Chris Monfredo Chris Johnson Jon Holton Greg Davis Scott Hambleton
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Transcript of Chris Monfredo Chris Johnson Jon Holton Greg Davis Scott Hambleton
Chris MonfredoChris JohnsonJon HoltonGreg DavisScott Hambleton
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P14251Underwater Acoustic Communication
Underwater Acoustic Communication
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AgendaRevisit Customer and Engineering RequirementsFunctional DecompositionMorphological Charts
Morph DetailsPugh Analysis
Final Pugh AnalysisFinal System SelectionRisk AnalysisTest PlansSubsystem Design Schedule
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Underwater Acoustic Communication
Customer Requirements
Most important requirements:Customer Rqmt. #
Importance Description
CR1 9 Send signalCR2 9 Send signal at a rate in kb/sCR3 9 System must function underwaterCR4 9 Reliable communication schemeCR5 9 Communications must resist frequency contaminationCR6 9 Must have 2-way communication capabilities
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Engineering Requirements
Most important requirements:
Rqmt. # Priority Source Engr. Requirement (metric)Unit of
MeasureTolerance Value (+/-)
Nominal Value
Comments/StatusTest (how are you going to verify
satisfaction)S1 9 CR1 Signal Range m 5/5 30 Pool TestS2 9 CR2 Signal Rate kb/s 5 15 Pool TestS3 9 CR4 Probability of error in signal % 0/10 <10 Remove error detect/correctS4 9 CR4 Bit error detection % Compare with on vs offS5 9 CR4 Bit error correction % Compare with on vs offS6 9 CR3,CR9 Water resistant/sealed Y/N Y Hose test
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Functional DecompositionAcoustic
Communication System
Requires Power
Send Message
Receive Message
Functions Underwater
Power Converters
Generate Digital
Message
Convert Message to
Analog
Modulate Signal
Transmit Signal
Detect SignalDemodulate
Signal
Convert Message to
Digital
Analyze Message
Sinks Underwater
Water Resistant
Corrosion Resistant
Pressure Resistant
Input Data Unpack DataEncode DataCompress
DataEncrypt Data
Decompress Data
Decrypt Data
Heat Sinking
Pack DataError Check, Correct, and Decode Data
Output Data
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System Flow Diagram
Unpack DataDecompress Data
Decrypt DataError Check, Correct, and Decode Data
Output Data
Input Data Encode DataCompress Data Encrypt Data Pack Data Modulate Signal Transmit SignalComputer
Computer Receive SignalDemodulate
Signal
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Communication Protocols: ALOHA
• Easy to Implement• Inefficient – Theoretical throughput of 18%
(36% for slotted ALOHA)• Better suited for long distances
StartAssemble a Frame
of DataTransmit Data
Back off for random amount of
time
Collision? EndNO
YES
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Communication Protocols: CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance)
• Less Noise• Better Throughput• Can function with swarm expansions• Terminal Problems vs. Overhead
StartAssemble a
Frame of DataChannel
Idle?
Back off for random amount
of time
Transmit Request to Send (RTS)
Clear to Send (CTS) Received?
Transmit Data End
NO
NO
YES
YES
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Communication Protocols: CDMA(Code Division Multiple Access)
- Sends data in a unique frequency pattern - Receiver can intercept multiple signals and decode
based on the pattern
- Allows multiple, simultaneous senders with same set of frequencies• Widely-Used by 2G and 3G Devices• High Throughput• Difficult to Implement• Difficult to test – Requires more than two devices
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Error Detection and CorrectionDetection Methods:Parity BitsCyclic Redundancy Checks (CRCs)Error Correcting Code (EEC)
Correction Methods:Automatic Repeat Requests (ARQs)Forward Error Correction (FEC)Hybrid Schemes (Both ARQ and FEC)
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Encryption and CompressionEncryption Methods: Triple DES (56-bit) AES (128-bit) If not enough time, something simple (XOR the bit stream)
Compression Methods: Lossless Algorithms Lossy Algorithms
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Computational PowerMicroprocessors: Low Price Low Complexity Efficient Fairly Versatile Many microprocessors to choose from
Other options (regular processors, FPGAs, ASICs) are too expensive, complicated, and far beyond the scope of this project.
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Power ConvertersTransformer
High voltage step-down or positive and negative voltage
Buck Converter High efficiency step-down
Linear Regulator Easy to implement but low efficiency
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Amplitude Modulation
Easy to ImplementRequires more power than other schemesCarrier frequency must be about 10X data rate
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Frequency Modulation
Susceptible to frequency shifts due to Doppler effect or sound speed changesCarrier frequency is move flexible than AM
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Phase Shift Keying
Harder to implement than FM but more resistant to noiseMore bandwidth efficient than FM
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Quadrature Amplitude Modulation
Hardest to implementCan encode the most amount of informationSusceptible to noise
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Corrosion ResistantMaterial Selection
Metals Plastics
Corrosion Resistant Coating Barrier Galvanization
Water ResistanceGasket/O-ringsCaulk/SealantTight Fit
Pressure ResistanceStructural Strength/Case DesignInternal Pressurization
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Dissipate HeatHeat sinkFanLiquid cooling
Use external water Use internal system
Image from: http://en.wikipedia.org/wiki/File:Heatsink_povray.png
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Morphological ChartPower Converters Transformer Buck Converter Linear Converter
Data Input Computer Auto-GeneratedError Detection Parity bits CRCs EECs
Error Correction ARQs FECs Hybrid Scheme(De)Compression Lossless Algorithms Lossy Algorithms
(De)Encryption XOR the bit stream Triple DES AESComm. Protocol CSMA/CA Aloha CDMA Custom Design(De)Modulation AM FM Phase QAM
Sinks Underwater Internal Weight External WeightWater Resistant O-Rings Metal-on-Metal Sealant Glue
Corrosion Resistant Metal Selection Coatings Plastic SelectionPressure Resistant Case Design Internal Presure
Dissipate Heat Heat Sink Fan External Liquid Internal Liquid
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Pugh AnalysisRound 1
Computer Computer Auto Auto Computer Auto ComputerParity CRCs EECs EECs CRCs Parity CRC'sARQs FECs Hybrid ARQs Hybrid FECs ARQs
Lossless Lossy Lossy Lossless Lossy Lossy LosslessTriple DES AES XOR Triple DES AES XOR Triple DESCSMA/CA Aloha CDMA Custom CSMA/CA Aloha CDMA
Phase AM FM QAM Phase AM FMInternal Weight External Weight External Weight Internal Weight Internal Weight Internal Weight External Weight
Oring Glue M-on-M Oring Glue Oring GlueMaterial Plastic Coating Galvanization Galvanize Coating Material
Case Design Presurized Presurized Case Design Case Design Presurized Case DesignHeat Sink Fan Internal Liquid External Liquid Heat Sink Fan Fan
Power Use Datum - - - = - =Communication Error Rate Datum = - = + - =
Ease of implementation Datum = - + = + =User friendly Datum - = + - + -
Cost Datum + - - = - +Probability of Catastrophic Failure Datum - - = - = -
Effi ciency Datum - = = + - ++'s 1 0 2 2 2 2-'s 4 5 2 2 4 2
Round 2 DatumComputer Computer Auto Auto Computer Auto Computer
Parity CRCs EECs EECs CRCs Parity CRC'sARQs FECs Hybrid ARQs Hybrid FECs ARQs
Lossless Lossy Lossy Lossless Lossy Lossy LosslessTriple DES AES XOR Triple DES AES XOR Triple DESCSMA/CA Aloha CDMA Custom CSMA/CA Aloha CDMA
Phase AM FM QAM Phase AM FMInternal Weight External Weight External Weight Internal Weight Internal Weight Internal Weight External Weight
Oring Glue M-on-M Oring Glue Oring GlueMaterial Plastic Coating Galvanization Galvanize Coating Material
Case Design Presurized Presurized Case Design Case Design Presurized Case DesignHeat Sink Fan Internal Liquid External Liquid Heat Sink Fan Fan
Power Use = - = - Datum - =Communication Error Rate - - = = Datum - =
Ease of implementation = + - - Datum + =User friendly + = - + Datum + =
Cost = + - - Datum - +Probability of Catastrophic Failure + - - + Datum + =
Effi ciency - - - - Datum - ++'s 2 2 0 2 3 2-'s 2 4 5 4 4 0
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Finalized Pugh AnalysisGeneration of hybrid between two best systems
System 1 System 2 Hybrid SystemData Input Computer Computer Computer
Error Detection Parity CRC's CRC'sError Correction ARQs ARQs ARQs
(De)Compression Lossless Lossless Lossless(De)Encryption Triple DES Triple DES Triple DES
Comm. Protocol CSMA/CA CDMA CSMA/CA(De)Modulation Phase FM Phase
Sinks Underwater Internal Weight External Weight Internal WeightWater Resistant Oring Glue Oring
Corrosion Resistant Material Material MaterialPressure Resistant Case Design Case Design Case Design
Dissipate Heat Heat Sink Fan Heat Sink
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Final System SelectionData Input Computer
Error Detection CRC'sError Correction ARQs
(De)Compression Lossless(De)Encryption Triple DES
Comm. Protocol CSMA/CA(De)Modulation Phase
Sinks Underwater Internal WeightWater Resistant Oring
Corrosion Resistant MaterialPressure Resistant Case Design
Dissipate Heat Heat Sink
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Risk Analysis
Major Concerns: Speaker, Data Loss, and Carrier Frequency Loss
Minor Concerns: Power Surge, Short Circuiting, Watertight Case, and Bad Parts
ID Problem Likelyhood Damage Importance Mitigation Owners1 The housing isn't watertight 2 3 6 Test waterproofing and test the empty housing SH, GD2 Short circuit 1 3 3 CJ, CM3 Damage due to mis-handling parts 1 2 2 Team must be c areful with components All4 Loss of carrier frequency 2 3 6 Have a robust communication scheme in place CJ, CM5 Power loss 1 1 1 CM6 Power Surge 1 3 3 Surge Protection CM7 Data loss 2 3 6 Have tested error correction/detection JH8 Overheat microprocessor 1 3 3 Use effi cient code and have thermal management JH, GD9 Corrosion breach 1 3 3 Galvanize or use corrosion resistant materials SH, GD
10 Speaker doesn't work 3 3 9 Invest heavily in research & design to ensure working part CJ, CM11 Ordered components do not match specs 2 3 6 Order from reputable sources with return policies GD
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Test PlansASTM B117-11 Salt Spray Test
IPX7 Submersion Testing
Operating Temperature Testing
Error Correction Testing
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Subsystem Design Schedule
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Questions?