It means the sale cannot be reversed unless the Canadian government cites security concerns, or if it concludes that Nortel grossly undervalued the assets.

Tuesday was the last date for BlackBerry maker and opposition parties to file for a court review of the asset sale, but they didn't challenge the deal in court.

So the ball is now the government's court.

Wireless technology experts say both of Nortel's wireless business technologies - CDMA and the next-generation technology called LTE - were developed in collaboration with many other companies.

They argue that this makes it hard for RIM and opposition parties to argue that the sale of these technologies carry national security interests, a newspaper quoted experts as saying.

Further, Mark Henderson, CEO of Ericsson Canada, has clarified to the Canadian parliamentary committee that his company is only buying wireless technology while Nortel will continue to own the patents.

He says Ericsson has been operating in Canada for decades and has invested millions in innovation here.