Context Awareness in Network Resource Management

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Context Awareness in Network Resource Management. Χρήστος Αναγνωστόπουλος C ommunications N etwork L aboratory P ervasive C omputing R esearch G roup Department Informatics and Telecommunications University of Athens - Greece [email protected] , [email protected] Θέματα:. - PowerPoint PPT Presentation

Transcript of Context Awareness in Network Resource Management

  • Context Awareness in Network Resource Management

    Communications Network LaboratoryPervasive Computing Research GroupDepartment Informatics and TelecommunicationsUniversity of Athens - Greece

    [email protected],[email protected]

  • : (Context)

    (Network Resources)

    (Context-Aware Resource Management)

  • Context

  • - ContextContext: he information that can be used to characterize the situation of an entity, where an entity can be a person, place, physical or computational objects [Rakotonirainy 2000]

    , , .

  • - ContextPrimary/Physical Context: Location, Identity, Time, Activity {where, when, what occurs}User Context: User requirements, profile, charging and security policies, Position, QoS {who}Device Context: H/S Characteristics, Location, Connectivity, OS/Application running, Manufacturer, Network Operator, Security policy, Owner {what can be used}Application Context: Data format, Display, Voice, Connectivity, State {what can be obtained}Network Context: Bandwidth, Storage, Protocols, Caches, Signaling

    context information is not complete

  • - ContextRelation between contexts: The location of a device, which belongs to a user, may be his/her locationA users activity depends on his/her location

    My PDA is located in Room 1, your laptop is located in Room 2, and Rooms 1 and 2 are rooms of the 1st floor, then, my PDA is next to your laptop

    In Room 22, the number of people is greater than 5 and a .ppt application is running and Chris location is this room, then, the activity in Room 22 is presentation and speech notes are downloaded to the PDA of each user located in this room, during that presentation. SocialApplicationUserActivityDevicePhysicalPhysical

  • Network Resourcesas Network Context

  • Network ResourcesBasic Resources (physical entities/measurable quantities):Bandwidth: The transferred capacity between nodes of the network. Also, Timeslots and FrequenciesPower: Overall Signal to Noise ratio (SNR)Storage:The computing power of the network elementImplicit Resources Cache: Replicating part of the information residing to a remote server in the local system or in systems geographically dispersed inside the networkProtocol: Efficient protocol implementation/configuration (e.g., TCP window size) (IP vs. mobile IP)Signaling: Specific protocols for: connecting wirelessly, handing over,[Signaling messages consume part of useful bandwidth]

  • Network ResourcesRUserperspectiveOperatorperspectivePeriods of InterruptionsDropping ProbabilityBlocking ProbabilityHigh UtilizationCapacity=#users served simultaneouslyStable QoS {Allocated bandwidth, BER, Delay}High AutonomyHealth SafetyLoad Balancingpowerprocessingsignalingcacheprotocolstorage

  • ContextAwareness

  • Setting up the SceneResource Management Improvement of network performanceResources are specific and can be reused

    Mobility No fixed point of connectionDynamical resource allocation within mobile networks

    Task: Find specific characteristic that may assist us in the networkresource managementLocationVelocityDirectionPattern

  • Location EstimationTracking and PositioningCell Of Origin (COO): The differentiation of each cellTime Of Arrival (TOA): The time window between sending and receiving signalAngle Of Arrival (AOA): Measures the angle of the received signal, at least two directional antennas Signal Strength Measurement (SSM): By the signal attenuation equation

  • Categorization of Positioning SystemsInfrastructureInformation

  • Location PredictionKnowledge of the future location enables the network to avert undesirable situations (e.g., dropping a call/unavailability of resources)Required knowledge: Velocity and DirectionHistory of Movements/Handover behaviorTime in the cell of residenceHandoff estimation / predictive-adaptive bandwidth reservation e.g., Bhattacharya and Das (1999) Theory of Entropy (LeZi)Maguire and Liu (1996) Regularity-pattern detection (Kalman Filters)Hadjiefthymiades and Merakos (1999) Learning Automaton (Reward/Penalty)?

  • Location-Aware Resource ManagementExploitation of the terminal instantaneous position information toward the management of network resources (Synchronous Management)Continuous recording of terminal position + historical movements patterns + velocity/acceleration/direction implies proactive management of network resources (Asynchronous Management)timesynchronousSnapshotSort Term ManagementtimeasynchronousSnapshotLong Term Managementrecordingproactive

  • Short Term Resource Management (SRM)Admission Control: Context = {Users position, Idle/Active sessions, Roaming in the current cell}Event = {User on the boundary of two or more cells}Action= {Refuse the call initiation. This can be handled by an adjacent base station}

  • Short Term Resource Management (SRM)Network Reconfiguration: Context = {Users position, Idle/Active sessions, Roaming in a cluster of cells}Enhanced Context = {Calculation of the load in each cell, e.g., session initiation/termination probabilities}Event = {Some cells are congested}Action= {Re-organization/reconfiguration of resources. (i) Frequencies are temporarily borrowed by adjacent cells to cater for increased load(ii) Inside a cell with low user density, common channels (e.g., RACH-GSM), is reconfigured to use less timeslots per time unit(iii) Rearrangement of user population in order to optimally distribute the load and maximize utilizationThe user is provided with specific proposals on how to reach other cells where traffic load is less and better QoS can be attained}Case Study: MITOS (Alyfantis, Hadjiefthymiades, Merakos 2005)

  • Short Term Resource Management (SRM)Handover: Context = {Users position, Idle/Active sessions, Roaming in the current cells}Event = {User on the boundary of the cell, The load in the adjacent cell is lighter}Action= {(i)The terminal is instructed to switch communication i.e., perform a forced handover to the indicated base station.(ii) Forced handover could be the support of specific QoS requirements of the user (user profile, policy,terminal capability).No physical relocation is required}

  • Long Term Resource Management (LRM)Fine-grained pre-reservation of resources: Goal={Overcoming HO-induced problems. The user does not experience service discontinuations or low service quality. Reduction of HO blocking probability}Context = {User in the current cell}Action= {Find the most likely neighbor cell(s) of the current cell and reserve resources in those cells}Result={(i) Too early reservation leads to undesired waste of resources and low network utilization.(ii) Delayed pre-reservation may en-up with few resources than required, forcing the termination of sessions and low experienced QoS}More advancedWireless Resource ManagementNo advance reservation in candidate cells[No HO provision]Less advancedAdvance reservation in all cells[Crude HO provision]Advance reservation in most likely cells[Direction Sensitive HO provision]

  • Long Term Resource Management (LRM)Protocol Management: Context = {Different networks (GSM/WLAN), where the user can have access, User position, Spatial information about the network resources, like protocol stack/components/modules (4G infrastructures), Dual protocol stacks is not feasible}Event = {Switch from one network to other (TCP variant GSM to plain-vanilla TCP/WLAN)}Action= {(i) Advance protocol reconfiguration (downloading) to cater for another network, Push components, which will be requested by the terminal, to its nearest nodes/access points/base stations(ii) Tune protocol parameters w.r.t. current location and network status }Case Study: Museum Wearable(Sparacino 2002)

  • More contextLocationUser profile {Charging options, Preferences, Personalized services}Device profile {Capabilities}Service profile {LBS, software}

    From Mobile Computing toContext-Aware Computing toUbiquitous and Pervasive Computing

    http://p-comp.di.uoa.gr