beyond 802.11n · 4 gigabit wi-fi (ieee 802.11ac) goal a maximum multi-sta throughput of at least...
TRANSCRIPT
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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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Wi-Fi network: state of the art
KRnet 2013
Wi-Fi network: state of the art
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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
Gigabit Wi-Fi (IEEE 802.11ac)
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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
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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
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Gigabit Wi-Fi (IEEE 802.11ac)
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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Gigabit Wi-Fi (IEEE 802.11ad)
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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Gigabit Wi-Fi (IEEE 802.11ad)
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
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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
Extended Wi-Fi (IEEE 802.11af)
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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
Extended Wi-Fi (IEEE 802.11af)
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)
Extended Wi-Fi (IEEE 802.11af)
KRnet 2013
Extended Wi-Fi (IEEE 802.11af)
The PHY for one TVWS channel (6MHz, 7MHz or 8MHz) is based on the 40MHz VHT PHY (128FFT).
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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
Extended Wi-Fi (IEEE 802.11ah)
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
Extended Wi-Fi (IEEE 802.11ah)
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
8 2.9 Mbps to 39 Mbps 5.8 Mbps to 78 Mbps
16 5.8 Mbps to 78 Mbps 11.7 Mbps to 156 Mbps
KRnet 2013
Extended Wi-Fi (IEEE 802.11ah)
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
Extended Wi-Fi (IEEE 802.11ah)
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
Extended Wi-Fi (IEEE 802.11ah)
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
Extended Wi-Fi (IEEE 802.11ah)
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
Extended Wi-Fi (IEEE 802.11ah)
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 and Application
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 and Application
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 and Application
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 Technology and Application
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
29 KRnet 2013