T 2829/18 (Handling of a "Timer_Poll_Periodic" timer for an RLC of a UMTS wireless communications system) 28-07-2021

Reasons for the Decision

1. The application concerns the handling of a "Timer_Poll_Periodic" timer for a Radio Link Control Acknowledge Mode (RLC AM) entity of a UMTS wireless communications system.

2. Admissibility (Article 13(1) RPBA)

The set of claims according to the sole request differs from the set of claims considered in the impugned decision in that claims 1, 3, 4 and 6 have been deleted.

Since deleting entire claims furthers procedural economy, the board decides to admit the sole request into the proceedings.

3. Clarity (Article 84 EPC)

The board notes that the impugned decision raised an objection of lack of clarity with respect to claim 3. Since claim 3 is not in the set of claims under scrutiny, this objection is now irrelevant.

4. Added subject-matter (Article 76(1) EPC)

Objections regarding added subject-matter were raised with respect to claims 3, 4 and 6 during the proceedings. As these claims are not in the present set of claims, the objections no longer apply.

5. Novelty (Article 54(1) EPC)

In line with the impugned decision and as argued by the appellant, the board holds that document D2 fails to disclose feature (1.2) of claim 1, which thus constitutes the distinguishing feature. The board finds that document D2 explicitly discloses that the "RESET PDU is used ... to reset all ... protocol timers" (see item b) in section 9.1.2 on page 18), which is clearly different from "not stopping" the timer.

The same applies by analogy to feature (2.4) of claim 2, since the receiving of the RESET ACK PDU mentioned there concerns, in the context of the reset procedure, the entity corresponding to the entity which received the RESET PDU.

The subject-matter of claims 1 and 2 is therefore novel.

6. Inventive step (Article 56 EPC)

6.1 Closest prior art

In the statement setting out the grounds of appeal, the appellant argues that document D1, rather than document D2, should be regarded as the closest prior art, adding that document D1 supersedes the preceding versions of the same standard, including document D2. It argues that the skilled person would not start from an older version, since this would put them at risk of not complying with the standard.

In the impugned decision, the examining division followed the reasoning provided by the board of appeal in section 9.2.5 of decision T 2330/10 concerning the grandparent application.

This board is not convinced by the appellant's argument and confirms the reasoning provided on the same question in decision T 2330/10. In particular, this board considers that the skilled person would assume that any standard document issued by ETSI on the subject at issue would be a promising starting point. The board notes that standardisation bodies might revert to a superseded version of a standard if later developments turn out to be disadvantageous. Furthermore, the board notes that "the state of the art shall be held to comprise everything made available to the public ... before the date of filing of the European patent application" (Article 54(2) EPC). Therefore, what is claimed may also be examined for an inventive step based on an earlier prior-art document, such as document D2 (in line with decision T 0113/00, item 3.7).

As a consequence, the board considers that it has to be established whether the claimed subject-matter would have been obvious to the skilled person in view of either of documents D1 and D2.

6.2 Technical effect and objective technical problem

In the impugned decision, the examining division formulated the technical problem to be solved starting from document D2 as "how to effectively operate the Timer_Poll_Periodic timer during and following a reset procedure".

The appellant argues that the cited prior art discloses that this timer is reset during a reset procedure (see document D2, item b) in section 9.1.2 on page 18) and thus stopped. The appellant adds that other mechanisms for implementing a poll are also disclosed (see document D2, section 9.7.1 on page 35). Thus, compared to the solution of document D2, where the timers are reset, the technical effect achieved by the distinguishing feature is that pending PDUs are considered earlier. The resulting objective technical problem is "how to modify the known reset procedure such that pending PDUs are considered earlier".

The board notes that document D2 indeed discloses that, during a reset procedure, all timers are reset (see document D2, item b) in section 9.1.2 on page 18), which implies stopping them, i.e. terminating their operation. Even if the timer were restarted immediately after the reset, it would in any case expire later than if it had not been stopped, in accordance with the claimed solution. Essentially, in line with what has been presented by the appellant, the board considers that the objective technical problem may be formulated as "avoiding undue polling delay in the context of a reset procedure".

6.3 Obviousness

The appellant argues that, since document D2 discloses causing a poll without using a timer at all, the skilled person has no motivation to act against the teaching of document D2 that all timers are to be reset/stopped during a reset procedure. Therefore, the skilled person would not arrive at the distinguishing feature without employing inventive skill.

The board considers that the skilled person could have recognised that, when performing the reset procedure, it is only necessary to reset specific timers in order to achieve synchronisation of the RLC entities, which is described as being the purpose of the RLC reset procedure. Moreover, the skilled person could have realised the existence of the above problem and considered solving it by not stopping the "Timer_Poll_Periodic" timer, in addition or as an alternative to the other ways of effectuating a poll disclosed in document D2. However, document D2 does not give the skilled person any pointer towards this problem or towards the claimed solution. On the contrary, document D2 discloses resetting the timer, which implies stopping it, i.e. the opposite of distinguishing feature (1.2). In view of the above, the skilled person would not arrive at the distinguishing features without employing inventive skill. Therefore, the subject-matter of claim 1 involves an inventive step over what is known from document D2.

6.4 Since the feature distinguishing the subject-matter of claim 1 from document D2 also distinguishes it from document D1, and as D1 likewise fails to mention any pointer towards the claimed solution, the board finds that the subject-matter of claim 1 involves an inventive step over what is known from document D1 as well.

6.5 Similarly, the subject-matter of claim 2 involves an inventive step over what is known from the cited prior art since it contains the same distinguishing feature as claim 1.

6.6 In view of the above, the sole request is allowable.

7. Consequently, the appeal is allowable.