There are plenty of options for your accommodation in Vienna: Hotels, BnBs, Room Rentals and Youth Hostels will be happy to accomodate you.

See the tourist information website for hotels in Vienna:
https://www.wien.info/en/travel-info/hotels-accomodations

Hotels close to the conference venue:

• Motel One Wien-Prater (3 Stars)
  https://www.motel-one.com/de/hotels/wien/hotel-wien-prater/
   

• Superbude (4 Stars)
  www.superbude.com
   

• Hilton Vienna Messe Prater (4 Stars)

If you search for accomodations in the area of the "Wiener Prater" the hotels you will find will be fairly close to the conference venue.

Other accommodation options than the ones listed above, such as those in the inner city, can be a great alternative if you want to be located closer to the historic center of Vienna. Staying in a hotel within the inner city offers the charm of Vienna’s cultural landmarks with a commute of around 20 minutes via Vienna's well-maintained public-transport-network to the conference venue.

Digital Map with indicators for the most important places for the conference:

Link Digital Conference-Map