V2X, V2I and the Cellular Infrastructure

Prof. Sanjay Shakkottai, DirectorAshley H. Priddy Centennial Professor of Engineering

Director, Wireless Networking and Communications Group

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Wireless Networking and Communications Group

125 Grad Students

Affiliateschampionlargefederalproposals,providetechnicalinput/feedback,researchsupport

WNCGprovidespre-competitiveresearch,technicalexpertise,firstaccesstostudents

Significantnumberofstudentsintern/workfull-timeforaffiliates

Affiliatesproviderealworldcontext

Industrial Affiliates22 Faculty

$- $2,000,000.00$4,000,000.00$6,000,000.00

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Do automated vehicles need to be connected?

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Myth: fully autonomous operation is enough

Reality: automation is much better with

connectivity

Slide courtesy: Prof. Robert Heath

Expand the sensing range of the vehicle

Allows interactions between vehicles with

different automation levels

More informed safety decisions

Benefits of connectivity

Higher levels of traffic coordination like platooning

Slide courtesy: Prof. Robert Heath

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Connectivity enhanced with infrastructure sensing

Can be used for other functions, for example

more precise navigation

Supports sensing of the environment, does not require

all cars to have complete sensing equipment

Helps coordinate traffic through intersections,

eliminating lightsEffective with non-connected cars, bicycles, and pedestrians

Slide courtesy: Prof. Robert Heath

< 1ms 1ms 10ms 100ms

1 Mbps

10 Mbps

100 Mbps

1 Gbps

throughput

latency

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DRIVEN BYTHE CLOUD

DRIVEN BYTHE IN-CAR INFO

DATA

positioninfo

limited sensor

processed sensor

raw sensor

mixed levels of automation

Slide courtesy: Prof. Robert Heath

u Current Stateª Cellular: Large cells with tens of users per sector/cellª Cellular: Time-scale separation between scheduling and mobile-to-cell

association

u Moving Forwardª Many small cells with few(er) users per cell; fast(er) transitions between cellsª Heterogeneous capabilitiesª Mixture of cellular and D2D (e.g. V2V) traffic over shared spectrumª Much smaller slot timescales (100s of microsecs instead of milliseconds)ª Much larger bandwidthª Sensing built into the infrastructure?

Cellular Infrastructure: Today’s Setting and Moving Forward

Infrastructure: Looking Ahead

1. Degrees of freedom: Large number and diversity of users/frequencies 2. Densification: Macro base-station + densely deployed access nodes (on

traffic poles?)3. Rapid Association Flux: “Micro” mobility + small cells4. Sensing + Communications: Infrastructure aided location informationBS/AP image courtesy: http://intersales.com.au/GPSNetwork.aspx

Network Architecture #1: Who Controls the Network?

u Association flux – much more rapidu Cellular: Users transition between cells at a faster time-scale

ª Number of users per cell smallerª Time-scale separation between scheduling and association unclear

u D2D traffic embedded with cellular over shared spectrumª Control needs to rapidly switch between D2D (V2V) and cellular

u More efficient to implement these tasks on the device

Network Inversion: Device driven association and channel resource allocation

Network Architecture #2: The MAC Architecture

u Local backlogs or HOL delay used for schedulingu Data center used for planning / long-term parameter settingsu Looking Forward

ªMove from a interference limited regime to a link budget limited regime

ªMoving from a state-driven allocation to a statistics-driven allocation

ªSwitch between sensing and communications, while dealing with hysteresis

Leverage the cellular data center for real-time global resource allocation