November 2004 doc IEEE 802 11 04888 r
November 2004 doc. : IEEE 802. 11 -04/888 r 3 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 Mc. Namara, Toshiba Corporation, (Darren. Mc. Namara@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) Submission 1 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 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, (masahiro 3. 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) Submission 2 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 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. , (Kim. Youngsoo@samsung. com) Yuichi Morioka, Sony Corporation, (morioka@wcs. sony. co. jp) Submission 3 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 TGn Sync Mission Statement Æ Develop a scalable architecture to support present and emerging applications Æ Foster a broad industry representation from vendors and OEMs across market segments Submission 4 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Scalable Architecture across several dimensions Market segments PC Enterprise Consumer Electronics Public Access Handset 140 Mbps 10 MHz (. 11 j/p) 315 Mbps 630 Mbps Perf. over time 20 MHz Regulatory Domains Submission 40 MHz 5 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 … And a well-defined Core Market segments Mandatory Features: - Two antennas - 20 MHz - 140 Mbps Perf. over time Regulatory Domains Submission 6 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Asia Pacific / Europe / North America Broad Industry Representation Submission Æ OEMs ■ ■ ■ ■ Æ Cisco Nokia Nortel Panasonic Sony Sanyo Samsung Toshiba Semi Vendors ■ ■ ■ Agere Atheros Intel Marvell Philips PC Enterprise Consumer Electronics Public Access Handset Semiconductor 7 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 PHY Summary of TGn. Sync Proposal Æ Mandatory Features: ■ ■ ■ Æ 2 Spatial Streams 20 MHz and 40 MHz* channelization 1/2, 2/3, 3/4, and 7/8 channel coding rates 400 ns & 800 ns Guard Interval Full & seamless interoperability with a/b/g 140 Mbps in 20 MHz 243 Mbps in 40 MHz Optional Features: ■ ■ ■ Transmit Beamforming Low Density Parity Check (LDPC) Coding 3 or 4 spatial streams *Not required in regulatory domains where prohibited. Submission 8 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 MAC Summary of TGn Sync Proposal Æ Mandatory Features: ■ MAC Level Frame Aggregation ■ Link Adaptation ■ Legacy Compatible Protection ■ Qo. S Support (802. 11 e) ■ Multi-Destination Aggregation Optional at Transmitter Mandatory at Receiver ■ MAC Header Compression ■ Block ACK Compression ■ 20/40 MHz Channel management ** ** Depends on Æ Optional Features: ■ Bi-directional data flow ■ Power management for MIMO receivers Submission 9 local regulation Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 PHY Submission 10 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 PHY Architectural Features Æ Mandatory throughput enhancement: ■ ■ Spatial division multiplexing (SDM) of 2 Spatial Streams Bandwidth expansion interoperable 20 MHz and 40 MHz* Increased channel coding rate (i. e. 7/8) Shortened guard interval (i. e. 400 ns) Max Mandatory rate in 20 MHz = 140 Mbps Max Mandatory rate in 40 MHz = 243 Mbps (with 2 x 2 architecture using 2 spatial streams) Æ Optional robustness & throughput enhancement: ■ ■ ■ Transmit beamforming Advanced coding (LDPC) SDM with 3 or 4 spatial streams with the option to scale to 630 Mbps * Not required in regulatory domains where prohibited Submission 11 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Scalable PHY Architecture Mandatory Open Loop SDM Conv. Coding Rate Feedback 2 Spatial Streams Regulatory Constraints Low Cost & Robust 20 MHz 40 MHz 140 Mbps 243 Mbps Submission Robustness Enhancement Throughput Enhancement Optional Closed Loop TX BF LDPC 4 Spatial Streams 630 Mbps 12 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 40 MHz Mandatory Where Possible Æ Situation ■ Æ Complication ■ ■ Æ 40 MHz solution offers high throughput and robustness with the fewest antennas Some major world markets are currently restricted to 20 MHz channel bandwidth Market confusion & reduced network efficiency if HT devices are both 20 -HT-only and 20/40 -HT Industry leadership opportunity ■ ■ Submission Make 40 MHz HT product mandatory where possible, with 20 MHz interoperability All 20 MHz-only product fully compatible with 20/40 MHz product 13 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Mapping Spatial Streams to Multiple Antennas Æ Number of spatial streams = Number of TX antennas ■ ■ ■ Æ 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 ■ Submission With per spatial stream training, no change needed at the RX 14 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 TX Arch: Spatial Division Multiplexing e. g. 2 Spatial streams with 2 TX antennas (mandatory) Preamble Pilots Spatial parser Puncturer Channel Encoder Scrambled MPDU Frequency Interleaver insert GI window symbols Constellation Mapper Preamble Pilots Frequency Interleaver Submission i. FFT Modulator Constellation Mapper 15 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Tone Design for 20 and 40 MHz 20 MHz: • • Identical to 802. 11 a 64 point FFT 48 data tones -26 4 pilot tones -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 -53 -64 -58 -11 -32 -6 Legacy 20 MHz in Lower Sub-Channel Submission +11 -2 +2 +6 +25 +53 +32 +58 +63 Legacy 20 MHz in Upper Sub-Channel 16 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Motivation for 40 MHz Channelization 2 x 2 – 40 MHz • Only 2 RF chains => Cost effective & low power • Lower SNR at same throughput => Enhanced robustness 260 240 220 Over the Air Throughput (Mbps) 200 180 2 x 2 -40 MHz 160 4 x 4 -20 MHz Sweet spot for 100 Mbps top-of-MAC 2 x 3 -20 MHz w/ short GI 140 2 x 2 -20 MHz w/ short GI 120 100 80 60 Basic MIMO MCS set No impairments 1000 byte packets TGn channel model B 40 20 0 0 5 10 15 20 25 30 35 SNR (d. B) Submission 17 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Scalable Basic MCS Set Modulation Code Rate Data Rates 20 MHz (Mbps) (1, 2, 3, 4 spatial streams) Data Rates 40 MHz (Mbps) (1, 2, 3, 4 spatial streams) BPSK 1/2 6, 12, 18, 24 6‡, 13. 5, 27, 45. 5, 54 QPSK 1/2 12, 24, 36, 48 27, 54, 81, 108 QPSK 3/4 18, 35, 54, 72 40. 5, 81, 121. 5, 162 16 QAM 1/2 24, 48, 72, 96 54, 108, 162, 216 16 QAM 3/4 36, 72, 108, 144 81, 162, 243, 324 64 QAM 2/3 48, 96, 144, 192 108, 216, 324, 432 64 QAM 3/4 54, 108, 162, 216 121. 5, 243, 364. 5, 486 64 QAM 7/8 63, 126, 189, 252 141. 7, 283. 5, 425. 2, 567 64 QAM 7/8 with ½ GI 70, 140, 210, 280 157. 5, 315, 472. 5, 630 Mandatory MCS ‡ Duplicate format, BPSK R = ½ provides 6 Mbps for 40 MHz channels Submission 18 Optional MCS Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 HT-PPDU Format in 20 MHz HT LTF-2 20 MHz HT LTF-1 L-STF L-LTF L-SIG HT-DATA 20 MHz ANT_2 ANT_1 HT STF L-LTF L-SIG HT-DATA Legacy Compatible Preamble Legend LHTSTF LTF SIG Submission HT-specific Preamble Legacy Compatible Can be decoded by any legacy 802. 11 a or g compliant device for interoperability Legacy High Throughput Short Training Field Long Training Field Signal Field 19 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 40 MHz ANT_1 HT-PPDU Format in 40 MHz L-STF L-LTF L-SIG HT-DATA Duplicate Duplicate L-STF L-LTF L-SIG HT-SIG 40 MHz ANT_2 HT STF L-LTF L-SIG HT LTF-1 HT LTF-2 HT-SIG HT-DATA Duplicate Duplicate L-STF L-LTF L-SIG HT-SIG Legacy Compatible Preamble Submission HT-specific Preamble 20 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Spoofing Æ 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 Æ The duration indicated in the L-SIG can exceed the actual duration in the HT-SIG MAC uses this as a protection mechanism Æ For a HT-PPDU, L-SIG RATE is hard-coded at 6 Mbps ■ Submission max MSDU length = 2304 Bytes spoofing duration up to ~3 msec 21 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 HT PPDU Detection L-STF L-LTF L-SIG HT-SIG or L-STF L-LTF Legacy DATA L-SIG Legacy Compatible Preamble Æ Auto-detection scheme on HT-SIG ■ ■ ■ Æ 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 ■ Submission Legacy devices are using the “reserved bit” in undefined ways 22 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 HT-SIG Contents HT-SIG 1 MCS (6 bits) 2 3 4 5 6 7 8 7 9 10 11 12 13 14 15 16 20/40 BW (1 bit) SOUNDING PACKET (1 bit) 1 4 SCRAMBLER INIT (2 bits) RESERVED (1 bit) 0 3 AGGRAGATE (1 bit) 2 SHORT GI (1 bit) 1 NUMBER HT-LTF (2 bits) 0 ADV CODING (1 bit) HTLENGTH (18 bits) 8 9 17 18 19 20 21 22 23 HT-SIG 2 CRC (8 bits) 10 11 12 13 14 15 16 SIGNAL TAIL (6 bits) 17 18 19 20 21 22 23 Transmit Order Submission 23 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 MIMO AGC multiple spatial streams single spatial stream L-STF AGC measured Æ Æ Æ L-SIG HT-DATA AGC locked 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 ■ Æ L-LTF 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 Submission 24 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Power Fluctuation with Cyclic Delay on the L-STF Data power 1 0. 9 STF = Tone Interleaved STF = Cyclic Delay 0. 8 2 x 2, TGn Channel D SNR = 30 d. B 0. 7 CDF(x) Power fluctuation with tone interleaving is within 1 d. B of the data power 0. 6 0. 5 Introduce a dedicated STF for MIMO that is tone interleaved 0. 4 0. 3 0. 2 0. 1 0 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 Reduces 1 bit in the ADC cost & power savings x = Power fluctuation of AGC setting w. r. t. data power (d. B) Submission 25 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Power Fluctuation of HT-LTF w. r. t. Data power 1 0. 9 HT-LTF = Tone Interleaved 0. 8 HT-LTF = Walsh + Cyclic Delay CDF(x) 0. 7 Large deviation of HT-LTF power wrt data power will result in higher channel estimation error 2 x 2, TGn Channel D SNR = 30 d. B 0. 6 0. 5 0. 4 0. 3 0. 2 HT-LTF should be tone interleaved 0. 1 0 -10 Submission -8 -6 -4 -2 0 2 x = Power fluctuation of HT-LTF w. r. t. data (d. B) 26 4 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Tone Interleaved HT Training Fields Æ HT-STF ■ Æ 2 nd AGC measurement is used to fine-tune MIMO reception HT-LTF ■ ■ Submission Used for MIMO channel estimation Additional frequency or time alignment 27 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 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 Submission 28 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Summary of HT-LTF Æ Robust design ■ ■ Tone interleaving reduces power fluctuation 2 symbols per field • 3 d. B of channel estimation gain with baseline per-tone estimation • Enables additional frequency offset estimation Æ Per spatial stream training ■ ■ HT-LTF and HT-Data undergo same spatial transformation Number of HT-LTFs = Number of spatial streams Submission 29 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 20/40 MHz BSS Operation ÆA 20/40 MHz BSS supports interoperability among any combination of: ■ ■ ■ 20/40 MHz HT clients 20 MHz HT client 20 MHz legacy client Æ Not required in regulatory domains where prohibited Submission 30 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 20/40 MHz Interoperability Æ 40 MHz PPDU into a 40 MHz receiver ■ Æ 20 MHz PPDU into a 40 MHz receiver ■ ■ Æ 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 a 20 MHz receiver ■ Æ Get 3 d. B processing gain – duplicate format allows combining the legacy compatible preamble and the HT-SIG in an MRC fashion 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 Submission 31 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 TX Arch: Basic TX Beamforming or Spatial Spreading e. g. 2 Spatial Streams with 3 TX Antennas (optional) HT LTF Pilots Frequency Interleaver Submission Constellation Mapper 32 window Spatial Parser Puncturer Channel Encoder Scrambled MPDU Frequency Interleaver insert GI i. FFT Mod. insert GI window Pilots i. FFT Mod. insert GI window HT LTF Spatial Steering (TX Beamforming), or Orthogonal Spatial Spreading with Cyclical Delay Per Spatial Stream Processing: HT-LTF & HT-Data undergo same spatial transformation Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 SNR Gain with TX Beamforming 1000 byte packets No impairment 20 MHz, channel D 4 TX-antenna AP 2 RX-antenna clie ~10 d. B gain of 4 x 2 -ABF over 2 x 2 -SDM => cost effective client Submission 33 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Optional Advanced Coding Æ Low Density Parity Check (LDPC) ■ ■ Æ Strong performance in AWGN and fading channels ■ Æ Capacity approaching FEC Iterative decoding superior performance Typically 2 -4 d. B improvement over convolutional codes, depending on channel conditions Code structure enables low complexity architectures ■ Layered belief propagation reduces memory requirements and improves convergence performance Submission 34 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 LDPC Performance Comparison 3. 5 d. B of coding gain Submission 35 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 PHY Summary Æ Mandatory Rate of 140 Mbps in 20 MHz: ■ ■ ■ Æ Low Cost & Robust Throughput Enhancement: ■ Æ 2 Spatial Streams 7/8 th rate coding 400 ns Guard Interval Scalable to 243 Mbps in 40 MHz Optional Robustness/Throughput Enhancements: ■ ■ ■ Submission LDPC Coding Transmit Beamforming Scalable to 630 Mbps with 4 spatial streams in 40 MHz 36 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 MAC Submission 37 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 MAC Challenges in HT Environment Æ Æ Æ HT requires an improvement in MAC Efficiency HT requires effective Rate Adaptation HT requires Legacy Protection Submission 38 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 HT MAC Features Æ Æ Æ Aggregation Structure Header Compression Aggregation Exchanges ■ ■ ■ Æ Æ Protocol for link adaptation Protocol for reverse direction data Single and multiple responder Protection Mechanisms Coexistence & Channel Management MIMO Power Management Block Ack Enhancements Submission 39 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Scalable MAC Architecture LEGACY INTEROP. • Long NAV • Pairwise Spoofing • Single-Ended Spoofing BASELINE MAC • Robust Aggregation • Qo. S Support (802. 11 e) ADDITIONAL EFFICIENCY • Header Compression • Multi-Receiver Aggregation • Bi-Directional Data Flow • BA Enhancements Robust & Scalable MAC Architecture CHANNEL MANAGEMENT • 20/40 MHz Modes Submission 40 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Aggregation Structure Æ Æ Robust Structure Aggregation is a purely-MAC function ■ ■ Æ PHY has no knowledge of MPDU boundaries Simplest MAC-PHY interface Control and data MPDUs can be aggregated Submission 41 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 MAC Header Compression Æ MHDR MPDU carries repeated Header fields Æ CHDATA MPDU refers to previous MHDR MPDU ■ ■ Submission HID field ties the two together Context only within current aggregate 42 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Aggregate Exchange Sequences Æ Aggregate exchange sequences include single frames or groups of frames that are exchanged “at the same time” ■ ■ Æ 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) Submission 43 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Basic Aggregate Exchange Submission 44 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Reverse Direction Data Flow Æ Gives an opportunity for a responder to transmit data to an initiator during the initiator’s TXOP Æ Aggregates data with response control MPDUs Æ Reduces Contention Æ Effective in increasing TCP/IP performance Submission 45 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Reverse Direction Protocol Submission 46 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Link Adaptation Protocol Æ Æ 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 ■ ■ Æ sounding packet calibration exchange Timing of response is not constrained permitting a wide range of implementation options Submission 47 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 Submission doc. : IEEE 802. 11 -04/888 r 3 Link Adaptation Protocol 48 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Multiple Receiver Aggregation Æ Aggregates can contain MPDUs addressed for multiple receiver addresses (MRA) Æ MRA may be followed by multiple responses from the multiple receivers Æ MRA is effective in improving throughput in applications where frames are buffered to many receiver addresses Submission 49 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Periodic Multi-Receiver Aggregation Submission 50 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Multiple Responses Æ MRA contains multiple IAC for ■ ■ Æ One per response At most one per receiver IAC specifies response offset and duration Submission 51 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Protection Mechanisms Æ Long. NAV ■ ■ Æ Pairwise Spoofing ■ ■ Æ An entire sequence is protected by NAV set using MPDU duration field or during contention-free period CF-end packet at end of EDCA TXOP sequence may be used to return unused time by resetting NAV Protection of pairs of PPDUs sent between an initiator and a single responder Uses Legacy PLCP header duration spoofing Single-ended Spoofing ■ ■ Protection of aggregate and any responses using legacy PLCP spoofing at the initiator only Can be used to protect multiple responses Submission 52 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Long. NAV protection Æ Æ Provides protection of a sequence of multiple PPDUs Provides a solution for. 11 b Comes “for free” with polled TXOP Gives maximum freedom in use of TXOP by initiator Submission 53 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Pairwise Spoofing Protection Æ Æ Protects pairs of PPDUs (current and following) Very low overhead, suitable for short exchanges, relies on robust PHY signaling Places Legacy devices into receiving mode for spoofed duration Spoofing is interpreted by HT devices as a NAV setting Submission 54 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Single-Ended Spoofing Protection Æ Æ Protects MRA and all responses Very low overhead, suitable for short exchanges Places legacy devices into receiving mode for spoofed duration Same level of protection as initiator CTS-to-Self ■ Assuming CTS is sent at the lowest rate Submission 55 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Following Packet Descriptor (FPD) Protocol Submission 56 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Operating Mode Selection Æ BSS operating mode controls the use of protection mechanisms and 20/40 width switching by HT STA ■ Æ Supports mixed BSS of legacy + HT devices HT AP-managed modes ■ ■ If only the control channel is overlapped, managed mixed mode provides a low overhead alternative to mixed mode If both channels are overlapped, 20 MHz base mode allows an HT AP to dynamically switch channel width for 40 MHzcapable HT STA Submission 57 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 20 MHz-base Managed Mixed Mode ch_a (control) Carrier Sense (CS) Bcn/ ICB CS CTS self /Bcn CFEnd 40 MHz CS RCB CFEnd 20 MHz t ch_b (extension) NAV ch_a NAV ch_b NAV ch_a+ch_b Submission t NAV 58 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Channel Selection Æ Æ Æ Support 20/40 MHz and 20 MHz operating modes of whole BSS In 20/40 MHz mode, all legacy PPDUs are 20 MHz, all HT PPDUs exchanged between HT STA are either 40 MHz or 20 MHz depending on operating mode and STA capability Channel selection constraints ■ ■ Æ Partial overlap between HT systems is not allowed Legacy STAs are only allowed in the control sub-channel except in 20 MHz-base managed mixed mode An HT AP responds to changes in environment to maintain channel selection constraints Submission 59 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 MIMO Power Management Æ Timed Receive Mode Switching (TRMS) allows a STA to operate with only 1 of its receive chains enabled most of the time ■ ■ Æ Switch to fully enabled when the STA transmits a frame Hold-on timer keeps the STA fully enabled for a known period of time Good for bursty traffic ■ Submission reduced latency compared to other methods of power saving 60 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Enhanced BA Mechanism Æ The originator may omit the inclusion of a BAR frame in an aggregated frame (Implicit BAR). Defines a compressed variant of the 802. 11 e BA MPDU (Compressed BA). ■ ■ Support for non-fragmented BA. This reduces the bitmap size to 1 bit per MSDU. Truncation of the bitmap to reduce the number of MSDUs acknowledged in the bitmap. Aggregation frame MD Æ Initiator D 1 D 2 D 3 D 4 SIFS Compressed BA Responder 1 – 128 Frame Control Duration/ ID Compressed Submission RA Non-Frag TA BA Control Num. MSDU_M 1 61 BA Starting Seq. Control TID Block. Ack. Bitmap FCS BA Bitmap size is fixed through BA setup. Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 MAC Architecture Submission 62 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 CC 27/28 Performance Submission 63 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Selected MAC CC Performance CC# CC 3 CC 18 CC 19 Name Result List of goodput results for usage models 1, 4 and 6. HT Usage Models Supported Non-Qo. S (Measured aggregate throughput / offered aggregate throughput) HT Usage Models Supported (number of Qo. S flows that meet their Qo. S requirements) CC 58 HT Spectral Efficiency Submission 64 HCCA 2 x 2 x 20 2 x 2 x 40 SS 1 (Mbps) 55. 38 83. 92 SS 1 bis n/a 100. 43 SS 4 61. 52 142. 12 SS 4 bis n/a 160. 12 SS 6 45. 51 66. 00 SS 6 bis n/a 96. 24 SS 1 (Mbps/ratio) 2. 87/0. 09 31. 43/0. 24 SS 4 52. 37/0. 11 133. 01/0. 29 SS 6 0. 73/0. 03 21. 24/1 SS 1 17 of 17 SS 4 18 of 18 SS 6 39 of 39 bps/Hz 6. 3 7. 09 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 MAC Summary Æ Baseline Features ■ ■ Æ Additional MAC Efficiency ■ ■ Æ Header Compression Multi-Destination Aggregation Bi-Directional Data Flow Block ACK Compression Legacy Compatible Protection Mechanisms ■ ■ ■ Æ MAC Level Frame Aggregation Qo. S Support (802. 11 e) Long NAV Pairwise Spoofing Single Ended Spoofing Scalable Channel Management ■ Submission 20/40 MHz Operating Modes 65 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 List of References Æ Æ Æ IEEE 802. 11 -04/887, "TGn. Sync Proposal Summary" IEEE 802. 11 -04/888, "TGn. Sync Proposal“ (This document) IEEE 802. 11 -04/889, "TGn. Sync Proposal Technical Specification" IEEE 802. 11 -04/890, "TGn. Sync Proposal FRCC Compliance" IEEE 802. 11 -04/891, "TGn. Sync Proposal PHY Results" IEEE 802. 11 -04/892, "TGn. Sync Proposal MAC Results" IEEE 802. 11 -04/893, "TGn. Sync Proposal MAC 1 Simulation Results" IEEE 802. 11 -04/894, "TGn. Sync Proposal MAC 2 Simulation Results" IEEE 802. 11 -04/895, "TGn. Sync Proposal MAC Simulation Methodology" You may also direct questions to info@tgnsync. org For additional details, refer to http: //www. tgnsync. org Submission 66 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Modifications since Sep 2004 PHY Æ MAC Removed Options ■ ■ ■ Æ Reed Solomon coding 7/8 code rate 400 ns GI ■ ■ Æ Æ Added ■ ■ Removed TSPEC negotiation Packet loss priority Added ■ Block ACK Compression 7/8 code rate as mandatory 400 ns GI as mandatory (800 ns is already mandatory) Submission 67 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Key Features Æ Æ Æ Æ Æ Submission Scalable PHY & MAC Architecture 20 and 40 MHz channels – fully interoperable Data rate scalable to 630 Mbps Legacy interoperability – all modes Robust preamble Transmit beamforming Robust frame aggregation Bi-directional data flow Fast link adaptation 68 Syed Aon Mujtaba, Agere Systems, et. al.
November 2004 doc. : IEEE 802. 11 -04/888 r 3 Glossary Submission 69 Syed Aon Mujtaba, Agere Systems, et. al.
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