation, (tomo.adachi@toshiba.co.jp) Tomoya Yamaura, Sony Corporation, (yamaura@wcs.sony.co.jp) Tsuguhide Aoki, Toshiba Corporation, (tsuguhide.aoki@toshiba.co.jp) Victor Stolpman, Nokia, (victor.stolpman@nokia.com) Won-Joon Choi, Atheros Communications Inc., (wjchoi@atheros.com) Xiaowen Wang, Agere Systems Inc., (xiaowenw@agere.com) Yasuhiko Tanabe, Toshiba Corporation, (yasuhiko.tanabe@toshiba.co.jp) Yasuhiro Tanaka, SANYO Electric Co. Ltd., (y_tanaka@gf.hm.rd.sanyo.co.jp) Yoshiharu Doi, SANYO Electric Co. Ltd., (doi@gf.hm.rd.sanyo.co.jp) Youngsoo Kim, Samsung Electronics Co. Ltd., (KimYoungsoo@samsung.com) Yuichi Morioka, Sony Corporation, (morioka@wcs.sony.co.jp) Syed Aon Mujtaba, Agere Systems, et. al.

  4. TGn Sync Mission Statement • Develop a scalable architecture to support present and emerging applications • Foster a broad industry representation from vendors and OEMs across market segments Syed Aon Mujtaba, Agere Systems, et. al.

  5. Scalable Architecture across several dimensions Market segments PC Enterprise Consumer Electronics Public Access Handset Perf. over time 315Mbps 630Mbps 140Mbps 10MHz (.11j/p) 20MHz Regulatory Domains 40MHz Syed Aon Mujtaba, Agere Systems, et. al.

  6. … And a well-defined Core Market segments • Mandatory Features: • Two antennas • 20MHz • 140 Mbps Perf . over time Regulatory Domains Syed Aon Mujtaba, Agere Systems, et. al.

  7. Broad Industry Representation PC • OEMs • Cisco • Nokia • Nortel • Panasonic • Sony • Sanyo • Samsung • Toshiba • Semi Vendors • Agere • Atheros • Intel • Marvell • Philips Enterprise Consumer Electronics Asia Pacific / Europe / North America Public Access Handset Semiconductor Syed Aon Mujtaba, Agere Systems, et. al.

  8. PHY Summary of TGnSync Proposal • Mandatory Features: • 2 Spatial Streams • 20MHz and 40MHz* channelization • 1/2, 2/3, 3/4, and 7/8 channel coding rates • 400ns & 800ns Guard Interval • Full & seamless interoperability with a/b/g • Optional Features: • Transmit Beamforming • Low Density Parity Check (LDPC) Coding • 3 or 4 spatial streams 140Mbps in 20MHz 243Mbps in 40MHz *Not required in regulatory domains where prohibited. Syed Aon Mujtaba, Agere Systems, et. al.

  9. MAC Summary of TGn Sync Proposal • Mandatory Features: • MAC Level Frame Aggregation • Link Adaptation • Legacy Compatible Protection • QoS Support (802.11e) • Multi-Destination Aggregation • MAC Header Compression • Block ACK Compression • 20/40 MHz Channel management ** • Optional Features: • Bi-directional data flow • Power management for MIMO receivers Optional at Transmitter Mandatory at Receiver ** Depends on local regulation Syed Aon Mujtaba, Agere Systems, et. al.

  10. PHY Syed Aon Mujtaba, Agere Systems, et. al.

  11. PHY Architectural Features • Mandatory throughput enhancement: • Spatial division multiplexing (SDM) of 2 Spatial Streams • Bandwidth expansion  interoperable 20MHz and 40MHz* • Increased channel coding rate (i.e. 7/8) • Shortened guard interval (i.e. 400ns) • Optional robustness & throughput enhancement: • Transmit beamforming • Advanced coding (LDPC) • SDM with 3 or 4 spatial streams Max Mandatory rate in 20MHz = 140 Mbps Max Mandatory rate in 40MHz = 243 Mbps (with 2x2 architecture using 2 spatial streams) with the option to scale to 630Mbps * Not required in regulatory domains where prohibited Syed Aon Mujtaba, Agere Systems, et. al.

  12. Scalable PHY Architecture Mandatory Optional Robustness Enhancement Closed Loop TX BF Open Loop SDM Robustness Enhancement LDPC Conv. Coding Rate Feedback Throughput Enhancement 2 Spatial Streams 4 Spatial Streams Regulatory Constraints Low Cost & Robust 20 MHz 40 MHz  140 Mbps 630 Mbps 243 Mbps Syed Aon Mujtaba, Agere Systems, et. al.

  13. 40MHz Mandatory Where Possible • Situation • 40MHz solution offers high throughput and robustness with the fewest antennas • Complication • Some major world markets are currently restricted to 20MHz channel bandwidth • Market confusion & reduced network efficiency if HT devices are both 20-HT-only and 20/40-HT • Industry leadership opportunity • Make 40MHz HT product mandatory where possible, with 20MHz interoperability • All 20MHz-only product fully compatible with 20/40MHz product Syed Aon Mujtaba, Agere Systems, et. al.

  14. Mapping Spatial Streams to Multiple Antennas • Number of spatial streams = Number of TX antennas • 1 spatial stream mapped to 1 antenna • Spatial division multiplexing • Equal rates on all spatial streams • Number of spatial streams ≤ Number of TX antennas • Each spatial stream mapped to all transmit antennas • Optional orthogonal spatial spreading • Exploits all transmit antennas • No channel state info at TX required • Optional transmit beamforming • Focusing the energy in a desired direction • Requires channel state info at TX • Supports unequal rates on different spatial streams • With per spatial stream training, no change needed at the RX Syed Aon Mujtaba, Agere Systems, et. al.

  15. TX Arch: Spatial Division Multiplexinge.g.2 Spatial streams with 2 TX antennas (mandatory) iFFT Modulator Preamble insert GI window symbols Pilots Frequency Interleaver Constellation Mapper Scrambled MPDU iFFT Modulator Preamble Channel Encoder Puncturer Spatial parser insert GI window symbols Pilots Frequency Interleaver Constellation Mapper Syed Aon Mujtaba, Agere Systems, et. al.

  16. Tone Design for 20 and 40 MHz • 20 MHz: • Identical to 802.11a • 64 point FFT • 48 data tones • 4 pilot tones -26 -21 -7 -1 +1 +7 +21 +26 Tone Fill in the Guard Band • 40 MHz: • 128 point FFT • 108 data tones • 6 pilot tones -25 -11 +11 +25 +53 -53 +32 -2 +2 -64 -58 -32 -6 +6 +58 +63 Legacy 20 MHz in Lower Sub-Channel Legacy 20 MHz in Upper Sub-Channel Syed Aon Mujtaba, Agere Systems, et. al.

  17. 2x2-40 MHz 4x4-20 MHz 2x3-20 MHz w/ short GI 2x2-20 MHz w/ short GI Motivation for 40MHz Channelization • 2x2 – 40 MHz • Only 2 RF chains => Cost effective & low power • Lower SNR at same throughput => Enhanced robustness 260 240 220 200 Sweet spot for 100Mbps top-of-MAC 180 160 140 Over the Air Throughput (Mbps) 120 100 80 Basic MIMO MCS set No impairments 1000 byte packets TGn channel model B 60 40 20 0 0 5 10 15 20 25 30 35 SNR (dB) Syed Aon Mujtaba, Agere Systems, et. al.

  18. Scalable Basic MCS Set Mandatory MCS ‡ Duplicate format, BPSK R = ½ provides 6 Mbps for 40 MHz channels Optional MCS Syed Aon Mujtaba, Agere Systems, et. al.

  19. HT-PPDU Format in 20MHz HT STF HT LTF-1 HT LTF-2 L-STF L-LTF L-SIG HT-SIG HT-DATA ANT_1 20MHz L-STF L-LTF L-SIG HT-SIG HT-DATA ANT_2 20MHz Legacy Compatible Preamble HT-specific Preamble Legend L- Legacy HT- High Throughput STF Short Training Field LTF Long Training Field SIG Signal Field Legacy Compatible Can be decoded by anylegacy 802.11a or g compliant device for interoperability Syed Aon Mujtaba, Agere Systems, et. al.

  20. L-STF L-LTF L-SIG HT-SIG HT-DATA Duplicate L-STF Duplicate L-LTF Dup. L-SIG Duplicate HT-SIG HT-PPDU Format in 40MHz ANT_1 40MHz HT STF HT LTF-1 HT LTF-2 L-STF L-LTF L-SIG HT-SIG HT-DATA ANT_2 40MHz Duplicate L-STF Duplicate L-LTF Dup. L-SIG Duplicate HT-SIG Legacy Compatible Preamble HT-specific Preamble Syed Aon Mujtaba, Agere Systems, et. al.

  21. Spoofing • Spoofing is the use of the legacy RATE and LENGTH fields to keep the legacy STA off the air for a desired period of time • The duration indicated in the L-SIG can exceed the actual duration in the HT-SIG  MAC uses this as a protection mechanism • For a HT-PPDU, L-SIG RATE is hard-coded at 6 Mbps • max MSDU length = 2304 Bytes spoofing duration up to ~3 msec Syed Aon Mujtaba, Agere Systems, et. al.

  22. HT PPDU Detection L-STF L-LTF L-SIG HT-SIG • Auto-detection scheme on HT-SIG • Q-BPSK modulation (BPSK w/ 90-deg rotation) • Invert the polarity of the pilot tones • Combined methods provide speed and reliability • L-SIG reserved bit is not used • Legacy devices are using the “reserved bit” in undefined ways or Legacy DATA L-STF L-LTF L-SIG Legacy Compatible Preamble Syed Aon Mujtaba, Agere Systems, et. al.

  23. HT-SIG Contents HT-SIG1 MCS (6 bits) MCS (6 bits) HTLENGTH (18 bits) HTLENGTH (18 bits) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 SOUNDING PACKET (1 bit) RESERVED (1 bit) ADV CODING (1 bit) NUMBER HT-LTF (2 bits) 20/40 BW (1 bit) SCRAMBLER INIT (2 bits) HT-SIG2 SHORT GI (1 bit) AGGRAGATE (1 bit) CRC (8 bits) SIGNAL TAIL (6 bits) SIGNAL TAIL (6 bits) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Transmit Order Syed Aon Mujtaba, Agere Systems, et. al.

  24. For MIMO, accurate AGC requires power estimates from each TX antenna to each RX antenna If L-STF is used for MIMO AGC, require orthogonalization of L-STF across multiple TX antennas Perfect orthogonality is achieved with tone interleaving However, tone interleaving is incompatible with legacy receivers using cross correlation on the L-STF Cyclic delay may be used to separate transmission paths, but the delay has to be limited to preserve the cross correlation property of the L-STF However, limited cyclic delay results in AGC inaccuracy, as shown on the next slide MIMO AGC multiple spatial streams single spatial stream L-STF L-LTF L-SIG HT-SIG HT-DATA AGC measured AGC locked Syed Aon Mujtaba, Agere Systems, et. al.

  25. Power Fluctuation with Cyclic Delay on the L-STF Data power 1 Power fluctuation with tone interleaving is within 1dB of the data power 0.9 STF = Tone Interleaved STF = Cyclic Delay 0.8 2x2, TGn Channel D SNR = 30dB 0.7 0.6 CDF(x) 0.5 Introduce a dedicated STF for MIMO that is tone interleaved Reduces 1 bit in the ADC  cost & power savings 0.4 0.3 0.2 0.1 0 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 x = Power fluctuation of AGC setting w.r.t. data power (dB) Syed Aon Mujtaba, Agere Systems, et. al.

  26. Power Fluctuation of HT-LTF w.r.t. Data Data power 1 0.9 HT-LTF = Tone Interleaved 0.8 HT-LTF = Walsh + Cyclic Delay Large deviation of HT-LTF power wrt data power will result in higher channel estimation error 0.7 2x2, TGn Channel D SNR = 30dB 0.6 CDF(x) 0.5 0.4 0.3 0.2 HT-LTF should be tone interleaved 0.1 0 -10 -8 -6 -4 -2 0 2 4 x = Power fluctuation of HT-LTF w.r.t. data (dB) Syed Aon Mujtaba, Agere Systems, et. al.

  27. Tone Interleaved HT Training Fields • HT-STF • 2nd AGC measurement is used to fine-tune MIMO reception • HT-LTF • Used for MIMO channel estimation • Additional frequency or time alignment Syed Aon Mujtaba, Agere Systems, et. al.

  28. Spatial Stream Tone Interleaving • Color indicates spatial stream • Each HT-LTF has equal representation from all spatial streams • Eliminates avg. power fluctuation across LTFs • HT-LTS symbols are designed to minimize PAPR • Distinct symbol designs for different number of spatial streams Syed Aon Mujtaba, Agere Systems, et. al.

  29. Summary of HT-LTF • Robust design • Tone interleaving reduces power fluctuation • 2 symbols per field • 3dB of channel estimation gain with baseline per-tone estimation • Enables additional frequency offset estimation • Per spatial stream training • HT-LTF and HT-Data undergo same spatial transformation • Number of HT-LTFs = Number of spatial streams Syed Aon Mujtaba, Agere Systems, et. al.

  30. 20/40 MHz BSS Operation • A 20/40 MHz BSS supports interoperability among any combination of: • 20/40 MHz HT clients • 20 MHz HT client • 20 MHz legacy client • Not required in regulatory domains where prohibited Syed Aon Mujtaba, Agere Systems, et. al.

  31. 20/40 MHz Interoperability • 40 MHz PPDU into a 40 MHz receiver • Get 3dB processing gain – duplicate format allows combining the legacy compatible preamble and the HT-SIG in an MRC fashion • 20 MHz PPDU into a 40 MHz receiver • The active 20 MHz sub-channel is detected using energy measurement of the two sub-channels • Inactive tones at the FFT output (i.e. 64 out of 128) are not used • 40 MHz PPDU into a20 MHz receiver • One 20 MHz sub-channel is sufficient to decode the L-SIG and the HT-SIG • See MAC slides for additional information on 20/40 inter-op Syed Aon Mujtaba, Agere Systems, et. al.

  32. TX Arch: Basic TX Beamforming or Spatial Spreadinge.g.2 Spatial Streams with 3 TX Antennas (optional) Per Spatial Stream Processing: HT-LTF & HT-Data undergo same spatial transformation HT LTF iFFT Mod. insert GI window Pilots Frequency Interleaver Constellation Mapper Spatial Steering (TX Beamforming), or Orthogonal Spatial Spreading with Cyclical Delay iFFT Mod. insert GI window HT LTF Scrambled MPDU Channel Encoder Puncturer Spatial Parser Pilots iFFT Mod. insert GI Frequency Interleaver Constellation Mapper window Syed Aon Mujtaba, Agere Systems, et. al.

  33. SNR Gain with TX Beamforming 1000 byte packets No impairment 20MHz, channel D 4 TX-antenna AP  2 RX-antenna client ~10 dB gain of 4x2-ABF over 2x2-SDM => cost effective client Syed Aon Mujtaba, Agere Systems, et. al.

  34. Optional Advanced Coding • Low Density Parity Check (LDPC) • Capacity approaching FEC • Iterative decoding  superior performance • Strong performance in AWGN and fading channels • Typically 2-4 dB improvement over convolutional codes, depending on channel conditions • Code structure enables low complexity architectures • Layered belief propagation reduces memory requirements and improves convergence performance Syed Aon Mujtaba, Agere Systems, et. al.

  35. LDPC Performance Comparison 3.5 dB of coding gain Syed Aon Mujtaba, Agere Systems, et. al.

  36. PHY Summary • Mandatory Rate of 140Mbps in 20MHz: • 2 Spatial Streams • 7/8th rate coding • 400ns Guard Interval • Low Cost & Robust Throughput Enhancement: • Scalable to 243 Mbps in 40MHz • Optional Robustness/Throughput Enhancements: • LDPC Coding • Transmit Beamforming • Scalable to 630Mbps with 4 spatial streams in 40MHz Syed Aon Mujtaba, Agere Systems, et. al.

  37. MAC Syed Aon Mujtaba, Agere Systems, et. al.

  38. MAC Challenges in HT Environment • HT requires an improvement in MAC Efficiency • HT requires effective Rate Adaptation • HT requires Legacy Protection Syed Aon Mujtaba, Agere Systems, et. al.

  39. HT MAC Features • Aggregation Structure • Header Compression • Aggregation Exchanges • Protocol for link adaptation • Protocol for reverse direction data • Single and multiple responder • Protection Mechanisms • Coexistence & Channel Management • MIMO Power Management • Block Ack Enhancements Syed Aon Mujtaba, Agere Systems, et. al.

  40. Scalable MAC Architecture • LEGACY INTEROP. • Long NAV • Pairwise Spoofing • Single-Ended Spoofing Robust & Scalable MAC Architecture • ADDITIONAL EFFICIENCY • Header Compression • Multi-Receiver Aggregation • Bi-Directional Data Flow • BA Enhancements • BASELINE MAC • Robust Aggregation • QoS Support (802.11e) • CHANNEL MANAGEMENT • 20/40 MHz Modes Syed Aon Mujtaba, Agere Systems, et. al.

  41. Robust Structure Aggregation is a purely-MAC function PHY has no knowledge of MPDU boundaries Simplest MAC-PHY interface Control and data MPDUs can be aggregated Aggregation Structure Syed Aon Mujtaba, Agere Systems, et. al.

  42. MAC Header Compression • MHDR MPDU carries repeated Header fields • CHDATA MPDU refers to previous MHDR MPDU • HID field ties the two together • Context only within current aggregate Syed Aon Mujtaba, Agere Systems, et. al.

  43. Aggregate Exchange Sequences • Aggregate exchange sequences include single frames or groups of frames that are exchanged “at the same time” • Allows effective use of Aggregate Feature • Allows control and data to be sent in the same PPDU • An initiator sends a PPDU and a responder may transmit a response PPDU • Either PPDU can be an aggregate (“Initiator” / “responder” are new terms relating to roles in aggregate exchange protocol) Syed Aon Mujtaba, Agere Systems, et. al.

  44. Basic Aggregate Exchange Syed Aon Mujtaba, Agere Systems, et. al.

  45. Reverse Direction Data Flow • Gives an opportunity for a responder to transmit data to an initiator during the initiator’s TXOP • Aggregates data with response control MPDUs • Reduces Contention • Effective in increasing TCP/IP performance Syed Aon Mujtaba, Agere Systems, et. al.

  46. Reverse Direction Protocol Syed Aon Mujtaba, Agere Systems, et. al.

  47. Link Adaptation Protocol • Support for PHY closed-loop modes with on-the-air signalling • Request for training and feedback are carried in control frames • Rate feedback supported • Transmit beamforming training supported • sounding packet • calibration exchange • Timing of response is not constrained permitting a wide range of implementation options Syed Aon Mujtaba, Agere Systems, et. al.

  48. Link Adaptation Protocol Syed Aon Mujtaba, Agere Systems, et. al.

  49. Multiple Receiver Aggregation • Aggregates can contain MPDUs addressed for multiple receiver addresses (MRA) • MRA may be followed by multiple responses from the multiple receivers • MRA is effective in improving throughput in applications where frames are buffered to many receiver addresses Syed Aon Mujtaba, Agere Systems, et. al.

  50. Periodic Multi-Receiver Aggregation Syed Aon Mujtaba, Agere Systems, et. al.

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