DARP: Distance-Aware Relay Placement in WiMAX Mesh Networks

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DARP: Distance-Aware Relay Placement in WiMAX Mesh Networks. Weiyi Zhang * , Shi Bai * , Guoliang Xue § , Jian Tang † , Chonggang Wang ‡ * Department of Computer Science, North Dakota State University, Fargo § Department of Computer Science and Engineering, Arizona State University, Tempe - PowerPoint PPT Presentation

Text of DARP: Distance-Aware Relay Placement in WiMAX Mesh Networks

  • DARP: Distance-Aware Relay Placement in WiMAX Mesh NetworksWeiyi Zhang*, Shi Bai*, Guoliang Xue, Jian Tang, Chonggang Wang

    * Department of Computer Science, North Dakota State University, Fargo Department of Computer Science and Engineering, Arizona State University, Tempe Department of Electrical Engineering and Computer Science, Syracuse University, Syracuse NEC Laboratories America, Princeton, USA


  • OutlineIntroductionMotivation & ProblemObservation & GoalsSystem ModelSolution for DARP: Distance-Aware Relay station PlacementLORC-MIS // lower tierLORC-HS // lower tierMUST // upper tierSimulationConclusion

  • IntroductionThe emerging WiMAX technology is the 4G standard forhigh-speed (up to 75Mbps)long-range communications


  • IntroductionIEEE 802.16j enhances IEEE 802.16e by the concept of mesh networksBase Station (BS)Relay Station (RS)Subscriber Station (SS)BSRSSSRSSSSS

  • WiMAX 802.16j Relay Stationeliminate coverage holeRange extensionIntroductionInternetCoverageExtensionCoverage HoleMobile AccessBuildingPenetrationSSRSBSRSRSRSSS

  • n Subscriber Stations (SS)different user data rate requests

    Problem:finding where to place a minimum number of relay nodesto satisfy the certain performance requestsMotivationSSBSSSSSSSSS

  • Observation distance awareSignal to noise ratio (SNR) at receiverSNRr = Pr / N0Pr : power level at the receiverN0 : noise power is normally a constantSSuser data rate requests: 35 Mbps

  • Observation distance awareTwo-ray ground path loss modelPr = Pt Gt Gr Ht2 Hr2 d -

    Pt : Transmission power (constant)Gt / Gr : gains of transmitter/receiver antenna (constant)Ht /Hr : heights of transmitter/receiver antenna (constant)d : Euclidean distance between transmitter and receiver : attenuation factor (constant : 2~4)

    SSSShigher data rate requestlower data rate request

  • GoalsGiven a WiMAX mesh networkOne BSA set of SSs, S = {s1, s2, , Sn}A set of distance requirements for the SSs, D = {d1, d2, , dn}


  • GoalsSolve the distance-aware relay placement (DARP) problem by a minimum number of RSsProviding feasible coverage for each SScovered by at least one RS or BSEach placed RS has enough data rate to relay traffic for each SS or another RSSSSSBS25 Mbps 25 Mbps

  • System ModelA WiMAX mesh networkn SSs, S = {s1, s2, , Sn}Distance requirements D = {d1, d2, , dn}No routing and traffic relay capabilities

    BS, is aware of the location and distance requirement of each SS


  • Solution for DARP problemTwo-tiered relay modellower tierupper tierLORC-MISLORC-HSMUST

  • LORC-MISLORC-MISLOwer-tier Relay Coverage Maximal Independent Set based approximation solutionlower tier

  • LORC-MISFirst consider the SS with the smallest distance requirementHighest user data rate requirement12345C4C5C3C1C2d2d1d3d4d5

  • LORC-MISConstruct a regular hexagon with 7 possible positionsS2d2

  • LORC-MISChoose the point which covers most SSsS2S5S1S4S3

  • LORC-HSLOwer-tier Relay Coverage Hitting Set based approximation solutionLORC-HSlower tier

  • LORC-HSFind the Minimum hitting setto cover all SSs // {p0, p2}admits PTAS [18]s2s1s3s0S0={p0, p1}S1={p0, p1 , p2 , p3 , p4 , p5 , p7}S2={p2, p3 , p4 , p5 , p6}S3={p2, p4 , p5 , p6 , p7}[18] N. Mustafa and S. Ray, PTAS for geometric hitting set problems via local search, SCG09, pp. 17-22.

  • MUSTMinimum Upper-tier Steiner Treeupper tier

  • MUSTThe MUST ensures data rate for each individual SS or RSRS3RS1RS2BSABC151515161818

  • MUSTConstruct a complete graphAssign edge weight wNumber of RSsRS1RS2BSd1=10w=3d2=5102021165w=4w=3

  • MUSTMinimum spanning tree


  • MUSTPlace RSs on edgesRS1RS2BSd1=5w=3d2=52016w=354555444

  • Simulation SetupSSs are uniformly distributed in a square playing ground2000200030003000Distance requirements randomly distributed in [100,150]BS is deployed at the center of the fieldAll figures illustrate the average of 10 test runs for various scenarios

  • Simulation

  • Simulation lower-tier relay coverage

  • Simulation upper-tier relay connectivity

  • Simulation

  • Simulation

  • ConclusionThis paper studies the Distance-Aware Relay Placement (DARP) problemMulti-hop relay placementRelay coverageRelay connectivityTheENDThanks for your attention !

    **********************ILP: Gurobi Optimizer [9][9] Gurobi Optimization, http://www.gurobi.com/*