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FlexLink, a Practical OFDM Datalink, Introduction and Python Demonstrations
Leonard Dieguez - Watch Now - DSP Online Conference 2024 - Duration: 55:23
This presentation can be described as a technical deep-dive into the design and implementation of the FlexLink waveform, specifically tailored for drone communication systems. It covers both theoretical and practical aspects, providing an in-depth look into the key elements of the waveform, such as the Burst, Preamble A, Preamble B, first control signal with references, and Payload A.
In addition to the technical breakdown, the presentation includes a live demonstration of how Python-based model design code runs, showcasing the practical implementation of the waveform. The focus is on how this waveform optimizes communication in high-mobility environments, specifically on drones, and how its features support real-time video transmission, telemetry, and control.
Description of the Presentation:
- Content Focus: Detailed exploration of FlexLink waveform elements and how they apply to the waveform and drone communications.
- Hands-On Demonstration: Demonstrating Python code for model-based design, bridging theory and practical implementation.
- Target Audience: Engineers, designers, and technologists interested in RF waveforms, drone communication systems, and model-based design.
- Outcome: Attendees will gain an understanding of how FlexLink is implemented in real-world UAV applications, including insights into the signal structure, operational advantages, and how to use Python for performance modeling.
This presentation serves as both an overview and demonstration that blends knowledge with practical coding and design applications.
Thanks. Over the last year I have been investigating ways to create a UAV data link and have done some experiments on the 40.68MHz ISM band using a crude protocol using 4FSK (going for distance on the lower VHF), but the multipath is very to difficult to overcome, so was investigating using a slow data rate OFDM. Even thinking to just move to 915MHZ ISM. Thanks for this and I will look more into flexlink, but not sure I need 6MHz channel. Wanted to avoid the FPGA route and do the DSP on some simpler parts.
Also is Andreas' 3rd edition book already available? I have thoroughly worn out his first edition and want to thank him for his excellent and practical explanations.
He should be in the live Q&A session on the 30th. There are probably some interesting things you can do if the data rate is slow. One thought would be replicate the data or "spread" the data across multiple ofdm symbols and bins. This could allow you to lower the overall signal power output as well. This is meant to be a framework starting point for people that wish to design custom datalinks. We are still refining the "spec" and working on receiver sections. Overall someone could tailor the datalink to operate in lower bands and use less data or bandwidth.
Thank you for the presentation. I am curious as to how much frequency and sampling rate error in ppm can be supported by this preamble design. 20 years ago, I remember having to do coarse then fine frequency offset acquisition followed by phase tracking. It is not obvious that coarse and fine acquisition are both possible in this air interface and the sub carrier spacing is pretty narrow, so I was wondering how this is achieved. Thank you.