IP Law Daily, PATENT—Fed. Cir.: Apple loses key challenges to Smart Mobile wireless patents, (Aug 28, 2026)

By George Basharis, J.D.

A narrow reading of “multiplexed signals” preserved numerous Smart Mobile patent claims against Apple’s obviousness challenges, while other findings were vacated because the PTAB failed to address evidence that Apple’s prior-art combination would create a data bottleneck.

Apple failed to invalidate numerous Smart Mobile Technologies wireless-device patent claims because its proposed prior art did not disclose the required multiplexing of signals, while Smart Mobile revived separate claims after the Patent Trial and Appeal Board failed to address evidence that Apple’s proposed combination would impair data transmission. In two related decisions, the U.S. Court of Appeals for the Federal Circuit upheld a construction requiring multiple signal streams to be combined into one, rejecting Apple’s broader interpretation that would encompass signals transmitted sequentially over the same path. It also vacated obviousness findings covering other claims because the Board overlooked Smart Mobile’s evidence that combining the cited technologies would create an undesirable data bottleneck (Apple Inc. v. Smart Mobile Technologies LLC, No. 25-1090 (Fed. Cir. Aug. 27, 2026)) and Apple Inc. v. Smart Mobile Technologies LLC, No. 24-1607 (Fed. Cir. Aug. 27, 2026)).

Smart Mobile owns a family of patents directed to mobile wireless devices that use multiple transmitters, receivers, antennas, networks, and communication paths. The patents claim priority to a 1999 application and share a common specification. Smart Mobile sued Apple for infringing 13 patents, prompting Apple to seek inter partes review of several of them. The infringement litigation was transferred from Texas to the Central District of California, where it remains stayed pending the inter partes reviews.

Three patents from that family were at issue in the related appeals: U.S. Patent Nos. 8,842,653, 9,019,946, and 9,319,075. The ’653 and ’946 patents describe mobile devices with multiple transmit-and-receive components, while the ’075 patent covers an IP-enabled communication device using multiple wireless communication units and network paths.

Multiplexed signals. Apple’s challenge to many claims of the ’653 and ’946 patents turned on the meaning of “multiplexed signals.” The disputed claims require multiple IP-enabled interfaces to create a single transmission interface composed of multiplexed signals from multiple wireless transmit-and-receive components.

Apple advocated a broad interpretation. It maintained that multiplexing encompasses multiple inputs sharing a single physical resource even when the signals are not combined before transmission. That construction would include “switching,” in which different signals travel sequentially over the same path. Smart Mobile maintained that multiplexing instead requires combining separate signals into a composite signal before simultaneously transmitting them along a shared physical pathway. The Board implicitly adopted Smart Mobile’s narrower interpretation.

The Federal Circuit agreed. The claim language refers to “multiplexed signals,” indicating that the signals themselves, rather than merely their paths, must be multiplexed. Apple’s interpretation could treat two signals traveling over the same path seconds, minutes, or even years apart as multiplexed, a reading the claim language did not support.

The shared specification reinforced that conclusion. It describes multiplexing as a function performed on signals at either end of a shared path. The pathway serves as the medium over which multiplexed signals travel, but using a shared pathway does not itself constitute multiplexing. Other portions cited by Apple addressed a device’s ability to communicate with different networks sequentially or simultaneously without showing that the signals themselves were multiplexed. As a result, the Federal Circuit construed “multiplexed signals” to mean “combining multiple signal streams into one,” excluding multiple signals that merely use the same path sequentially.

Prior art falls short. That construction undermined Apple’s reliance on two prior-art references, Yegoshin and Bernard. Yegoshin describes a cellular phone capable of communicating over cellular and wireless local area networks, while Bernard describes an external cradle that allows a personal digital assistant to communicate with multiple networks. Apple argued that the references, alone or together, disclosed the claimed multiplexing.

However, substantial evidence supported the Board’s contrary findings. Yegoshin directed a user to select a network for communication and did not establish that the phone simultaneously received cellular and WLAN calls in a manner requiring multiplexed signals. Bernard expressly described a multiplexer only in an embodiment different from the one Apple relied upon. The relevant embodiment instead described establishing one of four connections at a time. Although Bernard contemplated an alternative interconnection permitting simultaneous connections, Apple failed to identify that interconnection or explain how it could be incorporated into the proposed combination.

Apple fared no better in challenging the related ’075 patent. There, the Board expressly construed “multiplexing signals” as combining multiple signal streams into one and found that Yegoshin and Bernard did not disclose the limitation. Because the evidence and arguments materially tracked those involving the ’653 and ’946 patents, the Federal Circuit adopted the same construction and upheld the Board’s findings. The ’075 patent’s express distinction between “multiplexing signals” and “multiplexed paths” further weakened Apple’s argument that combining paths was enough. The rulings ultimately preserved numerous claims of all three Smart Mobile patents against Apple’s obviousness challenges.

Bottleneck evidence. Smart Mobile obtained a different result on other claims the Board had found obvious. Unlike the claims discussed above, these claims do not require “multiplexed signals.” Instead, they require a processor configured to combine data paths into a single transmission interface to applications on the mobile device.

Apple proposed combining Yegoshin’s phone with functionality from Bernard’s external cradle. It maintained that a skilled artisan would have been motivated to incorporate the cradle’s multi-network functionality into the phone to gain connectivity to multiple networks without requiring external hardware.

Smart Mobile responded that Bernard’s serial interface would significantly reduce transmission speed and create an undesirable bottleneck, giving a skilled artisan reason not to make the combination. Its expert explained that the serial interface transmitted data one bit at a time and operated more slowly than other available interfaces and Yegoshin’s existing system.

The Board nevertheless stated that neither Smart Mobile nor its expert had addressed Apple’s rationale for combining the references. The record showed otherwise. Smart Mobile’s bottleneck evidence directly responded to Apple’s proposed combination, leaving the Federal Circuit unable to determine whether the Board had considered evidence that could weigh against its asserted benefits. Consequently, the Federal Circuit vacated the obviousness findings on those claims and returned them to the Board. On remand, the Board must consider the benefits and drawbacks of Apple’s proposed combination, including the transmission bottleneck identified by Smart Mobile.

The Case is Nos. 25-1090 and 24-1607.

Judge: Stark, L.

Attorneys: Debra Janece McComas (Haynes and Boone, LLP) for Apple Inc. Philip Graves (Graves & Shaw LLP) for Smart Mobile Technologies LLC.

Companies: Apple Inc.; Smart Mobile Technologies LLC

Cases: Patent FedCirNews TechnologyInternet GCNNews