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EDGE-PRIORITIZED CHANNEL- AND TRAFFIC-AWARE UPLINK CARRIER AGGREGATION IN LTE-ADVANCED SYSTEMS

EDGE-PRIORITIZED CHANNEL- AND TRAFFIC-AWARE UPLINK CARRIER AGGREGATION IN LTE-ADVANCED SYSTEMS. AUTHORS R. SIVARAJ, A. PANDE, K. ZENG, K. GOVINDAN, P. MOHAPATRA . PRESENTER R. SIVARAJ, Ph.D student in CS, UC DAVIS, CA, USA Email: rsivaraj AT ucdavis DOT edu

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EDGE-PRIORITIZED CHANNEL- AND TRAFFIC-AWARE UPLINK CARRIER AGGREGATION IN LTE-ADVANCED SYSTEMS

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  1. EDGE-PRIORITIZED CHANNEL- AND TRAFFIC-AWARE UPLINK CARRIER AGGREGATION IN LTE-ADVANCED SYSTEMS AUTHORS R. SIVARAJ, A. PANDE, K. ZENG, K. GOVINDAN, P. MOHAPATRA PRESENTER R. SIVARAJ, Ph.D student in CS, UC DAVIS, CA, USA Email: rsivaraj AT ucdavisDOT edu http://spirit.cs.ucdavis.edu

  2. AGENDA OF THE PRESENTATION • INTRODUCTION • ISSUES IN EXISTING LITERATURE • PROBLEM STATEMENT • KEY CONTRIBUTIONS • WHY UPLINK? • SYSTEM MODEL • CARRIER AGGREGATION • SCHEDULING • PERFORMANCE EVALUATION • DISCUSSION • CONCLUSION

  3. INTRODUCTION TO LONG TERM EVOLUTION 90 1.4 MHz CC 2600 MHz 5 MHz CC 2025 MHz 20 MHz CC 1900 MHz 15 MHz CC 1525 MHz 10 MHz CC 800 MHz

  4. INTRODUCTION TO LTE-ADVANCED • LTE RELEASE 10 (4G CELLULAR NETWORK – EVOLVED FROM OFDMA LTE) • PROVISIONING NEXT-GEN TELECOMMUNICATION SERVICES • PEAK DATA RATES: • DOWNLINK (Low Mobility): 1 Gbps • UPLINK (Low Mobility): 500 Mbps • DOWNLINK (High Mobility): 100 Mbps • PEAK BANDWIDTH: 100 MHz • AGGREGATION OF UPTO 5 COMPONENT CARRIERS • SCALABLE LTE BANDWIDTHS RANGING FROM 1.4 MHz to 20 MHz • PHYSICAL RESOURCE BLOCKS (PRB) • CONSTITUENT OF 12 SUB-CARRIERS (EACH 18 kHz) – MINIMUM RESOURCE ALLOCATION UNIT FOR ANY UE • DOWNLINK: CONTIGUOUS/DIS-CONTIGUOUS SUB-CARRIERS FOR A SINGLE PRB (CHANNEL) • UPLINK: CONTIGUOUS SUB-CARRIERS FOR A SINGLE PRB (RECOMMENDED)

  5. CARRIER AGGREGATION SESSION ADMISSION CONTROL L3 – CC ASSIGNMENT L2 – PACKET SCHEDULING L2 – PACKET SCHEDULING L2 – PACKET SCHEDULING LINK ADAPTATION LINK ADAPTATION LINK ADAPTATION HARQ HARQ HARQ MAC MAC MAC CC CC CC

  6. ISSUES IN EXISTING LITERATURE Am in here for a video conferencing Same number of resources for both ? Send an email to my boss applying for leave Now I wanna surf Facebook Video gaming with my friends for the next half-hour Ah !!!! Jus wanna surf Facebook Iwanna stream a HD video A VoIP call to my manager Center/Close to center UEs contribute to less UL traffic Edge UEs contribute to a bulkier data

  7. UE GROUPING • Grouping of UEs based on spatial correlation – Similar channel conditions and radio characteristics CQI CQI CQI CQI CQI CQI

  8. KEY CONTRIBUTIONS OF THE PAPER PROBLEM STATEMENT: How to optimally provision next-generation telecommunication services in LTE-Advanced uplink ? APPROACH: Prioritization of cell-edge UE groups for channel- and Traffic-aware Carrier Aggregation Effectively accommodates log-normal shadowing, channel fading and propagation losses which adversely impact edge throughput Efficient representation of under-represented weak terminals Profile-based Proportional Fair Packet Scheduling Resolves contention of resources using inter- and intra-group scheduling on a time-domain and frequency-domain basis

  9. MOTIVATION - WHY UPLINK ? • HIGHER UPLINK TRAFFIC WITH THE EVOLUTION OF WEB 2.0 • UPLINK COULD POSSIBLY EXCEED DOWNLINK IN 2020 (CISCO ESTIMATES) • MOBILE TERMINALS – MORE POWER-LIMITED THAN THE eNodeB • RADIO CHANNEL CHARACTERISTICS (LIKE PATH LOSS) INFLUENCE UE TRANSMISSION POWER • FREQUENCY DIVERSITY AND AMC : NOT EFFECTIVELY-UTILIZED IN THE UPLINK • MOTIVATION FOR SUBSCRIBERS TO CONTRIBUTE TO UPLINK TRAFFIC FROM THEIR HAND-HELD DEVICES

  10. MOTIVATION - WHY CHANNEL-AWARE AND EDGE ? • 41% INCREASE IN THROUGHPUT OVER CHANNEL-BLIND ASSIGNMENT • 57% INCREASE IN EDGE UE THROUGHPUT • PATH LOSS-BASED ASSIGNMENT FOR CHANNEL AWARENESS

  11. SYSTEM MODEL • NON-ADJACENT INTER-BAND CARRIER AGGREGATION (800 MHz, 1525 MHz, 1800 MHz, 2025 MHz, 2600 MHz) • FOR ANY UE, ASSIGNABLE CCSET CONTAINS CCs WHOSE PATH LOSS IS LESS THAN A PRE-DEFINED THRESHOLD • ASSIGN RESOURCES ONLY FROM ASSIGNABLE CCs TO UE GROUPS • UEs FROM EACH GROUP SEND QCI TO eNB (TRAFFIC SUBSCRIPTION) • DETERMINATION OF AMBR REQUIREMENTS FOR EACH GROUP • EQUAL POWER ALLOCATION ON ALL FREQUENCY BANDS WITH SINR, CQI AND SPECTRAL EFFICIENCY COMPUTATIONS: QCI CALCULATE AMBR QCI

  12. DISTRIBUTION OF ASSIGNABLECCsTO UEs CC1 UE1 UE2 CC2 CC3 UE3 N CC4 UE4 CC5 UE5

  13. CARRIER AGGREGATION – THE OBJECTIVE • AGGREGATING THE CCs AND ASSIGNING THEIR PRBs TO THE GROUPS • Theoretical Formulation: NP-Hard Generalized Assignment Problem: • SOLUTION : SUBSET OF ITEMS (AGGREGATED CARRIER U) TO BE ASSIGNEDTO THE BINS • FEASIBLE SOLUTION: SOLUTION WITH MAXIMUM PROFIT (ACHIEVED UPLINK THROUGHPUT) CC1 CC2 CCi … CCn ITEMS βij pij G1 G2 Gj … Gm BINS W1 W2 Wj … Wm

  14. HEURISTICS • PRIORITIZING THE SPATIAL GROUPS • : = SET OF ASSIGNABLE CCsFOR UE r IN GROUP Gi • i:= SET OF ASSIGNABLE CCs FOR GROUP Gi • PRIORITY METRIC := • LEAST PRIORITIZATION OF CELL-CENTER UEs IN RESOURCE ALLOCATION – COULD STILL GUARANTEE ALLOCATION OF GOOD CCs 800 G1 1525 G2 1800 Gj MGi 2025 … 2600 Gm

  15. PROOF OF CORRECTNESS – THE INTUITION • ASSIGNABLE RESOURCES FOR GROUP Gi : • ASSIGNABLE RESOURCES FOR GROUP Gj: • ASSUME GjGETS A HIGHER PRIORITY THAN Gi (by contradiction): • A,B,C COULD BE ASSIGNED TO Gj(worst case trafficrequirement) • ASSIGNABLE RESOURCES FOR Gi – EXHAUSTED (SHOULD BE SCHEDULED IN THE NEXT TIME SLOT) • IF Gi GETS A HIGHER PRIORITY THAN Gj • A,B,C COULD BE ASSIGNED TO Gi(worst case trafficrequirement) • D,E COULD STILL BE ASSIGNED TO Gj • HIGHER ADVERSE IMPACT FOR THE FORMER CASE – NOT A NEARLY OPTIMAL SOLUTION A B C B C D E A

  16. PRB ASSIGNMENT • GOAL • To allocate the best set of contiguouschannels to the UE groups • To minimizeresource contention and dependency on scheduling • Alreadyassignedresource/CC – considered for re-assignment to another group onlywhilelack of choice for the other group • FORMULATION: • Sum of estimatedbandwidths of UEs of group Gi • yij := Fraction of the total number of PRBs in CC j allocated to Gi • := Availablebandwidth in CC j for group Gi βij

  17. PRB ASSIGNMENT • Trafficrequirement for any group Gi: • Estimate the SINR, CQI and MCS – Spectral Efficiency values for all the PRBsacrosseachassignable CC for a given UE transmission power and pathloss model • Spectral Efficiencyisgiven by: • Channel allocation followsMaximum Throughputalgorithmusing the computed MCS levels

  18. SCHEDULING • TO RESOLVE CONTENTION AMONGST THE UE GROUPS AND INDIVIDUAL UEs • PHASE I : TIME DOMAIN-BASED INTER-GROUP PFPS • PROFILE-BASED TD METRIC: • SERVICE PRIORITIZATION COMMON RESOURCES t2 t1 G1 G2

  19. SCHEDULING INTRA-GROUP FREQUENCY-DOMAIN PFPS: UE with maximum FD metric : Total number of PRB combinations: UE1 UE3 UE2

  20. SIMULATION DETAILS • NS3 LENA – LTE/EPC NETWORK SIMULATOR • FULLY-IMPLEMENTED LTE UPLINK PHY AND MAC FUNCTIONALITIES • FEATURES INCLUDE MODELING THE AMC, PATH LOSS MEASUREMENTS, CHANNEL-STATE INFORMATION FEEDBACK • CELL SIZE 1 km • NON-ADJACENT FREQUENCY BANDS = 10 (5 CCs CHOSEN FOR CA) • FREQUENCY BANDS : 800, 1525, 1800, 2025, 2600 MHz • CONSTANT POSITION MOBILITY MODEL FOR eNB, CONSTANT VELOCITY MOBILITY MODEL FOR Ues • UNIFORM UE DISTRIBUTION ACROSS THE CELL • MAXIMUM 10 UEs PER CELL, (MAX. 5 HIGH-END TRAFFIC APPLICATIONS PER UE), GBR TRAFFIC APPLICATIONS • JAKES FADING MODEL, LOG NORMAL SHADOWING, 23 dBM UE TRANSMISSION POWER, 43 dBMeNB TRANSMISSION POWER, -120 dBM THRESHOLD PATH LOSS, -174 dBM/Hz NOISE SPECTRAL DENSITY

  21. TRAFFIC DETAILS

  22. RESULTS INTER- AND INTRA-GROUP PFPS (IMPR 15%, 21%) CC ASSIGNMENT (IMPR 33%, 15%)

  23. RESULTS CC ASSIGNMENT IN UNIFORM SCENARIO CC ASSIGNMENT (EDGE UEs) (IMPR. 64%, 54%)

  24. RESULTS INTER- AND INTRA-GROUP PFPS (EDGE UEs IMPR. 62%) UNIFORM CC ASSIGNMENT (EDGE UEs IMPR. 10%)

  25. RESULTS CDF OF LTE-A UPLINK THROUGHPUT (IMPR. 20%, SD 14%) ACHIEVED GBR (91.7%, 87.4%)

  26. DISCUSSIONLUSIONS • IMPACT ON POWER OPTIMIZATION : • ESTIMATED TRANSMISSION POWER FOR UE ON ANY CC: • LOW VALUES OF M AND PL FROM OUR PROPOSED MECHANISMS – MINIMIZES POWER CONSUMPTION • REST OF THE PARAMETERS ARE CC-SPECIFIC OPEN-LOOP AND CLOSED-LOOP VALUES • NOT APPLICABLE TO HIGH-SPEED MOBILE UEs – NO DISTINCT CELL-CENTER AND CELL-EDGE UEs, IRRELEVANT FEEDBACK • REQUIRES COORDINATION AMIDST MULTIPLE, NEIGHBORING eNBs

  27. CONCLUSIONS • CHANNEL- AND TRAFFIC-AWARENESS IN RESOURCE ALLOCATION FOR LTE-ADVANCED SYSTEMS • FOCUS ON UPLINK CARRIER AGGREGATION – CC ASSIGNMENT AND PFPS • MOTIVATION FOR GROUPING OF UEs • CC ASSIGNMENT – PROBLEM THEORETICALLY-MODELLED AS NP-HARD GENERALIZED ASSIGNMENT PROBLEM • PROPOSAL OF EDGE-PRIORITIZED CC ASSIGNMENT • PROPOSAL OF TIME-DOMAIN INTER-GROUP AND FREQUENCY-DOMAIN INTRA-GROUP PFPS • PERFORMANCE EVALUATION – 33% IMPR IN CC ASSIGNMENT AND 15% IMPROVEMENT IN SCHEDULING MECHANISMS • DOWNLINK LTE-ADVANCED MULTICAST, HIGH-SPEED SCENARIO – ENVISIONED FOR FUTURE WORK

  28. QUERIES??

  29. THANK YOU

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