ancit workshop torino, 30-31 march 1998 cost optimisation of optical access networks peter hale,...
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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