Hello Bharathi,

              I appreciate your interest towards working as Communication Engineer and i will help you regarding your query !!

      Yes, you can apply for the job of a Communication Engineer eventhough you don't have any additional certifications. But, you should have the minimum and at least certificate such as Bachelor's in Technology or Bachelors in engineering hailing from branches such as Electronics and communication engineering, Computer science and engineering, etc.., It will be better if you have some extra certificates such as internships, coachings, etc.., 

Hope this helps !!

All the very best wishes for your future endeavours!!