Fast Millimeter Wave Beam Alignment Omid Abari Haitham Hassanieh, - - PowerPoint PPT Presentation

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Fast Millimeter Wave Beam Alignment Omid Abari Haitham Hassanieh, - - PowerPoint PPT Presentation

Nov 10, 2022 241 likes •527 views

Fast Millimeter Wave Beam Alignment Omid Abari Haitham Hassanieh, Michael Rodriguez , Mohammed Abdelghany, Dina Katabi, and Piotr Indyk Emerging Applications VR stream 7 Gbps of data from PC to headset One autonomous car will generate 4TB of

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SLIDE 1

Omid Abari

Haitham Hassanieh, Michael Rodriguez , Mohammed Abdelghany, Dina Katabi, and Piotr Indyk

Fast Millimeter Wave Beam Alignment

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Emerging Applications

VR stream 7 Gbps of data from PC to headset One autonomous car will generate 4TB of data per day 5G promises 1000 times faster than 4G Today’s wireless networks can not support future applications

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SLIDE 3

mmWave Technology

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SLIDE 4

mmWave Technology

Millimeter Wave Bands Currently we

  • perate here

10GHz 20GHz 30GHz 40GHz 50GHz 60GHz 70GHz 80GHZ 90GHz 100GHz

Frequency Spectrum

Enable high-throughput wireless links

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SLIDE 5

mmWave changes how wireless systems operate

Today: Broadcast

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SLIDE 6

mmWave changes how wireless systems operate

mmWave: Pencil-beam Antennas

Problem Statement: how can we align the beams to establish a link?

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mmWave radios use phased arrays to create a beam

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SLIDE 8

𝑂 : number of possible directions

Client AP 𝑂 directions

Naïve Approach: Exhaustive Scan

O 𝑂- measurements à Too slow

𝑂 directions

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SLIDE 9

802.11ad Scan

AP Client

Stage 1: Client uses omni-directional; AP scans directions

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SLIDE 10

802.11ad Scan

Stage 2: AP uses omni-directional; client scans directions

AP Client

O 𝑂 measurements àStill Too Slow

[MOBICOM’14, SIGMETRICS’15, NSDI’16]

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SLIDE 11

Can we find the best beam alignment without scanning the space?

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Agile-Link

  • A millimeter wave system that can quickly

establish a link without scanning the space

  • Works within the existing 802.11ad

standard, and can support both clients and access points

  • Implemented and evaluated in practical

settings

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SLIDE 13

30 60 90 120 150 180

AP

Client

60o

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Construct a Multi-Armed Beam: Simultaneously collects signals from multiple directions.

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Agile-Link Idea

Potential Direction of the Client: 0o, 60o, 90o or 120o 40o, 60o, 100o or 150o 60o is direction of client

30 60 90 120 150 180

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  • 1. How do we create multi-armed beams?
  • 2. What is the best choice of multi-armed

beams to minimize the number of measurements?

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Creating Multi-Armed Beams

ℎ/ ℎ- ℎ0 𝑏/ 𝑏0 Phase Shifters 𝑧𝑗

For an Antenna Array: 𝒊 = 𝑮7𝒚, 𝑮′ is Inverse Fourier Matrix 𝒛𝒋 = 𝒃𝒋 𝒊 = 𝒃𝒋 𝑮7𝒚

90 180

𝑮 Divide 𝒃𝒋 into segments 𝑮

𝒃𝒋

90 180

𝒃𝒋 =

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SLIDE 16
  • 1. How do we create multi-armed beams?
  • 2. What is the best choice of multi-armed

beams to minimize the number of measurements?

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Signals traveling along different paths can cancel each other

Why do we need to choose the beams carefully?

AP Client

30 60 90 120 150 180

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SLIDE 18

AP

Client

60o

Hashing

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Best Choice of Multi-Armed Beams

0o 30o 60o 90o 120o 150o 180o Bins: 1 2 3 4 Spatial Directions

  • Pick multi-armed beams to create random hash functions
  • Estimate the true direction using voting

Voting

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SLIDE 19

Theorem

(Informal)

  • Assuming:
  • N possible directions
  • K signal paths
  • Our algorithm finds the optimal beam

alignment in 𝑃 𝐿 log 𝑂 measurements.

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Experimental Results

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Implementation and Evaluation

Built a Millimeter Wave Radio with a Phased Array.

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1 10 100 1000 10000 50 100 150 200 250

Reduction in Search Time

Phased Array Size

Agile-Link vs Exhaustive Search Agile-Link vs 802.11ad

Our system vs. Exhaustive Our system vs. 802.11ad

Number of Measurements

Number of Potential Directions (N) Reduction in the Number

  • f Measurements

Our system requires orders of magnitude fewer measurements

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Beam Alignment Latency

Number of Directions 802.11ad 802.11ad

with our algorithm

16 1ms 0.5ms 64 4ms 0.8ms 128 106ms 0.9ms 256 310ms 1.0ms

Achieved fast beam alignment (less than 1ms)

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Beam Alignment Accuracy

Agile-Link performs much better than Exhaustive search and 802.11ad

0.2 0.4 0.6 0.8 1 1 2 3 4 5 6 7 8

CDF SNR Loss (dB)

Agile-Link 802.11ad Exhaustive Search

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Related Work

  • Past Work on Beam Alignment:

[D. Araujo EUSIPCO’14, J. Kim Jour. Communications’14, B. Li Trans. Wireless’13, Y. M. Tsang Globecom’11, J. Wang Communications’09, W. Yuan PIMR’15, L. Zhou PIMRC’12, D. Ramasamy Allerton’12, A. Alkhateeb IEEESP’14, B. Gao. IET’14, B.Li Trans. Wireless’13, T. Nitsche ENET’15, T. Nitsche Infocom’15,etc]

  • Past Work on mmWave Channel Studies:

[C. R. Anderson Trans. Wireless’04, S. Collonge Trans. Wireless’04, S. Rangan IEEE’14, M. Smulders Trans on Ant.’09, J. Violette NASA report, J. Comm. ’02, S. Sur SIGMETRIC’15, A. Saeed VTC’16, X. Tie PAM’11, etc]

  • Past Work on using Sparsity:

[E. Eltayeb GLOBESIP’15, A. Alkhateeb J. IEEE’14, B. Gao’ IET14, D. Ramasamy, IEEE’14, etc]

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Conclusion

  • Establishing communication links in millimeter

wave networks is challenging due to directionality.

  • Agile-Link: millimeter wave system that can quickly

establish a link without having to scan the space.

  • Exciting time for millimeter wave networks!
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SLIDE 27

Omid Abari

Haitham Hassanieh, Michael Rodriguez , Mohammed Abdelghany, Dina Katabi, and Piotr Indyk

Fast Millimeter Wave Beam Alignment