1. Homework 3
Wireless Infrastructure Deployment and Economics
IK2514
Dimensioning and cost structure analysis of wide area
data service network
Asfak Rahman
asfak@kth.se

2. Introduction
The task of this report is to dimension and design a radio access network for a new operator
‘Greenfield’ in the urban area of Little Belgium. The operator has three types of RAT
deployment options and a required coverage plan to be fulfilled within timeline. First, user
demand is calculated considering the expected penetration rate. Then network dimensioning is
adjusted for the required capacity in each year. Finally, a close comparison is conducted among
deployment options in term of cost and most optimal solution is suggested to the ‘Greenfield’
operator.
User demand Calculation
The target urban area is 1000 km2. This area has to be covered by the operator within 5 years. A
yearly penetration rate has been provided to determine the expected users in that particular
area.
Coverage and User Expectation
year 0 1 2 3 4 5
Covered area % 0 20% 40% 60% 80% 100%
Area,km2 0 200 400 600 800 1000
Users 0 400000 800000 1200000 1600000 2000000
Penetration rate 0 10% 15% 20% 20% 20%
Expected users 0 40000 120000 240000 320000 400000
The total traffic is assumed to be concentrated to 4 hours per day and monthly average data
usage is provided. So data rate per user can be achieved by the equation “Data rate = 8*(Usage
per user)/30*60*60*4 “.At the beginning of first year there is no deployed network, so total
demand of data rate is concentrated to null.
User Demand
year 0 1 2 3 4 5
Usage per User(GB/month) 1 1.2 1.4 1.6 1.8 2
Data rate per User, Mbps 0 0.023 0.027 0.03 0.034 0.038
Expected Users 0 40000 120000 240000 320000 400000
Total require data rate, Mbps 0 920 3240 7200 10880 15200
Data Rate Mbps/km2 0 4.6 8.1 12 13.6 15.2

3. Cost structure description
As a new operator, the network has to be deployed from the scratch. Available RAT solutions
are UMTS macro, UMTS micro and WLAN.
Radio Access Network
RAT deployment Cell range(Urban)
UMTS Macro 0.6 km
UMTS Micro 0.15 km
WLAN 0.03 km
UMTS macro has same capacity as UMTS micro, but has better coverage and the price of the
BTS and installation cost is double than UMTS micro. WLAN is quite cheap to deploy, but with a
very poor coverage. Some thousands of sites would be needed to deploy WLAN technology in a
short area. Overall building the network will be cheaper for WLAN and UMTS micro compared
to UMTS macro. But there is a possibility of high OPEX due to huge amount of sites.
Network Modeling
Capacity, cost structure and NPV calculation are considered in network modeling section. Since
a new network is being planned to be deployed, site based capacity model would be more
appropriate for calculations. The cell size is assumed as a hexagon. The area of a hexagon is
3*sqrt(3)*R2/2,where R is the radius of a cell. For simplicity network dimensioning is produced
for each RAT solutions individually.
UMTS macro
The range of one UMTS macro BTS is 0.6 km. So the area covered by one site is 0.935 km2.
Capacity of one BTS is 1 Mbps and maximum capacity of one site is 6 Mbps (3-sectors with 2
carriers each). From the user demand table we can found that we would be out of the
maximum capacity in 2nd year of deployment. So sites should be placed more condensed
manner to meet up with the maximum capacity limit. For this purpose a statistical approach is
being taken under consideration and transmission power is adjusted to recover the optimal cell
coverage of 0.39 km2 (required capacity of one site in 5th year =0.39*15.2 = 5.928 Mbps ). No
future data rate demand is taken under consideration in this report.

4. The table below shows that required capacity is being met by increasing the number of sectors
and carriers to the deployed sites every year. Leased line capacity is 2 Mbps. From 2nd year
leased line capacity is incremented with the growing demand of data rates.
Capacity calculation, UMTS macro
year 0 1 2 3 4 5
Area,km^2 0 200 400 600 800 1000
Total number of sites 0 513 1026 1538 2051 2564
Additional Carrier/sectors 0 2 4 5 6 6
Total Capacity, Mbps 0 1026 4104 7690 12306 15384
Total required capacity, Mbps 0 920 3240 7200 10880 15200
Capacity per site, Mbps 0 2 4 5 6 6
Required Capacity per site, Mbps 0 1.8 3.16 4.7 5.3 5.9
Required leased lines E1 0 1 2 3 3 3
The cost table contains information about the CAPEX and OPEX. Every year old sites are
upgraded with more sectors/carriers. In the final year no upgrade is done. So the CAPEX is
lower than previous years.
Cost Table for UMTS Macro
CAPEX
year 0 1 2 3 4 5
number of sites each year 0 513 513 512 513 513
Additional sectors/carriers 0 1026 3078 3586 4616 3078
BTS cost 0 10260 10260 10240 10260 10260
Carrier cost 0 10260 30780 35860 46160 30780
site installation cost 0 15390 15390 15360 15390 15390
Data line installation cost 0 2565 2565 2560 2565 2565
Site Build-out cost 0 20520 20520 20480 20520 20520
Total 0 58995 79515 84500 94895 79515
Price erosion 0% 5% 5% 5% 5%
CAPEX,K Euro 58995 75539.25 80275 90150.25 75539.25
OPEX
Site Lease cost 0 4104 8208 12304 16408 20512
Leased line E1 cost 0 513 2052 4614 6153 7692
Electricity cost 0 2052 8208 15380 24612 30768
Operation & maintenance cost 0 5899.5 7553.925 8027.5 9015.025 7553.925
Total OPEX, K Euro 12568.5 26021.93 40325.5 56188.03 66525.93

5. UMTS micro
The range of one UMTS micro BTS is 0.15 km. So the area covered by one site is 0.06 km2.
Capacity of one BTS is 1 Mbps. The coverage area is very small with high capacity. So we can
directly apply the per site based capacity model. Usually micro BTS is used to cover a small
uncovered area where the penetration loss is high and SNR does not meet as required. But a
network dimensioning model is created to analyze the impact of full coverage by UMTS micro
solution. From the table, we can see that we do not need to upgrade sites with additional
sectors or carriers.
Capacity calculation, UMTS micro
year 0 1 2 3 4 5
Area,km^2 0 200 400 600 800 1000
Total number of site 0 3334 6667 10000 13334 16667
Additional Carrier/sectors 0 0 0 0 0 0
Total Capacity, Mbps 0 3334 6667 10000 13334 16667
Capacity per site, Mbps 0 1 1 1 1 1
Required Capacity per site, Mbps 0 0.276 0.486 0.72 0.816 0.912
Cost table is provided below.
Cost Table for UMTS Micro
CAPEX
year 0 1 2 3 4 5
number of BTS per year 0 3334 3333 3333 3334 3333
Additional Carrier 0 0 0 0 0 0
BTS cost 0 33340 33330 33330 33340 33330
Carrier cost 0 0 0 0 0 0
site installation cost 0 66680 66660 66660 66680 66660
Data line installation cost 0 16670 16665 16665 16670 16665
Site Build out cost 66680 66660 66660 66680 66660
Total 183370 183315 183315 183370 183315
Price erosion 0% 5% 5% 5% 5%
CAPEX,K Euro 183370 174149.3 174149.3 174201.5 174149.3
OPEX
Site Lease cost 0 13336 26668 40000 53336 66668
Leased line E1 cost 0 3334 6667 10000 13334 16667
Electricity cost 0 666.8 1333.4 2000 2666.8 3333.4
Operation & maintenance cost 0 18337 17414.93 17414.93 17420.15 17414.93
Total OPEX, K Euro 35673.8 52083.33 69414.93 86756.95 104083.3

6. WLAN
WLAN is a technology developed for small coverage area with high data throughput. Usually it
is developed for home users to have internet connectivity wirelessly. But there are some
example of large projects implemented with WLAN. The given cell range is 0.03 km. Then
assuming hexagonal cell ,the coverage area would be 0.00234 km2. Since the cell size is very
small, we will need huge amounts of BTS to cover provided area.
Capacity calculation, WLAN
year 0 1 2 3 4 5
Area,km^2 0 200 400 600 800 1000
Total number of BTS 0 85470 170940 256410 341880 427350
Additional Carrier/sectors 0 0 0 0 0 0
Total Capacity, Mbps 0 85470 170940 256410 341880 427350
Capacity per site, Mbps 0 10 10 10 10 10
Required Capacity per site, Mbps 0 0.0013 0.0023 0.0035 0.004 0.0045
As we have good capacity in each BTS, we just have to cover the whole area by adding new BTS
each year. Finally, a cost table is produced to calculate the CAPX and OPEX yearly. Interesting to
mention that OPEX is higher than CAPEX due to huge number of BTS has been deployed and
their maintenance is costly than BTS itself.
Cost Table for WLAN
CAPEX
year 0 1 2 3 4 5
number of BTS per year 0 85470 85470 85470 85470 85470
Additional Carrier 0 0 0 0 0 0
BTS cost 0 85470 85470 85470 85470 85470
Carrier cost 0 0 0 0 0 0
site installation cost 0 256410 256410 256410 256410 256410
Data line installation cost 0 0 0 0 0 0
Site Build-out cost 0 0 0 0 0
Total 341880 341880 341880 341880 341880
Price erosion 0% 5% 5% 5% 5%
CAPEX,K Euro 183370 324786 324786 324786 324786
OPEX
Site Lease cost 0 85470 170940 256410 341880 427350
Leased line E1 cost 0 85470 170940 256410 341880 427350
Electricity cost 0 1709.4 3418.8 5128.2 6837.6 8547
Operation & maintenance cost 0 18337 32478.6 32478.6 32478.6 32478.6
Total OPEX, K Euro 190986.4 377777.4 550426.8 723076.2 895725.6

7. NPV calculation
NPV calculation is computed form the cost table of three deployment options for whole 5
years. For this purpose a high discount rate of 10% is used. The graph below shows the cash
outflows for each RAT deployments. From the graph we can see that UMTS macro has low cash
outflows than the other two technologies. So UMTS macro would be an optimal option to
deploy due to low risk and high profitability.
profita
3500000
3000000
2500000
2000000 UMTS macro
UMTS micro
1500000
WLAN
1000000
500000
0
1 2 3
Conclusion
After taken consideration of CAPEX, OPEX and NPV calculation, we can come to the conclusion
that UMTS macro is more appropriate to deploy rather than other two technologies. But
neither of all these RAT solutions are appropriate alo
alone. Because we have calculated the users
are uniformly distributed in our geographical area. In real time the user distribution would be
different depending of geographical areas. So more optimal solution would be to deploy the
network with integrate UMTS macro and UMTS micro.