Arriving in Canada
Since November 2016, an Electronic Travel Authorization (ETA) has been compulsory for travelling to Canada as a foreign visitor for whom a visa is not necessary. This requirement is not applicable to Americans and visitors who are in possession of a valid visa.
Consult the following pages from the Canadian government about visas and ETA:
Visa Invitation Letter
Visa letters of invitation can be issued only to attendees who have registered for the conference and have paid for their registration in full. This is an IEEE Policy, and there are no exceptions.
Once you have registered via the conference Registration site and your payment has been confirmed, you will be issued a letter of invitation automatically.
The Conference cannot contact or intervene with any Embassy or Consulate office abroad on your behalf, so please register early and begin your visa application process early.