doc.: ieee 802.11-04/888r0 submission august 2004 aon mujtaba, agere systems, et alslide 1 tgn sync...

August 2004

Aon Mujtaba, Agere Systems, et al

Slide 1

doc.: IEEE 802.11-04/888r0

Submission

TGn Sync ProposalDate: Aug 13, 2004

Aon Mujtaba, Agere Systems Inc., ([email protected])Adrian P Stephens, Intel Corporation, ([email protected])

Alek Purkovic, Nortel Networks ([email protected])Andrew Myles, Cisco Systems ([email protected])

Brian Johnson, Nortel Networks Corporation, ([email protected])Daisuke Takeda, Toshiba Corporation, ([email protected])

Darren McNamara, Toshiba Corporation, ([email protected])Dongjun (DJ) Lee, Samsung Electronics Co. Ltd., ([email protected])

David Bagby, Calypso Consulting, ([email protected])Eldad Perahia, Cisco Systems, ([email protected])

Huanchun Ye, Atheros Communications Inc., ([email protected])Hui-Ling Lou, Marvell Semiconductor Inc., ([email protected])James Chen, Marvell Semiconductor Inc., ([email protected])

James Mike Wilson, Intel Corporation, ([email protected]) Jan Boer, Agere Systems Inc., ([email protected])

Jari Jokela, Nokia, ([email protected])Jeff Gilbert, Atheros Communications Inc., ([email protected])

Joe Pitarresi, Intel Corporation, ([email protected]) Jörg Habetha, Royal Philips Electronics, ([email protected])

John Sadowsky, Intel Corporation, ([email protected])Jon Rosdahl, Samsung Electronics Co. Ltd., ([email protected])

Luke Qian, Cisco Systems, ([email protected])Mary Cramer, Agere Systems ([email protected])

mailto:[email protected]



mailto:([email protected]

mailto:([email protected]












August 2004


Slide 2

doc.: IEEE 802.11-04/888r0

Submission

Authors (continued)Masahiro Takagi, Toshiba Corporation, ([email protected])Monisha Ghosh, Royal Philips Electronics, ([email protected])

Nico van Waes, Nokia, ([email protected])Osama Aboul-Magd, Nortel Networks Corporation, ([email protected])

Paul Feinberg, Sony Electronics Inc., ([email protected])Pen Li , Royal Philips Electronics ([email protected])

Peter Loc, Marvell Semiconductor Inc., ([email protected])Pieter-Paul Giesberts, Agere Systems Inc., ([email protected])Richard van Leeuwen, Agere Systems Inc., ([email protected])

Ronald Rietman, Royal Philips Electronics, ([email protected])Seigo Nakao, SANYO Electric Co. Ltd., ([email protected])

Sheung Li, Atheros Communications Inc., ([email protected])Stephen Shellhammer, Intel, ([email protected])

Takushi Kunihiro, Sony Corporation, ([email protected])Teik-Kheong (TK) Tan, Royal Philips Electronics, ([email protected])

Tomoko Adachi, Toshiba Corporation, ([email protected])Tomoya Yamaura, Sony Corporation, ([email protected])

Tsuguhide Aoki, Toshiba Corporation, ([email protected])Won-Joon Choi, Atheros Communications Inc., ([email protected])

Xiaowen Wang, Agere Systems Inc., ([email protected])Yasuhiko Tanabe, Toshiba Corporation, ([email protected])

Yasuhiro Tanaka, SANYO Electric Co. Ltd., ([email protected]) Yoshiharu Doi, SANYO Electric Co. Ltd., ([email protected])

Yuichi Morioka, Sony Corporation, ([email protected])Youngsoo Kim, Samsung Electronics Co. Ltd., ([email protected])





















August 2004


Slide 3

doc.: IEEE 802.11-04/888r0

Submission

TGn Sync Proposal Team - Background

• Team operated as a technical group to help motivate a rapid introduction of the 802.11n standard

• Participating companies from a broad range of markets• PC• Enterprise• Consumer Electronics• Semiconductor• Handset• Public Access

• Solution incorporates a worldwide perspective of perceived market demand and regulatory concerns – Team has representation from the US, Europe and the Pacific Rim

August 2004


Slide 4

doc.: IEEE 802.11-04/888r0

Submission

Proposal Overview• High throughput and minimal design complexity

– Superior robustness for a broad range of applications– Low cost, low power consumption

• Scalable architecture • Seamless interoperability with 802.11 legacy

devices • Flexible architecture offering regulatory

compliance in all major regulatory domains while preserving interoperability

August 2004


Slide 5

doc.: IEEE 802.11-04/888r0

Submission

PHY Summary of TGn Sync Proposal

• Basic configuration delivers 243 Mbps using only two antennas– Follows historical trend of 5x for 802.11 (.11 .11b .11a/g)

• Higher optional PHY data rate rates (>600 Mbps) for future generation devices• MIMO evolution of 802.11 OFDM PHY with spatial division multiplexing of

spatial streams• Multiple antennas (2 mandatory, greater than 2 optional)• Preamble designed for seamless interoperability with legacy 802.11a/g• Wider bandwidth options with fully interoperable 20 MHz and 40 MHz* channel

capability• Support for licensed 10 MHz modes• Optional enhancements

– Advanced FEC coding techniques (RS, LDPC)– Transmit beamforming with negligible additional cost in receiving client device– 1/2 guard interval– Rate 7/8 coding

*Not required in regulatory domains where prohibited.

August 2004


Slide 6

doc.: IEEE 802.11-04/888r0

Submission

MAC Summary of TGn Sync Proposal

• Supports .11e• Frame aggregation, single and multiple* destinations• Bi-directional data flow• Feedback mechanisms that enhance rate adaptation• Protection mechanisms for seamless interoperability

and coexistence with legacy devices • Channel management (including receiver assisted

channel training protocol)• Power management

* Optional

August 2004


Slide 7

doc.: IEEE 802.11-04/888r0

Submission

PHY

August 2004


Slide 8

doc.: IEEE 802.11-04/888r0

Submission

Basic Tx Data Path• FEC coding

– Conventional K = 7 convolutional code• Rates: 1/2, 2/3 and 3/4• Supports legacy operation

– Optional LDPC/RS– Optional rate 7/8 code

• Spatial stream parsing• Frequency interleaving

– Block interleaver w/ QAM bit rotation (like 11a)– 20 MHz 16 columns freq. sep. = 3 subcarriers– 40 MHz 18 columns freq. sep. = 6 subcarriers

• QAM modulation– BPSK, QPSK, 16 QAM and 64 QAM

• Optional 1/2 guard interval

August 2004


Slide 9

doc.: IEEE 802.11-04/888r0

Submission

Basic Tx Data Path

FrequencyInterleaveracross 108data tones

ConstellationMapper

Insert GIwindow

Cha

nnel

Enco

der

spat

ial

pars

er

Punc

ture

r

iFFT128 tones in 40MHz114 populated tones

108 data tones6 pilot tones

RFBW ~ 36MHz


ConstellationMapper

Insert GIwindow



RFBW ~ 36MHz


ConstellationMapper

Insert GIwindow

Cha

nnel

Enco

der

spat

ial

pars

er

Punc

ture

r



RFBW ~ 36MHz


ConstellationMapper

Insert GIwindow



RFBW ~ 36MHz

2 antenna 20 MHz

2 antenna 40 MHz


ConstellationMapper

Insert GIwindow

Cha

nnel

Enco

der

spat

ial

pars

er

Punc

ture

r



RFBW ~ 17MHz


ConstellationMapper

Insert GIwindow



RFBW ~ 17MHz


ConstellationMapper

Insert GIwindow

Cha

nnel

Enco

der

spat

ial

pars

er

Punc

ture

r



RFBW ~ 17MHz


ConstellationMapper

Insert GIwindow



RFBW ~ 17MHz

August 2004


Slide 10

doc.: IEEE 802.11-04/888r0

Submission

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 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, 252 141.75, 283.5, 425.25, 567

+ Duplicate Format, BPSK R = ½ provides 6 Mbps for 40 MHz channels

* Optional short GI (0.4 sec) increases rates by 11.1% for maximum data rate of 640 Mbps

August 2004


Slide 11

doc.: IEEE 802.11-04/888r0

Submission

Throughput ComparisonModel D NLOS

0

20

40

60

80

100

120

140

160

180

200

220

240

260

0 5 10 15 20 25 30 35

SNR (dB)

Thro

ughp

ut (M

bps)

2x2-40 MHz4x4-20 MHz2x3-20 MHz2x2-20 MHz

Basic MIMO MCS set1000 byte packetsno impairments

Sweet Spot for 100Mbps top-of-MAC

2x2 – 40 MHz• Only 2 RF chains => Cost effective & low power• Lower SNRs @ throughput => Low cost RF• Throughput Overhead => Robust delivery of 100 Mbps

Standard 0.8 sec GI

August 2004


Slide 12

doc.: IEEE 802.11-04/888r0

Submission

PPDU FormatL-STF L-LTF L-

SIG HT-SIG HT LTF HT LTF Data

Legacy CompatiblePreamble

HT Part

HTSTF

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

August 2004


Slide 13

doc.: IEEE 802.11-04/888r0

Submission

Spoofing

• RATE and LENGTH PPDU length in OFDM symbols

• Spoofing– Spoofing means that the legacy RATE and LENGTH fields are

falsely encoded in order to determine a specified length– L-SIG RATE = 6 Mbps 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

August 2004


Slide 14

doc.: IEEE 802.11-04/888r0

Submission

Training Fields• Design priorities

– Backward compatibility with 802.11a/g– Robust performance– Cost effective implementation– Low overhead

These space-time diagrams apply to both 20 and 40 MHz channels

LTS12GI L SIGLTS2 HT SIG 1 HT SIG 2 LTS1 LTS2 DATA

DATA

DATA

DATA

DATA

DATA

DATA

DATA

DATA

STF L LTF L SIG HT SIG HT LTF Data

Antenna

1

2

3

LTS12GI LTS2

LTS12GI LTS2

L SIG HT SIG 1 HT SIG 2


HTSTS

HTSTS

HTSTS

LTS1 LTS2

LTS1 LTS2

LTS1 LTS2

LTS1 LTS2

LTS1 LTS2

HT LTFHT STF

August 2004


Slide 15

doc.: IEEE 802.11-04/888r0

Submission

Legacy Compatible PreambleCDD

LTS12GI L SIGLTS2 HT SIG 1 HT SIG 2

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

Antenna

1

2

3

LTS12GI LTS2

LTS12GI LTS2



HTSTS

HTSTS

HTSTS

LTS12GI L SIGLTS2 HT SIG 1 HT SIG 2

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

Antenna

1

2

3

HTSTS

HTSTS

HTSTS

or single antenna

The L-STF, L-LTF, L-SIG and HT-SIG are transmitted as a single spatial stream. This may be either transmitted on all Tx antennas via a method such as Cyclic Delay Diversity (CDD), or on a single antenna. These are implementation options.

Requirement: These fields must be transmitted in an omni-directional mode that can be demodulated by legacy receivers.

August 2004


Slide 16

doc.: IEEE 802.11-04/888r0

Submission

HT Training Fields

• HT-STF– Used for 2nd AGC

• HT-LTF– Used for MIMO channel estimation– Additional frequency or time alignment

• Tone interleaving of spatial streams

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

August 2004


Slide 17

doc.: IEEE 802.11-04/888r0

Submission

40 MHz PPDU Format

• Duplicate format preamble– Provides interoperability with 20 MHz legacy STAs– Data, pilot and training tones in each 20 MHz subchannel are identical to

corresponding 20 MHz format– 90 deg phase shift on upper sub-channel controls PAPR

• HT part– 108 data tones + 6 pilots– 3 center nulls (not shown)

DuplicateL-STF(90 deg)

DuplicateL-STF

DuplicateL-LTF(90 deg)

DuplicateL-LTF

Dup.L-

SIG(90 deg)

Dup.L-

SIG

DuplicateHT-SIG(90 deg)

DuplicateHT-SIG

HT

STS

HT-LTF1 HT-LTF2 Data Data

August 2004


Slide 18

doc.: IEEE 802.11-04/888r0

Submission

40/20 MHz Interoperability• 20 MHz PPDU 40 MHz receiver

– Combine modulation symbols from upper & lower sub-channels– 20 MHz PPDU in lower sub-channel

• Zero combining weights in upper subchannel• No loss in performance relative to a 20 MHz receiver

– Use differential sub-channel energy to detect 20 vs. 40 MHz signals

• 40 MHz PPDU 20 MHz receiver– One sub-channel is sufficient to decode the L-SIG– Detects only half of the 40 MHz signal

3 dB performance penalty for 20 MHz clients

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

August 2004


Slide 19

doc.: IEEE 802.11-04/888r0

Submission

Transmit Beamforming• Basic Beamforming

– Cost, complexity, and power consumption contained in the AP• Enterprise AP, media server AP, set-top box, or desktop PC

– Very low overhead for BF receive only client• Low client cost, essentially zero overhead• Low power consumption – battery operated

– Basic MCS set– Channel sounding PPDU provides capability to estimate the channel from all

Tx antennas– Receiver does not need to know the beamforming specifics at the transmitter– Simple packet exchange for calibration

• Optional Advanced Beamforming (ABF)– Extended MCS Set

• Provides independent modulation/coding across spatial streams– Support for unequal spatial stream power loading– Support for bi-directional beamforming

August 2004


Slide 20

doc.: IEEE 802.11-04/888r0

Submission

ABF Throughput Comparison20MHz, Model D NLOS

0

20

40

60

80

100

120

140

160

0 5 10 15 20 25 30 35

SNR (dB)

Thro

ughp

ut (M

bps)

2x2 - Open Loop - Basic MCS2x3 - Open Loop- Basic MCS2x2 - ABF - Extended MCS3x2 - ABF - Extended MCS4x2 - ABF - Extended MCS

No Impairments1000 byte packets

4 Tx AP => 2 Rx Client ~10 dB gain over Basic 2x2! => cost effective server-client

August 2004


Slide 21

doc.: IEEE 802.11-04/888r0

Submission

Optional Advanced Coding Modes

• Low Density Parity Check (LDPC)– Superior performance at high code rates (7/8)

• Reed-Solomon (RS)– Outer code concatenated with inner

convolutional code– Very low cost, mature technology

August 2004


Slide 22

doc.: IEEE 802.11-04/888r0

Submission

Adv. Coding Throughput Comparison2x2, 20MHz, Model D NLOS

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

Conv. + RS

Basic MIMO MCS SetNo Impairments1000 byte packets

LDPC yields a 2x2 20 MHz high throughput solution at reasonable SNR!

August 2004


Slide 23

doc.: IEEE 802.11-04/888r0

Submission

MAC

August 2004


Slide 24

doc.: IEEE 802.11-04/888r0

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

August 2004


Slide 25

doc.: IEEE 802.11-04/888r0

Submission

New MAC Features• Aggregation Format• Aggregation Exchanges

– Protocol for training– Protocol for reverse direction data– Single and multiple responder

• Header Compression• Protection Mechanisms• Coexistence & Channel Management• MIMO Power Management

August 2004


Slide 26

doc.: IEEE 802.11-04/888r0

Submission

Aggregation FramingM

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 Framing is a purely-MAC function

(PHY has no knowledge of MPDU boundaries)

August 2004


Slide 27

doc.: IEEE 802.11-04/888r0

Submission

Aggregate Exchange Sequences

• MPDU or frame exchange sequences now extended to aggregate exchange sequences in which groups of frames are exchanged “at a time”– Allows effective use of Aggregate Feature– Allows control, data and acknowledgement 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)

August 2004


Slide 28

doc.: IEEE 802.11-04/888r0

Submission

Dat

a M

PD

UA

ggP

PD

UD

ata

MP

DU

BA

R M

PD

U

Dat

a M

PD

U

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

Non

-agg

PP

DU

Blo

ck A

ck

Bas

ic ra

teno

n-ag

gIA

C M

PD

U(R

TS)

Bas

ic ra

teno

n-ag

gR

AC

MP

DU

(CTS

)

Dat

a M

PD

U

Agg

PP

DU

Dat

a M

PD

UB

AR

MP

DU

Dat

a M

PD

U

Non

-agg

PP

DU

Blo

ck A

ck

Dat

a M

PD

UD

ata

MP

DU

Dat

a M

PD

U

Dat

a M

PD

UD

ata

MP

DU

Dat

a M

PD

U

Block AckProtocol

IAC/RACProtocol

Basic Aggregate Exchange

August 2004


Slide 29

doc.: IEEE 802.11-04/888r0

Submission

Agg

PP

DU

BA

R M

PD

U

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

g

IAC

MP

DU

(RTS

+M

RQ

+RD

L)

Bas

ic ra

teno

n-ag

g

RA

C M

PD

U(C

TS+M

FB+

MR

Q+R

DR

)

Dat

a M

PD

U

Agg

PP

DU

Dat

a M

PD

UB

AR

MP

DU

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+M

FB)

Reverse DirectionProtocol

BA

R M

PD

U

Dat

a M

PD

UD

ata

MP

DU

IAC

MP

DU

RD

GD

urat

ion

Reverse Direction Protocol

August 2004


Slide 30

doc.: IEEE 802.11-04/888r0

Submission

Training Protocol

August 2004


Slide 31

doc.: IEEE 802.11-04/888r0

Submission

Periodic Multi-Receiver Aggregation

August 2004


Slide 32

doc.: IEEE 802.11-04/888r0

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

August 2004


Slide 33

doc.: IEEE 802.11-04/888r0

Submission

Pairwise Spoofing Protection• Protects pairs of PPDUs (current and following)• Very low overhead, suitable for short exchanges• Places Legacy devices into receiving mode for spoofed duration• Spoofing is interpreted by HT devices as a NAV setting

August 2004


Slide 34

doc.: IEEE 802.11-04/888r0

Submission

Operating Mode Selection• BSS operating mode controls the use of protection

mechanisms and 40/20 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

August 2004


Slide 35

doc.: IEEE 802.11-04/888r0

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

August 2004


Slide 36

doc.: IEEE 802.11-04/888r0

Submission

CC 28/29 PerformanceGoodput vs Range, Channels B & D, 20 & 40 MHz

0

50

100

150

200

250

0 20 40 60 80 100

Range (m)

Goo

dput

(Mbp

s)

B/20D/20B/40D/40

Mandatory features only

August 2004


Slide 37

doc.: IEEE 802.11-04/888r0

Submission

MAC Selected CC PerformanceCC# Name Result HCCA

2x2x20 2x2x40CC3 List of goodput results for usage

models 1, 4 and 6.SS1 (Mbps) 55.2 76.8

SS4 45.1 74.1

SS6 44.9 62.1

CC18 HT Usage Models Supported (non QoS)

SS1(Mbps/ratio)

2.76/0.09 24.4/0.8

SS4 36.0/0.07 65.0/0.14

SS6 0.1/0.005 17.24/0.86

CC19 HT Usage Models Supported (QoS)

SS1 17/17 17/17

SS4 18/18 18/18

SS6 39/39 39/39

CC58 HT Spectral Efficiency bps/Hz 5.4 6.075

doc.: ieee 802.11-04/888r0 submission august 2004 aon mujtaba, agere systems, et alslide 1 tgn sync...

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