beyond 802.11n · 4 gigabit wi-fi (ieee 802.11ac) goal a maximum multi-sta throughput of at least...

Beyond 802.11n: 무선랜 최신 기술 및 표준화 동향

LG전자

차세대통신 연구소

석용호 책임연구원

([email protected])

1

Outline

Wi-Fi network: state of the art

Gigabit Wi-Fi (IEEE 802.11ac/ad)

Extended Wi-Fi (IEEE 802.11af/ah)

Future Wi-Fi Technology and Application

KRnet 2013

IEEE 802.11a-to-z (completed)

IEEE 802.11aa (completed)

IEEE 802.11ac

IEEE 802.11ad (completed)

IEEE 802.11ae (completed)

IEEE 802.11af

IEEE 802.11ah

IEEE 802.11ai

IEEE 802.11aj

IEEE 802.11ak

IEEE 802.11aq

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KRnet 2013


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PHY

MAC

Study groups

Published Standard

WG Letter Ballot

802.11-2012

802.11aa Video Transport

802.11ac VHT 5GHz

TG without Approved draft

Discussion Topics

802.11af TVWS

Smart Grid 802.11ai

FILS

802.11 ah WNG

802.11ae QoS Mgt Frames

802.11ad VHT 60 GHz

802.11aq PAD

802.11aj

802.11-2015

802.11ak GLK

High Efficiency WLAN

KRnet 2013

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Gigabit Wi-Fi (IEEE 802.11ac)

Goal A maximum multi-STA throughput of at least 1Gbps and a maximum single link

throughput of at least 500Mbps

Technology Comparison between 802.11a/n/ac 802.11a 802.11n 802.11ac

Frequency band 5 GHz only 2.4 GHz/5 GHz 5 GHz only

Channel Bandwidth 20 MHz 20 MHZ/40 MHz 20 MHz/40 MHz/ 80 MHz/160 MHz/80+80 MHz

Number of Spatial Stream 1 1~4 1~8

Peak PHY Rate 54 Mbps 600 Mbps 6.9 Gbps

Key Technology OFDM MIMO MU-MIMO

KRnet 2013


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VHTL6⇒

IEEE802.11ac

VHT60⇒

IEEE802.11ad

VHT SG focus:

- Throughput : Maximum

channel bandwidth ~ 80 MHz and

Peak Data Rate at least 2 Gbps

- Range: Provide better/higher

data rates at longer range than

what is available with TGn

-Power: Power consumption for

traffic upload or download should

not be more than half of what it

would be when using TGn power

save features and at the same

range

Discussion on Propatation

between 60GHz and 5GHz:

- Pathloss

- PA Power

- Blockage effect

- etc

Conclusion:

60 GHz frequency band may

not be suitable for applications

that require similar range

requirements and applications

as 802.11a/b/g/n systems.

Split!!

KRnet 2013

6

Gigabit Wi-Fi (IEEE 802.11ac) Cable /

DSL

Modem

WLAN

Bridge

IPTV Box

e.g. Roku

Kids

Surveillance

Monitor

Entertainment PC

Cloud

Back Up

Drive

Car Video

Content

Server

NAS

Drive

DTV1

DTV2

Car Parked

in Carport

Kids Room

Surveillance Video

Cam

KRnet 2013

http://images.google.com/imgres?imgurl=http://www.engadget.com/media/2008/04/ec.son.dmxnv1.jpg&imgrefurl=http://www.engadgethd.com/2008/04/23/sonys-dmx-nv1-bravia-internet-video-link-now-available/&h=336&w=164&sz=10&hl=en&start=52&um=1&tbnid=LdfY8uTxe0prnM:&tbnh=119&tbnw=58&prev=/images?q=sony+Internet+Video+Link+photo&start=42&ndsp=21&um=1&hl=en&sa=N

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11n 11ac

SU-MIMO Up-to 4 spatial streams. Up-to 8 spatial streams

MU-MIMO Not defined. Defined in AP-to-Non_AP STA:

- Max # of Nss per user in MU: 4

- Max # of MU users: 4

- Max # of Nss over all users in MU: 8

Bandwidth Maximum 40MHz Maximum 160MHz

- Mandatory: 20/40/80MHz

- Optional: 160MHz, 80+80MHz

MCS BPSK, QPSK, 64QAM BPSK, QPSK, 64QAM,

256 QAM (optional)

Max

Throughput 600 Mbps 6933.3 Mbps 11.5

times

Higher MIMO, Wider bandwidth, and Higher MCS are introduced

KRnet 2013

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Gigabit Wi-Fi (IEEE 802.11ad)

Goal A maximum single link throughput of at least 1Gbps

Technology Comparison between 802.11ac/ad

802.11ac 802.11ad

Frequency band 5 GHz only 60 GHz only

Channel Bandwidth 20 MHz/40 MHz/ 80 MHz/160 MHz/80+80 MHz

2.16 GHz

Number of Spatial Stream 1~8 1

Peak PHY Rate 6.9 Gbps 6.7 Gbps

Key Technology MU-MIMO Directional antenna

KRnet 2013

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clip/movie

Rapid Upload / Download

Wireless Display WLAN

~1Gbps Range <3-8m, LOS, specific placement Latency ~ ok

1080p today (~3Gbps) Max rate + compression Range 5-10m, NLOS Latency < 15ms (gaming)

Max Avail Bandwidth Efficient handling of Mixed types Range 5-10m, ~NLOS Latency < 30ms

KRnet 2013

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Usages are peer-to-peer (ad-hoc) in nature

No device is dedicated for a particular function

All devices in the network perform the role of a content consumer or content creator or both

Access to WLAN infrastructure may not be required in all cases

In order to achieve higher throughputs directional antennas are key to any design

This can be achieved through antenna arrays which helps to steer the beam in one direction or through sectorized antennas

Directional communication: efficient, high rate

Omni communication: expensive, much lower rate or shorter range

Sector

sweeping

KRnet 2013

11

Extended Wi-Fi (IEEE 802.11af)

Goal Define modifications to both the 802.11 physical layers (PHY) and the 802.11

Medium Access Control Layer (MAC), to meet the legal requirements for channel access and coexistence in the TV White Space

Technology Comparison between 802.11ac/af

802.11ac 802.11af

Frequency band 5 GHz only TV White Space only

(e.g., 54~72, 76~88, 174~216 470~698MHz)

Channel Bandwidth 20 MHz/40 MHz/ 80 MHz/160 MHz/80+80 MHz

6 MHz/12 MHz/24 MHz/6+6 MHz/12+12 MHz (US, KR)

7 MHz/14 MHz/28 MHz/7+7 MHz/14+14 MHz (JP)

8 MHz/16 MHz/32 MHz/8+8 MHz/16+16 MHz (EU)

Number of Spatial Stream 1~8 4

Peak PHY Rate 6.9 Gbps 384 Mbps (US, KR, JP)

568.9 Mbps (EU)

Service Coverage <250m < 1Km

KRnet 2013


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Cellular Traffic Offloading A/V Streaming throughout entire household

Key Requirements:

• Protection to the incumbent users, to meet legal requirements

• Appropriate data rates to provide good user experience with extended coverage area

KRnet 2013


In November 2008, the FCC approved the use of White Spaces by unlicensed devices, which introduced up to a total of 180 MHz available for portable operation.

The final rules from the FCC were announced in late 2010.

Similarly Ofcom also announced white space rule for UK in 2012.

Regulators around the world are interested in the use of geo-location database techniques to enable the use of White Spaces.

IEEE 802.11 TGaf is currently working on the standard wireless LAN operation on White Spaces. General rule for White Space is “Devices should transmit after querying a

database”

13 KRnet 2013

White Space Map (WSM)

TV CH 40 TV CH 41 TV CH 42 TV CH 43 TV CH 44 TV CH 45 TV CH 46

5 MHz

WLAN

Channel

10 MHz

WLAN

Channel

10 MHz

WLAN

Channel

RLS

(or DB)AP

STA

Enabling Signal

Enablement Request

Enablement Response with WSM

6 MHz bandwidth

TV Channel

WLAN Channel

(5MHz, 10MHz, 20MHz or 40MHz)


KRnet 2013


The PHY for one TVWS channel (6MHz, 7MHz or 8MHz) is based on the 40MHz VHT PHY (128FFT).

15 KRnet 2013

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Extended Wi-Fi (IEEE 802.11ah)

Goal Defines enhancements to the IEEE 802.11 Medium Access Control (MAC) to

support an Orthogonal Frequency Division Multiplexing (OFDM) Physical layer (PHY) operating in the license-exempt bands below 1 GHz, e.g., 868-868.6 MHz (Europe), 950 MHz -958 MHz (Japan), 314-316 MHz, 430-434 MHz, 470-510 MHz, and 779-787 MHz (China), 917 – 923.5 MHz (Korea) and 902-928 MHz (USA)

Technology Comparison between 802.11af/ah

802.11af 802.11ah

Frequency band TV White Space only

(e.g., 54~72, 76~88, 174~216 470~698MHz)

Below 1 GHz excluding the TV White Space bands

(e.g., 902~928MHz)

Channel Bandwidth 6 MHz/12 MHz/24 MHz/6+6 MHz/12+12 MHz (US, KR)

7 MHz/14 MHz/28 MHz/7+7 MHz/14+14 MHz (JP)

8 MHz/16 MHz/32 MHz/8+8 MHz/16+16 MHz (EU)

1/2/4/8/16 MHz

Number of Spatial Stream 4 4

Peak PHY Rate 384 Mbps (US, KR, JP)

568.9 Mbps (EU)

346.6 Mbps

Service Coverage < 1Km < 1Km

Supported maximum STAs 2007 About 8,000

KRnet 2013


Use Cases: Smart Grid – Meter to Pole

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Wide Area

Gas

Meter

Water

Meter

Power

Meter

Distributed

Automation

Device

Neighbor Area Home Area

Wireless communication link

Wired communication link

Proposed infrastructure

Data Collector

& Control

IEEE 802.11ah

AP

Distributed

Automation

Device

KRnet 2013


Channelization

Data Rates

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Country Frequency (MHz) BW # of 1MHz Ch # of 2MHz Ch # of 4MHz Ch

US 902 – 928 26MHz 26 13 6

EU 863 – 868.6 5.6MHz 5 2 1

Japan 915.9 - 928.1 12.2MHz 11 0 0

Korea 917 – 923.5 6.5MHz 6 3 1

BW in MHz Range of data rates supported for 1ss Range of data rates supported for 2ss

1 150 kbps to 4Mbps 600 kbps to 8 Mbps

2 650 kbps to 7.8 Mbps 1.3 Mbps to 15.6 Mbps

4 1.35 Mbps to 18 Mbps 2.7 Mbps to 36 Mbps



KRnet 2013


Short frame The general structure for short frame is similar to 11n green field preamble

Long frame The general structure for long frame is similar to 11ac preamble

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STF LTF1 SIG DATA

(2 symbols) (2 symbols ) (2 symbols)

(1 symbol each)

DGI LTS LTS

LTF2 … LTF_NLTF QBPSK

STF LTF1 SIGA DATA Field

(2 symbols) (2 symbols

as 11n GF)

(2 symbols)

(1 symbol each)

DGI LTS LTS

D-LTF1 … D-LTF_NLTF D-STF SIGB

(1 symbol)

“Omni” Portion Data Portion

KRnet 2013


Support 1MHz mode PHY (32 FFT) and 2x repetition as the lowest rate

Preamble format Robust and simple packet detection for up-to 2x repetition

Accurate channel estimation which enables repetition mode to provide ~3 dB gain over MCS0

Simple differentiation from 2MHz mode during LTFs and through QBPSK rotation of 2MHz SIG

STF1

(Same periodicity as 2 MHz,

3 dB power boost for rep-2)

Repetition coded SIG

Field

LTF1

(Orthogonal in freq domain to

2MHz LTF)

Repetition or non-

repetition encoded Data

4 symbols 5-6 symbols4 symbols=160 ms

LTF2 to LTFN

(for MIMO)

Preamble Format for 1 MHz

DGI LTS LTS GI LTS GI LTS

20 KRnet 2013


11ah use case includes a large outdoor network For an outdoor smart grid network, the number of STAs can be 2007+

The STAs can be grouped into AID groups/pages

STAs supporting different use cases can be easily grouped into different Pages Sensor stations (infrequent traffics) Page 1

Offloading stations (frequent traffics) Page 2

21 KRnet 2013


Too many bits set in the TIM element may trigger too many PS-Poll/trigger frame transmissions right after the beacon frame within a short period of time Increase collisions between the hidden nodes

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STA1 STA2

AP STA2’s transmission range STA1’s transmission range

TIM (n bits set to 1)

Beacon interval

STA1

STA2

STAn

…

PS-Poll/trigger frame

n transmissions within a short period of time

KRnet 2013


Channel Access Procedure A Restricted Access Window (RAW) is divided in time slots.

STA wakes up at TBTT and it listens to a Beacon frame that indicates the slot duration for each Restricted Access Window (RAW).

STA determines its channel access slot assigned by AP.

STA may sleep before its channel access slot.

STA shall start to access the channel at the slot boundary of its channel access slot based on EDCA.

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Beacon Interval

Restricted Access Window (RAW)

Slot

Boundary Slot

Boundary

Slot

Boundary

Slot

Boundary Slot

Boundary

Slot

Boundary

Slot duration

KRnet 2013


Future Wi-Fi Technology Gigabit Wi-Fi

Wi-Fi VHT5G : certification program of IEEE 802.11ac

Wi-Fi 60G : certification program of IEEE 802.11ad

Extended Wi-Fi

Wi-Fi TVWS (TV Whitespace) : certification program of IEEE 802.11af

Low Power Wi-Fi

Wi-Fi NPS (Network Power Save) : certification program of IEEE 802.11v

Wi-Fi Power Conservation

24 KRnet 2013


Future Wi-Fi Technology New High Efficiency WLAN (HEW) Study Group for enhancing 802.11 PHY and

MAC in 2.4 and 5GHz with a focus on:

Improving spectrum efficiency and area throughput

Improving real world performance in indoor and outdoor deployments

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Scenario Issues

1. Large no. of

STAs

• weak flexibility in use of resources (time, frequency, space) to multiplex users efficiently

• high collisions and weak MAC efficiency with many STAs, especially with mixed traffic

and legacy devices

2. Large no. of

APs

• limited spatial capacity with OBSS due to spatial protection, interference and lack of

coordination with neighboring APs

• lack of framework for consistent and flexible admission control, load balancing and

fairness

• weak airtime occupation ratio for management vs data

3. Outdoor • weak uplink and high interference, weak non-LOS reliability

• weak robustness to higher delay spreads and Doppler

KRnet 2013


Future Wi-Fi Technology Wide bandwidth channels desired to support high throughput requirements

At the same time, large number non-overlapping channels desired to support high QoS requirements

Current UNII spectrum allows only

Six 80 MHz channels

Two 160 MHz channels

Additional unlicensed use of 5.35-5.47 GHz and 5.85-5.925 GHz would allow

Nine 80 MHz channels

Four 160 MHz channels

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20 MHz

40 MHz 80 MHz

160 MHz

UNII-1 UNII-2 UNII-2 UNII-3

5250

MHz

5350

MHz

5470

MHz

5725

MHz

NEW 5825

MHz

5925

MHz

NEW

Currently available

channels

New channels

KRnet 2013


Future Wi-Fi Application Wi-Fi Passpoint : certification program of IEEE 802.11u

Wi-Fi Display

Wi-Fi Display 2.0 has been discussed.

Wi-Fi Serial BUS

Wi-Fi Docking

Wi-Fi NAN (Neighbor Awareness Network)

27 KRnet 2013

Conclusion

1st Generation (1997) IEEE 802.11 (2Mbps)

2nd Generation (1999) IEEE 802.11b (11Mbps)

3rd Generation (2002) IEEE 802.11g/a (54Mbps)

4th Generation (2007) IEEE 802.11n (Up to 600Mbps, Most common is 150Mbps)

5th Generation (2012) IEEE 802.11ac (Up to 6.9Gbps, First solution is 1.3Gbps)

6th Generation (????) IEEE 802.11af, IEEE 802.11ah, High Efficiency WLAN ?

28 KRnet 2013

References

https://mentor.ieee.org/802.11/dcn/13/11-13-0167-01-0000-802-11-opening-report-snapshots-orlando-march-2013.pptx

https://mentor.ieee.org/802.11/dcn/13/11-13-0339-10-0wng-high-efficiency-wlan-straw-poll.ppt

https://mentor.ieee.org/802.11/dcn/13/11-13-0331-05-0wng-high-efficiency-wlan.ppt

https://mentor.ieee.org/802.11/dcn/13/11-13-0657-01-0hew-hew-sg-usage-models-and-requirements-liaison-with-wfa.ppt

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beyond 802.11n · 4 gigabit wi-fi (ieee 802.11ac) goal a maximum multi-sta throughput of at least...

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