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Distributed Resource Allocation in OFDMA-Based Relay Networks

Distributed Resource Allocation in OFDMA-Based Relay Networks. Christian Müller. Outline. Motivation Relay Networks Scenarios and Problems Definitions Distributed Resource Allocation Summary. 1. Outline. Motivation Relay Networks Scenarios and Problems Definitions

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Distributed Resource Allocation in OFDMA-Based Relay Networks

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  1. Distributed Resource Allocation in OFDMA-Based Relay Networks Christian Müller 12. Feb.2010 | Christian Müller

  2. Outline • Motivation Relay Networks • Scenarios and Problems Definitions • Distributed Resource Allocation • Summary 1 12. Feb. 2010 | Christian Müller

  3. Outline • Motivation Relay Networks • Scenarios and Problems Definitions • Distributed Resource Allocation • Summary 1 12. Feb. 2010 | Christian Müller

  4. Coverage in Today‘s Cellular Networks Coverage Problem Base Station (BS) wired backbone User Equipment (UE) 2 12. Feb. 2010 | Christian Müller

  5. Coverage in Relay Networks Coverage Problem Improved Receive Power Relay Station (RS) BS Base Station (BS) wired backbone wired backbone UE User Equipment (UE) 2 12. Feb. 2010 | Christian Müller

  6. Capacity in Today‘s Cellular Networks Capacity Problem wired backbone 3 12. Feb. 2010 | Christian Müller

  7. Capacity in Relay Networks Frequency Reuse Capacity Problem wired backbone wired backbone 3 12. Feb. 2010 | Christian Müller

  8. Outline • Motivation Relay Networks • Scenarios and Problems Definitions • Distributed Resource Allocation • Summary 4 12. Feb. 2010 | Christian Müller

  9. Considered Scenarios with Respect to Coverage and Capacity Problem Orthogonal Medium Access downlink transmission 1st 3rd • RS • operating in half-duplex mode • decode, re-encode & forward 2nd 5 12. Feb. 2010 | Christian Müller

  10. Considered Scenarios with Respect to Coverage and Capacity Problem Reuse Medium Access downlink transmission Orthogonal Medium Access downlink transmission 1st 1st 3rd 2nd • RS • operating in half-duplex mode • decode, re-encode & forward 2nd 2nd 5 12. Feb. 2010 | Christian Müller

  11. BS & RSs: time division OFDMA (Orthogonal Frequency Division Multiple Access) set of predefined beams power modulation and coding schemes 0 -10 -20 -30 antenna gain in dB -40 -50 -60 -150 -50 -100 0 100 150 50 direction in degrees Resource Units frequency time-frequency unit time slot grid of beams resource block 6 12. Feb. 2010 | Christian Müller

  12. Resource Allocation Problem user rates depend on allocation of all resource units • scenario • objective • Huge Resource Allocation Problem • solution based on channel quality information • duration for solution limited by coherence time 7 12. Feb. 2010 | Christian Müller

  13. Outline • Motivation Relay Networks • Scenarios and Problems Definitions • Distributed Resource Allocation • Summary 8 12. Feb. 2010 | Christian Müller

  14. Novel Concepts Orthogonal Medium Access Scenario Reuse Medium Access 9 12. Feb. 2010 | Christian Müller

  15. Novel Concepts Orthogonal Medium Access Distributed Concept for Orthogonal Medium Access Scenario Reuse Medium Access Distributed Concept for Reuse Medium Access 9 12. Feb. 2010 | Christian Müller

  16. Novel Concepts Trade-off performancevs. fairness maximize sum of user rates subject to minimum user rate maximize minimum user rate Orthogonal Medium Access Distributed Concept for Orthogonal Medium Access Scenario Reuse Medium Access Distributed Concept for Reuse Medium Access 9 12. Feb. 2010 | Christian Müller

  17. Novel Concepts Trade-off performancevs. fairness maximize sum of user rates subject to minimum user rate maximize minimum user rate Orthogonal Medium Access cf. thesis cf. thesis Scenario cf. thesis exemplarily presented Reuse Medium Access 9 12. Feb. 2010 | Christian Müller

  18. Distributed Concept for Reuse Medium Access Assumptions Flow of Subproblems BS: design of grids of beams beams applied on time-frequency unit RS: allocation of resource blocks • uniformly allocated power • fixed number of allocated • slots bits per slot on RS-to-UE links BS: allocation of resource blocks 10 12. Feb. 2010 | Christian Müller

  19. Distributed Concept for Reuse Medium Access Assumptions Flow of Subproblems BS: design of grids of beams beams applied on time-frequency unit RS: allocation of resource blocks • uniformly allocated power • fixed number of allocated • slots bits per slot on RS-to-UE links BS: allocation of resource blocks 10 12. Feb. 2010 | Christian Müller

  20. Design of Grids of Beams unknown: – current positions of UEs – channel quality information inter-beam interference co-channel interference 11 12. Feb. 2010 | Christian Müller

  21. Design of Grids of Beams unknown: – current positions of UEs – channel quality information • non-adaptive solution: • each beam equally frequent • equal distance • randomly allocated to time- • frequency unit 11 12. Feb. 2010 | Christian Müller

  22. Design of Grids of Beams unknown: – current positions of UEs – channel quality information inter-beam interference • non-adaptive solution: • each beam equally frequent • equal distance • randomly allocated to time- • frequency unit known: + positions of BS and RSs + pathloss model + beams + user distribution RS2 RS1 co-channel interference 11 12. Feb. 2010 | Christian Müller

  23. Adaptive Design • metric for each combination of beams: • determine interference based on pathloss model and antenna gain • average value based on coverage area and user distribution coverage area of beam 12 12. Feb. 2010 | Christian Müller

  24. Adaptive Design • metric for each combination of beams: • determine interference based on pathloss model and antenna gain • average value based on coverage area and user distribution coverage area of beam use beams more often where receiving stations are expected hot spot 12 12. Feb. 2010 | Christian Müller

  25. Adaptive Design • metric for each combination of beams: • determine interference based on pathloss model and antenna gain • average value based on coverage area and user distribution coverage area of beam use beams more often where receiving stations are expected hot spot allocate beams to time-frequency units sequentially → best fit algorithm 12 12. Feb. 2010 | Christian Müller

  26. Distributed Concept for Reuse Medium Access Assumptions Flow of Subproblems BS: design of grids of beams beams applied on time-frequency unit RS: allocation of resource blocks • uniformly allocated power • fixed number of allocated • slots bits per slot on RS-to-UE links BS: allocation of resource blocks 13 12. Feb. 2010 | Christian Müller

  27. Motivation of Assumptions co-channel interference 14 12. Feb. 2010 | Christian Müller

  28. Motivation of Assumptions • Distributed Concept for Reuse Medium Access: • uniformly allocated power • fixed number of allocated • slots • design of grids of beams 14 12. Feb. 2010 | Christian Müller

  29. Motivation of Assumptions pilots of BS • Distributed Concept for Reuse Medium Access: • uniformly allocated power • fixed number of allocated • slots • design of grids of beams • pilot phase → Signal-to-Interference-plus-Noise Ratio (SINR) estimation 14 12. Feb. 2010 | Christian Müller

  30. Motivation of Assumptions • Distributed Concept for Reuse Medium Access: • uniformly allocated power • fixed number of allocated • slots • design of grids of beams pilots of RS pilots of RS • pilot phase → SINR estimation 14 12. Feb. 2010 | Christian Müller

  31. Motivation of Assumptions • Distributed Concept for Reuse Medium Access: • uniformly allocated power • fixed number of allocated • slots • design of grids of beams • pilot phase → SINR estimation • SINR feedback 14 12. Feb. 2010 | Christian Müller

  32. Motivation of Assumptions • Distributed Concept for Reuse Medium Access: • uniformly allocated power • fixed number of allocated • slots • design of grids of beams • pilot phase → SINR estimation • SINR feedback 14 12. Feb. 2010 | Christian Müller

  33. Motivation of Assumptions SINR knowledge BS • Distributed Concept for Reuse Medium Access: • uniformly allocated power • fixed number of allocated • slots • design of grids of beams • pilot phase → SINR estimation • SINR feedback • allocation of resource blocks SINR knowledge RS2 SINR knowledge RS1 14 12. Feb. 2010 | Christian Müller

  34. Motivation of Assumptions • Distributed Concept for Reuse Medium Access: • uniformly allocated power • fixed number of allocated • slots • design of grids of beams • pilot phase → SINR estimation • SINR feedback • allocation of resource blocks • data transmission 14 12. Feb. 2010 | Christian Müller

  35. Distributed Concept for Reuse Medium Access Assumptions Flow of Subproblems BS: design of grids of beams beams applied on time-frequency unit RS: allocation of resource blocks • uniformly allocated power • fixed number of allocated • slots bits per slot on RS-to-UE links BS: allocation of resource blocks 15 12. Feb. 2010 | Christian Müller

  36. Allocation of Resource Blocks SINR values of resource blocks → bits per resource blocks • Literature: • one problem across all links • requires knowledge of SINR values in one point for • all resource blocks • all links use SINR values locally → distributed allocation 16 12. Feb. 2010 | Christian Müller

  37. frequency frequency time time Allocation of Resource Blocks Provided by RS • allocate resource blocks with objective max. min. user rate • non-adaptive • adaptive example with 2 beams: UE3 UE3 1st beam: UE1 UE1 UE2 UE1 UE1 UE1 UE3 UE2 2nd beam: UE2 UE2 UE3 17 12. Feb. 2010 | Christian Müller

  38. Allocation of Resource Blocks Provided by RS • allocate resource blocks with objective max. min. user rate • non-adaptive • adaptive • RSs know bits per slot for each RS-to-UE link 17 12. Feb. 2010 | Christian Müller

  39. Allocation of Resource Blocks Provided by RS • allocate resource blocks with objective max. min. user rate • non-adaptive • adaptive • RS knows bits per slot for each RS-to-UE link • feedback to BS 17 12. Feb. 2010 | Christian Müller

  40. Allocation of Resource Blocks Provided by BS • allocate resource blocks with objective max. min. weighted user rate • UE weighted by 1, RS weighted • by (number of UEs)-1 UE5 UE4 frequency UE4 UE5 1st beam: RS1 RS1 RS2 RS1 RS2 time frequency RS2 RS1 2nd beam: UE4 RS2 RS1 time 18 12. Feb. 2010 | Christian Müller

  41. Allocation of Resource Blocks Provided by BS • allocate resource blocks with objective max. min. weighted user rate • UE weighted by 1, RS weighted • by (number of UEs)-1 • RS is not allocated more than • required UE5 UE4 RS1 RS2 18 12. Feb. 2010 | Christian Müller

  42. 200 100 RS 0 Coordinates in meter BS -100 RS -200 -200 -100 0 100 200 300 Coordinates in meter Evaluation Parameters 19 12. Feb. 2010 | Christian Müller

  43. Performance Evaluation Design of Grids of Beams 120 GoB: design of grids of beams RB: allocation of resource blocks all-adapt. BS: GoB, RB | RS: RB non-adapt. 100 80 60 average minimum user rate in bits/slot 40 20 0 10 20 30 40 5 15 25 35 number of UEs 20 12. Feb. 2010 | Christian Müller

  44. all-adapt. BS: GoB, RB | RS: RB non-adapt. Performance Evaluation Allocation of Resource Blocks 120 GoB: design of grids of beams RB: allocation of resource blocks 100 80 60 average minimum user rate in bits/slot 40 20 0 10 20 30 40 5 15 25 35 number of UEs 21 12. Feb. 2010 | Christian Müller

  45. Signalling RS to BS 105 Reference Central genius approach Distributed Concept For Reuse Medium Access • all time-frequency units and best modulation and coding scheme used 104 103 • per resource block: - channel gain - phase - noise/interference • assumption: 4 bits per value number of bits/slot 102 101 100 3 4 5 6 7 8 9 10 2 1 number of UEs served by RS 22 12. Feb. 2010 | Christian Müller

  46. Outline • Motivation Relay Networks • Scenarios and Problems Definitions • Distributed Resource Allocation • Summary 23 12. Feb. 2010 | Christian Müller

  47. Summary • formulation of resource allocation problems in relay networks • aiming at fair user rate allocation & high sum rate allocation • in scenarios without & with co-channel interference • concepts dividing problem in subproblems • design grids of beams solved first in order to gain information about channels • adaptive design of grids of beams according to user distribution and pathloss • use information about channel locally and allocate resource blocks distributed across BS and RSs • low amount of signalling between RS and BS through bits/slot signalling 24 12. Feb. 2010 | Christian Müller

  48. Thank you. 12. Feb. 2010 | Christian Müller

  49. Novel Adaptive Solutions Maximize Sum of User Rates Subject to Minimum User Rate Maximize Minimum User Rate Design of Grids of Beams BS: Allocation of Resource Blocks BS: Allocation of Resource Blocks • noise • inter-beam • interference BS: Allocation of Power and Bits BS: Allocation of Power and Bits RS: Allocation of Resource Blocks RS: Allocation of Resource Blocks RS: Allocation of Power and Bits RS: Allocation of Power and Bits Allocation of Slots Allocation of Slots • noise • inter-beam • interference • co-channel • interference Design of Grids of Beams BS: Allocation of Resource Blocks BS: Allocation of Resource Blocks RS: Allocation of Resource Blocks RS: Allocation of Resource Blocks A 12. Feb. 2010 | Christian Müller

  50. Design of Grids of Beams Motivation of Concepts Current information about co-channel interference Pathloss model and user distribution Joint concept for conventional network Entire concept for relay networks Use channel knowledge locally and define distributed solution Central solution Allocation of Resource Blocks, Power and Bits Solution based on continuous number of bits depending on SINR Solutions for combinational problems Joint solution based on flexible number of slots for single UE Allocation of slots part of the concept for multiple RSs and UEs Allocation of Slots B 12. Feb. 2010 | Christian Müller

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