Satellite TV operator Dish Network has raised its bid for Clearwire Corp., valuing the wireless network operator at $6.9 billion, in an attempt to outbid Sprint Nextel Corp. two days before Clearwire shareholders are meeting to vote on a deal.

Dish's bid of $4.40 in cash per share is 29 percent higher than Sprint's bid of $3.40 per share. Sprint wants to buy the half of Clearwire that it doesn't already own.

Dish's previous offer, from January, was for $3.30 per share.

Dish Network Corp. chairman Charlie Ergen said in a statement that Clearwire's —space on the airwaves—is key to Dish being able to deliver future services.

Dish has also offered to buy Sprint.

Clearwire shares are up 22 percent to $4.23 in after-hours trading.

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