introduction of tgnsync 802 11n proposal n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Introduction of TGnSync 802.11n proposal PowerPoint Presentation
Download Presentation
Introduction of TGnSync 802.11n proposal

Loading in 2 Seconds...

play fullscreen
1 / 30

Introduction of TGnSync 802.11n proposal - PowerPoint PPT Presentation


  • 115 Views
  • Uploaded on

Introduction of TGnSync 802.11n proposal. Speaker:Zih-Yin Ding Professor: Tzi-Dar Chiueh September 27 th , 2004. Outline. Introduction of 802.11n Motivation Functional Requirement Primary Schedule Milestones Introduction of the TGnSync 802.11n Proposal PHY Enhancement Techniques

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Introduction of TGnSync 802.11n proposal' - rusti


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
introduction of tgnsync 802 11n proposal

Introduction of TGnSync 802.11n proposal

Speaker:Zih-Yin Ding

Professor: Tzi-Dar Chiueh

September 27th, 2004

outline
Outline
  • Introduction of 802.11n
    • Motivation
    • Functional Requirement
    • PrimarySchedule Milestones
  • Introduction of the TGnSync 802.11n Proposal
    • PHY Enhancement Techniques
    • Operation Modes
    • Packet format
  • Conclusion
  • Reference
motivation
Motivation
  • High throughput drives the demand for 802.11n

[3]

project authorization request par
Project Authorization Request (PAR)
  • 802.11n PAR scope:
    • To define standardized modifications to both the 802.11 physical layers (PHY) and the 802.11 Medium Access Control Layer (MAC) so that modes of operation can be enabled that are capable of much higher throughputs, with a maximum throughput of at least 100Mbps, as measured at the MAC data service access point (SAP).
primary schedule milestones
PrimarySchedule Milestones

Issue First Letter Ballot on Draft 1.0 July 2005

Issue First Sponsor Ballot Mar 2006

Complete Sponsor ballot

- accepted by ExCom Nov 2006

Publish Mar 2007

tgnsync
TGnSync
  • Some of TGnSync members include:

Agere Systems Inc.

Atheros Communications Inc.

Cisco Systems, Inc.

Intel Corporation

Marvell Semiconductor, Inc.

Nokia Corporation

Nortel Networks Corporation

Panasonic (Matsushita Electric Industrial Co. Ltd.)

Royal Philips Electronics N.V.

Samsung Electronics Co. Ltd.

SANYO Electric Co. Ltd.

Sony Corporation

Toshiba Corporation

phy enhancement techniques 1 2
PHY Enhancement Techniques (1/2)
  • High Throughput Enhancement involved
    • Spatial Multiplexing using MIMO
    • Increasing the channel bandwidth
    • Reducing the guard interval overhead
    • Increasing the coding rate
phy enhancement techniques 2 2
PHY Enhancement Techniques (2/2)
  • Link Robustness Enhancement Techniques
    • Keep the client low cost and low power
    • Transmitter beamforming
    • Advanced transmitter beamforming techniques
      • Water-filling concept
      • Unequal power ratios and different choice of modulation-coding schemes on various spatial streams
    • Advanced channel coding
      • Low density parity code (LDPC)
      • CC+RS
phy features
PHY Features
  • MIMO evolution of 802.11 OFDM PHY – up to 4 spatial streams
  • 20 and 40MHz channels
  • 2x2 architecture – 140Mbps in 20MHz and 315Mbps in 40MHz
  • Preamble allows seamless interoperability with legacy 802.11a/g
  • Optional enhancements
    • Transmit beamforming with negligible overhead at the client
    • Advanced channel coding techniques (RS, LDPC)
    • 1/2 guard interval (i.e. 400ns)
    • 7/8 coding rate
mimo transmission modes
MIMO Transmission Modes
  • Basic MIMO Mode (Mandatory)
    • Nss=NTX
  • Basic MIMO with TX Beamforming (optional)

: BF-MIMO

    • Nss<= NTX
    • All spatial stream have identical MCS and power level
  • Advanced MIMO with TX Beamforming (optional): ABF-MIMO
    • Nss<= NTX
    • MCS and power level in each spatial stream can be different
tx arch spatial division multiplexing e g 2 spatial streams with 2 tx antennas mandatory
TX Arch: Spatial Division Multiplexinge.g.2 Spatial streams with 2 TX antennas (mandatory)

iFFT

Modulator

Preamble

insert

GI

window

symbols

Pilots

Frequency

Interleaver

Constellation

Mapper

Scrambled

MPDU

iFFT

Modulator

Preamble

Channel Encoder

Puncturer

Spatial parser

insert

GI

window

symbols

Pilots

Frequency

Interleaver

Constellation

Mapper

tx arch spatial division multiplexing e g 2 spatial streams with 3 tx antennas optional
TX Arch: Spatial Division Multiplexinge.g.2 Spatial streams with 3 TX antennas (optional)

HT LTF

iFFT

Mod.

insert

GI

window

Pilots

Frequency

Interleaver

Constellation

Mapper

Spatial Steering (TX Beamforming), or

Orthogonal Spatial Spreading with Cyclical Delay

iFFT

Mod.

insert

GI

window

HT LTF

Scrambled

MPDU

Channel Encoder

Puncturer

Spatial Parser

Pilots

iFFT

Mod.

insert

GI

Frequency

Interleaver

Constellation

Mapper

window

band design for 20 and 40 mh z
Band Design for 20 and 40 MHz
  • 20 MHz:
  • Identical to 802.11a
  • 64 point FFT
  • 48 data tones
  • 4 pilot tones

-26

-21

-7

-1

+1

+7

+21

+26

Tone Fill in the Guard Band

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

-25

-11

+11

+25

+53

-53

+32

-2

+2

-64

-58

-32

-6

+6

+58

+63

Legacy 20 MHz in

Lower Sub-Channel

Legacy 20 MHz in

Upper Sub-Channel

motivation for 40mhz channelization

2x2-40 MHz

4x4-20 MHz

2x3-20 MHz w/ short GI

2x2-20 MHz w/ short GI

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

260

240

220

200

Sweet spot for 100Mbps top-of-MAC

180

160

140

Over the Air Throughput (Mbps)

120

100

80

Basic MIMO MCS set

No impairments

1000 byte packets

TGn channel model B

60

40

20

0

0

5

10

15

20

25

30

35

SNR (dB)

basic mcs set
Basic MCS Set

* Optional short GI (400ns) increases rates by 11.1%

packet format 2 spatial stream
Packet format (2 spatial stream)

L-STF

L-LTF

L-SIG

HT-SIG

HT-DATA

HT

LTF-2

ANT_1

HT

STF

HT

LTF-1

20MHz

Legacy Compatible Preamble

HT-specific Preamble

Legend

L- Legacy

HT- High Throughput

STF Short Training Field

LTF Long Training Field

SIG Signal Field

  • The HT-SIG include Length, MCS, Advanced options and CRC(cyclic redundancy check)
ht p acket detection
HT Packet Detection

L-STF

L-LTF

L-SIG

HT-SIG

  • Auto-detection scheme on HT-SIG
    • Q-BPSK modulation
    • Invert the polarity of the pilot tones

or

Legacy

DATA

L-STF

L-LTF

L-SIG

Legacy Compatible Preamble

BPSK

-1

+1

Q-BPSK

+1

-1

ht training fields
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
    • The number of HT-LTF= The number of spatial stream
conclusion
Conclusion
  • The proposal proposed by TGnSync is introduced.
  • From this proposal, we can find some techniques that may be introduced in High Through WLAN are
    • MIMO technique, wider channel bandwidth, reduced guard interval, increased coding rate and advanced coding
reference
Reference

[1] TGnSync Website: http://www.tgnsync.org

[2] TGnSync Present slide- DCN:11-04-0888-02-000n

[3] http:// snrc.stanford.edu/events/industry- seminar/spring03/slides/taekon.pdf

20 40 mhz interoperability
20/40 MHz Interoperability
  • 20 MHz PPDU into a 40 MHz receiver
    • The active 20 MHz sub-channel is detected using energy measurement of the two sub-channels
    • Inactive tones at the FFT output (i.e. 64 out of 128) are not used
  • 40 MHz PPDU into a20 MHz receiver
    • One 20 MHz sub-channel is sufficient to decode the L-SIG and the HT-SIG
advanced technique
Advanced technique
  • Beamforming
    • To increase the antenna gain in the direction of an intended receiver
    • One method to calculate V involves SVD of the channel transfer matrix H
    • Channel state information is needed
    • Reciprocity is assumed
    • RF calibration is needed
mandatory v s optional
Mandatory v.s. optional
  • Mandatory: 20MHz, spatial multiplexing
  • Optional: Beamforming, 20MHz or 40MHz channel bandwidth, LDPC
packet format in 20mhz
Packet format in 20MHz

HT

STF

HT

LTF-1

HT

LTF-2

L-STF

L-LTF

L-SIG

HT-SIG

HT-DATA

ANT_1

20MHz

L-STF

L-LTF

L-SIG

HT-SIG

HT-DATA

ANT_2

20MHz

Legacy Compatible Preamble

HT-specific Preamble

Legend

L- Legacy

HT- High Throughput

STF Short Training Field

LTF Long Training Field

SIG Signal Field

overview of key mandatory features
Overview of key mandatory features
  • The WWiSE proposal’s mandatory modes are:
    • 2 transmit antennas
    • 20 MHz operation
    • 135 Mbps maximum PHY rate
    • 2x1 transmit diversity modes, 20 MHz
    • Mixed mode preambles enabling on-the-air legacy compatibility
    • Efficient greenfield preambles – no increase in length over legacy
    • Enhanced efficiency MAC mechanisms
    • All components based on enhancement of existing COFDM PHY
overview of key optional features
Overview of key optional features
  • The WWiSE proposal’s optional modes are:
    • 3 and 4 transmit antennas
    • 40 MHz operation
    • Up to 540 Mbps PHY rate
    • 2x1, 3x2, 4x2, 4x3 transmit diversity modes
    • Advanced coding: Rate-compatible LDPC code