ANCIT WORKSHOP Torino, 30-31 March 1998 Cost optimisation of optical access networks Peter Hale, Martin Davies Pirelli Cables, UK David Brittain University.

ANCIT WORKSHOPTorino, 30-31 March 1998

Cost optimisation of opticalaccess networks

Peter Hale, Martin DaviesPirelli Cables, UK

David BrittainUniversity of Bristol, UK

ANCIT WORKSHOPTorino, 30-31 March 1998

Summary

• Conventional cables or Blown Fibre?

• ‘Simple’ analysis

– Results– Further work

• ‘Comprehensive’ analysis

– Genetic algorithms– Results

• Conclusions and discussion

ANCIT WORKSHOPTorino, 30-31 March 1998

Conventional or Blown Fibre?

• Optical fibre in the access network

– Must be cost-effective

• Alternative approaches

– Conventional loose-tube?– Blown Fibre?

• Generic approach to modelling

– ‘Simple’– ‘Comprehensive’

ANCIT WORKSHOPTorino, 30-31 March 1998

‘Simple’ analysis

• Considers component costs

• Methodology

– Feeder network

– Distribution network

• Building blocks

– Spines

– Stars

• Planning

– Less simple with Blown Fibre

PlanDucts &

manholesInstall

subductInstallcables

Installplant

Fibre routing& splicing

Test

PlanDucts &

manholes

Installtube

assemblies

InstallBF unit

Installplant

Fibre routing& splicing

Test

Conventional cable (CW & RLT)

Blown Fibre

?

ANCIT WORKSHOPTorino, 30-31 March 1998

Spines and stars

ANCIT WORKSHOPTorino, 30-31 March 1998

Results

Spine

Star

Cumulative Costs

£-

£2,000£4,000

£6,000

£8,000£10,000

£12,000

Year 0 Year 1 Year 2 Year 3 Year 4 Year 5

CW 48 Spine

Blown 4 Spine

Cumulative Costs

£-

£1,000

£2,000

£3,000

£4,000

£5,000

Year 0 Year 1 Year 2 Year 3 Year 4 Year 5

CW 48 Star

Blown 4 Star

ANCIT WORKSHOPTorino, 30-31 March 1998

‘Comprehensive’ analysis

• Genetic Algorithm (GA) approach

– Based on biological evolution

• Operators

– Crossover– Mutation

• Detailed costing approach

..0 1 1 0 0 1 Mother

..1 1 0 1 0 0 Father

..0 1 0 1 0 0 Sister

..1 1 1 0 0 1 Brother

Genes ‘swapped’from here

ANCIT WORKSHOPTorino, 30-31 March 1998

Basis of model

• Outline of costing approach

– Cable and plant– Installation costs– Net present value– Price erosion

• Does not include

– Disposal costs at end of life– Duct and sub-duct costs

ANCIT WORKSHOPTorino, 30-31 March 1998

GA costing spreadsheet

ANCIT WORKSHOPTorino, 30-31 March 1998

GA network map

Exchange

Primary node

Primary node SPossiblesecondarynode site

StCustomersite

Duct

ANCIT WORKSHOPTorino, 30-31 March 1998

GA - cost versus generation

40000

42000

44000

46000

48000

50000

52000

54000

56000

58000

60000

1 101 201 301 401 501

Generation

No

rmal

ised

Net

Pre

sen

t V

alu

e

Blown Fibre

Blown Fibre Best

Conventional

Conventional Best

ANCIT WORKSHOPTorino, 30-31 March 1998

GA solutions - 1

Conventional cable Blown fibre

ANCIT WORKSHOPTorino, 30-31 March 1998

GA solutions - 2

Conventional cable

Blown Fibre

• Some nodes have same position

• One additional node for conventional cable

ANCIT WORKSHOPTorino, 30-31 March 1998

Topology - differences and features

• Cost differences

– Generally conventional cable installed earlier– Blown Fibre installed just-in-time– Blown Fibre plant generally less expensive

• Node placement

– Additional conventional node• Deferred installation saves cost

– ‘Cluster’ of customers around nodes

ANCIT WORKSHOPTorino, 30-31 March 1998

GA cost resultsCumulative costs

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

1 2 3 4 5 6 7 8 9 10 11

Year

Blown Fibre

Coventional Cable

ANCIT WORKSHOPTorino, 30-31 March 1998

Conclusions and discussion

• Blown Fibre more cost effective

– Both models– Less labour– Blow through joints - no splice trays/splices– Less plant - only install required fibres– Just-in-time installation

• Topology differences

– Ability to defer costs