EIS SEMINAR SERIES2012 Glenford Mapp Principal Lecturer, Middlesex University

EIS SEMINAR SERIES2012  Motivation for the work  Handover Classification  Proactive-Handover  Mathematical Framework  Scenario  Location information  Wireless Footprinting  Implications for future networking infrastructure  Future Plans

EIS SEMINAR SERIES2012  The Internet will evolve in a physical sense  Core of the network ◦ Super-fast backbone (optical switching, etc) ◦ Fast access networks (MPLS, ATM)  Peripheral Wireless Networks ◦ Errors due to fading, etc; not just congestion ◦ Handover  Consequences  Degradation of end-to-end arguments

EIS SEMINAR SERIES2012 BACKBONE ACCESS NETWORKS WIRELESS NETWORKS

EIS SEMINAR SERIES2012  Devices will have more than one wireless interface.  Vertical handover – switching between different network interfaces to provide seamless connectivity  Vertical handover is good but it introduces a lot of QoS issues because the different wireless networks have different qualities of service

EIS SEMINAR SERIES2012  Affects your connections ◦ Some protocols react badly with respect to handover.  Affects your applications ◦ Need to think through how Quality-of-Service affects applications  Encapsulate these ideas in a Framework

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EIS SEMINAR SERIES2012  New framework ◦ We need to control network interfaces generically ◦ Make mobility support explicit  Vertical handover can have tsunami effects ◦ Merge network and transport services ◦ Make QoS support explicit  Provide a way for applications to negotiate with the network ◦ Security  Goal: Integration of Communication, Mobility, Quality-of-Service and Security

EIS SEMINAR SERIES2012 HARDWARE PLATFORM (MOBILE NODE) HARDWARE PLATFORM (BASE STATION) NETWORK ABSTRACTION (MOBILE NODE) NETWORK ABSTRACTION (BASE STATION) VERTICAL HANDOVER POLICY MANAGEMENT END SYSTEM TRANSPORT QOS LAYER APPLICATION ENVIRONMENTS CONFIGURATION LAYER NETWORK MANAGEMENT CORE TRANSPORT NETWORK QOS LAYER SERVICE PLATFORM CORE NETWORK PERIPHERAL NETWORK SAS NTS NAS QBS SECURITY LAYERS

EIS SEMINAR SERIES2012  Can’t explain everything about Y-Comm  It’s too big  Several people at Middlesex work on it: ◦ Mahdi Aiash : Security ◦ Fragkiskos Sardis: Mobile environments  Also Cambridge, Loughborough and USP  Concentrate on the Handover ◦ Ferdinand Katsriku & MSc students  See Y-Comm Research Webpage:  are/ycomm_research.aspx are/ycomm_research.aspx

EIS SEMINAR SERIES2012  Hard vs Soft Handovers ◦ Hard: - break before make ◦ Soft – make before break  Network vs Client Handovers ◦ Network – network in control (current) ◦ Client – future (Apple’s patent)  Upward vs Downward ◦ Upward – smaller to bigger coverage ◦ Downward – bigger to smaller

EIS SEMINAR SERIES2012 HANDOVER IMPERATIVE ALTERNATIVE REACTIVE PROACTIVE KNOWLEDGE-BASED MODEL-BASED NETPREF USERPREF CONTEXT SERVICES UNANTICIPATEDANTICIPATED

EIS SEMINAR SERIES2012 HANDOVER EXECUTION LAYER INPUT/OUTPUT LAYER POLICY LAYER (PONDER) WLANGPRS LAN L2 Triggers HIGHER LAYERS Interface Information

EIS SEMINAR SERIES2012  Proactive Policy Management ◦ The mobile node can know or estimate the network state at a given point before it arrives at that point ◦ Proactive Policies allow us to maximize the use of available channels provided you know the amount of time a channel will be available. ◦ That time is known as:  Time before vertical handover (TBVH)  Can significantly reduce packet loss during all vertical handovers

EIS SEMINAR SERIES2012  Proactive policies can themselves be divided into 2 types  Proactive knowledge-based systems ◦ Knowledge of which local wireless networks are operating at a given location and their strengths at that point ◦ We also need a system to maintain the integrity, accessibility and security of that data

EIS SEMINAR SERIES2012  Knowledge-based approach  Gather a database of the field strengths for each network around Cambridge  Need to maintain the database and also know how the results might be affected by seasonal effects

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EIS SEMINAR SERIES2012  Using a simple mathematical model  Define a radius at which handover should occur  Find out how much time I have before I hit that circle, given my velocity and direction  Calculate TBVH  Used simulation (OPNET)  Can be used in the real world as well as in simulation

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EIS SEMINAR SERIES2012  Introduction of additional functionality to Base Station at network boundary (BBS).  Distance between MS and BBS derived from location co-ordinates or  Estimated TBVH Movement of MS under BBS coverage (upward vertical handoff)

EIS SEMINAR SERIES2012 TBVH simulation in OPNET Modeler:

EIS SEMINAR SERIES2012  Extends Fatema’s work which only looked at upward handover  Looks at providing a complete mathematical framework  Uses the Law of Cosines  Needs accurate location information plus handover radius

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EIS SEMINAR SERIES2012 NET A NET B NET A NET B NET A NET B Complete Coverage Two Networks IntersectNetworks are Separate

EIS SEMINAR SERIES2012 Fatema Shaikh’s work

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EIS SEMINAR SERIES2012 CF from upward handover CE, EG, GH from downward handover EF = CF – CE = Intersection Distance Maximum Coverage PQ = AQ – AP PQ = R1 – (AB – R2) PQ = R1 + R2 - AB

EIS SEMINAR SERIES2012 A B R1 R2 For Separate Networks AB > R1 + R2 (Hard Handover)

EIS SEMINAR SERIES2012 A B C S T NET A NET B NET C Scenario Three WLANs in a single UMTS cell

EIS SEMINAR SERIES2012 A H1 C1 C2 B Y1 Z1 E1 Y2 Z2 C Y3 Z3 H3 E2 E3 S T H2 Analysis

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EIS SEMINAR SERIES2012  If the mobile node knows: ◦ Its location, direction and velocity  Via GPS, accelerometers ◦ The location of networking infrastructure  Type of radio network, position of the Access Points ◦ A good estimation of the Handover Radius  Hard to do  Then we can calculate the optimal time to handover over a large area using this mathematical framework

EIS SEMINAR SERIES2012  Mobile Operators ◦ Location of Base-Stations tends to be difficult to obtain.  Commercially sensitive  Location of WLANs ◦ Ad-hoc arrangements ◦ Almost impossible; need to do wardriving  Growing need to address this issue  IEEE :Media Independent Information Service (MIIS)  Cognitive Radio is also going to change this

EIS SEMINAR SERIES2012  Need 4 things ◦ Location of the Transmitter ◦ The power at the transmitter ◦ Propagation model ◦ The signal threshold at which handover should occur  Depends on the wireless receiver in the Mobile Node  More expensive the better  Most WLAN receivers can do dB  Mobile phones: around -120 dB

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EIS SEMINAR SERIES2012  Need better propagation models  Propagation Models ◦ Semi-static Models:  Free Space, Okumura and Hata Models  Less dependent on specific conditions ◦ Finite-element propagation models  Arshad and Katsriku  They take into account surroundings and specific conditions  Need for a more dynamic approach ◦ More context and location awareness

EIS SEMINAR SERIES2012  Let mobile nodes store information about their location, the signal strengths and other measurements in the core network  Make information on previous journeys available  Also this information to be shared with other mobile uses ◦ Need to make sure that we don’t forget privacy  Developed at USP

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EIS SEMINAR SERIES2012  System has been built and can be used. So we put the software on mobile phones and it uses the WF Server  This will allow us to look at building a better propagation model that is more tuned to location and context of mobile nodes  More dynamic; based on continuous measurements

EIS SEMINAR SERIES2012  Explore the effect of TBVH and NDT on channel allocation strategies  Could be the real game-changer for mobile operators  A mobile node is able to say much more when requesting a channel ◦ Will also know TBVH and NDT ◦ Allow better channel allocation

EIS SEMINAR SERIES2012 POLICY MANAGEMENT LAYER DECISION HANDOVER (BASE-STATION, 3G, QOS, TBVH, NDT) GPS Location, Speed, direction Connections (QoS) VERTICAL HANDOVER LAYER ACQUIRE RESOURCES ( 3G Base-station, QOS, TBVH, NDT) NETWORK MANAGEMENT LAYER Send to Mobile TOPOLOGY, RESOURCES, QoS NDT TBVH New QoS New IP CONFIGURABLE LAYER ACQUIRE CHANNEL (3G Base-station, QOS, TBVH, NDT) NETWORK ABSTRACTION LAYER BASE-STATION CHANNEL ACQUIRED DO IT NETWORK ABSTRACTION LAYER DATA CHANNNEL = 3G 3G=ACTIVE WLAN=PASSIVE WiMAX= PASSIVE 3GWLANWiMax 3GWLANWiMax Done DO IT L2 events Media Info CORE NETWORK Polling

EIS SEMINAR SERIES2012 WIRELESS NETWORK REQ (Time, TBVH, NDT) A A B B

EIS SEMINAR SERIES2012  MN A needs channel at (Time + TBVH) A  MN A releases channel at (Time + TBVH + NDT) A  MN B needs channel at (Time + TBVH) B  MN B releases channel at (Time + TBVH + NDT) B

EIS SEMINAR SERIES2012  No Contention ◦ (Time + TBVH) A < (Time + TBVH) B ◦ (Time + TBVH + NDT) A < (Time + TBVH) B  Contention: Two Types: Partial and Total ◦ (Time + TBVH) A < (Time + TBVH) B ◦ (Time + TBVH + NDT) A > (Time + TBVH) B ◦ Partial Contention  (Time + TBVH + NDT) A < (Time + TBVH + NDT) B ◦ Total Contention  (Time + TBVH + NDT) A >= (Time + TBVH + NDT) B

EIS SEMINAR SERIES2012  Request Granted as requested ◦ Channel granted at (Time + TVBH) A ◦ Channel released at (Time + TBVH + NDT) A  Request Granted but modified (for B) ◦ Channel granted at (Time + TBVH + NDT) A ◦ Channel released at (Time + TBVH + NDT) B  Request not granted ◦ Force handover to other network(s) ◦ MN node no longer stuck in queue  Much better use of core resources

EIS SEMINAR SERIES2012  Basic mathematical framework ◦ Develop a program for mobile phones  Better propagation models ◦ Use Wireless Footprinting  Investigate the implications for the core infrastructure ◦ New multi-channel allocation scheme based on TBVH and NDT ◦ Quantify improvement  Show mobile operators how they can provide much better services in this new context