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12. Feb.2010 | Christian Müller Distributed Resource Allocation in OFDMA-Based Relay Networks Christian Müller
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12. Feb. 2010 | Christian Müller Outline Motivation Relay Networks Scenarios and Problems Definitions Distributed Resource Allocation Summary 1
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12. Feb. 2010 | Christian Müller Outline Motivation Relay Networks Scenarios and Problems Definitions Distributed Resource Allocation Summary 1
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12. Feb. 2010 | Christian Müller Coverage in Today‘s Cellular Networks Base Station (BS) User Equipment (UE) wired backbone Coverage Problem 2
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12. Feb. 2010 | Christian Müller Coverage in Relay Networks Base Station (BS) User Equipment (UE) wired backbone Coverage Problem BS UE wired backbone Improved Receive Power Relay Station (RS) 2
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12. Feb. 2010 | Christian Müller Capacity in Today‘s Cellular Networks wired backbone Capacity Problem 3
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12. Feb. 2010 | Christian Müller Capacity in Relay Networks wired backbone Capacity Problem Frequency Reuse wired backbone 3
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12. Feb. 2010 | Christian Müller Outline Motivation Relay Networks Scenarios and Problems Definitions Distributed Resource Allocation Summary 4
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12. Feb. 2010 | Christian Müller Considered Scenarios with Respect to Coverage and Capacity Problem 1st 2nd 3rd 5 RS operating in half-duplex mode decode, re-encode & forward Orthogonal Medium Access downlink transmission
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12. Feb. 2010 | Christian Müller Considered Scenarios with Respect to Coverage and Capacity Problem 1st 2nd 1st 2nd 3rd 5 Orthogonal Medium Access downlink transmission Reuse Medium Access downlink transmission RS operating in half-duplex mode decode, re-encode & forward
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12. Feb. 2010 | Christian Müller Resource Units BS & RSs: time division OFDMA (Orthogonal Frequency Division Multiple Access) set of predefined beams power modulation and coding schemes 6 time frequency slot time-frequency unit grid of beams -150 -100 -50 0 50 100150 0 -10 -30 -40 -50 -60 -20 direction in degrees antenna gain in dB resource block
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12. Feb. 2010 | Christian Müller Resource Allocation Problem 7 user rates depend on allocation of all resource units Huge Resource Allocation Problem solution based on channel quality information duration for solution limited by coherence time scenario objective
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12. Feb. 2010 | Christian Müller Outline Motivation Relay Networks Scenarios and Problems Definitions Distributed Resource Allocation Summary 8
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12. Feb. 2010 | Christian Müller Novel Concepts Scenario 9 Orthogonal Medium Access Reuse Medium Access
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12. Feb. 2010 | Christian Müller Novel Concepts Scenario Distributed Concept for Orthogonal Medium Access Distributed Concept for Reuse Medium Access 9 Orthogonal Medium Access Reuse Medium Access
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12. Feb. 2010 | Christian Müller Novel Concepts maximize sum of user rates subject to minimum user rate maximize minimum user rate Trade-off performance vs. fairness Scenario Distributed Concept for Orthogonal Medium Access Distributed Concept for Reuse Medium Access 9 Orthogonal Medium Access Reuse Medium Access
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12. Feb. 2010 | Christian Müller Novel Concepts exemplarily presentedcf. thesis 9 maximize sum of user rates subject to minimum user rate maximize minimum user rate Trade-off performance vs. fairness Scenario Orthogonal Medium Access Reuse Medium Access
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12. Feb. 2010 | Christian Müller Distributed Concept for Reuse Medium Access BS: design of grids of beams RS: allocation of resource blocks beams applied on time-frequency unit BS: allocation of resource blocks bits per slot on RS-to-UE links - uniformly allocated power - fixed number of allocated slots AssumptionsFlow of Subproblems 10
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12. Feb. 2010 | Christian Müller Distributed Concept for Reuse Medium Access BS: design of grids of beams RS: allocation of resource blocks beams applied on time-frequency unit BS: allocation of resource blocks bits per slot on RS-to-UE links - uniformly allocated power - fixed number of allocated slots AssumptionsFlow of Subproblems 10
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12. Feb. 2010 | Christian Müller Design of Grids of Beams 11 inter-beam interference co-channel interference unknown: – current positions of UEs – channel quality information
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12. Feb. 2010 | Christian Müller Design of Grids of Beams 11 unknown: – current positions of UEs – channel quality information non-adaptive solution: each beam equally frequent equal distance randomly allocated to time- frequency unit
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12. Feb. 2010 | Christian Müller Design of Grids of Beams 11 inter-beam interference co-channel interference RS 1 RS 2 unknown: – current positions of UEs – channel quality information 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
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12. Feb. 2010 | Christian Müller Adaptive Design 12 coverage area of beam metric for each combination of beams: determine interference based on pathloss model and antenna gain average value based on coverage area and user distribution
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12. Feb. 2010 | Christian Müller Adaptive Design 12 coverage area of beam metric for each combination of beams: determine interference based on pathloss model and antenna gain average value based on coverage area and user distribution use beams more often where receiving stations are expected hot spot
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12. Feb. 2010 | Christian Müller Adaptive Design 12 coverage area of beam metric for each combination of beams: determine interference based on pathloss model and antenna gain average value based on coverage area and user distribution use beams more often where receiving stations are expected allocate beams to time-frequency units sequentially → best fit algorithm hot spot
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12. Feb. 2010 | Christian Müller Distributed Concept for Reuse Medium Access BS: design of grids of beams RS: allocation of resource blocks beams applied on time-frequency unit BS: allocation of resource blocks bits per slot on RS-to-UE links - uniformly allocated power - fixed number of allocated slots AssumptionsFlow of Subproblems 13
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12. Feb. 2010 | Christian Müller Motivation of Assumptions 14 co-channel interference
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12. Feb. 2010 | Christian Müller Motivation of Assumptions Distributed Concept for Reuse Medium Access: uniformly allocated power fixed number of allocated slots design of grids of beams 14
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12. Feb. 2010 | Christian Müller 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 1.pilot phase → Signal-to- Interference-plus-Noise Ratio (SINR) estimation 14
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12. Feb. 2010 | Christian Müller Motivation of Assumptions pilots of RS Distributed Concept for Reuse Medium Access: uniformly allocated power fixed number of allocated slots design of grids of beams 1.pilot phase → SINR estimation 14
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12. Feb. 2010 | Christian Müller Motivation of Assumptions Distributed Concept for Reuse Medium Access: uniformly allocated power fixed number of allocated slots design of grids of beams 1.pilot phase → SINR estimation 2.SINR feedback 14
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12. Feb. 2010 | Christian Müller Motivation of Assumptions Distributed Concept for Reuse Medium Access: uniformly allocated power fixed number of allocated slots design of grids of beams 1.pilot phase → SINR estimation 2.SINR feedback 14
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12. Feb. 2010 | Christian Müller Motivation of Assumptions Distributed Concept for Reuse Medium Access: uniformly allocated power fixed number of allocated slots design of grids of beams 1.pilot phase → SINR estimation 2.SINR feedback 3.allocation of resource blocks SINR knowledge RS 1 SINR knowledge RS 2 SINR knowledge BS 14
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12. Feb. 2010 | Christian Müller Motivation of Assumptions Distributed Concept for Reuse Medium Access: uniformly allocated power fixed number of allocated slots design of grids of beams 1.pilot phase → SINR estimation 2.SINR feedback 3.allocation of resource blocks 4.data transmission 14
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12. Feb. 2010 | Christian Müller Distributed Concept for Reuse Medium Access BS: design of grids of beams RS: allocation of resource blocks beams applied on time-frequency unit BS: allocation of resource blocks bits per slot on RS-to-UE links - uniformly allocated power - fixed number of allocated slots AssumptionsFlow of Subproblems 15
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12. Feb. 2010 | Christian Müller Allocation of Resource Blocks 16 Literature: one problem across all links requires knowledge of SINR values in one point for -all resource blocks -all links SINR values of resource blocks → bits per resource blocks use SINR values locally → distributed allocation
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12. Feb. 2010 | Christian Müller Allocation of Resource Blocks Provided by RS 17 allocate resource blocks with objective max. min. user rate a)non-adaptive b)adaptive UE 2 UE 1 UE 3 time frequency time frequency 1st beam: 2nd beam: UE 1 UE 3 UE 2 example with 2 beams:
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12. Feb. 2010 | Christian Müller Allocation of Resource Blocks Provided by RS 17 allocate resource blocks with objective max. min. user rate a)non-adaptive b)adaptive RSs know bits per slot for each RS- to-UE link
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12. Feb. 2010 | Christian Müller Allocation of Resource Blocks Provided by RS 17 allocate resource blocks with objective max. min. user rate a)non-adaptive b)adaptive RS knows bits per slot for each RS- to-UE link feedback to BS
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12. Feb. 2010 | Christian Müller Allocation of Resource Blocks Provided by BS 18 UE 5 UE 4 RS 1 RS 2 2nd beam: time frequency 1st beam: RS 1 UE 4 UE 5 RS 2 time frequency UE 4 RS 2 RS 1 allocate resource blocks with objective max. min. weighted user rate UE weighted by 1, RS weighted by (number of UEs) -1
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12. Feb. 2010 | Christian Müller Allocation of Resource Blocks Provided by BS 18 UE 5 UE 4 RS 1 RS 2 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
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12. Feb. 2010 | Christian Müller Evaluation Parameters ParameterValue size grids of beams3 time-frequency units64 number of resource blocks192 number of slots100 bits per symbol of modulation and coding schemes 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8 main lobe direction0°, 30°, 60°, …, 330° channel model BS/RS to UEnon-line of sight model channel model BS to RSline of sight model Coordinates in meter BS RS 0 -100 -200 200 100 0-100 -200 300 100 200 19
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12. Feb. 2010 | Christian Müller 100 Performance Evaluation Design of Grids of Beams 20 all-adapt. BS: GoB, RB | RS: RB non-adapt. number of UEs 5 10 15 20 25 30 35 40 0 120 80 60 40 20 average minimum user rate in bits/slot GoB: design of grids of beams RB: allocation of resource blocks
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12. Feb. 2010 | Christian Müller Performance Evaluation Allocation of Resource Blocks 21 all-adapt. BS: GoB, RB | RS: RB non-adapt. number of UEs 5 0 10 15 20 25 30 35 40 120 100 80 60 40 20 average minimum user rate in bits/slot GoB: design of grids of beams RB: allocation of resource blocks
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12. Feb. 2010 | Christian Müller 1 10 1 10 3 Signalling RS to BS 22 per resource block: - channel gain - phase - noise/interference assumption: 4 bits per value all time-frequency units and best modulation and coding scheme used number of UEs served by RS 10 0 10 2 10 4 10 5 number of bits/slot 2 345678910 Reference Central genius approach Distributed Concept For Reuse Medium Access
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12. Feb. 2010 | Christian Müller Outline Motivation Relay Networks Scenarios and Problems Definitions Distributed Resource Allocation Summary 23
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12. Feb. 2010 | Christian Müller 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
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12. Feb. 2010 | Christian Müller Thank you.
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12. Feb. 2010 | Christian Müller Novel Adaptive Solutions Maximize Sum of User Rates Subject to Minimum User Rate Maximize Minimum User Rate noise inter-beam interference noise inter-beam interference co-channel interference Design of Grids of Beams Allocation of Slots BS: Allocation of Resource Blocks Allocation of Slots BS: Allocation of Resource Blocks BS: Allocation of Power and Bits RS: Allocation of Resource Blocks RS: Allocation of Power and Bits BS: Allocation of Resource Blocks RS: Allocation of Resource Blocks Design of Grids of Beams A
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12. Feb. 2010 | Christian Müller Motivation of Concepts Design of Grids of Beams Allocation of Resource Blocks, Power and Bits Allocation of Slots Solution based on continuous number of bits depending on SINR Joint solution based on flexible number of slots for single UE Central solution Joint concept for conventional network Current information about co-channel interference Solutions for combinational problems Allocation of slots part of the concept for multiple RSs and UEs Use channel knowledge locally and define distributed solution Entire concept for relay networks Pathloss model and user distribution B
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