This week marks the beginning of a key event for Canada's telecom industry as up to 23 bidders compete for federal licences used in 5G wireless networks.

But a major player will be absent from this auction, as Freedom Mobile sits on the sidelines while its rivals bid for 3,500 megahertz licences starting on Tuesday.

Freedom is Canada's fourth-largest wireless carrier, and competes with Rogers, Bell and Telus in Ontario, Alberta and British Columbia.

Shaw, which has accepted a takeover offer from Rogers, will not participate in the auction.

The Rogers-Shaw deal still needs regulator approval and likely won't close until 2022 but Freedom's absence from this auction will likely weaken its ability to compete against the Big Three carriers.

The 3,500 megahertz spectrum works well in dense urban areas and spacious rural markets, which makes it a sweet spot for 5G networks.