EDGE-PRIORITIZED CHANNEL- AND TRAFFIC-AWARE UPLINK CARRIER AGGREGATION IN LTE-ADVANCED SYSTEMS...
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Transcript of EDGE-PRIORITIZED CHANNEL- AND TRAFFIC-AWARE UPLINK CARRIER AGGREGATION IN LTE-ADVANCED SYSTEMS...
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EDGE-PRIORITIZED CHANNEL- AND TRAFFIC-AWARE UPLINK CARRIER
AGGREGATION IN LTE-ADVANCED SYSTEMSAUTHORS
R. SIVARAJ, A. PANDE, K. ZENG, K. GOVINDAN, P. MOHAPATRA
PRESENTERR. SIVARAJ,Ph.D student in CS,UC DAVIS, CA, USAEmail: rsivaraj AT ucdavis DOT eduhttp://spirit.cs.ucdavis.edu
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AGENDA OF THE PRESENTATION
INTRODUCTION ISSUES IN EXISTING LITERATURE PROBLEM STATEMENT KEY CONTRIBUTIONS WHY UPLINK? SYSTEM MODEL CARRIER AGGREGATION SCHEDULING PERFORMANCE EVALUATION DISCUSSION CONCLUSION
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INTRODUCTION TO LONG TERM EVOLUTION
800 MHz
1525 MHz
1900 MHz
2025 MHz
2600 MHz
10 MHz CC
15 MHz CC
20 MHz CC
5 MHz CC
1.4 MHz CC
90
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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)
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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
MACMACMAC
CC CC CC
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ISSUES IN EXISTING LITERATURE
I wanna stream a HD video
Am in here for a video conferencing
A VoIP call to my manager
Ah !!!! Jus wanna surf Facebook
Send an email to my boss applying for leave
Video gaming with my friends for the next half-hour
Edge UEs contribute to a bulkier data
Center/Close to center UEs contribute to less UL traffic
Now I wanna surf Facebook
Same number of resources for both ?
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Grouping of UEs based on spatial correlation – Similar channel conditions and radio characteristics
UE GROUPING
CQI
CQICQI
CQI
CQI
CQI
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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
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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
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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
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CALCULATEAMBR
SYSTEM MODEL
NON-ADJACENT INTER-BAND CARRIER AGGREGATION (800 MHz, 1525 MHz, 1800 MHz, 2025 MHz, 2600 MHz)
FOR ANY UE, ASSIGNABLE CC SET 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
QCI
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DISTRIBUTION OF ASSIGNABLE CCs TO UEs
CC1
CC2
CC3
CC4
CC5
UE1
UE2
UE3
UE4
UE5
N
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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 ASSIGNED TO THE BINS
FEASIBLE SOLUTION: SOLUTION WITH MAXIMUM PROFIT (ACHIEVED UPLINK THROUGHPUT)
CC1 CC2 CCi … CCn ITEMS
BINSG1 G2 Gj … Gm
W1 W2 Wj … Wm
pijβij
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HEURISTICS
PRIORITIZING THE SPATIAL GROUPS : = SET OF ASSIGNABLE CCs FOR 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
1525
1800
2025
2600
G1
G2
Gj
…
Gm
MGi
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PROOF OF CORRECTNESS – THE INTUITION
ASSIGNABLE RESOURCES FOR GROUP Gi :
ASSIGNABLE RESOURCES FOR GROUP Gj :
ASSUME Gj GETS A HIGHER PRIORITY THAN Gi (by contradiction):
A,B,C COULD BE ASSIGNED TO Gj (worst case traffic requirement)
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 traffic requirement)
D,E COULD STILL BE ASSIGNED TO Gj
HIGHER ADVERSE IMPACT FOR THE FORMER CASE – NOT A NEARLY OPTIMAL SOLUTION
A B C
A B C D E
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PRB ASSIGNMENT
GOAL To allocate the best set of contiguous channels to the UE groups To minimize resource contention and dependency on scheduling Already assigned resource/CC – considered for re-assignment to another
group only while lack of choice for the other group FORMULATION:
Sum of estimated bandwidths of UEs of group Gi
yij := Fraction of the total number of PRBs in CC j allocated to Gi
:= Available bandwidth in CC j for group Gi βij
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PRB ASSIGNMENT
Traffic requirement for any group Gi :
Estimate the SINR, CQI and MCS – Spectral Efficiency values for all the PRBs across each assignable CC for a given UE transmission power and path loss model
Spectral Efficiency is given by:
Channel allocation follows Maximum Throughput algorithm using the computed MCS levels
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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
G1 G2
COMMON RESOURCES
t1t2
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SCHEDULING
INTRA-GROUP FREQUENCY-DOMAIN PFPS:
UE with maximum FD metric :
Total number of PRB combinations:
UE1 UE3 UE2
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SIMULATION DETAILS1. NS3 LENA – LTE/EPC NETWORK SIMULATOR
2. FULLY-IMPLEMENTED LTE UPLINK PHY AND MAC FUNCTIONALITIES
3. 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 dBM eNB TRANSMISSION POWER, -120 dBM THRESHOLD PATH LOSS, -174 dBM/Hz NOISE SPECTRAL DENSITY
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TRAFFIC DETAILS
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RESULTS
CC ASSIGNMENT (IMPR 33%, 15%) INTER- AND INTRA-GROUP PFPS (IMPR 15%, 21%)
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RESULTS
CC ASSIGNMENT IN UNIFORM SCENARIO CC ASSIGNMENT (EDGE UEs) (IMPR. 64%, 54%)
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RESULTS
INTER- AND INTRA-GROUP PFPS (EDGE UEs IMPR. 62%)
UNIFORM CC ASSIGNMENT (EDGE UEs IMPR. 10%)
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RESULTS
CDF OF LTE-A UPLINK THROUGHPUT (IMPR. 20%, SD
14%)
ACHIEVED GBR (91.7%, 87.4%)
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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
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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
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QUERIES??
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THANK YOU