Vehicle to vehicle communication in COM2REACT (Alberto Los Santos)

Vehicle to vehicle communication in COM2REACT

© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal

Alberto Los Santos AransayNetworked Vehicles Division - TELEFÓNICA I+D

Date: January 30, 2008

Communication challenges in Intelligent Transportation Systems

Tel Aviv, January 30, 2008

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01 Introduction

- COM2REACT objective

- VANETs and requirements

02 V2V communication module

- Technology selection

- Components description

03 R&D Results

- Field tests

- Simulations

04 Conclusions

Index

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01 Introduction






03 R&D Results

- Field tests

- Simulations

04 Conclusions

Index

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Introduction COM2REACT objective

The guideline concept in COM2REACT is the Virtual Sub-Centre (VSC).

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The VANET (Vehicular Ad-hoc Network) is the communication layer that supports all VSC functions. This network is composed of different vehicles communicating between themselves, using the V2V communication system.

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Introduction VANETS

VANETs (Vehicular Ad-hoc Networks) :

Specialisation of mobile ad-hoc networks (MANETs).

Common characteristics of MANETs are present in VANETs too. — Multihop communication, dinamic topology, lack of a central entity,

auto-configuration and self-healing are the principal issues of these networks.

However, automotive ad-hoc networks behave in different ways than MANETs. — Driver behaviour.

— Constraints on mobility and high speeds.

— Rapid but somewhat predictable topology changes.

— Small effective network diameter.

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COM2REACT requirements Technical and business

Considering a Hazard scenario : Physical layer:

— Omnidirectional long distance communication (~ 700 meters).— Robustness in difficult propagation situations (high relative

velocities, NLOS…)— High and stable bandwidth for V2V communication.— The system must work in ad-hoc mode, without infrastructure.

— Low delay and Support of dense networks and changing topology.

Beside these technical requirements, also some business requirements play an important role:— Availability of its components in the market. — Also, COM2REACT will focus on the usage of low-cost hardware

components.

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01 Introduction






03 R&D Results

- Field tests

- Simulations

04 Conclusions

Index

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Technology selection State of the Art

C2R consortium is aware of other work done:

Consortiums and projects:

Papers and documents.

Communication technologies:

— 802.11a/b/g, 802.11p, DSRC, WIMAX, MBWA, CALM…

But, in order to demonstrate the VSC usefulness, an actual solution for V2V communication is needed.

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-> 802.11b?

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Technology selection 802.11b

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802.11b 802.11p

Bandwidth 11 Mbit/s 54 Mbit/s

Band 2.4 GHz 5.9 GHz

Latency 50 ms 50 ms

Typical range30 – 50 meters

(indoor)400 meters

StatusActual but, feasible?

Future

802.11b vs 802.11p— 802.11b is the most commonly used version of the IEEE

WLAN standard in wireless networks (2.4GHz WiFi).

— 802.11p is a draft amendment to the IEEE 802.11 standard for enabling wireless access in the vehicular environment.

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V2V communication module Initial tests

Initial tests with 802.11b:

The goal of these tests was to check the maximum communication distance with 802.11b standard wifi cards (Senao NL-5354MP PLUS ).

— After different tests and situations, the maximum range was about 250 meters setting the system to its maximum power (100mw RF power).

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-> Need for an extended-range solution

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V2V communication module Components description

802.11b based V2V communication module with extended range:

Components:— Ubiquiti SR2 WIFICARD

(máx. 400 mW)

— 9 dBi ANTENNA

— ROUTERBOARD 532A

— SERIAL GPS

Software:— Debian MIPS distribution

— Madwifi driver

— Iperf

— OLSR

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01 Introduction






03 R&D Results

- Field tests

- Simulations

04 Conclusions

Index

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R&D Results

The work has been divided into:

Field Tests:

— Different situations and scenarios.

Simulations:

— Complementing the results obtained in the real tests.

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Field Tests Inter-urban scenario (1-hop communication)

In a straight 3km. long secondary road:

— Speed influence.

— Power vs. distance.

— 802.11b/g comparison.

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Field Tests Inter-urban scenario (multi-hop communication)

In the same scenario presented before:

Communication with 3 vehicles:

— Throughput and hops vs distance.

— Route changes study.

— Influence of multihop.

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Field Tests Urban scenario (LOS and NLOS situations)

The system has been tested in urban scenarios:

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NLOS situations

LOS situations

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Simulations HI tunning

To study the HI parameter in the OLSR protocol:

The scenario consists in a string of 14 vehicles driving in the same direction, another vehicle, called vehicle0, drives in opposite. The relative speed of the vehicle string and vehicle0 is 180 Kmph.

Four different Hello Intervals values have been evaluated: 0.5, 1, 1.5 and 2 seconds.

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PDR[%]

Av. Del.[sec]

Av. Thr. [Mbps]

Overhead [Kbps]

NRO [%]

Avg. Hops

0.5 11,64 0,57 0,95 19,96 2,14 1,33

1 12,1 0,62 0,99 12,18 1,25 1,38

1.5 11,26 0,71 0,93 9,47 1,06 1,48

2 11,08 0,71 0,91 8,25 0,94 1,5

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Simulations Inter-urban scenarios

1-hop communication

Measuring:

— Delay vs distance and speed.

— Throughput vs distance and speed.

— Connection distance and connection time.

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Simulations Inter-urban scenarios

Multi-hop communication:

Measuring:

— Hop number, delay and throughput vs distance.

— Delay and throughput versus hop number.

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Simulations Complementary results

Urban scenario:

— different vehicle density: 50, 100 and 150 vehicles/km2.

— different network load : 1000, 2000, 4000 and 8000 connections.

— Measuring: Delay, hops, PDR, Routing Load, vs Connections.

— Comparing RTS/CTS and HI = 0.5 and 1 second.

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01 Introduction






03 R&D Results

- Field tests

- Simulations

04 Conclusions

Index

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Conclusions V2V communication in COM2REACT

The main conclusion is that the 802.11b module adopted is suitable for V2V communication, satisfying COM2REACT requirements.

Field tests have shown inter-vehicle communications bearing up to 260km/h with an average bandwidth greater than 4 Mbit/s.

Range in interurban scenarios with LOS is larger than 3 Km.

However, 802.11b is highly influenced by the environment. In urban scenarios (LOS), multipath propagation reduces the communication distance to 300 meters.

In scenarios with buildings between the vehicles (NLOS), the communication can’t be ensured.

In multihop communications distance is increased considerably, but this produces a high bandwidth reduction and a strong delay growth due to the shared medium.

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Conclusions Future

Nowadays, V2V communications are a major line of work and research.

New technologies will be developed (i.e. 802.11p) and routing algorithms, that will support the future vehicular services.

But just now we can show COM2REACT and VSC benefits thanks to an 802.11b based V2V communication module.

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For more information:Alberto Los Santos Aransay P.T. Walqa – Edificio Ramón y CajalNetworked Vehicles Division Huesca – Spain Telefónica I+D [email protected] :: +34 974 21 55 00

mailto:[email protected]

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