Cell Tower Project
While E. Coyote is after the Road Runner. Mr. Coyote always gets lost in one particular area of town when his GPS cuts out because due to lack of signal â€“ no bars. Mr. Coyote contacted the service provider, ACME Wireless Communications, Inc. to complain. As a series of newly built neighborhoods and businesses are being built in this area and due to the customer complaints (including Mr. Coyoteâ€™s), your team has been assigned to design the cell tower that will be built to provide coverage in this area. As part of this design, you will need to maximize coverage area and minimize cost. Note that company bonus time is approaching and your bonus will be directly impacted by the quality of your design.
To help design the cell tower, please keep the followingin mind:
- Your system consists of a base station (cell tower), a mobile unit (cell phone), and the air link between them.
- While the electromagnetic signal flows in both directions (uplink â€“ mobile to base station and downlink â€“ base station to mobile), we will follow the engineering practice of assuming both links follow the same path â€“ thus, only calculate the downlink.
- Remember, your primary responsibility is to maximize coverage area.You are building only one tower.Select your tower location toâ€¦
- Maximize coverage area
- Consider distribution of subscribers / subscriber density. This will give you expected earnings per each geographic section you provide coverage.
- For the purposes of this assignment, consider an area covered that has a mobile unit received signal strength of -90dBm or better.
- To insure successful seamless coverage with the adjoining cell towers to the east, the right most geographic section must be fully covered. No cell towers exist to the west so there is no coverage requirement on the left geographic sections except to provide what is needed to maximize profit.
- One additional item. Your boss wants to know how much gross revenue your first choice design will generate.
- To simplify the problem, you will be working ONLY IN TWO DIMENSIONS.
- Required: Selection of first choice and second choice design (tower location and antenna recommendation for each). Note: In industry, communication engineers provide a prioritized list of multiple designs (tower locations) based on coverage.
- Produce Prx to area graph of both your first and second choice design. Due to the difficulties in establishing a trend line with a plot of this data distribution, for this project, you can plot your results in discreet points (even though as calculated data, graph is almost always a curve). Be sure to indicate location of your tower.
- Calculate monthly revenue (revenue per month) for both your top two designs.
Assumptions and equations:
- Assume all signal propagation from base station to mobile is line-of-sight.
- Cellular frequency = 850 MHz, thus for each wave, the is wavelength = 0.3529 m
- Height of the tower will be 250 ft. = 76.2m
- Path loss equation:
- L is path loss in dB
- Lambda is the wavelength in m
- D is the distance between mobile and base station antenna in m. Remember to use the correct equation (trigonometry??) to calculate distance from mobile to the top of the tower â€“ it is not the distance measured on the ground. While this calculation is only really needed when you are closer to the tower, you need to include it for all areas in case you move your tower during the design process.
- Link budget equation: Prx = Ptx + Gtx â€“ Ltx â€“ Lfs â€“ Lm + Grx – Lrx
- Prx = received power by mobile (dBm)
- Ptx = base station transmitted power (dBm): use 20 dBm
- Gtx = base station antenna gain (dBi)
- Ltx = base station cable and equipment power losses (dB): use 10 dB
- Lfs = path loss (dB)
- Lm = misc. losses (dB): use 5 dB
- Grx = mobile unit antenna gain (dBi): use 12 dBi
- Lrx = mobile unit internal component losses (dB): use 2 dB
- For your base station antennas, select from the below vendors. Note: you must include all vendors in your spreadsheet and identify your choice. Cell sites require 6 antennas per site (remember to multiply price by 6).
- ACME A096F Gain(dBi)=4.0 Price=$800
- ACME A325M Gain(dBi)=5.5 Price=$1381
- ACME A647A Gain(dBi)=7.0 Price=$1512
- ACME X157W Gain(dBi)=8.5 Price=$1850
- ACME X7468C Gain(dBi)=10.0 Price=$2000
- Average subscriber revenue = $10 per month. (Note: we are assuming $70 per month gross revenue per subscriber with $60 per month per subscriber costs associated with actually running the business.)
- Revenue (per month) = (Subscribers in areas covered) (Ave subscriber revenue per month)
Project 1 Report Requirements and Calculation Procedures
In setting up the excel spreadsheet, make sure you follow the guidelines I gave you in class.This will impact your grade.Â Also make sure you never type in values into your equations. Instead place those values in an input values location and use cell references to refer to the value. Do the same thing if you are using the results of a prior calculation in another calculation. Thus: when you change any input value, all your calculated data and your results would instantly update with no intervention by you.
- Heading: identify author, course, project, date, etc.
- Summary (opening) Paragraph: Brief summary of problem, and brief summary of solution including major numerical results
- Details of the problem
- Details of the results from your research
- Documentation of calculations
- Table of inputs, parameters, variables and constants, including units
- Conclusion:In the conclusion (final paragraph) of your memo, address the following reflection question: From doing this project, what you have learned: about using Excel, about engineering design, about cellular communications, about yourself?
- Attached project spreadsheet :
- Include in your spreadsheet required calculations, tables, and plots to create your design. Also include proper heading, problem statement, equations, brief conclusion.
This project is due on the day specified by your instructor prior to your class.Â Both a scanned copy of your printed report and your excel spreadsheet soft copy are required. ONE COPY PER TEAM.
Report â€“ Word File: Submit via Turn It In.I need from you your report as a word document with attached scanned spreadsheet print out embedded within your technical memo word file (the spreadsheet is part of your memo).You must follow the guidelines for a technical memo that I have posted.
Spreadsheet Soft copy â€“ Excel File: Submit via Blackboard.Submit ONLY your spreadsheet file (just click on the project tile in Blackboard to submit your file). Use the file name: EASC1112Proj1_YourName.xlsx. Of course you will put your name in the file name and not the generic â€œYourName.â€
Assume cell tower placed in exact middle of each area.
Assume all measurements (i.e. signal strength) done in exact middle of each area.