WiFi 6 - FHI

WiFi 6Wifi6 is coming, but what will change?

Sjoerd Hakstege – van Eekhout

Phoenix Contact B.V.

Wifi Alliance StandardsNew naming for the different Wifi versions

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Wifi Name IEEE Standard Data-Rate

Wifi 6 802.11ax (Wave1&2) 4800+ Mbps

Wifi 5 802.11ac (Wave1&2) 1300+ Mbps

Wifi 4 802.11n 450 Mbps

Wifi 3 802.11g 54 Mbps

Wifi 2 802.11a 11 Mbps

Wifi 1 802.11b 54 Mbps

AdvantagesWiFi 6 / IEEE 802.11ax

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More devices

Higher efficiency

Higher security

Higher Range

Longer battery life

Higher data throughputBetter QoS

Higher Relaibility

Lower Latency

Higher density

• Orthogonal frequency-division multiple access (OFDMA) uplink and downlink (UL/DL)

• Longer orthogonal frequency-domain multiplexing (OFDM) symbol

• Multi-user multiple-input multiple-output (Mu-MiMo) 8×8 and UL/DL

• Spatial reuse, also referred to as BSS Coloring

• Target Wake Time (TWT) — power saving

• 1024 quadrature amplitude modulation (1024-QAM)

• New PHY headers

• Enhanced outdoor robustness

• 5 GHz and 2.4 GHz support

802.11ax focuses on nine main enhancements

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Wireless ApplicationsNext Wireless LAN Generation

Smart devicesMoving Systems

Mobile robots

IIoT-devicesVideo Surveillance

ShuttleM2M

AGV

Tablets

WLAN AX / WiFi6: 3 main advantages for industrial applications

Faster, optimized capacity, IoT ready

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ODFMA MU-MIMO BSS Coloring

Long OFDM Symbol

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20 MHz / 64 = 312,5 kHzSymbol duration 3.2 usec

20 MHz / 256 = 78,125 kHzSymbol duration 12.8 usec

64 Subcarrier 256 Subcarrier

4xn/ac ax

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Long OFDM Symbol

WLAN AX / WiFi6: 3 main advantages for industrial applications

Faster, optimized capacity, IoT ready

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ODFMA MU-MIMO BSS Coloring

WLAN AX / WiFi 6 advantages

Faster, optimized capacity, IoT ready

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OFDMA

Application example

OFDMA

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OFDM - Orthogonal Frequency Division Multiplexing (802.11n/ac)

OFDMA

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time

20

Mh

z

Stat

ion

1

Stat

ion

2

Stat

ion

3

Stat

ion

4

Stat

ion

5

Stat

ion

6

Stat

ion

7

Stat

ion

8

Stat

ion

9

Stat

ion

1

Stat

ion

2

Stat

ion

3

Stat

ion

4

64 Sub

carrier

OFDMA - Orthogonal Frequency Division Multiple Access (802.11ax)

OFDMA

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time

20 MH

z

Station 1

Station 2

Station 3

Station 4

Station 5

Station 6

Station 7

Station 8

Station 9

Station 1

Station 2

Station 3

Station 4

Station 5

Station 6

Station 7

Station 8

Station 9

Station 1

Station 2

Station 3

Station 4

Station 5

Station 6

Station 7

Station 8

Station 9

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6 Su

bcarrie

r

OFDMA (Multiple Access)

OFDMA

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RUResource Units

time

Station 1

Station 2

Station 3

Station 4

Station 5

Station 6

Station 7

Station 8

Station 9

2 MHz

2 MHz

2 MHz

2 MHz

2 MHz

2 MHz

2 MHz

2 MHz

2 MHz

256 Sub

carrier

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26

26

26

26

26

26

26

26

52

52

26

10

61

06

26

52

52

24

220 MH

z

OFDM vs OFDMA

OFDMA

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time

Station 1

Station 2

Station 3

Station 4

Station 5

Station 6

Station 7

Station 8

Station 9Stat

ion

1

Stat

ion

2

Stat

ion

3

Stat

ion

4

Stat

ion

5

Stat

ion

6

Stat

ion

7

Stat

ion

8

Stat

ion

9

OFDM vs ODFMA

OFDMA

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OFDMP

ream

ble

DL Data Station 1

SIFS

Pre

amb

le

UL ACK Station 1

Contention

Pre

amb

le

DL Data Station 2

Pre

amb

le

UL ACK Station 2

SIFS Contention

Pre

amb

le

DL Data Station 3

Pre

amb

le

UL ACK Station 3

SIFS

OFDMA

Pre

amb

le

SIFS SIFS

DL Data Station 1

DL Data Station 2

DL Data Station 3 Pre

amb

le

MU-ACKRequest

Pre

amb

le UL ACK Station 1

UL ACK Station 2

UL ACK Station 3

OFDM vs ODFMA; Network Efficiency

OFDMA

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Source: HP/aruba

WLAN AX / WiFi 6 advantages

Faster, optimized capacity, IoT ready

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✓Network efficiencyLow latency

ODFMA MU-MIMO BSS Coloring

MIMO

MU-MIMO

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Downstream: wave 1Upstream: wave 2

34

12

MIMO(Single-MIMO)

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MU – MIMO(Multiuser MIMO)

Spatial-Streams

▪ Reduce latency and jitter

▪ Operate more efficiently

▪ Best for low bandwidth applications

▪ Best with small packets

ODFMA and MU-MIMO are complementary

MU-MIMO

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ODFMA

MU-MIMO

▪ Increase capacity

▪ Higher data rates per user

▪ Best for high bandwidth applications

▪ Best with large packets

WLAN AX / WiFi 6 advantages

Faster, optimized capacity, IoT ready

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✓Network efficiencyLow latency

Network efficiencyLow latency✓

ODFMA MU-MIMO BSS Coloring

WLAN AX / WiFi 6 advatages

Faster, optimized capacity, IoT ready

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BSS Coloring

Overlapping WLAN Cells

BSS Coloring

BSS Coloring and Spatial reuse

BSS Coloring

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Relaible Communication radius

Interferenceradius

AP1 AP2

Channel 36 Channel 36

Relaible Communication radius

Interferenceradius

STA-A

STA-B

WLAN B WLAN A

BSS Coloring and Spatial reuse

BSS Coloring

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AP1 AP2

Channel 36 Channel 36

STA-A

STA-B

< -62 dBm?

Signal detect

> -82 dBm

(CCA Threshold)

Read colour

demodulate trafic

same colour

CSMA/CA

no

no

yes

yes

yes

no

> -62 dBm

yes

transmitting

no

(CCA Threshold)

Non- Coloring vs BSS Coloring

BSS Coloring

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BSS A

BSS B

BSS A

BSS B

Without coloring

With coloring

One packet at a time

Simultaneously with transmission in other BSS‘s

▪ Increase capacity

▪ Adaptive Clear Channel Assessment (ACCA) can adjust signal level threshold

▪ Decrease channel contention problem

▪ Signals with same BSS color use a low RSSI threshold for deferral, therefor reducing collision in same BSS.

▪ Signals with OBSS use a higher RSSI threshold for deferral, therefor allowing more simultaneous connection

▪ It provides some degree of airtime fairness

“BSS colouring” or “Spatial Reuse” Benefits

BSS Coloring

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WLAN AX / WiFi 6 advantages

Faster, optimized capacity, IoT ready

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✓Enhanced WLAN coexistenceMore network capacity✓

Network efficiencyLow latency

Network efficiencyLow latency✓

ODFMA MU-MIMO BSS Coloring

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https://content.aerohive.com/802.11ax_dummies_book

Aruba white paper: https://www.arubanetworks.com/assets/wp/WP_802.11AX.pdf

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