Docstoc

Evaluation of Live Streaming Multicast over Dynamic Overlay in

Document Sample
Evaluation of Live Streaming Multicast over Dynamic Overlay in  Powered By Docstoc
					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.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:15
posted:9/2/2011
language:English
pages:22