Towards an Open Source IEEE 802.11p Stack Bastian Bloessl - - PowerPoint PPT Presentation

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Feb 01, 2023 9 likes •214 views

Towards an Open Source IEEE 802.11p Stack Bastian Bloessl <bloessl@ccs-labs.org> Computer and Communication Systems Group, University of Innsbruck, Austria February 2014 FOSDEM SDR Dev Room Brussels, Belgium Outline

SLIDE 1

Bastian Bloessl <bloessl@ccs-labs.org>

Computer and Communication Systems Group, University of Innsbruck, Austria February 2014 ∙ FOSDEM ∙ SDR Dev Room ∙ Brussels, Belgium

Towards an Open Source IEEE 802.11p Stack

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Outline

▪ Introduction

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 2

▪ IEEE 802.11p Transceiver ▪ Applications

Wireless Measurement and Experimentation

SLIDE 3

Improved SDR Platforms

▪ {B,N}210 ▪ HackRF ▪ BladeRF

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 3

▪ VOLK ▪ Async. Messages ▪ OFDM Reference Design GNU Radio Hardware ▪ DVB-T ▪ LTE ▪ WiFi Standards

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SDR in EE and CS

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 4

▪ Signal processing ▪ Receiver design ▪ Signal propagation Electrical Engineering ▪ Network protocols ▪ Network simulation ▪ Security / Privacy Computer Science Example: Vehicular Networks

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Vision: Vehicular Ad Hoc Networks

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 5

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IEEE 802.11p Standard

▪ Standardized in 2011 ▪ Dedicated spectrum ▪ Adaption of WiFi

▪ OFDM ▪ 64 subcarriers ▪ 10 MHz bandwidth

▪ Problem:

▪ Designed for indoor environments

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Pilots Data

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Current Experimental Platforms

▪ Prototypes

▪ Cohda MK2

▪ Adapted WiFi cards

▪ Unex DCMA-86P2 ▪ Atheros

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 7

Limited Information / Blackbox

SLIDE 8

IEEE 802.11p Transceiver

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 8

Bastian Bloessl, Michele Segata, Christoph Sommer and Falko Dressler, "Towards an Open Source IEEE 802.11p Stack: A Full SDR-based Transceiver in GNURadio," Proceedings of 5th IEEE Vehicular Networking Conference (VNC 2013), Boston, MA, December 2013, pp. 143-149.

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Transceiver Design

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 9

▪ Layered Design ▪ Hierarchical Blocks ▪ Extendable

▪ Wireshark ▪ Linux TCP/IP

▪ No changes to FPGA

App MAC

Socket MAC OFDM USRP TX USRP RX

PHY HW

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Application Interface

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▪ Connect to SDR via TCP/UDP sockets

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Interoperability

▪ IEEE 802.11a/g

▪ MacBook Pro ▪ Intel Ultimate N6300 ▪ Air Live X.USB

▪ IEEE 802.11p

▪ Cohda Wireless MK2 ▪ Unex DCMA-86P2 Atheros-based

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 11

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Limitations of GPP-based Platform

▪ RTS / CTS ▪ Acknowledgments ▪ Duration Field

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 12

Ping Tun / Tap GNU Radio

100ms delay

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Carrier Sensing and Channel Access

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 13

A. Puschmann, P. Di Francesco, M. A. Kalil, L. A. DaSilva, and A. Mitschele-Thiel, “Enhancing the Performance of Random Access MAC Protocols for Low-cost

SDRs,” in 8th International Workshop on Wireless Network Testbeds Experimental Evaluation and Characterization (WiNTECH 2013). Miami, FL: ACM, September 2013.

Noise OFDM Frame 32.9us

▪ CSMA on PC has too high delay ▪ CSMA on FPGA is feasible

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Applications

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 14

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Fuzzing

▪ Form of penetration testing ▪ Send random, cluttered, non-standard frames ▪ See what happens to the device / driver / firmware

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack

„ If fuzzing doesn‘t solve your problem, you‘re not doing enough of it “

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Privacy and Fingerprinting

▪ EE

▪ Channel features ▪ Characteristics of analog HW

▪ CS

▪ Traffic patterns (when, where, packet size, …) ▪ MAC address / temporary identity

▪ SDR

▪ Implementation details of chip / firmware / driver

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4242 2323

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Enabling Realistic Simulations

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Network simulation ▪ Coherence bandwidth ▪ Coherence time ▪ Channel taps Measurement results ▪ Frame Error Curves ▪ OFDM interference + gr-ieee802-11 = channel models

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…in Conclusion

Bastian Bloessl – Towards an Open Source IEEE 802.11p Stack 18

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Conclusion

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▪ SDR-based IEEE 802.11p OFDM transceiver ▪ Modular and extensible ▪ Many applications ▪ Open Source

▪ http://www.ccs-labs.org/projects/wime/