a novel social cluster-based p2p framework for integrating vanets with the internet chien-chun hung...

A NOVEL SOCIAL CLUSTER-BASED P2P FRAMEWORK FOR INTEGRATING VANETS WITH THE INTERNETChien-Chun HungCMLab, CSIE, NTU, Taiwan

OUTLINE

• Introduction • Social cluster-based overlay structure• Lifetime-aware flooding scheme• Connectivity-aware retrieval scheme• Performance Evaluation• Conclusions

INTRODUCTION

• Non-safety related applications in VANETso Improve driving comforto Provide interesting entertainment services

• Two different types of communications:o Inter-Vehicle Communicationo Roadside-to-Vehicle Communication

• Two important elements defined in VII (Vehicle Infrastructure Integration):o RSU(Road Side Unit)o OBU(On Board Unit)

INTRODUCTION

• Peer-to-peer(P2P) system:o Efficiently access different types of datao Leverage each peer’s resourceo Reduce the load of original content provider

• Main components of P2P system:o Resource discovery schemeo Resource retrieval scheme

INTRODUCTION

• Goal: To design a P2P framework for hybrid network(VANET and Internet)o Fixed peer: original peers in thee Interneto Mobile peer: moving vehicles

oChallenge: Enable mobile peers to request and retrieve resource efficiently according to connectivity and environment

INTRODUCTION

• Framework: Interest-based clustering to group similar peers into a cluster:

1.Social cluster-based overlay structure1. To eliminate discovering overhead through the RSU

2.Lifetime-aware flooding scheme To eliminate request storm among mobile peers

• Connectivity-aware retrieval scheme Take lifetime and bandwidth into consideration to select the best peer

OUTLINE


SOCIAL CLUSTER-BASED OVERLAY STRUCTURE

• Goal: to eliminate the overhead of finding mobile peers.o Group mobile peers and fixed peers into clusters.o Peers with similar interests are group into a cluster.

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• Interest-based intra-cluster constructiono One fixed peer and several mobile peerso Mobile peer picks the cluster whose cluster head has the most

similar interest with ito Fixed peer acts as the cluster head and maintains file indexes of its

cluster


• Small-world-based inter-cluster constructiono Random walk to reach into different clusterso To increase the ratio of resources that can be found

• Peers can use overlay to effectively discover resources by requesting the cluster.

OUTLINE


LIFETIME-AWARE FLOODING SCHEME• Social cluster-based overlay

o Enable mobile peers to discover resources in clusters (through RSUs)

• Lifetime-aware flooding scheme Help mobile peers to efficiently discover resources

through VANETS

• Connection lifetime must be taken into consideration.

LIFETIME-AWARE FLOODING SCHEME

OUTLINE


CONNECTIVITY-AWARE RETRIEVAL SCHEME

• If a mobile peer requests too many blocks at once, it might waste bandwidth.

• The path quality between two peers must be considered in order to decide how to retrieve data.o Path lifetimeo Path bandwidth

CONNECTIVITY-AWARE RETRIEVAL SCHEME

OUTLINE


PERFORMANCE EVALUATION

• Network simulator 2 (NS2)• Geographic Information System (GIS)• 200 fixed nodes in 3000m * 3000m• 802.11n standard MAC protocol• Transmission range: 250m• Transmission rate: 27 Mb/sec• 83 kinds of data, 31005 files

PERFORMANCECOMPARISON SCHEMES

• Gnutella • Interest-based P2P scheme• Network-based P2P scheme• CarTorrent• Social Cluster-based P2P scheme

PERFORMANCE EVALUATIONQUERY HIT RATIO VS. RSU NUMBERS

• 200 mobile peers• Each has 50 cached files

PERFORMANCE EVALUATIONRATIO OF RETRIEVING FILES VS. NUMBER OF RSUS

PERFORMANCE EVALUATIONMESSAGE OVERHEAD VS. NUMBER OF RSUS

PERFORMANCE EVALUATIONQUERY HIT RATIO VS. CACHED FILES

OUTLINE


CONCLUSIONS

• Design a P2P system that can integrate VANETs and the Interneto Social cluster-based overlay structureo Lifetime-aware flooding schemeo Connectivity-aware retrieval scheme

• Our work achieves higher discovering rate and retrieving speed than existing schemes.

a novel social cluster-based p2p framework for integrating vanets with the internet chien-chun hung...

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