Executive Summary: Key Legal and Evidentiary Issues

• Dispute centered on whether Sonos infringed claim 7 of Google’s Canadian Patent No. 2,545,150 regarding adaptive echo and noise control technology.

• Interpretation of key patent terms—“echo cancellation,” “an order,” and “adaptively determine”—was pivotal to the infringement analysis.

• Google argued that the lower court misinterpreted “echo cancellation” and failed to consider broader technological definitions.

• The Federal Court found echo cancellation and noise suppression to be distinct functions, rejecting Google’s broader claim scope.

• Standard of appellate review was debated, focusing on whether claim construction issues were legal or factual in nature.

• The appeal was dismissed with $15,000 in costs awarded to Sonos, affirming no infringement occurred.

Facts and outcome of the case

Background of the dispute
Google LLC appealed a decision of the Federal Court which had ruled in favor of Sonos Inc., finding that Sonos did not infringe claim 7 of Google’s Canadian Patent No. 2,545,150. This patent covered a system for adaptive echo and noise control in electronic devices like smart speakers—technology relevant to both companies' products. The court case specifically examined whether Sonos’s devices used the patented process involving an adaptively determined order of echo cancellation and noise suppression based on the amount of noise.

Key legal issues
Google’s appeal focused on the Federal Court’s interpretation of three critical terms in claim 7: “echo cancellation,” “an order,” and “adaptively determine.” Google contended that the court incorrectly limited “echo cancellation” to methods using reference signals and did not recognize broader industry practices that consider echo a type of noise. It also challenged the interpretation that “an order” required both functions (echo cancellation and noise suppression) to be performed, rather than only one being available. Additionally, the standard of review for these issues—whether questions of law or mixed fact and law—was contested by the parties.

The Federal Court’s reasoning
The trial judge had interpreted the patent from the perspective of a skilled person in the art, relying on expert evidence to distinguish between echo and noise. The Federal Court concluded that echo cancellation and noise suppression are not interchangeable and must be understood as separate processes under the patent. It also held that for there to be an “order,” both functions must be performed in a sequence, not merely available. These interpretations played a central role in finding that Sonos did not infringe the patent.

The Federal Court of Appeal’s decision
Justice Locke, writing for a unanimous panel of the Federal Court of Appeal, upheld the Federal Court’s findings. The appeal was dismissed on the basis that no error had been made in interpreting the key patent terms. The appellate court agreed that the lower court properly assessed the expert evidence and correctly concluded that echo and noise are distinct. As Google conceded that it needed to succeed on both claim construction and application arguments to win the appeal, the failure on interpretation alone was sufficient to dismiss the case.

Outcome and costs
The Federal Court of Appeal dismissed both Google’s appeal of the infringement decision and its related appeal of the costs order. As agreed by the parties, the court awarded Sonos $15,000 in costs. There were no damages assessed or awarded in this appellate ruling.