The new next Samsung Galaxy is being “unpacked” on 21st February 2016, which is officially notified by Samsung. The event starts at 19:00 CET (21:30 IST). If you are there at Barcelona and planning to attend this event then the doors are opened at 18:00 CET. The event is held at CCIB (Centre de Convencions Internacional de Barcelona). Barcelona is the city where the next MWX (Mobile World Congress) is going to held
Samsung has not officially declared what is the next Galaxy that is going to be unveiled but as per the rumors rounding on the internet sources probably the Galaxy S7 and Galaxy S7 Edge is going to be unveiled. Earlier we had seen the Galaxy S7 and Galaxy S7 press release images leaked on internet:

Samsung has also unveiled a teaser video for the next Galaxy launch, checkout here:
https://www.youtube.com/watch?v=3g3O94WALV8
You can watch the live streaming of Samsung Galaxy on Feb 21. Also you can get the event updates directly from Samsung NEWS room.