Reconfigurable Underwater Modem for Adaptive Acoustic Switching
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Solution Overview
Problem
Commercially available underwater acoustic modems are large in size, expensive, and lack programmability, hindering their use in small-scale deployments and research applications, particularly for fleets of autonomous underwater vehicles.
Innovation Solution
A reconfigurable acoustic-based modem that supports software-controlled modulation adaptation between Binary Frequency Shift Keying (B-FSK) and Fast Frequency Hopping Frequency Shift Keying (FH-FSK) in real-time, enabling efficient data transmission and reception with a peak data rate of 2000 bps and operational range up to 50 m, using a field reconfigurable gate array (FPGA) for rapid protocol switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercially available underwater acoustic modems are used, then communication reliability is ensured, but device size becomes large and cost becomes prohibitively expensive
Solution Approach 1:
The patent implements a software-defined modem architecture that copies and emulates commercial modem functionality through open-source implementation on reconfigurable hardware (FPGA), achieving comparable communication reliability while dramatically reducing device size and cost for AUV deployments
Solution Approach 2:
The modem uses reconfigurable parameters including adjustable data rates (100-1000 bps), multiple modulation schemes (MPSK, FSK), and error correction coding that can be dynamically changed to match communication requirements, maintaining reliability across varying operational conditions while keeping the device compact
2Reliability
If commercially available underwater acoustic modems are used, then communication performance is ensured, but cost becomes prohibitively expensive for large-scale deployments
Solution Approach 1:
The patent employs low-cost FPGA-based modem implementations that can be manufactured at fractions of commercial modem costs, enabling deployment of large fleets of AUVs where individual unit cost matters more than long-term durability of each specific modem
Solution Approach 2:
The software-defined architecture provides universal communication capabilities supporting multiple modulation schemes and data rates, allowing a single modem design to serve various communication needs across different AUV models and deployment scenarios, reducing overall system cost
3Device complexity
If fixed modulation schemes are used, then device complexity is reduced, but adaptability to varying underwater environments is limited
Solution Approach 1:
The patent implements dynamic modulation adaptation where the modem can switch between different modulation schemes (BPSK, QPSK, 8-PSK, FSK) and data rates based on real-time channel conditions detected through signal quality metrics, maintaining simple operation while achieving high environmental adaptability
Solution Approach 2:
The modem incorporates feedback mechanisms that monitor communication channel quality and automatically adjust modulation parameters accordingly, allowing the system to maintain optimal performance across varying underwater environments without increasing operational complexity for the user
4Productivity
If high data rates are achieved, then communication efficiency is improved, but power consumption increases beyond acceptable limits for small AUVs
Solution Approach 1:
The patent implements variable data rate operation (100-1000 bps) with corresponding power management that allows the modem to select appropriate transmission power and modulation complexity based on mission requirements, achieving high data rates when needed while conserving power during low-bandwidth operations
Solution Approach 2:
The modem uses partial action by transmitting only essential data at high rates when channel conditions permit, while using lower data rates for routine communications, optimizing the balance between productivity and power consumption based on actual communication needs rather than always operating at maximum capacity
Data Source
AI summary
Low size, weight, power and cost (SWaP-C), flexible programmability and rapid run-time reconfigurability are desired features for the design of adaptive, underwater wireless communication modems for micro autonomous underwater vehicle (μAUV) swarms. Disclosed herein are first-generation and second-generation software and hardware design of a new class of low SWaP-C underwater modems that can accommodate wide-band acoustic front-ends and achieve s-level reconfigurability during run-time. By dynamically mapping certain signal processing operations of the acoustic communication stack to the Field Programmable Gate Array (FPGA) and others to the embedded processing system of the modem's System-on-Chip, data rates of up to 2000 bps can be achieved in ranges up to 50 m with the implementation of custom programmable logic.