Beam Alignment and Tracking for Autonomous Vehicular Communication - - PowerPoint PPT Presentation

Beam Alignment and Tracking for Autonomous Vehicular Communication using IEEE 802.11ad-based radar

Next GEneration NEtworks and SYStems Lab

Presenter: Kaushik R. Chowdhury Authors: Guillem Reus, Kumar Vijay, Carlos Bocanegra, Yonina Eldar and Kaushik Chowdhury.

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• The need of 802.11ad radar
• 802.11ad beamtraining overview
• Radar within 802.11ad
• System design
• Performance evaluation

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Agenda of the talk

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Modern Communications require high data-rates IEEE 802.11ad enables high throughput at 60GHz IEEE 802.11ad beamtraining not suitable for mobility. IEEE 802.11ad radar-aided beamtraining

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Introduction

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802.11ad - MAC Layer

BTI

The AP sends beacon frames across its sectors to allow users to detect the most beneficial sector

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A-BFT

Users reply back with the best BS

• sector. This information is shared across

every sector so that the BS is able to choose the user’s best sector as well.

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802.11ad - MAC Layer

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The AP communicates the sector selection to the connected devices. ATI

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802.11ad - MAC Layer

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Definition

Two length N unimodular sequences GaN and GbN are Golay complementary if they satisfy the perfect aperiodic autocorrelation property, i.e., Autocorrelation properties applications

• Radar: Zero range sidelobes aid

identifying closely spaced targets.

• Communication: Accurate channel

estimation.

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Radar frames withinthe IEEE 802.11ad

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The four correlators outputs, each for a 256 Golay Sequence, are delayed and summed up Final channel estimate is the mean of two Golay correlators outputs. 2-D FFT in delay-Doppler plane Peak Detection

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Position estimation Velocity estimation

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IEEE 802.11ad Radar Signal Processing

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Assumptions

• Straight road with cars at moving at a constant velocity.
• LOS.
• Overlap between the communication sectors

V2I IEEE 802.11 sync

• 1. During the BTI, the

BS estimates cars location.

• 2. BS allocates detected

cars along the A-BFT.

• 3. Vehicles finalize the

handshake

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System Architecture

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Design constraint: Narrow beamwidths are preferred over short distances.

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Beamwidth – Distance analysis

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• Accurate velocity estimations require low ∆𝜉
• Higher overlap ratio reduces misalignment probability

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Performance evaluation

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We reduce the overhead compared to the IEEE 802.11ad beamtraining procedure.

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Performance evaluation