Effectiveness of Cell Outage Compensation in LTE Networks · 2018-12-29 · Effectiveness of Cell Outage Compensation in LTE Networks Mehdi Amirijoo, Ericsson, Sweden Ljupco Jorguseski,

Effectiveness of Cell Outage Compensation in LTE Networks

Mehdi Amirijoo, Ericsson, SwedenLjupco Jorguseski, TNO, The NetherlandsRemco Litjens, TNO, The NetherlandsRenato do Nascimento, Alcatel-Lucent, Portugal

CCNC ‘11January 10, 2011Las Vegas, USA

• INTRODUCTION• ASSESSMENT APPROACH• NUMERICAL RESULTS• CONCLUDING REMARKS

OUTLINE


OUTLINE

• LTE• Mobile cellular network technology• E-UTRAN, a.k.a. ‘Long Term Evolution’• Standardised by 3GPP R8-…• 3.9G successor to UMTS• Key features

• OFDM• MIMO• SON• …

INTRODUCTION

1989

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NMT 900

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+ HSDPA+ HSDPA2006

UMTSUMTS2003 UMTS

+ HSPA

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+ GPRS

LTE2011

INTRODUCTION

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MeasurementsDetection

Compensation

Operator policy:Coverage, QoS

Control parameters

Coverage/QoS map estimation

• Cell outage management / self-healing• Automatic detection and compensation of ‘outages’

• eNodeB failure, cell failure,physical signal/channel failure

• Enhances robustness/resilience

• Cell outage management / self-healing• Control parameters

• Transmit power settings• Antenna downtilt• Azimuth/beamforming• Scheduler’s fairness parameter• Intra/inter-RAT handover parameters, load balancing• Neighbour cell lists• …

INTRODUCTION


• Transmit power settings

INTRODUCTION

• PMAX = PPILOT + PDATA = fixed• Raising PPILOT increases coverage,

but decreases PDATA and hence thetraffic handling capacity/quality

• An increased coverage also impliesmore absorbed traffic, hence moreresource sharing and less per-user QoS

DOWNLINK

• P0 ≡ target received power density (per RB)• Reducing P0 lowers inter-cell interference

levels and hence increases coverage• Reducing P0 lowers the achievable MCS

and hence throughput/QoS per RB• An increased coverage also implies

more absorbed traffic, hence moreresource sharing and less per-user QoS

UPLINK


• Antenna downtilt

INTRODUCTION

• Raising TILT increases coverage,but also increases inter-cell interference

• An increased coverage also impliesmore absorbed traffic, hence moreresource sharing and less per-user QoS

• Objective

INTRODUCTION

TO ASSESS THE EFFECTIVENESS OF PPILOT, P0AND TILT IN MITIGATING THE EFFECTS OF CELL

OUTAGES IN DIFFERENT SCENARIOS


OUTLINE

• Scenarios• Diverse aspects are of potential interest …

• Site density• Traffic load• Service mix• Spatial traffic distribution• User mobility• Propagation environment• …

ASSESSMENT APPROACH

• Scenarios• COVL Coverage-oriented network layout with low traffic load• CAPL Capacity -oriented network layout with low traffic load• CAPM Capacity -oriented network layout with medium traffic load• CAPH Capacity -oriented network layout with high traffic load

ASSESSMENT APPROACH

Capacity-driven layout Coverage-driven layout

Inter-site distance 500 m 2200 m

Antenna downtilt 15o 5o

System bandwidth 10 MHz

PMAX,BS, PRS, PMAX,UE 46 dBm, 33 dBm, 25 dBm

Path loss 128.1 + 37.6 log10 r, with r in km

Shadowing σ = 8 dB, inter-site correlation of ½, decorrel. distance = inter-site distance / 15

Antenna model 3GPP 3D model

Noise level -199 dBW/Hz in DL, -195 dBW/Hz in UL

Service Generic elastic data service with a requested throughput of 1 Mb/s (DL) & 250 kb/s (UL)

• Performance metrics• Coverage probability• Uplink/downlink user throughput• Fraction of satisfied users, where ‘satisfied’ is …

• Covered• Uplink throughput ≥ α × 250 kb/s• Downlink throughput ≥ α × 1 Mb/s

• ... and α reflects the operator policy in thatit expresses the relative importance ofcoverage and quality

• When applicable, metrics areassessed over first tier of tellssurrouding the outage area

ASSESSMENT APPROACH


OUTLINE

PRE-OUTAGE SITUATION POST-OUTAGE SITUATIONWITHOUT COMPENSATION

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POST-OUTAGE SITUATIONWITH OPTIMISED PPILOT


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NUMERICAL RESULTS


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POST-OUTAGE SITUATIONWITH OPTIMISED P0


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NUMERICAL RESULTS


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POST-OUTAGE SITUATIONWITH OPTIMISED TILT


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NUMERICAL RESULTS

NUMERICAL RESULTSCOVERAGE-DRIVEN LAYOUT (LOW LOAD)

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pre-outage (reference) post-outage (nocompensation)

post-outage (optimisedtilt)

post-outage (optimisedP_0)

post-outage (optimisedP_RS)

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POST-OUTAGE(NO COMPENSATION)




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OUTLINE

• Cell outage management in LTE networks• Assessment of compensation potential of adapting …

• … PPILOT, P0 and the antenna downtilt

• Key insights• Both the compensation potential and the most effective control

parameter depend on the traffic load and the operator policy• P0 and the antenna downtilt are most effective in improving coverage• P0 and the antenna downtilt is most effective in improving user throughput

• Further research• Development of on-line algorthms for cell outage compensation

CONCLUDING REMARKS

ACKNOWLEDGMENT

ANNOUNCEMENT

Effectiveness of Cell Outage Compensation in LTE Networks · 2018-12-29 · Effectiveness of Cell Outage Compensation in LTE Networks Mehdi Amirijoo, Ericsson, Sweden Ljupco Jorguseski,

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