This meeting of the Open Research Institute's (ORI) FPGA projects provides updates on several key initiatives in open-source digital radio communication. The core discussion revolves around the "Opulent Voice" protocol, detailing the development of its Minimum Shift Keying (MSK) modem on an FPGA and the layered architecture for handling voice, chat, and data, with a focus on prioritizing voice for seamless human experience. Progress on the DVBS2 downlink for their satellite project is shared, alongside efforts in designing robust waveforms and Forward Error Correction (FEC) for extremely challenging two-way communications with Venus as part of the EVE project. The team emphasizes the modularity, accessibility, and architectural decisions, including the strategic use of standard internet protocols, to foster broad citizen science participation and demonstrate advanced digital communication techniques.
Summary:
0:00 ORI FPGA Meetup Introduction: The Open Research Institute (ORI) hosts a meetup to discuss progress, plans, and roadblocks for their FPGA-based open-source digital radio communication projects.
0:47 Satellite Downlink Update: Aaron (K I5BA) reported progress on integrating the DVBS2 downlink for the satellite project, including running Pluto-based ORI firmware controlled via MQTT and plans to test transmit functionality with a BATC Picot tuner receiver.
2:50 EVE Project (Venus Communications): Pete outlined efforts to design a practical FSK waveform for extremely challenging two-way communications with Venus, aiming to overcome a difficult link budget by utilizing non-coherent correlations and robust Forward Error Correction (FEC) codes for the next Venus conjunction in October 2026.
10:11 Opulent Voice Protocol & Modem: Michelle and Paul provided a detailed overview of the "Opulent Voice" project, highlighting the FPGA-based Minimum Shift Keying (MSK) modem (developed by Matthew Wishik) which is designed for spectrally efficient and constant-envelope communications suitable for both amateur satellite and terrestrial use.
13:25 Priority Data Handling & UX: The team demonstrated a Raspberry Pi 4-based system that frames and prioritizes different data types (voice, chat, file). They decided to re-prioritize voice as the highest priority to prevent interruptions from authentication/authorization messages, ensuring a better user experience.
17:40 Authentication & Security: Each transmission frame includes a claimed identity and a cryptographically calculated token. The receiving station (e.g., satellite) can enforce customizable authentication policies, allowing flexibility for operators to decide how strictly to control access.
26:35 Protocol Layering & COBS: The protocol uses a combination of custom "Opulent Voice" headers and standard internet protocols (IP, UDP, RTP, TCP). Constant Overhead Byte Stuffing (COBS) is employed as the encasing protocol for efficient and flexible frame delineation.
30:22 Forward Error Correction (FEC) Plans: While the current wired prototype omits FEC, it is a crucial component for over-the-air reliability. The team is evaluating whether the Raspberry Pi or the FPGA modem should handle Golay encoding for headers and Viterbi encoding for the payload.
34:19 Voice Quality & Bit Rate: The system utilizes the Opus voice codec at 16 kilobits/second in a Constant Bit Rate (CBR) mode, delivering excellent voice quality. Future optimizations may include Variable Bit Rate (VBR) to potentially insert chat data during periods of silence.
43:57 System Modularity & Accessibility: The "Opulent Voice" system is designed with three modular components (web interface, Raspberry Pi 4 for framing, and remote radio/modem) that can be integrated or separated. This modularity, combined with a low barrier to entry (Raspberry Pi 4, Python scripts), aims to encourage widespread testing and citizen science participation.
46:56 Rationale for Standard Protocols: The decision to incorporate standard protocols (IP, UDP, RTP, TCP) is justified by their proven reliability, compatibility with existing application-layer programs, and the flexibility they provide, outweighing the minor overhead.
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