Arqiva, the communications infrastructure company that also owns VoD platform SeeSaw, is the seventh partner to join after the BBC, BT, Channel 4, Five, ITV and TalkTalk.
The partners will take equal stakes, each providing the same amount of funding to the venture.
Project director Richard Halton said: "Arqiva have a history of positive and progressive support for Freeview, and Project Canvas will benefit hugely from both their experience and engineering expertise."
The news comes as it emerged the Office of Fair Trading is to open an investigation into Project Canvas.
