I applied online.I was interviewed at 5G Testbed IIT-Hyd (Hyderābād). The process took some time, but the end was fruitful.
Round 1 : Aptitude and coding round.
Basics questions related to aptitude which was easy to medium.
Coding was also simple.
Round 2 : asked based on resume, basics in Digital Signal Processing, Wireless Communication fundamentals, projects mentioned.
Round 3: basics in C, arrays and pointers
Round 4: Hr round, asked about difficulties faced during projects and how you overcame. What is your current goal. etc.