AT&T secures 4G LTE patent suit win before Fed Circuit
The US Court of Appeals for the Federal Circuit has affirmed a Texas court’s claim construction in a case involving telecoms companies AT&T and Ericsson.
In a precedential decision, handed down yesterday, August 12, the Federal Circuit concluded that the district court had correctly defined a term in Iridescent Networks patent, US number 8,036,119, which led to a finding of non-infringement by the telecoms companies.
Iridescent Networks is the assignee of the ‘119 patent, which is directed to a system and method of “network communication that provides guaranteed bandwidth on demand for applications that require high bandwidth and minimises data delay and loss during transmission”.
Back in July 2016, Iridescent accused AT&T and Ericsson of infringing its patent in a suit filed at the US District Court for the Eastern District of Texas. Iridescent claimed that its patented technology covers critical features of AT&T’s 4G LTE network.
During claim construction proceedings, Iridescent proposed broadly construing the term “high quality of service connection” in claim 1 of the patent to mean “a connection in which one or more quality of service connection parameters, including bandwidth, latency, and/or packet loss, are assured from end-to-end based on the requirements of the application”.
However, a magistrate judge decided to largely adopt AT&T’s proposed construction.
The judge considered the term to mean “a connection that assures connection speed of at least approximately one megabit per second and, where applicable based on the type of application, packet loss requirements that are about 10-5 and latency requirements that are less than one second”.
Iridescent objected to the construction, but the district judge overruled the objections.
The parties agreed that under the district court’s construction, AT&T’s accused network products and services were excluded, and they jointly stipulated to non-infringement.
Background to the case
In December 2017, the Texas court entered a final judgment against Iridescent, which the company subsequently appealed against.
Circuit Judge Jimmie Reyna, on behalf of the Federal Circuit, said: “This appeal turns on whether the term “high quality of service connection” is a term of degree that is limited to the minimum connection parameter requirements disclosed in figure 3 of the ‘119 patent. We conclude that it is.”
First, the court noted that the claim language is silent as to what amount of quality is sufficient to be high. Because of this, the Federal Circuit then looked first to the specification, followed by the prosecution history, to determine the meaning.
According to Reyna, Iridescent had relied on the minimum connection parameter requirements described in figure 3 to overcome an examiner’s section 112 enablement rejection.
While Iridescent argued that the prosecution history was irrelevant to the claim construction question because there was no “clear and unmistakable disavowal of claim scope”, the court disagreed.
“In these circumstances, where there is no clear ordinary and customary meaning of a coined term of degree, we may look to the prosecution history for guidance without having to first find a clear and unmistakable disavowal,” said Reyna.
According to the Federal Circuit, the district court was correct to look to the specification and the prosecution history for disclosure of what constitutes high quality of service, and that its subsequent analysis was correct.
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