(Slides) Video Ads Dissemination through WiFi-Cellular Hybrid Networks

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Hanano, H., Murata, Y., Shibata, N., Yasumoto, K., and Ito, M.: Video Ads Dissemination through WiFi-Cellular Hybrid Networks, Proc. of the 7th IEEE Int'l. Conf. on Pervasive Computing and Communications (PerCom 2009), pp. 322-327, DOI:10.1109/PERCOM.2009.4912787 (Mar. 2009).

In this paper, we propose a method for video ads dissemination through a hybrid network consisting of WiFi and cellular networks, in order to provide timely delivery of video ads with preferred content to users according to the users' contexts. In recent years, video download/streaming services for cellular phones have already become popular. Among various video delivery services, a service for disseminating video ads according to the users' contexts is expected to achieve high advertising effects. However, context-aware video ads dissemination will consume large bandwidth since the size of video ad is rather large and the same ad is required at different time from various users. We propose a new video ads dissemination method for mobile terminals which utilizes both WiFi and cellular networks. In the proposed method, a file of video ad is divided into pieces and each node exchanges the pieces with neighbor nodes using WiFi ad hoc communication so that the usage of cellular network is reduced. In order to make the method works effectively for a large number of nodes, we propose an algorithm where mobile nodes autonomously and probabilistically decide their actions without a central control. Through simulations, we confirmed that our method reduces cellular network usage by about 93% compared with a case that all nodes download video ads via cellular network, and works effectively in cases with a large number of nodes and high mobility.

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(Slides) Video Ads Dissemination through WiFi-Cellular Hybrid Networks

  1. 1. Video Ads Dissemination through WiFi-Cellular Hybrid Network (revised) Hiroshi Hanano1, Yoshihiro Murata2, Naoki Shibata3, KeiichiYasumoto1 and Minoru Ito1 1NaraInstituteofScienceandTechnology 2HiroshimaCityUniversity 3ShigaUniversity
  2. 2. Organization 1. Background 2. RelatedWork 3. Problem Formulation 4. Proposed Algorithm 5. Evaluationthrough Simulations 6. Conclusion 2Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  3. 3. Demand for Context-Aware Video Ad Dissemination • Video deliveryto mobile terminals has alreadybecome common – Videoadvertisementdissemination now attractingpublicattention • Many studies forobtaining user contexts(situation, etc) withsensors,userdata(profiles,schedules,etc),andsoon • Context-aware video ad dissemination – Muchhigheradvertisementeffectthanwithoutcontext- awareness 3 Movie trailers Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  4. 4. Challenges • Contexts are differentamong users, change overtime – Eachvideoadshouldbedeliveredtousersatdifferenttime 4 → larger data amount transferred via cellular network → need to consider influence to other cellular services → number of ads may be restricted We need a dissemination method which does not overload cellular network Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  5. 5. Goals • Distribute communication load forvideo ad dissemination from cellularnetwork to WiFi network as much as possible 5 Cellular Network load WiFi(Ad-hoc) Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  6. 6. Organization 1. Background 2. RelatedWork 3. Problem Formulation 4. Proposed Algorithm 5. Evaluationthrough Simulations 6. Conclusion 6Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  7. 7. Complementing Cellular Network with MANET – Somemobileterminalsincongestedcellareause lightloadedcellviaMANET 7 Hongyi, W., Chunming, Q., Swades, D. and Ozan, T.: ”Integrated Cellular and Ad Hoc Relaying Systems:iCAR,” Proc. of ICC 2001 It does not reduce overall data amount transferred for video ads dissemination Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  8. 8. Introducing BitTorrent into MANET • Purpose:efficientfile exchangeamong mobile terminals – RealizedBitTorrentmechanismonMANET – Evaluationdoneintermsof mobilityandchunksizes – Showrobustnessagainstnetworkpartition 8 S. Rajagopalan. and C.-C. Shen: ”A Crosslayer Decentralized BitTorrent for Mobile Ad hoc Networks,” Proc. of MOBIQUITOUS 2006 It only uses MANET, and thus achieves poor performance on data acquisition ratio/time Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  9. 9. Organization 1. Background 2. RelatedWork 3. Problem Formulation 4. Proposed Algorithm 5. Evaluationthrough Simulations 6. Conclusion 9Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  10. 10. Assumptions • Manyuserswithmobilephonesinurbanarea – PhonescanusebothcellularandWi-Fi(ad-hocmode)networks • Terminalautomaticallysets,accordingtouser’scontext: – Videoadcontents(byfilenames) – ReceptionDeadlineforeachcontent 10 ex) Context: Bob has a plan to go to a movie after work Contents: Trailers of movies currently running Deadline: Time when work finishes Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  11. 11. Target Problem (see PerCom09 paper for more formal description) • Input – Videoadswithdeadlinesrequestedbyeachmobilenode • Output – Actionsofmobilenodesateachmoment • Download, Broadcast, or Receive (part of) data • Constraints – Cellulartowercapacity(Nconnectionscanbeadmitted) – Cellularnetworkbandwidthperconnection – Wi-Firadiorangeofeachmobilenode – Wi-Fibandwidthsharedbyallnodesineachradiorange – Receptiondeadlineofeachcontent • Objectivefunction – Minimizedataamounttransferredthroughcellularnetwork 11Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  12. 12. Organization 1. Background 2. RelatedWork 3. Problem Formulation 4. Proposed Algorithm 5. Evaluationthrough Simulations 6. Conclusion 12Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  13. 13. Approach • File division (likeBitTorrent) – Divideeachadcontentintochunkswithfixeddatasize – Everynodecancontributeaddisseminationinfairmanner • Utilizationof WiFi (ad-hoc mode) – Reduceloadincellularnetwork bylettingnodesexchangechunksthroughWi-Finetwork • Fully distributed algorithm – Eachterminaldecidesitsactionbasedonlyon informationof neighbornodes – Scalabletonumberofnodes,numberofcontents,etc 13Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  14. 14. Possible Actions Taken by Mobile Terminal • Downloada chunk through cellularnetwork • Broadcast a chunk through WiFi (ad-hoc mode) network • Waitto receive a chunk through WiFi network 14Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  15. 15. Algorithm for Action Decision • Eachnode takes an actionfor global benefit – Foreachchunk,onlyoneterminalshoulddownloadit – Ineachradiorange,weshouldavoidtwoormoreterminals broadcastingthesamechunk • Flow of proposed algorithm 15 Info Gathering Part Gather neighboring info Action Decision Part Select a chunk Take an action Categorize chunks/compute impact of chunks Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  16. 16. Information Gathering Part • Informationrequired to decide action – DemandInfo.:whichcontentseachnoderequires – ChunkInfo.:whichchunkseachnoderetains • CreateNeighbor Table by exchanginghello messages – Eachnodeperiodically(ex.30s)broadcasthellomessage includingdemandinformationandchunkinformation 16 a1 a2 a3 …A, B Demand Info. Chunk Info. :retain :no Hello Message a1 a2 a3 …A, C b1 b2 b3 …B, D a1 a2 a3 …A, D n1 n2 n3 ↑Terminal ID Neighbor Table Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  17. 17. Action Decision Part 1. Select a chunk foraction – Categorizechunks • Chunks ALREADY obtained broadcast via WiFi • Chunks NOT obtained download from cellular – Impactcomputation • Prioritize chunks by putting impact values – Rouletteselection • Select a chunk by roulette 2. Takean actionfor the selectedchunk – Forbroadcast,weleteachnodetakeactionat probability b toavoidcollision 17Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  18. 18. Action Decision Phase –Categorizing Chunks– • C1: Chunks to be downloadedfrom cellular – Nodewantsa chunk,butnoneighbornodesretainit • C2: Chunks to be broadcast through WiFi – Noderetainsa chunk,andsomeofneighbornodeswantit • C3: Other chunks – Nodedoesnottakeanyactiontothosechunks 18 Node under consideration Node under consideration Neighbor nodes Neighbor nodes Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  19. 19. Action Decision Phase –Impact Computation(1)– • C1:Chunknotretainedbyanyneighbornodes • Num.ofneighbornodesthatwantchunks: 19 Impact for chunk s: Demand low High Impact high Low 3 1 3 1 3 1 Avoid redundant download Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  20. 20. Action Decision Phase –Impact Computation(2)– • C2: Chunk which some nodes retain,and some of neighbor nodes want the chunk • Num of neighbor nodes broadcasting chunk s: 20 Impact for s: Number of retaining nodes small large Impact high low 2 1 2 1 Avoid redundant broadcast Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  21. 21. Action Decision Phase –Roulette Selection– • RouletteSelection – Preparetworoulettesfor cellularandWiFi – Decideportionofeachchunkinproportiontoimpact – Selectachunkbyrouletteselection – Probabilityofselectingachunkwithimpactwi 21 Impact low High Probability low High High impact chunk Low impact chunk Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  22. 22. Problem in Basic Algorithm • Initially, allnodes intensivelyuse cellularnetwork while neighboring informationis not known • As time elapses,cellularis not used (neighbornodeshavechunks) 22 Time 100 Time Not adaptive to remaining time for deadline Short increase cellular usage to meet the deadline Long reduce cellular usage so that nodes exchange chunks via WiFi Download Rate (%) Cellular Usage Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  23. 23. Adaptation Mechanism (Extended from PerCom09 WiP) • Consider target downloadyield at elapsedtime to deadline – Currentdownloadyieldishigherthanthis,donotusecellular – Currentdownloadyieldis lowerthanthis,usecellular 23 100 Elapsed Time deadline :target DL yield Not use cellular Use cellular Download Yield (%) Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  24. 24. Organization 1. Background 2. RelatedWork 3. Problem Formulation 4. Proposed Algorithm 5. Evaluationthrough Simulations 6. Conclusion 24Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  25. 25. Evaluation Experiments Preliminary Experiment – Measureperformance,changinghellomessageperiodhandcollision avoidancerateb – Purpose: obtaingoodvaluesforhandb Experiment1 – Measurecellularnetworkusageanddownloadtimeforvariousdeadlines – Purpose: showadaptabilityforvariousdeadlinelengths Experiment2 – Measurecellularnetworkusageanddownloadtime,changingnumber ofcontents – Purpose:showadaptabilityforvariousnumberofadcontents  Metric:cellularnetworkusageratio(cellularusage) 25 Extension from PerCom version Cellular usage (%) = amount actually downloaded via cellular amount when all nodes download all chunks via cellular Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  26. 26. Common Simulation Parameters • We developed our own simulatorfor simulations in 1ms granularity 26 Common simulation parameters Size of each video ad 1.5MB (divided to 1000 chunks) Size of each chunk 1.5KB (sent in a packet) Num of ads that each node requests 2 (selected by Zipf distribution) Mobility Random Way Point (4km/hour) Field size 500m×500m Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  27. 27. Network Model 27 Cellular network Rate/connection: 1.2Mbps Maximum connections: 64 WiFi (ad-hoc mode) Bandwidth/range: 1.7Mbps Radio range: 200m Fading model: Nakagami fading MAC: CSMA/CA 0 0.25 0.5 0.75 1 0 50 100 150 200 Distance[m] M. Killat, F. Schmidt-Eisenlohr, H. Hartenstein, C. Rössel, P. Vortish, S. Assenmacher and F. Busch: ”Enabling Efficient and Accurate Large-Scale Simulations of VANETs for Vehicular Traffic Management,” Proc. of VANET2007 Packet Reception Rate (%) Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  28. 28. Parameters for preliminary experiment • Adaptation mechanism is not used 28 Parameters Number of ad contents 4 Number of nodes 500 Deadlines 30 min from starting time Collision avoidance rate b 0.0005~0.005 (by 0.0005 step) Hello message period h 5s, 10s, 30s, 60s Mobility Fixed and RWP Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  29. 29. Preliminary Experimental Result (cellular usage) • Asbdecreases,cellularusageimprovesreducecollision • Ashdecreases,cellularusageimprovesreduceredundantDL • Whenh=5andb=0.0005,cellularusagewas7.3% 29 7.3% Cellular Usage (%) Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  30. 30. Preliminary Experimental Result (download time) • b between0.001and0.002smallerdownloadtime – β<0.001:lowWiFiusage – β>0.002:manycollisions 30 Download time(s) - Small h suppresses cellular usage and prolongs download time Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  31. 31. Experiment1: Adaptability to Deadline Lengths • Evaluateadaptabilityto variousdeadline lengths • Suppose cold start case – Allnodessimultaneouslystartacquiringvideoadsafter eachnodedecidestwoadcontentsandtheirdeadlines – Hot startcaseisexplainedlater 31 Parameters used in Experiment1 Number of ad contents 10 Number of nodes 500 Deadlines 15, 30, 60, 90 minutes from starting time (fixed) h, b 5s, 0.0015 Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  32. 32. Result of Experiment1 (DL Yield over Time) • Withoutdeadlineadaptationmechanism – DLyieldincreasesslowlyafter90%.Manynodesmissdeadlines • Withdeadlineadaptationmechanism – Downloadyieldincreasesasexpected.Allnodesmeettheirdeadlines 32 Time DL Yield (%) Without mechanism With mechanism (deadline=90min) 60min 30min 15min Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  33. 33. Result of Experiment1 (Cellular Usage over Time) • Withoutdeadlineadaptationmechanism – Usescellularnetworkintensivelyonlyininitialphase • Withdeadlineadaptationmechanism – Constantlyusescellularnetwork,butincreasesusageinfinishing phase • In end phase, it takes long time to receive blank chunks via WiFi 33 40.5% 16.9% 4.3% 1.1% Time Without mechanism 15min 30min 60min 90min Number of chunks downloaded via cellular Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  34. 34. Experimental Result with “Hot Start” Configuration • Mobilenodesjoinandleavethesystem • Newnodesstartsobtainingvideoadsjustafterjoining • Measuredfor267nodesappearingafter200minuteselapses – Cellularusagewasreducedfurtherthan“coldstart”case – Minimumcellularusagewasreducedtoabout0.3% 34 Deadlines Cellular Usage (%) Cold start Hot start Configuration Initially 500nodes Poisson arrivals of 15s 120min lifetime 10 ad contents Deadlines: 15, 30, 60 (random) Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  35. 35. Experiment2: Scalability for Number of Contents • In actualsituation, many video ads may exist – Investigateifourmethodadaptivelyworksfordifferent numberof adcontents 35 Parameters for Experiment2 Number of Ad Contents 10, 20, 30, 40 Mobile Terminals 500 Time to Deadline 60 minutes Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  36. 36. Result of Experiment2 • Whenincreasingnumberofadcontents – Smallernumberofterminalswantthesamead – Ourmethodadaptivelyregulatedcellularusage • All terminals completed downloading all required contents – Evenfor40contents,cellularusagereducedtoabout34.9% 36 34.9% Number of ad contents Time Cellular usage (%) # of chunks via cellular 40 contents 30 20 10 Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  37. 37. Conclusion • Cooperativedownloadmethodformobilephonesforcontext-aware videoaddissemination – DoesnotsuppresscellularnetworkbyusingWi-Finetwork • Evaluationresultssupposingtypicalurbanscenarios – Cellularnetworkusagewasreducedbyupto98.9% – Inhotstartscenario,theusagewasreducedfurther – Adaptivetovariouslengthsofdeadlinesandnumberofvideoad contents FutureWork – Experimentwithrealisticsituation(realtraces,realmaps,etc) – Incentiveformobileterminals – multi-hoppathsinadhocnetwork 37Video Ads Dissemination through WiFi-Cellular Hybrid Networks
  38. 38. Hanano, H., Murata, Y., Shibata, N., Yasumoto, K., and Ito, M.: Video Ads Dissemination through WiFi-Cellular Hybrid Networks, Proc. of the 7th IEEE Int'l. Conf. on Pervasive Computing and Communications (PerCom 2009), pp. 322-327. DOI:10.1109/PERCOM.2009.4912787 [ PDF ] Video Ads Dissemination through WiFi-Cellular Hybrid Networks 38

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