The decision T 1580/23 of the Boards of Appeal 3.5.05 of the European Patent Office (EPO) is an appeal decision concerning an opposition against the European patent EP3395029. This decision dated May 28, 2025, and published June 10, 2025, addresses the validity of the patent in question, which was revoked by the Opposition Division of the EPO.
The patent EP3395029, titled "Methods, apparatuses and computer program product for PDU formatting according to SDU segmentation," is owned by Nokia Solutions and Networks Oy. The initial opponent was Guangdong OPPO Mobile Telecommunications Corp., Ltd., which withdrew its opposition before the final decision.
Presentation of the Invention
The patent EP3395029 describes a method for segmenting and formatting protocol data units (PDUs) according to service data units (SDUs) in wireless communication systems, particularly in the context of 5G networks.
Claim 1 of the main request reads, according to the numbering to the Board of Appeal, as:
1 A method comprising
1.1 first determining for a PDU, to be provided to a receiver
entity,
1.1.1 whether a segment of an SDU, is to be included in the PDU
and, if so,
1.2 second determining the position of the segment relative to the SDU,
1.3 the PDU comprising a header part and a data field part;
1.4 determining whether to include information in the header part in dependence of the first determining, and, if so,
1.5 determining the content of the information in the header part in dependence on the second determining;
1.6 providing the PDU to a receiver entity
1.7 determining that the position of the segment of the SDU is between a first segment and a last segment of the SDU and
1.8 determining therefore that the content of the information in the header part indicates segment offset.
The figure 4 of the patent EP3395029 shows an example of a PDU with different fields with the frame, including in particular a header, LI (Length Information) fields, and data, with fields called data field element (DFE):
Procedure and Decision
Main Request and Auxiliary Requests 1 to 3
The main request and auxiliary requests 1 to 3 were rejected for lack of novelty in view of document D4 (CN 101039170 A). Document D4 describes a similar method where a sending entity first determines whether a segment of an SDU should be included in a PDU and, if so, determines the position of the segment relative to the SDU. The Board of Appeal found out that D4 disclosed all the features 1to 1.8
Auxiliary Requests 4 to 7b
The Board of Appeal found out that D4 failed to disclose the distinguishing features 1.9 and 1.10 of the auxiliary requests 4 to 7b:
1.9 the header part comprises [a] data field element (DFE) information[field], the DFE indicative of the number of DFEs in the data field and
1.10 comprising providing DFE information[field] after the second bit of the framing information and before the first bit of the framing information.
The patent proprietor submitted that that the distinguishing features 1.9 and 1.10 (more specifically the presence and the placement of the "data field element (DFE)" within the header) enabled a receiver to determine the data field start position in the PDU as soon as possible.
The Board of Appeal however assessed, at point 2.2.4, that the technical effect alleged by the patent proprietor was not convincing, because determining the data field start could not be achieved only by a field "that specifies the amount of SDUs (data field elements (DFEs)) carried in the PDU", but could be achieved if the three conditions listed below are met:
(a) the number of DFEs is known,
(b) all the corresponding LI fields are of the same predefined fixed size and
(c) there are no other fields within the PDU between the LI fields and data fields or - if present - their length is also known in advance
According to the Board of Appeal, the distinguishing features 1.9 and 1.10 only relate to condition (a).
In absence to explicit feature relative to conditions (b) and (c) in the claims, the patent proprietor further tried to rely on the decision G2/21 to assess that it was not necessary to introduce features relative to the conditions (b) and (c) in the claim to achieve the technical effect, as the conditions (b) and (c) could be supplemented to the information contained in the original application by the skilled person's common technical knowledge. In the decision G2/21, the Enlarged Board of Appeal of the EPO came to the conclusion that " A patent applicant or proprietor may rely upon a technical effect for inventive step if the skilled person, having the common general knowledge in mind, and based on the application as originally filed, would derive said effect as being encompassed by the technical teaching and embodied by the same originally disclosed invention. »
More specifically, the patent proprietor argued that the E and LI fields were well defined in the 3GPP standard TS 136 322 V12.3., section 6.2.2.5 0, so that it would not be necessary to explicitly introduce conditions (b) and (c) in the claim, while the description of the patent mentioned the possible compliance with 3GPP standards.
In the point 2.2.6 of the decision, the Board of Appeal however held, in line with the decision T 2010/22 dated earlier this year, that the decisive question remained whether the claimed features themselves credibly bring about the technical effect over the whole range claimed. In the present case, the wording of the claim was not restricted to 3GPP standard TS 136 322 V12.3.0 - or any other 3GPP standard -, so that the sole mention of such a standard in the description was not sufficient to credibly achieve a technical effect relying upon that standard.
Conclusion and discussion
This decision is consistent with previous case law of the Boards of Appeal of the EPO, in that a technical effect can only be relied on for the assessment of inventive step, if it is credibly achieved over the whole range of the claimed subject-matter.
This decision also illustrates, as the previous decision T 2010/22, that the findings of the recent decision G2/21 cannot be extended for claiming technical effects on the ground of information contained in the description, when the corresponding features do not restrict to the whole breadth of the claim.
In the present case, the odds of demonstrating a technical
effect would have been much higher if the claimed contained all the
information allowing to determine the start of the data fields. For
example, the patent proprietor could have explicitly added the
additional information required by a specific standard. An even
better situation could have been obtained if the claim contained
information allowing to take into account the fields other than
data fields in a way which in the same time would credibly allow to
determine the size of the other data fields, and not be restricted
to a particular standard.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
