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I am an electrical engineering undergrad with an interest in communication theory, networks, signal processing and optimization. I have PhD offers from two groups - one working in communications & networks and another working in statistical signal processing, compressive sensing & community detection. How do I decide between the two? It is my opinion that currently communication theory and networks have become a mature field with not much scope for rapid growth or fundamental path-breaking research, while the work in the other group is quite more "in vogue" due to machine learning based applications and has the potential to solve more fundamental problems.
A comparison between the two areas with regards to future research and job opportunities would be great.