tgn sync complete proposal

January 2005

Syed Aon Mujtaba, Agere Systems, et. al.

Slide 1

doc.: IEEE 802.11-04/888r7

Submission

TGn Sync Complete Proposal

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 < [email protected]> 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 <[email protected]>.

Date: 2005-01-15

Author

Name Company Address Phone Email

Syed Aon Mujtaba Agere Systems

555 Union Blvd.,Allentown, PA 18109, USA

+1 610 712 6616 [email protected]

mailto:[email protected]










January 2005


Slide 2

doc.: IEEE 802.11-04/888r7

Submission

Additional Authors:

Name Company email

Adrian P. Stephens Intel Corporation [email protected]

Alek Purkovic Nortel Networks [email protected]

Andrew Myles Cisco Systems [email protected]

Andy Molisch Mitsubishi Electric Corporation [email protected]

Brian Hart Cisco Systems [email protected]

Brian Johnson Nortel Networks [email protected]

Chiu Ngo Samsung Electronics Co Ltd [email protected]

Daisuke Takeda Toshiba Corporation [email protected]

Daqing Gu Mitsubishi Electric Corporation [email protected]

Darren McNamara Toshiba Corporation [email protected]

Dongjun (DJ) Lee Samsung Electronic Co Ltd [email protected]

David Bagby Calypso Consulting [email protected]

Eldad Perahia Cisco Systems [email protected]

Hiroshi Oguma Tohoku University [email protected]

Hiroyuki Nakase Tohoku University [email protected]

Huanchun Ye Atheros Communications [email protected]

Hui-Ling Lou Marvell Semiconductor [email protected]

Isaac Lim Wei Lih Panasonic [email protected]

James Chen Marvell Semiconductor [email protected]

J. Mike Wilson Intel Corporation [email protected]

January 2005


Slide 3

doc.: IEEE 802.11-04/888r7

Submission

[email protected] IncorporatedJohn Ketchum

[email protected] Mitsubishi Electric CorporationJin Zhang

[email protected] SemiconductorPeter Loc

[email protected] Philips ElectronicsPen Li

[email protected] ElectronicsPaul Feinberg

[email protected] NetworksOsama Aboul-Magd

[email protected] van Waes

[email protected] Philips ElectronicsMonisha Gosh

[email protected] CorporationMasahiro Takagi

[email protected] SystemsMary Cramer

[email protected] SystemsLuke Qian

[email protected] for Infocomm ResearchLi Yuan

[email protected] Kobayashi

[email protected] Electronics Co LtdJon Rosdahl

[email protected] CorporationJohn Sadowsky

[email protected] Philips ElectronicsJorg Habetha

[email protected] CorporationJoe Pitarresi

[email protected] Philips ElectronicsJob Oostveen

[email protected] CommunicationsJeff Gilbert

[email protected] Jokela

January 2005


Slide 4

doc.: IEEE 802.11-04/888r7

Submission

[email protected] IncorporatedSubra Dravida

[email protected] IncorporatedSanjiv nanda

[email protected] Electric Co LtdYasuhiro Tanaka

[email protected] CorporationYasuhiko Tanabe

[email protected] SystemsXiaowen Wang

[email protected] CommunicationsWon-Joon Choi

[email protected] Stolpman

[email protected] CorporationTsuguhide Aoki

[email protected] CorporationTomoya Yamaura

[email protected] CorporationTomoko Adachi

[email protected] Philips ElectronicsTeik-Kheong (TK) Tan

[email protected] CorporationTakushi Kunihiro

[email protected] Fukugawa

[email protected] Electronics Co LtdTaekon Kim

[email protected] for Infocomm ResearchSumei Sun

[email protected] CorporationStephen Shellhammer

[email protected] CommunicationsSheung Li

[email protected] Electric Co LtdSeigo Nakao

[email protected] Phiips ElectronicsRonald Rietman

January 2005


Slide 5

doc.: IEEE 802.11-04/888r7

Submission

Yoshiharu Doi Sanyo Electric Co Ltd [email protected]

Youngsoo Kim Samsung Electronic Co Ltd [email protected]

Yuichi Morioka Sony Corporation [email protected]

Yukimasa Nagai Mitsubishi Electric Corporation [email protected]

January 2005


Slide 6

doc.: IEEE 802.11-04/888r7

Submission

Abstract This document describes the TGn Sync

complete proposal submission to IEEE 802.11 TGn

January 2005


Slide 7

doc.: IEEE 802.11-04/888r7

Submission

New TGn Sync Members Infocomm Mitsubishi Electric Corporation Qualcomm Incorporated Sharp Corporation Tohoku University Wavebreaker/ATcrc Wavion

January 2005


Slide 8

doc.: IEEE 802.11-04/888r7

Submission

TGn Sync Mission Statement Develop a scalable architecture to support

present and emerging applications

Foster a broad industry representation across market segments

January 2005


Slide 9

doc.: IEEE 802.11-04/888r7

Submission

Broad Industry Representation OEM / System Vendors

■ Cisco■ Mitsubishi Electric■ Nokia■ Nortel■ Panasonic■ Samsung■ Sanyo■ Sharp■ Sony■ Toshiba■ Wavebreaker/ATcrc■ Wavion

Semi Vendors■ Agere■ Atheros■ Intel■ Marvell■ Philips■ Qualcomm

PC

Enterprise

Consumer Electronics

Asia

Pac

ific

/ Eur

ope

/ Nor

th A

mer

ica

Semiconductor

Handset

Public Access

Academia Academia

■ Infocomm■ Tohoku University

January 2005


Slide 10

doc.: IEEE 802.11-04/888r7

Submission

Scalable Architecture across several dimensions

Performance Over Time

Market Segments

Regulatory Domains North America

EuropeAsia Pacific

140 / 243Mbps315Mbps 630Mbps

ResidentialEnterprisePublic AccessPortable Devices

January 2005


Slide 11

doc.: IEEE 802.11-04/888r7

Submission

… And a well-defined Core

Mandatory Features:■ Two antennas■ 20 / 40MHz

140 / 243 Mbps

January 2005


Slide 12

doc.: IEEE 802.11-04/888r7

Submission

PHY Summary of TGn Sync Proposal Mandatory Features:

■ 1 or 2 Spatial Streams■ 20MHz and 40MHz* channelization■ 1/2, 2/3, 3/4, and 7/8 channel coding rates■ RX assisted Rate Control■ Optimized Interleaver for 20 & 40MHz■ 400ns & 800ns Guard Interval■ Full & seamless interoperability with a/b/g

Optional Features:■ Transmit Beamforming■ Low Density Parity Check (LDPC) Coding

• Completed merger process with LDPC partial proposals ■ support for 3 or 4 spatial streams

*Not required in regulatory domains where prohibited.

140Mbps in 20MHz

243Mbps in 40MHz

NEW

NEW

January 2005


Slide 13

doc.: IEEE 802.11-04/888r7

Submission

MAC Summary of TGn Sync Proposal Mandatory Features:

■ MAC level aggregation ENHANCED■ RX assisted link adaptation■ QoS support (802.11e)■ MAC header compression■ Block ACK compression■ Legacy compatible protection■ 20/40 MHz channel management

Optional Features:■ Bi-directional data flow■ MIMO RX Power management

January 2005


Slide 14

doc.: IEEE 802.11-04/888r7

Submission

PHY

January 2005


Slide 15

doc.: IEEE 802.11-04/888r7

Submission

PHY Architectural Features Mandatory features:

■ Spatial division multiplexing (SDM) of 2 Spatial Streams■ Interoperable 20MHz and 40MHz channelizations■ Channel Coding Rates: 1/2, 2/3, 3/4, and 7/8■ Support for RX assisted Rate Control■ Guard Interval: 400ns and 800ns

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

January 2005


Slide 16

doc.: IEEE 802.11-04/888r7

Submission

Modifications to PHY Arch after San Antonio

Optimized specification for interleaver for both 20 MHz and 40 MHz channelizations

Completed the merger process with LDPC partial proposals■ Detailed specification of LDPC encoding can

be found in 889r2 (TGn Sync Technical Specification)

January 2005


Slide 17

doc.: IEEE 802.11-04/888r7

Submission

Scalable PHY Architecture

Open Loop SDM

RX assisted Rate Control

2 Spatial Streams

20 MHz

Regulatory Constraints

40 MHz

Low Cost & Robust

140 Mbps 243 Mbps

Robustness Enhancement

Closed Loop TX BF

4 Spatial Streams

ThroughputEnhancement

Conv. Coding LDPC

Robustness Enhancement

630 Mbps

Mandatory Optional

January 2005


Slide 18

doc.: IEEE 802.11-04/888r7

Submission

Mapping Spatial Streams to Multiple Antennas Number of spatial streams = Number of TX antennas

■ Direct map 1 spatial stream 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 transmit beamforming

• Optimal technique for realizing array and diversity gains• Requires channel state info at the TX• Supports unequal rates on different spatial streams

■ Optional orthogonal spatial spreading• Exploits all transmit antennas• No channel state info at TX required

■ Due to per spatial stream training, no change is needed at the RX to support optional techniques

January 2005


Slide 19

doc.: IEEE 802.11-04/888r7

Submission

Parameters in Link Adaptation

Basic MIMO Beamformed MIMO

Stream Control No YesRate (MCS) Control Yes Yes (per

stream)GI selection Yes YesTX Per-Tone Steering Matrix No YesPer Stream Power Loading No Yes

January 2005


Slide 20

doc.: IEEE 802.11-04/888r7

Submission

Mandatory PHY Features

January 2005


Slide 21

doc.: IEEE 802.11-04/888r7

Submission

TX Arch: Spatial Division Multiplexinge.g. 2 Spatial streams with 2 TX antennas

Cha

nnel

Enc

oder

Pun

ctur

er

FrequencyInterleaver

ConstellationMapper

iFFTModulator

insertGI

windowsymbols

Pilots

Preamble

Scr

ambl

edM

PD

U


ConstellationMapper

iFFTModulator

insertGI

windowsymbols

Pilots

Preamble

Spa

tial p

arse

r

January 2005


Slide 22

doc.: IEEE 802.11-04/888r7

Submission

Tone Design for 20 and 40 MHz

-58 -6 +6 +58-64 +63

-53 -25 -11 +11 +25 +53

-2 +2-32 +32

Legacy 20 MHz inLower Sub-Channel

Legacy 20 MHz inUpper Sub-Channel

-26 +26-1 +1-21 -7 +7 +21

20 MHz:• Identical to 802.11a• 64 point FFT• 48 data tones• 4 pilot tones

40 MHz:• 128 point FFT• 108 data tones• 6 pilot tones

Tone Fill in the Guard Band

January 2005


Slide 23

doc.: IEEE 802.11-04/888r7

Submission

‡ Duplicate format, BPSK R = ½ provides 6 Mbps for 40 MHz channels½ GI applies to all data rates in 20MHz

Scalable Basic MCS SetModulation 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, 36, 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 MCSOptional MCS

January 2005


Slide 24

doc.: IEEE 802.11-04/888r7

Submission

HT-PPDU Format in 20MHz20

MH

z

AN

T_1

LegendL- Legacy HT- High ThroughputSTF Short Training FieldLTF Long Training FieldSIG Signal Field

Legacy CompatibleCan be decoded by anylegacy 802.11a or g compliant device for interoperability

L-STF L-LTF L-SIG HT-SIG HT-DATA


Legacy Compatible Preamble HT-specific Preamble

HTSTF

HTLTF-1

HTLTF-2

20M

Hz

AN

T_2

January 2005


Slide 25

doc.: IEEE 802.11-04/888r7

Submission

HT-PPDU Format in 40MHz

AN

T_1

AN

T_2

40M

Hz

40M

Hz

Legacy Compatible Preamble HT-specific Preamble

HTSTF

HTLTF-1

HTLTF-2

L-STF L-LTF L-SIG HT-SIG

HT-DATA

DuplicateL-STF

DuplicateL-LTF

Dup.L-SIG

DuplicateHT-SIG


HT-DATA

DuplicateL-STF

DuplicateL-LTF

Dup.L-SIG

DuplicateHT-SIG

January 2005


Slide 26

doc.: IEEE 802.11-04/888r7

Submission

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

L-STF L-LTF L-SIG HT-SIG HT LTF HT LTF Data

Legacy RATE and LENGTH fields => Packet Length in OFDM Symbols

HTSTF

January 2005


Slide 27

doc.: IEEE 802.11-04/888r7

Submission

HT PPDU Detection

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-STF L-LTF L-SIG

orLegacyDATA

Legacy Compatible Preamble

January 2005


Slide 28

doc.: IEEE 802.11-04/888r7

Submission

MIMO AGC

Tone interleaving the L-STF leads to perfect decorrelation■ if L-STF is tone-interleaved, it will hurt legacy interoperability with cross-correlation RX

Cyclic delay across the L-STF is nearly decorrelated■ however, large cyclic delay hurts interoperability with cross-correlation RX■ and, small cyclic delay suffers from inaccurate power estimation, as shown next


single spatial stream multiple spatial streams

powermeasurement

AGC locked

*

1

_ _TXN

j ji jii

Power RX Power TX h h

Accurate measurement of MIMO channel power

requires uncorrelated STFs

*( ) ( ) 0i jE STF f STF f

January 2005


Slide 29

doc.: IEEE 802.11-04/888r7

Submission

Power Fluctuation of L-STF w.r.t Data

-7 -6 -5 -4 -3 -2 -1 0 1 2 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

x = Power fluctuation of AGC setting w.r.t. data power (dB)

STF = Tone InterleavedSTF = Cyclic Delay

CD

F(x)

Power fluctuation with tone interleaving is within 1dB of the data power

Data power

Introduce a dedicated STF for MIMO that is tone interleaved

Reduces 1 bit in the ADC cost & power savings

2x2, TGn Channel DSNR = 30dB

January 2005


Slide 30

doc.: IEEE 802.11-04/888r7

Submission

Power Fluctuation of HT-LTF w.r.t. Data

-10 -8 -6 -4 -2 0 2 40

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

x = Power fluctuation of HT-LTF w.r.t. data (dB)

CD

F(x)

HT-LTF = Tone Interleaved

HT-LTF = Walsh + Cyclic Delay

2x2, TGn Channel DSNR = 30dB

Data power

Large deviation of HT-LTF power wrt data power will result in higher channel estimation error

HT-LTF should be tone interleaved

January 2005


Slide 31

doc.: IEEE 802.11-04/888r7

Submission

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

HT SIG 2 LTS1 LTS2 DATA

DATA

DATA

HT LTF

HT SIG 2

HT SIG 2

HTSTS

HTSTS

HTSTS

LTS1 LTS2

LTS1 LTS2

LTS1 LTS2

LTS1 LTS2

LTS1 LTS2

HT LTFHTSTF

January 2005


Slide 32

doc.: IEEE 802.11-04/888r7

Submission

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

January 2005


Slide 33

doc.: IEEE 802.11-04/888r7

Submission

Legacy Interoperability of PreambleCross Correlation with STS

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5

microseconds

Abs

olut

e Va

lue

of C

ross

Cor

rela

tion

Cross Correlation with STS

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5

microseconds

Abs

olut

e Va

lue

of C

ross

Cor

rela

tion

Cross-correlation of L-STS (TGn Sync)

Cross-correlation of L-STS (WWiSE)

Period = 800ns

Period = 400ns

Potential issues with cross-correlation receivers with WWiSE preamble

January 2005


Slide 34

doc.: IEEE 802.11-04/888r7

Submission

Transmitted Signal

Tx2

Tx1

L-STF L-LTF L-SIG L-DAT

L-STF(400n) L-LTF(3100n) L-SIG(3100n) L-DAT(3100n)

Tx1

Tx2

L-STF

.11a preamble (as used by TGn Sync)L-LTF L-SIG L-DATTx1

WWiSE preamble

Packetgenerator

TGnChannel model

Tx1

Tx2

C simulator Agilent E4438C

Single inputsingle output

signal generator

January 2005


Slide 35

doc.: IEEE 802.11-04/888r7

Submission

Measurement Setup

Compare the RATE and LENGTH

TGn simulator

WLAN cardunder test

Aeropeek NX

Agilent E4438CEnhanced Signal Generator (ESG)

Wireless

5.19GHz10cm apartOmni transmit antenna

RATELENGTH RATE

LENGTH

January 2005


Slide 36

doc.: IEEE 802.11-04/888r7

Submission

WWiSE preamble performance with Autocorrelation RX

Laboratory Test with a legacy autocorrelation RX

"Autocorrelation Vendor" (Channel D)

1.0E-03

1.0E-02

1.0E-01

1.0E+00

-30 -25 -20 -15 -10 -5 0

Relative Tx power [dBm]

Mea

sure

d SI

G F

ER

Legacy w/o CDDLegacy w/ CDD (400nsec)

January 2005


Slide 37

doc.: IEEE 802.11-04/888r7

Submission

WWiSE preamble performance with Crosscorrelation RX

FER Floor!FER Floor!

Performance limitation with a WWiSE preamble

"Cross Correlation Vendor" (Channel model D)

1.0E-03

1.0E-02

1.0E-01

1.0E+00

-30 -25 -20 -15 -10 -5 0Relative Tx power [dBm]

Mea

sure

d SI

G F

ER

Legacy w/o CDDLegacy w/ CDD (400nsec)

January 2005


Slide 38

doc.: IEEE 802.11-04/888r7

Submission

Implication of using WWiSE preambles Legacy devices with a cross-correlation RX will not

correctly decode a WWiSE preamble Hence, such legacy devices will not defer to a

WWiSE HT transmission, potentially creating collisions in the BSS

■ BSS throughput would drop, and latency would increase WWiSE preamble is not legacy compatible Lab test reinforces TGn Sync’s decision to use a

100% backwards compatible legacy preamble

January 2005


Slide 39

doc.: IEEE 802.11-04/888r7

Submission

TGn Sync enhanced interleaver11a Bit interleaver,

PermutationOperation 1

parser

FrequencyRotation

SISO (11a/g)

MIMO 2x11a Bit interleaver,

PermutationOperation 1

11a Bit interleaver,PermutationOperation 2




Channelization 20MHz 40MHz

Total # of Streams 1 2 3 4 1 2 3 4

1st stream 0 0 0 0 0 0 0 0

2nd stream 22 22 22 58 58 58

3rd stream 11 11 29 29

Freq

uenc

y R

otat

ion

4th stream 33 87

1st Spatial Stream

2nd, 3rd, or 4th Spatial Stream

January 2005


Slide 40

doc.: IEEE 802.11-04/888r7

Submission

0 5 10 15 20 25 30 35 4010

-2

10-1

100

2x2x20MHz, Channel B-NLOS, MCS 8-15

SNR, dB

PE

R

Original interleaverUpdated interleaver

Enhanced Interleaver Results1 to 2dB gain

January 2005


Slide 41

doc.: IEEE 802.11-04/888r7

Submission

2 vs 4 pilots in MIMO■ The TGn Sync Proposal uses the full 4 pilots (like .11a/b/g)

• 2 pilots in WWiSE provide marginal data rate increase: < 4%■ Full CC67 sims to compare multi- and single-stream cases:

• Since data also will have diversity gain, and thus require less operating SNR, would the pilots now limit performance?

• Single stream modes important: CDD (TGn Sync) , STBC (WWiSE)■ Analysis must consider differences in 11n vs. 11a:

• Different preambles, antenna configurations• Decoded data SNR improved due to MIMO (e.g, MRC, STBC)• Thus pilot accuracy requirements also increase• Comparing 11n pilot SNR to 11a is thus not sufficient

■ Robustness to narrowband interference and impairments• These both reduce effective number of pilots – thus need margin

■ Full details in doc. 11-05/1636r0

January 2005


Slide 42

doc.: IEEE 802.11-04/888r7

Submission

Dual Stream Performance2 vs 4 Pilots with 2 streams, 2x2, E NLOS

1.E-03

1.E-02

1.E-01

1.E+00

5 10 15 20Average SNR [dB]

Pac

ket E

rror

Rat

e

2 streams, BPSK, 1/2, 2 pilots

2 streams, BPSK, 1/2, 4 pilots

1 dB

January 2005


Slide 43

doc.: IEEE 802.11-04/888r7

Submission

Single Stream Performance2 vs 4 Pilots with single stream, 2x2, E NLOS

1.E-03

1.E-02

1.E-01

1.E+00

5 10 15 20Average SNR [dB]

Pac

ket E

rror

Rat

e

1 stream, BPSK, 1/2, 2 pilots

1 stream, BPSK, 1/2, 4 pilots

3.5 dB

January 2005


Slide 44

doc.: IEEE 802.11-04/888r7

Submission

Summary of 2 vs 4 pilots Quantitative analyses show that using only 2 pilots

causes significant performance degradation in many situations

■ 4 vs 2 pilots compared for 2x2 basic MIMO channel E• Dual stream: ~1dB loss• Single stream: 1.5~3.5dB loss.

■ Robustness• Performance loss w/ narrow-band interference or impairments:

– 4 ~ 6dB loss with 2 pilots -> NOT ROBUST !!

Performance penalty of using only 2 pilots is not justified by the less than 4% data rate increase

January 2005


Slide 45

doc.: IEEE 802.11-04/888r7

Submission

Importance of Rate Feedback and Stream Control

Throughput is maximized if there is rapid convergence to a good choice of stream count and MCS

■ Initial MCS/stream selection ■ Ongoing tracking and optimization

Receiver determines its preferred stream count and MCS■ Based on observation of received HT-LTF in sounding packet■ Sends this choice back to transmitter using MCS Feedback (MFB)

Transmitter makes a rate choice based on the MCS selection at RX

■ Under some circumstances, e.g. pairwise spoofing, TX must adhere to MFB

Important for Basic MIMO, Spatial Spreading and Beamforming

January 2005


Slide 46

doc.: IEEE 802.11-04/888r7

Submission

Rate feedback in Basic MIMO MRQ (MCS Request) is sent in sounding packet:

■ RX gets estimate of full H matrix■ Channel quality estimates based on H matrix guide rate and

stream selection

TX RX

MRQ payload in PHY sounding packet

Full H matrix

Number of streams and coding rate carried in MFB

h11Ant1

Ant2

h12

h21

h22

2

1

2212

2111

hh

hhhh

H

January 2005


Slide 47

doc.: IEEE 802.11-04/888r7

Submission

Stream/Rate Control Approaches SNR calculation performed at equalizer

output:■ Can provide stream count and MCS selection■ Includes impairments due to channel estimation

errors SNR calculation performed by re-encoding

decoded data and comparing it against decoder input:■ allows MCS selection, but not stream count

January 2005


Slide 48

doc.: IEEE 802.11-04/888r7

Submission

Close Loop vs Open Loop Throughput Comparison■ Open loop vs closed loop comparison for 2x2■ TxBf = Transmit Beamforming; SS=Spatial spreading

Open vs. Closed loop

0

20

40

60

80

100

120

140

160

180

200

10 15 20 25 30 35 40 45 50

SNR [dB]

MA

C th

roug

hput

[Mbp

s]

TxBf 2%SS closed loop 2%SS open loop 2%TxBf 10%SS closed loop 10%SS open loop 10%

January 2005


Slide 49

doc.: IEEE 802.11-04/888r7

Submission

MSDU Delay CDFTarget PHY PER = 10%

SS open loop 10% PER

SS closed loop 10% PER

TxBf closed loop 10% PER

January 2005


Slide 50

doc.: IEEE 802.11-04/888r7

Submission

Is 40MHz Mandatory? Both 20 MHz & 40 MHz capabilities are

mandatory■ With exceptions due to regulatory requirements

Capability depends on regulatory domain (just like channelization plans):■ 20/40 MHz capable devices■ 20 MHz only capable devices

Both types of devices are fully interoperable

January 2005


Slide 51

doc.: IEEE 802.11-04/888r7

Submission

20/40 MHz Operation

20/40 MHz Region(e.g. in US/Europe)

20 MHz Region(e.g. in Japan)

20/40 MHz Capable Device

(e.g. in US/Europe)40 MHz Operation

(20 MHz Operation)20 MHz Operation;40 MHz disabled

20 MHz only Capable Device(e.g. in Japan)

Seamless 20 MHz operation in a 40

MHz BSS20 MHz Operation

Where Used

Where Bought

January 2005


Slide 52

doc.: IEEE 802.11-04/888r7

Submission

Why 40MHz is Mandatory?

0

20

40

60

80

100

120

140

160

180

200

220

240

260

0 5 10 15 20 25 30 35

SNR (dB)

Ove

r the

Air

Thro

ughp

ut (M

bps)

2x2-40 MHz

4x4-20 MHz

2x2-20 MHz w/ short GI

2x3-20 MHz w/ short GI

2x2 – 40 MHz• Only 2 RF chains => Cost effective & low power• Lower SNR at same throughput => Enhanced robustness

Basic MIMO MCS setNo impairments1000 byte packetsTGn channel model B

Sweet spot for 100Mbps top-of-MAC

January 2005


Slide 53

doc.: IEEE 802.11-04/888r7

Submission

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 as the 20 MHz sub-channel with

higher energy, cross-correlation or autocorrelation, etc.

40 MHz PPDU into a 20 MHz receiver■ One 20 MHz sub-channel is sufficient to decode the L-SIG and the HT-SIG■ 20 MHz RX (either HT or legacy) will defer properly to 40 MHz PPDU

See MAC slides for additional information on 20/40 inter-op

January 2005


Slide 54

doc.: IEEE 802.11-04/888r7

Submission

Optional PHY Features

January 2005


Slide 55

doc.: IEEE 802.11-04/888r7

Submission

Seamless Arch Extension for TX BFe.g. 2 Spatial Streams across 3 Transmit Antennas

Cha

nnel

Enc

oder

Pun

ctur

er


ConstellationMapper

Pilots

HT LTF

Scr

ambl

edM

PD

U


ConstellationMapper

Pilots

Spat

ial S

teer

ing

Mat

rix

Per Spatial Stream Processing:HT-LTF & HT-Data undergo same spatial transformation iFFT

Mod.insert

GI win

dow

iFFTMod.

insertGI

iFFTMod.

insertGI

win

dow

win

dow

Spa

tial P

arse

r

HT LTF

January 2005


Slide 56

doc.: IEEE 802.11-04/888r7

Submission

0

20

40

60

80

100

120

140

160

0 5 10 15 20 25 30 35

SNR (dB)

Ove

r-th

e-A

ir Th

roug

hput

(Mbp

s)

2x2 - SDM

2x3 - SDM

2x2 - Advanced BF

3x2 - Advanced BF

4x2 - Advanced BF

Why introduce TX Beamforming?

1000 byte packetsNo impairment20MHz, channel D

4 TX-antenna AP 2 RX-antenna client ~10 dB gain of 4x2-ABF over 2x2-SDM => cost effective client

January 2005


Slide 57

doc.: IEEE 802.11-04/888r7

Submission

WWiSE proposal can not support Tx Beamforming

Problem■ WWiSE channel estimation requires smoothing

algorithms■ Channel smoothing cannot be applied with MIMO

Beamforming

Problem■ WWiSE GF structure does not allow omni-directional

transmission of SIG-N■ Result: Hidden node problems

ref: doc. 11-05/1635r1

January 2005


Slide 58

doc.: IEEE 802.11-04/888r7

Submission

Why smoothing is bad for MIMO BF? Smoothing requires high adjacent tone coherence However, we must estimate the combined channel

Heffective = Hchannel * Vbeamforming■ Beamforming matrix has poor adjacent tone coherence

Why?■ Eigen-channel rank reversals

• For each tone, eigen-channels are ranked by singular values• Eigen-channels can reverse ranks on adjacent tones – resulting in

an adjacent tone swap of corresponding columns of BF matrix• Result – very low adjacent tone coherence

January 2005


Slide 59

doc.: IEEE 802.11-04/888r7

Submission

Example: 4x4, Channel D

-20

-15

-10

-5

0

5

10

15

-10 -8 -6 -4 -2 0 2 4 6 8 10Frequency (MHz)

Sing

ular

Val

ue (d

B)

0.75

0.80

0.85

0.90

0.95

1.00

-10 -8 -6 -4 -2 0 2 4 6 8 10

Frequency (MHz)

abs(

rho

)

January 2005


Slide 60

doc.: IEEE 802.11-04/888r7

Submission

Optional 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

January 2005


Slide 61

doc.: IEEE 802.11-04/888r7

Submission

0

20

40

60

80

100

120

140

0 5 10 15 20 25 30 35

SNR (dB)

Thro

ughp

ut (M

bps)

Conv.

LDPC

Basic MIMO MCS SetNo Impairments1000 byte packets2x2, NLOS Channel EConstraint PER < 2%

Benefit of LDPC Coding

4 dB of coding gain

January 2005


Slide 62

doc.: IEEE 802.11-04/888r7

Submission

PHY Summary Mandatory Rate of 140Mbps in 20MHz:

■ 2 Spatial Streams■ 7/8th rate coding■ 400ns Guard Interval■ RX assisted Rate Control

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

January 2005


Slide 63

doc.: IEEE 802.11-04/888r7

Submission

MAC

January 2005


Slide 64

doc.: IEEE 802.11-04/888r7

Submission

Scalable MAC Architecture

BASELINE MAC•Robust Aggregation•QoS Support (802.11e)•Rx assisted link adapt.

ADDITIONAL EFFICIENCY•Header Compression•Multi-Receiver Aggregation•Bi-Directional Data Flow•BA Enhancements

LEGACY INTEROP.•Long NAV•Pairwise Spoofing•Single-Ended Spoofing

CHANNEL MANAGEMENT•20/40 MHz Modes

Robust&

ScalableMAC

Architecture

January 2005


Slide 65

doc.: IEEE 802.11-04/888r7

Submission

Modifications to MAC Arch November 2004 to January 2005

■ Added A-MSDU aggregation

January 2005


Slide 66

doc.: IEEE 802.11-04/888r7

Submission

Baseline MAC Features

January 2005


Slide 67

doc.: IEEE 802.11-04/888r7

Submission

A-MPDU Aggregation StructureM

PD

UH

eade

r

Leng

thC

RC

MP

DU

Pay

load

FC

S

MP

DU

Hea

der

Leng

thC

RC

MP

DU

Pay

load

FC

S

MP

DU

Hea

der

Leng

thC

RC

MP

DU

Pay

load

FC

S

MP

DU

Del

imite

r

MP

DU

PSDU

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

January 2005


Slide 68

doc.: IEEE 802.11-04/888r7

Submission

A-MSDU Aggregation Structure

FrameControl Dur / ID Address

1Address

2Address

3Seq

ControlQoS

ControlAddress

4A-

MSDU FCS

Subframe 1 Subframe 2 Subframe n...

SubframeHeader MSDU Pad

DA SA Len

0-2304 B 0-3 B14 B

6B 6B 2B

Carrier MPDU

•Efficient Structure

•MSDUs of the same TID can be aggregated

•MSDUs with differing SA/DA can be aggregated

January 2005


Slide 69

doc.: IEEE 802.11-04/888r7

Submission

A-MPDU Aggregate Exchange Sequences

A-MPDU 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)

January 2005


Slide 70

doc.: IEEE 802.11-04/888r7

Submission

Dat

a M

PDU

Agg

PPD

UD

ata

MPD

U

Dat

a M

PDU

Initi

ator

Tx

Activ

ityPH

Y Tx

MAC

Tx

Res

pond

er T

x Ac

tivity

PHY

TxM

AC T

x

Non

-agg

PPD

UBl

ock

Ack

Basi

c ra

teno

n-ag

gR

TS

Basi

c ra

teno

n-ag

gC

TS

Dat

a M

PDU

Agg

PPD

UD

ata

MPD

U

Dat

a M

PDU

Non

-agg

PPD

UBl

ock

Ack

Dat

a M

PDU

Dat

a M

PDU

Dat

a M

PDU

Dat

a M

PDU

Dat

a M

PDU

Dat

a M

PDU

Implicit BlockAck Protocol

RTS/CTSProtocol

Dat

a M

PDU

Dat

a M

PDU

Basic Aggregate Exchange

January 2005


Slide 71

doc.: IEEE 802.11-04/888r7

Submission

RX Assisted 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

January 2005


Slide 72

doc.: IEEE 802.11-04/888r7

Submission

RX Assisted Link Adaptation Protocol

January 2005


Slide 73

doc.: IEEE 802.11-04/888r7

Submission

Features Providing Additional Efficiency

January 2005


Slide 74

doc.: IEEE 802.11-04/888r7

Submission

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

January 2005


Slide 75

doc.: IEEE 802.11-04/888r7

Submission

Agg

PP

DU

Initi

ator

Tx

Act

ivity

PH

Y T

xM

AC

Tx

Res

pond

er T

x A

ctiv

ityP

HY

Tx

MA

C T

x

Bas

ic ra

teno

n-ag

gIA

C M

PD

U(R

TS+

RD

L)

Bas

ic ra

teno

n-ag

gR

AC

MP

DU

(CTS

+RD

R)

Dat

a M

PD

U

Agg

PP

DU

Dat

a M

PD

U

BA

MP

DU

Agg

PP

DU

Blo

ck A

ck

Dat

a M

PD

UD

ata

MP

DU

Dat

a M

PD

U

RA

C M

PD

U

IAC

MP

DU

(RD

G)

Reverse DirectionProtocol

BA

R M

PD

U

Dat

a M

PD

UD

ata

MP

DU

IAC

MP

DU

RD

GD

urat

ion

Dat

a M

PD

U

Dat

a M

PD

U

Reverse Direction Protocol

January 2005


Slide 76

doc.: IEEE 802.11-04/888r7

Submission

Enhanced BA Mechanism

Aggregation frameM

D D1 D2 D3 D4Initiator

ResponderCompressed

BA

SIFS

The originator may omit the inclusion of a BAR frame in an aggregated frame (Implicit BAR). Defines a compressed variant of the 802.11e 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.

Compressed Non-Frag Num MSDU TID

1 – 128 Frame

ControlDuration/

ID RA TA BA Control

BA Starting Seq. Control BlockAckBitmap FCS

BA Bitmap size is fixed through BA setup.

January 2005


Slide 77

doc.: IEEE 802.11-04/888r7

Submission

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

January 2005


Slide 78

doc.: IEEE 802.11-04/888r7

Submission

Multiple ResponsesIAC:

OffsetDuration

IAC:Offset

Duration

IAC:Offset

Duration

Initiator’s PPDU

Response from RA2

Response from RA 3

Duration 1

Duration 3

Offset 1

Duration 2E

nd o

f PP

DU Offset 2

Offset 3

Response from RA1

MRA contains multiple IAC for ■ One per response■ At most one per receiver

IAC specifies response offset and duration

January 2005


Slide 79

doc.: IEEE 802.11-04/888r7

Submission

Legacy Interoperability and Channel Management

January 2005


Slide 80

doc.: IEEE 802.11-04/888r7

Submission

Protection Mechanisms LongNAV

■ 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

Pairwise Spoofing■ 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

January 2005


Slide 81

doc.: IEEE 802.11-04/888r7

Submission

LongNAV protection Provides protection of a sequence of multiple PPDUs Provides a solution for .11b Comes “for free” with polled TXOP Gives maximum freedom in use of TXOP by initiator

RAC(CTS)

IAC(RTS) Agg

Agg

Agg

Agg

CF-End

NAV Value

NAV Value

Nom

inal

End

of T

XO

P

Nav Timer Non-Zero

Resetsthe

NAV

January 2005


Slide 82

doc.: IEEE 802.11-04/888r7

Submission

Pairwise Spoofing Protection 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

January 2005


Slide 83

doc.: IEEE 802.11-04/888r7

Submission

Single-Ended Spoofing Protection 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

January 2005


Slide 84

doc.: IEEE 802.11-04/888r7

Submission

Operating Mode Selection BSS operating mode controls the use of protection

mechanisms and 20/40 width switching by HT STA■ 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 MHz-capable HT STA

January 2005


Slide 85

doc.: IEEE 802.11-04/888r7

Submission

20 MHz-base Managed Mixed Mode

ch_a (control)

CTSself/Bcn

CF-End

tch_b (extension)

Bcn/ICB

CF-End

CF-End

tRCB

NAV

NAV

NAVNAV

NAVch_a

NAVch_b

NAVch_a+ch_b

20MHz

40MHz20MHz

CarrierSense(CS)

CS

CS

January 2005


Slide 86

doc.: IEEE 802.11-04/888r7

Submission

System Simulation Results Compliant to TGn FRCC requirements 3 independent MAC simulations

■ 802.11-04/893■ 802.11-04/894■ 802.11-04/1359

FRCC Results and analysis of MAC features is presented in 802.11-04/892

Detailed description of MAC simulation methodology in 802.11-04/895

January 2005


Slide 87

doc.: IEEE 802.11-04/888r7

Submission

Selected System CC PerformanceCC# Name Result HCCA

2x2x20 2x2x40

CC3 List of goodput results for usage models 1, 4 and 6.

SS1 (Mbps) 84 84

SS1 + 87 135

SS4 90 160

SS4 + 98 189

SS6 66 66

SS6 + 85 166

CC18 HT Usage Models SupportedNon-QoS(Measured aggregate throughput / offered aggregate throughput)

SS1(Mbps/ratio)

31/1.0 31/1.0

SS4 81/18 151.033 SS6 21/1.0 21/1.0

CC19 HT Usage Models Supported

(number of QoS flows that meet their QoS requirements)

SS1 17 of 17 17 of 17

SS4 18 of 18 18 of 18

SS6 39 of 39 39 of 39

CC58 HT Spectral Efficiency bps/Hz 5.3 5.94

January 2005


Slide 88

doc.: IEEE 802.11-04/888r7

Submission

Value of MAC FeaturesFeatur

e Value Condi-tion

S1 (Mbps) S4 (Mbps) S6 (Mbps)

TGn bis TGn bis TGn bis

Pairwise spoofing

(vs LongNav)6-

10%Long NAV 70.25 - 71.57 - 49.92 -Pairwise Spoofing 77.52 - 78.64 - 53.06 -

Enhanced BA

2 - 12%

- 73.30 - 92.40 - 63.80 -+ 75.40 - 103.3 - 65.10 -

Reverse Direction

5 - 36%

- 82.08 87.26 90.60 126.91 62.56 66.96

+ 83.85* 94.67 123.2

8 141.0

2 66.00 96.24

26 -56%

+Periodic RDR - - 142.1

2 160.1

2 - -

Header Compressio

n1-6%

- 82.08 87.26 90.60 126.91 62.56 66.96

+ 83.39* 87.98 96.79 127.9

8 62.72 68.56

January 2005


Slide 89

doc.: IEEE 802.11-04/888r7

Submission

Comparison of TGnSync and WWiSE System Simulation results

References:11-04-892r3 – TGnSync MAC results11-04-877r8 – WWiSE MAC results

January 2005


Slide 90

doc.: IEEE 802.11-04/888r7

Submission

System Simulation Results

“+” scenarios have all BE traffic offered load increased to 100 mbps (s-1) or 30 mbps (s-4,6)“*” - 1 QOS flow missed PLR targetThese results will improve when advanced beamforming, MRMRA and periodic RDR options are added

Blue = TGnSyncBlue = TGnSyncBlack = WWiSEBlack = WWiSE

CC# Name Scenario EDCA HCCACC3 Goodput 1 7575/67/67 8484/83/83

1+ 9595/71/71 135135/121/1214 142142/124/124

** 160160/178/1784+ 164164/127/127 189189/186/1866 6666/64/64 6666/65/65

6+ 8888/70/70 166166/105/105

January 2005


Slide 91

doc.: IEEE 802.11-04/888r7

Submission

System Simulation Results

TGnSync MAC results significantly outperform WWiSE

MAC Goodput: EDCA

020406080

100120140160180

1+ 4+ 6+

TGnSync

WWiSE

January 2005


Slide 92

doc.: IEEE 802.11-04/888r7

Submission

MAC Efficiency

Blue = TGnSyncBlue = TGnSyncBlack = WWiSEBlack = WWiSE

CC# Name Scenario EDCA HCCA

CC24 MAC Efficiency

11 3232/27/27 3232/33/331+1+ 3636/28/28 5151/47/4744 5050/47/47 5656/67/67

4+4+ 5858/48/48 6767/70/7066 2424/25/25 2424/25/25

6+6+ 3232/27/27 6262/40/40

January 2005


Slide 93

doc.: IEEE 802.11-04/888r7

Submission

MAC Efficiency

TGnSync MAC efficiency significantly outperforms WWiSE

MAC Efficiency: EDCA

0

10

20

30

40

50

60

70

1+ 4+ 6+

TGnSync

WWiSE

January 2005


Slide 94

doc.: IEEE 802.11-04/888r7

Submission

MAC Summary Baseline Features

■ MAC Level A-MPDU and A-MSDU Aggregation■ QoS Support (802.11e)■ Receiver assisted link adaptation

Additional MAC Efficiency■ Header Compression■ Multi-Receiver Aggregation■ Bi-Directional Data Flow■ Enhanced Block ACK

Legacy Compatible Protection Mechanisms■ Long NAV■ Pairwise Spoofing■ Single Ended Spoofing

Scalable Channel Management■ 20/40 MHz Operating Modes

January 2005


Slide 95

doc.: IEEE 802.11-04/888r7

Submission

List of References IEEE 802.11-04/887, "TGnSync Proposal Summary" IEEE 802.11-04/888, "TGnSync Proposal“ (This document) IEEE 802.11-04/889, "TGnSync Proposal Technical Specification" IEEE 802.11-04/890, "TGnSync Proposal FRCC Compliance" IEEE 802.11-04/891, "TGnSync Proposal PHY Results" IEEE 802.11-04/892, "TGnSync Proposal MAC Results" IEEE 802.11-04/893, "TGnSync Proposal MAC1 Simulation Results" IEEE 802.11-04/894, "TGnSync Proposal MAC2 Simulation Results“ IEEE 802.11-04/1359, "TGnSync Proposal MAC3 Simulation Results“ IEEE 802.11-04/895, "TGnSync Proposal MAC Simulation Methodology"

You may also direct questions to [email protected] For additional details, refer to http://www.tgnsync.org

January 2005


Slide 96

doc.: IEEE 802.11-04/888r7

Submission

Modifications since Nov 2004

Optimized■ interleaver specification for 20

MHz and 40 MHz channelizations

Completed merger process with LDPC partial proposals

Added■ A-MSDU aggregation

PHY MAC

January 2005


Slide 97

doc.: IEEE 802.11-04/888r7

Submission

Scalable Architecture across several dimensions

Performance Over Time

Market Segments

Regulatory Domains North America

EuropeAsia Pacific

140 / 243Mbps315Mbps 630Mbps

■ MRMRA• Efficiency for isochronous clients (VoIP)

■ MRAD • Power saving support for portable devices

■ Reverse direction • Higher network efficiency for bulk data transfer

Enterprise■ Lower 802.11n rates

• Range extension and robustness for handsets

■ MRMRA • Power savings and robustness for handset

mobility

Portable Devices

■ Tx beamforming • Extended range for Hot Spot

■ RX assisted Link Adaptation• Higher throughput in congested

environments

Public Access

Residential Tx Beamforming

■ Coverage throughout the home Reverse direction

■ Increased efficiency for gaming

ResidentialEnterprisePublic AccessPortable Devices

January 2005


Slide 98

doc.: IEEE 802.11-04/888r7

Submission

Key Features 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

January 2005


Slide 99

doc.: IEEE 802.11-04/888r7

Submission

GlossaryCRC Cyclic Redundancy Check MPDU MAC protocol data unit

Agg Aggregate MRADMulti-receiver aggregate descriptor

BA Block Ack MRQ MCS requestBAR Block Ack Request MSDU MAC service data unitBSS Basic service set NAV Network allocation vectorCHDATA Compressed header data Non-Agg Non-AggregateCTS Clear to send PPDU PHY protocol data unitFCS Frame checksum QoS Quality of Service

HCCAHybrid controlled channel access RAC Responder aggregate control

IAC Initiator aggregate control RDG Reverse direction grantMAC Medium access controller RDL Reverse direction limitMCS Modulation and coding RDR Reverse direction requestMFB MCS feedback RTS Ready to sendMHDR MAC header MPDU TXOP Transmit opportunity

January 2005


Slide 100

doc.: IEEE 802.11-04/888r7

Submission

MAC Backup

January 2005


Slide 101

doc.: IEEE 802.11-04/888r7

Submission

MAC Challenges in HT Environment HT requires an improvement in MAC Efficiency HT requires effective Rate Adaptation HT requires Legacy Protection

0%

10%

20%

30%

40%

50%

60%

70%

80%

0 5 10 15 20 25

Packet Size (KB)

MAC

Effi

cien

cy

Basic Rate 54 Mbps

Basic Rate 6 Mbps

January 2005


Slide 102

doc.: IEEE 802.11-04/888r7

Submission

MAC Header CompressionOctets: 2 2 6 6 6 1 1 2 4

Frame Control Duration Address 1 Address 2 Address 3 HID Reserved QoS

Control FCS

MAC Header

1

Octets: 2 2 1 1 n 4

Frame Control

Sequence Control HID Reserved Payload Data FCS

Compressed Header

1

MHDR MPDU carries repeated Header fields

CHDATA MPDU refers to previous MHDR MPDU■ HID field ties the two together■ Context only within current aggregate

January 2005


Slide 103

doc.: IEEE 802.11-04/888r7

Submission

Periodic Multi-Receiver Aggregation

January 2005


Slide 104

doc.: IEEE 802.11-04/888r7

Submission

Following Packet Descriptor (FPD) Protocol

Agg

PPD

U

Initi

ator

Tx

Activ

ityPH

Y Tx

MAC

Tx

Res

pond

er T

x Ac

tivity

PHY

TxM

AC T

x

Dat

a M

PDU

FPDProtocol

Spoofed PLCP Length

Spoofed Length

Note, duration value ofEIFS-DIFS which is NOTincluded in the spoofed

PLCP LengthIAC

MPD

U(F

PD:L

engt

h)

Dat

a M

PDU

Dat

a M

PDU

Agg

PPD

UBl

ock

ACK

RAC

MPD

U(M

FB:R

ate)

Agg

PPD

U

IAC

MPD

U

Spoofed

Dat

a M

PDU

Dat

a M

PDU

Non

-Agg

PPD

UBl

ock

ACK

Non

-Agg

PPD

UIA

C M

PDU

(FPD

:Len

gth)

Non

-Agg

PPD

UR

AC M

PDU

(MFB

:Rat

e)

Spoofed Length

Spoofed

Length / Rate Length / Rate

Dat

a M

PDU

Dat

a M

PDU

January 2005


Slide 105

doc.: IEEE 802.11-04/888r7

Submission

MIMO Power Management Timed Receive Mode Switching (TRMS) allows a STA to

operate with only 1 of its receive chains enabled most of the time

■ 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

■ reduced latency compared to other methods of power saving

January 2005


Slide 106

doc.: IEEE 802.11-04/888r7

Submission

Channel Selection 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■ 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

January 2005


Slide 107

doc.: IEEE 802.11-04/888r7

Submission

MAC Architecture

DCFHCCA

RDG

Aggregation

Aggregate ExchangeSequences

EDCA

RTS/CTS/Data/ACKexchange Sequences

MRAD / IAC / RAC /MHDR / CHDATA RTS / CTS / DATA / Ack MPDU Formats

Aggregation Format

ChannelAccess

MethodsFrame

ExchangeSequences

LinkManagement

Indirect RateAdaptation based on

Missing AckClosed Loop Link Adaptation

Transmit Opportunity802.11n

802.11e

802.11

Key

Block Ack

IAC/RAC

RDR/ RDG

802.11n

MHDR/CHDATA

January 2005


Slide 108

doc.: IEEE 802.11-04/888r7

Submission

PHY Backup Slides

January 2005


Slide 109

doc.: IEEE 802.11-04/888r7

Submission

Spatial Stream Tone Interleaving1 SpatialStream

2 SpatialStreams

3 SpatialStreams

4 SpatialStreams

• 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

January 2005


Slide 110

doc.: IEEE 802.11-04/888r7

Submission

HT-SIG Contents

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

MCS (6 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

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

MCS (6 bits)HTLENGTH (18 bits)

AD

V C

OD

ING

(1 b

it)

NU

MB

ER

HT-

LTF

(2 b

its)

SC

RA

MB

LER

INIT

(2 b

its)

CRC (8 bits) SIGNAL TAIL (6 bits)

HT-SIG1

Transmit Order

SO

UN

DIN

G P

AC

KE

T (1

bit)

SH

OR

T G

I (1

bit)

AG

GR

EG

ATE

(1 b

it)

20/4

0 B

W (

1 bi

t)

RE

SE

RV

ED

(1 b

it)

HT-SIG2

tgn sync complete proposal

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