This document summarizes a student project to create a wireless drone network. The goals were to use drones and base stations to efficiently search large areas and provide backup cell service. Key elements included a secondary drone for video streaming, a primary drone for routing video over multiple hops, and base stations for control and modulation. The project encountered difficulties with incompatible software, configuration issues, and hardware assembly. Overall it provided valuable experience with wireless networking concepts and protocols despite challenges in implementation. Lessons learned included the importance of thorough planning, documentation, and learning from past projects.

1. 1

2. Outline
• Goal of Project
• Expectations, Results, Difficulties:
▫ Video Drone
▫ Primary Drone
▫ Base Station
• Lessons Learned
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3. Goal of Project
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4. Real Life Scenario
Problem Statements:
• Be able to search larger areas more efficiently
(Conducting SAR’s )
• Locate lost hiker in Yosemite park
• A need for quick cell tower coverage back up
for an entire disaster area

5. Objective
• Create an environment for students to explore
and learn about wireless networking
▫ Routing methodologies
▫ Software Defined Radio
▫ Cognitive Algorithms
▫ Wireless communication protocols

6. Secondary Drone
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7. Secondary Drone- Expectation
• Live video stream transmitted to base station
• Remotely controlled by PS3 controller
• Detect person 20ft. below
• H.264 video codec
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8. Secondary Drone- Results
• Remotely controlled by PS3 controller
• Recorded video used at base station
• Person detected 20ft. below
• H.264 video codec
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9. Technical Difficulties
• Drone software required intermediate level
experience in Linux
• PS3 controller required additional
configuration coding
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10. Primary Drone
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11. Primary Drone- Expectation
• Computer
▫ Routing w/minimum of 2 hops
• FPGA
▫ Digital Down Conversion
▫ Digital Up Conversion
▫ Ethernet Connection
▫ Connection to RF Front End
• RF Front End
▫ RX & TX
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12. Routing- Expectations
• Utilize existing MAC management software:
OpenWrt/Click Modular Router
• Tether MAC software with GNU Radio
Companion to create multilayer network
• Utilize Open OSLR as Protocol
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13. Technical Difficulties
• Software not compatible with radio drivers
• GNU radio not compiling on Raspberry Pi
• No platform to run Open OSLR
• Majority of example codes done for simulations
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14. Routing- Results
• Simulated P2P network with user constraints
• Programmed in C code compiles on gcc compiler
• Generates path of shortest distance
• Simulated nodes behave independently
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15. Routing- Future Alterations
• Allow for arguments from device
• Integrate with physical layer software
• Make the path dynamic and recoverable
• Add encryption
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16. FPGA- Expectation
• Vector Sinusoid
• FIR Filter
• CIC Filter
• Ethernet connection
• VHDCI Connection
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17. FPGA- Vector Sinusoid
• 15MHz 13.125MHz = 1.875MHz IF
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18. FPGA- FIR Filter
• MATLAB
• 7th Order FIR Filter
• Hamming Window Filter
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19. FPGA- Technical Difficulties
• Ethernet Connection
• VHDL syntax and flow
• Bringing theory to practice
• Analog to Digital Converter not
fucntioning
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20. RF Front End Expectations
• Facilitate Rx & Tx functions
▫ PA/LNA, IF mixing
▫ WB operation
▫ simplex operation
▫ 10-bit ADC/DAC
▫ Integration with FPGA
▫ PCB board/antenna
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21. RF Front End- Results
• Programmable IF mixing
▫ WB mixing, narrow band RF chip
▫ Mixer development board vs. custom PCB
• Tx & Rx files on basestations
▫ Using Ettus radio as signal source
• Laptop serial interface in place
FPGA logic control
▫ LO programing
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22. Technical Difficulties
• Surface mount chip
▫ Almost impossible by hand
▫ QFN PCB/low temp solder paste
• High frequency board layout
▫ Lack of PCB + breadboard
▫ Troubleshooting due to these issues
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23. Base Station
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24. Base Station- Expectations
• Ubuntu OS partitioned with Windows OS
• Drone linked to FFMPEG to link with GNU Radio
• Drone software functioning to control drone
• BPSK and QPSK modulation used to send H264
video between base stations
• Channel Coding
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25. Base Station- Results
• Ubuntu partitioned with
Windows
• Drone software
• BPSK used to send
H264 video
• FFMPEG connection
with drone
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26. Base Station- Results
Noisy Plots BPSK RX Plots
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27. Technical Difficulties
• Lack of software
documentation
• Data cutoff of
TX/RX files
• Modulation techniques
unstable
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28. Error Correction Codes
• Decrease in the SNR necessary to obtain desired
BER
• Redundancy from parity bits
▫ use n symbols to send k symbols of data
• Expectations:
▫ Block and/or trellis coding through GRC blocks
▫ Reed-Muller-Golay channel coding toolbox

29. Error Correction Coding- Results
• GRC’s error correction coding blocks have no
documentation
• Chancoding toolbox showed promise, but we
couldn’t get it installed on the base stations
• Simulation written in C:
▫ Hamming(7,4) is used to encode a message
▫ Message is corrupted with noise, then decoded

30. Message
to
Transmit
Encoded
Message
Modulated
Encoded
Message
Noisy
Received
Message
Received
Encoded
Message
Received
Message
Simulated
Noisy
Channel
GNU Radio
and Antennas
Encoding
Algorithm
Decoding
Algorithm
Binary
to NRZ
NRZ to
Binary

31. Direct Sequence
Code Division Multiple Access
• Allows multiple users to occupy one channel
▫ Unique user code distinguishes each user
• Signature is a pseudorandom sequence
▫ Spreads the data over wider bandwidth
▫ Resembles noise

32. Multiple Access Channel Coding
• Expectation:
▫ CDMA- possibly with pseudorandom codes
• Results:
▫ Simple CDMA with Walsh-Hadamard matrix
▫ Rows of the Walsh-Hadamard matrix form an
orthogonal basis
▫ Four messages are encoded, “transmitted,” and
separated

33. Character 8 Bits 32 Bits
+ 32 Bits
Encode
Decode
Character
Multiple encoded
messages are
transmitted at the
same time
8 Bits
Each signature will
decode a different
message from the total
Each message takes four times as long to send, but all four are transmitting at
the same time. The messages can’t be read unless the signatures are known.

34. Productivity Summary
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35. 35
Gantt Chart

36. Costs
Item Projected Cost Actual Cost
RF Board:
Low Noise Amplifier, ADC, DAC,
Mixer Development Board, 2.4 GHz
Antenna
$100 $285
Base Station Peripherals:
PS3 Controller and Bluetooth Dongle
$45 $45
AR Drone $300 $300
FPGA
Spartan 6 and Expansion Board
$240 $240
Miscellaneous Materials
and Shipping Costs
$150 $90
Total $835 $960
“Freebies”
Base station computers, Ettus radios
and antennas
Valued at $7000

37. Experience Gained
• N210 Radios
• Linux
•
•
• VHDL
• PCB Layout
• MATLAB
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38. Lessons Learned
• Software is not predictable
• Free software often has little documentation
making troubleshooting difficult
• The best way to learn is to learn from others’
mistakes (previous research projects)
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39. Lessons Learned
• Think outside the box when troubleshooting
• Know what you don’t know
• Always have a plan B and C…and D
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40. Team Assessment
• Team organization
▫ Coordination
▫ Project goals
• Team communication
▫ Task division
• Team dynamic
▫ Idea conflicts
▫ Overall our team supported each other
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41. Thank You!
• And a special thanks to…
▫ Families & Friends
▫ Dr. Busch
▫ Mr. Youmans
▫ Mr. Wright
▫ Dr. Urban
▫ Dr. Smolenski
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