Dish Network on Wednesday urged the Federal Communications Commission to reject Comcast's $45.2 billion bid to buy rival player Time Warner Cable on competition grounds.

In a letter to the FCC following a series of meetings, the U.S. satellite TV company also expressed concern about the impact of AT&T's planned $48.5 billion takeover of DirecTV, and confirmed that it will bid in the country's upcoming AWS-3 and 600-MHz spectrum auctions.

"The pending Comcast/Time Warner Cable (TWC) merger presents serious competitive concerns for the broadband and video marketplaces and therefore should be denied," Dish said.

The firm believes the proposed cable operator tie-up poses a threat to net neutrality, claiming that the merged Comcast/TWC could use its "control over the broadband pipe" to undermine over-the-top (OTT) services and squeeze out its competitors' video services.

Dish also expressed concerned that the company would be able to manipulate the content space due to "its enormous size". Specifically, the satellite firm is concerned that Comcast/TWC would be able to force programmers to provide content at lower rates, which would lead to them recouping the lost revenue by demanding higher rates from smaller pay TV providers like Dish. It also believes the merged entity would be able to prevent rival companies from acquiring content rights.

It has similar concerns regarding AT&T's DirecTV takeover. Those companies could use their combined strength to control content "to the potential detriment of consumers," Dish said.

Regarding the upcoming spectrum auctions, Dish said "it looks forward to meaningfully participating" in next year's 600-MHz incentive auction, in which frequencies currently held by broadcasters will be reorganised and made available for the mobile industry. The FCC plans to reserve a certain amount of spectrum – to be determined based on the amount ceded by broadcasters – to players that do not already hold a substantial amount of sub-1 GHz bandwidth, a move that will restrict the participation of the country's biggest telcos.

"The incentive auction offers opportunities for competitive providers and new entrants to bid on and win much-needed low-band spectrum, which will facilitate the deployment of mobile broadband services," Dish said.

Dish also confirmed that it will take part in the AWS-3 auction scheduled to take place in mid-November.