G+ Communications v. Samsung — Federal Circuit Upholds Invalidity of 5G Patent Claims

Background

G+ Communications owns U.S. Patent No. 10,736,130, covering techniques for transmitting uplink control signals in faster cellular systems. The challenged claims require predefined signal sequences of length N to be mapped to N subcarriers. Samsung petitioned for inter partes review, arguing that an earlier patent known as Kwak disclosed every limitation.

The Patent Trial and Appeal Board agreed and found claims 1–5, 7–9, 14, and 20 anticipated. G+ focused its appeal on figures in Kwak that it said necessarily used a “comb structure.” In that arrangement, every other subcarrier would be reserved for a reference signal, supposedly leaving too few subcarriers to satisfy the claimed one-to-one mapping.

The Court’s Holding

The Federal Circuit affirmed. Judge Prost first rejected G+’s argument that the Board violated the Administrative Procedure Act by relying on a new theory first raised at oral argument. G+ itself had introduced the comb-structure issue, the disputed “may” language appeared in Kwak, and Samsung’s oral-hearing explanation was consistent with its position throughout the review. Parties may elaborate on arguments already in the case, and the Board used the point as only one part of a broader analysis.

Substantial evidence also supported the Board’s technical findings. Kwak said its figure “may” use a particular structure, which did not make that structure mandatory in every embodiment. A prior-art reference can anticipate a claim when at least one disclosed mode of operation contains all limitations, even if other modes do not. The Board also credited Samsung’s expert, who explained that the relevant figure lacked shading used elsewhere to denote regions associated with a comb structure.

Because Kwak disclosed an embodiment mapping the required sequence to the claimed number of subcarriers, the Board reasonably found the challenged claims anticipated under 35 U.S.C. § 102. The Federal Circuit therefore left the PTAB’s invalidity determination intact.

Key Takeaways

• A prior-art reference may anticipate a patent claim through one disclosed operating mode even when the reference also describes alternatives.
• Permissive words such as “may” must be read in context; they do not automatically impose a feature on every embodiment.
• An oral-hearing explanation is not an improper new theory when it elaborates on an issue and evidence already presented to the PTAB.

Why It Matters

The ruling shows how small drafting choices in technical prior art can decide an anticipation challenge. Patent owners cannot turn a possible configuration into a mandatory one when the reference discloses broader alternatives. Detailed expert testimony and consistent visual conventions across patent figures can provide substantial evidence for the Board’s reading.

For PTAB practitioners, the case also illustrates the difference between a genuinely new theory and a permissible refinement of an existing argument. A party that sees a late shift should request relief before the Board; failing to do so makes a later procedural challenge harder.