AT&T, Verizon Defeat East Texas Cell Patent Infringement Suit

AT&T Corp. and Verizon Wireless fended off a patent suit after convincing a federal judge that the patent’s owner improperly sought to expand its scope for its infringement case.

Howlink Global LLC sued the cellular carriers in February 2022, alleging they infringed four cellular communications patents. The case was eventually narrowed to one asserted patent—US Patent No. 8,630,279, which US District Court for the Eastern District of Texas Judge J. Rodney Gilstrap ruled Wednesday wasn’t infringed by the companies.

Gilstrap adopted a ruling from Magistrate Judge Roy Payne that determined Howlink’s infringement theory relied on an improperly broad reading of the ‘279 patent’s scope. That interpretation wasnt permitted given concessions made to the US Patent and Trademark Office when the South Korea-based Electronics and Telecommunications Research Institute was seeking the patent’s approval.

Howlink asserted that its patent was infringed solely under the doctrine of equivalents, according to Payne, meaning that AT&T and Verizon weren’t accused of literal copying Howlink’s patent through the creation of their cellular network systems. Rather, the companies were accused of infringing the patent under a theory that relied on a broad definition of the term “concatenation,” a concept that relates to the way mobile devices read identification codes.

However, Payne wrote, “prosecution history estoppel precludes Howlink’s reliance” on that theory.

Payne said during ETRI’s application process for the ‘279 it’s application was initially rejected as obvious in light of a patent issued to Telefonaktiebolaget LM Ericsson in 1999. The applicant later modified its application to specifically surrender the broader definition of “concatenation” that Howlink was now claiming in the lawsuit, Payne said.

LTL Attorneys LLP; Eichmann PC; and Capshaw DeRieux represent Howlink.

The cell carriers are represented by Alston & Bird LLP and Dacus Firm PC.

The case is Howlink Global LLC v. AT&T Inc., E.D. Tex., 2:22-cv-40, summary judgment granted 6/21/23.