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Evaluation of Live Streaming Multicast over Dynamic Overlay in

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									Evaluation of Live Streaming
Multicast over Dynamic Overlay
in Urban VANETs

         Yi-Ling Hsieh
          MBL, NCTU
          2011/04/27
Outline
   Introduction
   Related works
   Model of dynamic overlay
   Evaluation and discussion
   Conclusion
   Future work
   References
Introduction
   Emerging of vehicular communication and application
       Standards such as DSRC, WAVE, 802.11p
       Vehicular safety
       Infotainment
   Charateristics of VANETs
       High mobility (and result in high packet loss)
       Vehicles move in pre-defined route (map)
   Literatures for multimedia distribution in VANETs
       Streaming QoS in vehicular environments
       Multicast
       Streaming over P2P and overlay networks
Introduction
   Scenarios of vehicular environments
       Free space
       Highway (or straight road)
       Urban (or street)
            (not yet further studied in literatures of multimedia
             distribution)
   Urban environment
       Many road intersections and obstacles
       Packet loss rate is much higher due to routing is
        easily broken and rebuild
         Introduction
   Our focus scenario
       Multicast overlay
            Overlay multicast vs. network-layer multicast: overlay
             multicast offers the flexibility of node capability for the
             protocol
       Interested vehicles (called group members) form a
        multicast tree
            The multicast source node is the tree’s root node
            The group members are organized as an overlay
       Since routing is easily broken due to urban
        environment, organize a small group of nodes by
        overlay is more flexible
Related works
   Overlay multicast in MANETs
       Static overlay or dynamic overlay
       Tree or mesh
       Low speed (1~10m/s, 3.6~36km/hr)
           Need further study if applied in VANETs
            (5~25m/s, 18~90km/hr)
Related works
   Existing literature of multimedia distribution
    in VANETs:

   CodeTorrent [1] and NCDD [2]
       They utilized the random network coding
        technique for data dissemination in VANETs
       However, it requires all nodes periodically
        broadcast pieces information and may consume
        much time to collect enough pieces to decode if
        the multicast group size is small
Related works
   SMUG[3]
       Every node may dynamically be selected as
        a forwarder, and its transmissions are
        scheduled by color-filtering rule
       However, if the SMUG-capable nodes are
        not dense enough, the forwarding paths
        are easily broken. Besides, SMUG can only
        be applied in TDMA-based ad hoc
        networks.
Related works
   Multimedia data delivery through an overlay
    over VANETs
       N.N. Qadri et al. [4] proposed a series of
        evaluation papers
            impact of radio models and mobility models over overlay
             networking in VANETs
            improvement by video error resilience techniques such as
             MDC and FMO.
       the overlay topology was fixed, even though
        nodes are mobile. And only 7 nodes.
Related works
   Out contributions
       Evaluate the improvement of using
        “dynamic” overlay in high speed, easily
        routing broken VANETs (firstly studied)
       The impact of considering obstacle in
        simulation for urban VANETs (firstly
        studied)
       Evaluate the improvement of using
        multiple parents mesh
Model of dynamic overlay in
urban VANETs
Model of the overlay structure
   Tree
       1 child has only 1 parent
       If the routing fail, the child and all
        offspring can not receive any streaming
            improvement: multiple parents (as mesh)
   Mesh
       1 child has 2 parents
            Pa: current parent
            Pb: last parent
Model of dynamic overlay
   If QoS of parent is low, or route fail
    between the parent, change to a new
    parent

   Probe for a better QoS and less-distant
    parent
Model of dynamic overlay
   Probe procedure
       We use Continuouty Index, CI, as QoS
        value: ratio of streaming packets received



       Probe for less-distant nodes
Model of dynamic overlay
   Probe procedure
       For mesh (1 child has 2 parents)
            Current parent  become last parent (Pb)
            New parent  become current parent (Pa)
Evaluation and discussion
   Simulator: Qualnet 5.0
   Transmission power:19.3 dBm (~625m)
   Receiver power:58.4 dBm
   Node movment trace generator: VanetMobiSim 1.0
       Node speed: [5 m/s, 25 m/s]
       IDM-LC mobility (intelligent driving model - lane changing)
        model
   Map: Grid 1000mx1000m, section 100m
   Underlying routing protocol: Location Aware Routing
    (LAR)
   Packet generation: CBR as 64kbps, 128kbps, 256kbps
   Movement table exchange interval: 5s
   Probe interval: 10s
       Evaluation and discussion
       0.95
                                d0b0
       0.85
                                                    d0b1
       0.75
  CI




                                                    d0b1_2p
       0.65                                         d1b1_1p
       0.55                                         d1b1_2p
       0.45
              5          10      15        20
                   Number of group nodes



                              d: dynamic
Fig 1. CI under 64kbps
                              b: blocking obstacles simulated
                              2p: 2 parents mesh
       1
     0.8
                                       d1b1_1p@64kbps
     Evaluation and discussion
     0.6
     0.4
                       d1b1_1p@128kbps
                                       d1b1_1p@256kbps
     0.2
       0
           5    10      15      20

       1
     0.8
                                       d1b1_2p@64kbps
     0.6
                                       d1b1_2@128kbps
     0.4
     0.2                               d1b1_2p@256kbps
       0
           5    10      15      20

                             d: dynamic
Fig 2. CI comparison
                             b: blocking obstacles simulated
among 64,128,256 kbps
                             2p: 2 parents mesh
                      1.8
                      1.6
                      1.4                                       d0b0
                      1.2
                                                                d0b1
          Delay (s)
                        1
                                                                d0b1_2p
                      0.8
                      0.6                                       d1b1_1p
                      0.4                                       d1b1_2p
                      0.2
                        0
                            5       10        15        20
                                Number of group nodes


Fig 3. Total delay under 64kbps
                                          d: dynamic
                                          b: blocking obstacles simulated
                                          2p: 2 parents mesh
Evaluation and discussion
  1
     0.9
     0.8
                                                    64kbps
     0.7
CI




                                                    128kbps
     0.6
                                                    128kbps(RD)
     0.5
     0.4
     0.3
           100           200             400
                 Road section interval


                                           RD (density on road):
                                           Sec 100:100 nodes
                                           Sec 200:54 nodes
                                           Sec 400:21 nodes
Conclusion
   We firstly studied the improvement of
    using “dynamic” overlay in high speed,
    easily routing broken VANETs, and the
    impact of considering obstacle in
    simulation for urban VANETs
   We also evaluate the improvement of
    using multiple parents mesh
References
1.   U. Lee, J.-S. Park and M. Gerla, “CodeTorrent: a content
     distribution using network coding in VANET,” in Proc. of First
     ACM Workshop on Decentralized Resource Sharing in Mobile
     Computing and Networking, pp. 1-5, 2006.
2.   Joon-Sang Park et al. , "Emergency related video streaming in
     VANET using network coding," in Proc. of the 3rd
     International Workshop on Vehicular Ad Hoc Networks, ACM,
     pp. 102-103, 2006.
3.   F. Soldo, C. Casetti, C.-F. Chiasserini, and P. Chaparro,
     “Streaming media distribution in VANETs,” in Proc. of IEEE
     GLOBECOM, 2008.
4.   N.N. Qadri, M. Fleury, M. Altaf, M. Ghanbari, "Multi-source
     video streaming in a wireless vehicular ad hoc network," IET
     Communications, vol. 4, pp. 1300-1311, 2010.

								
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