Mac performance analysis for vehicle to infrastructure communication
1 / 14

MAC Performance Analysis for Vehicle to Infrastructure Communication - PowerPoint PPT Presentation

  • Uploaded on

MAC Performance Analysis for Vehicle to Infrastructure Communication. Tom H. Luan*, Xinhua Ling , Xuemin (Sherman) Shen* *BroadBand Communication Research Group University of Waterloo. §. Research In Motion. §. Outline. Introduction to Vehicular Network Model of MAC in V2I communication

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'MAC Performance Analysis for Vehicle to Infrastructure Communication' - otis

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Mac performance analysis for vehicle to infrastructure communication

MAC Performance Analysis for Vehicle to Infrastructure Communication

Tom H. Luan*, Xinhua Ling , Xuemin (Sherman) Shen*

*BroadBand Communication Research Group

University of Waterloo


Research In Motion


Outline Communication

  • Introduction to Vehicular Network

  • Model of MAC in V2I communication

  • Simulation

  • Conclusion

Why vehicular networks
Why Vehicular Networks ? Communication

  • Internet becomes an essential part of our daily life

    • Watch video on Youtube; order literature on Amzone; catch the final moments of an eBay auction …

  • Americans spend up to 540 hours on average a year in their vehicles (10% of the waking time)

  • Internet access from vehicles is still luxury

  • Vehicular Network

    • To provide cheap yet high throughput data service for vehicles on the road

V2v and v2i communications
V2V and V2I Communications Communication

Vehicle to RSU (V2R or V2I)

  • Infotainment: Internet access, video streaming, music download, etc.

  • MAC throughput performance evaluation of V2I communication

Vehicle to Vehicle (V2V)

RSU (roadside unit)

Standard and research efforts
Standard and Research Efforts Communication

  • IEEE drafts 802.11p standard to permit vehicular communication

    • 802.11a radio technology + 802.11e EDCA MAC

    • Multi-channel: 6 service channels + 1 control channel

  • Drive-thru Internet

    • Using off-the-shelf 802.11b hardware, a vehicle could maintain a connection to a roadside AP for 500m and transfer 9MB of data at 80km/h using either TCP or UDP

Image from

[1] J. Ott and D. Kutscher, "Drive-thru Internet: IEEE 802.11 b for 'automobile' users," in IEEE INFOCOM, 2004

Standard and research efforts cont d
Standard and Research Efforts (cont’d) Communication

  • CarTel in MIT [2]

    • City-wide experiment showing the intermittent and short-lived connectivity, yet high throughput while available

  • Small scale network without considering MAC

    • Link layer and transport layer performance

  • What if a great number of vehicles moving fast?

[2] V. Bychkovsky, B. Hull, A. Miu, H. Balakrishnan and S. Madden, "A measurement study of vehicular internet access using in situ Wi-Fi networks," in ACM MobiCom, 2006

Problem statement
Problem Statement Communication

  • MAC performance evaluation for fast-movinglarge scale vehicular networks

  • We consider 802.11b DCF

    • Used by most trail networks, e.g., Drive-thru

    • Compatible to WiFi device (e.g., iPod Touch)

    • The basis of 802.11p MAC

Network model
Network Model Communication

  • Perfect channel without packet loss and errors

  • Saturated case: nodes always have a packet to transmit

  • Multi-rate transmission according to the distance to RSU

  • Spatial zones: the radio coverage of one RSU is divide into Z = {0, 1, …, N} zones according to node transmission rate

  • p-persistent MAC: nodes transmit with a constant probability pz for different zone n in Z

  • Mobility Model

    • Sojourn time of vehicles in each zone n is geometrically distributed with mean tn

    • Within a period , vehicle moves from zone n to n+1 with the probability /tn, and no change with the left probability

Markov model of vehicle nodes
Markov Model of Vehicle Nodes Communication

  • 2D Markov chain embedded at the commencement of the backoff counter countdown

  • Upon the decrement of backoff counter, vehicle may either move to the next zone or stay in the original zone

  • When coming into a new zone, different transmission probability is applied

  • Each node can be represented by {z(t), b(t)}

    • z(t): zone the vehicle is current in at time t

    • b(t): the value of backoff counter of the node at time t

Simulation setup
Simulation Setup Communication

  • Radio coverage of RSU is 250m, which is divided into 8 zones

  • By default, 50 vehicles move at constant speed with v = 80 km/h

  • When arriving at the end of the road session (zone N), vehicles reenter zone 0 and start a new iteration of communication

  • Two schemes

    • Equal contention window (transmission probability p) in all zones

    • Differential contention window in zones

Nodal throughput in each zone n
Nodal Throughput in Each Zone n Communication

sn =

Nodal Throughput in Each Zone

Average pkt length in each trans.

Mean interval between consecutive trans.

Integrated Throughput


S = ∑


Where Xn is the node population in zone n

  • Using equal CW in all zones would suffer from performance anomaly

Increasing velocity
Increasing Velocity Communication

  • With enhanced node velocity, nodes in front zones have higher throughput than the back zones

    • The small CW in zone 4 benefits the following zones

  • System throughput reduces when velocity increases

Conclusion Communication

  • Throughput performance evaluation of DCF in the vehicle to infrastructure communication

  • Increase the velocity would reduce the system throughput

  • Future work

    • Optimal design of DCF (contention window)

    • QoS provision with call admission control etc.

Question and answers

Question and Answers ? Communication

Thank you !