XR Communications, LLC v. Ruckus Wireless, Inc.

Background

XR Communications, LLC, doing business as Vivato Technologies, accused Ruckus Wireless, Inc. and Arris Solutions, Inc. of infringing United States Patent No. 6,611,231. The patent concerns wireless communications systems and networks using adaptively steered antenna arrays. The parties agreed on the meaning of every patent term except “search receiver logic.”

The disputed term appears in claim 1, which describes “search receiver logic” operatively connected to the patent’s control logic, receiver, and adaptive antenna. The term is configured to update routing information based at least in part on cross-correlated signal information received by the receiver using the adaptive antenna. Related claims also describe functions involving maintaining routing information and determining transmission constraints.

Vivato argued that “search receiver logic” had a plain and ordinary meaning and did not need further construction. The defendants argued that the term was a functional substitute for “means” and therefore should be treated under 35 U.S.C. § 112(6), the patent provision governing means-plus-function limitations.

Legal standard

A means-plus-function limitation describes a function without sufficiently identifying the structure that performs it. If section 112(6) applies, the court first identifies the claimed function and then determines whether the patent specification discloses corresponding structure—meaning structure clearly linked to that function. If the specification does not disclose adequate corresponding structure, the claim is indefinite.

Because “search receiver logic” does not use the word “means,” the court began with a presumption that section 112(6) did not apply. The court explained that the presumption was rebuttable and not strong. Under the Federal Circuit’s standard, the question was whether a person of ordinary skill in the relevant field would understand the term to identify sufficiently definite structure for performing the claimed function.

Analysis

The court held that the defendants overcame the presumption. It rejected Vivato’s reliance on an older, stricter legal standard requiring a showing that the term was essentially devoid of anything that could be considered structure. The court instead applied the rule requiring sufficient structure for the particular function claimed.

The court found persuasive the defendants’ expert testimony that known uses of “search receiver” in electronic warfare and global-positioning-system technology did not identify structure capable of updating routing information in the wireless network described by the patent. The court also relied on the patent’s broad definition of “logic” as hardware, firmware, software, or combinations of those items, along with supporting circuitry. In the court’s view, that definition did not identify sufficient structure for the claimed functions.

The court also rejected Vivato’s arguments based on the surrounding claim language. The fact that “search receiver logic” was operatively connected to physical components did not, by itself, identify the structure of the disputed term. The court noted that the term was not depicted as a structural component in Figure 2 and that merely placing a limitation within a structure does not make the limitation sufficiently structural.

For the second step, the court adopted the defendants’ description of the relevant claim 1 function: updating the routing information based at least in part on cross-correlated signal information already received by the receiver using the adaptive antenna. The court also adopted the defendants’ description of claim 12’s function concerning determining a transmission constraint based at least in part on the received signal and including that constraint in the routing information.

Vivato identified the search receiver shown in Figure 18 and processes 610 and 612 in Figure 22 as corresponding structure for claim 1. The court disagreed. It found that Figure 22 described a search receiver process in which the signal was received before the cross-correlation process occurred. That did not clearly correspond to claim 1’s requirement that the information already be cross-correlated when received. The court also found that Vivato’s effort to rely only on selected portions of Figure 22 was inconsistent with the specification’s description of the entire figure as an exemplary search receiver process.

The court further found that Figure 18 did not disclose adequate corresponding structure. It described the search receiver as a black box, did not show the structure that produced the updated routing information, and did not depict the required cross-correlated-signal input. The court also rejected Vivato’s reliance on Figures 4, 5, and 15. Those figures either did not disclose the claimed updating function or did not clearly link a disclosed structure to that function. Expert testimony could not create structure that the specification itself did not adequately disclose.

Conclusion

Judge Orrick concluded that “search receiver logic” is a means-plus-function limitation and that the patent specification does not disclose adequate corresponding structure for its claimed functions. The court therefore ruled that the term was not amenable to construction and was invalid for indefiniteness under section 112(6). The opinion is classified as a substantive ruling because the court decided the patent-law issue presented in the claim-construction dispute.