vehicle to vehicle communications and the need for more wi...

Vehicle to Vehicle Communications and the need for more Wi-Fi spectrum: Can unlicensed devices safely use critical V2V licensed spectrum?

Jim Lansford, Ph.D. Fellow, Global Standards Chair, Wi-Fi Alliance Automotive Market Segment Task Group Chair, IEEE 802.11 DSRC Coexistence Tiger Team

IEEE ComSoc SCV 11-June-2014

2 © Cambridge Silicon Radio Limited 2014 ComSoc SCV – June 2014 · Lansford

• Former faculty, University of Colorado at Colorado Springs • Former research faculty, Georgia Tech (GT Research Institute) • Former CTO, Momentum Microsystems (wireless PAN) • Former Wireless Systems Architect, Intel

− Chair of HomeRF Technical Committee

• Former VP, Business Development and CTO at Mobilian (Wi-Fi/BT combo) − Chair, IEEE 802.19 Coexistence Technical Advisory Group − Vice chair, 802.15.2 (802.11-Bluetooth coexistence) − Contributor to 802.11g and Bluetooth 1.2

• Former CTO at Alereon (UWB chips) − Co-chair, 802.15.3a (High speed WPAN)

• Currently Standards Architect at CSR − My role: 802.11 and Wi-Fi Standards, strategy, and related regulatory issues − Wi-Fi Alliance: Vice-chair, Long Range Strategy TG and Vice-chair, Wi-Fi SensorNet MTG − 802.11: Vice-chair, 802.11 Wireless Next Generation and Chair, DSRC Coexistence Tiger Team

• Currently adjunct faculty at CU-Boulder (ITP)

My background


The automobile is the “Fourth Screen”

WLAN began as a way to connect computers to infrastructure networks Laptops dramatically accelerated the trend – almost all laptops now have WLAN The next wave of connectivity was smartphones WLAN is now becoming common in TVs, Blu-Ray players, game decks and other CE equipment The connected car is the next screen Beyond the 4th screen? No screen at all! (IoT/IoE/M2M)

From laptop to smartphone to TV to automobiles – the 4th screen


Use Cases for WLAN in IVI

Internet connectivity (via in-car modem or tethering) Streaming or Fast content downloading at hotspots (Redbox “filling

station”) Displays (mirroring, A/V content to other screens)


JASPAR Automotive Use cases (WFA)


• Wi-Fi (2.4/5GHz) • Bluetooth (2.4GHz) • GPS (1.575GHz) • DSRC (5.9GHz) • Cellular (LTE, etc)

− (800/900/1800/1900/2100/2500MHz) • NFC (various) • Satellite radio

− (2320-2345MHz/US, DAB 1452-1492MHz) • AM/FM broadcast (540-1610kHz, 87.9-107.9MHz)

• Wireless charging

Wi-Fi is one of many wireless technologies in the Connected Car

DSRC will be used for collision avoidance


• Miracast uses H.264 video codec − For standard resolution video: ~5Mbps average, 25Mbps peak − For med-high res (720p) video: ~20Mbps average, 100Mbps

peak − For high res (1080p) video: ~40Mbps average, 200Mbps peak

• 5GHz needed to support Miracast use cases − 40MHz 802.11n can support up to 135Mbps PHY rate (single

spatial stream, MCS7, short GI) − Miracast uses RTP and UDP for streaming, which can achieve

approximately 67% MAC efficiency – so about 90Mbps will be available at the top of the stack

− 40MHz 802.11n very difficult to use in 2.4GHz because of congestion

− >=80MHz bandwidth required for higher resolution video and reliability

− 5GHz bands necessary for Wi-Fi display and video streaming

Bandwidth requirements for Wi-Fi Display/Miracast


• Consumers will bring smartphones and other devices into the car

• Wi-Fi and Bluetooth share the 2.4GHz band • Wi-Fi and DSRC are in adjacent 5GHz bands

− Regulatory proposals to allow band sharing • Cellular bands are near GPS, Bluetooth, Wi-Fi

− 800/900/1800/1900/2100/2500MHz

Wireless in Automobiles: A systems approach is needed

“Shark fin” w/DSRC antenna

In-dash head unit


• Theoretical analysis must be followed up with bench and field tests

Proper coexistence testing is crucial

In-Car Test Lab

Field testing

Bench testing


• Band definitions: − U-NII-1 − U-NII-2 − U-NII-2e − U-NII-3 − U-NII-4 (proposed – shared with ITS band)

• There is no single globally harmonized 5GHz band for 802.11n/ac − U-NII-1 is the closest – Allowed in US (indoor+outdoor), Japan

(indoor) and EU (indoor)…no DFS − FCC recently allowed U-NII-1 outdoors at up to 1 Watt EIRP − Efforts underway to push EU and Japan to follow FCC with U-

NII-1 use outdoors

Global spectrum availability at 5GHz


5GHz global spectrum at a glance

US

Europe

Japan

14

0

13

6

13

2

12

8

12

4

12

0

11

6

11

2

10

8

10

4

10

0

16

5

16

1

15

7

15

3

14

9

64

60

56

52

48

44

40

36IEEE channel #

20 MHz

40 MHz

80 MHz

5170

MHz

5330

MHz

5490

MHz

5710

MHz

5735

MHz

5835

MHz

160 MHz

14

0

13

6

13

2

12

8

12

4

12

0

11

6

11

2

10

8

10

4

10

0

64

60

56

52

48

44

40

36IEEE channel #

20 MHz

40 MHz

80 MHz

5170

MHz

5330

MHz

5490

MHz

5710

MHz

160 MHz

China

DFS

5855 MHz

5925 MHz

ITS

16

9


FCC changes in March 2014 • U-NII-1 band (5150 to 5250 MHz)

− Indoor restriction dropped − TX Power limits

• Indoor: 1W conducted; 4W EIRP • Outdoor 250mW conducted; 1W EIRP with antenna restriction

• U-NII-2 bands (5250 – 5350 and 5470 – 5725 MHz) − DFS detection increased to 100% of the bandwidth* − Updated the BIN 1 waveform

• U-NII-3 band (5725 to 5825 MHz) − Extended by 25 MHz (to 5850 MHz) − Change from 15.407 limits to 15.247 limits (1 Watt)

• All U-NII bands − Require manufacturers to improve software security to prevent user

modification of regulatory required parameters − No requirement to disable devices when modifications are made

US FCC Changes to U-NII-1


• FCC allocated 75MHz of spectrum in the 5.9GHz band (5850-5925MHz) for Dedicated Short Range Communications (DSRC) in October 1999

In FCC NPRM 13-22 (13-49), the FCC requested comments on a potential sharing of the DSRC band, to understand if a feasible sharing solution that protects DSRC users could be developed. DSRC would remain as a primary user of the band The new band would be designated U-NII-4

• 802.11ac could be modified to operate in this new UNII-4 band if approved by the FCC

• FCC did not specify the framework or etiquette by which band sharing would occur

802.11p/DSRC and U-NII-3/4 band sharing updates (1/3)


802.11p/DSRC and U-NII-3/4 band sharing updates (2/3) – A proposal

• Add new 10MHz CCA to 802.11ac − Use Carrier Sense of 802.11p preamble, NOT energy detect

• No Changes to DSRC − Similar to 802.11a protection, but 10MHz CCA

• Some changes to 802.11ac − New CCA for 10MHz BW – not in existing spec − DSRC Channels 172 and 178 sensed with CCA – other channels

TBD − CCA for 10MHz BW exactly the same as 802.11a detection at ½

clock rate − IEEE document 13/994r0 suggests a “NAV” during and for 10

seconds after the last PHY-CCA.indication(BUSY,(DSRC10_CCA)) − Other details: CCA level, SIFS, slot times, etc. need to be worked

out

802.11p PPDU


802.11p/DSRC and U-NII-3/4 band sharing updates (3/3)

5850

DSRC[10 MHz]Service

Chan 184

DSRC[10 MHz]Service

Chan 182

DSRC[10 MHz]Service

Chan 180

DSRC[10 MHz]Control

Chan 178

DSRC[10 MHz]Service

Chan 176

DSRC[10 MHz] Service

Chan 172

DSRC[10 MHz] Service

Chan 174Res.

5840

5855

5860

5865

5870

5875

5880

5885

5890

5895

5900

5905

5910

5915

5920

5925

5845

Exp. UNII[160 MHz]

Center Chan 163

Exp. U-NII-4[40 MHz]

Center Chan 175


Center Chan 167


Center Chan 177


Cente Chan 173


Center Chan169


Center Chan 181

5850

5840

5855

5860

5865

5870

5875

5880

5885

5890

5895

5900

5905

5910

5915

5920

5925

5845

Frequency(MHz)

Frequency(MHz)

DSRC Band[10 MHz Channels]

ProposedU-NII-4 Expansion[20 MHz Channels]


ProposedU-NII-4 Expansion

[160 MHz Channels]


Center Chan 171


DSRC

U-NII-4

U-NII-4

U-NII-4

U-NII-4

Fro

m 1

3/5

41r1

DSRC_CCA10: Defers to all BSM traffic in Channel 172

DSRC_CCA10: Defers to all CCH traffic in Channel 178

Possible CCA Protection?


• The automobile isn’t a giant smartphone − Nor is it a small living room − Proper analysis, design, and measurements are needed to

assure multiple wireless technologies operate properly in the confines of a vehicle

• Billions of new IoT devices will cause further spectrum congestion

• Video use cases will accelerate the need for additional spectrum for Wi-Fi − Wireless video streaming in cars will become commonplace − Most of this will be in the 5GHz band

• DSRC is adjacent to 802.11ac in U-NII-3 • Proposed band sharing between Wi-Fi and DSRC in

“U-NII-4” will require careful analysis and testing

Conclusion


Thank you!

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