Chris Monfredo Chris Johnson Jon Holton Greg Davis Scott Hambleton 10/03/13Rochester Institute of Technology1 P14251 Underwater Acoustic Communication

10/03/13Rochester Institute of Technology2 Agenda  Revisit Customer and Engineering Requirements  Functional Decomposition  Morphological Charts  Morph Details  Pugh Analysis  Final Pugh Analysis  Final System Selection  Risk Analysis  Test Plans  Subsystem Design Schedule

10/03/13 Rochester Institute of Technology 3 Underwater Acoustic Communication Customer Requirements  Most important requirements:

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology4 Engineering Requirements  Most important requirements:

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology5 Functional Decomposition

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology6 System Flow Diagram

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology7 Communication Protocols: ALOHA Easy to Implement Inefficient – Theoretical throughput of 18% (36% for slotted ALOHA) Better suited for long distances

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology8 Communication Protocols: CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) Less Noise Better Throughput Can function with swarm expansions Terminal Problems vs. Overhead

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology9 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

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology10 Error Detection and Correction Detection Methods:  Parity Bits  Cyclic Redundancy Checks (CRCs)  Error Correcting Code (EEC) Correction Methods:  Automatic Repeat Requests (ARQs)  Forward Error Correction (FEC)  Hybrid Schemes (Both ARQ and FEC)

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology11 Encryption and Compression Encryption Methods:  Triple DES (56-bit)  AES (128-bit)  If not enough time, something simple (XOR the bit stream) Compression Methods:  Lossless Algorithms  Lossy Algorithms

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology12 Computational Power Microprocessors:  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.

Underwater Acoustic Communication Rochester Institute of Technology13 Power Converters  Transformer  High voltage step-down or positive and negative voltage  Buck Converter  High efficiency step-down  Linear Regulator  Easy to implement but low efficiency 10/03/13

Underwater Acoustic Communication Rochester Institute of Technology14 Amplitude Modulation  Easy to Implement  Requires more power than other schemes  Carrier frequency must be about 10X data rate 10/03/13

Underwater Acoustic Communication Rochester Institute of Technology15 Frequency Modulation  Susceptible to frequency shifts due to Doppler effect or sound speed changes  Carrier frequency is move flexible than AM 10/03/13

Phase Shift Keying  Harder to implement than FM but more resistant to noise  More bandwidth efficient than FM Underwater Acoustic Communication Rochester Institute of Technology1610/03/13

Underwater Acoustic Communication Rochester Institute of Technology17 Quadrature Amplitude Modulation  Hardest to implement  Can encode the most amount of information  Susceptible to noise 10/03/13

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology18 Corrosion Resistant  Material Selection  Metals  Plastics  Corrosion Resistant Coating  Barrier  Galvanization Water Resistance  Gasket/O-rings  Caulk/Sealant  Tight Fit Pressure Resistance  Structural Strength/Case Design  Internal Pressurization

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology19 Dissipate Heat  Heat sink  Fan  Liquid cooling  Use external water  Use internal system Image from:

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology20 Morphological Chart

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology21 Pugh Analysis

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology22 Finalized Pugh Analysis  Generation of hybrid between two best systems

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology23 Final System Selection

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology24 Risk Analysis Major Concerns: Speaker, Data Loss, and Carrier Frequency Loss Minor Concerns: Power Surge, Short Circuiting, Watertight Case, and Bad Parts

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology25 Test Plans  ASTM B Salt Spray Test  IPX7 Submersion Testing  Operating Temperature Testing  Error Correction Testing

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology26 Subsystem Design Schedule

Underwater Acoustic Communication 10/03/13Rochester Institute of Technology27 Questions?