Verizon, T-Mobile Accused of Infringing ‘VoWi-Fi’ Calling Patent

T-Mobile US Inc. and Cellco Partnership, which operates as Verizon Wireless, lacked permission when they incorporated into their mobile telecommunications networks protected technology that lets customers seamlessly switch from cellular service to Wi-Fi without dropping calls, according to a Texas lawsuit.

Aspen Networks Inc., a California tech firm, accused the two telecom giants of violating US Patent No. 8,009,554, which was granted in 2011, according to complaints filed Dec. 1 in the US District Court for the Eastern District of Texas.

Aspen said its technology lets callers “make and receive calls in locations with poor or no access to ...