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Olabisi E. Falowo and H. Anthony Chan

Joint Call Admission Control and Adaptive Bandwidth Management Scheme to Enhance QoS in Heterogeneous Wireless Networks. Olabisi E. Falowo and H. Anthony Chan. Department of Electrical Engineering University of Cape Town. Presentation Overview. Introduction

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Olabisi E. Falowo and H. Anthony Chan

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  1. Joint Call Admission Control and Adaptive Bandwidth Management Scheme to Enhance QoS in Heterogeneous Wireless Networks Olabisi E. Falowo and H. Anthony Chan Department of Electrical Engineering University of Cape Town

  2. PresentationOverview • Introduction • Need for Joint Call Admission Control • Comparison of RAT selection methods • Proposed Scheme • System Model • Performance Evaluation

  3. Ensure QoS Ensure Efficient utilization Limited resources Admission Control • University- Students • Hospital- Patients • Hotel- Guests • Conference- Papers • Airline- Passengers • Communication network- Calls

  4. Call Admission Control A call admission control (CAC) algorithm decides whether or not a call be accepted into a resource-constrained network without violating the service commitment made to already admitted calls Generally, CAC algorithms are triggered by any of the following events: • New call arrival • Handoff call arrival • Bearer modification

  5. Call Admission Control • CAC has been extensively studied in homogeneous wireless networks • For heterogeneous wireless networks, not many approaches to joint call admission (JCAC) problem are available in the literature • This work combines JCAC and adaptive bandwidth management to enhance QoS and System utilization

  6. RAT 2 RAT J RAT 1 Which network? Need for JCAC Algorithm • Existing homogeneous CAC algorithms can only make call admission decisions • Problem of RAT selection does not occur in homogeneous networks

  7. Need for JCAC Algorithm • In heterogeneous wireless network, there is need to make RAT selection decision in addition to call admission decision Can the arriving call be admitted or not? Call admission decision JCAC Into which RAT should the call be admitted? RAT selection decision

  8. RAT 2 RAT J RAT 1 Need for JCAC JCAC in heterogeneous wireless network is necessary for the following reasons: • Efficient radio resource utilization - Increased revenue • Enhanced QoS provisioning – Improvedusers’ satisfaction • Overall service cost reduction • Overall network stability

  9. Existing JCAC Algorithms • Initial RAT selection Algorithms • Fuzzy logic JCAC algorithms • RAT-specific JCAC algorithms

  10. Call admission decision JCAC RAT selection decision RAT Selection Methods • Random selection • Network load • Call service class • Service cost

  11. Comparison of the 3 JCAC Algorithms • Three JCAC algorithms are analyzed, evaluated and compared • These algorithms are: • Load-based JCAC • Service-class-based JCAC • Random-selection-based JCAC

  12. Algorithm Description • Load-based JCAC algorithm selects the least loaded RAT for an incoming call • Service-class-based JCAC selects a RAT for the incoming call based on its service class • Random-selection-based JCAC randomly selects a RAT for an incoming call Blocked RAT 1 Admitted JCAC RAT 2 RAT J Dropped

  13. Comparison of Call Blocking Probabilities

  14. Comparison of Call Dropping Probabilities

  15. Conclusion • Load-based JCAC has the best QoS whereas random-selection based JCAC has the least QoS performance

  16. PresentationOverview • Introduction • Need for Joint Call Admission Control • Comparison of RAT selection methods • Proposed Scheme • System Model • Performance Evaluation

  17. Proposed Adaptive JCAC Scheme + = Adaptive Bandwidth Management Load-Based JCAC AJCAC scheme

  18. Adaptive bandwidth management Load-based JCAC Objectives of the AJCAC Scheme • Guarantee the QoS requirements of all accepted calls • Prioritize handoff calls over new calls • Improve system utilization • Enhance connection-level QoS • Enhance overall network stability +

  19. System Model • The heterogeneous network comprises J number of RATs • It supports K classes of calls • Each class-i call requires a value, bi,w, where bi,w belongs to the set Bi = {bi,w} for i =1, 2,…,K and w =1, 2, …,Wi • Wi is the number of different bandwidth values that a class-i call can be allocated • For example, B1={16, 32, 64} in Kbps b1,min = b1,1 =16, b1,2 = 32, b1,max = b1,3 = 64

  20. JRRM RAT 1 RAT 2 RAT 3 Class-1 calls Class-2 calls System Model An example of heterogeneous network A two-class three- RAT heterogeneous network

  21. Components of the Proposed AJCAC Scheme • Joint call admission controller • Bandwidth allocation Unit • Bandwidth adaptation Unit

  22. Arrival of class-i call (Handoff call) yes no New call? Sort RATj for all j  hiin increasing order of current load and set n=1 Sort RATj for all j  hiin increasing order of current load and set n=1 Select the nth RAT Select the nth RAT Admit class-i call in the nth RAT and allocate b i, req Admit class-i call in the nth RAT and allocate b i, req Blocked yes yes bi,req  xi j bi,req  yi j no no n++ n++ no no RAT 1 n> Ji n> Ji yes yes Admitted bi,req= bi, (req-1) bi,req= bi, (req-1) n=1 n=1 JCAC RAT 2 no no bi,req < bi, min bi,req < bi, min yes yes n=1 n=1 Select the nth RAT and apply BAA RAT J Select the nth RAT and apply BAA Admit class-i call into the nth RAT and allocate b i, min Admit class-i call into the nth RAT and allocate b i, min yes yes bi,min  xij bi,min  yij Dropped no no n++ n++ no no n> Ji n> Ji yes yes Reject class-i call Reject class-i call JCAC Controller

  23. Fixed or dynamic £ £ £ £ = " £ t t ... t t ... t B j + 0 , j 1 , j i , j ( i 1 ), j k , j j Bandwidth Allocation Unit Availablebandwidth B2=t22 t12 BN=t2N B1=t21 t1N t11 t02 t2N t01 RAT N Access networks RAT 1 RAT 2

  24. Bandwidth Adaptation Unit For non-adaptive class-i calls For adaptive class-i calls bi,min=bi,max bi,max= bi,Ni bi,r=1<r<Ni bi,min= bi,1

  25. State Space

  26. Performance Evaluation • New call blocking probability • Handoff call dropping probability • Average system utilization

  27. New Call Blocking Probability

  28. Handoff Call Dropping Probability

  29. Call Blocking/Dropping Probability

  30. Normalized Average System Utilization

  31. Conclusion • Weinvestigate three RAT selection algorithms for heterogeneous wireless networks: load-based, service-class-based and random-selection-based JCAC • Results show that load-based JCAC has the best connection-level QoS performance whereas random-selection-based JCAC has the least QoS performance

  32. Conclusion • Wepropose load-based JCAC and adaptive bandwidth management scheme for heterogeneous wireless networks • Results show that the proposed AJCAC scheme enhances connection-level QoS and overall system utilization • Future work includes optimization of the AJCAC scheme using linear programming technique

  33. THANK YOU

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