Vehicle to Vehicle Communications and the need for more Wi...
Transcript of 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
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• 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
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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
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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)
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JASPAR Automotive Use cases (WFA)
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• 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
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• 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
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• 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
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• Theoretical analysis must be followed up with bench and field tests
Proper coexistence testing is crucial
In-Car Test Lab
Field testing
Bench testing
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• 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
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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
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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
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• 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)
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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
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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
Exp. U-NII-4[40 MHz]
Center Chan 167
Exp. U-NII-4[20 MHz]
Center Chan 177
Exp. U-NII-4[20 MHz]
Cente Chan 173
Exp. U-NII-4[20 MHz]
Center Chan169
Exp. U-NII-4[20 MHz]
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[40 MHz Channels]
ProposedU-NII-4 Expansion
[160 MHz Channels]
Exp. U-NII-4[80 MHz]
Center Chan 171
ProposedU-NII-4 Expansion[80 MHz Channels]
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?
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• 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
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Thank you!