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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 SIMULATOR2. FULLY-IMPLEMENTED LTE UPLINK PHY AND MAC FUNCTIONALITIES3. 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