In a move signifying that it may be bitter about a recent business deal between cable companies and a major rival, Sprint Nextel Corp. has sued Comcast Corp., Time Warner Cable Inc. and other cable giants for allegedly infringing on its patents.

Sprint, which is the third largest wireless operator in the U.S., claims Comcast, Time Warner, Cox Communications Inc. and Cable One Inc. are misappropriating digital phone technology that it patented in the 1990s. The company filed its lawsuits yesterday in federal court in Kansas City, Kan., claiming the cable companies are infringing a total of 12 of its patents.

Sprint’s suits reflect its increasingly strained relationship with cable providers, which at one time were its major customers. Earlier this month, Comcast and Time Warner struck a deal with Sprint’s rival, Verizon Wireless, in which Verizon would pay $3.6 billion to acquire the cable companies’ spectrum, or airwaves that carry traffic across the cellular network. The deal also allows the cable companies to resell Verizon-branded service, and Verizon stores in turn can sell cable service.

Read Bloomberg for more information about Sprint’s lawsuits.