Hi Tarek,
As you are fresher, no need to go in-depth of Telecom technologies. Prepare the topics whatever you have mentioned in your CV, your final year project and training you have received as a part of your educational curriculum. Besides, prepare basic telecommunications technologies (definition and principle of Basic Telephony, GSM/CDMA/UMTS), simple and basic call flows, network nodes etc.
Wishing all the best and good luck for your interview.
Thanks
Shri