How Far Can a Broad Claim Be Narrowed by Interpretation? – T 0300/25

Can a broadly drafted claim later be given a narrower meaning by relying on the description and the technical context?

A recent EPO decision, T 0300/25, provides an interesting illustration.

The case concerns a HARQ-ACK feedback mechanism in 5G NR. However, the real dispute was not about the underlying communication protocol. It was about the interpretation of one feature in the claim:

“according to HARQ-ACK timing of the SPS PDSCH”

1. Claim Interpretation

Claim 1 included the following feature:

“adding or removing, by a terminal, the HARQ-ACK of the SPS PDSCH in the HARQ-ACK codebook according to HARQ-ACK timing of the SPS PDSCH.”

The key issue was how the expression “according to HARQ-ACK timing of the SPS PDSCH” should be understood.

The proprietor argued that this expression referred specifically to the PDSCH-to-HARQ feedback timing indicated in the SPS activation DCI, rather than to any HARQ-ACK timing associated with the SPS PDSCH. On that interpretation, the principal prior-art document, D1 (3GPP TS 38.213 V15.0.0), would not disclose the claimed feature.

The Board disagreed.

It held that:

“There is no justification to adopt the appellant’s limited interpretation of the phrase ‘according to HARQ-ACK timing of the SPS PDSCH’.”

According to the Board, the claim merely requires that the SPS PDSCH reception be associated with a HARQ-ACK timing, however configured, and that the HARQ-ACK be added to or removed from the codebook according to that timing.

The claim does not specify that the HARQ-ACK timing must be the PDSCH-to-HARQ feedback timing indicated in the SPS activation DCI.

In other words, the proprietor sought to give the broadly drafted claim a narrower meaning by relying on the description and the technical context. The Board, however, found no justification for adopting that limited interpretation.

2. Why did D8 not change the outcome?

To support its interpretation, the proprietor also relied on D8, an Ericsson contribution (R1-1805189) submitted to 3GPP RAN1.

D8 discusses a situation in which the PDSCH-to-HARQ feedback timing contained in the SPS activation command conflicts with an ongoing HARQ-ACK codebook procedure. In that situation, the UE should ignore the timing indicated in the activation command.

The proprietor therefore argued that D1 could not be performing the claimed adding or removing according to HARQ-ACK timing of the SPS PDSCH.

The Board was not persuaded. It held that D8 does not justify the appellant’s limited interpretation of “HARQ-ACK timing of the SPS PDSCH”. Even if the timing indicated in the SPS activation command is overridden in certain situations, the adding or removing may still be performed according to the HARQ-ACK timing of the SPS PDSCH.

It is also worth noting that the proprietor introduced additional timing-related limitations in the auxiliary requests. The first to fourth auxiliary requests were nevertheless found to lack novelty, while the fifth and sixth auxiliary requests were rejected for lack of clarity before the Board reached the issue of novelty.

3. Takeaways

Although T 0300/25 does not refer to G 1/24, it provides a useful illustration of a practical issue that frequently arises in claim interpretation: a broadly drafted claim cannot be given a narrower meaning without sufficient justification.

The decision also serves as a practical reminder. When using relational expressions such as according to or based on, if a claim is intended to be limited to a particular technical mechanism, that limitation should preferably be expressed in the claim itself, rather than left to be established only through a narrower interpretation based on the description and technical context during later proceedings.


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