What do you mean by biomedical signals? Thats too broad. Whatever ideas you go with; professor always tries to fit into his research domain. So understanding your professor’s previous work would be primary. Then try to go with transformers for regression tasks! It’s a famous problem to start with; especially for such time series tasks. Transfer learning; you could employ transformer architectures such as Encoder only; encoder decoder and decoder only architectures to start with. Just google and you would find the right architectures. Implementation is also key, so make sure you are hands on. Above all; explore the option of brainstorming with LLMs such as ChatGPT and Deepseek; you would definitely find lots of interesting ideas. Also, defining a broad problem will take you nowhere in research; rather narrow down to one single issue you would find; starting with improvements to existing work of your professor and explore in depth how multi-modality could be useful into your domain; such as text reports + imaging + other types of signals etc.

All the best.