Mountain Cablevision was owned by Shaw Communications but has been purchased by Rogers.

Rogers Communications, already Canada’s largest mobile-phone company, will grow even larger with the acquisition of Shaw Communications’ unused wireless spectrum and a Shaw-owned cable company making inroads in Rogers’ backyard in southwestern Ontario.

Rogers has agreed to pay $300 million for the spectrum and $400 million for Hamilton, Ont.-based Mountain Cablevision, Ltd. In return, Shaw will acquire a one-third interest in Rogers’ TVtropolis network.

Shaw is getting a premium price for the wireless spectrum it acquired in 2008 for $190 million. Shaw, like many American cable companies, originally planned to launch competing mobile phone service but aborted the effort in 2011, deciding to invest in its broadband service and construct a Wi-Fi network in western Canada instead.

Rogers CEO Nadir Mohamed told Bloomberg News the spectrum is needed to meet growing demands from Canadian wireless broadband customers.

“The wireless business is defined by what I would describe as an explosion in terms of usage,” Mohamed said. The new spectrum “will help us meet that demand in terms of capacity and speed.”

Rogers is by no means finished acquiring spectrum. The company plans to borrow as much as $800 million to purchase more at the next Canadian spectrum auction later this year.