Verizon Wireless announced Thursday it will buy rural mobile service provider Alltel Corporation for $28.1 billion including debt. The acquisition moves Verizon ahead of AT&T as the largest U.S. wireless firm. Under terms of the deal, Verizon Wireless would acquire the equity of Alltel for $5.9 billion, and assume an estimated $22.2 billion in debt. Verizon Wireless said the deal would generate savings of $1 billion in the second year after it closes. It forecast total savings of more than $9 billion by 2011, citing reduced capital and operating expenses. Verizon Wireless also said the deal would add to profits in the first year.