wigig and halow - wi-fi at new frequency bands

WiGig and HaLow –Wi-Fi at New Frequency BandsApril 19th, 2017

Veli-Pekka “VP” Ketonen

@VPonwireless

WiGig and HaLow at a glance

WiGig / 802.11ad

• Operates in the 60 GHz frequency band• Wireless docking and HD video

connections • Seamless handoffs between bands• Up to 6.75 Gbit/s data rates• Adjusted 802.11n MAC with more

spectrum bandwidth, no-MIMO• Standard ready, first products in the

market

Halow / 802.11ah

• In US, operates in the 915 MHz ISM band• IEEE wide area IoT standard• 150kbit/s - 234 Mbit/s data rates• 802.11ac PHY with carrier bandwidths cut

down by 10x, up to 4 SS• Adding new innovative MAC features of

which many are included to 802.11ax• IEEE Standards Board approved in Dec

2016, no commercial products available

3

Spectrum bandwidth with different Wi-Fi standards

4

WiGig and HaLow market positioning

Björn Ekelund,Ericssonhttps://www.slideshare.net/bjornopekelund/technologies-for-the-internet-of-things?qid=362d13c5-ccb1-4a7c-bd99-0fe7a3908d4e&v=&b=&from_search=9

IoT

WiGig/802.11ad, deeper dive

Graphics,ABIResearch,2016https://www.qualcomm.com/documents/abi-research-80211ad-will-vastly-enhance-wi-fi

WiGig Use Cases

7

Use cases

7

ABIResearch,April2016https://www.qualcomm.com/documents/abi-research-80211ad-will-vastly-enhance-wi-fi

WiGig PHY (Layer 1)

802.11ad PHY overview• Directional Multi-Gigabit (DMG) PHY• Three modes

• Control PHY• Low SNR operation prior to beamforming• 27.5 Mbit/s, DSSS π⁄2-BPSK• 10 dB better sensitivity than SC PHY

• Single Carrier (SC) PHY• Low power, low complexity• Up to 16 QAM, 4.62 GBit/s (MCS 12)

• OFDM PHY (optional)• High performance• Up to 64 QAM, 6.75 Gbit/s (MCS 24)

• No MIMO• Bi-directional beamforming• Preamble training with Golay sequences

9Eldad Perahia,MichelleX.Gonghttps://pdfs.semanticscholar.org/b2d7/a3feddbeffa2ce1001c2e673f79e581094bf.pdf

RajJain,WashingtonUniversityinSt.Louishttp://www.cse.wustl.edu/~jain/cse574-14/ftp/j_07sgh.pdf

10

Data rates/MCSsSingleCarrierandControlrates

OFDMrates

https://en.wikipedia.org/wiki/Wireless_Gigabit_Alliance#cite_note-28

Low-powersingle-carrierdataratesnotshown

ControltrafficusesMCS0

BPSK

QPSK

16QAM

11

Channelization

11JohnHarmon,Keysighthttp://www.keysight.com/upload/cmc_upload/All/22May2014Webcast.pdf?&cc=US&lc=eng

12

Beamforming with with antenna array

Silversima Inc.,productbriefhttps://siversima.com/wp-content/uploads/PB_TRX-BF01_v1.pdf

Eldad Perahia,MichelleX.Gonghttps://pdfs.semanticscholar.org/b2d7/a3feddbeffa2ce1001c2e673f79e581094bf.pdf

13

Range and maximum throughput

13

Thomas Nitsche et. al., IMDEA Networks Institute/Universidad Carlos III http://networks.rice.edu/files/2014/10/11adPaper.pdf

RFlink:1mfreepathlossis21dBhigher(68dBvs47dB)Noisefloorsis17dBhigherdueto2GHzBWAppr.12dBantennagainavailableatbothends

WiGig MAC (layer 2)

15

802.11ad MAC overview

• Directional antenna patterns used at both ends• Ad hoc like selection of controlling device• Transmissions are centrally scheduled• Beam training and tracking is essential• Beacons need to be swept to all directions• Multiple simultaneous transmission at the

same frequency are possible• Relays can be used if LoS is blocked

15


16

Personal Basic Service Set (PBSS) and PBSS Central Point(PCP)

• Personal Basic Service Set (PBSS) • Group of stations that communicate

• PBSS Central Point (PCP)• Provides airtime coordination/scheduling and timings using beacons• Ad hoc method used for determining PCP• Only PCPs transmit beacons• Overlapping PBSS avoid interference by electing a Synchronization PCP (S-

PCP) for the PCP cluster• PCP handover supported


17

Beacon Interval super-frame

Each Beacon Interval is divided in to four main parts1. Beacon Time (BT)

• New station discovery. Only PCP can send beacons during beacon time2. Associating Beamforming Training (A- BFT)

• PCP performs antenna training with its members3. Announcement Time (AT)

• PCP polls members and receives non-data responses (association,…)4. Data Transfer Time (DTT)

• All stations exchange data frames in a dedicated service period (SP) or • by contention in contention-based period (CBP)

Beaconformat Beaconantennasweep


18

Hybric MAC, scheduled and contention based• Two different channel access methods• Dynamic channel time allocation

• During Service Periods, SPs• Scheduled centrally controlled transmissions (PCF mode extension)• All stations exchange data frames in a dedicated service period (SP)• More flexible. Stations get channel time, not just one frame

• Contention based medium access• During Contention-Based Periods, CBPs• Hybrid TDMA-CSMA based on EDCA

• Physical Carrier Sense / Virtual Carrier Sense• NAV, QoS, frame aggregation, block ACKs

• Directional Band CTS (DBandCTS), DBand Denial to Send (DBandDTS), DBandCF-End• NAV for each source-destination pair

• Pseudo-static TDMA channel time allocation• Service period may be allocated semi-permanently to a pair of nodes


19

Beamforming

19

RobertW.HeathJr.,TheUniversityofTexas,Austinhttps://web.stanford.edu/~apaulraj/workshop70/pdf/mmWaveMIMO_Heath.pdf

20

FST and Relay operation

• Fast Session Transfer (FST) • Seamless integration of 60 GHz with other bands for multiband devices• FST allows transition from any band/channel to any other band/channel• Simultaneous and non-simultaneous operation supported• Transparent operation keeps MAC address unchanged, non-transparent alters

the address• Relay operation• Switch relay

• From source to destination• Co-operation relay (hub, repeater)

• Amplify and Forward (AF)• Decode and Forward (DF)• Direct and relayed signal may both be used for spatial diversity

20


21

802.11ay (WiGig2) improves 802.11ad/WiGig further

• Objective• > 20 Gbit/s throughput

• Technologies• Channel bonding• MIMO• Backwards compatibility with -ad

• To be completed in 2019

21DorothyStanley,HewlettPackardEnterprisehttps://www.ietf.org/edu/documents/95-802-11-Tutorial.pdf

ABIResearch,April2016https://www.qualcomm.com/documents/abi-research-80211ad-will-vastly-enhance-wi-fi

22

Multiplexing techniques in 802.11ad

22

Channel

OFDMwith1spatialstream

Highattenuationat60GHz

Bi-directionalhighgainbeamsteering

Scheduledserviceperiodsand

contentionbasedperiods

Fastsessiontransferwithsimultaneousoperation

Relaywithcombining

WiGig Products

24

Access points with WiGig support, examples

24

TP-LinkAD7200WirelessWi-FiTri-BandGigabitRouter(TalonAD7200)

NETGEARNighthawkX10–AD7200802.11ac/adQuad-StreamMU-MIMOWiFi Router Acelink BR-6774AD

MarketedAPclassspecification:Upto4620Mbit/sforasinglechannelinthe60GHz802.11adUpto1733Mbit/sforfour802.11acWave25GHz,Upto800Mbit/sforfour-channel802.11n2.4GHzNote:TheseareSingleCarrier(SC)devices

25

Terminals with WiGig support, examples

http://www.networkworld.com/article/3117803/computers/acer-travelmate-802-11ad-notebook-an-industry-first-you-might-never-need-or-use.html

60 GHz WiGig (802.11ad) wireless docking connectivity for mobile client device (2 in 1, tablet, laptop) with up to 4.7 Gbps of bidirectional throughput.

http://www.intel.com/content/www/us/en/wireless-products/tri-band-wireless-ac-wigig-18260-product-brief.html

http://www.androidauthority.com/le-max-pro-will-be-the-first-phone-with-snapdragon-820-ultrasonic-sensor-and-wifi-802-11ad-665995/

LeTV LeMaxProQualcommSnapdragon820ThefirstphonewithWiGigNoavailabilityinUS

SomephoneswiththelatestQualcommSnapdragon835expectedtohaveWiGigsupport

26

Wi-Fi Alliance certified WiGig products (4/13/2017)

Wi-FiAlliance802.11adcertifiedproductshttp://www.wi-fi.org/product-finder-results?sort_by=certified&sort_order=desc&certifications=62

DellLatitude7480

27

Measured performance (Tim Higgins, SmallNetbuilder)

• TP LINK Talon AD7200 Multiband router (2.4, 5, 60 GHz)• Acer TravelMate TMP446-M-77QP notebook (802.11ad support)• Measured maximum about 1500 Mbit/s with dual 2 Gbit/s Eth capacity

TimHiggins,SmallNetBuilderhttps://www.smallnetbuilder.com/wireless/wireless-reviews/33009-tp-link-talon-ad7200-multi-band-wi-fi-router-reviewed?start=3

28

Market forecasts for WiGig

28

ABIResearch,2016https://www.qualcomm.com/documents/abi-research-80211ad-will-vastly-enhance-wi-fi

Wi-Fichipsetshipmentsbynumberofbands Totalsinglebandandmultiband802.11adWi-Fichipsetshipmentsbyproductcategory

HaLow/802.11ah, deeper dive

30

Wi-Fi needs improvements to be IoT ready

Total number of IoT devices is expected to be 50 billion by 2020*

while in “traditional” Wi-Fi• MAC overhead is significant especially with small packets• Consumes too much energy for long term battery operation

• Cannot handle many thousands of stations/AP• Coverage is not sufficient for IoT use

* D. Evans, The Internet of Things – how the next evolution of the Internet is changing everything, Cisco Internet Business Solutions Group (IBSG), 2010Number has been later lowered to 20 - 30 billion devices by 2020

HaLow Use Cases

32

Use Case 1 : Sensors and meters

RolfdeVegt,QualcommAtheroshttp://www.comsocscv.org/docs/IEEE%20ComSoc_11ah_Opportunity_V6_0715.pdf

33

Use Case 2 : Extended range Wi-Fi


34

Examples of potential 802.11ah devices, per segment


HaLow PHY (layer 1)

36

802.11ah PHY overview• S1G PHY based on 802.11ac with 1/10 clock rate

• Spectrum bandwidths are divided by 10 • 160 MHz -> 16 MHz• 20 MHz -> 2 MHz

• 1 MHz channel width is a special case. It has 32 subcarriers• OFDM symbol 10x longer

• Mandatory PHY features • 1, 2 MHz channel widths• Single spatial stream• Repetition for 1 MHz MCS10

• Optional PHY features • 1, 2, 4, 8 & 16 MHz channel widths• Four spatial streams• STBC & LDPC coding• Beam sounding• Short Guard Interval• Traveling pilots

37

Data rates and bandwidths

16MHz

8MHz

4MHz

2MHz

1MHz

20MHz

Minimum11n/acbandwidth

11ahBandwidthModes

HigherDataRates

ExtendedRange

150Kbps– 4Mbps

650Kbps– 7.8Mbps

1.35Mbps– 18Mbps

2.9Mbps– 39Mbps

5.8Mbps– 78Mbps

Mandatory&GloballyInteroperablemodesoptimizedforsensornetworking

OptionalhigherdataratemodesforextendedrangeWi-Fi

6.5Mbps– 78Mbps

Note:SinglespatialstreamandLongGuardintervaldataratesdisplayed

> 1000m

4SS,4usSGI=>234Mbit/s

RolfdeVegt,QualcommAtherosIEEE-SAIoT workshop802.11ahOverview

38RolfdeVegt,QualcommAtheroshttp://www.comsocscv.org/docs/IEEE%20ComSoc_11ah_Opportunity_V6_0715.pdf

Spectrum allocations and RF power

39

Traveling pilots and pilot boosting

• In outdoor case, a reflection from moving vehicle may cause Doppler shift. This degrades receiver capability to decode signal properly• Current 802.11 system only allow channel

estimation in the beginning of the frame during the Long Training Field (LTF)• Traveling pilots allow continuous refresh of

channel estimation take during the frame transmission• Pilot signal level boosting further improves

channel estimation

Mathworks,Inc.https://www.mathworks.com/help/wlan/examples/802-11ah-waveform-generation.html?requestedDomain=fr.mathworks.com

40

802.11ac vs. 802.11ah PHY

Keysight Inc.http://www.keysight.com/upload/cmc_upload/All/IoT_Seminar_Session1_Explosion_of_the_Internet_of_Things.pdf?&cc=US&lc=eng

HaLow MAC (layer 2)

42

802.11ah MAC overview

• 802.11ah MAC adds many innovative improvements• Operating on a different band

removes the need for the MAC to be completely backward compatible

42VictorBaños-Gonzalezet.al.IEEE802.11ah:ATechnologytoFacetheIoTChallengehttp://www.mdpi.com/1424-8220/16/11/1960

43

Restricted Access Window (RAW)• Simple scheduling scheme• In beacons, AP assigns a group of

devices to certain time slots• Devices can access the channel only

during the assigned timeslot• Devices contend for medium access

within the slot with EDCA• RAW decreases probability of

collisions with thousands of devices• RAW also enhances power efficiency

since stations can sleep during alien slots

Orod Raeesi et.Al.,TampereUniversityofTechnologyhttps://www.researchgate.net/publication/269273626_Performance_Enhancement_and_Evaluation_of_IEEE_80211ah_Multi-Access_Point_Network_Using_Restricted_Access_Window_Mechanism

Throughputfor9APscase Energyefficiency

44

Response Indication Deferral (RID) and Bi-Directional TXOP (BDT)Response Indication Deferral (RID)• New simpler virtual carrier sense

• NAV not supported due to frame efficiency improvement

• RID is countdown like NAV. RID can be updated to shorter value during count down, unlike NAV• RID estimates durations to achieve better efficiency

Bi-directional TXOP (BDT), speed frame exchange• Station and AP can exchange frames within one TXOP• Implicit reception without ACK• Faster exchange, reduces overhead, eliminates contention, saves energy

45

BSS coloring

• A technique to improve co-existence of overlapping BSSs (OBSS) and allow spatial reuse within one channel• Each BSS (SSID) is assigned a specific

“color” identifier• Frames from neighbor SSIDs can be

treated differently when assessing channel availability (Clear Channel Assessment, CCA)• Increases channel availability

DorothyStanley,HewlettPackardEnterprisehttps://www.ietf.org/edu/documents/95-802-11-Tutorial.pdf

46

Group sectorization• A method for space – time multiplexing

within one channel• Stations at the opposite ends of the AP

coverage area cannot hear each other and number of stations can be very high• Location aware grouping allows

simultaneous operation for stations inside one sector interval• Group sectorization and RAW further

complement each other• Antenna beam forming or similar capability

is needed. It’s implementation is not standardized• Benefits include improved quality, capacity

and power efficiencyMuhammadQutab-Ud-Din,TampereUniversityofTechnologyhttp://dspace.cc.tut.fi/dpub/bitstream/handle/123456789/23538/Qutabuddin.pdf?sequence=1

47

Sub-channel Selective Transmission (SST)

• 802.11ah standard allows operation with up to 16 MHz channels• Standard mandatory supported channels are 1 MHz and 2 MHz• Sensors will prefer to use narrow channels for reduced energy

consumption• Narrower channels are more likely to experience and suffer from deep

fading • SST allows stations to rapidly select and switch to different channel

widths and channels between transmissions to counter fading over narrow sub-channels

Evgeny Khorov et.al.IITPRAShttp://infonet.cse.kyutech.ac.jp/lecture/graduate/doc/sensor.pdf

48

Relay• Relay AP and Relay station needed• APs and stations can operate as relays

• 802.11s Mesh is too complex for IoTpurpose

• Max two hops

• Relay discovery by station• Two hop TXOP sharing when using

the same channel• Flow control to avoid buffering• Benefits

• Extend range• Improve reliability• Reduce energy consumption


49

Mac efficiency and energy saving improvements• Association Identifier (AID) maximum increased from 2007 to 8192 stations

• Grouping of stations with similar characteristics, 4 level AID structure

• Fast association and authentication supporting thousands of stations

• Short frames to reduce active TX/RX time• Short MAC header• Short beacon frame (and compressed TIM) to reduce beacon decode times• Short probe request/response• Short control frames

• Increased standby time: Expand listen and MAX BSS idle periods to allow STAs sleep for hours/day. Idle times increased from 18.64h up to a year

• Target Wake Up Time (TWT) allows station sleep also over beacons over longer times

• Enable AP and relay nodes to sleep

• Client timing relaxation, useful for battery operated devices• Maximum awake interval, Recovery time


50

Multiplexing techniques in 802.11ah

50

ChannelwithSST

OFDMwith4spatialstreams

RestrictedAccessWindow

withEDCA

4levelhierarchicaldevicegroups

Groupsectorization

BSScolor

Relay

51

802.11ah performance, outdoor

51

7xcoverageimprovementvs.VHT20–ac

Outdoorupto1500m,indoor1000m

VictorBaños-Gonzalezet.al.,Universitat Politècnica deCatalunya BarcelonaTechhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC5134619/pdf/sensors-16-01960.pdf

HaLow Products

53

Products

• No products yet available• Cadence silicon design vendor offers 802.11ah functionality for integration to their

customer chips• 900 MHz 802.11ah functionality is expected to be added to Wi-Fi access points and

routers• -ax borrowed from -ah

• Scheduling• BSS Coloring• Traveling pilot• Target Wake up time (TWT)• Only narrow band (20 MHz) channels mandatory for 5 GHz

53

54

SummaryHaLow (802.11ah) WiGig(802.11ad)

Standard ApprovedinDec2016 ApprovedinDec2012802.11ayexpectedin2019

Purpose Wi-FiIoT standard Veryhighthroughput

Usecases 1. Sensor networking2. Wearables3. Industrialautomation4. Utilitynetworking5. ExtendedrangeWi-Fi

1. Wirelessdisplay/audio2. HDTVdistribution3. Wirelessdockingstation4. Highcapacitybackhaul5. Cordlesscomputing

PHY 902-928MHz(US)1MHz– 16MHz,1-26 channels(US)150kbit/s - 234 Mbit/s(4SS)Upto4spatialstreams

57240MHz– 63720MHz(US)2160MHz,4channels(US)27.5Mbit/s– 6.75Mbit/s1spatialstream

MAC 802.11+severalimprovementsforhighamountofterminalsandlowerpowerconsumptionManyimprovementsarereusedin-ax

802.11 +severalimprovementtooperatewitharaylikebeamsteeringlinksandassociated“deafness”Seamlesstransitionsbetweenbands

Deploymentmodel AddHaLow radios toupcomingAPsIoT sensorssupportonly–ahstandard

AddWiGigradiostoupcomingAPsandterminals

Products Notyetavailable OnelaptopandafewAPmodelsSeveral PCIe radiocards

Thank [email protected]

Twitter: @VPonwireless

wigig and halow - wi-fi at new frequency bands

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