Self-­‐Op(misa(on  of  Ver(cal  Sectorisa(on  in  a  Realis(c  LTE  Network

EuCNC 2015, June 30, 2015, Issy les Moulineaux

Konstantinos Trichias, Remco Litjens (TNO) Abdoulaye Tall, Zwi Altman (Orange Labs)

Pradeepa Ramachandra (Ericsson Research)

§  Introduction §  Vertical sectorization (VS) §  SON for vertical sectorization §  Futur evolutions of VS §  Conclusions

Outline

2 SEMAFOUR

§ SON – Self Organizing Network

ü Self-configuration (simplify  deployment) ü Self-optimization (enhance  performance) ü Self-healing (manage  faults)  

§ SON deployment ü Centralized SON (C-­‐SON)  ü Distributed SON (D-­‐SON)    

Introduction (1/3)

3 SEMAFOUR

MROMLB

ICICES

RACH OptCCOCOC

ANR

LTE-AdvancedRelease >=10

LTERelease 8,9

Release  12

2013

§  Vertical Sectorization (VS) ü Active Antenna System (AAS) technology: RF components integrated in the antenna

§  UE beam stearing §  Separate Tx-Rx tilting §  Separate carrier tilting §  …

ü VS: the antenna can support two beams: two sectors with distinct cell ID ü A capacity solution: network densification

Introduction (2/3)

4 SEMAFOUR

§  Challenges for VS technology / deployment addressed in the SEMAFOUR project

1.  Type of deployment: network-wide or per cell 2.  What are the conditions to (de)activate VS to ensure performance gains as a

function of ü Traffic distribution ü Time reactivity ü Propagation, in terms of Vertical Angular Spread (VAS)

3.  What power allocation between inner and outer cells should be performed? 4.  Design simple SON algorithms for

ü VS (de)activation ü Power allocation

5.  What are possible evolutions of VS ü Virtual Sectorization (ViS)

Introduction (3/3)

5 SEMAFOUR

§  LTE network, 1800 MHz, 20 MHz bandwidth §  Environment: Urban and suburban §  Propagation: ray tracing §  Calculation zone: 5x7 km2, 63 sites §  Performance evaluation zone: 3x5 km2, 36 sites §  Traffic: Elastic

Hannover scenario

6 SEMAFOUR

§  Network-wide VS deployment

Vertical sectorizaton

7 SEMAFOUR

Performance results

8 SEMAFOUR

§  Gain for network wide deployment

§  VS at cell 52 (most loaded cell) only

Impact of propagation on performance

9 SEMAFOUR

Vertical Angular Spread

(degrees)

Average - Average user

throughput gain from VS

Average - 10th percentile user

throughput gain from VS

Average - Ratio Inner Sector /

Total size

7 < AS < 10 50.91% 132.45% 26.14% 4 < AS < 7 26.27% 73.98% 12.28%

AS < 4 10.96% 40.03% 5.69%

§  Angular spread

§  Analytical formulation (K. Trichias et al. “Performance evaluation and SON aspects of Vertical

Sectorisation in a realistic LTE network environment”, IWSON-IV, 2014)

§  The decision boundary is calibrated using measurements / simulations

–  When VS is off, estimation of inner and outer loads are required

(De)Activation VS SON

10 SEMAFOUR

ρinner

ρ outer

0 0.2 0.4 0.6 0.8 10

0.2

0.4

0.6

0.8

1

Decision boundary for VS OFFDecision boundary for VS ON

VS  ON

VS  OFF

§ 

(De)Activation VS SON – a simplified approach

11 SEMAFOUR

§  Allocated power depends on both –  The vertical sectorized cell –  Its neigbboring cells

§  SON algorithm:

–  Neighboring mobiles are considered if their path-loss to the serving BS is

smaller than 115 dB

Power Allocation SON

12 SEMAFOUR

§  Using VS (de)activation & Power Allocation SON

Results: capacity gain

13 SEMAFOUR

Gain  (high  load) No  VS Full  VSAverage 45% 9,50%10th  percentile 140% 26%

§  Generate a beam – virtual sector anywhere in the cell §  Technological challenges

–  Antenna optimization with high gain and low sidelobes –  SON for resource allocation / interference management –  Adapt beam location to traffic localization

Futur evolutions of VS: Virtual sectorization (ViS)

14 SEMAFOUR

z

x

yθ

−φ

φ

dx

dz

0 50 100 150 200-20

-10

0

10

20

30

40

θ

Ante

nna

gain

(dB)

E plane

-100 -50 0 50 100-20

-10

0

10

20

30

40

φ

Ante

nna

gain

(dB)

H plane

“Virtual-secorization: design and self-optimization”, in IWSON-V 2015

§  SON solutions can –  enhance VS performance:

§  (de)activation and power allocation SON –  allow selective VS (de)activation when conditions are present

§  Further promising evolution of AAS technology –  Virtual sectorization / small cells

Conclusions

15 SEMAFOUR